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

Area of Science:

• Ophthalmology
• Optometry
• Retinal Imaging

Background:

• Optic nerve head (ONH) and retinal layer thickness are crucial for diagnosing glaucoma.
• Microdisks (MDs) present unique challenges in ONH assessment due to their small size.
• Understanding age-related changes in ONH parameters is vital for accurate glaucoma detection.

Purpose of the Study:

• To compare ONH and inner retinal layer thickness between children and adults with microdisks (MDs) and normal-sized disks (NSDs).
• To investigate age-related differences in ocular parameters within MD and NSD groups.
• To establish baseline ONH and retinal measurements for improved glaucoma diagnosis in MD patients.

Main Methods:

• A case-control study involving 172 eyes, divided into four groups: children with MD, adults with MD, children with NSD, and adults with NSD.
• Spectral domain optical coherence tomography (OCT) was used for high-resolution imaging.
• Key parameters measured included neuroretinal rim area, cup-to-disk ratio (CDR), cup volume, peripapillary retinal nerve fiber layer (pRNFL) thickness, and macular ganglion cell-inner plexiform layer (mGCIPL) thickness.

Main Results:

• Significant age-related differences were observed in ONH parameters (NRR area, CDR, cup volume) and pRNFL thickness in the normal-sized disk (NSD) group.
• In contrast, only NRR area and nasal pRNFL thickness showed statistically significant differences between children and adults with microdisks (MDs).
• Macular ganglion cell-inner plexiform layer (mGCIPL) thickness did not show significant age-related differences in either group.

Conclusions:

• ONH parameters and pRNFL thickness exhibit distinct age-related variations in individuals with normal-sized optic disks.
• Microdisks in children and adults do not display significant age-related differences in ONH parameters or inner retinal layer thickness.
• Glaucoma evaluation in microdisks should prioritize ONH parameters, as physiological age-related cup enlargement is not expected, making increased cup volume a key indicator of glaucomatous damage.