Considering the effect of age and glaucoma progression on the thickness of the circumpapillary retinal nerve fiber layer (cpRNFL) over a 10-year period, a team of researchers from Sweden found no significant differences in the change of cpRNFL thickness in glaucoma patients compared to healthy subjects between visits.
The investigation, published online in Acta Ophthalmologica, used OCT to re-examine a group of healthy individuals and a group of glaucoma patients 10 years after they were first evaluated in 2008, to analyze the effect of aging on cpRNFL thickness with a long-time follow-up interval and to compare the results with the changes observed in glaucoma patients. The study also evaluated the performance of a set of OCT progression analyses in the same subjects.
The results showed a small effect of age on the cpRNFL and a higher rate of thinning in glaucoma patients with mild to moderate disease defined by their visual fields, but it was still limited and statistically non-significant. The findings also suggested a thickening of the cpRNFL in eyes with severe glaucoma.
The researchers found OCT progression analyses generated a substantial number of false positives and, considering the current literature, the investigators said using OCT for glaucoma follow-up “may not be straightforward.”
The study included 69 healthy individuals and 49 glaucoma patients. The researchers measured the cpRNFL in both groups twice with OCT at each of the two visits made 10 years apart. Both visits also included 24-2visual field testing.
The study reported an average cpRNFL thickness deterioration of approximately -0.16μm/year in the healthy cohort, an increase of 0.03μm/year in the glaucoma cohort and a deterioration of -0.24μm/year in eyes with less severe glaucoma.
The researchers found no statistically significant differences between the groups. For 17 (30%) of 56 healthy individuals, at least one of the three different OCT progression analyses incorrectly indicated progression.
Öhnell HM, Heijl A, Bengtsson B. Ageing and glaucoma progression of the retinal nerve fibre layer using spectral-domain optical coherence tomography analysis. Acta Ophthalmologica. August 9, 2020. [Epub ahead of print].