Ocular Axial Length and Its Associations in an Adult Population of Central Rural India: The Central India Eye and Medical Study

Purpose: To investigate the normal distribution of axial length of the globe, which is a major measurement of the eye, and its associations with other ocular and systemic parameters. Design: Population-based study. Participants: The Central India Eye and Medical Study is a population-based study performed in a rural region of central India. The study comprised 4711 subjects (aged 30+ years) of 5885 eligible individuals (response rate, 80.1%). Methods: A detailed ophthalmic and medical examination was performed. The axial length was measured sonographically. Main Outcome Measures: Axial length. Results: Axial length measurements were available on 4698 study participants (99.7%). Their mean age was 49.4 +/- 13.4 years (range, 30-100 years), and the mean refractive error was -0.18 +/- 1.48 diopters (range, -20.0 to +7.25 diopters). Mean axial length was 22.6 +/- 0.91 mm (range, 18.22-34.20 mm). In multivariate analysis, axial length was significantly (P < 0.001) associated with the systemic parameters of increased age, taller body height, greater body mass index, and higher level of education, and with the ocular parameters of lower best-corrected visual acuity, lower corneal refractive power, deeper anterior chamber, thicker lens, and more myopic spherical power and cylindrical refractive power. Within the highly myopic group, as defined by an axial length that exceeded 26.5 mm, none of these associations (except for the association between axial length and spherical refractive power) were statistically significant (P > 0.15) in univariate or multivariate analysis. Conclusions: In a rural population of central India, the mean ocular axial length was 22.6 +/- 0.91 mm, which was shorter than that of other populations. Axial length was associated with the systemic parameters of increased age, taller body height, greater body mass index, and a higher level of education, and with the ocular parameters of lower best-corrected visual acuity, lower corneal refractive power, deeper anterior chamber, thicker lens, and more myopic spherical and cylindrical refractive power. These associations were valid only for those eyes that were not highly myopic, whereas axial length was associated with refractive error only in highly myopic eyes. Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references. Ophthalmology 2010; 117: 1360-1366 (C) 2010 by the American Academy of Ophthalmology.