Changes in Ocular Functions after Bariatric Surgery: A Cross-sectional Study

Introduction: Obesity is a critical problem worldwide, as it contributes to many pathological diseases. Therefore, Bariatric Surgery (BS) is considered an optimal treatment modality for achieving ideal weight. However, the eye and its functions can be affected after surgery due to the changes that occur throughout the body. Aim: To investigate and analyse visual functions following BS. Materials and Methods: This was a cross-sectional study conducted at Elite Hospital in Riyadh City, Saudi Arabia, from January 2023 to June 2023. A total of 16 subjects (32 eyes) were enrolled in the study. The subjects were categorised into three groups: preoperative BS (Group I), postoperative six months (Group II), and postoperative duration of one to two years (Group III). All participants underwent complete ophthalmological examinations, including Visual Acuity (VA) measurement using the Snellen chart, refractive error measurement by autorefractometer, colour vision testing using the Ishihara test, Intraocular Pressure (IOP) measurement, and anterior segment examination using a slit lamp. Additionally, a dryness assessment was performed using clinical tests. Finally, choroidal thickness and Retinal Nerve Fiber Layer (RNFL) measurements were obtained using Optical Coherence Tomography (OCT). Statistical analysis was performed using IBM Statistical Package for Social Sciences (SPSS) Software Grad Pack Base version 28.0. One-way Analysis of Variance (ANOVA) and Kruskal-Wallis tests were used to compare the mean values of the three groups. Post-hoc tests were employed for multiple comparisons between groups. The significance level was set at 5%. Results: The range of the participants' ages was 24 to 47 years. It was revealed that Body Mass Index (BMI) was significantly influenced by the time elapsed since BS (p-value=0.04). In contrast, the effect of BS was not statistically significant between groups for both systolic and diastolic measurements (p-value>0.05). Moreover, the automated Central Foveal Thickness (CFT) showed a statistically significant difference between groups, with p-values of 0.013 for the right eye (OD) and 0.016 for the left eye (OS). Although there was no statistical difference in the effect of BS on the OD Ganglion Cell Complex (GCC) (p-value=0.338), there was a significant effect on the OS GCC (p-value=0.03). Post-hoc analysis indicated that participants in Group I had a higher BMI than participants in Group III, with a p-value of 0.036. CFT was significantly increased in Group II OS compared to Group I (p-value=0.016). Group III showed a significantly higher GCC than Group II (p-value=0.028). There was a significant difference in Goldmann IOP among the three groups (p-value=0.009). Additionally, a negative correlation was found between the duration of BS and BMI (r=-0.615, p-value=0.011) as well as for systolic measurements (r=-0.592, p-value=0.016). A strong negative correlation was also observed between Goldmann IOP and BS, which was statistically significant for the OD (r=-0.788*, p-value<0.001) but not for the OS (r=-0.346, p-value=0.189). There was a statistically significant difference in OD nasal choroidal thickness at 500 mu m (p-value=0.03) and at 1000 mu m (p-value=0.03) among the three groups. Conclusion: Hence, it can be concluded that some ocular functions were positively altered while others were negatively affected after BS. Choroidal thickness decreased in the six-month postsurgery group but increased in the one to two-year group. IOP decreased in the six-month postsurgery group and further decreased in the one to two-year group. CFT increased in the sixmonth group but decreased in the one to two-year postoperation group. GCC thickness decreased in the six-month group and increased in the one to two-year post-BS group. Measurement of such parameters could serve as a preoperative assessment, especially for glaucomatous and hypertensive individuals who are planning for future BS. These evaluations could also aid in the treatment of eye diseases after surgery. Additionally, normal individuals should undergo pre- and postoperative evaluations of their visual refraction, as this may be altered due to changes in posterior segment parameters, such as choroidal thickness. However, more studies are needed to validate these results.