Why do Multifocal lenses after cataract surgery cost more but result in poorer vision for both short and long distances when compared to Monofocal lenses?Cataracts Eye Health
There are several aspects to consider in answering this question.
Firstly, there is no cure for presbyopia/'Lao Hua', which refers to the loss of autofocusing ability of the eye. There are no cures, there are only compromises. That is why, in order to get relatively good vision for far and near, some compromises have to be made for the contrast at a particular distance when compared to monofocal lenses.
But then again, you have to consider what you mean by 'poorer'.
If you have a patient with a monofocal lens set at emmetropia (distance vision), then the vision is very blurred at near without glasses. While a patient with a multifocal lens will see pretty clearly at near without glasses.
Therefore when you say that '...result in poorer vision for both short and long distances when compared to monofocal lenses' you have to qualify that by specifying whether it is with or without glasses.
In other words, depending on how you look at it, multifocal lenses do not necessarily result in poorer vision. Especially when you are comparing patients who do not wear glasses.
For the other part of this question regarding cost, engineering multifocal capability into a lens requires research and extra precision steps in manufacturing. This is in addition to the usual steps in obtaining regulatory approval.
As such, it is not surprising that a multifocal lens would cost more than a monofocal lens.
The ultimate questions to be answered for a particular patient really have to do with
- How much he or she values spectacle freedom (even if there are halos and a reduction in contrast), vis a vis
- How much he or she values absolute contrast/clarity (even if there is a need to wear glasses).
Dr Por Yong Ming
MBBS, FRCSEd, FRCS, MRCOphth, MMed
38 IRRAWADDY ROAD
#09 - 26/27/28/29 Singapore 329563
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