Determination of macular hole size in relation to individual variabilities of fovea morphology

To determine the preoperative anatomic factors in macular holes and their correlation to hole closure.

Forty-six eyes with consecutive unilateral macular hole who had undergone surgery and followed up for at least 6 months were enrolled. Optical coherence tomography images and best-corrected visual acuity (BCVA) within 2 weeks prior to operation and 6 months after surgery were analyzed. The maximal hole dimension, foveal degeneration factors (inner nuclear layer cysts, outer segment (OS) shortening) and the widest foveolar floor size of the fellow eyes were measured. For overcoming preoperative individual variability of foveal morphology, an 'adjusted' hole size parameter (the ratio between the hole size and the fellow eye foveolar floor size) was used based on the fact that both eyes were morphologically symmetrical.

Mean preoperative BCVA (logMAR) was 1.03±0.43 and the mean postoperative BCVA was 0.50±0.38 at 6 months. Preoperative BCVA is significantly associated with postoperative BCVA (P=0.0002). The average hole diameter was 448.9±196.8 μm and the average fellow eye foveolar floor size was 461.3±128.4 μm. There was a correlation between hole diameter and the size of the fellow eye foveolar floor (Pearson's coefficient=0.608, P<0.0001). The adjusted hole size parameter was 0.979±0.358 (0.761-2.336), which was a strong predictor for both anatomic (P=0.0281) and visual (P=0.0016) outcome.

When determining the extent of preoperative hole size, we have to take into consideration the foveal morphologic variations among individuals. Hole size may be related to the original foveal shape, especially in relation to the centrifugal retraction of the foveal tissues.