[Optical coherence tomography predictive factors for idiopathic macular hole surgery outcome]

Abstract

Objective: To evaluate the use of preoperative optical coherence tomography (OCT) image and some related indexes as predictive factors for the visual outcomes of the idiopathic macular hole (IMH) after pars plana vitrectomy and the internal limiting membrane (ILM) peeling surgery.

Methods: This was a case-series study. Twenty-five eyes of 23 IMH patients undergoing a successful vitrectomy and ILM peeling surgery and following up more than 6 months were included in this retrospective study. Of the 23 patients, 6 were male and 17 were female. The median patient age was 67-year old (range 63 to 71 years). The median duration of IMH was 6 months (range 3.5 to 12.0 months).In the patients, the macular hole was found in 9 eyes at stage II, 11 eyes at stage III, and 5 eyes at stage IV. Best corrected visual acuity (BCVA) were examined before and after the surgery. The minimum diameter (a) , the height (b) and the base diameter (c) of macular holes were measured by OCT. According to the indexes, macular hole index (MHI, b/c) , tractional hole index (THI, b/a) , diameter hole index (DHI, a/c) were calculated, respectively. Spearman rank correlation analysis was performed to understand the correlations between postoperative BCVA and the related indexes. Cut-off values were obtained for MHI and THI, respectively, from receiver operating characteristic (ROC) curve analysis.

Results: The median preoperative BCVA was 0.100(range 0.050 to 0.180). The median MHI, THI and DHI was 0.476(range 0.416 to 0.684), 1.048(range 0.761 to 1.346) and 0.536(range 0.431 to 0.645), respectively. The median 3-month postoperative BCVA was 0.150 (range 0.120 to 0.275), markedly improved after surgery (Mann-Whitney U test:P = 0.002) . The median latest postoperative BCVA was 0.250 (range 0.135 to 0.350), also markedly improved (Mann-Whitney U test, P = 0.002) . MHI, THI and preoperative BCVA correlated significantly with postoperative BCVA by Spearman rank correlation analysis (rMHI = 0.481, P = 0.015; rTHI= 0.516, P = 0.008; preoperative BCVA = 0.560, P = 0.004, respectively). Areas under the curve of 0.740 and 0.760 for MHI and THI were obtained respectively. Cut-off values of 0.475 and 0.973 were obtained for MHI and THI, respectively, from ROC curve analysis. Postoperative BCVAs in the MHI ≥ 0.475 group and in the THI ≥ 0.973 group was better than that in the MHI < 0.475 and in the THI < 0.973 group, respectively (Mann-Whitney U test:P MHI = 0.013, P THI = 0.008) .

Conclusion: An MHI ≥ 0.475 or a THI ≥ 0.973 may be predictive factors for a good visual prognosis after IMH surgery.