When I was a second-year optometry student, an older clinic instructor told us if he could pick any prescription for himself, he would choose 0.75 D myopia. This made no sense to us, as we were learning how to refract to give the best distance acuity. He just smiled and said, “You’ll understand some day.” There’s nothing like presbyopia to make his point. Having perfect distance vision has real limitations as you age, and there’s no group that typifies this more than pseudophakes.
The patients who are least dependent on glasses, as they reach their 70s, are the low myopes. So, why do most cataract surgeons choose implants that correct distance vision to plano? Since nearly all pseudophakes will require glasses of some sort after surgery, what is the best post-op refractive outcome that will allow them to have the most freedom from glasses for daily activities?
When I refer patients for cataract surgery, I routinely recommend my patients have a post-op refraction of -0.75 D. With this prescription, they can see their alarm clocks and mirrors in their bathrooms in the morning. They can cook food, see their cell phones, watch TV, even drive a car without a restriction on their driver’s licenses. They can interact with their families and see their computers pretty well without glasses. These day-to-day activities matter most to the typical elderly patient.
On the other hand, if they were plano at distance, they would be tied to their glasses for most of the day. It doesn’t help them to have 20/20 uncorrected distance vision while driving, if they can’t see their dashboards.
- When patients have previously worn monovision contact lenses, they are a natural fit for monovision IOLs. This rather small segment of cataract surgery referrals are the most independent of eyewear following cataract extraction. Occasionally, we recommend adding driving glasses for these patients to improve night driving or viewing movies.
- When a patient is a 2.00 D to 3.00 D myope, it is important he understands what will be lost at near with plano at distance. I often recommend that these patients consider remaining -2.00 D and keep their vision where they are comfortable.
- Patients who have successfully worn RGP or soft multifocal contact lenses often do well with multifocal IOLs. However, they need to be counseled that they still will need occasional reading glasses.
I REST MY CASE
I submit to you that a large segment of cataract patients would benefit most from low amounts of myopia as opposed to fully correcting their distance vision. This addresses most of their indoor activities and will give them the greatest amount of freedom in their day-to-day activities. OM