Correlation between Length of Foveal Cone Outer Segment Tips Line Defect and Visual Acuity after Macular Hole Closure

Abstract

To determine whether the postoperative length of the photoreceptor cone outer segment tips (COST) line defect is significantly correlated with best-corrected visual acuity (BCVA) after macular hole closure. Retrospective, consecutive, observational case series. Fifty-one eyes of 51 patients with a surgically closed macular hole were studied. Spectral-domain optical coherence tomography (SD-OCT) was used to obtain images of the foveal area, and the lengths of the COST line defect were measured in the images obtained 1, 3, 6, 9, and 12 months after macular hole surgery. The correlation between the length of COST line defect and the BCVA was determined. The lengths of the COST line defect, the inner segment/outer segment (IS/OS) junction defect, the external limiting membrane (ELM) line defect in the SD-OCT images, and the BCVA. The COST line defect was gradually restored centripetally 1 to 12 months postoperatively. The length of the COST line defect was significantly correlated with the BCVA at 1, 3, 6, 9, and 12 months postoperatively (P < 0.001). Forward stepwise regression analyses showed that the postoperative BCVA was significantly correlated with the length of the COST line defect (P < 0.001) but not with that of the IS/OS junction and ELM line defects after 6 months. The preoperative length of the COST line defect was significantly correlated with postoperative BCVA at 12 months (P = 0.020), but the length of the IS/OS junction and ELM line defects was not. The preoperative length of the COST line defect was significantly longer than the fluid cuff diameter of the macular hole (P = 0.020), indicating that the influence of the elevated neurosensory retina at the fluid cuff on the SD-OCT signals of the COST line was probably minimal. The postoperative BCVA at 12 months can be calculated by the following regression equation: BCVA = 0.00020 × (length of preoperative COST line defect [μm]) - 0.23 (F value = 15.4; P < 0.001). The recovery of the foveal COST line defect is related to visual recovery after macular hole closure. The length of the preoperative COST line defect may predict the BCVA after macular hole surgery.