Glaucoma: Are you at risk?
I do a lot of glaucoma screenings for people wanting to earn points for their Discovery Vitality or Multiply, but having no idea what the results actually mean. It has also come under my attention that not all glaucoma patients are compliant with using their eye drops prescribed by their ophthalmologist, not understanding exactly what this eye disease entails. I therefore thought it good to write a short article about what glaucoma is and why regular glaucoma screening is important.
Glaucoma is a disorder, usually associated with higher-than-normal pressure inside the eye. It causes damage to the optic nerve that carries information form the eye to the brain. Usually it has few or no initial symptoms, and therefore has also been called the ‘silent thief of sight’. It is also possible to occur when the intraocular pressure is normal. If untreated, it can cause vision loss starting at the sides of your visual field, and eventually can lead to blindness. And because most cases of glaucoma have few or no early symptoms, statistics have shown that about half of Americans with glaucoma don’t know they have it.
The good news is that if glaucoma is detected early, and managed with the correct medical and/or surgical treatment, your eyes can be protected against serious vision loss.
There are two major categories: Open-angle glaucoma (OAG) and narrow angle glaucoma (NAG). The ‘angle’ refers to the drainage angle inside the eye that controls the outflow of the aqueous humor, or watery fluid, that is continually produced inside the eye. In OAG, the aqueous humor can access the drainage angle. In NAG, the drainage angle is blocked and the aqueous humor cannot reach it.
The most common type of glaucoma is Primary open-angle glaucoma. This type gradually reduces your side (peripheral) vision without other symptoms. By the time that it starts to get noticeable, permanent damage has already occurred. If left untreated, and intra-ocular pressure remains high, tunnel vision develops, meaning only objects that are straight ahead can be seen. Ultimately, all vision can be lost, causing blindness.
Acute angle-closure glaucoma produces sudden symptoms such as eye pain, headaches, dilated pupils, halos around lights, red eyes, vision loss, nausea and vomiting. These signs constitute a medical emergency for urgent treatment, as each attack can cause more permanent vision loss.
Glaucoma may also develop as a secondary result of an eye injury, eye infection, inflammation, a tumor or enlarged lens. Glaucoma can also be born with (congenital glaucoma), usually having some or other defect in the drainage system of the eye.
The risk factors include the following:
- Being over age 60
- Being black or Hispanic
- A Family history of glaucoma
- Certain medical conditions, such as diabetes, heart disease, high blood pressure and sickle cell anaemia.
- Certain eye conditions, such as nearsightedness (myopia)
- An eye injury or certain types of eye surgery
- Early estrogen deficiency, e.g. occurring after removal of both ovaries before age 43
- Taking corticosteroid medications, especially eyedrops, for a long time
Diagnosis and treatment
During a routing eye examination, we use a tonometer to measure your intraocular pressure (IOP). An abnormally high IOP reading indicates a problem with the amount of aqueous humor (watery fluid) in the eye. Either the eye is producing too much fluid, or it is not draining properly. A normal IOP reading is below 21 mmHg (millimeters of mercury). If your IOP is higher than 30mmHg, your risk of vision loss from glaucoma is 40 times greater than someone with an intraocular pressure of 15 mmHg.
An ophthalmologist uses different imaging technology to create images of the eye’s optic nerve and other internal structures. They also do visual field tests to determine the extent of vision loss. And lastly they look at the drainage angles of the eye. At specific intervals, additional images and measurements must be taken to make sure that there are no changes that may indicate progressive glaucoma damage.
Usually eye drops aimed at lowering the intra ocular pressures are usually tried first to control the glaucoma. Sometimes glaucoma surgery or laser is necessary, depending on the severity of the disease.
Because glaucoma is often painless, people with the disease may become careless about using their eye drops strictly as prescribed by their ophthalmologist. But it is very important to realise that non-compliance may cause irreversible visual field loss, and can lead to blindness. If you find that your eye drops are uncomfortable, inconvenient, or giving you any side effects, NEVER discontinue them without consulting your ophthalmologist first about a possible alternative.
What can we do to reduce our risk for developing glaucoma?
Researchers in the UK found that maintaining an active lifestyle appears to be an effective way to reduce the risk of developing glaucoma. In addition to this, not smoking, maintaining a healthy weight, and eating a healthy diet have also been noted as reducing the risk.
Regular eye exams are the key to detecting glaucoma early enough to successfully slow or prevent vision loss. The American Academy of Ophthalmology recommends glaucoma screening every four years beginning at age 40 if you don’t have any glaucoma risk factors, and every two years if you’re at high risk or over 65.
We include a glaucoma screening with every eye examination that we do. It is therefore important to come regularly for your eye examinations.
Thank you for reading, I trust that this expanded your knowledge about glaucoma, and that we will see you regularly for your eye examinations. Your eye health is important to us!