Clinical Profile of Myopic Patients as a Risk Factor for Primary Open Angle Glaucoma - A Prospective Observational Study in Gorakhpur, Uttar Pradesh

BACKGROUND Myopia is a complex trait including both genetic and environmental factors as well as gene-environment interactions. It has been recognized as a risk factor for development of glaucoma. Both Myopia and raised IOP are known to increase mechanical stress at optic nerve head leading to glaucomatous nerve damage. This study intends to evaluate the clinical profile of myopic subjects and its correlation with Primary open angle glaucoma (POAG). METHODS A prospective observational study done from November 2019 to December 2020 after taking proper informed consent and ethical clearance. 164 eyes of 96 patients studied were divided into three groups, Group 1: low myopia (< -3.00D), Group 2: moderate myopia (-3.00 D to -5.75 D), Group 3: high myopia (≥ -6.00 D). A complete ocular examination was performed. Intraocular pressure was measured using Goldmann applanation tonometer. Visual field analysis using Humphrey automated perimetry was done in patients with suspected primary open angle glaucoma (POAG). Angle parameters and central corneal thickness (CCT) were measured using anterior segment optical coherence tomography (AS-OCT). RESULTS 164 eyes of 96 Myopic subjects were studied with no dropout during study period. Mean age was 46.05 yr. (range: 25-75 yr.). The refraction ranged from -0.50 DS to -17.00 DS. There was no statistically significant difference between Intraocular pressure (IOP), Central corneal thickness (CCT), corrected IOP and Nasal and Temporal Trabecular-iris Angle (TIA) between male and female of same age group. Mean IOP and mean CCT were found to vary significantly with age and with higher degree of myopia. Corrected IOP, Nasal and Temporal TIA increase significantly with higher degree of myopia. Cup-disc ratio (CDR) was found to be significantly higher in patients with moderate to high degree of Myopia. CONCLUSIONS Myopia is an important risk factor for development of primary open angle glaucoma, with its incidence increasing in patients with moderate to high myopia. KEYWORDS Myopia, Primary Open Angle Glaucoma, Intraocular Pressure, Central Corneal Thickness, Trabecular Iris Angle