A clinical study of primary open angle glaucoma (POAG) in myopia-An observational study

Abstract

The Primary open-angle glaucoma is the most common type of glaucoma causing irreversible blindness. Myopia is one of the risk factor responsible for pathogenesis of glaucoma. The association between myopia and primary open angle glaucoma has been found in numerous case studies. The aim of the study to evaluate the relationship of myopia in primary open-angle glaucoma by classifying the eyes into low, moderate and high myopia.This prospective study was performed on 1414 axial myopic patients more > 18 years. Clinical examination included, slit-lamp biomicriscopy, Goldman applanation tonometry, refraction, dilated optic disc assessment, central corneal thickness, visual field analysis and optical coherence tonography.Out of 1414 patients, 769(54.38%) were male and 645(45.62%) were female. Low myopia (<-3D) cases are 938(66.32%), moderate myopia (-3D to -D) 309(21.88%), high myopia (>-6D), 107(11.8%). Maximum number of cases were in younger age group (20-30 years). Intraoccular Pressure > 21mmHg in 143 cases of low myopia, 78 cases in moderate myopia, 72 cases in high myopia. There were 138 cases with glaucomatous field changes. Out of 138 cases 86(62.32%) were high myopia, 35(25.36%) were moderate myopia and 17(10.8%) cases were low myopia. The CUP-DISC ratio <0.5 in 75.95% cases, 0.5-<0.9 in 20.37% cases, >0.9 in 3.68% cases. The average values of circumpapilary Nerve Fiber Layer thickness in micrometer of low myopia, moderate myopia, high myopia, with non-glaucomatous cases were 98.9, 97.3, 93.5 and with glaucomatous cases, 74.4, 73.7 and 73.3 respectively. The average values of Ganglion Cell Complex thickness in micrometer in low, moderate and high myopia without glaucoma were 94.9, 93.5, 92.7 and with glaucoma 77.3, 74.6, 70.2 respectively. This study shows there is strong relationship between myopia and primary open-angle glaucoma. Early detection of glaucoma in myopic patients is necessary in delaying blindness.