Studying the Correlation between Axial Length and Retinal Nerve Fiber Layer and Macular Thickness by Spectral-Domain Optical Coherence Tomography

R.H.Abd AL-Fatah, A.H. El Habbak, O.M. Kamal, A.A. Shebl
2021 Benha Journal of Applied Sciences  
The ability to see well is critical in one's life. Our retina is similar to a film in a camera, generating electrical impulses that are then sent to the brain, where they are interpreted as visual pictures by retinal nerve fibres in the brain. A healthy macula provides the sharpest vision, which is essential for jobs that need a lot of visual processing power. To ensure the efficacy of treating macular injuries, it is essential to measure the thickness of the macula before and after therapy.
more » ... gnostic imaging using OCT offers in vivo study of various retinal layers and anterior segment with 1-15 m resolution without contacting or invasively implanting any equipment into the patient's body Because it accurately measures RNFL and macular thickness and identifies early structural changes, it becomes an essential diagnostic tool for glaucoma, macular edoema, and other retinal and optic nerve disorders. It may also be used to follow up on patients with macular degeneration. It is now possible to create 3D pictures with unprecedented speed and quality thanks to the advent of the new SD-OCT technology. RNFL and macular thickness may be evaluated in a safe, consistent, rapid, and objective manner using this approach. Studying pRNFL and macular thickness in hyperopia, myopia, and emmetropia using spectral domain optical coherence tomography has the goal of learning how they relate to acuity levels (AL). Methods: The 45 eyes of 23 healthy volunteers were sorted into three categories based on their axial length: Group I (myopic) consists of 15 people (axial length: 24.6-27 mm). Eyes in the second group (Emmetropic) have (axial length: 22.6-24.5 mm). There are 15 eyes in this group that are hypermetropic (axial length: 20-22.5 mm). Spectral-domain Optical Coherence Tomography was utilised to quantify macular thickness and peripapillary RNFL thickness in all quadrates after a complete clinical examination of the participants. Results: To minimise the impact of age-related retinal changes, we structured the present research to include participants ranging in age from 14 to 40. Age had no effect on macular or pRNFL thickness, which were found to be identical. Our research identified no significant differences in macular thickness and RNFL thickness across other demographic characteristics including gender and eye preference. Because of this, these aspects aren't relevant when trying to determine what RNFL readings are typical. The research groups did not vary in central macular thickness (CMT). In all quadrants (temporal, inferior, and nasal), except in the superior quadrant, parafoveal thickness does not vary significantly. However, there was a strong negative association between it and other variables across research groups. There was a strong negative connection in the superior, temporal, and nasal quadrants for perifoveal thickness, but there was no difference in the inferior quadrant. This suggests that All quadrants had a thicker parafoveal zone than the perifoveal region. The "double hump pattern" and the "ISNT rule" were evident in our analysis of pRNFL thickness. The AL demonstrated a negative relationship with the thickness of the RNFL. In both the superior and inferior quadrants, this was statistically significant. In terms of the temporal and nasal quadrants, there was no significant difference between the research groups. It can be concluded that the lengthening of AL has a significant negative correlation with the macula retinal thickness in the superior, nasal and temporal quadrants as well as the inner parafovea in the superior quadrant. However, there was no correlation between AL lengthening and the macula's central thickness. In all three groups, pRNFL exhibited the distinctive "double hump pattern" and adhered to the "ISNT rule." When it came to the temporal and nasal quadrants, there was no statistically significant difference between the research groups in terms of RNFL thickness and axial length. To accurately assess the thickness of various retinal tissues, such as RNFL, OCT is a helpful tool. This helps in early glaucoma diagnosis, follow-up, and treatment of patients to prevent them from irreversible vision loss.
doi:10.21608/bjas.2021.214377 fatcat:pn7lb3p7cncptcvr54qtzkxshe