Ultrasound Biomicroscopy-Guided Assessment of Acute Corneal Hydrops

Abstract

To analyze the morphologic features of acute hydrops and treatment success using ultrasound biomicroscopy (UBM). Prospective interventional case series. Fourteen patients (14 eyes) affected by keratoconus with acute corneal hydrops. Patients with acute hydrops were treated with intracameral injection of 0.15 ml of 14% perfluoropropane (C₃F₈) gas. The parameters evaluated on UBM included the location and length of the Descemet's membrane (DM) tear and corneal thickness at the central corneal thickness at the area overlying the DM tear (CT₀), corneal thickness 2.5 mm from the central point (CT₂.₅), and peripheral corneal thickness 2.0 mm from the scleral spur toward the corneal side (CT(P)). The ratio of CT₂.₅ to CT₀ was calculated to obtain the hydrops resolving index (HyRI). The DM tear was visualized with UBM in all cases and slit-lamp microscopy in 9 of 14 eyes. The mean length of DM tears at presentation was 1.74 ± 0.77 μm. Patients with zone 3 corneal edema had a longer DM tear compared with patients with zone 2 corneal edema (1.27 ± 0.55 vs 2.02 ± 0.79 μm, respectively, P = 0.09). Significant positive correlations were seen between DM tear length and CT₂.₅ and CT(p) (r = 0.790, P = 0.020 and r = 0.766, P = 0.027, respectively). An intracameral gas bubble was seen abutting the edges of the tear in all cases. At the 6-week follow-up, the apposition of the DM and the overlying stroma occurred in all eyes, and resolution of epithelial edema and intrastromal cysts were seen in 11 of 13 cases (84.6%) and 12 of 13 cases (92.3%). The mean values of CT₀, CT₂.₅, and CT(p) at presentation were 2359.69 ± 582.26 μm, 1911.15 ± 502.60 μm, and 1156.46 ± 275.77 μm, respectively, which decreased to 398.15 ± 31.65 μm (P = 0.0), 453.46 ± 68.45 μm (P = 0.0), and 638.00 ± 62.17 μm (P = 0.0), respectively. The mean HyRI showed a significant increase from 0.80 ± 0.05 at the time of presentation to 1.13 ± 0.12 (P = 0.03) at 3 months follow-up. Ultrasound biomicroscopy is a useful tool for quantitative and qualitative study of the morphologic features of acute hydrops. The author(s) have no proprietary or commercial interest in any materials discussed in this article.