Photoreceptor inner/outer segment defect imaging by spectral domain OCT and visual prognosis after macular hole surgery

Purpose. To evaluate photoreceptor inner/outer segment (IS/OS) defect parameters by using spectral domain-optical coherence tomography (SD-OCT) for correlation with visual outcomes in macular hole surgery (MHS). Methods. This study was an interventional, retrospective case series. Twenty-three eyes (23 patients) were examined by SD-OCT before and after (median, 2.3 months) anatomically successful MHS. Two formats of OCT were analyzed: linear (raster) and composite (partial fundus image). Factors that may have confounded IS/OS measurements were controlled by using weighting and normalization of data. The main outcome measures were diameter and area of the IS/OS defect, weighted area of the IS/OS defect, macular density ratio (MDR), healing pattern of the macular hole, and preoperative and postoperative best corrected visual acuity (BCVA). Results. Poorer preoperative BCVA correlated with larger preoperative diameter of the IS/OS defect (P = 0.005). A greater improvement in BCVA correlated with a larger preoperative area of IS/OS defect (P = 0.038) and smaller MDR (P = 0.012). Poorer postoperative BCVA correlated with a larger postoperative diameter of the IS/OS defect (P = 0.010), larger weighted postoperative area of IS/OS defect calculated by raster scan (P = 0.013), larger postoperative area of IS/OS defect measured from the partial fundus image (P = 0.003), and apparent glial sealing pattern on SD-OCT (P = 0.0005). The shape of the IS/OS defect area was round and regular before surgery, but irregular afterward. Conclusions. BCVA after MHS correlates with objectively ascertainable SD-OCT measurements of IS/OS defects and other features. The postoperative area of the IS/OS defect, when directly measured, correlates more strongly with BCVA than do linear-based measurements, perhaps because of the irregular shape of the IS/OS defect after surgery.