The retinal nerve fiber layer, choroidal thickness, and central macular thickness in morbid obesity: an evaluation using spectral-domain optical coherence tomography

Abstract

Objective: To assess the effect of morbid obesity on retinal nerve fiber layer (RNFL) thickness, central macular thickness (CMT), retinal ganglion cell (RGC), choroidal thickness (CT), central corneal thickness (CCT), and intraocular pressure (IOP).

Patients and methods: Sixty-seven patients defined as having morbid or class III obesity (BMI ≥ 40; Group 1) scheduled to undergo sleeve gastrectomy surgery and 29 nonobese patients (BMI 18.50-24.99; Group 2) underwent complete ophthalmic examination for measurement of IOP, CT, RNFL thickness, CMT, RGC, and CCT. RNFL thickness, CMT, and RGC were measured using spectral-domain optical coherence tomography (SD-OCT). CT measurement was performed using the enhanced depth imaging technique of the SD-OCT. The group data were analyzed and compared using the Mann-Whitney U test and Student's t-test. The relationship between the clinical ocular variables and obesity was analyzed using the Spearman's rank correlation test.

Results: The mean IOP and CCT of Group 1 were found to be significantly higher (p < 0.001) and the mean RNFL, RGC, and CT significantly lower (p < 0.05) than those of Group 2. While Group 2 was found to have a slightly larger cup-to-disc ratio and Group 1 to have a thinner CMT, the differences between Groups 1 and 2 regarding these variables were not found to be statistically significant (p = 0.322 and p = 0.072, respectively). The results of Spearmen correlation analysis indicated the existence of a moderately positive correlation between IOP and BMI (p < 0.001; r = 0.5-0.6).

Conclusions: We have demonstrated by SD-OCT that morbid obesity may have a significant influence on RNFL, RGC, and CT. Morbid obesity may induce inflammatory, hormonal, and metabolic changes.