A low-cost treatment option for certain eye diseases? Exercise

Noting the $7.5 billion spent on Food and Drug Administration-approved anti-VEGFA drugs between 2013 and 2015, new research suggests a less costly, less invasive option for preventing vision loss in some diseases.

Exercise—noninvasive, patient-controlled and inexpensive.

Recently published in Investigative Ophthalmology & Visual Science, research sheds light on the effect of voluntary exercise on choroidal neovascularization (CNV) in exercising mice. Uncontrolled neovascularization lies behind vision-threatening diseases such as age-related macular degeneration (AMD), corneal neovascularization, glaucoma, diabetic retinopathy and retinopathy of prematurity.

Researchers were affiliated with various entities at the University of Virginia, including the Center for Advanced Vision Sciences; the departments of ophthalmology, medicine, molecular physiology and biological physics, pharmacology, pathology, microbiology immunology and cancer biology and biomedical engineering, plus the Center for Skeletal Muscle Research.

The researchers found:

• In a first study, exercise-trained mice showed a 45% reduction in CNV volume compared to mice that were sedentary.
• In a replication study, the exercise-trained mice showed a 32% reduction in CNV volume.
• Together, the studies showed exercise reduced CNV by 41% reduction.

“Physical activity may be a low-cost, effective and noninvasive treatment option in prevention of a number of eye diseases, including AMD,” the researchers write. “Identifying the molecular mediators that couple physical activity and CNV is an important avenue of research to understand the relationship between this complex modifiable risk factor and retinal disease.” 

Future study was urged by the researchers, who acknowledge the work’s limitations because they induced neovascularization in mice, not humans. 

Healthy eyes 

The study is further evidence that our eye health is linked to overall health, says Fraser Horn, O.D., interim dean, Pacific University College of Optometry in Forest Grove, Oregon. For years, Dr. Horn has worked with amateur and professional athletes. 

“For doctors of optometry, this supports so much of what we do as primary care providers where we look at the person as a whole, not just the eyes or conditions,” Dr. Fraser says. “We ask our patients about habits and lifestyle and there is rationale for why we do this, specifically for systemic conditions and the influence of ocular conditions.  

“Multiple studies show how exercise helps with conditions including, but not limited to, cardiovascular disease, anxiety and depression, IOP and more,” he says. “In addition, there are studies that show how exercise can help with oxidative stress, which we know the eyes get a lot of,” he says. 

Assuming these results are validated in humans, the research raises an additional reason why doctors may need to ask about exercise and promote this lifestyle for patients, Dr. Frazer says. 

“We often look at treatment in a vacuum but imagine if this is synergistic to antioxidant supplements or anti-VEGF injections?” he says. “Imagine if the act of exercise helps with AMD progression. That could really help give our patients another treatment modality. I also think that the interprofessional aspect is key to this as we look at an aging population as well as making sure that the medical team for patients is aware of the recommended exercise, which is always in patients’ best interest.” 

And what do the results mean for patients? 

“While I don’t think exercise will replace anti-VEGF injections, I am really interested to see how this may help supplement the effects of the injections,” Dr. Horn says. “We have some patients who wish they could do more for their AMD and this could give them something tangible to do. It is optimistic, but it would be great if these studies led to mainstream, evidence-based treatments that doctors can promote.”