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Consider ALL the Options Before Your Cataract Surgery: Working Through What’s Best For You

Aug 10, 2013 - 35 comments

Decisions before cataract surg

Consider ALL the Options Before Your Cataract Surgery: Working Through What’s Best For You

John C. Hagan, MD, Fellow American Academy of Ophthalmology, Fellow American College of Surgeons.

Many decisions have to be made before having cataract surgery. The first is whether you need the surgery or not. Assuming you have made the decision to have surgery this is a discussion of the many options and choices you have.  THERE IS NO “BEST” TYPE OF PHACOEMULSIFICATION CATARACT SURGERY AND NO “BEST” INTRAOCULAR LENS. NO TARGETED POST SURGERY REFRACTIVE ERROR IS FOR EVERYONE. THESE DECISIONS WILL VARY FROM PERSON TO PERSON AND MUST BE INDIVIDUALIZED.  

We all have different visual needs.  Cataract surgery will be done earlier on a person needing perfect vision in all lighting circumstances, think airline pilots, truck drivers and heart surgeons. Surgery is done much later, if at all, on the very, very elderly, functioning combative or uncooperative dementia patients, those with terminal illnesses. In general cataract surgery is generally offered when a person is experiencing moderate or severe visual difficulties in activities they enjoy or need to do and the cataract is the sole or main cause.

Although the person is usually the one that makes the determination about how much of a problem his/her vision is in some cases surgery is strongly recommended by the ophthalmologist, optometrist or family.  Examples include inability to drive safely or legally; difficulty seeing the inside of the eye, major progressive physical or psychiatric disease, and if center of the cataract is getting “rock hard” (so called ‘brunescent or brown/black cataract) or could start to break up in the eye (so called ‘too ripe’).

Assuming cataract surgery is appropriate, the decisions that must be made include: which eye to operate on first, what type of IOL to insert, desired-targeted post-operative refractive error, how much glasses will need to be worn post operatively [NOTE: glasses are almost uniformly needed post operatively and are usually modern progressive bifocals]  SOME OF THE TIME a small % of people after cataract surgery can function without glasses or with inexpensive over the counter reading glasses.  Equally important is the choice of surgeon-ophthalmologist (Eye MD: a physician Doctor of Medicine or Doctor of Osteopathy that has been to medical school, medical-surgical residency and in many cases taken a special surgical fellowship.  Ophthalmologists provide a complete range of medical and surgical services.  Eye MDs must be distinguished from non-physician optometrists (OD) and opticians).

This discussion is not meant to be encyclopedic nor to give you “the answer.” As stated previous “the correct” answer will be different for different people. Informative is based on the most common questions posted on the American Academy of Ophthalmology MedHelp Eye Forums.

1. Where there is a difference of more than 1.50 diopters between the eyes post operatively glasses are often difficult or impossible to adjust to. The condition is called "aneisometrophia".  Part of the problem is due to the difference in image size each eye has with the glasses on; this is called “aneisokonia”.  Seek out Eye Forum posts on this problem by JodieJ. She had this problem post operatively and she clearly outlines her struggle and eventual success.
2. With modern cataract surgery not only do we try and make the person see better but we want the best possible vision without glasses and the two eyes to "work together" comfortably.  Tests are done preoperatively to help pick the proper IOL power to leave a targeted post op refractive error. This is not an exact science and the margin of error is +/- 0.50 but INCREASES with high myopia (long eye) or high hyperopia (short eye), eyes with previous RK, lasik, injury or additional eye diseases.
3. Typically the targeted post op refraction is between 0.00 (not needing glasses for distances of 20 feet (6 meter) or more) and -3.00 which has great vision for tiny detail at reading distance 13-14 inches.  Any difference of greater than 1.50 diopter post op may have trouble with glasses (some people tolerate much larger numbers but you never know). The range of relatively clear vision without glasses on is called “depth of focus” and will vary from person to person based on things like pupil size and corneal structure.
4. Some people that are highly myopic or highly hyperopic that do not have cataracts elect to have the lens of the eye removed (same technique as cataract surgery) and an intra-ocular lens (IOL) put in to eliminate thick glasses and improve vision without glasses. It is called "clear lensectomy" or "clear lens cataract surgery” or “refractive lens exchange”. This is done to reduce the thickness of their glasses or make them much more glasses independent.  We are not discussing whether that is appropriate surgery. The IOL and refractive problems are the same as those having cataract surgery.
5. A refractive error that makes some people happy post cataract surgery and often enables them to function without glasses for many things is 0.00 in the dominant eye for distance and -1.25 or -1.50 for the "reading eye." In good lighting they often can read without glasses. With glasses (the RX would be 0.00 distance eye -1.50 near eye and reading add of +3.00 diopters and the type glasses a no line bifocal) The glasses would be worn when best binocular vision is needed e.g. driving especially at night, sporting events or sports participation (gives the best depth perception) and prolonged reading or computer use. (This is called mini-monovision with distance bias)  If a person wanted to shift the clearest vision to intermediate and near (example some accountants, engraver, graphic design artist) the numbers change: -1.25 intermediate vision and -2.75 or -3.00 for reading/near eye. The glasses RX would be -1.25 and -2.75 with +3.00 add in progressive bifocals.
6.   If the person having surgery has astigmatism (aspherical or not round cornea) then the glasses RX will need a "cylinder" lens (second and third part of RX indicated by “cylinder and axis).  The vision without glasses will be less clear due to uncorrected astigmatism.   Assuming our models listed in above example and 1.50 diopters of corneal astigmatism the mini-monofocal distance bias will be 0.00 +1.00 axis 180 and the intermediate/near bias eye will be -1.25 +1.00 axis 180 and a +3.00 add in no line bifocals. This is more blurry vision than 0.00 at distance or -1.25 for near/intermediate.
7. NOTE: glasses can be written in PLUS CYLINDERS OR MINUS CYLINDERS (you can tell which by whether the sign in front of the cylinder number is + (plus) or – (minus) The two formula look very different and prescriptions in plus cylinder cannot be compared with minus cylinder.  Think about your body weight: your weight numbers will look very different whether it is recorded as pounds or kilograms since 1 kg = 2.2 lbs.  A discussion of this subject and the formula for changing plus cylinder to minus cylinders or vice versa is available at   http://en.wikipedia.org/wiki/Eyeglass_prescription
8.  Correction of astigmatism at the time of cataract surgery is desirable.  There are different ways to accomplish this; some are simple while others complex. Some will not generate extra surgical or IOL fees but others will:  placement of incision along steep axis of cornea-make incision larger-use more steroid drops; surgical or laser corneal relaxing incisions; toric IOLs or toric mutifocal IOLs; rounding the cornea at time of surgery with brand new (2013) femtosecond laser; post operatively using  lasik surgery to remove residual astigmatism.
9. In cases where one eye has a cataract that is symptomatic and causing problems with important functions such as driving, reading, recognizing faces, glare avoidance, etc.  but the other eye has no cataract or a cataract that is small and not troublesome in people with large refractive errors special attention needs to be made to choice of IOL.   If targeting of the patient/surgeon desired refractive error post operatively generates a difference in the two eyes greater than 1.50 diopters, the person should know it may be difficult to wear glasses conformably and/or glasses (no line bifocals usually) plus a contact lens on the un-operated eye. Or  lasik or other post-operative refractive surgery may need to be done on the un-operated or operated eye to help them work together.
10. The problems outlined in #9 above may require surgery on the “other” eye to re-establish the ability of the eyes to work together with and without glasses. This can be true even if the cataract is small or even non-cataractous.  
11. So called “Premium” IOLs (toric, multi-focal and accommodating) are used to reduce dependence on glasses. For almost all people they do not eliminate glasses 100% of the time. Even people that consider themselves “not needing glasses after cataract surgery” often wear glasses for special purposes such as night driving and prolonged reading or computer use. Premium IOLs are more expensive, have a greater chance of complication (although in the hands of an experienced ophthalmic surgery the risk is small), and produce unwanted glare and scattered light (dysphotopsia) more than modern aspheric monofocal IOLs.  
12. It is also fair to say that some ophthalmology and optometry offices exert effort to encourage people to “upgrade’ from monofocal IOLs to “premium” IOLs. In sales this is not called “upgrading” but “upselling”. Also it’s important to know that some optometrists receive part of the surgical payment for cataract/IOL surgery, this is known as “co-management”.  Premium IOLs are not better than monofocal IOLs; they are not designed to make everyone 100% glasses independent all the time. Most ophthalmologists and optometrists do present a fair discussion of each type of IOL and let an informed patient make the choice that suits them best.
13. While cataract/IOL surgery is the most common type of surgery done on adults and has a very low complication rate it is not risk free NO SURGERY IS RISK FREE; THAT’S WHY YOU READ (or have read to you) AND SIGN A SURGICAL CONSENT FORM THAT INFORMS YOU OF THE DIAGNOSIS, YOUR OPTIONS AND POSSIBLE RISKS AND COMPLICATIONS. These risks cannot be entirely eliminated. No surgery is entirely “routine and risk free”   Think about driving an automobile. Driving is “routine” to most of us. Yet everyday there are people injured or killed in automobiles. We continue to drive because, with care, the risk is relatively low. Think of cataract surgery the same way.
14. In most all cases cataract surgery is elective. You can take your time and make these important decisions. There is nothing wrong with seeking a second opinion from a different ophthalmic surgeon. You can also access the many helpful discussions on these topics at the two AAO Medhelp Eye Forums by using the search feature or looking in the archives.

