Obesity and eye health: an important connection to convey to patients

Jeffrey R. Anshel

Public awareness about the overall dangers of obesity is at an all-time high, with television shows such as “The Biggest Loser” and public health initiatives such as First Lady Michelle Obama’s “Let’s Move!” campaign bringing these issues to the forefront. However, despite the general knowledge of obesity’s effects on stroke, heart disease, osteoarthritis and hypertension, it is still the rare patient who is aware of obesity’s impact on eye health.

As patients undertake the difficult business of tackling their 2012 New Year’s resolutions, the optometrist can offer yet another component to their incentive to lose weight. For patients who might have become desensitized to the usual warnings, learning about a potential loss of vision might provide just the jolt of motivation they need.

This patient with proliferative diabetic retinopathy in the left eye had a BMI of 34 kg/m2 and hemoglobin A1C of 12%.

This patient with grade 3 hypertensive retinopathy had a BMI of 35 kg/m2 and blood pressure of 170/115 mm Hg. Images: Pelino CJ

“We don’t always know what will motivate a patient to lose weight,” Hal R. Bohlman, OD, FAAO, a practitioner at James H. Quillen VA Medical Center in Mountain Home, Tenn., told Primary Care Optometry News in an interview. “Many of them aren’t worried about the possibility of heart disease, diabetes or cancer. But when they realize their vision may be at risk, some of them will make a decision to modify their diet and/or fitness habits.”

Concerned but ‘clueless’

Knowledge of the various connections between obesity and ocular health is virtually absent from the public consciousness, according to Jeffrey R. Anshel, OD, FAAO, a private practitioner in Carlsbad, Calif., founding director of the Ocular Nutrition Society (ONS) and PCON Editorial Board member. Dr. Anshel cited a survey conducted by the ONS of more than 1,000 baby boomers on the subject of eye health. He said although the survey respondents ranked their vision as being their most valuable sense and a top health priority, they knew very little about any connection between nutrition and the eye.

This patient with ischemic hemispheric retinal vein occlusion had a BMI of 37 kg/m2, blood pressure of 158/98 mm Hg, no history of diabetes and smoked a pack of cigarettes a day.

This patient with dry AMD had a BMI of 35 kg/m2.

“They said they worried about loss of vision almost as much as heart attack and cancer,” he told PCON, “but as far as knowledge went, they were basically clueless.”

Dr. Bohlman cited an editorial published in the March 2009 issue of Archives of Ophthalmology, which emphasized the importance of patient education regarding obesity and diabetic retinopathy.

“In the editorial, Drs. Gardner and Gabbay state that ophthalmologists could be more effective in the treatment of diabetic retinopathy by emphasizing the systemic factors that affect the development and progression of diabetic retinopathy, rather than new lasers or vitrectomy techniques,” he said. “What they are saying is, we need to be communicating these deadly habits that our patients have, and, in many cases, our patients have the ability to improve their conditions and prognoses for future sight.”

Dr. Anshel agreed that optometrists have the power to do patients a significant service by educating them on eye health and obesity.

“Patients are confused, and they are searching,” he said. “Doctors need to have good answers.”

Defining ‘obese’

“Obesity” is a term used to define an excess of body fat, which is represented in terms of body mass index (BMI), according to Joseph J. Pizzimenti, OD, FAAO, an associate professor at NOVA Southeastern University in Fort Lauderdale, Fla.

According to the National Institutes of Health, BMI is a measure of body fat based on height and weight that applies to men and women.

“In adults, obesity is defined as a BMI of 30 kg/m2 or higher,” Dr. Pizzimenti said in an interview. “It is reasonable to call obesity a disease.”

According to Carlo J. Pelino, OD, FAAO, assistant professor at the Pennsylvania College of Optometry at Salus University in Philadelphia, a distinction should be made between obesity and overweight.

“Overweight is a little bit different. That number (BMI of 25 kg/m² to 29.9 kg/m² ) just means weighing too much,” Dr. Pelino told PCON. “It could be from extra muscle, bone or water, or it could be from too much fat. Whereas obesity pretty much means there is too much body fat.”

Dr. Anshel said obesity is linked to “just about all” of the major ocular conditions.

“We’re finding out that most of the chronic diseases are based on inflammation, and, in America, we have a pro-inflammatory diet,” he said. “There’s close to 60 peer-reviewed studies that link obesity to an increase in these conditions.”

Obesity and cataracts

Dr. Pelino said although cataracts are among the many diseases that are linked to obesity, the precise nature of this connection is not yet fully understood.

“Obesity has been found to be a risk factor in cataracts, but the mechanism is unclear,” he said. “Of the different types of cataracts, cortical cataracts and posterior subcapsular cataracts have been most consistently associated with obesity.”

This 25-year-old female with pseudotumor cerebri had a BMI of 38 kg/m2. She experienced a 78-pound weight gain in the last 8 months and was having headaches and transient visual obscurations.

