The Effect of Cataract on Spatial and Temporal Contrast Sensitivity Tests in Glaucoma

Purpose: To investigate the efficacy of spatial and temporal contrast sensitivity (CS) tests for detecting early glaucoma in the presence of cataractMethods: Twenty-seven early glaucoma patients (mean age 60 ±10.2 years) with early cataractous signs were selected together with twenty-seven control subjects matched for age and cataract type. Cataracts were graded using the grading scheme of Casser et al (1997). Measurements of grating spatial and temporal CS at 20 HZ in central vision were performed in each group for spatial frequencies (SF) 0.5, 1.5 and 3 c/d with and without glare. Visual acuity, visual fields sensitivity measurements and structural tests using Heidelberg Retina Tomograph (HRT) were also performed. Results: Overall reduction in both spatial and temporal CS at all SF was found for glaucoma patients compared with cataract patients with a significant mean difference of 0.2 log units (p <0.01).. This difference correlated well with measurements of visual fields or HRT parameters. The effect of the glare on CS was significant (p <0.01) and was similar for both groups. A significant correlation (p<0.05) was found between the glare factor and the glaucomatous damage assessed by HRT. Conclusions: Our results indicate that both spatial and temporal CS tests can distinguish glaucomatous vision loss from vision loss resulting from cataracts, the temporal test providing better separation at higher SF. The CS reduction due to the presence of glare increased with the glaucomatous damage, suggesting an increase of intraocular straylight in glaucoma. References: 1. Casser L. Fingeret M. and Woodcome T. Atlas of Primary Eyecare Procedures ed.2, 1997.