15. This information is not meant to give you specific recommendations. This posting is for information purposes only. You should rely on your own multi-source research and discussions with your ophthalmologist, optometrist and personal physician.


May 08, 2013 - 1 comments


Effect of Day Length on Eye Growth, Myopia Progression, and Change of Corneal Power in Myopic Children

Dongmei Cui, MD, PhD, Klaus Trier, MD, Søren Munk Ribel-Madsen, MSc, PhD


Because of the northern location of Denmark, the length of the day over the year varies from 7 to 17.5 hours. Experimental and clinical results suggest that the development of myopia may be related to ambient light exposure. The purpose of current study was to investigate whether axial eye growth, myopia progression, or corneal power change in Danish myopic children varies with the length of the day.


Cross-sectional study.


Two hundred thirty-five children 8 to 14 years of age found to have myopia during screening for a clinical trial (ClinicalTrial.gov identifier, NCT00263471; accessed December 6, 2005). All children found to have any value of spherical equivalent that was myopic (<0 diopters [D]) at the first of 2 visits were included.


Cycloplegic refraction was measured using an autorefractor, axial eye length, and corneal power using an automatic combined noncontact partial coherence interferometer and keratometer. The accumulated number of daylight hours during the measurement period was calculated for each participant using an astronomical table.

Main Outcome Measures

Change over 6 months in axial length, refraction, and corneal power.


Accumulated hours of daylight ranged from 1660 to 2804 hours. Significant correlations were found between hours of daylight and eye elongation (P = 0.00), myopia progression (P = 0.01), and corneal power change (P = 0.00). In children with an average of 2782±19 hours of daylight, axial eye growth was 0.12±0.09 mm, myopia progression was 0.26±0.27 D, and corneal power change was 0.05±0.10 D per 6 months, whereas in children with an average of 1681±24 hours of daylight, axial eye growth was 0.19±0.10 mm, myopia progression was 0.32±0.27 D, and corneal power change was −0.04±0.08 D per 6 months.


Eye elongation and myopia progression seem to decrease in periods with longer days and to increase in periods with shorter days. Children should be encouraged to spend more time outside during daytime to prevent myopia.


Outdoor Activity during Class Recess Reduces Myopia Onset and Progression in School Children

Pei-Chang Wu, MD, PhD, , Chia-Ling Tsai, BDS, MS, Hsiang-Lin Wu, BS


The aim of this study was to investigate the effect of outdoor activity during class recess on myopia changes among elementary school students in a suburban area of Taiwan.


Prospective, comparative, consecutive, interventional study.


Elementary school students 7 to 11 years of age recruited from 2 nearby schools located in a suburban area of southern Taiwan.


The children of one school participated in the interventions, whereas those from the other school served as the control group. The interventions consisted of performing a recess outside the classroom (ROC) program that encouraged children to go outside for outdoor activities during recess. The control school did not have any special programs during recess.

