What Is Glaucoma?
Glaucoma is a chronic progressive degenerative disease of the optic nerve. In a broad sense, in glaucoma, the optic nerve undergoes a process of slow death due to its nerve fibers getting squeezed by the eye's pressure. This nerve degeneration often goes unnoticed by patients as it is a painless and asymptomatic process.
Why Is It Important to Screen Asymptomatic People for Glaucoma?
The global burden of the disease is estimated to be 1 to 2 % of the world's population. It is in vogue to screen everyone above 40 years of age for glaucoma in many countries. The screening process is more important for certain high-risk groups, including people from certain races and women, as they carry a higher risk of the development of glaucoma.
The crux of the matter, as pointed out, is not only the absolute asymptomatic nature of glaucoma but also the fact that the nerve damage and hence the visual field loss is irreversible. This translates into visual impairment, leading to an economic setback for the individual, their family, and society. This makes the burden of the disease quite significant in terms of years of productive life lost, a loss that could have easily been prevented or occasionally avoided altogether.
Hence, screening for this disease in the average population is essential.
What Are the Risk Factors for Glaucoma?
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Age above 40 years.
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A family history of glaucoma.
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Certain races or ancestry.
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High cholesterol.
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Hypermetropia.
What Are the Types of Glaucoma?
There are two main types of glaucoma:
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Open-Angle Glaucoma:
In open-angle glaucoma, there are no symptoms, and the disease follows the classical course of nerve damage over a long protracted period.
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Acute Angle-Closure Glaucoma:
In angle closure, however, the picture is different. The patient develops symptoms of pain, redness, and blurred vision with the feeling of seeing haloes around light. The nerve damage process is accelerated, especially in acute attacks where the patient may lose sight in a matter of hours.
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Pigmentary Glaucoma:
This type of glaucoma occurs due to the build-up of pigmentary granules in the drainage tract, thereby stopping fluid drainage. As a result, there is a rise in intermittent pressure resulting in glaucoma. Jogging can also increase the chances of pigmentary granule deposition on the trabecular meshwork.
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Glaucoma in Children:
Any underlying medical condition or blockage in the drainage tracts can bring about an optic nerve damage leading to glaucoma in children. It can be present either congenitally or can develop over the years.
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Normal-Tension Glaucoma:
There is damage to the optic nerve in normal-tension glaucoma even when the ocular pressure is normal. The exact cause is not known in these cases. An overly sensitive optic nerve or atherosclerosis in the blood vessels supplying the optic nerve have been the attributed causes.
What Are the Symptoms of Glaucoma?
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Open-angle Glaucoma - Most open-angle glaucomas are asymptomatic and would only be picked up on screening. Symptoms that can present here can be
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Frequent changes in the glass prescription.
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Headaches that aggravate in dark environments.
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Patchy blind spots can be seen. It can be either in the central vision or peripheral vision.
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In severe cases, there can be the formation of tunnel vision.
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Acute Angle-Closure Glaucoma - Angle-closure glaucoma can present as:
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Red, watery, and painful eyes.
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Patients can have blurred vision with the symptom of seeing colored haloes around lights.
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Nausea and vomiting.
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Severe headaches.
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When Should One Get Tested?
One needs to be tested for glaucomatous disease if they have any glaucoma symptoms or any of the above-mentioned risk factors of glaucoma. In general, it is recommended that if above 40 years of age, one should undergo glaucoma testing.
What Tests Are Available for Diagnosis of Glaucoma?
The significant tests whose outcomes determine the progression of glaucoma and the treatment decisions are:
2. Optic nerve head morphology.
3. Visual field analysis.
The adjunctive tests having a corroboratory impact are:
1. Optical coherence tomography (OCT).
2. GDX/GDXVCC.
3. Corneal thickness/pachymetry.
4. HRT (Heidelberg retinal tomography).
What Are the Treatment Options Available?
Glaucoma can be treated by various options, including eye drops, lasers, and surgery. The treatment decision depends on the severity of the disease and a few patient factors.
Glaucoma is thus a progressive disease, and a quick visit to an ophthalmologist in case of symptoms or patients having risk factors can prevent irreversible nerve damage.
The following are the available treatment modalities:
1. Medical Treatment:
a. Eye Drops - These help lower eye pressure by promoting the outflow of eye fluid (aqueous humor), reducing its production, and decreasing the activity of the rho kinase enzyme responsible for increasing the eye fluid. Prescription eye drops containing any of the below medications are used in the treatment of glaucoma:
i. Prostaglandins like Latanoprost, Latanoprostene bunod, Tafluprost, Travoprost, and Bimatoprost.
ii. Alpha-adrenergic agonists like Brimonidine and Apraclonidine.
iii. Rho-kinase inhibitors like Netarsudil.
iv. Beta-blockers like Betaxolol and Timolol.
v. Cholinergic drugs like Pilocarpine.
vi. Carbonic anhydrase inhibitors like Brinzolamide and Dorzolamide.
b. Oral Tablets - In some cases, oral medications like carbonic anhydrase inhibitors can be prescribed to reduce eye pressure.
2. Surgical and Other Treatment Methods:
a. Drainage Tubes - In individuals where there is eye pressure can be reduced by removing the excess fluid by placing a drainage tube.
b. Trabeculectomy - In the whites (sclera) of the eye, an opening is created, and the trabecular meshwork is removed by the trabeculectomy procedure. Drainage of fluid helps reduce eye pressure.
c. Laser Therapy - A laser therapy called laser trabeculoplasty is done in individuals with open-angle glaucoma. The clog in the drainage tracts is removed with the help of a laser. An essential drawback of this procedure is that it takes around a few weeks to be effective.
d. Minimally Invasive Glaucoma Surgery- It is the most recommended procedure owing to the fewer associated risks and postoperative care needed for this procedure. In the majority of cases, it is carried out together with cataract surgery.
How Can We Prevent Glaucoma?
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Regular Eye Check-Ups:
Dilated eye examinations must be done periodically to help detect glaucoma at its early stages. The American academy of ophthalmology recommends the following in terms of regular eye check-ups:
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Individuals below the age of 40 years - every five to ten years.
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Individuals between the ages of 41 to 54 - every two to four years.
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Individuals between the ages of 55 to 64 - every one to three years.
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Individuals above the age of 65 years - every one to two years.
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Avoid Strenuous Exercises:
Doing exercises that are mild and moderate can help prevent glaucoma.
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History of Glaucoma:
In patients with a family history of glaucoma, screening should be done much more frequently for early detection of glaucoma.
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Use Prescription Eye Drops:
Regular use of prescription eye drops, even in the absence of symptoms, reduces the risk of glaucoma by decreasing the ocular pressure.
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Protect the Eyes:
Injury can aggravate the risk of developing glaucoma. Therefore, while working with high-speed racket sports and power tools, it is vital to wear eye-protective devices.
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Reduce Caffeine Intake:
Caffeine intake increases the risk of raising eye pressure.
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Use Pillow:
Keeping the head elevated at about 20 degrees while sleeping with the help of a wedge pillow reduces intraocular pressure.
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Moderate Fluid Consumption:
Increased liquid intake rapidly can increase intraocular pressure; therefore, it is advisable to drink moderate amounts of fluids periodically.
Conclusion
Glaucoma is characterized by optic nerve damage due to increased intraocular pressure. Taking proper preventive measures reduces the risk of developing glaucoma. Also, when you are at an increased risk of developing glaucoma, getting adequate screening helps in early diagnosis and prompt treatment.