The influence of sensory deprivation on binocular vision after bilateral cataract extraction with intraocular lens implantation

Purpose: Cataract extraction with intraocular lens implantation is one of the most frequent surgical procedures. However, benefits associated with the surgery may be restricted by binocular vision disorders. The purpose of the study is to evaluate binocular function of vision in patients after bilateral cataract extraction in relation to the length of period between surgeries.

Material and methods: The study included 50 patients operated twice, due to bilateral cataract. All patients were examined

six weeks after the second surgery and divided into three groups according to the operational interval (<12 months, 12–24

months, >24 months). Presence of asthenopic symptoms, distance and near squint angle, fusional amplitudes , stereopsis and

convergence were evaluated.

Results: Asthenopic symptoms were present respectively in 8% (n = 1), 42% (n = 8), 37% (n = 7) of patients in groups 1, 2

and 3. Exophoria was found in 16.6% (n = 2) of cases in the first group, 17.5% (n = 3) in the second group and 31.6% (n = 6)

in the third group. There was no significant difference in average prismatic fusional vergence range between groups and a negative correlation between amblyoscopic fusional convergence and the period between surgeries was found. Mean stereopsis

was 76.7 ± 62.1; 89.5 ± 66,2; 76.8 ± 66.7 seconds of arc in subsequent groups. Average convergence was: 6.8 ± 6.9 cm

in the first group, 7.1 ± 3.9 cm in the second group and 7.5 ± 5.0 cm in the third group.

Conclusions: There are significant differences in binocular vision parameters in patients after bilateral cataract extraction in relation to the period between surgeries. The prolongation of this time was connected with increased number of patients complaining to asthenopic symptoms, with exophoria and reduced amblyoscopic fusional convergence.