Ever wonder what causes red eyes with either tobacco or marijuana? Can they have long-term effects on vision? Yes, there are some very serious side effects of both drugs. Here is a breakdown.
The immediate red eye effect is short-term fast acting irritation of the conjunctival membrane from particulate matter. This is only the tip of the iceberg for side effects to our most valuable sense. Longer term eye redness occurs from chronic compromise to the lipid layer of tears. A biochemical reaction with nicotine leaves the outer layer of tears vulnerable to evaporation and dryness triggering more redness.
Cataracts are twice as likely to occur with nicotine users. The insidious drug enters the fragile metabolism of the clear lens and causes clouding much earlier in life than nonsmokers. The risks increase with more frequent use and can improve with those strong enough to quit.
Age related macular degeneration (AMD) a ects the center of the retina, which is responsible for sharp central vision. It can also cause blind spots depending on the location of the circulation damage. Treatment options are improving but still very challenging. Nicotine causes oxidative damage to the blood vessel walls and indirectly affects blood flow to that tissue. Risk factors for AMD are more than twice that of nonsmokers.
Diabetes itself is twice as likely with nicotine users. The effects of diabetes on the eye are even more devastating to the retina. Diabetic retinopathy is the leading cause of blindness to working Americans. This condition is generally caused by bleeding in the back of the eye. However, neovascular problems can occur on the iris, uvea, or vitreous, causing vision loss. Uveitis, in ammation of the middle layer of the eye including the iris, is also twice as likely with tobacco use. It can cause pain to the eye as well as vision loss.
Women who smoke tobacco during pregnancy can transmit the same toxins to the placenta and pass on the negative effects to an unborn child. Another condition, which can be transmitted to the fetus and is backed up with research on tobacco products, is strabismus or crossed eyes.
Marijuana can be even worse for red eyes. THC dilates blood vessels and lowers blood pressure. This causes the conjunctival blood vessels to look red and glassy. It often dilates the pupils and triggers short-term blurred vision. Because of optical aberrations from a large aperture size, vision is not as clear because of the spherical aberration since peripheral light rays have a different focus. Depth of focus and depth of eld are compromised.
There is a myth about marijuana being a cure for glaucoma. It is true that THC lowers the pressure of the eye temporarily, which is usually good for glaucoma. However effective treatment such as eyedrops entail keeping the pressure low continuously. The pressure lowering effects of THC only last about an hour. One would need to take the drug every hour around the clock to equal the effect of one or two glaucoma eye drops. Pot can also lower reaction times, distort vision perception, and impair visual learning.
The good news about tobacco and marijuana effects to the eyes, is they are reversible. Many of the deleterious side effects listed above improve with abstinence. If someone needed one more reason to quit, maybe protecting vision could be that trigger.
Dr. Steve Belanger is the optometrist owner of Peak Vision in Dillon Colorado. He is a 1982 graduate of the Michigan College of Optometry with undergraduate work at Central Michigan University and Michigan State University. Dr. Belanger relocated from Toledo, Ohio to Dillon in 2015 and resides in Keystone full time. His hobbies are skiing, gol ng, cycling, and guitar. Contact Dr. Belanger at (970) 468-6591 or visit peakvision1.com.