Despite advances in ocular imaging and perimetry, it’s still difficult to distinguish between healthy, suspect and manifest glaucoma patients due to a lack of consistent clinical criteria, which leaves the definitive diagnosis to the individual eye care practitioner’s expertise and assessment, a study in Ophthalmology Glaucoma suggests.

Researchers from the University of New South Wales reviewed the medical records of healthy, glaucoma suspect and glaucoma patients (the latter were diagnosed by an expert clinician) seen at the Centre for Eye Health in 2015 (148, 664 and 129, respectively) and in 2018 (242, 464 and 126, respectively). One eye of each patient was selected for the study.

The investigation looked for trends in intraocular pressure (IOP), central corneal thickness (CCT), visual fields (VF) and optical coherence tomography (OCT) results to identify factors that would help separate the three diagnoses.

The study found only a small number of clinical parameters that were significant across all diagnostic pairings. In 2015, the researched identified only three out of 23 testing parameters: IOP, pattern standard deviation and seven o’clock retinal nerve fiber layer thickness. In the 2018 group, the researchers noted only one commonality: vertical cup-to-disc ratio.

Additionally, few parameters overlapped when comparing 2015 and 2018 results, which highlighted inconsistencies in the models between years, in part because the parameters used for diagnostic separation changed between the groups and years, the researchers noted.

 Still, further analysis showed good separation between healthy and glaucoma patients.

The researchers also found glaucoma suspects had substantial overlap with healthy and glaucoma cohorts.

“These results highlight the nebulousness and heterogeneity (at patient-, instrument- and clinician-related levels) of glaucoma diagnosis that remains contingent upon individual clinical expertise and assessment, the researchers concluded in their paper.