- Vision & Eye Care
Glaucoma - Understanding the Silent Thief of Sight
How the Unafflicted Eye Works
Inside the front of the normal eye, there is a constant inflow and outflow of a clear, nourishing fluid called aqueous humor.
This fluid drains back into your body’s circulation, flowing from the Ciliary body, behind the iris, through the pupil, and out a drainage area called the Trabecular Meshwork.
This flow maintains a relatively constant eye pressure - the repeated use of flame to keep a hot air balloon inflated. This constant pressure keeps the eye firm, and also helps to properly bend light entering the eye.
Open Angled Glaucoma
In the most common type of glaucoma - the open angle type - the nourishing aqueous fluid cannot properly drain. Much like a damned river, continued inflow of the fluid increases the eye’s intraocular pressure (much like over-filling a balloon with air.
This greater-than-normal pressure can damage the eye’s optic nerve, resulting in a loss of vision over time. The shape of the eye can also be changed, altering vision, and requiring the use of glasses.
Damage to the optic nerve usually causes loss of side vision first, followed by critical central vision. This process is slow, and a loss of vision at the periphery often goes unnoticed for long periods.
Untreated, open angled Glaucoma can cause total blindness.
Closed Angle Glaucoma
With closed angle glaucoma, aqueous fluid outflow may be blocked at the pupil, causing a more sudden increase in eye pressure. The iris may move forward to block the drain area, radically altering vision for the worse.
While this type of glaucoma is more sudden, it never the less often goes unnoticed and worsens over time.
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Glaucoma is detected in several ways, often requiring many tests to diagnose.
In one such test, a light puff of air hits the eye. As the air indents the front of the eye, a machine measures the size of the reflected light ring. This detects any above average change in ocular pressure.
The drainage area is also examined using a contact lens with mirror. A similar inspection includes the use of a slit lamp, which highlights the angle drainage area.
A doctor can also test your field of vision for any slight loss or change to vision.
Most treatments simply attempt to reduce the eye’s pressure. In most cases, medication of daily eye drops can control glaucoma. To be effective, however, medication must be used consistently and as directed.
For pupillary block glaucoma, a laser can be used to create a hole in the iris, to allow aqueous pressure outflow. Lasers are also used for other glaucomas, directly treating the trabeculum, which medication can sometimes fail to control.
In some extreme cases, however, surgery is used in difficult cases.
During the surgery, a section of the outflow area is removed. Next, a controlled aqueous outflow can occur as a small filtering bleb.
A derivative filtering surgery places a small collagen implant, to assist outflow over time.
A valve implant can be used to control aqueous outflow, for maintaining proper eye pressure.
Glaucoma may lead to blindness if not diagnosed and treated early. Glaucoma can steal your vision without notice, so regular check-ups are important in detecting early signs.
Some higher risk groups include people over 35 years of age, diabetics, African-Americans, those with high degrees of nearsightedness, and those with a family history of glaucoma.
To be effective in preventing the progressive damage glaucoma can cause to your vision, medications must be used consistently and as directed. Any changes to your vision should be brought to your Doctor’s attention immediately.
* Do not treat this article as medical fact. Consult a doctor for further information and questions.
Matthew Gordon is the author of & The Thin Blue Line: An In-Depth Look at the Policing Practices of the Los Angeles Police Department. To Live, To Think, To Hope - Inspirational Quotes by Helen Keller
© Matthew Gordon, 2011