Long-term changes in ocular rigidity following scleral buckling for rhegmatogenous retinal detachment

Purpose To investigate the long-term effect of scleral buckling on corneal biomechanics and the effect of change of scleral properties on intraocular pressure (IOP) measurements. Methods This is a prospective case series, patients with rhegmatogenous retinal detachment prepared for scleral buckling were included. Goldmann applanation tonometry was used to measure IOP (GAT IOP). Ocular Response Analyzer (ORA) was used to measure corneal hysteresis (CH), corneal resistance factor (CRF), goldmann-corrected IOP (IOPg), and corneal-compensated IOP (IOPcc) preoperatively, and 1, 3, and 6 months postoperatively. Results Thirty-three eyes included in the final analysis, with an average age 38.4 +/- 16.2 years. CH and CRF decreased significantly at first, third, sixth months post-scleral buckling; however, this effect decreased with time as follows; preoperative: 8.9 +/- 1.5 and 8.5 +/- 2.1, first month: 6.8 +/- 1.6 and 7.1 +/- 1.8 (P value = 0.00, 0.002), third month: 7.8 +/- 1.5 and 7.6 +/- 1.6 (P value = 0.001, 0.008), and sixth month: 7.7 +/- 1.3 and 7.6 +/- 1.7 (P value = 0.002, 0.055). IOP cc was 19.3 +/- 3.6, 17.1 +/- 4, and 17.6 +/- 2.9 at 1, 3, and 6 months, and these readings were significantly higher than GAT (13.6 +/- 7.6, 12.4 +/- 5.1, and 12.1 +/- 2.9, P values = 0.00) and IOPg (14.9 +/- 3.6, 13.5 +/- 4.1, and 13.9 +/- 3.5, P values = 0.00). The change in CH at each visit is correlated with the difference between the IOPcc and GAT measurements. Conclusion The conventional Goldmann applanation tonometry underestimates post buckle IOP measurements due corneal biomechanics changes. ORA might be an alternative and accurate method of measurement; however, further investigation is warranted.