[Biology Class Notes] on Glaucoma Pdf for EXAM [2024]

Glaucoma is the name given to a collection of disorders that result in visual field loss due to a specific type of optic neuropathy (i.e. optic nerve disease or abnormalities). In glaucoma disease, Increased intraocular pressure is one of the numerous key risk factors for glaucoma development. However, no single pressure is symptomatic of the condition. At different eye pressures, the sensitivity of an individual’s optic nerve and the retinal cells whose fibres make up the optic nerve called the ganglion cells to damage varies greatly. A normal eye pressure range is between 10 and 21 mm (0.4 and 0.82 inches) of mercury, although persons with pressures below 21 mm can develop glaucoma eye (normal-tension glaucoma, or low-tension glaucoma). Due to this very reason, glaucoma can also be referred to as eye pressure disease.

Glaucoma Disease Symptoms

Symptoms of glaucoma in the eyes can be minimal to severe depending on the affected individual and it may increase and get worse with time when untreated.

Blind patches in your peripheral (side) or central vision, often in both eyes
Advanced phases of tunnel vision in the later stages of glaucoma eye disease
Headache that is severe
Pain in the eyes in the glaucoma eye disease is severe and will devoid you the focus in any kind of daily activities
Vomiting and nausea
Vision becomes hazy
Lights with halo effects are seen
Redness in the eyes

Causes of Glaucoma Disease

The exact cause is still unknown and as of writing the doctors and experts suggest that many factors contribute to glaucoma eye disease.

high or increased blood pressure
dilating eye drops
blocked or restricted drainage in the eye
drugs, such as corticosteroids
poor or diminished blood flow to the optic nerve

Types of Glaucoma Disease

The pace of aqueous humour generation by the ciliary body and the barrier to outflow through various channels influence a person’s ocular pressure and eye pressure range. Primary open-angle glaucoma (POAG) and angle-closure glaucoma are the two main types of glaucoma. And even though the age group that is most affected by glaucoma is above 40 years of age the symptoms can start as early as birth due to conditions unknown and there have been many research studies that state that it can take years to actually define and distinguish its cause and treatment as it is associated with the optic nerve that is a part of the eye and the central nervous system as well.

Glaucoma Types	Meaning	Treatment
Primary Glaucoma	Primary glaucoma, often known as chronic glaucoma, is a kind of glaucoma. Intraocular pressure, or excess pressure in the eye, causes it. This rise in pressure is usually caused by a blockage in the drainage system of the eye. As a result, pressure rises, potentially damaging the visual nerve.	POAG (primary open-angle glaucoma) is the main cause of blindness for which there is currently no cure. Current classes of medicines, such as prostaglandin analogues, beta-blockers, alpha-agonists, and carbonic anhydrase inhibitors, are used to lower intraocular pressure (IOP).
Open-Angle Glaucoma	The most prevalent type of glaucoma is open-angle glaucoma. The trabecular meshwork is partially occluded, yet the drainage angle formed by the cornea and iris remains open. As a result, the pressure in the eye steadily rises. The optic nerve is harmed by this pressure.	Medication (typically eye drops), laser trabeculoplasty (a procedure that increases the drainage of eye fluid through the spongy tissue around the cornea called the trabecular meshwork), and surgery are all options for open-angle glaucoma treatment.
Angle-closure glaucoma	Angle-closure glaucoma, also known as closed-angle glaucoma, is a condition in which the iris bulges forward, narrowing or blocking the drainage angle created by the cornea and iris. Fluid cannot circulate through the eye as a result, and pressure rises.	acetazolamide, a drug that decreases the amount of fluid in your eyes. beta-blockers, which reduce the amount of fluid produced by the eye. steroids, which are anti-inflammatories Nausea and vomiting are treated with painkillers (as a comfort measure). pilocarpine, a drug that widens the gap between your iris and cornea.
Secondary Glaucoma	Secondary glaucoma eye disease is any type of glaucoma in which the reason for increased eye pressure can be identified, resulting in optic nerve injury and vision loss. Secondary glaucoma is like primary glaucoma which can lead to open-angle glaucoma or angle-closure glaucoma. And the affecting area can be one eye or both eyes.	An eye injury, inflammation, certain medicines like steroids, and advanced cases of cataract or diabetes can all induce secondary glaucoma. Treatment options will vary depending on the underlying problem, but they typically involve medicines, laser surgery, or traditional surgery.
Childhood Glaucoma	Childhood glaucoma, also known as congenital glaucoma, paediatric glaucoma, or infantile glaucoma, affects infants and children. It is most commonly detected in the first year of life. This is an uncommon genetic disorder caused by improper development of the eye’s drainage system before birth.	The intraocular pressure (IOP) of children with glaucoma is reduced using medicinal and/or surgical methods. Surgery is used to treat most cases of primary paediatric glaucoma. The most common surgical procedures are trabeculectomy and goniotomy, which open the drainage canals.

