English

Abstract

AIM OF THE STUDY: To analyse Disc Damage likelihood ratio in patients with established open angle glaucoma and to correlate it with field defects and to thereby obtain an anatomical versus functional correlation. This study also evaluates the diagnostic ability of disc damage likelihood scale in glaucoma. MATERIALS AND METHODS: 50 cases of established open angle glaucoma were included in this study. Patients more than 45 yrs, BCVA more than 6/36, with open angles were included. Other causes of optic neuropathy, angle closures, BCVA less than 6/36, patients operated less than a year were excluded. All of the cases underwent detailed anterior segment examination, fundus examination. Visual fields were recorded by Octopus 301 using G1 program and TOP strategy. After field testing, DDLS scores were calculated after dilataion with tropicamide. The DDLS score and field parameters of the patients were analysed. RESULTS: Of the 50 patients included in this study, 30% were in the age group of 45-50 yrs and 24% were aged more than 66 years. 62% were male patients and 38% were female patients. 70% were on topical antiglaucoma medications and 30% had undergone trabeculectomy. The average vertical disc diameter was 1.86 mm. Among the 50 patients, 4 patients had asymmetry of disc diameter between the right and left eye. The cup disc ratio in all four patients showed significant asymmetry, of more than 0.2. But the DDLS score in both the eyes in all four patients were the same. DDLS score and average loss variance showed a strong positive correlation as the r value was 0.95. CONCLUSION: Disc diameter evaluation is an important part of optic nerve head evaluation. In cases with asymmetry of the cup disc ratio between two eyes, asymmetry of the disc size should also be considered if the neuroretinal rim is healthy. Disc Damage Likelihood Scale (DDLS) is a better indicator of optic nerve head status and has strong positive correlation with visual field indices.