Main Outcome Measures

Data were obtained by means of a parent questionnaire and ocular evaluations that included axial length and cycloplegic autorefraction at the beginning and after 1 year.


Five hundred seventy-one students were recruited for this study, of whom 333 students participated in the interventional program, and 238 students were in the control school. At the beginning of the study, there were no significant differences between these 2 schools with regard to age, gender, baseline refraction, and myopia prevalence (47.75% vs. 49.16%). After 1 year, new onset of myopia was significantly lower in the ROC group than in the control group (8.41% vs. 17.65%; P<0.001). There was also significantly lower myopic shift in the ROC group compared with the control group (−0.25 diopter [D]/year vs. −0.38 D/year; P = 0.029). The multivariate analysis demonstrated that the variables of intervention of the ROC program and higher school year proved to be a protective factor against myopia shift in nonmyopic subjects (P = 0.020 and P = 0.017, respectively). For myopic subjects, school year was the only variable significantly associated with myopia progression (P = 0.006).


Outdoor activities during class recess in school have a significant effect on myopia onset and myopic shift. Such activities have a prominent effect on the control of myopia shift, especially in nonmyopic children


Body Stature Growth Trajectories during Childhood and the Development of Myopia

Kate Northstone, PhD, Jeremy A. Guggenheim, PhD, Laura D. Howe, PhD, Kate Tilling, PhD, , Lavinia Paternoster, PhD, John P. Kemp, MSc, George McMahon, PhD,   Cathy Williams, PhD


Stature at a particular age can be considered the cumulative result of growth during a number of preceding growth trajectory periods. We investigated whether height and weight growth trajectories from birth to age 10 years were related to refractive error at ages 11 and 15 years, and eye size at age 15 years.


Prospective analysis in a birth cohort.


Children participating in the Avon Longitudinal Study of Parents and Children (ALSPAC) U.K. birth cohort (minimum N = 2676).


Growth trajectories between birth and 10 years were modeled from a series of height and weight measurements (N = 6815). Refractive error was assessed by noncycloplegic autorefraction at ages 11 and 15 years (minimum N = 4737). Axial length (AXL) and radius of corneal curvature were measured with an IOLMaster (Carl Zeiss Meditec, Welwyn Garden City, U.K.) at age 15 years (minimum N = 2676). Growth trajectories and an allelic score for 180 genetic variants associated with adult height were tested for association with refractive error and eye size.

Main Outcome Measures

Noncycloplegic autorefraction at ages 11 and 15 years, and AXL and corneal curvature at age 15 years.


Height growth trajectory during the linear phase between 2.5 and 10 years was negatively associated with refractive error at 11 and 15 years (P<0.001), but explained <0.5% of intersubject variation. Height and weight growth trajectories, especially shortly after birth, were positively associated with AXL and corneal curvature (P<0.001), predicting 1% to 5% of trait variation. Height growth after 2.5 years was not associated with corneal curvature, whereas the association with AXL continued up to 10 years. The height allelic score was associated with corneal curvature (P = 0.03) but not with refractive error or AXL.


Up to the age of 10 years, shared growth mechanisms contribute to scaling of eye and body size but minimally to the development of myopia.

Financial Disclosure(s)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.


Jul 14, 2011 - 4 comments


Utility Values Associated With Vitreous Floaters
Ajeet M. Wagle
AffiliationsDepartment of Ophthalmology and Visual Sciences, Khoo Teck Puat Hospital, SingaporeDepartment of Ophthalmology and Visual Sciences, Alexandra Hospital, SingaporeEye Clinic, Jurong Medical Center, SingaporeFaculty of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, SingaporeInquiries to Ajeet M. Wagle, Department of Ophthalmology and Visual Sciences, Khoo Teck Puat Hospital, 90 Yishun Central, Singapore 768828
, Wei-Yen Lim
AffiliationsDivision of Epidemiology and Public Health, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
, Tiong-Peng Yap
AffiliationsDepartment of Ophthalmology and Visual Sciences, Alexandra Hospital, Singapore
, Kumari Neelam
AffiliationsDepartment of Ophthalmology and Visual Sciences, Khoo Teck Puat Hospital, SingaporeDepartment of Ophthalmology and Visual Sciences, Alexandra Hospital, SingaporeEye Clinic, Jurong Medical Center, Singapore
, Kah-Guan Au Eong

To ascertain the health-related quality of life associated with symptomatic degenerative vitreous floaters.

Cross-sectional questionnaire survey.

In this institution-based study, 311 outpatients aged 21 years and older who presented with symptoms of floaters were enrolled. Data from 266 patients (85.5%) who completed the questionnaire were analyzed. Utility values were assessed using a standardized utility value questionnaire. The time trade-off (TTO) and standard gamble (SG) for death and blindness techniques were used to calculate the utility values. Descriptive, univariate, and multivariate analyses were performed using Stata Release 6.0.

The mean age of the study population was 52.9 ± 12.02 years (range, 21–97). The mean utility values were 0.89, 0.89, and 0.93 for TTO, SG (death), and SG (blindness), respectively. Patients aged ≤55 years reported significantly lower SG (blindness) utility values when compared with patients above 55 years of age (age ≤55 = 0.92, age >55 = 0.94, P = .007). Utility measurements did not demonstrate significant relationship with any of the other socio-demographic variables examined in this study. The utility values did not demonstrate any significant relationship with other ocular characteristics such as duration of symptoms, presence of a posterior vitreous detachment, and presence or severity of myopia.

Symptomatic degenerative vitreous floaters have a negative impact on health-related quality of life. Younger symptomatic patients are more likely to take a risk of blindness to get rid of the floaters than older patients.

