Contrast sensitivity function and photostress recovery time in glaucoma suspects.

Abstract

OBJECTIVE: The aim of this study was to assess contrast sensitivity function and photostress recovery time in Glaucoma suspects and to find the association of raised IOP with Contrast sensitivity function (CSF) and Photostress recovery time (PSRT).

METHODS: In this cross sectional observational study, 97 glaucoma suspects were included. The suspects were selected from regular
visitors of the outpatient department of Ophthalmology Mayo Hospital Lahore. The ethics board of the University approved the study
protocol. The principles of Declaration of Helsinki were followed in the study. All the subjects provided written informed consent. CS was measured monocularly using the Pelli-Robson chart at distance of 1 m with standard room illumination and scores were noted for at least two letters identified by the suspects with least contrast. PSRT was tested using distant direct ophthalmoscope. One sample t-test was used to analyze the data and compare means of CSF and PSRT with normal values mentioned in literature. Pearson correlation was applied to find the relation of variables.

RESULTS: The analysis included 97 glaucoma suspects. Mean age was 49.98 ± 7.12 years, and 41% were men. Mean CSF was 0.92 ±0.10
(p<0.000). Similarly, PSRT was 59.32seconds (p<0.000). The correlation of IOP with CSF was r= -0.435(p<0.000) and IOP with PSRT was r =
0.224 (p=0.028).

CONCLUSION: The study results showed that Contrast sensitivity is reduced and Photostress recovery time is delayed in glaucoma suspects. The raised IOP also showed significant association with CSF and PSRT. This result is a useful psychophysical indicator and could give an important clinical understanding of the early changes before glaucomatous optic disc and defected visual field are appeared.

KEY WORDS: Glaucoma, Glaucoma suspects, Contrast sensitivity.