Obesity and Glaucoma
Obesity and Glaucoma
Obesity is worldwide health concern today. Statistics show that the numbers of people who are obese are increasing each year. Obesity increases the risk of multiple chronic diseases and conditions such as hypertension, stroke, diabetes mellitus, heart disease, stroke, osteoarthritis and also eye health.
According to Beaver Dam Eye Study, high body mass index (BMI) and obesity is linked to elevated pressure inside the eyes or intraocular pressure. This high intraocular pressure with time can damage visual nerve fibers or optic nerve and cause glaucoma. Optic nerve made from millions of visual nerve fibers that connect the eye to the brain and these fibers transmit electric impulse to the brain. When these nerves are damaged by high intraocular pressure, visual acuity decrease.
There are many risk factors of glaucoma and one of them is obesity. Multiple research studies showed that obesity is an independent risk factor for increased intraocular pressure and there is a positive correlation between Body mass index and intraocular pressure for both men and women.
How obesity can increase the risk of high intraocular pressure:
1- As we all know obesity increases the risk of diabetes mellitus and hypertension and these two comorbidities are established risk factors for high intraocular pressure.
2- Increase in subcutaneous and intraorbital fat tissue. These fat tissues surround the eye causing an increase in episcleral venous pressure or the pressure inside the blood vessels that drain the blood out of the eye and this lead to decrease in outflow facility of aqueous humor. Aqueous humor is a fluid inside the eye. To maintain normal blood pressure, there is a balance between the production and drainage of aqueous humor. Any factor affects this balance will affect the intraocular pressure.
3- An increase in blood viscosity, which reduce the outflow or drainage of aqueous humor from the eye due to increase in the resistance of episcleral veins. Blood viscosity in obese people is high due to an increase in red cell count, hematocrit and hemoglobin.
4- Obesity associated with vascular atherosclerosis which can cause Vascular dysregulation and vasospasms and disturbe the blood flow to the optic nerve head, retina and choroid. Low blood flow to optic nerve will make it more vulnerable to the damage by high intraocular pressure.
5- Obesity is associated with sleep apnea and sleep apnea consider as one of the risk factors for glaucoma.
Weight loss and intraocular pressure
Weight loss is associated with decreased intraocular pressure. One study by the Journal of glaucoma showed a reduction in the average of intraocular pressure after bariatric surgery. Bariatric surgery is surgical procedure performed on obese people to help them to reduce weight.
Another study showed fasting and eating less are associated with decreased intraocular pressure.
Another important thing is that, weight loss can improve vision on patients with glaucoma who use eye drops for glaucoma compared to those who didn’t loss weight.