Structural and functional macular inter-ocular asymmetry in patients with high myopia

Resum

BACKGROUND: Retinal evaluation performed in the optometry clinic allows optometrists to track the prognosis of retinal disease and to assess anatomical and functional changes related to age and pathological and non-pathological conditions. OBJECTIVES: The purpose of this research was to investigate the normal range of inter-ocular asymmetry in retinal and choroidal thickness and in retinal sensitivity high myopia without ocular fundus manifestations and to determine the relationship between inter-ocular asymmetry and refractive error. METHODS: 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 retinal and choroidal thickness and retinal sensitivity at the foveal region and at 1, 2 and 3 mm, nasally, temporally, superiorly and inferiorly. Absolute inter-ocular differences were calculated to determine the normal range of asymmetry, in 95% confidence intervals. RESULTS: The choroid was thinner in the myopic group at all explored locations (all p < 0.05), with larger absolute inter­ ocular 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). Retinar sensitivity asymmetry was found to increase with refractive error. CONCLUSION: The expanded range of retinal and choroidal thickness, as well as 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.