Abstract
Purpose :
Wide variations in surgical technique exist in glaucoma filtration surgery with varying degrees of reported success. This study aims to identify modifiable surgical parameters associated with greatest success.
Methods :
Cross-sectional study of 121 blebs of 77 patients who had undergone prior Trabeculectomy (Trab, n=58) or Deep Sclerectomy (DS, n=63) with/without Mitomycin C surgery at least one year prior for glaucoma. Swept source anterior segment-optical coherence tomography (AS-OCT, Anterion®, Heidelberg Engineering) was used to capture scleral flap dimensions, sclerostomy and Trabeculo-descemet’s window (TDW) dimensions and distance from iridocorneal angle (Figure 1). Image segmentation and analysis was performed using Matlab (Mathworks).
Results :
The proportion of complete success (CS; IOP ≤18mmHg with no medications), qualified success (QS; IOP ≤18 with medications) and failure (F; IOP>18mmHg) in the Trab and DS cohorts were 44.8% vs 44.4%, 36.2% vs 28.6%, and 19.0% vs 27.0% respectively, with a mean post-operative follow up of 7.6 years (IQR 2.6-9 years). In the Trab cohort, subjects with CS had longer scleral flap length from angle (2.9 vs 2.0mm, p<0.001), greater flap width (3.9 vs 3.3 mm, p<0.003), greater sclerostomy height (660 vs 504µm, p=0.008) and shorter distance of sclerostomy base from angle (159 vs 433µm, p<0.001) compared to the QS/F group (Figure 2), with a corresponding increase in bleb height (UQ: 1.9; Q: 1.4; F: 1.3mm) and lower IOP (8.1 vs 16.0 mmHg, 0 vs 1.8 medications). In the DS cohort, scleral flap length, width and thickness was similar between CS and QS/F groups. TDW length was greater in the CS group but this did not reach significance (541 vs 483µm, p=0.15). Mean IOP in the DS cohort was 11.1 vs 14.6mmHg and 0 vs 1.7 medications in the CS vs QS/F groups.
Conclusions :
A longer and wider scleral flap, greater sclerostomy length and a sclerostomy location closer to the iridocorneal angle may be associated with greater complete surgical success in Trabeculectomy patients.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.