Glaucoma is a group of eye diseases that can result in vision loss and blindness by harming the optic nerve, a nerve located in the back of the eye. You may not notice the symptoms at first because they can appear gradually. A thorough dilated eye exam is the only way to determine if you have glaucoma.
Symptoms of Glaucoma
Vision blurriness and the perception of rainbow-coloured circles surrounding bright lights are possible symptoms. Usually, both eyes are afflicted, though sometimes one eye may be more severely impacted. Rarely, sudden development of glaucoma can result in severe eye pain.
The majority of those who have open-angle glaucoma exhibit no symptoms. The onset of symptoms is typically late in the course of the illness. Due to this, glaucoma is frequently referred to as the "sneak thief of vision." The primary symptom is typically a loss of peripheral vision.
Angle-closure glaucoma symptoms typically appear sooner and are more pronounced. Damage may occur suddenly. Seek immediate medical attention if you experience any of these symptoms.
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Types of glaucoma and its Causes
There are several types of glaucoma.
The most common type is Primary open angle glaucoma(POAG), which tends to develop slowly over several years.
This kind is caused by the drainage pathways in the eye slowly becoming blocked over time.
Other types of glaucoma include:
Acute angle closure glaucoma(PACG) – an uncommon form brought on by the drainage in the eye suddenly becoming clogged, which can quickly increase the pressure inside the eye.
Secondary glaucoma – Caused by a disease of the eyes that is underlying, like ocular inflammation (uveitis)
Childhood glaucoma (PCG) – a rare kind caused by an anomaly in the eye that only affects very young children.
Exfoliation glaucoma (XFG), also known as pseudoexfoliation glaucoma, is the most prevalent form of open-angle glaucoma that can be recognized globally and affects millions of people. Exfoliation syndrome, a frequent disorder marked by the deposition of white protein-like material on the lens and throughout the fluid drainage system of the eye, as well as tissues all over the body, is the cause of XFG.
Optic nerve injury is the root cause of glaucoma. As this nerve gradually deteriorates, blind spots form in your visual field. For unknown causes, this nerve injury is frequently accompanied by elevated eye pressure. As a rule, glaucoma runs in families. Scientists have identified genes that are connected to some people's excessive eye pressure and optic nerve injury. Currently, it is known that the genes PITX2, PITX3, FOXC1, FOXE3, PAX6, LMX1B, and MAF are linked to PCG.
Genetic factors for POAG include modifications to DNA sequences (around or in genes like caveolin 1 and 2 (CAV1/CAV2), CDKN2B antisense RNA, TMCO1, SIX1/SIX6, and LRP12/ZFPM2 genes), as well as actual DNA loss (TBK1 and GALC). Numerous other genes have also been linked to glaucoma. The genetic variants associated with PACG are in or near PLEKHA7, PCMTD1/ST18, and COL11A1. Gene CNTNAP2 and LOXL1 genetic variations have been linked to XFG.
An accumulation of aqueous humour, a fluid that normally circulates throughout the inside of your eye, is what causes elevated eye pressure. At the angle where the iris and cornea meet, a structure known as the trabecular meshwork serves as the usual drainage pathway for this internal fluid. The drainage tubes get blocked with tiny deposits because of glaucoma. Since the fluid has nowhere to go, it builds up inside the eye. The eye is under pressure from this extra fluid. Glaucoma can develop over time as a result of the optic nerve being damaged by this elevated eye pressure.
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Diagnosis
Regular eye exams are crucial for detecting and treating issues like glaucoma as early as feasible. If an optometrist suspects you have glaucoma following a standard eye exam, they can perform a variety of tests.
Eye pressure test
A device known as a tonometer is used during an eye pressure test (also known as tonometry) to measure the pressure inside your eye.
A tiny amount of an anaesthetic and dye will be injected into the front of your eye by the optometrist. Then they will lightly touch the surface of your eye with the tonometer while shining a light into it. To check the pressure, some optometrists use a separate tool that blows air into the eye without touching it.
Gonioscopy
A gonioscopy is a procedure to examine the front of the eye, specifically the fluid-filled region between the coloured iris and the transparent window (cornea). This is where the drainage from your eye should occur.
