Decreased parafoveal photoreceptor, choroidal thickness seen in high myopia

Eur J Ophthalmol. 2011; doi:10.5301/ejo.5000092.

Choroidal thickness and photoreceptor layer thickness in the parafoveal region may decrease significantly in patients with high myopia, a study found.

The study analyzed Spectralis (Heidelberg Engineering) optical coherence tomography scans of 64 eyes divided into three refractive groups: normal sight, mild or moderate myopia, and high myopia.

OCT findings showed no significant differences between the normal and mild-to-moderate myopia groups. However, compared with the normal sight group, the high myopia group exhibited significantly reduced parafoveal photoreceptor layer thickness, parafoveal retinal thickness and choroidal thickness (P < .05). Univariate and forward multivariate linear regression analysis showed obvious intertwining of parafoveal photoreceptor layer thickness and choroidal thickness.

"We hypothesize that choroid and photoreceptors form the [neuron vascular unit]; the change in any component in the unit will affect the other components," the study authors said.

The researchers noted that further analysis is warranted. Clear visualization of the choroid-sclera borderline was not obtained for all eyes. Because mean age was low in all three groups, it was not included in the forward multivariate linear regression analysis.