Measurment of Optic Disc Parameters, RNFL Thickness and Ganglion Cell Complex in Myopic, Hypermetropic and Emmetropic Patients Using OCT and Axial Length Measurments

Correlation Between Axial Length and Degree of Refractive Error With Optic Disc Parameters , Ganglion Cell Complex and Peripapillary RNFL Thickness

To evaluate the optic disc parameters, thickness of ganglion cell complex (GCC), and thickness of peripapillary retinal nerve fiber layer (RNFL) in myopic and hyperopic and emmetrop patients using optical coherence tomography (OCT), and to correlate these changes with axial length and degree of refractive error.

Refractive errors, particularly myopia and hyperopia, are among the most common ocular conditions globally, affecting both children and adults .

Myopia is frequently associated with axial elongation, which may induce structural changes in the posterior segment of the eye such as thinning of the peripapillary retinal nerve fiber layer (RNFL) and alteration of optic disc parameters . Hyperopia, conversely, is linked to shorter axial lengths and has been shown to affect retinal and optic nerve anatomy in distinct ways .

Optical coherence tomography (OCT), particularly spectral-domain OCT (SD-OCT), allows for high-resolution imaging of the RNFL and ganglion cell complex (GCC), which are crucial for visual processing. These layers are known to undergo subtle changes not only due to disease processes like glaucoma or optic neuropathies but also as a result of anatomical differences induced by refractive status .

While many studies have independently evaluated RNFL or GCC in myopic and hyperopic patients, few have directly compared these two refractive states while correlating structural findings with axial length and refractive error magnitude . Including an emmetropic control group provides a normative benchmark, enhancing the clinical relevance of the findings .

This study seeks to fill this gap by offering a comparative structural analysis using OCT, aiming to enhance diagnostic sensitivity and understanding of optic nerve and macular changes in various refractive profiles.

Inclusion Criteria:

• Adults age starting from 18 years old Diagnosed with myopia (≤ -0.50 D) or hyperopia (≥ +0.50 D) Clear ocular media for high-quality OCT imaging No prior ocular surgeries Willing to provide informed consent IOP below 21

Exclusion Criteria:

• Presence of glaucoma or optic nerve pathologies Retinal diseases or degenerative changes Systemic diseases affecting the eye (e.g., diabetes, hypertension) History of trauma or intraocular surgery High astigmatism (> ±2.00 D) Poor OCT image quality