Objective: To investigate the morphologic alterations at or around the blood vessels of the retinal vascular arcade by optical coherence tomography (OCT) in highly myopic eyes.
Design: Observational case series.
Participants: Two hundred eighty-seven eyes of 149 patients with high myopia (refractive error >/=-8.00 diopters [D] or axial length >26.5 mm) were studied. Fifty-six emmetropic (+1.00 to -1.00 D) eyes and 44 eyes with low (<-6.00 D) myopia were examined as controls.
Methods: The participants had a complete ophthalmologic examination, including stereoscopic fundus observations and OCT examinations. Multiple OCT scans were made along the entire extent of the posterior vascular arcade and across the fovea in each patient.
Main outcome measures: The incidence of paravascular retinal cysts, vascular microfolds, and paravascular retinal holes was determined. Retinoschisis at the retinal vessels and a macular retinoschisis were also evaluated.
Results: In 287 eyes with high myopia, paravascular retinal cysts were detected in 142 eyes (49.5%), vascular microfolds in 128 eyes (44.6%), and paravascular retinal holes in 77 eyes (26.8%) by OCT. The paravascular retinal holes were partial-thickness lamellar holes in all of the patients; full-thickness holes were never detected. Vascular microfolds and paravascular lamellar holes were always accompanied by paravascular retinal cysts. Optical coherence tomography examinations revealed the presence of vitreoretinal traction on the inner walls of retinal cysts in sections adjacent to the retinal holes. In the 77 eyes with paravascular lamellar holes, 34 eyes (44.2%) were associated with internal limiting membrane (ILM) detachments and 15 eyes (19.5%) were associated with a macular retinoschisis. In fact, 15 of 18 eyes (83.3%) with a macular retinoschisis had paravascular lamellar holes. None of the 100 control eyes had these paravascular abnormalities.
Conclusions: These findings indicate that different types of paravascular abnormalities are relatively common in highly myopic eyes. Our findings suggest that paravascular lamellar holes form when the inner wall of paravascular retinal cysts is avulsed by vitreous traction. The presence of paravascular lamellar holes might enhance the proliferative response of the ILM, and this might be an important causative factor for the development of a macular retinoschisis in highly myopic eyes.