Floaters are entoptic images of opacities in the vitreous cavity that usually occur as a result of degenerative changes in the vitreous gel such as vitreous syneresis, condensation of vitreous fibers, and posterior vitreous detachment (PVD).1, 2, 3 Degenerative vitreous floaters may become asymptomatic with passage of time. However, in some patients, symptomatic degenerative vitreous floaters persist for many years and can potentially affect health-related quality of life in several ways. Floaters can result in intermittent blurred vision, glare and haze attributable to migration of vitreous opacities into the visual axis, and interference with important activities of daily living such as reading, driving, and near work.3

Individuals with symptomatic degenerative floaters constitute a fair proportion of patients seen in ophthalmology clinics in Singapore. Myopia, which is often associated with degenerative floaters, is a growing public health problem with high prevalence rates in Singapore.3, 4, 5 The health-related quality of life associated with floaters is not well understood. Of note, Snellen acuity, the standard test of visual function in a clinical setting, is unable to quantify visual disability associated with vitreous floaters on day-to-day functioning and overall quality of life.1, 3, 6 Although surgical interventions such as Nd:YAG laser vitreolysis, deep anterior vitrectomy combined with cataract surgery, and pars plana vitrectomy are available, they have been offered to patients with symptomatic floaters only rarely.1, 3, 6

Health-related quality of life is playing a vital role in every specialty of medicine because of the increasing importance of patient preferences and escalating healthcare costs. Utility values, originally described by Von Neumann and Morganstern in 1940, allow an objective quantification of the functional quality of life associated with a specific disease state.7, 8, 9 By convention, a utility value of 1.0 implies a perfect health state whereas a value of 0.0 indicates the worst possible health state or death. The closer the value is to 1.0, the better is the perceived health-related quality of life. Currently, utility values modified by Brown and associates are used for measuring health-related quality of life in patients with eye diseases.10 Utility values are measured using a number of techniques. The time trade-off (TTO) and standard gamble (SG) methods represent 2 common techniques of eliciting preferences under the utility theory. The TTO utility measures the numbers of years of remaining life that an individual is willing to trade off for a hypothetical technology that restores perfect vision, whereas the SG utility assesses the risks associated with a hypothetical technology that the patient is willing to take to return to the perfect health state.

Utility values have been measured for a variety of eye diseases that affect health-related quality of life such as diabetic retinopathy, age-related macular degeneration, glaucoma, and myopia.9, 11, 12, 13, 14, 15 Understanding the impact of floaters on the overall health-related quality of life can be invaluable in deciding possible treatment options in specific subgroups of patients. In this study, we assess the utility values in patients presenting primarily with a history of floaters.

Back to Article Outline

In this questionnaire-based study, we enrolled consecutive patients presenting primarily with a history of floaters to the Department of Ophthalmology and Visual Sciences in Alexandra Hospital, Singapore, from April 1, 2006 to December 31, 2007.

Patients were eligible to participate in the study if they satisfied the following criteria: age 21 years and above, history of floaters in 1 or both eyes, best-corrected visual acuity (BCVA) better than 20/30 in the better-seeing eye, no significant coexisting retinal pathology, and willingness to give an informed consent. Patients with acute-onset floaters (defined as floaters of less than 4 weeks' duration), and high myopia (spherical equivalent equal to or greater than −6.0 diopters [D]) were also included in the study. Patients with floaters secondary to other eye conditions such as vitreous hemorrhage, vitreous inflammation, and ocular trauma were excluded from the study. Similarly, patients with dense corneal or lenticular opacities that hindered optimal visualization of the fundus or those with concomitant ocular diseases resulting in loss of vision were not eligible to participate in the study. Lastly, patients were not enrolled if they were unwilling to answer and/or unable to understand utility value questionnaires because of psychiatric problems or dementia.

A comprehensive eye examination including Snellen BCVA, slit-lamp biomicroscopy, and a dilated fundus examination using indirect ophthalmoscopy was performed for each patient. Additionally, in all participants, demographic and socioeconomic data, such as age, gender, ethnicity, educational status, occupation, housing, personal and family income, and total number of family members, were recorded.

A single trained research assistant interviewed the patients using a standardized utility value questionnaire.11, 12, 15 Where necessary, the questionnaire was interpreted by the interviewer in the patients' preferred language. During the face-to-face interviews, the research assistant encouraged the patients to ask questions if they were unable to comprehend the utility questionnaire.

Utility values were calculated using the commonly used techniques of TTO and SG for death and blindness. TTO utility value was calculated based on the time traded in years over the expected number of years of the respondent's remaining life that he/she is willing to give up for a hypothetical technology to restore perfect health (TTO utility = 1 – [time traded in years/estimated number of years of remaining life]). Standard gamble utility was calculated as the amount of risk (in percentage) of death or blindness that a respondent is willing to take for a hypothetical technology that may restore perfect vision respectively (SG utility = 1 – [amount of risk of death or blindness in percentage that the respondent is willing to take/100]).

Data Analysis
Descriptive, univariate, and multivariate analyses were performed using Stata Release 6.0 (Stata Corporation, College Station, Texas, USA). The mean and median TTO, SG (death), and SG (blindness) utilities were calculated for all patients with floaters. Utility values were compared across different age groups, socio-demographic groups, and patients' presentation characteristics using the Wilcoxon rank sum test and Kruskal-Wallis test. These nonparametric tests were used for statistical analysis because the normality assumption needed for parametric tests was not satisfied by our sample. All P values quoted are 2-sided and considered statistically significant when the values are below .05. Multiple linear regression analysis was performed after adjusting for the effect of confounding factors.

Back to Article Outline

In this cross-sectional study, 311 consecutive patients presenting primarily with a history of floaters were enrolled. Of these, data from 266 patients (85.5%) who completed the questionnaire were analyzed. The details of demographic and socioeconomic characteristics are presented in Table 1.

TABLE 1. Demographic and Socioeconomic Characteristics of Study Population With Symptomatic Degenerative Vitreous Floaters (N = 266)
Demographic Characteristics Number (%)
Mean age (range), years 52.9±12.02(21–97)
Sex ratio (male:female) 0.78:1
Chinese (%) 239(89.9%)
Non-Chinese (%) 37(10.1%)
Housing type  
Public housing estates 215(81.4%)
Private housing 49(18.6%)
Education status  
No formal education/primary education 51(19.3%)
Secondary education 119(44.9%)
Tertiary education 95(35.8%)
Average number of family members (range) 3.48(1-7)
Employment status (%)  
Employed 174(65.9%)
Unemployed/retired 90(34.1%)
Average monthly income (USD)  
Personal 1665
Family 2371
USD = United States dollars.

Utility Values
The mean utility values for our study population were 0.89, 0.89, and 0.93 for TTO, SG (death), and SG (blindness), respectively.

