Influence of the Extent of Myopia on the Progression of Normal-Tension Glaucoma

To evaluate the influence of the extent of myopia on the progression rate of normal-tension glaucoma (NTG).Retrospective, observational case series.One hundred forty-three eyes of 143 patients with NTG who were treated from 1994 through 2006 and followed up with standard automated perimetry were evaluated in this study. The participants were divided into 4 groups: mild myopia (-0.76 to -2.99 diopters [D]), moderate myopia (-3 to -5.99 D), severe myopia (-6 D or less), and nonmyopia (emmetropia and hyperopia, -0.75 D or more) groups. The change in mean deviation, corrected pattern standard deviation, mean thresholds of 10 zones corresponding to the glaucoma hemifield test, and thresholds of 52 points of the nonmyopia group were compared with those of the other myopia groups. Additionally, we controlled each analysis for age and posttherapeutic intraocular pressure to preclude the possibility of these covariates influencing the analysis of the effect of myopia on the progression of glaucoma.There was no statistically significant difference between the nonmyopia group and each of the myopia groups in terms of mean deviation, corrected pattern standard deviation, mean thresholds of 10 zones corresponding to the glaucoma hemifield test, and the thresholds of 52 point changes against refraction. Moreover, with the control of the other covariates (age and posttherapeutic intraocular pressure), no statistically significant differences were noted (multivariate analysis using mixed model, P > .1).Although a high incidence of open-angle glaucoma among myopic patients has been reported previously, myopia did not influence the progression rate of NTG after treatment.