INTEROCULAR ASYMMETRY IN CHOROIDAL THICKNESS AND RETINAL SENSITIVITY IN HIGH MYOPIA

To investigate the normal range of interocular asymmetry in choroidal thickness and retinal sensitivity in high myopia without ocular fundus manifestations and to determine the relationship between interocular asymmetry and refractive error.

Forty-three patients (35.07 ± 13.31 years) with high myopia and 45 healthy participants (39.9 ± 14.1 years) were administered an ocular coherence tomography and a microperimetry examination to determine choroidal thickness and retinal sensitivity at the foveal region and at 1, 2, and 3 mm, nasally, temporally, superiorly, and inferiorly. Absolute interocular differences were calculated to determine the normal range of asymmetry, in 95% confidence intervals.

The choroid was thinner in the myopic group at all explored locations (all P < 0.05), with larger absolute interocular differences in most of the choroidal locations under evaluation (all P < 0.05). Similarly, retinal sensitivity was reduced in the myopic group, although statistically significant differences were only encountered at the subfoveal location (P = 0.001). Retinal sensitivity asymmetry was found to increase with refractive error.

The expanded range of choroidal thickness and retinal sensitivity asymmetry found in high myopia in the absence of disease is of relevance when exploring these patients for early signs of ocular pathology.