Utility Values and Demographics
The details of utility values associated with various demographic factors are shown in Table 2. Time trade-off and SG (death) utility values did not differ significantly with age in patients with floaters (TTO: age ≤55 = 0.89, age >55 = 0.89, P = .16; SG [death]: age ≤55 = 0.88, age >55 = 0.90, P = .07). However, patients aged ≤55 years reported lower SG (blindness) utility values when compared with patients >55 years of age (age ≤55 = 0.92, age >55 = 0.94, P = .007).

TABLE 2. Utility Values Associated With Various Demographic and Socioeconomic Factors in Patients With Symptomatic Degenerative Vitreous Floaters
Characteristic n TTO Mean (Median) P Value n SG (Death) Mean (Median) P Value n SG (Blindness) Mean (Median) P Value
All 266 0.89(1.00)  266 0.89(1.00)  266 0.93(1.00)  
Age   .16   .07   .007a
≤55 years 146 0.89(0.96)  146 0.88(1)  146 0.92(1)  
>55 years 120 0.89(1)  120 0.90(1)  120 0.94(1)  
Gender   .52   .20   .39
Male 117 0.89(1)  117 0.88(1)  117 0.92(1)  
Female 149 0.90(1)  149 0.89(1)  149 0.94(1)  
Race   .57   .26   .54
Chinese 239 0.89(1)  239 0.88(1)  239 0.93(1)  
Non-Chinese 27 0.92(1)  27 0.92(1)  27 0.92(1)  
Personal income   .26   .29   .65
No income 121 0.90(1)  121 0.89(1)  121 0.93(1)  
US$ 1–1333.3 62 0.87(0.9)  62 0.86(1)  62 0.94(1)  
US$ >1333.3 83 0.90(1)  83 0.90(1)  83 0.91(1)  
Household income   .57   .77   .46
No income 113 0.89(1)  113 0.88(1)  113 0.93(1)  
US$ 1–1333.3 78 0.89(0.953)  78 0.90(1)  78 0.94(1)  
US$ >1333.3 75 0.90(1)  75 0.89(1)  75 0.92(1)  
Education   .13   .93   .59
No formal education/primary education 51 0.92(1)  51 0.87(1)  51 0.91(1)  
Secondary education 119 0.87(1)  119 0.88(1)  119 0.93(1)  
Diploma/degree 95 0.90(1)  95 0.91(1)  95 0.95(1)  
Housing type   .44   .46   .57
Public (1–4 room flats) 120 0.88(1)  120 0.90(1)  120 0.92(1)  
Public (>5 room flats) 95 0.89(1)  95 0.87(1)  95 0.93(1)  
Private 49 0.91(1)  49 0.90(1)  49 0.96(1)  
Occupation   .13   .19   .48
Employed/student 174 0.89(1)  174 0.88(1)  174 0.93(1)  
Housewife/retired/non-employed 90 0.90(1)  90 0.90(1)  90 0.93(1)  
SG = Standard gamble; TTO = time trade-off; US$ = United States dollar (1 US$ = 1.50 Singapore $).

aSignificant P value 1 month 124 0.90(1)  124 0.89(1)  124 0.93(1)  
Laterality of presentation   .89   .36   .75
Unilateral 113 0.89(1)  113 0.89(1)  113 0.93(1)  
Bilateral 153 0.90(1)  153 0.89(1)  153 0.9391)  
Myopia   .55   .26   .92
No myopia 107 0.90(1)  107 0.86(1)  107 0.91(1)  
Myopia in at least 1 eye 159 0.89(1)  159 0.90(1)  159 0.95(1)  
Severity of myopia   .41   .35   .58
SE less than −6.0 D 100 0.92(1.00)  115 0.92(1.00)  116 0.94(1.00)  
SE greater than or equal to −6.0 D 59 0.88(0.96)  64 0.88(1.00)  67 0.95(1.00)  
PVD   .79   .57   .42
Absent 131 0.90(1)  131 0.90(1)  131 0.93(1)  
Present 135 0.88(1)  135 0.88(1)  135 0.93(1)  
D = diopter; PVD = posterior vitreous detachment; SE = spherical equivalent; SG = standard gamble; TTO = time trade-off.

Utility Values and Acute-Onset Floaters
The mean (± SD) duration of presence of vitreous floaters was 54.8 ± 6.12 weeks, ranging from 1 week to 5 years and 10 months (300 weeks). Acute-onset floaters were noted in 142 of the 266 patients (53.4%). Patients with acute-onset floaters did not report significantly different utility values from patients with long-standing symptomatic floaters (TTO: acute-onset floaters = 0.88, long-standing floaters = 0.90, P = .34; SG [death]: acute-onset floaters = 0.89, long-standing floaters = 0.89, P = .90; SG [blindness]: acute-onset floaters = 0.93, long-standing floaters = 0.93, P = .81).

Utility Values and Bilateral Floaters
A history of bilateral vitreous floaters was present in 153 of 266 patients (57.5%). Patients with bilateral floaters did not demonstrate significantly different utility values from those having unilateral vitreous floaters (TTO: unilateral = 0.89, bilateral = 0.90, P = .89; SG [death]: unilateral = 0.89, bilateral = 0.89, P = .36; SG [blindness]: unilateral = 0.93, bilateral = 0.93, P = .75).

Utility Values and Myopia
The prevalence of myopia, defined as spherical equivalent greater than −0.5 D in at least 1 eye, in our study population was 60% (159/266), with a third (59/159, 37%) of these patients having high myopia. Utility values did not differ significantly with presence or absence of myopia in patients with vitreous floaters (TTO: myopia present = 0.90, myopia absent = 0.89, P = .55; SG [death]: myopia present = 0.86, myopia absent = 0.90, P = .26; SG [blindness]: myopia present = 0.91, myopia absent = 0.95, P = .92). The severity of myopia also did not show a significant relationship with utility values (TTO: myopia equal to or higher than −6.0 D = 0.88, myopia lower than −6.0 D = 0.90, P = .41; SG [death]: myopia equal to or higher than −6.0 D = 0.88, myopia lower than −6.0 D = 0.92, P = .35; SG [blindness]: myopia equal to or higher than −6.0 D = 0.95, myopia lower than −6.0 D = 0.94, P = .58).

