Asymmetric choroidal vascular pattern in tilted disc syndrome

To observe the choroidal vasculature in patients with tilted disc syndrome (TDS) using en face optical coherence tomography (OCT) and to evaluate the symmetry of the choroidal vascular pattern in the macular area.

En face OCT was performed using a Plex Elite 9000 (Zeiss) with a 12 × 12 mm image of the macula, which was flattened with retinal pigment epithelium and segmented into choroidal layers. The middle/large choroidal vessels were evaluated for vertical symmetry qualitatively by the retina specialist coauthors and quantitatively by binarization analysis of choroidal vessel density and mean vessel diameter.

The 2 cases and 4 eyes (19.0%) that were difficult to segment due to the severe slope of the macular area were excluded. Of the 17 eyes in the remaining 13 cases, asymmetric middle/large choroidal vessels were observed in all eyes. Vessel density (P = 0.01) and mean vessel diameter (P < 0.01) of the choroidal middle/large vessels were significantly higher in the superior than in the inferior choroidal segmentation. Serous retinal detachment was observed in 4 eyes, all asymmetric cases.

Vertical asymmetry of the middle and large choroidal vessels is observed in most TDS patients. Circulatory imbalance due to choroidal vascular abnormalities in TDS may be one of the causes of serous retinal detachment.

What is known: Tilted disc syndrome is the congenital disease with ocular morphologic abnormalities associated with incomplete closure of the embryonic fissure of the eye at the inferior optic nerve head  Vertical cross-sectional optical coherence tomography images revealed that the choroid above the macula in tilted disc syndrome is relatively thickened, whereas the choroid within the inferior staphyloma is thinning.

Evaluation of choroidal vascularity in tilted disc syndrome by en face optical coherence tomography revealed qualitatively and quantitatively highly dense choroidal vessels in the superior region, with larger diameter choroidal vessels than in the inferior region, and vertical asymmetry with an upward predominance.  Choroidal circulatory imbalance due to vertical asymmetry of the choroidal vessels may be one of the causes of serous retinal detachment in tilted disc syndrome.