Dr. Pelino cited findings from the Barbados Eye Study, in which a higher waist-hip ratio was associated with increased incidence of cortical cataracts in African Americans. He said the Blue Mountain Eye Study yielded similar findings.

“This study, which looked at white Australians, suggested that a person with a BMI of more than 30 kg/m² had an increased risk of both cortical and posterior subcapsular cataracts,” he said. “But it’s not understood why.”

Finally, Dr. Pelino referenced findings from the Age-Related Eye Disease Study (AREDS), which found that a high BMI was associated with moderate cortical cataracts.

This correlation is all the more baffling for the fact that an inverse relationship does not seem to exist between cataracts and weight loss.

“There is no evidence that losing weight prevents cataracts,” he said. “So if a person thinks they can stop cataracts by losing weight, that’s not necessarily true. It doesn’t appear to work in the opposite direction.”

Diabetic retinopathy and AMD

While the correlation between cataracts and obesity may still be unclear, other conditions have a more measurable connection.

“The reasons why losing weight can reduce risk are better understood for some conditions than for others,” Dr. Bohlman said.

He said diabetic retinopathy is one condition for which the connection is relatively straightforward.

“Many patients with diabetes can eliminate their need for medications after losing weight and waist circumference, and may also even eliminate the diagnosis of diabetes from their medical problem list,” he said. “Obviously, if they no longer have diabetes, then they have significantly decreased their risk of developing diabetic retinopathy.”

While the relationship of obesity to age-related macular degeneration is somewhat more complex, researchers have put forth credible theories, Dr. Bohlman said.

“Scientists have proposed that adipose tissue competitively absorbs the same nutrients that are necessary for good macular health,” he said. “As adipose tissue in the body decreases, this becomes less of a risk for macular degeneration to develop, and less of a risk to progress once it’s begun.”

Glaucoma: contradictory findings

According to Dr. Pelino, studies have found a relationship between obesity and high intraocular pressure. He cited the Beaver Dam Eye Study, which reported a significantly positive association between elevated IOP and a BMI of more than 30 kg/m2.

“There is evidence of a relationship between obesity and increased IOP, but not necessarily glaucoma,” he said.

While obese patients are more likely to have high IOP, Dr. Bohlman said a study by Gasser found that they were less likely to have glaucoma than those with normal BMI. He noted that the type of tonometry used may make a difference.

Other conditions

Other ocular conditions that have been linked to obesity include floppy lid syndrome, pseudotumor cerebri, exophthalmos, thyroid eye disease and nonarteritic anterior ischemic optic neuropathy.

Dr. Pelino said pseudotumor cerebri, in particular, is a condition that can benefit significantly from a patient losing weight.

“Losing weight is likely to help all of these conditions, but for pseudotumor cerebri, weight gain is the main risk factor, so that will make a big difference,” he said. “If a pseudotumor cerebri patient loses 5% to 10% of their body weight, this is going to help the condition.”

Some other ocular conditions, such as dry eye, have not been directly linked to obesity, but are linked to a healthy diet, Dr. Anshel said.

“Dry eye can be improved through a balance of omega-3 and omega-6 fatty acids,” he said. “By cutting back on junk food, a patient can lower his or her omega-6 intake and help achieve that balance.”

The patient conversation

The first step in overcoming ocular conditions through weight loss is to introduce the topic to the patient. This conversation can be not only uncomfortable to the patient, but often a total surprise in an eye care setting.

“Most patients I talk to are surprised that their eye doctor is talking to them about obesity,” Dr. Bohlman said. “Most have never heard of the ocular complications of their obesity.”

Dr. Pelino emphasized that the topic of obesity is often a sensitive one, and he tries to broach the subject in a nonconfrontational way. He said he begins by asking the patient if they know what BMI is and, if not, he explains it. At this point, rather than telling the patient he or she is obese, he lets the numbers tell the story.

“We have computers in our exam rooms with BMI calculators on them, so I ask patients if I can calculate their BMI for them,” he said. “They will see right away what their number is and whether they are technically overweight or technically obese.”

Dr. Anshel said he offers patients the “Eye on Nutrition” brochure from the ONS, which explains some of the connections between diet and eye health.

“I tell them, “Here is a brochure that talks about how nutrition affects your eyes and, last time I checked, the eyes are a part of the body.’ So I keep it light, but I keep it professional.”

Avoiding judgment

Dr. Bohlman said in discussing obesity with patients, he aims to avoid sounding like yet another scolding voice.

“I want patients to understand that the reason I am bringing this subject up is that I am truly concerned with their health and well-being,” he said. “I want to avoid having them think I am just another doctor who says they are fat and need to lose weight.”

Dr. Pizzimenti said when discussing weight with patients, he chooses the words he uses carefully.

