Defining objective criteria for glaucomatous optic neuropathy, rather than relying on clinical assessments alone, is needed for comparing outcomes across clinical research studies, according to a speaker at the virtual Association for Research in Vision and Ophthalmology meeting.
“The need for a definition of glaucomatous optic neuropathy so that we can compare across clinical research studies was indicated by the fact that most studies these days still use the definition ‘characteristic glaucoma disc and field as defined by experts’ ... to identify glaucoma. This might be pejoratively described as the ‘three guys in a smoke-filled room method’ and certainly does not inspire confidence that three people in one institution would have the same definition as another institution,” Harry A. Quigley, MD, said.
Quigley and colleagues examined clinical data and evaluations, OCT results and visual field tests for 2,850 eyes of 1,531 patients entered into a secure online database by 13 international centers. Glaucoma specialists from each clinic graded each patient’s eye as definite, probable or not glaucomatous optic neuropathy (GON), he said.
The study only included patients with open-angle glaucoma. Clinicians submitted a diagnosis for each patient and two reliable OCT retinal nerve fiber layer and two reliable Humphrey visual field analyzer (HFA) scans for each eye.
According to the study, approximately 59% of eyes had definite GON, 20% had probable GON and 22% did not have GON.
In order to have a criterion that best matched definite GON as judged by clinicians, the researchers evaluated OCT and HFA data from either the most recent pair of tests or prior pair of tests. If researchers found a patient’s OCT was abnormal in a quadrant and also had an HFA with a glaucoma hemifield test (GHT) abnormality in the same position, the sensitivity for definite GON was 77% and the specificity was 98%, Quigley said.
Researchers also found by using only the most recent single test pairs of OCT with a quadrant defect and HFA with a matching GHT abnormality, the sensitivity for definite GON was 73% and the specificity was 98%, Quigley said.
Quigley noted further testing of the objective criteria is in progress. – by Robert Linnehan
Quigley HA. Evaluating an objective definition of glaucomatous optic neuropathy: An international collaborative effort. Presented at: Association for Research in Vision and Ophthalmology annual meeting; May 6, 2020 (virtual meeting).
Disclosure: Quigley reports no relevant financial disclosures.