The Influence of Optical Coherence Tomography Measurements of Retinal Nerve Fiber Layer on Decision-Making in Glaucoma Diagnosis

Purpose: To quantify the influence of spectral domain optical coherence tomography (SDOCT) on decision-making in patients with suspected glaucoma. Methods: A prospective cross-sectional study involving 40 eyes of 20 patients referred by community optometrists due to suspected glaucoma. All patients had disc photographs and standard automated perimetry (SAP), and results were presented to 13 ophthalmologists who estimated pre-test probability of glaucoma (0–100%) for a total of 520 observations. Ophthalmologists were then permitted to modify probabilities of disease based on SDOCT retinal nerve fiber layer (RNFL) measurements (post-test probability). The effect of information from SDOCT on decision to treat, monitor, or discharge was assessed. Agreement among graders was assessed using intraclass correlation coefficients (ICC) and correlated component regression (CCR) was used to identify variables influencing management decisions. Results: Patients had an average age of 69.0 ± 10.1 years, SAP mean deviation of 2.71 ± 3.13 dB, and RNFL thickness of 86.2 ± 16.7 μm. Average pre-test probability of glaucoma was 37.0 ± 33.6% with SDOCT resulting in a 13.3 ± 18.1% change in estimated probability. Incorporating information from SDOCT improved agreement regarding probability of glaucoma (ICC = 0.50 (95% CI 0.38 to 0.64) without SDOCT versus 0.64 (95% CI 0.52 to 0.76) with SDOCT). SDOCT led to a change from decision to “treat or monitor” to “discharge” in 22 of 520 cases and a change from “discharge” to “treat or monitor” in 11 of 520 cases. Pre-test probability and RNFL thickness were predictors of post-test probability of glaucoma, contributing 69 and 31% of the variance in post-test probability, respectively. Conclusions: Information from SDOCT altered estimated probability of glaucoma and improved agreement among clinicians in those suspected of having the disease.