Whether this region (the "angle") is open or closed (blocked), which may have an impact on how fluid exits your eye, can be determined with the aid of a gonioscopy. Your optometrist will be informed of the type of glaucoma you have.
Visual field test
A visual field exam, also known as perimetry, looks for blind spots in the field of vision.
You might be asked to click a button to indicate which light spots you can see after being shown a series of them. Your peripheral vision, which is frequently the first part of your eyesight to be impacted by glaucoma, will start to show some dots here and there. If you can't see the dots in the distance, you can have vision loss due to glaucoma.
Optic nerve assessment
It may be assessed to see whether the optic nerve, which connects your eye to your brain, is healthy because glaucoma can cause damage to it. Eye Drops will be used to make your pupils bigger for the exam. Then, your eyes are evaluated utilizing one of:
-an open lamp (a microscope with a bright light)
-optical coherence tomography, which is a form of scan that creates an image of the back of your eye by scanning it with specialized light rays.
Manage and Treatment
Peripheral vision, or what you can see to the side of your head when facing ahead, is typically the first to be affected by glaucoma-related vision loss. Later on, it will have an impact on your central vision, which is essential for daily activities like reading and driving, as well as for clearly viewing objects.
Eye drops, oral medications, surgery, or a combination of treatments are used to treat glaucoma in an effort to lower intraocular pressure and avoid irreversible vision loss. Tell your eye care professional about any adverse effects and take medication as directed. You and your doctor work as a team. Make careful to arrange routine follow-up appointments to continue to check eye pressure if laser or surgical procedures are suggested to lessen the pressure in your eye.
Prevention
You can take a variety of actions to assist safeguard your eyes and reduce your risk of developing glaucoma and losing your eyesight.
Get a thorough dilated eye exam if you belong to a high-risk category to detect glaucoma early and begin treatment. The progression of glaucoma can be halted with prescription eye drops. How frequently you should have follow-up exams will be advised by your ophthalmologist. Medicare provides once-yearly glaucoma screenings for those in high-risk categories.
Getting a thorough dilated eye exam by the age of 40 can help detect glaucoma and other eye disorders early, even if you are not in a high-risk group.
To help preserve your eyes, and theirs, and because open-angle glaucoma is hereditary and has no symptoms, talk to your family members about their vision health.
You can prevent glaucoma-related vision loss by maintaining a healthy weight, managing your blood pressure, engaging in physical activity, and quitting smoking. In addition to preventing type 2 diabetes and other chronic diseases, these are beneficial activities.
Conclusion
Regular eye exams are crucial for detecting and treating issues like glaucoma as early as feasible. Early intervention can prevent serious damage to your vision. Any visual loss that occurred before glaucoma was identified cannot be reversed; however, therapy can slow the progression of your condition.
Glaucoma is typically detected during a routine eye exam, frequently before it manifests any obvious symptoms. Afterwards, more tests are frequently required to identify and track the problem. A minimum of every two years, you should get your eyes checked. You could be advised to get more regular testing if you have a higher chance of developing glaucoma, such as if a close family already has the disease.
You should be referred to a professional eye doctor (ophthalmologist) for additional testing if glaucoma is discovered during an eye exam. They will confirm your diagnosis and determine the extent of the condition's progression as well as the extent of the damage that glaucoma has caused to your eyes. They'll then be able to offer therapy recommendations.
By: Akshitha Sahu
Glossary
PCG( Primary congenital glaucoma) - the most common childhood glaucoma affecting children from birth to age 3 and is a major cause of blindness in this young population.
POAG( Primary open-angle glaucoma ) - A most common type of glaucoma
PACG - ( Primary angle-closure glaucoma ) - is the second most common form of glaucoma that affects over 16 million people globally.
XFG - Exfoliation glaucoma - is the most prevalent form of open-angle glaucoma that can be recognized globally
Ophthalmologist - A specialist in the branch of medicine concerned with the study and treatment of disorders and diseases of the eye.
Peripheral vision - It is the ability to see things where you are not directly looking.
Bibliography
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