There is no universal time to do cataract surgery. The cardinal rule is that when the person is unable to do the things they need to do (drive at night, read, see clearly for TV, movies, perform their work) and the things they very much enjoy doing (crafts, hunting, shooting, sports, taking trips, going to friends and church at night) and the cataract is the only problem or the main problem then surgery is indicated provided the person understands the risks and the alternative of not having surgery. (In some cases there are risks to understand of NOT having surgery such as the cataract getting to hard [increases the risk of surgery], too 'ripe' [rare in the US but a big problem in so called third world countries requires emergency surgery], not being able to pass a drivers license, pilot's license, commercial driving license, increase risk of falls and disorientation in the elderly.
If there are other problems in the eye such as macular degeneration, glaucoma, diabetic retinopathy or maculopathy, amblyopia, etc. the problems will still be present after the surgery and will affect the final result. When groups of people that have had cataract surgery get together and talk about their results the variation in the final results are usually not due to complications but that those with poor vision post operatively have other problems in their eye that the cataract surgery did not, as was not expected to help.
Having said the above a commercial pilot, over the road trucker, a person that works at night, taxi drivers, etc will need cataract surgery at a relatively early stage to do their work safely and meet their job requirements. A person in their late 80's to early 90's that doesn't drive, doesn't read, rarely goes out of their house, that has multiple other physical or mental problems will likely not be bothered by a relatively large cataract and the best course of action may be to leave that 'big' cataract alone.
With your high myopia your vision was likely never a crisp 20/20 and never will be even with successful cataract surgery due to the myopic macular degeneration---something that can worsen with time. You are also at an increased risk of retinal detachment. (please see previous postings on vitreous detachment, retinal detachment, flashes/floaters/curtain & veils) on the ophthalmology website, the eyecare patient forum, use the 'search feature' on the site.
Cataract surgery, even successful small incision surgery increases the risk of retinal detachment by as much as 5-10 times normal. (rough estimates 1 in 3-4 thousand for people not having had cataract surgery and no major risk factors to 1 in 500 or even less after umcomplicated surgery). Your risk without cataract surgery can be as high as 1 in 200 to 1 in 500. After cataract surgery your risk may be as high as 2-3%.
Provided you understand these risks you would be a candidate for cataract surgery anytime your feel it is a major problem as outlined above and your eye surgeon agrees.
This is what I do in my highly myopic patients that are considering or have decided to have cataract surgery.
1. I give them detailed 'informed consent'
2. I sent them to a retinal specialist for a second opinion abour cataract surgery and a special detailed examination of the retinal looking for holes, tears, thin areas, vitreous traction, existing small retinal detachments. If these are present the retinal specialist will often use laser or a freezing treatment to bolster or strengthen these areas.
3. The surgery is done using several special techniques that lower the risk of surgery in the highly myopic.
4. I see the person more often than my regular patients. The myopic patient knows the symptoms of a possible retinal detachment (flashes, sudden increase of floaters, loss of peripheral vision). I instruct the patient on 'finger counting visual fields' and have them check their peripheral vision at home daily.
5. At one week and 6 weeks the patient sees the retinal specialist to repeat the special examinination of the retina looking for new problems--if present they are treated.
I believe that is the information your need. If your vision is a big problem (not a small or medium size problem) and the cataract is the main reason and you have confidence in your surgeon and the surgeon agrees that surgery would be beneficial (BUT NO SURGERY IS EVERY RISK FREE) then you may want to proceed with the surgery.. (the risks are much, much less now than say 10-15 years ago due to better techniques). Because of your age (young) your will in all likelihood need cataract surgery sometime.
Good luck.
JCH MD
Thank you for your very informative response. I appreciate your time in preparing a response.
A related discussion, Cataract Surgery for -21 + -24 myopia was started.