Glaucoma: A leading cause of irreversible blindness

Glaucoma: A leading cause of irreversible blindness
Glaucoma: A leading cause of irreversible blindness

Feb 24, 2021

No one can dispute the value that our eyes hold in our lives. One of the most vital organs, a pair of good healthy eyes can not only help us safely and ably navigate the challenges in our day-to-day life but ensures a lifetime of attainment and self-realization. Conversely, a not-so-healthy pair of eyes can become such a debilitating handicap in our daily routine. While some minor as well as major eye diseases are fairly common and treatable, there are some which continue to pose a challenge to the ophthalmic community. Glaucoma is one of those eye conditions. If timely detection and treatment is not carried out, it can lead to an individual even losing his eyesight. In fact, glaucoma is one of the leading causes of irreversible blindness.

What is Glaucoma?

Glaucoma is a term used to depict a group of diseases which entail a progressive or irreversible damage to the optic nerve of the eye, which if untreated may lead to loss of sight. It is a result of the increased pressure inside the eye which usually happens because of the build-up of a fluid known as aqueous humor in the eye. As this fluid gets obstructed or blocked, the resultant increase in intraocular pressure can damage the optic nerve which in time can weaken the eyesight and eventually lead to complete loss of vision.

Mass screening doesn’t help, opportunistic screening important

Unlike Cataract, which can be detected during mass screening of a given population, Glaucoma requires a patient to specifically visit an eye doctor. This visit could be for any eye condition when an opportunistic screening can reveal whether an individual has the dreaded eye condition or not. A comprehensive eye examination with a set of tests such as dilated eye exam (to widen pupils and view optic nerve), slit lamp exam (to view inside of eye), visual acuity test (to check for vision loss), tonometry (to evaluate eye pressure), gonioscopy (to check for eye drainage), pachymetry (to measure corneal thickness), optical coherence tomography (changes in optic nerve), optic nerve head examination (to examine loss of ganglion cells and their fibres), and visual field examination(to check for any peripheral vision loss) would need to be conducted in order to establish whether an individual has glaucoma or not.

Types of Glaucoma

Generally, there are three major types of glaucoma: primary open angle glaucoma (POAG), primary angle closure glaucoma (PACG) and Secondary glaucoma. POAG is the most common type and occurs when the drainage system gets choked and progresses imperceptibly over a long time. Then PACG, a more serious type, is the result of the iris being too close to the drainage canals in the cornea. In this, the eye pressure can rise suddenly due to complete blockage of the drainage angle and unless medically intervened immediately, the individual can lose his eyesight. In a variant called Normal Tension Glaucoma, the optic nerve is damaged without the eye pressure going beyond the average range and is caused by the abnormalities in the blood flow to the optic nerve, and structural weakness of the optic nerve tissue. NTG is not very common. Secondary glaucoma is caused by other diseases which may increase eye pressure leading to optic nerve damage. These include Pigmentary glaucoma, Pseudoexfoliativeglaucoma, traumatic glaucoma, neovascular glaucoma, Irido-Corneal Endothelial Syndrome and Congenital/Childhood glaucoma.

Signs and Symptoms of Glaucoma

Each type of glaucoma has its own signs and symptoms. For instance, POAG has no perceivable or visible symptoms in the early stages and in due course of time as the disease progresses, blind spots develop in the peripheral vision. Similarly, PACG exhibits no apparent symptoms as such and can lead to a sudden attack. Signs of an acute attack would include intense pain in the eye or forehead, foggy vision, redness in the eye, halos around eyes, nausea and vomiting. Again in NTG, blind spots emerge in the field of vision which is a symptom. The symptoms in Secondary glaucoma would depend on the additional disease which is responsible for glaucoma. For Childhood or Congenital glaucoma, a baby would show sensitivity to light and clouding of Cornea. Children are also likely to frequently rub their eyes.

Who are at risk?

Although it can afflict anyone, those with a family history, advanced age or with co-morbidities such as high blood pressure, heart disease or diabetes are more likely to be at risk of getting glaucoma. In addition, those who have been on corticosteroid medications for long, or have undergone certain eye surgeries are also more at risk. Importantly, those with normal eye pressure can also get glaucoma.

Treatment

Again, the line of treatment would depend on the symptoms, stage and type of glaucoma. Typically, there are three major forms of treatment: medication/eye drops, laser treatment and surgery. And often a combination of treatments is also followed. For instance, POAG is most often treated with a combination of eye drops and surgery. But PACG is treated with a laser procedure called iridotomy in which the doctor creates a small opening in your iris using a laser allowing fluid to flow through it, relieving eye pressure. Another laser procedure is called Trabeculoplasty which is used for POAG patients. However in some cases, operating room surgery is opted for. Trabeculectomy is an important surgery in which an opening in the white of the eye (sclera) is created whilea part of the trabecular meshwork is removed by the doctor. You must remember that surgery may require follow-up sessions and a repeat surgery may also not be impossible.For Infants and congenital glaucoma, surgery is the main treatment.

Therefore, glaucoma is aptly called the ‘silent thief of sight’. With 12 million people affected and nearly 1.2 million people being blind from the disease in India, mass-level awareness campaigns must be mounted throughout the country. Also, individuals of all age groups must subject themselves to a comprehensive eye examination periodically. Parents should be alert to their baby’s eye conditions.Because glaucoma simply doesn’t give you a second chance.

https://timesofindia.indiatimes.com/blogs/voices/glaucoma-a-leading-cause-of-irreversible-blindness/

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