Glaucoma is one of the common eye diseases. It is the result of damage to the optic nerve, a vital part for good vision. As this nerve gradually deteriorates, blind spots can further develop in the visual field. Although the cause remains unknown, this nerve damage is strongly related to increased pressure in the eye. Many types of glaucoma might not produce warning signs in an early stage. A change in vision could be noticed when the condition becomes advanced. If left untreated, glaucoma can eventually cause blindness. Since chronic forms of glaucoma can destroy vision before any signs or symptoms are apparent, being aware of risk factors is crucially important. Apart from increasing age, genetic involvements, having had eye injury, one of the major factors is having high internal eye pressure; known as intraocular pressure.
Five warning signs and symptoms of acute glaucoma
The signs and symptoms of glaucoma vary depending on the type and stage. Nonetheless, acute glaucoma usually affects one side of the eyes with presenting single or multiple symptoms including:
- Eye pain
- Eye redness
- Blurred vision
- Tear over-secretion
- Halos around lights
Risk factors of glaucoma
Glaucoma is the result of damage to the optic nerve in which blind spots can further develop in the visual field, leading to impaired vision. There are different forms of glaucoma including primary glaucoma (open-angle glaucoma and closed-angle glaucoma), secondary glaucoma and congenital glaucoma that presents from birth or develops in the first few years of life. Risk factors for glaucoma are:
- Being over age 40. Elderly people are at increased risk to develop glaucoma due to the optic nerve deterioration.
- Having high internal eye pressure (intraocular pressure) greater than 21 millimeters of mercury (mmHg)
- Having a family history of glaucoma especially siblings
- Being extremely nearsighted or farsighted. In people with 100-300 short-sightedness, the risks to develop glaucoma are 2-3 times greater than normal people.
- Taking corticosteroid medications or anti-arthritis agents for a long time
- Having certain medical conditions such as diabetes, heart disease and high blood pressure
Increased eye pressure and glaucoma
Elevated eye pressure is caused due to the buildup of a fluid, called aqueous humor that flows throughout the inside of the eye. This internal fluid normally drains out through a tissue called the trabecular meshwork at the angle where the iris and cornea meet. If fluid is overproduced or the drainage system does not function properly, the fluid cannot be drained out at its normal rate and eye pressure becomes elevated. To measure intraocular pressure, the test is called tonometry. Tonometer is calibrated to measure intraocular pressure in millimeters of mercury (mmHg). If the pressure is greater than 21 mmHg, it significantly increases the risk of optic nerve damage, eventually leading to glaucoma. If left untreated, the damage to the optic nerve causes the blind spot in the visual field, resulting in impaired vision and eventually blindness.
However, increased eye pressure does not necessarily indicate glaucoma. Vice versa, glaucoma, known as normal-tension glaucoma can occur although eye pressure is within the normal range. To screen and early detect glaucoma, a comprehensive eye examination conducted by expert ophthalmologist is highly needed. Tests usually include measuring intraocular pressure, testing for optic nerve damage with a dilated eye examination and imaging tests, checking for areas of vision loss, measuring corneal thickness and inspecting the drainage angle. In addition, some activities might raise internal eye pressure such as diving, weightlifting and wind musical instruments. If abnormal signs and symptoms present, medical assistance must be sought as soon as possible.
Treatment of glaucoma
Although the damage caused by glaucoma is irreversible, regular checkups and treatment help slowing or preventing vision loss, especially if it is caught in its early stages. Glaucoma is treated by lowering the eye pressure. Treatment will be selected depending on symptoms, type and severity. Treatment options include:
- Eyedrops: Eyedrops can help to decrease eye pressure by improving fluid drainage or by decreasing the amount of fluid production.
- Oral medications: If eyedrops alone cannot achieve the desired level of eye pressure, an oral medication might be additionally prescribed.
- Injection medications
- Laser therapy. For open-angle glaucoma, a small laser beam is used to open clogged channels in the trabecular meshwork, therefore improving fluid flow.
- Surgery: Surgery e.g. filtering surgery, draining tube surgery and minimally invasive glaucoma surgery (MIGS) might be considered if other options are not applicable.
If eye pressure is elevated, it is highly recommended to use prescribed medications and follow the appointment plan strictly. Although the damage caused by glaucoma is irreversible, regular checkups and treatment help slowing or preventing vision loss, especially if it is caught in its early stages.
