Diagnosed with Glaucoma: An Introduction

Introduction:

Glaucoma is a chronic, progressive disease that damages the optic nerve of the eye and causes a rise in pressure called intraocular pressure. It poses a diagnostic dilemma for ophthalmologists (eye doctors) and the patients get frustrated because it is often identified at an advanced or late stage and the patients are unaware that they even have a disease. Glaucoma is the second major reason of blindness in the world.

Who Is Affected by Glaucoma?

Glaucoma can affect individuals of any age but is prevalent among the elderly. It is the primary cause of blindness in adults over 60 years of age. Glaucoma can affect both eyes but can be worse initially in one eye.

What Are the Types of Glaucoma?

The following are the types of glaucoma:

• Open-Angle Glaucoma: This is the most prevalent type of glaucoma in which there is a buildup of resistance in the eye’s drainage canals. The drainage canals seem to be open and normal in their function. With time, the fluid present in the eye can accumulate and exert pressure on the optic nerve. Glaucoma may not be noticed for a few years since most people do not experience any symptoms.

• Closed-Angle Glaucoma: This type of glaucoma has a sudden onset and is acute in nature. It is also referred to as narrow-angle or angle-closure glaucoma. Closed-angle glaucoma can happen if the angle between the iris (the colored tissue at the front of the eye comprising the pupil in the center) and cornea (the transparent portion of the eye that covers the iris and the pupil) is very narrow.

• Normal-Tension Glaucoma: Experts are not sure about the cause of normal-tension glaucoma. About 1 in 3 people have optic nerve damage despite the eye pressure being normal or slightly above normal. It is also called normal pressure or low-tension glaucoma. It is prevalent among Asian Americans or people of Asian origin.

• Congenital Glaucoma: This type of glaucoma is also called infantile or pediatric glaucoma and occurs when the drainage canals do not form properly in the womb. The symptoms of glaucoma may be noticed in the baby at birth or during childhood.

What Are the Reasons for Glaucoma?

Aqueous humor is a fluid in the eye that maintains pressure and provides nourishment to the eye. This fluid exits the eye through a mesh-like channel called the trabecular meshwork that is located in the cornea and iris. When there is excess production of fluid or if the channel gets blocked, there can be an accumulation of fluid in the eye. This fluid accumulation can increase intraocular pressure which in turn can damage the optic nerve. The reason for this blockage or obstruction is not known but is attributed to hereditary reasons.

Other rare causes of glaucoma include severe eye infection, medications such as corticosteroids, use of dilating eye drops, high blood pressure, poor blood supply to the optic nerve, blunt or chemical injury to the eye, inflammatory conditions, and blocked blood vessels in the eye. Another less common cause of glaucoma could be a result of surgery that is performed to correct another condition.

What Are the Symptoms of Various Types of Glaucoma?

The following are the symptoms:

• Open-Angle Glaucoma:

• No symptoms in the initial stages.

• Patchy blind spots may develop gradually in the side vision which is also called peripheral vision.

• There can be difficulty in seeing objects in the central vision in the late stages.

• Acute-Angle Closure Glaucoma:

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• Severe pain in the eye.

• Severe headache.

• Blurred vision.

• Nausea or vomiting.

• Halos or colored rings around lights.

• Redness in the eyes.

• Normal-Tension Glaucoma:

• No symptoms in the initial stages.

• Blurred vision can be experienced gradually.

• There can be loss of side vision in the late stages.

• Congenital Glaucoma:

• Increased blinking is observed in infants.

• A dull or cloudy eye in infants.

• Tears without crying occur in infants.

• Blurred vision.

• Headache.

• Nearsightedness can get worse.

What Are the Risk Factors Associated With Glaucoma?

The risk factors are as follows:

• More than 40 years of age.

• Are of Irish, Russian, Japanese, African American, Hispanic, Inuit, or Scandinavian origin.

• Being nearsighted or farsighted.

• Have poor vision.

• Diabetic individuals.

• Have a family history of glaucoma.

• History of injury to the eyes.

• Corneas that are thinner than normal.

• Increased eye pressure.

• Those having elevated blood pressure, heart disease, and sickle cell anemia (a condition in which red blood cells are damaged and there is a change in shape).

• Those who take steroid medications like prednisone.

• Those who take medications for seizures, bladder control, or some of the over-the-counter drugs to treat a cold.

How Is Glaucoma Diagnosed?

Glaucoma is diagnosed in the following ways:

• Detailed History: The physician will enquire about the family history of glaucoma and ask about the symptoms in detail. A query regarding the presence of other health conditions like diabetes or hypertension (high blood pressure) that can impact eye health may be put forth by the physician.

• Dilated Eye Examination: The pupils are widened to examine the optic nerve located in the back of the eyes.

• Tonometry Test: This test is used to measure the internal pressure in the eyes.

• Pachymetry Test: People with thin corneas are susceptible to developing glaucoma. Hence, the pachymetry test is used to detect if the corneas are thin or not.

• Perimetry Test: It is also called the visual field test and is used to measure central, side, or peripheral vision.

• Gonioscopy: This test is used to examine the angle where the iris and cornea meet.

• Slit-Lamp Exam: The inside of the eye is examined using a microscope called a slit lamp.

• Visual Acuity Test: This test is used to evaluate vision loss.

• Monitoring the Optic Nerve: Photographs of the optic nerve may be taken to make a comparison of the gradual changes to the optic nerve over time.

How Is Glaucoma Treated?

The following are a few treatment modalities:

• Medications: Various eye drops are available on prescription to treat glaucoma. A few of these decrease the fluid buildup and improve drainage to ease intraocular pressure. It might be required to take eye drops daily since glaucoma is a life-long condition. Few glaucoma drugs can have an impact on the heart and lungs hence, it is advisable to inform the physician about the other prevailing health conditions.

• Laser Therapy: Lasers are considered the first line of therapy instead of drops or as an accompaniment to eye drops. Laser treatment is not a complete replacement for eye drops. The results from laser treatments can differ but can last for a few years in certain cases. Some types of laser treatments may need to be repeated.

• Surgery: Surgery for glaucoma is an invasive technique and the results pertaining to eye pressure control are better than eye drops or laser technique. It can retard vision loss but cannot rectify it. Surgeries are classified into different types based on the severity and the type of glaucoma. One such traditional surgery is minimally invasive glaucoma surgery (MIGS). There are various types of this procedure like the availability of different types of stents or devices to enhance the fluid outflow from the eye. The benefits of the MIGS procedure are that it is quick, has a faster recovery period, and there are a few risks involved.

When Should Glaucoma Testing Be Done?

Early detection of glaucoma can evade vision loss and protect the eyes. Glaucoma testing should be undertaken in the following ways:

• One to three years after 35 years of age for people at high risk.

• Two to four years before age 40.

• One to three years between ages 40 and 54.

• One to two years between ages 55 to 64.

• Six months to 12 months after age 65.

Can Glaucoma Be Prevented?

The following are the ways to prevent glaucoma:

• A regular eye examination is necessary.

• Knowledge of the family history of glaucoma is important.

• The doctor’s instructions have to be carefully followed.

• Protective eyewear should be used while playing sports.

• One can engage in moderate activities such as walking or jogging at least three times a week.

Conclusion:

Glaucoma is a condition that affects vision due to increased fluid accumulation which results in the rise of intraocular pressure. One experiences no symptoms in the initial stages. The presence of other conditions like diabetes can increase the risk of glaucoma. Regular eye examinations should be undertaken to identify glaucoma in the early stages. If left untreated, glaucoma can aggravate permanent vision loss. Treatments aim at retarding vision loss but these do not offer a permanent cure.