Last updated on June 9th, 2017 at 03:06 pm
Glaucoma refers to a group of related eye conditions that cause damage to the optic nerve that brings information from the eye to the brain. Glaucoma generally has couple of or no initial symptoms.
In many cases, glaucoma is associated with higher-than-normal pressure inside the eye– a condition called ocular hypertension. But it likewise can occur when intraocular pressure (IOP) is normal. If neglected or uncontrolled, glaucoma first causes peripheral vision loss and eventually can lead to loss of sight.
According to the American Academy of Ophthalmology, the most typical kind of glaucoma– called primary open-angle glaucoma– impacts an estimated 2.2 million people in the United States, which number is anticipated to increase to 3.3 million by 2020 as the U.S. population ages.
And due to the fact that a lot of cases of glaucoma have few or no early symptoms, about half of Americans with glaucoma do not know they have it.
Glaucoma is the second-leading reason for blindness in the United States (behind macular degeneration), and the second-leading cause of blindness around the world (behind cataracts).
Types Of Glaucoma
The two significant classifications of glaucoma are open-angle glaucoma (OAG) and narrow angle glaucoma. The “angle” in both cases describes the drainage angle inside the eye that manages the outflow of the watery fluid (aqueous) that is continually being produced inside the eye.
If the aqueous can access the drain angle, the glaucoma is called open angle glaucoma. If the drainage angle is blocked and the liquid can not reach it, the glaucoma is called narrow angle glaucoma.
Variations of OAG include: primary open angle glaucoma (POAG), normal-tension glaucoma (NTG), pigmentary glaucoma, pseudoexfoliation glaucoma, secondary glaucoma and hereditary glaucoma.
Variations of narrow angle glaucoma consist of consist of severe angle closure glaucoma, chronic angle closure glaucoma, and neovascular glaucoma.
- Main open-angle glaucoma. This typical type of glaucoma gradually minimizes your peripheral vision without other symptoms. By the time you observe it, long-term damage already has occurred.
If your IOP remains high, the damage triggered by POAG can advance till tunnel vision develops, and you will be able to see just objects that are straight ahead. Eventually, all vision can be lost, triggering loss of sight.
- Intense angle-closure glaucoma. Likewise called narrow-angle glaucoma, intense angle-closure glaucoma produces sudden symptoms such as eye pain, headaches, halos around lights, dilated students, vision loss, red eyes, nausea and vomiting.
These signs make up a medical emergency situation. The attack may last for a couple of hours, then return once again for another round, or it may be constant without relief. Each attack can cause progressively more vision loss.
- Normal-tension glaucoma. Like POAG, normal-tension glaucoma (likewise called normal-pressure glaucoma, low-tension glaucoma or low-pressure glaucoma) is a kind of open-angle glaucoma that can cause visual field loss due to optic nerve damage. But in normal-tension glaucoma, the eye’s IOP stays in the normal range.
Likewise, pain is not likely and long-term damage to the eye’s optic nerve may not be noticed till symptoms such as one-track mind happen.
The reason for normal-tension glaucoma is unknowned. But numerous medical professionals think it belongs to poor blood flow to the optic nerve. Normal-tension glaucoma is more typical in those who are Japanese, are female and/or have a history of vascular disease.
- Pigmentary glaucoma. This rare kind of glaucoma is caused by clogging of the drainage angle of the eye by pigment that has actually broken out from the iris, decreasing the rate of aqueous outflow from the eye. In time, an inflammatory reaction to the blocked angle harms the drainage system.
You are unlikely to notice any symptoms with pigmentary glaucoma, though some pain and blurry vision may take place after workout. Pigmentary glaucoma most regularly impacts white males in their mid-30s to mid-40s.
- Secondary glaucoma. Symptoms of chronic glaucoma following an eye injury might show secondary glaucoma, which also may establish with existence of eye infection, swelling, a tumor or enlargement of the lens due to a cataract.
- Genetic glaucoma. This acquired type of glaucoma exists at birth, with 80 percent of cases detected by age one. These children are born with narrow angles or some other defect in the drain system of the eye.
It’s difficult to spot signs of genetic glaucoma, due to the fact that children are too young to comprehend what is taking place to them. If you observe a cloudy, white, hazy, bigger or protruding eye in your child, consult your eye doctor. Genetic glaucoma normally occurs more in kids than in girls.
Who Is At Risk to Get Glaucoma?
Open-angle glaucoma is 3 times most likely to affect African-Americans, compared with non-Hispanic whites in the United States, and loss of sight from glaucoma is at least six times more widespread among African-Americans than non-Hispanic whites.
Studies also suggest open-angle glaucoma affects Hispanics and Latinos at comparable rates to African-Americans.
