Correlation Between VEP Latency, CDR and PSD On Standard Automated Perimetry In Newly Diagnosed POAG Cases

Aim and Objective:- The current study was conducted to find out the correlation between Pattern reversal VEP (visual evoked potential) parameters, standard automated perimeter parameters and cup disc ratio (CDR) in newly diagnosed cases of POAG (primary open angle glaucoma). Materials and Methods:- The study included 72 individuals of both the genders. The subjects underwent routine ophthalmic examination of anterior and posterior segment, IOP (intraocular pressure) measurement, visual field testing by Humphery’s automated perimeter and Pattern reversal VEP (visual evoked potential) testing. The subjects were classified into mild, moderate and severe based on MD (Mean deviation). Results:- In our study, the mean PSD (pattern standard deviation) and CDR (cup disc ratio) value increased with increase in the severity of glaucoma. The findings of our study also showed that increased PSD and CDR mirrored with increase in P100, N75 and N145 latency and decrease in P100 amplitude. The PSD was positively correlated with the latencies of VEP and negatively correlated with the amplitude of VEP waves (p<0.001). Conclusion:- We conclude that VEP can be used as a reliable tool for monitoring the progression of glaucoma. cupping of optic nerve head with presence of open angles and absence of any secondary cause of raised IOP. 2,3 Visual evoked potential (VEP) is an important diagnostic tool that can be used to study the optic nerve head and visual field changes in cases of POAG. Increased latencies and decreased amplitude of VEP both have been documented in cases of glaucoma. 4 The results of the previous studies show a statistically significant correlation between magnitude of change in VEP parameters and PSD on automated static perimetry. The above correlation suggests slowing of neural conduction from retina to the visual cortex in the brain. It also supports the reliability of the usage of VEP test in cases of glaucoma. Researchers suggest that the glaucomatous visual field defect could be attributed to damage of the retinal ganglion cells and their axons. VEP test is compatible with the functions of retinal ganglion cells so it provides specific information. Visual field testing does not selectively reveal the structures of visual pathway involved in the etiopathogenesis of glaucoma. 5 The current goal of treatment of glaucoma patients is neuroprotection. The neuroprotective drugs can help in survival of nonfunctional retinal ganglion cells that are still alive. VEP testing can be used as a diagnostic tool to detect these abnormal nonfunctional retinal ganglion cells and monitor the effect of neuroprotective treatment. 6 The latency of response of retinal ganglion cells is the indicator of their health which can be studied by VEP. 7,8 As currently existing glaucoma detecting techniques are Abstract non-specific, costly, time consuming and subjective in nature so ophthalmologists are always in search of specific and reliable low cost technique. VEP can be used as a potential tool for early diagnosis and follow up of cases of glaucoma. The present study was conducted to find out the correlation between Pattern reversal VEP parameters, standard automated perimeter parameters and cup disc ratio in newly diagnosed cases of POAG as : Baisakhiya S, Goyal GL, Garg P, Khan Z. Correlation Between VEP Latency, CDR and PSD On Standard Automated Perimetry In Newly Diagnosed POAG Cases.