Effect of intravitreal dexamethasone implant (Ozurdex®) injections on corneal biomechanical properties measured using ocular response analyzer

PURPOSE: The purpose of the study was to evaluate Ocular Response Analyzer (ORA) measurements and endothelial cell density (ECD) in patients who received intravitreal dexamethasone implant (Ozurdex®) injection for diabetic macular edema.
METHODS: Twenty-three eyes of 13 patients who receive intravitreal dexamethasone implant injection (Group 1) for diabetic macular edema and 33 eyes of 33 healthy individuals (Group 2) were included in the study. All participants underwent a complete ophthalmologic examination including intraocular pressure measurement with Goldmann applanation tonome-ter (IOP-GAT), ORA measurements, and specular microscopy.
RESULTS: The mean age of the patients was 65.43±8.20 (49–75) in Group 1 and 61.94±4.52 (56–71) in Group 2 (p=0.114). The mean IOP-GAT was significantly higher in Group 1 (18.22±3.41; range 12–28 mmHg) than in Group 2 (15.41±3.07; range 8–21 mmHg) (p=0.02). The mean ECD was 2632.4±209.6 (2232–3067) cell/mm2 in Group 1 and 2567±206.37 (2140–2854) cell/mm2 in Group 2 (p=0.60). The mean corneal resistance factor (CRF) was 12.16±2.35 (7.4–15.3) mmHg in Group 1 and 10.18±1.83 (6.7–14.2) mmHg in Group 2 (p=0.02). Mean corneal hysteresis (CH) in Groups 1 and 2 was 8.87±2.45 (4.1–13.4) mmHg and 10.47±1.43 (6.9–13.2) mmHg, respectively (p=0.001). Mean corneal compensated IOP and Goldman correlated IOP (IOPg) were higher in Group 1 (24.72±7.12; range 12.1–36.4 mmHg and 23.21±7.01; range 14.2–36.2 mmHg) than in Group 2 (14.95±3.6; range 8.3–22.9 mmHg and 14.33±3.84; range 6.3–21.7 mmHg) (p<0.001). IOP-GAT was correlated with IOPg (p=0.01).
CONCLUSION: Intravitreal Ozurdex® injection effects IOP, while it has no significant effect on ECD. Ozurdex® injections changed corneal biomechanical properties such as CH and CRF. Thus, ORA may be a useful to avoid underestimating the IOP and missing the alteration of elastic properties of the cornea.