Utility Values and Posterior Vitreous Detachment
A PVD was observed in 135 of 266 patients (50.7%). The presence of PVD did not affect utility values significantly (TTO: PVD present = 0.90, PVD absent = 0.88, P = .79; SG [death]: PVD present = 0.90, PVD absent = 0.88, P = .57; SG [blindness]: PVD present = 0.93, PVD absent = 0.93, P = .42).

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In this study, we assessed the health-related quality of life in 266 patients presenting primarily with a history of floaters using utility values. The results suggest that degenerative floaters have a negative impact on the health-related quality of life. Younger patients with symptomatic floaters exhibit relatively lower utility values for SG (blindness) when compared with elderly symptomatic patients.

Patients with floaters are willing to trade off an average 1.1 years out of every 10 years of their remaining life to get rid of the symptoms associated with floaters. Furthermore, these patients are willing to take, on average, an 11% risk of death and a 7% risk of blindness to get rid of symptoms relating to floaters. The mean utility values for patients with floaters are comparable to the utilities reported by patients with other eye diseases such as age-related macular degeneration, diabetic retinopathy, and myopia with similar visual acuity (visual acuity of 20/20 to 20/25) (Table 4). 9, 11, 12, 13, 14, 15 Interestingly, the mean TTO utility value for floaters is also comparable to TTO values reported for many other systemic diseases and health states such as hypertension, mild angina, mild stroke, colon cancer, and asymptomatic HIV infection (Table 5).8, 16, 17, 18, 19 Although floaters do not seem to affect quality of life to the same degree as more severe forms of ocular and systemic diseases, their impact is nevertheless noteworthy.

TABLE 4. Comparison of Utility Values for Symptomatic Degenerative Vitreous Floaters With Other Ocular Diseases and Health States
Ocular Disease/Health State TTO SG (Death) SG (Blindness)
Floaters 0.89 0.89 0.93
1. In teenage school students15 0.93 — 0.85
2. In medical students9 0.97 0.99 —
Glaucoma13 0.88 0.94 0.95
Diabetic retinopathy12 (BCVA 20/20 to 20/25) 0.85 0.88 —
Age-related macular degeneration11 (BCVA 20/20 to 20/25) 0.89 0.96 —
BCVA = best-corrected visual acuity in the better eye; SG = standard gamble; TTO = time trade-off.

TABLE 5. Comparison of Time Trade-off Utility Values for Symptomatic Degenerative Vitreous Floaters With Other Systemic Diseases
Systemic Disease/Health State TTO Utility
Floaters 0.89
Hypertension16 0.98
Mild angina8 0.87
Mild stroke17 0.87
Colon cancer18 0.88
Asymptomatic HIV infection19 0.87
HIV = human immunodeficiency virus; TTO = time trade-off.

Similar to other studies, we observed overall higher utility values for SG (blindness) when compared to the TTO and SG (death) values in our study population. This shows that compared to trading years of remaining life for a better health-related quality of life or taking a risk for immediate death, individuals are less willing to take a risk of blindness. This risk aversion with the SG technique has been reported by past studies investigating utility values in eye diseases.9

In our study population, younger patients (21–55 years) with symptomatic floaters were willing to take a relatively higher risk of blindness to get rid of floaters when compared with elderly patients (>55 years). Two previous studies have proposed that the higher utility values observed in teenage students (15-18 years) with myopia, in contrast with adults, suggests that students are less willing to take risks in return for perfect vision than adults because of differences in value of impact of the eye disease and life expectancy.15 Our finding suggests that younger patients, who belong to the economically active group, are more keen and less risk-averse to improve their health-related quality of life by opting for a therapeutic intervention to remove their floaters. This subgroup of patients may benefit from current treatment options to improve their health-related quality of life. The elderly symptomatic patients may have reported a relatively higher SG (blindness) utility value due to risk aversion when compared with younger patients.

We failed to observe a significant relationship between utility values and the socioeconomic variables. Results of previous studies that have investigated the relationship between socioeconomic variables and utility values in various eye diseases have been inconsistent. For instance, of the 4 studies that have examined the relationship between educational status and utility values in patients with eye diseases, 2 have failed to demonstrate a significant relationship between level of education and utility values.9, 11, 15, 18

We compared the utility values in patients with acute-onset floaters with those having long-standing floaters and did not find any significant difference in their utility values. This is similar to the findings of Brown and associates, which showed that duration of disease did not affect utility measurements in patients with age-related macular degeneration.11

Floaters are commonly reported in eyes with myopia. In our study, 59.7% of patients had myopia, with about a third of them having high myopia. Myopia itself is also known to affect quality of life.9, 15 Vitreous floaters are often perceived much earlier in myopic eyes as vitreous syneresis and PVD tends to occur at a younger age in these eyes.3, 4 The retinal magnification of the images associated with myopia also makes the symptom more pronounced. As myopia is a growing public health problem with high prevalence rates especially in several southeast Asian countries,5 the prevalence of patients with symptomatic floaters is likely to increase. This prompted us to compare the utility values associated with floaters in patients with and without myopia; however, we failed to demonstrate a significant relationship between utility values and presence (degree) of myopia in patients with floaters. Two previous studies have also shown no significant difference in utility values with different severity of myopia.9, 15

We are aware of certain potential limitations of our study. First, the results of this study may not truly reflect the impact of floaters on specific vision-related tasks because we did not use a vision-specific quality-of-life questionnaire. Second, we did not examine the relationship between utility values and detailed characteristics of vitreous floaters, such as number, size, and density of floaters as well as the area of visual field involved by the floaters. Other potential limitations that would preclude generalizing our study results are a relatively small sample size, a single-center study, and a predominantly Chinese study population.

In conclusion, symptomatic degenerative vitreous floaters have an impact on the health-related quality of life. Young symptomatic patients are more likely to take a risk of blindness to get rid of floaters.

