What is glaucoma?
Glaucoma is elevated pressure in the eye that can lead to compression and damage to the optic nerve causing loss of vision.
When light enters the eye, it is focused onto on a light-sensitive layer at the back of the eye called the retina. The retina converts these light rays into electrical signals which are carried by the optic nerve to the brain where vision is perceived. Increased pressure within the eye can cause damage to the optic nerve and is usually due to poor drainage of the fluid present within the eye. Drainage occurs through a network of channels in the region where the cornea and iris meet.
What are the causes of glaucoma?
The exact cause of the blockage that occurs in glaucoma is unclear but it may be hereditary. Less commonly it can occur following an injury or infection.
Types of glaucoma:
Open-angle glaucoma: In open-angle glaucoma, no identifiable area of blockage is seen but fluid drainage from the eye is poor. This type of glaucoma occurs more frequently.
Angle closure glaucoma: A narrow angle between the iris and the cornea can limit the drainage of fluid.
Who is at risk of developing glaucoma?
Anyone can get glaucoma however some people are at a greater risk of the disease especially if they have one of the following conditions:
- A family history of glaucoma
- Blood pressure
- Short Sightedness
- Cortisone drug use either past or present (steroids)
- Eye trauma
What are the symptoms of glaucoma?
The loss of vision is gradual and not noticeable initially. Peripheral vision is affected first. Those with an increased risk should be tested regularly as early detection and treatment can minimize vision loss.
How is glaucoma diagnosed?
Your doctor will perform a physical examination of the eyes and evaluate your vision. Eye drops that widen your pupils are placed for the examination. Imaging studies of the optic nerve are obtained. A tonometry test is performed to check the pressure within the eye. Your visual fields are also examined to check peripheral vision.
What if glaucoma goes untreated?
Untreated glaucoma can lead to blindness in a few years.
What are the treatment options for glaucoma?
Glaucoma is generally treated with eyedrops to decrease fluid production or to enhance drainage however, these may cause unwanted side effects. In suitable patients, a gentle, non-tissue destructive laser treatment called Selective Laser Trabeculoplasty (SLT) can be offered that reduces or eliminates the need for eyedrops. Other laser procedures include iridotomy, where a small hole is made in the iris to facilitate fluid flow and cytophotocoagulation, a procedure where a part of the eye is treated to reduce fluid production.
In advanced cases, microsurgery can be performed to control the pressure within the eye. A trabeculotomy involves creation of a new channel for drainage and relief from the pressure.
Prognosis of glaucoma
Early detection is the key to controlling glaucoma. The optic nerve damage and vision loss caused by glaucoma cannot be reversed, but various strategies to lower pressure in the eye can help preserve remaining vision.