“We as primary eye care providers have a duty to counsel our patients, without stigmatizing our using threatening techniques,” he said. “I use terms like ‘excess weight’ rather than obesity, and ‘physical activity’ rather than exercise.”

Dr. Anshel said there is also one word he tries to avoid in patient discussions.

“People tend to think ‘diet’ is a four-letter word,” he said.

Stating the facts

Providing patients with new – and often surprising – information about the link between their eyes and obesity can often move the conversation from defensiveness and potential insult toward insight and empowerment. Dr. Bohlman said after he has discussed BMI with a patient, he explains the connection between obesity and eye health.

“Most patients have heard of glaucoma, macular degeneration and diabetic retinopathy, so I don’t have to explain those conditions,” he said. “I tell them that these conditions can cause them to lose vision permanently, and that losing weight – especially around the waist – will reduce their risk of losing vision.”

Working with other practitioners

The next step – aiding a patient in implementing a weight loss plan – often calls for cooperation from a patient’s primary care physician or another professional.

“The truth is, nobody can do it alone; everyone needs a coach,” Dr. Anshel said. “I work with a nutritionist locally, and I refer patients to her, and I get reports back. We work together well.”

Dr. Bohlman said he recommends and refers patients to the nutrition service at the hospital where he works.

“However, if I were in private practice, I would certainly dictate a letter to their PCP,” he said. “It not only provides good care for the patient, but it promotes one’s practice within the larger medical community.”

Dr. Pelino said he does send this type of letter to a patient’s primary care doctor.

“I tend to write a detailed letter, explaining that I talked to the patient about BMI and its correlation to eye health,” he said. “It’s also a team approach, so I recommend that they see a dietitian/nutritionist.”

Dr. Pizzimenti sees his role in helping patients maintain a healthy weight as an extension of what the primary care doctor has likely already recommended.

“We strive to reinforce concepts that the patient’s primary care doctor has already introduced, adding that these measures will have a beneficial effect on their eye health and quality of vision,” he said. “On occasion, we’ll refer the patient to a subspecialist or nutritionist/dietitian.”

Looking at underlying causes

Dr. Pelino said he also seeks to understand what may have caused the patient to become overweight.

“In some cases, it may be related to an eating disorder, but I don’t want to assume that,” he said. “Sometimes, patients may gain weight due to systemic conditions such as hypothyroidism, or due to medicines such as birth control, antidepressants or antipsychotics. Or they may have anxiety, or have recently quit smoking. We want, if necessary, to go to their doctor to make sure there aren’t underlying conditions.”

Likewise, Dr. Anshel said the nutritionist he works with approaches various aspects of a patient’s lifestyle when helping them lose weight.

“What she emphasizes is lifestyle enhancement – thinking positively, reducing stress, improving relationships,” he said. “It’s more about lifestyle coaching, rather than just focusing on what they put in their mouths.” — by Jennifer Byrne

References:

• Cumming RG, Mitchell P, Smith W. Diet and cataract: the Blue Mountains Eye Study. Ophthalmology. 2000;107:450-456.
• Gardner TW, Gabbay RA. Diabetes and obesity: A challenge for every ophthalmologist. Arch Ophthalmol. 2009;127(3):328-329.
• Gasser P, Stumpfig D, Schotzau A, et al. Body mass index in glaucoma. J Glaucoma. 1999;8(1):8-11.
• Klein BE, Klein R, Sponsel WE, et al. Prevalence of glaucoma: The Beaver Dam Eye Study. Ophthalmology. 1992;99:1499-1504.
• Leske C, Connel AM, Wu SY, et al. Risk factors for open-angle glaucoma: the Barbados Eye Study. Arch Ophthalmol. 1995;113:918-924.

• Jeffrey R. Anshel, OD, FAAO, practices in Carlsbad, Calif., and is the founder of the Ocular Nutrition Society and a PCON Editorial Board member. He can be reached at 7040 Avenida Encinas, Suite 110, Carlsbad, CA 92011; (760) 931-1390; fax: (760) 944-1200; eyexam@cox.net.
• Hal R. Bohlman, OD, FAAO, practices at the James H. Quillen VA Medical Center in Mountain Home, Tenn. He can be reached at PO Box 4000, Eye Clinic (112E), Mountain Home, TN 37684; (423) 979-3510; fax: (423) 979-3530; Harold.bohlman@va.gov.
• Carlo J. Pelino, OD, FAAO, is an assistant professor at the Pennsylvania College of Optometry at Salus University. He can be reached at 1200 West Godfrey Ave., Philadelphia PA 19141; (215) 276-6180; cpelino@salus.edu.
• Joseph J. Pizzimenti, OD, FAAO, is an associate professor of optometry at NOVA Southeastern University in Fort Lauderdale, Fla. He can be reached at 3200 South University Drive, Fort Lauderdale, FL 33328; (954) 262-1474; fax: (954) 262-1818; pizzisfl@gmail.com.