Article Type : Research Article
Volume : 5
Issue : 2
Online ISSN : 2395-1451
Print ISSN : 2395-1443
Article First Page : 142
Article End Page : 145
Primary open angle Glaucoma (POAG) is a chronic, progressive optic neuropathy caused by a group of ocular conditions which lead to damage of the optic nerve with loss of visual function. Various modalities are available to detect the damage to the optic nerve head and the retinal nerve fibre layer. Traditionally Visual Evoked Potentials (VEP) has been used to test optic nerve and Humphrey Visual Field Analyser with results favouring one over the other. Hence a study was conducted comparing parameters of standard VEP with the indices of Humphrey Visual Field Analyser in patients of POAG.
Material and Methods: A group of 30 diagnosed cases of primary open angle glaucoma. Selected patients were then taken up for Visual Field Analysis and VEP recordings using VEP systems as per the protocol of International society for clinical electrophysiology of vision (ISCEV). Visual field analysis was performed on Humphrey Visual Field Analyser II – series. Patient’s pupil size was noted and the test selected was central 30-2.
Results: Patients belonged to the age group of 50-54 years. About 2/3 of patients were males & about 1/3 of patients were females. Of the 60 eyes 34 eyes (56.6%) had delayed P100 latency whereas 26 eyes (43.4%) showed GHT outside normal limits. Mean of MD was more (3.54) when the GHT was the deranged parameter and less when the deranged parameter was P100 latency (2.63).
Conclusion: VEP is affected in POAG. As an independent parameter more eyes had delayed P100 values when compared to GHT. In 16/60 eyes (26.6%) the P100 latencies were affected before GHT changes in Humphrey visual fields. In this study P100 latencies were statistically significant when compared to MD & GHT index of Humphrey Perimeter.
Keywords: Glaucoma hemifield test, Humphrey visual field analysis, Primary open angle glaucoma, P100 latency, Visual evoked potentials.