Baseline glaucoma severity is not significantly associated with longitudinal rates of minimum rim width (MRW), peripapillary retinal nerve fiber layer (RNFL), or macular ganglion cell layer (GCL) thickness changes according to a prospective cohort study, published in the American Journal of Ophthalmology. However, the report shows that GCL thickness was “able to statistically contrast the rate of change between healthy [patients] and glaucoma patients throughout the disease spectrum.”
This study was carried out at 2 centers in Nova Scotia, Canada. Patients (n = 132) with glaucoma and healthy controls (n = 57) were assessed by optical coherence tomography (OCT) at least 5 times at 6-month intervals. The rate of change in MRW, RNFL, and GCL thickness were estimated and the change in these parameters was used to predict glaucoma severity.
Patients and controls were aged median 74.3 (IQR, 67.7-80.2) and 67.2 (IQR, 63.4-74.8) years, they had been evaluated by OCT 9 (IQR, 8-10) and 8 (IQR, 7-9) times, baseline MRW was 173 (IQR, 146-204) and 290 (IQR, 259-319) μm, RNFL thickness was 66 (IQR, 57-74) and 93 (IQR, 88-99) μm, and GCL was 37 (IQR, 32-41) and 49 (IQR, 46-51) μm, respectively.
During follow-up, the glaucoma and control cohorts had a similar proportion of individuals with significant reduction to MRW (52.3% vs 42.1%; P =.26), RNFL (46.2% vs 35.1%; P =.21), and GCL (51.5% vs 43.9%; P =.42) thickness.
After adjusting for covariates, the glaucoma cohort had a significantly faster rate of GCL thickness change compared with controls (mean group difference, -0.17 μm/year; P =.03) but not RNFL thickness (mean group difference, -0.09 μm/year; P =.54) or MRW change (mean group difference, -0.16 μm/year; P =.74).
Age was a significant covariate for GCL thickness change (-0.07 μm/year/year of age; P =.03).
This study may have been limited due to underrepresentation of patients with severe disease at baseline (9.8% had baseline visual field of -12 dB or worse).
In this longitudinal study, the investigators found that OCT monitoring of GCL thickness change over time may be a useful parameter for monitoring structural glaucoma progression but that longitudinal MRW, RNFL, or GCL thickness changes were not indicative of baseline disease severity.
Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.
Kim YW, Sharpe GP, Hutchison DM, et al. Impact of glaucoma severity on rates of neuroretinal rim, retinal nerve fiber layer, and macular ganglion cell layer thickness change. Am J Ophthalmol. 2022;S0002-9394(22)00039-3. doi:10.1016/j.ajo.2022.01.019