Prevalence of Pathological Myopia and Its Association with Ocular Disorders

Abstract

Introduction: Pathological myopia (PM) is defined as the presence of structural changes due to axial elongation in eyes with high myopia. Numerous vision-threatening conditions are known to be more prevalent in eyes with pathological myopia including retinal detachment, myopic retinoschisis, macular holes, choroidal neovascularization, and chorioretinal atrophy. These pathological changes often lead to progressive loss of vision. Present study was conducted to find out the burden of pathological myopia and its associated factors at a tertiary care centre. Materials and Methods: A hospital based cross sectional study was conducted including a sample size of 345 with at least -5.0 D spherical equivalent of myopia in both eyes. Each subject was interviewed followed by extensive ophthalmologic screening examination, including measurements of visual acuity and fundus examination by Direct & Indirect Ophthalmoscopy. Data was analysed using SPSS ver. 21.0 using appropriate statistical tests. Results: Prevalence of pathological myopia among myopia cases between 7 to 40 years old was 9%. Among 31 cases of pathological myopia, juvenile and youth onset was seen in 29% cases each while early adult onset was seen in 41.9% cases. Prevalence was more in females (12.4%) as compared to males (5.7%). Low visual acuity, high spherical/ cylindrical error and high intra-ocular pressure were significantly associated with pathological myopia. Mean axis length in both right and left eye was significantly more in cases with pathological myopia (p<0.05). Conclusion: Around one in ten myopia cases suffers from pathological myopia. Pathological myopia is more common in males especially during adulthood and is associated with poor visual acuity and axial elongation. Another important finding observed in present study was presence of raised intra-ocular pressure among high myopic cases which can be a risk factor for development of optic neuropathy.