Cataracts and glaucoma are common eye conditions that are often confused by non-clinicians. In the brief video below, optometrist Joseph J. Allen, O.D., FAAO, Diplo ABO, known on YouTube as Doctor Eye Health, explains the basics of cataracts and glaucoma, so you know what to look for and when to get immediate medical assistance.*

https://www.youtube.com/shorts/XA_-2z9cuao

Cataracts versus glaucoma

Cataracts and glaucoma are probably confused with each other the most, Allen says, but though they often occur together, the conditions are quite different.

• In cataracts, an eye lens that was once clear becomes opaque or cloudy, and vision is obscured.
• In glaucoma, the optic nerve slowly deteriorates, often due to increased eye fluid pressure on the nerve.

Pressure on the nerve can cause gradual loss of peripheral (side) vision, ultimately leading to irreversible blindness.

Symptom comparison

Glaucoma symptoms depend on the type of glaucoma you have. 

Common symptoms of open-angle glaucoma include:

• Blind spots in peripheral vision first, then central vision (often in both eyes)
• Tunnel vision (loss of peripheral vision)
• Blurred vision

Closed-angle glaucoma is a medical emergency and can have a rapid and painful onset. Symptoms can include:

• Eye pain and redness
• Severe headaches
• Nausea and vomiting
• Tunnel and blurred vision
• Seeing halos around lights

Cataract symptoms typically include:

• Faded colors
• Blurred, clouded, and/or double vision
• Poor night vision
• Frequent eyeglass prescription changes
• Light sensitivity (lights seeming too bright)

Treatment comparison

Glaucoma can become worse if left untreated and eventually lead to irreparable blindness, but consistent treatment can help prevent vision loss and slow disease progress. Treatment to lower eye pressure must begin early on, which underscores the importance of regular eye exams to detect glaucoma as soon as possible.

• First-line treatment is usually eye drops, which lower eye pressure by either improving eye fluid drainage or decreasing eye fluid production. 
  • If eye drops do not adequately lower eye pressure, they can be combined with oral medications.
• Secondary treatment options for lowering eye pressure are laser and surgery. 
  • Laser therapy improves fluid drainage and can be effective when eye drops fail or can’t be tolerated, though it can take time to see its full effect. 
  • Filtering surgery commonly happens with a small opening being made in the sclera (white part of the eye) to release fluid buildup, called a trabeculectomy.
• Closed-angle glaucoma requires immediate attention to lower eye pressure.
  • Treatment is with surgery, medicines, and laser therapy, such as laser peripheral iridotomy, in which a small hole is made in the iris to release fluid buildup.

Cataracts form from the breakdown of eye proteins that clump together to cloud vision. Cataracts can lead to blindness if left untreated. If prescription glasses aren’t effective, surgery is the only other option. 

• People are advised to speak to their eye doctor since many are able to wait until their cataracts affect daily tasks, as cataracts typically don’t affect eye health.
• Cataracts can also form following glaucoma surgery, but people may be advised to wait one-two years to have them removed to be sure their eye is stable.

The new artificial lens is a permanent substitution for the clouded natural lens. If an artificial lens can’t be used, cataracts can be removed and then vision corrected with contact lenses or glasses.

Cataracts can impact glaucoma, but surgeries can be combined

A cataract can become big enough to block eye fluid drainage, requiring treatment similar to glaucoma. 

• Glaucoma and cataract surgery can sometimes be combined using only one incision. 
• Cataract surgery by itself can sometimes improve fluid drainage and lower eye pressure, eliminating the need for glaucoma surgery.

Not everyone is a candidate for combination surgery. Speak with your ophthalmologist about all your options.

*Doctor Eye Health. (2022, May 3). Cataracts vs Glaucoma – What’s the Difference? [Video file]. YouTube. Retrieved from https://www.youtube.com/shorts/XA_-2z9cuao