And in a study released in 2014 that compared the frequency of two types of open-angle glaucoma– main open-angle glaucoma (POAG) and normal-tension glaucoma (NTG)– amongst Filipino and white Americans age 40 and older, researchers found Filipino Americans were more commonly detected with both types of open-angle glaucoma than white Americans (11.9 vs 8.2 percent for POAG; 6.8 vs. 2.5 percent for NTG).
Also, amongst Filipino Americans detected with open-angle glaucoma, 46.7 percent had the normal-tension range, whereas only 26.8 percent of whites with open-angle glaucoma had NTG, which can be more challenging to treat than POAG.
Glaucoma typically is called the “quiet burglar of sight,” because many types usually cause no pain and produce no symptoms until visible vision loss occurs.
For this factor, glaucoma typically advances undetected until the optic nerve already has been irreversibly damaged, with varying degrees of long-term vision loss.
But with acute angle-closure glaucoma, symptoms that occur all of a sudden can consist of blurred vision, halos around lights, intense eye pain, queasiness and vomiting. If you have these symptoms, make sure you see an eye care practitioner or go to the emergency room immediately so steps can be taken to prevent long-term vision loss.
Diagnosis, Screening And Tests For Glaucoma
During routine eye tests, a tonometer is used to determine your intraocular pressure, or IOP. Your eye typically is numbed with eye drops, and a little probe carefully rests against your eye’s surface. Other tonometers send out a puff of air onto your eye’s surface area.
An unusually high IOP reading indicates a problem with the quantity of fluid (aqueous humor) in the eye. Either the eye is producing too much fluid, or it’s not draining appropriately.
Generally, IOP needs to be below 21 mmHg (millimeters of mercury) – a system of measurement based on how much force is exerted within a certain defined area.
If your IOP is higher than 30 mmHg, your risk of vision loss from glaucoma is 40 times greater than someone with intraocular pressure of 15 mmHg or lower. This is why glaucoma treatments such as eye drops are developed to keep IOP low.
Other methods of keeping an eye on glaucoma involve the use of advanced imaging technology– such as scanning laser polarimetry (SLP), optical coherence tomography (OCT) and confocal scanning laser ophthalmoscopy– to develop baseline images and measurements of the eye’s optic nerve and internal structures.
Then, at defined periods, extra images and measurements are taken to make certain no modifications have actually taken place in time that might show progressive glaucoma damage.
Visual field testing is a way for your eye doctor to figure out if you are experiencing vision loss from glaucoma. Visual field testing involves staring directly ahead into a device and clicking a button when you discover a blinking light in your peripheral vision. The visual field test may be duplicated at regular periods to make sure you are not establishing blind spots from damage to the optic nerve or to identify the level or development of vision loss from glaucoma.
Gonioscopy likewise might be performed to make sure the aqueous humor (or “aqueous”) can drain pipes freely from the eye. In gonioscopy, special lenses are used with a biomicroscope to allow your eye doctor to see the structure inside the eye (called the drainage angle) that controls the outflow of liquid and therefore affects intraocular pressure. Ultrasound biomicroscopy is another technique that may be used to assess the drain angle.
Treatment can involve glaucoma surgery, lasers or medication, depending on the severity. Eye drops with medication focused on decreasing IOP typically are attempted first to control glaucoma.
Because glaucoma often is painless, people may end up being reckless about strict use of eye drops that can control eye pressure and help prevent irreversible eye damage.
In truth, non-compliance with a program of prescribed glaucoma medication is a major factor for blindness caused by glaucoma.
If you discover that the eye drops you are using for glaucoma are uneasy or inconvenient, never ever discontinue them without first consulting your optometrist about a possible option therapy.
Can you decrease your risk for glaucoma? According to a current European study, workout might work for some people.
Scientists in the U.K. found that greater levels of physical exercise appear to provide a long-lasting benefit of minimizing the occurrence of low ocular perfusion pressure (OPP), an essential risk factor for glaucoma. OPP is a mathematical value that is computed using a person’s intraocular pressure and his or her blood pressure.
The outcomes revealed that research study individuals who engaged in moderate exercise around 15 years prior to the study had a 25 percent decreased risk of low OPP that could cause glaucoma.
“It appears that OPP is mostly figured out by cardiovascular fitness,” said research study author Paul J. Foster, MD, PhD, of the University College London Institute of Ophthalmology. “We can not discuss the cause, however there is definitely an association in between an inactive lifestyle and factors which increase glaucoma risk.”
Maintaining an active lifestyle seems a reliable method for people to lower their risk of glaucoma and lots of other serious health problems, Dr. Foster concluded.
In addition to regular workout and an active lifestyle, you likewise can minimize your risk for glaucoma by not cigarette smoking, preserving a healthy weight, and consuming a different and healthy diet.