Vitamin A Deficiency Causes Eye Problems in Bariatric Surgery Patients
Bariatric surgery patients may require vitamin A supplementation to avoid ophthalmic complications.
Bariatric surgery patients may require vitamin A supplementation to avoid ophthalmic complications, according to findings published in Obesity Surgery.
Researchers from hospitals in Portugal reviewed the limited existing literature to identify the occurrence of eye problems in bariatric surgery patients. First, the investigators categorized bariatric surgery into 3 groups: restrictive, such as adjustable gastric banding (AGB) and gastric sleeve (GS); malabsorptive; and mixed procedures, such as Roux-en-Y gastric bypass (RYGB) and biliopancreatic diversion (BPD), which combine the first 2 procedures.
The current literature acknowledges that bariatric surgery patients are at risk for the following postoperative deficiencies: vitamins B12, B1,C, folate, A, D, E, and K, along with minerals iron, selenium, zinc, and copper. Of those, vitamins A, E, B1, and copper deficiencies can impact optic function, the researchers noted.
The authors highlighted that vitamin A is essential to human life function, but in the eye, it is vital for ocular metabolism. Processes include maintenance of the conjunctival and corneal epithelial surfaces, retinal phototransduction, and retinal pigment epithelial viability. While vitamin A deficiency is difficult to diagnose, it is manifested in a predictable sequence: nyctalopia (night blindness), conjunctival xerosis with Bitot’s spots, corneal xerosis, corneal ulceration, and localized or complete limbal to limbal corneal dissolution, known as keratomalacia.
Studies that have observed vitamin A deficiency in bariatric surgery patients are limited at best, and their results are inconsistent, the researchers noted. Furthermore, the deficiency depends on the type of bariatric surgery. With RYGB, 1 study found a vitamin A deficiency in 35% of patients at 6 weeks follow-up after surgery and 18% after 12 months. Another study found vitamin A deficiency in 11% of patients 1 year after RYGB and 8.3% after 2 years.
Vitamin A deficiency appears to be more prevalent among BPD patients. For instance, 1 study found 52% of BPD patients had a deficiency 1 year after the procedure and 69% of patients had it 4 years after the surgery. The patients often reported compliance with supplements, which the researchers believed emphasized a possible need for parenteral supplementation of vitamin A in some cases.
In restrictive bariatric surgeries, such as AGB and GS, there appeared to be no statistically significant difference in vitamin A deficiency prevalence between the AGB group and the control group. The researchers said this might suggest that there is no increased risk of deficiency after restrictive bariatric surgeries.
The researchers found recent publications that commented on vitamin E deficiency affecting the retina and causing pigmentary retinopathy; however, it is not the most common indicator. Vitamin E deficiencies generally manifest in polyneuropathy, which has symptoms of areflexia, cerebellar ataxia, loss of position sense, loss of vibration sense, and muscle weakness.
Vitamin B1, or thiamine, deficiencies can also impact ophthalmic functions, causing nystagmus and opthalmoplegia. These symptoms can be part of Wernicke’s encephalopathy, which also includes ataxia and confusion.
Copper deficiencies affect the optic nerve rarely, but cause optic neuropathy, myelopathy, or myeloneuropathy. All of these symptoms can indicate subacute gait disorder with prominent sensory ataxia and/or spasticity.