Abstract
Purpose :
The OHTS risk calculator was developed and validated (Ophthalmology 2007; 114(1):10-19) to estimate the risk of developing primary open angle glaucoma for ocular hypertensives (OHT). The OHTS calculator was developed before the regular clinical use of spectral domain optical coherence tomography (OCT). The purpose of this study was to evaluate a glauoma risk calculator modified to include OCT data.
Methods :
The OHTS calculator Point System method was modified to assign points for circumpapillary retinal nerve fiber layer (cpRNFL) thickness based on Maestro2 (Topcon, Inc.,Tokyo, Japan) OCT measurements (average of both eyes) rather than subjective evaluation of the vertical cup-to-disc ratio. Points were assigned as follows: 0 points if cpRNFL > 90 µm, 1 point if 85 µm < cpRNFL <= 90 µm, 2 points if 83 µm < cpRNFL <= 85 µm , 3 points for 83 µm <= cpRNFL > 80 µm, or 4 points if cpRNFL <= 80 µm. The remaining elements of the points system were used as is: Central corneal thickness (CCT), Age, intraocular pressure (IOP) and pattern standard deviation (PSD) from visual field measurements.
Although the OHTS calculator was developed to predict the 5-year conversion from OHT to POAG, we tested the ability to distinguish suspected glaucoma from diagnosed glaucoma in a convenience sample of patients seen at the Illinois College of Optometry (ICO).
Results :
A total of 236 (108 glaucoma, 128 suspect or normal) patients were included in the ICO dataset, majority African-American. The area under the curve (AUC) for the modified OHTS calculator was 0.85. For comparison, the AUC for cpRNFL alone was 0.81.
Figure 1 shows the receiver operating curves for the modified OHTS model (AUC = 0.85) as well as a generalized linear model based on the cpRNFL from both eyes and the age of the patient (AUC = 0.84).
Conclusions :
An OHTS risk calculator, modified to replace subjective vertical cup-to-disc ratio from a fundus image assessment with an objective measurement of cpRNFL from Maestro2 OCT improves performance over simple summary parameters from OCT alone.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.