In the early stages of glaucoma, individuals who have senile sclerotic optic disc characteristics may exhibit faster circumpapillary RNFL thinning, a new study published in the American Journal of Ophthalmology suggests.
The investigation considered four optic disc phenotypes in early glaucoma—senile sclerotic, cup enlargement, focal ischemic and myopic glaucomatous—and found different RNFL thinning patterns in each.
In addition to senile sclerotic optic disc types, the researchers noted that focal ischemic
phenotypes also showed faster rates of global circumpapillary RNFL thinning compared with the other two classifications.
The study enrolled 218 early glaucoma eyes that were followed-up for at least three years and underwent a minimum of four SD-OCT scans. The eyes were then grouped as follows: 76 generalized cup enlargement, 53 focal ischemic, 22 myopic glaucomatous and 67 senile sclerotic.
Specifically, the senile sclerotic group had the fastest mean rate of global circumpapillary RNFL thinning (-1.30µm/year, -0.73µm/year), followed by focal ischemic (-0.97µm/year, -0.57µm/year), myopic glaucomatous (-0.81µm/year, -0.36µm/year) and generalized cup enlargement (-0.75µm/year, -0.40µm/year).
The different phenotypes differed not only in terms of thinning, but also in patterns of deterioration.
The inferior temporal sector had the fastest rate of circumpapillary RNFL thinning among the regional measurements except for in the myopic glaucomatous group, which showed a slower rate of deterioration. In comparison, a more localized inferior circumpapillary RNFL thinning was observed in the generalized cup enlargement and focal ischemic groups, while the senile sclerotic group showed a distinct rapid rate of circumpapillary RNFL thinning both in the superior and inferior quadrants.
“Therefore, in early stages of glaucoma, these patterns of circumpapillary RNFL thinning among phenotypes should be analyzed with caution, as some may have rapid localized forms of progression masked by a slow rate of global progression,” the researchers wrote in their paper.
In a multivariable analysis, generalized cup enlargement and myopic glaucomatous phenotypes were linked to markedly slower global rates of circumpapillary RNFL thinning when compared with the senile sclerotic phenotype.
Considering these findings, individuals with early glaucoma who have senile sclerotic optic disc characteristics may benefit from more frequent monitoring and advanced therapy if circumpapillary RNFL thinning is detected.
David RCC, Moghimi S, Ecici E, et al. Rates of RNFL thinning in distinct glaucomatous optic disc phenotypes in early glaucoma. Am J Ophthalmol. April 25, 2021. [Epub ahead of print].