Oct 31, 2016
IOL Dysphotopsias: Defining, Describing and Dealing with in Clinic
John F. Doane, MD Discover Vision Centers Refractive News Fall 2016 (Dr. Doane is one of this country's finest refractive/cataract/cornea surgeons and a frequent featured speaker at eye meetings world wide)
Mr. Murphy who coined Murphy’s Law was probably thinking of intraocular lens dysphotopsia complaints when he was developing his treatise on human endeavor – “ Anything that can go wrong – will. “ What a smart-alike!! With minor joking aside the affected patient with IOL related dysphotpsias can suffer significant visual morbidity and psychological anguish . I hope in this issue of the Discover Vision Centers’ Refractive Newsletter to share insights on diagnosing, defining and managing patients as effectively as one can that experience unwanted visual symptoms from their elective intraocular lens implant.
Modern phacoemulsification with implantation of an intraocular lens is a marvel of human endeavor yet not perfect. Just think what our world would be like if this were not the case. Cataract remains the leading cause of blindness in the undeveloped world. Medical practitioners likely take for granted the incredible impacts we have on patients’ lives. Think about some of the crazy things that have been status quo in our lives or are still status quo in some regions of the world. What about couching of the crystalline lens? It is certainly barbaric by today’s First World standards. The incidence of vision loss and possible complete blindness is appalling. Another issue is the resulting poor vision as most patients do not have spectacles or contact lenses to remedy the aphakic state. I remind myself of my grandfather’s cataract surgery. He was born in 1895 and had ‘ elective ‘ cataract removal without IOL implantation in the 1960’s. His visual restoration? Thick aphakic spectacles with marked pin-cushion distortion. Yikes. The process took an advancement when aphakic contacts were an alternate option to aphakic spectacles. In my career I have had a few patients walk-in wearing aphakic spectacles or contact lenses and some of these we have moved to secondary IOL implantation after several decades of aphakic spectacles and contacts. These are rare occurrences in the 21st Century fortunately for all involved. With state-of-the-art IOL implantation, as we have discussed previously, we are now trying to hit the ball out-of the-park with toric IOL’s, monovision and presbyopia correcting IOL’s to minimize or completely eliminate corrective lens wear. Yet, we have one unexpected side effect of modern IOL design – dysphotopias.
Dysphotopsias after IOL implanation are aberrant optical phenomena that interfere with vision. There are two distinct types of dysphotopsias: positive and negative. Positive dysphotopsias are “ light “ phenomenon and include rainbows, streaks, crescents, rings, halos,veiling glare, haze and fog. Negative dysphotopsias are dark phenomenon and are defined as relative and absolute scotomas. The negative dysphotopsia – temporal dark crescent – is the most common dysphotopsia I encounter with patients. It may be as common as 10 percent of all patients in the first days to weeks after IOL implantation. To date I feel Jack Holladay has described this best in his 2012 article on the topic. 1 The temporal dark arc represents a unique type of scotoma named a penumbra. Positive dysphotopsias in my experience are much less common but inherently easier to understand and explain to patients.
Halos are most frequent with multifocal or ringed IOL’s and are directly related to the lens design. They can also be seen with monfocal IOL’s at night if there is residual spherical refractive error. Halos are not noted during the day but only at night from point sources of light. Crescents and rings are caused by optic decentration and or tilt. Waxy vision I believe is best put in the positive dysphotopsia grouping and is seen with multifocal IOL’s and is related to contrast sensitivity mismatch between what the IOL provides and the patient’s perception.
On postoperative day one patients will typically describe the following two symptoms if any to me. They will note the temporal crescent negative dysphotopsia. They may note that they also see a shimmering effect. I have attributed the latter to either mild movement or shaking of the IOL within the capsular bag or to patient physical movement. The latter symptom in my experience is transient and as the capsule shrink wraps around the IOL it resolves. .
If a patient has received a multifocal IOL at some point they may note “ waxy vision “ in the first month. When I hear this I am very concerned as this rarely if ever completely goes away and usually remains problematic. Patients state that “ yes, I can see small print but everything has soft edges as if wax paper is over the letter “.
If a patient had ocular trauma before or after IOL implantation the symptoms of a decentered optical system come into play as mentioned above including crescents, streaks and rings. These are acutely disconcerting and not tolerated by patients.
An essential part of managing a patient who has a dysphotpsia complaint is to not minimize the report, brush them aside and convey they or their complaint is “ crazy “. I have seen several patients in consultation that were referred on the brink of suicide. These extreme cases have involved multifocal dysphotopsias. Some of these patients have come from several states away and had been told by their surgeon or other surgeons that “ nothing can be done or live with it “. It has been my experience that all of these patients can be completely cured of their symptoms or markedly improved. The first step is to tell the patient “ I believe your symptom(s) are real “ and “ let us find the cause and create a solution either with me or someone I know “.
The great news about temporal cresent dysphotopsia is that if you tell patients “ I know exactly what you are describing. It is uncommon not to notice it early and the good news is resolves for almost everyone. Holladay states that ~ 2% of patients may still notice this at 1 year postoperatively. I have yet to operate on a patient due to temporal arc dysphotopsia from a penumbra scotoma. Multifocal waxy vision “ dysphotopsia “ is another issue. I tell patients that who are considering a multifocal IOL that 1-2% of these IOL’s will have to be exchanged due to intolerable “ waxy vision “. 98+% of these patients do not notice this symptom and do great. The remainder after IOL exchange are immensely grateful. The key point with this complaint is that if it is noted do not be tempted to recommend or perform a posterior capsulotomy. This makes an IOL exchange a riskier proposition ( retinal detachment / cystoid macular edema ) and limits IOL possibilities. For decentered IOL’s they simply have to be remedied be it centering with iris or scleral fixation, anterior chamber IOL or IOL exchangeX. Lastly, if any of the positive dysphotopsias in scotopic conditions are related to residual refractive error or could be remedied with pupillary constriction by all means prescribe night driving glasses or trial Alphagan p for these patients.
With proper diagnosis, timely intervention most, if not all, of the visual morbidity from dysphotposias can be resolved and a patient can be happy and productive.
1. Holladay JT, Zhao H, Reisin CR. Negative dysphotopsia: The enigmatic penumbra. J Cataract Refract Surg 2012; 38:1251-65.