A study on association between intraocular pressure and myopia

Background: Myopia is one of the commonest ocular disorders and has been recognized as a risk factor for glaucoma. Aim of this study is to find the association between intraocular pressure (IOP) and different grades of myopia from low to high and compare it with emmetropia.Methods: Observational study done from January to May 2014. 178 eyes of 100 patients were divided into four groups according to their refractive status. Group 0 – Emmetropia (+0.5 to -0.5D), Group1- low myopia (-0.75 to -3.00D), Group 2 -moderate myopia (-3.00 to -5.00D) and Group 3 - high Myopia (>-5.00D).A complete ocular examination was done. Intraocular pressure was measured by standard Goldmann applanation tonometer.Results: Mean age of patients was 30.09 (range 11-47 years). The refraction ranged from +0.50D to -9.00D. Group 0 (emmetropia) included 84 eyes and mean IOP was 12.75 (SD: 2.18).Group 1 included 74 eyes with a mean IOP of 12.32 (SD: 2.44),Group 2 had 14 eyes with a mean IOP of 15.00 (SD:2.25)and Group 3 had 6 eyes with a mean I0P 18.5 (SD:0.7).There was no statistically significant difference in IOP between low myopic and emmetropic patients but the IOP in moderate and severe myopia was higher compared to emmetropic patients. Conclusions: There is statistically significant correlation (p<0.05) between IOP and myopia, in moderate and high myopia groups. The IOP was higher in those groups than in emmetropia and low myopia thereby increasing the risk of glaucoma in these patients.