Abstract :
Introduction: The retinal nerve fibre layer is a most crucial indicator of optic nerve damage in glaucoma as it advances visual field loss. Thickness of the RNFL can be measured using high resolution OCT. We conducted this study to evaluate the alterations in retinal nerve fibre layer thickness measured by SD- OCT in ametropes and to find various factors affecting RNFL thickness.
Aim: Study of retinal nerve fibre layer thickness (RNFL) by Optical Coherence Tomography (OCT) in ametropes in tertiary care hospital of central India.
Setting and Design: Hospital based prospective observational study included 300 eyes of 150 participants. Visiting ophthalmology outpatient department Gandhi medical college and fulfilling the inclusion and exclusion criteria.
Materials and Methods: Patients were divided into five groups of 60 eyes each on the basis of refractive status of eyes into emetropia, low hypermetropia, moderate hypermetropia, low mypopia and moderate mypopia. Subjects were subjected to OCT scan and RNFL thickness was measured. All groups were evaluated and observations were noted and results were analysed.
Statistical Analysis used: To find the association between degree of ametropia and RNFL thickness one way ANOVA test was used. Correlation between axial length and RNFL was assesed by pearson correlation coefficient. p value
Result: RNFL thickness in different groups followed ISNT rule with inferior quadrant showing the greatest thickness followed by the superior, nasal and temporal quadrants. The average RNFL thickness in emmetropics, Low hyperopic, Moderate hyperopic, Low myopic, Moderate myopic was 111.90?m, 110.58 ?m, 114.59 ?m, 103.33 ?m, 93.33 ?m respectively, wheras average axial length was 23.85mm, 22.36mm, 21.33mm, 24.72mm, 25.63mm.
Conclusion: With the help of OCT, we can differentiate the changes in RNFL thickness in various refractive errors. So, the refractive status of the eye should be kept in mind before making any ocular diagnosis in which the RNFL is a diagnostic criteria.
Keyword :
Spectral domain optical coherence tomography (SD-OCT), Retinal nerve fibre layer (RNFL) thickness, Refractive errors (RE).