Perspectives on Glaucoma

Weight loss after bariatric surgery weakly correlated with IOP lowering

Obesity is associated with increased intraocular pressure compared with normal weight controls, and weight loss may have a positive effect, according to researchers in the Journal of Glaucoma.

The prospective case-control study included 25 morbidly obese subjects scheduled for bariatric surgery and 25 age- and sex-matched average weight controls.

IOP measurements were performed in seven positions, three while seated: sitting with head straight, head flexed to 30 degrees and head extended to 30 degrees; and four supine positions: supine flat, right lateral decubitus, left lateral decubitus, and head and upper body elevated at 30 degrees with a wedge pillow.

The second part of the study followed the same obese group 1 to 2 years after bariatric surgery using the same protocol.

Mean age was 43.1 years in the bariatric group and 44.5 years in the control group. Mean body mass index was 49.3 in the bariatric group and 22.7 in the control group.

The mean IOP in the obese group was significantly higher than the control group across each position by a mean difference of 2.5 mm Hg, according to the researchers. No difference was found in mean IOP among the three sitting positions within each group.

Researchers found a significant increase in IOP sitting in supine, right and left lateral decubitus compared with sitting with head straight in both groups.

A total of 19 subjects returned after bariatric surgery with mean time to follow-up of 17 months. Mean weight loss was 49.1 kg, or 36% of total body weight, according to the study.

After bariatric surgery, mean IOP was significantly lower, with a mean difference of 1.6 mm Hg. Right eye mean IOP was significantly lower after bariatric surgery in each position except for the right eye in left lateral decubitus, according to researchers.

Left eye mean IOP was lower after bariatric surgery in each position but only reached statistical significance in the supine head up and right lateral decubitus positions.

Through linear regression researchers concluded that every 10% body weight lost was correlated with a 1.4 mm Hg decrease in IOP in the right eye. Every 10 unit decrease in BMI was correlated with a 2.4 mm Hg decrease in IOP in the right eye.

The researchers concluded, that “...it may be worthwhile to recommend weight loss in overweight glaucoma patients, as IOP remains the only modifiable risk factor.” – by Abigail Sutton

Disclosure: The researchers reported no relevant financial disclosures.

Obesity is associated with increased intraocular pressure compared with normal weight controls, and weight loss may have a positive effect, according to researchers in the Journal of Glaucoma.

The prospective case-control study included 25 morbidly obese subjects scheduled for bariatric surgery and 25 age- and sex-matched average weight controls.

IOP measurements were performed in seven positions, three while seated: sitting with head straight, head flexed to 30 degrees and head extended to 30 degrees; and four supine positions: supine flat, right lateral decubitus, left lateral decubitus, and head and upper body elevated at 30 degrees with a wedge pillow.

The second part of the study followed the same obese group 1 to 2 years after bariatric surgery using the same protocol.

Mean age was 43.1 years in the bariatric group and 44.5 years in the control group. Mean body mass index was 49.3 in the bariatric group and 22.7 in the control group.

The mean IOP in the obese group was significantly higher than the control group across each position by a mean difference of 2.5 mm Hg, according to the researchers. No difference was found in mean IOP among the three sitting positions within each group.

Researchers found a significant increase in IOP sitting in supine, right and left lateral decubitus compared with sitting with head straight in both groups.

A total of 19 subjects returned after bariatric surgery with mean time to follow-up of 17 months. Mean weight loss was 49.1 kg, or 36% of total body weight, according to the study.

After bariatric surgery, mean IOP was significantly lower, with a mean difference of 1.6 mm Hg. Right eye mean IOP was significantly lower after bariatric surgery in each position except for the right eye in left lateral decubitus, according to researchers.

Left eye mean IOP was lower after bariatric surgery in each position but only reached statistical significance in the supine head up and right lateral decubitus positions.

Through linear regression researchers concluded that every 10% body weight lost was correlated with a 1.4 mm Hg decrease in IOP in the right eye. Every 10 unit decrease in BMI was correlated with a 2.4 mm Hg decrease in IOP in the right eye.

The researchers concluded, that “...it may be worthwhile to recommend weight loss in overweight glaucoma patients, as IOP remains the only modifiable risk factor.” – by Abigail Sutton

Disclosure: The researchers reported no relevant financial disclosures.

    Perspective
    Blair Lonsberry

    Blair Lonsberry

    Obesity is on the rise worldwide and is a contributing factor to conditions such as diabetes and hypertension. It has also been linked to increased IOP.

    Obesity is most commonly defined as a body mass index (BMI) of greater than 30 kg/m2 and is proposed to increase IOP by increased episceral venous pressure and decreased aqueous outflow. IOP is also known to increase upwards of 6 mm Hg when going from the seated to supine position.

    In this study, the mean IOP in the obese group was significantly higher than the control group by a mean difference of 2.5 mm Hg, and post-bariatric surgery weight loss decreased IOP by approximately 1.6 mm Hg. The authors report that every 10-unit decrease in BMI results in a 2.4 mm Hg IOP decrease.

    Although the authors did not study glaucoma patients, it stands to reason that prudent practitioners might encourage glaucoma patients to maintain moderate BMI levels. While the evidence supporting this specific recommendation is mixed, weight reduction certainly reduces the risk of cardiovascular disease, which affects the eye and body in many ways.

    Pardon me, but I’m off to the gym to work off the few pounds I gained over the Thanksgiving holiday…

    • Blair Lonsberry, OD, FAAO
    • Pacific University College of Optometry

    Disclosures: Lonsberry is on the speakers bureau for Carl Zeiss Meditec.