[Macular choroidal thickness assessment with SD-OCT in high myopia with or without choroidal neovascularization]

To measure macular choroidal thickness (CT) using spectral-domain optical coherence tomography (SD-OCT) in eyes with myopic macular choroidal neovascularization (CNV), and to compare choroidal thickness in these eyes with highly myopic eyes without CNV.

Sixty-four eyes with myopic CNV matched with 64 highly myopic eyes without CNV by age and axial length (AL) were examined between January 2010 and November 2011. OCT scans were performed with spectral-domain OCT (TOPCON OCT 2000). The reference position was changed from the vitreous to the choroid. OCT scan patterns consisted of seven sections; the subfoveal CT was measured manually between Bruch's membrane and the internal portion of the sclera in eyes with CNV and from the pigment epithelium to the scleral interface in eyes without CNV.

In the subgroup with CNV, the mean subfoveal CT was 51.71 μm ± 17.35. A statistically significant negative correlation was found between CT and AL (r=-0.615, P=0.0001). Regression analysis demonstrated a decrease of 8.4 μm per mm of AL. In the subgroup without CNV, matched with the CNV subgroup by age (P=0.597), and AL (P=0.813), the mean subfoveal CT was 93.35 μm ± 34.81 μm. The difference between the two subgroups was statistically significant (P<10(-4)).

Macular choroidal thickness is reduced in high myopia, especially when complicated by CNV. It has not yet been shown that choroidal thinning may be a risk factor for choroidal neovascularization, but our results may suggest that macular choroidal thinning may lead to hypoxic retinal changes resulting in secretion of VEGF and thus CNV.

Macular choroidal thinning observed in high myopia with CNV. These findings may suggest that choroidal changes may play a role in the pathogenesis of choroidal neovascularization.