Lack of association between localized cataract and visual field loss: the Blue Mountains Eye Study

To examine whether localized cataract is related to localized field defects on suprathreshold visual field testing.

Suprathreshold screening visual fields (Humphrey 76-point test) and lens photographs, graded using the Wisconsin System, were performed on participants attending the Blue Mountains Eye Study, which examined 3654 subjects residing in an area west of Sydney, NSW, Australia. The results for 2276 subjects were analysed in the present study.

There were no significant relationships between total points missing in the visual field and the degree of cortical, posterior subcapsular (PSC) or nuclear cataract after adjusting for confounders (test for trend P = 0.9, 0.7 and 0.9, respectively). Adjusted prevalence ratios and 95% confidence limits for the association between 10 or more points missing and the presence of cataract were 0.94 (0.77-1.25) for cortical, 1.26 (0.82-1.93) for PSC and 1.06 (0.86-1.30) for nuclear cataract. Similarly, there was no relationship between the presence of cortical or PSC cataract and sectoral visual field loss in any quadrant or hemifield.

Neither cortical, nuclear nor PSC cataracts increase the total points missing on the 76-point suprathreshold field test. Similarly, neither cortical nor PSC cataracts cause sectoral visual field loss on this screening field test. In the presence of cataract, sectoral visual field loss on non-thresholding visual field screeners must be attributed to other causes, such as glaucoma. The present study provides a clinical alert that localized field loss is unlikely to be related to cataract.