Retinal and Choroidal Thickness in Patients with High Myopia without Maculopathy

Objective: To evaluate macular choroidal thickness (CT) and retinal thickness in Turkish patients with high myopia without maculopathy and in normal subjects and to examine the association with age, axial length (AL), best corrected visual acuity (BCVA), cycloplegic refraction, and spherical equivalent (SE).

Methods: This prospective study was performed between January 2015 and June 2016 in the Department of Ophthalmology, Duzce University Medical Faculty. It had 65 individuals (30 patients with high myopia, 35 healthy subjects). Retinal and choroidal images were obtained using spectral-domain optical coherence tomography (OCT). Measurements (one subfoveal, three temporal, three nasal) were taken at 500 μm intervals up to 1,500 μm using the caliper system. Only the right eye was used for subsequent analysis.

Results: The mean age was 29.5 ± 14.5 years and 25.6 ± 7.0 in the high myopia and control groups, respectively. The subfoveal CT was significantly lower in the high myopia group (mean, 218.3 ± 102.25 mm) than the control group (mean, 331.83 ± 99.06 mm; p < 0.001). In both groups, the choroid was thinnest at the nasal 1,500 μm location, being 158.40 ± 90.8 μm and 301 ± 103.59 μm, respectively. Retinal thickness in both groups was thickest at the nasal 1,500 μm location and thinnest in the subfoveal region. In patients with high myopia, CT was negatively correlated with AL (r=-0.490, p=0.006) and age (r=-0.455, p=0.012).

Conclusions: Highly myopic eyes have a thinner choroid, which may be secondary to longer AL but is not an independent factor. Further studies in the field of OCT are important to exploring the pathology of high myopia.