The path to presbyopia: straight or crooked?

The non-linear trends in the mean amplitude of accommodation with age that are observed in transverse studies as presbyopia is approached can be explained in terms of the summated effect of many individual linear trends. Increases in the near addition that may be required by patients after their early fifties are probably associated with an age-dependent decrease in acuity, which necessitates a closer working distance to increase angular subtense, rather than with any continuing decline in accommodation.