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Publication of this article was funded by a National Healthcare Group – Small Investigator Grant, Singapore (NHG-SIG I/06/034). The funding organization had no role in the design and conduct of the research. The authors have no financial interests to disclose. Involved in design and conduct of the study (A.M.W., T.P.Y., K.G.A.E.); collection, management, analysis, and interpretation of the data (A.M.W., W.Y.L.); and preparation, review, or approval of the manuscript (A.M.W., W.Y.L., T.P.Y., K.N., K.G.A.E.). This study and the data accumulation were carried out with ethics approval from the Domain Specific Review Board of the National Healthcare Group, Singapore. Informed consent for the research was obtained from the patients. The study was conducted in adherence to the tenets of the Declaration of Helsinki and was HIPAA compliant.

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1.Mossa F, Delaney YM, Rosen PH, Rahman R. Floaterectomy: combined phacoemulsification and deep anterior vitrectomy. J Cataract Refract Surg. 2002;28(4):589–592
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2.Hikichi T, Trempe CL. Relationship between floaters, light flashes, or both, and complications of posterior vitreous detachment. Am J Ophthalmol. 1994;117(5):593–598
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3.Yonemoto J, Ideta H, Sasaki K, Hirose A, Oka C. The age of onset of posterior vitreous detachment. Graefes Arch Clin Exp Ophthalmol. 1994;232(2):67–70
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4.Byer NE. Natural history of posterior vitreous detachment with early management as the premier line of defense against retinal detachment. Ophthalmology. 1994;101(9):1503–1514
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5.Wong TY, Foster PJ, Hee J, et al. Prevalence and risk factors for refractive errors in adult Chinese in Singapore. Invest Ophthalmol Vis Sci. 2000;41(9):2486–2494
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6.Schiff WM, Chang S, Mandava N, Barile GR. Pars plana vitrectomy for persistent, visually significant vitreous opacities. Retina. 2000;20(6):591–596
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7.Torrance GW. Measurement of health state utilities for economic appraisal. J Health Econ. 1986;1:1–30
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8.Torrance GW, Feeny D. Utilities and quality-adjusted life years. Int J Technol Assess Health Care. 1989;5(4):559–575
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9.Lim WY, Saw SM, Singh MK, Au Eong KG. Utility values and myopia in medical students in Singapore. Clin Experiment Ophthalmol. 2005;33(6):598–603
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10.Brown MM, Brown GC, Sharma S, Garrett S. Evidence-based medicine, utilities, and quality of life. Curr Opin Ophthalmol. 1999;10(3):221–226
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11.Brown GC, Sharma S, Brown MM, Kistler J. Utility values and age-related macular degeneration. Arch Ophthalmol. 2000;118(1):47–51
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12.Brown MM, Brown GC, Sharma S, Shah G. Utility values and diabetic retinopathy. Am J Ophthalmol. 1999;128(3):324–330
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13.Saw SM, Gazzard G, Au Eong KG, Oen F, Seah S. Utility values in Singapore Chinese adults with primary open-angle glaucoma and primary angle-closure glaucoma. J Glaucoma. 2005;14(6):455–462
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14.Brown MM, Brown GC, Sharma S, Landy J. Quality of life and visual loss from diabetic retinopathy and age-related macular degeneration. Arch Ophthalmol. 2002;120(4):489–484
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15.Saw SM, Gazzard G, Au Eong KG, Koh D. Utility values and myopia in teenage school students. Br J Ophthalmol. 2003;87(3):341–345
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16.Stein JD, Brown GC, Brown MM, Sharma S, Hollands H, Stein HD. The quality of life of patients with hypertension. J Clin Hypertens. 2002;4:181–188
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17.Duncan PW, Lai SM, Keighley J. Defining post-stroke recovery: implications for design and interpretation of drug trials. Neuropharmacology. 2000;39(5):835–841
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18.Smith RD, Hall J, Gurney H, Harnett PR. A cost-utility approach to the use of 5-fluorouracil and levamisole as adjuvant therapy for Duke's C colonic cancer. Med J Aust. 1993;158(5):319–322
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19.Tsevat J, Solzan JG, Kuntz KM, et al. Health values of patients infected with HIV (Relationship to mental health and physical functioning). Med Care. 1996;34(1):44–57
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Ajeet M. Wagle is a Consultant Ophthalmologist at the Department of Ophthalmology & Visual Sciences at Khoo Teck Puat Hospital, Singapore. He specializes in the management of diseases of the vitreous and retina. Besides clincal work, he has keen interests in clinical research. He is a teaching faculty at the Faculty of Medicine, Yong Loo Lin School of Medicine, National University of Singapore and the Singapore Polytechnic Optometry Centre.

See Accompanying Editorial on page Dr. John Hagan's Blog

PII: S0002-9394(11)00064-X


© 2011 Elsevier Inc. All rights reserved.


Jul 14, 2011 - 25 comments

FROM: John C. Hagan III MD, FACS, FAAO   This is a reprint of an editorial in the July 2011 American Journal of Ophthalmology and represents the latest information on floaters. It references a second article from the same issue which I will also post.


In 1976, Dr Ernst Wynder, founding president of the American Health Foundation and founding editor of the journal Preventive Medicine, stated that “It should be the function of medicine to help people die young…as late in life as possible.”1 However, medicine in general, and ophthalmology in specific, are disease-oriented disciplines. In the former case, this is due to the fact that “Disease is a living experience for the man of flesh and bone. In contrast, health is a disembodied concept. It stimulates no emotional response because it is an inhuman, fleshless abstraction” (René Jules Dubos, The Silliman Lectures, Yale, 1965).1 As ophthalmologists, we are trained to evaluate eyes by seeking evidence of disease using biomicroscopy and ophthalmoscopy, as well as with diagnostic testing. When we rule out pathology by these modalities, we advise patients that they are free of disease. Such advice is apparently a frustrating and unfulfilling experience for patients with “floaters.” From their point of view, the consulting ophthalmologist who sought evidence of disease and found none has nonetheless failed to address their health and quality-of-life issues.

