Confocal Scanning Laser Ophthalmoscopy in High Myopic Eyes in a Population-Based Setting

Abstract

To compare the parameters of confocal scanning laser ophthalmoscopy (Heidelberg Retina Tomograph [HRT] II; Heidelberg Engineering, Heidelberg, Germany) in high myopia with those in age-matched emmetropia. A population-based study in which HRT II data were analyzed from 135 healthy subjects with high myopia (spherical equivalent [SE] from -6 to -12 D) and 135 age-matched subjects with emmetropia (SE from -1 to +1 D). The HRT parameters, the correlation between disc area and ovality, and asymmetry between the right and left eyes were evaluated. High myopia was associated with greater disc ovality, smaller cup areas and cup volumes, higher rim volumes, height variation contour (HVC), and the mean retinal nerve fiber layer (RNFL) thickness compared with those parameters in emmetropia (P < or = 0.003). The intergroup differences in the rim volume and mean RNFL thickness remained significant (P = 0.003) after adjustment for the disc area and ovality. The disc area was correlated significantly (P < or = 0.002) with most parameters in both groups. The disc ovality was significantly (P = 0.005) negatively correlated with the disc area only in high myopia and significantly (P < or = 0.003) positively correlated with the rim volume, HVC, and mean RNFL thickness in both groups. Asymmetry of the mean RNFL thickness was significantly (P = 0.003) greater in high myopia than in emmetropia. The characteristics of the HRT parameters in highly myopic eyes involved smaller cup parameters and greater rim and RNFL parameters compared with emmetropic eyes. The effects of disc area and ovality on the HRT parameters in highly myopic eyes differed from those in emmetropic eyes.