Foveal actual defect (FAD): A novel OCT biomarker for prognosis and surgical decision support in idiopathic full-thickness macular hole.

Abstract

Background: The current classification of idiopathic full thickness macular holes (IFTMH) based on the minimum linear diameter (MLD) parameter does not provide the surgeon with accurate prognostic information regarding the surgical outcome.

Purpose: To investigate whether the preoperative Foveal Actual Defect (FAD) can predict postoperative macular hole outcomes and could be a key point in new Decision Support System for IFTMHs surgery.

Patients and methods: Fifty-seven eyes of fifty-three patients with iFTMH, who underwent 25-gauge PPV, ILM peeling and gas tamponade (GT) were recruited for this retrospective, consecutive case, interventional study. The choice of additional surgical techniques was determined individually depending on the size of the FAD. Surgery outcome-related factors were also assessed.

Results: The primary closure rate was 94.7 % (54/57). Three eyes (5.3 %) with persistent MHs required an additional surgery. In all of these eyes, the MH closed after the second surgery. Mean BCVA (logMAR) significantly improved after surgery from 0.8 ± 0.3 (ME = 0.7; IQR: 0.5-1.0) to 0.1 ± 0.2; (ME = 0.1; IQR: 0.1-0.2) (P = 0.0001). There is a statistically significant difference (U = 78.0; Р = 0.05) in the preoperative FAD indicators between groups with a primary closed holes at the first day (ME = 217; IQR: 140-391) and unclosed holes (ME = 370; IQR: 222-697). The probability of MH closing by 14 days after surgery with FAD < 400 µm increases 1.3 times (RR = 1.3, 95 %CI: 1.0-1.6; φ = 0.4; P = 0.02). The MLD indicator in the primary hole closing group at first postop day did not statistically significantly different from those who did not close, but in the group with a primary closed holes at 14-th postop day the MLD indicator statistically significantly (U = 10.0; P = 0.005) was less (ME = 390; IQR: 277 - 492) compared to the unclosed holes (ME = 642; IQR: 558 - 866). There is a statistically significant correlation between postoperative BCVA at 6 month and preoperative OCT parameters: BD - ρ = 0.23 (P = 0.02), MLD - ρ = 0.34 (P = 0.005), FAD - ρ = 0.37 (P = 0.002). The regression model showed that PreopBCVA, FAD, and BD were statistically significant: PostBCVA = 0.22 × PreBCVA + 0.00001 × BD + 0.00001 × FAD (σPreBCVA = 0.05, σBD = 0.000006, σFAD = 0.000005, R² = 0.75, P < 0.01).

Conclusion: The proposed Decision Support System based on a new preoperative OCT-parameter Foveal Actual Defect (FAD) allows a personalized assessment of macular hole surgery.