Association Between Extrafoveal Paravascular Retinoschisis and Central Retinal Vessel Trunk Dragging in High Myopia

To assess occurrence and associations of myopic extrafoveal paravascular retinoschisis (EPR).

Using optical coherence tomographic images of the optic disc and macula, taken in the population-based Beijing Eye Study, we assessed prevalence and associations of parapapillary retinoschisis.

The study included 3336 individuals (3336 eyes) with a mean age of 64.2 ± 9.6 years (range, 50-93) and a mean axial length of 23.4 ± 1.2 mm (range, 20.16-30.88). EPR prevalence (34/3336, 1.0%; 95% confidence interval [CI], 0.6-1.4) increased from 1/3046 (0.03%) to 8/173 (4.6%; 95% CI, 1-8), 4/74 (5.4%; 95% CI, 0-11), 10/25 (40%; 95% CI, 19-61), and 11/18 (61%; 95% CI, 36-86) with axial lengths of ≤25.0 mm, 25.01 to 26.0 mm, 26.01 to 27.0 mm, 27.01 to 28.0 mm, and >28.0 mm, respectively. Higher EPR prevalence was associated (multivariable analysis) with higher prevalence of central retinal vessel trunk dragging (CRVTD) (odds ratio [OR] = 8.81; 95% CI, 3.02-25.7; P < 0.001) and longer axial length (OR = 2.97; 95% CI, 2.27-3.89; P < 0.001; Nagelkerke R2 = 0.55), or alternatively with longer fovea-optic disc center distance (OR = 2.79; 95% CI, 1.55-5.03; P < 0.001). In a nonlinear manner, EPR prevalence increased steeply beyond an axial length of 25.5 mm and a fovea-disc center distance of 5.5 mm. These relationships were complemented by univariate associations between EPR prevalence and temporal retinal vessel straightening, smaller angle kappa, higher myopic macular degeneration stage and prevalence, and larger parapapillary beta zone and gamma zone.

EPR was a common feature in eyes with severe/high axial myopia and was mainly associated with CRVTD and longer axial length or fovea-disc center distance. As a hypothesis, EPR, contrary to myopic foveoschisis, may be due to a stretching of the temporal large retinal vessels in highly myopic eyes, related to the fovea-disc distance elongation.