# A Comparative Study of Growth Patterns in Microdisks and Normal-Sized Optic Disks Using OCT

## TL;DR

This study compares optic nerve head and retinal layer thickness in children and adults with microdisks and normal-sized disks using OCT, finding significant differences in normal-sized disks but not in microdisks.

## Contribution

The study provides new insights into age-related differences in optic nerve head parameters in microdisk and normal-sized disk populations.

## Key findings

- Children and adults with normal-sized disks showed significant differences in NRR area, CDR, cup volume, and pRNFL thickness.
- Children and adults with microdisks only differed in NRR area and nasal pRNFL thickness.
- Cup volume increase in microdisks should raise suspicion of glaucomatous damage due to lack of physiological enlargement with age.

## Abstract

Purpose: To compare the parameters of the optic nerve head (ONH) and inner retinal layer thickness between children and adults with microdisks (MDs) and normal-sized disks (NSDs) using optical coherence tomography (OCT).

Methods: A case-control study that included 172 eyes. Four groups of patients were created and matched according to gender and disk size: 41 children with MD (disk size between 1.42 and 1.60 mm2), 41 adults with MD, 45 children with NSD (disk size between 1.80 and 2.30 mm2), and 45 adults with NSD.

All subjects were imaged with spectral domain OCT. Neuroretinal rim (NRR) area, cup–disk ratio (CDR), cup volume, peripapillary retinal nerve fiber layer (pRNFL) thickness, and macular ganglion cell–inner plexiform layer (mGCIPL) thickness were obtained.

Results: There was a statistical difference in the NRR area (p < 0.001), average CDR (p < 0.001), cup volume (p < 0.001), and average pRNFL thickness (p < 0.001) between children and adults with NSD. However, comparing children and adults with MD, the only differences found were the NRR area and nasal pRNFL thickness (p = 0.009 and 0.010, respectively).

Conclusions: In conclusion, the ONH parameters and pRNFL thickness are different in children and adults with NSD. On the contrary, MD belonging to children and adults did not have significant differences in ONH parameters and inner retinal layer thickness.

According to these findings, the evaluation of a glaucomatous lesion in MD should rely on the ONH parameters and an increase in the cup volume must raise the suspicion of glaucomatous damage, because the physiological enlargement of the cup with age in a MD with age is not to be expected.