Use of Ocular Response Analyzer Output Data in the Management of Low Intraocular Pressure after Glaucoma Filtration Surgery

AIM: To highlight potential benefits of using Reichert's ocular response analyzer (ORA) for intraocular pressure (IOP) measurement following glaucoma filtering surgery (GFS), especially in cases of low IOP. BACKGROUND: Goldmann applanation tonometry (GAT) is widely regarded as the gold standard of IOP measurement in clinical practice. The ORA also calculates corneal biomechanics, which is used in the calculation of the cornea-compensated IOP (IOPcc).(1) This useful, previously unknown information can be used to guide management in challenging clinical cases. CASE DESCRIPTION: A 78-year-old lady underwent right trabeculectomy with mitomycin C. During the first 9 months postoperatively, IOP's when measured with GAT, were found to be low (ranging between 2 mm Hg and 5 mm Hg). The patient displayed no clinical features of hypotony and visual acuity remained stable throughout. IOP was also measured with Reichert's ORA, which gives readings for corneal hysteresis (CH), corneal resistance factor and corneal corrected IOP. IOPcc measurements obtained with ORA were consistently higher, ranging from 6.7 mm Hg to 9.3 mm Hg and were more in keeping with the clinical features of the case. CONCLUSION: This case highlights the possibility that GAT can underestimate the true IOP in eyes with low IOP following GFS, as it does not account for corneal biomechanical properties. CLINICAL SIGNIFICANCE: Ocular response analyzer (ORA)—measured IOPcc may be a useful adjunct in reassuring surgeons to manage postoperative numerical hypotony conservatively in the absence of any clinical signs of hypotony. HOW TO CITE THIS ARTICLE: Dawson S, Mohite A. Use of Ocular Response Analyzer Output Data in the Management of Low Intraocular Pressure after Glaucoma Filtration Surgery. J Curr Glaucoma Pract 2023;17(2):104-105.