Why a prescription can remain after cataract surgery
The implant's power is calculated from measurements of the eye's length and corneal curvature. The calculation is very accurate in most eyes, but it is less predictable in eyes that have had LASIK, PRK or RK, in very long or very short eyes, and in eyes with irregular corneas. Astigmatism that was not corrected with a toric lens also remains. And occasionally the eye simply heals with the lens sitting slightly differently than planned. The result is a residual prescription: vision that is better than before but not as sharp without glasses as it could be.
Option one: a laser touch-up
For small residual prescriptions and astigmatism, LASIK or PRK on the cornea is the simplest correction. The eye has to be stable, usually two to three months after cataract surgery, and the cornea has to be healthy and thick enough. This is a common way to fine tune a cataract result, and it is quick to recover from.
Option two: exchanging the implant
For a larger error, or when a patient wants a different type of lens, for example to move from a monofocal to a multifocal, the implant can be exchanged. This is best done in the first months after surgery, before the lens becomes fixed in the capsule. It is a more involved procedure than a touch-up and is recommended when the laser cannot correct the amount of error.
Option three: a piggyback lens
A thin secondary lens can be placed in front of the original implant to add the missing power without removing anything. It suits eyes where an exchange would be risky and the error is too large for the cornea. Whether it fits your eye is decided at the evaluation.
Preventing the problem: the Light Adjustable Lens
For patients who have not yet had cataract surgery and whose measurements are hard to predict, especially after previous LASIK or RK, the Light Adjustable Lens avoids the issue. Its power is fine tuned with light treatments after surgery, once the eye has healed, so the residual prescription is corrected in the lens itself rather than afterward.
Cataract surgery done elsewhere
If your cataract surgery was done at another practice, we can still evaluate it. Bring your operative report if you have it, which gives the lens model and power; if not, the evaluation measures everything needed. A full examination confirms the eye is healthy and stable, measures the residual prescription and the cornea, and leads to a plain recommendation.
Is this right for your eyes?
Nothing on this page is a diagnosis. Whether this is the right choice for you is decided by a full examination at one of our 4 offices: Pasadena, Huntington Beach, Woodland Hills and Beverly Hills.
About this content: This page was written with the assistance of AI tools and reviewed for medical accuracy by Dr. Bavand Youssefzadeh, DO. It is general information, not medical advice, and does not replace an eye examination. Individual results vary. Read our medical disclaimer.
