5th of September 2022

How to Differentiate Between Cataract & Glaucoma

Cataracts and glaucoma are common eye conditions that increase with age. They are quite different, but in some ways influence one another.

A cataract occurs when the nature lens inside the eye becomes cloudy, obscuring the clarity of vision. Each of our eyes has a natural lens which focuses light onto our retina. When we are born it is crystal clear, but as we age it slowly acquires opacity. This process continues to a point, generally when we are older, where the opacity noticeably affects our vision. Often the first symptoms of cataract are an increased need to update one’s spectacles more frequently, due to a hardening of the lens and change in refractive power. They can cause glare, especially at dusk or with oncoming headlights when driving. They can make reading difficult, especially at night when increased lighting is needed. Cataracts are best detected when your eyes are examined by your Optometrist or Ophthalmologist. Eventually they become sufficiently bothersome to require cataract surgery. In cataract surgery, the cataract is removed from its bag and a clear, artificial intraocular lens is inserted in its place. 

The technology behind these intraocular lenses has improved dramatically over the past few years. Intraocular lenses are often yellow tinted to protect the eyes from harmful, incoming ultraviolet light. They can be carefully shaped and positioned to correct astigmatism as well as general refractive error to allow people to see well in the distance without glasses; often reading glasses are still required for near work. Better still, newer options, such as Extended Depth of Focus lenses, allow greater independence from glasses for much near and intermediate-distance activities. To find out more, book an appointment with A/Prof Skalicky to discuss.

There is usually no urgency in cataract surgery – the surgery can be delayed several months until the time suits you to have the surgery. However sometimes the cataracts can cause other problems in the eyes, such as narrowing of the eye’s drainage angles and glaucoma – in these cases it is best to have them removed soon.

Glaucoma occurs when pressure in the eye damages the nerve that connects the eye to the brain; the optic nerve. Without this nerve we cannot see. In glaucoma, the optic nerve is damaged in a slow, piecemeal way; since the process is painless, and tends to affect our peripheral vision first (which we are generally unaware of), we may not notice glaucoma until it is advanced. Once damage occurs it cannot be reversed; but treatment (generally involving lowering eye pressure) can prevent or halt the damage from worsening. That is why it is always best to diagnose glaucoma as early as possible. 

Glaucoma is generally detected on routine assessment at an Optometrist or Optician’s practice. Although people generally visit an Optometrist for assessment of eye discomfort or need for spectacles, a good Optometrist will also check the patient for signs of common eye conditions like glaucoma. If there are suspicious signs (such as narrow drainage angles or changes of the optic nerve) then the patient will be referred to an Ophthalmologist for further assessment. Clinical diagnosis is supported by a test of peripheral vision (visual field test) and a scan of the optic nerve. 

Glaucoma is a lifelong condition that requires lifelong monitoring and treatment. It is generally treated by lowering the eye pressure with gentle, safe laser; regular eye drops; or in some cases glaucoma surgery.