Functional vision with cataracts of different morphologies: comparative study.

PURPOSE

To evaluate the influence of cataract morphology on the functional vision of patients with age-related cataract and normal macular function and compare subjectively perceived functional impairments to distance visual acuity, reading acuity, and maximum reading speed between cataract types.

SETTING

Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.

METHODS

Seventy-five patients awaiting first-eye cataract surgery were asked to characterize their visual difficulties in everyday life using a German version of the VF-14 questionnaire. Cataracts were categorized and graded using the Lens Opacities Classification System III. Monocular and binocular visual acuity and reading performance were determined in randomized order.

RESULTS

There were significant differences in functional vision between nuclear cataracts and posterior subcapsular cataracts (PSC); the VF-14 score and the self-reported visual satisfaction were significantly lower in PSC patients (P<.05). Posterior subcapsular cataracts significantly increased self-reported impairment in distance and near vision, although the visual acuity was comparable to that in the other groups (P =.9). Significant differences in functional vision were also seen between PSC and nuclear-cortical cataracts (P<.05). No significant differences in functional vision were found between nuclear cataracts and nuclear-cortical cataracts (P>.05).

CONCLUSIONS

The VF-14 questionnaire reliably evaluated functional differences caused by different cataract morphologies; these differences were underestimated when only visual acuity was measured. Patients with PSC had increased functional impairment, indicating that cataract surgical intervention is indicated at an earlier stage in these patients. The significant differences between the morphological types of cataract should be taken into consideration when the benefit of cataract surgery is to be measured on the basis of functional improvement.