In youth, vitreous is a solid and clear gel filling the center of the eye, firmly attached to the retina. The exquisite transparency of vitreous allows unhindered transmission of light to the retina for photoreception.2 Other than “exogenous” sources, such as hemorrhage and inflammation, there are 2 main causes of the entopic phenomenon called “floaters,” which result from light scattering by structures within the vitreous body and/or at the posterior vitreous cortex. Although devoid of liquid during infancy, the vitreous body begins to liquefy in childhood due to molecular rearrangement of the constituent macromolecules hyaluronan and collagen. Part of this molecular alteration involves cross-linking and aggregation of vitreous collagen fibrils. If advanced, fibrillar aggregation can cause sufficient interference of photon transmission to induce chronic and progressive floaters. In myopia, the process of vitreous gel liquefaction and fibrillar aggregation appears to be accelerated, a manifestation of myopic vitreopathy.3

Concurrent with vitreous gel liquefaction, there is weakening of vitreoretinal adhesion. When both processes advance in tandem to a critical threshold,2, 3 there is separation of the posterior vitreous cortex from the retina, perhaps initially only in the perifoveal region.4 Displacement of liquefied vitreous into the developing cleavage plane between the posterior vitreous cortex and the internal limiting lamina of the retina collapses the posterior vitreous away from the retina, an event called posterior vitreous detachment (PVD). While it has long been taught that PVD is abnormal, it may well be that PVD is the salubrious result of evolutionary progress. This concept arises from the growing awareness that in a variety of diseases, such as diabetic retinopathy5 and age-related macular degeneration6, 7 (AMD), PVD is a far safer condition. That notwithstanding, entopic phenomena resulting from this event induce acute floaters. These arise from the posterior vitreous cortex itself as well as tissue that is sometimes adherent to the posterior vitreous cortex, typically parapapillary fibro-glial in origin. When attributable to myopic vitreopathy,3 PVD occurs 10 to 15 years earlier in life.

The subjective experience of sudden floaters is very common after PVD. While many patients complain that this is bothersome, ophthalmologists tend to pay little heed to these symptoms other than to rule out anomalous PVD3, 8 manifesting as either peripheral or posterior retinal pathology. Once the absence of disease has been assured, the typical eye care professional ceases to be concerned about the issue of floaters. While the Hippocratic principle of “primum non nocere” has guided our approach to date, it may well be time to reexamine our perception that floaters are simply an innocuous, indeed curiously desirable, manifestation of the “normal” aging process.

In this issue of the Journal, Wagle and associates9 present fascinating new information concerning the utility value of floaters, as expressed by patients. Utility values allow an objective quantification of the functional quality of life associated with a specific “disease” state. A utility value of 1.0 implies a perfect “health” state, while death has a utility value of 0.0. The findings of this study indicate that the utility values of floaters are equal to AMD and lower than diabetic retinopathy and glaucoma. According to this study, floaters have lower utility values than mild angina, mild stroke, colon cancer, and asymptomatic HIV infection. This indicates that floaters have a significant negative impact on the quality of life as compared to ocular as well as systemic diseases. It is interesting to note that there was no difference between acute (less than 1 month) and chronic (mean duration of more than 1 year) floaters. This finding throws into question our long-held belief and oft-offered counsel to patients that their symptoms will lessen in severity, either due to settling of vitreous opacities below the optical axis or because of neuro-psychological adaptation. Surprisingly, the investigators claimed that 49.3% of the study group had no PVD. This is suspect, since subjects only underwent an examination and not diagnostic testing, such as ultrasound or optical coherence tomography. Furthermore, 56% of the subjects were women and 59.7% were myopic—both known to predispose to PVD. On the other hand, the authors appropriately point out that the retinal magnification of the images associated with myopia can make floaters seem more pronounced, perhaps explaining how a large number of subjects in this study complained of floaters in the absence of a PVD.

Most remarkably, the investigators of this study found that these patients were willing to take an 11% risk of death and a 7% risk of blindness to get rid of symptoms related to floaters. As the authors state, patients with floaters are willing to trade off 1.1 years out of every 10 years of their remaining lives to get rid of the symptoms of floaters. To some extent that explains the willingness of patients to undergo unproven attempts at mitigating their symptoms, such as YAG laser vitreolysis, for which there is no evidence of efficacy. Definitive treatment is available with vitrectomy, which has been rendered faster, less invasive, and safer by the advent of 25G instrumentation. Yet, there are small risks associated with this invasive procedure and in phakic patients there are lens-related considerations. To obviate the cost and risk (albeit small) of surgery, the future will likely see the development of drug therapy for floaters, via pharmacologic vitreolysis.10 Caution must be exercised, however, for some agents may induce or aggravate floaters as opposed to dissolve them.10, 11

Future advances in our ability to promote health and not just treat disease will depend upon a paradigm shift in philosophy and the development of technologies for health evaluation. We should first accept health as its own diagnosis1 and not just the absence of disease. Improving our understanding and management of conditions such as age-related vitreous degeneration,2, 3 diabetic vitreopathy,12 and myopic vitreopathy3 will then depend upon developing new diagnostic nanotechnologies, such as dynamic light scattering (DLS). This noninvasive, laser-based nano-detector is able to quantitate particle sizes in the cornea, lens, aqueous, and vitreous13 as small as 3 nm in diameter. DLS has been used to determine an alpha-crystallin index in 380 lenses of human eyes14 as well as demonstrate the effects of diabetic vitreopathy11 and pharmacologic vitreolysis.15, 16 In the meantime, however, we need to be aware of and sensitive to the fact that there continues to be a proliferation of floater websites on the internet and the formation of international floater organizations, as expressions of patient frustration with our inability or unwillingness to help them die young, as late in life as possible.

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The author indicates no funding support. The author has been a consultant to Pfizer, Shire, Storz, Alcon, ISTA, Vitreo-Retinal Technologies, and ThromboGenics, and is a shareholder in ThromboGenics, Ltd. The author (J.S.) is solely responsible for the conceptualization of this article; collection, management, analysis, and interpretation of data; and preparation, review, and approval of the manuscript.

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1.Sebag J. The diagnosis of health (First Prize, National Essay Competition). Preventive Medicine. 1979;8(1):76–78
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A graduate of Columbia & Harvard, Jerry Sebag is considered a leading authority on vitreous. He is Founding Director of the VMR Institute in Huntington Beach, California (www.VMRinstitute.com), Professor of Clinical Ophthalmology at the Doheny Eye Institute of USC, Fellow of the American College of Surgeons, and Fellow of the Royal College of Ophthalmologists (United Kingdom). In 2005, Dr. Sebag was inducted into the American Ophthalmological Society, and in 2010 he was designated a Fellow of ARVO.