Serum levels of vitamin A, visual function and ocular surface after bariatric surgery

Abstract

-Background -Bariatric surgery is the most effective treatment for severe obesity, but the surgery increases the risk of developing nutritional deficiencies, such as vitamin A deficiency. In human metabolism, vitamin A plays a role in vision. Objective -To evaluate serum vitamin A, visual function and ocular surface of patients undergoing bariatric surgery. Methods -A cross-sectional and analytical study was conduced with 28 patients undergoing bariatric surgery for at least 6 months. Ophthalmologic evaluation was done through color vision test, contrast sensitivity test, ocular surface tests and confocal microscopy, as well as vitamin A serum measurement. Results -Vertical sleeve gastrectomy was performed in seven (25.0%) patients and Roux-en-Y gastric by-pass in 21 (75.0%). Mean serum vitamin A level was 1.7±0.5 µmoL/L. Most patients (60.7%) had symptoms of dry eye. Five (17.9%) patients had contrast sensitivity impairment and 18 (64.3%) color vision changes. In the group of patients undergoing Roux-en-Y gastric by-pass, mean vitamin A levels were 1.8±0.6 µmoL/L, whereas they were 1.7±0.5 µmoL/L in patients submitted to the restrictive technique vertical sleeve gastrectomy. The analysis of the influence of serum levels of vitamin A in the visual function and ocular surface was performed by Pearson correlation test and there was no significant correlation between any of the variables and vitamin A. Conclusion -There was no influence of the bariatric surgery technique used on serum vitamin A levels, on the visual function or on the ocular surface. Moreover, there was no correlation between serum levels of vitamin A and the visual function or the ocular surface changes. HEADINGS -Bariatric surgery. Vitamin A deficiency. Night blindness. Xerophthalmia.

Bariatric Surgery in Obesity: Effects on Gut Microbiota and Micronutrient Status

“…Prevalence of vitamin A deficiency following RYGB ranges between 8% and 11% [86]. In a recent study, Brandão et al observed no effects on serum vitamin A concentration or visual function following both RYGB or VSG [158].…”

Relationship of Vitamin A and Thyroid Function in Individuals With Obesity and After Laparoscopic Sleeve Gastrectomy

“…One study pointed out that VAD was uncommon preoperatively (2.7% SG vs. 1.7% RYGB) but increased after surgery (9.4% SG vs. 15.9% RYGB within 1 year post-operation, and 5.2% SG vs. 7.7% RYGB after 1 year) (17). However, another study found that there was no influence of bariatric surgery on serum VA levels (18). Our study found that VA levels were not decreased at 3, 6, and 12 months after LSG but were slightly increased.…”

“…Another study pointed out that VAD was observed in 9.4% of SG and 15.9% of RYGB within 1-year post-operation and 5.2% of SG, and 7.7% of RYGB after 1 year (17). Another study showed no influence of bariatric surgery on serum VA levels (18). As to thyroid function, the consensus view is that LSG may improve thyroid function (19,20).…”

Bariatric surgery—what the ophthalmologist needs to know

“…On the other hand, a cross-sectional study published in 2017 investigated serum vitamin A in 7 post-vertical sleeve gastrectomy patients and 21 post-REY surgery patients [15]. Other than symptoms of dry eye, the study found that mean vitamin A levels were not different between the two groups, and there was no correlation between serum vitamin A levels and ocular effects.…”