How doctors of optometry can diagnose a serious vision problem in bariatric-surgery patients

How doctors of optometry can diagnose a serious vision problem in bariatric-surgery patients

"This reaffirms the optometrist's role in the overall health of the patient and the need to correspond with patients' primary care physicians."

Excerpted from the June 2016 edition of AOA Focus, page 56.

It is well known that obesity has been a health issue in the United States for years. More than one in three adults are obese, and more than one in 20 adults are extremely obese, according to the National Institute of Diabetes and Digestive Kidney Diseases.

But what is not well known is that a common method to treat obesity, bariatric surgery, can lead to a serious vision problem: nyctalopia, or night blindness. This is because the most common side effect of bariatric surgery is malnutrition, including decreased levels of fat-soluble vitamins, particularly vitamin A. Vitamin A is necessary for the formation of rhodopsin, the light-sensitive pigment found in rod cells, critical for seeing at night. In fact, night blindness is often the first sign of a deficiency in vitamin A.

Although the complication is rare, given the high number of procedures performed in the U.S., doctors of optometry should be aware of the problem and how to effectively help patients.

Finding the culprit
Brad Lane, O.D., a member of AOA's Health Promotions Committee, and John Dovie, O.D., came across such a case when a 59-year-old patient presented with complaints of difficulty driving at night and trouble seeing objects in poorly lit rooms. The man—who had just been released from the hospital because of a bout of pneumonia—had a history of gastric bypass procedure more than two decades earlier.

Based on the findings of an examination, a diagnosis of nyctalopia was made. "For some reason I just had a feeling that malnutrition was the culprit," says Dr. Lane. "The patient was years post-surgery but was still losing weight."

To confirm the hypothesis, Drs. Lane and Dovie ordered a laboratory analysis. The results showed a severe hypovitaminosis of all fat-soluble vitamins. The patient was referred to his primary care physician for dietary modification and vitamin supplements so vitamin levels could be returned to a safe range.

The patient started a therapy that includes one Ocuvite, vitamin B-12 injections, a multivitamin, fish oil, B-complex and vitamin A. One month after beginning treatment, he reported a marked improvement and a complete recovery is expected. Given the severity of the patient's vision problem, additional intake of dietary sources of vitamin A such as green, leafy vegetables would likely not be sufficient to make up the deficiency, says Dr. Lane.

The optometrist's role
Dr. Lane notes that the patient's surgery was many years ago, when the problem of malabsorption related to the procedure might not have been well understood. Today, the surgery and the follow-up are safer and healthier, and primary care physicians are more aware of complications, he says.

Still, optometrists should be prepared to co-manage bariatric surgery patients, and should watch for possible complications including signs of hypovitaminosis, according to Drs. Lane and Dovie.

"I feel that this reaffirms the optometrist's role in the overall health of the patient and the need to correspond with patients' primary care physicians," says Dr. Lane. "I also feel that it is a reminder that we need to educate patients on the importance of annual eye exams and that many systemic diseases and disorders can reveal themselves through ocular complications."

After his experience with this patient, Dr. Lane says, he always makes a point to instruct patients to have the proper follow-up scheduled with their primary care physician. "And I make sure to discuss the need for appropriate vitamin testing," he says.

June 16, 2016

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