Abstract
Purpose: :
Bilateral surgery for age related cataract, undertaken as a staged procedure, will inevitably result in a period in which one eye has poorer acuity than the other. We investigate the magnitude of this inter–ocular difference in acuity, the time between procedures and the effect this degraded binocularity may have on a patient’s lifestyle.
Methods: :
We present sample data from within a multi–centre, multi–national prospective study of endophthalmitis prophylaxis. We show that, due to monocular cataract and monocular pseudo–phakia, individuals may be forced to live with an inter–ocular visual acuity difference for long periods of time. Acuity has been measured in each eye pre–operatively and in the operated eye post–operatively using standard clinical methods, and then converted to a LogMAR equivalent.
Results: :
A random sample of 23 patients from the first centre in this on–going study show a mean inter–ocular acuity difference of 0.42+0.24 logMAR (1 SD) immediately after first eye surgery, increasing to 0.52+0.30 logMAR (1 SD) just prior to second eye surgery. For a period between 52 and 485 days (mean 332 +119) these patients had to cope with an inter–ocular acuity difference equivalent to 3–4 lines of Snellen. Under these conditions everyday viewing and hence lifestyle may be compromised.
Conclusions: :
Questionnaire studies have validated the need for second eye surgery, but we investigate the effect that compromised binocularity between first and second eye surgery may have on quality of life. Monocular cataract can cause binocular inhibition and intermittent disabling glare, leading to degraded acuity and contrast sensitivity. The Pulfrich phenomenon, inappropriate motion perception, has been demonstrated in patients with monocular cataract. Instability and deficits in fine visuo–motor control have been associated with low grade binocular function. We discuss the implications of this delay before second eye surgery for this elderly population, particularly its effect on everyday activities such as personal mobility and driving.
Keywords: binocular vision/stereopsis • cataract • quality of life