Risk Factors of Glaucoma

Age is a Factor- Glaucoma is more common in people over 60, according to the NEI which is a trustable source, and the risk of glaucoma increases slightly with each year of age. If you’re African-American, your risk begins to rise at the age of 40.
Race and Ethnicity- African-Americans and people of African heritage are much more likely than Caucasians to acquire glaucoma. People of Asian ancestry are more vulnerable.
Problems with the Eyes- Increased eye pressure can be caused by chronic eye inflammation and weak corneas. Eye pressure can also rise as a result of physical injury or damage to the eye, such as being smacked in the eye.
History of the Family- Glaucoma can run in families in some cases. You have a higher chance of developing open-angle glaucoma if your parents or grandfather had it.
Medical Background- Glaucoma is more likely to develop in those who have diabetes, high blood pressure, or have heart disease.
Use of Certain Drugs- Long-term use of corticosteroids may raise your chances of acquiring secondary glaucoma.

Diagnosis of Glaucoma

Detailed Medical Background- Your doctor will want to know about your symptoms and whether you have a personal or family history of glaucoma. They’ll also do a general health examination to see whether you have any other health issues that could be affecting your vision, such as diabetes or high blood pressure.
Tonometry is a test that measures how loud your voice is and the internal pressure of your eye is measured with this type of exam.
Test for Pachymetry- Glaucoma is more likely to occur in those with thin corneas. If your corneas are thinner than typical, a pachymetry test can notify your doctor.
Test of Perimetry- By assessing your peripheral, or side, vision and your central vision, this exam, also known as a visual field exam, can tell your doctor if glaucoma is impacting your eyesight.
Keeping an Eye on Your Optic Nerve- Your doctor may take images of your optic nerve to conduct a side-by-side comparison over time if they want to watch for progressive changes in your optic nerve.

Glaucoma Interesting Facts

The most common type of glaucoma, open-angle glaucoma, has almost no symptoms. Increased ocular pressure is rarely connected with pain. Peripheral or side vision loss is the first sign of vision loss. You may automatically adjust for this by tilting your head to the side, and you may not notice anything until your vision is severely impaired. Getting tested for glaucoma is the greatest approach to protect your vision. If you do suffer from glaucoma treatment should be from a professional and immediate.
Glaucoma is incurable, and vision loss is irreversible. It is feasible to prevent additional eyesight loss with medication and/or surgery. Because open-angle glaucoma is a chronic disease, it must be monitored for the rest of one’s life.
Glaucoma can affect anybody, from infants to the elderly. Glaucoma is more common in older people, although it can also be passed down through the generations (approximately 1 out of every 10,000 babies born in the United States). Glaucoma can strike young adults as well. African Americans, in particular, are more vulnerable when they are younger.
If untreated, glaucoma can result in blindness. Unfortunately, roughly 10% of glaucoma patients who receive effective treatment nevertheless endure vision loss.

Conclusion

Most cases are caused by a build-up of the pressure in the eye when the cerebrospinal fluid is unable to drain properly. The nerve that connects the eye to the brain is then damaged as a result of the increased pressure (optic nerve). The slow progression of optic nerve damage causes little pain, and early sight loss is limited to the periphery of the visual field, only impacting central vision later on. In most cases, both eyes are damaged, albeit one may be more severely damaged than the other. Because glaucoma visual loss cannot be recovered, effective therapy can only prevent additional vision loss.