General EYE ADVICE

Correction of Presbyopia

Most people who have never worn glasses previously will begin to wear glasses for presbyopia between their mid-forties to early fifties. Those people who were always able to see both at distance and near with a single-powered lens, now find that their glasses do not help them equally as well at all distances. Bifocal lenses can be used to enable both distance and near vision, however lately there is an increasing trend to use progressively-powered lenses. These lenses avoid the necessity for a dividing line within them and also allow for focusing at intermediate or arm's length distances.

Several authors have documented a phenomenon of age-related astigmatic changes which is observed in patients who have presbyopia. It is my own belief when presbyopes (without proper correction) force their eyes to focus on objects at close distances, the eyes tend to undergo certain changes in their form or shape. One such change is a certain type of astigmatism of the so-called "against-the-rule" (ATR) type.

When glasses are then prescribed for presbyopia, or any other refractive error incorporating this astigmatic correction, patients may complain of eyestrain symptoms when using their glasses. This is especially noted when patients wear glasses for the first time, but can also happen when patients renew their glasses. To avoid this common problem, it is advisable to avoid the unnecessary straining of the eyes at near which occurs when a middle-aged or older person fails to wear the proper presbyopic or reading correction. Otherwise, it can be very difficult to achieve clear vision without difficulties in adjusting to a new prescription. See ATR ASTGMATISM in part II (A) for detailed discussion of this condition.

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