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Glaucoma: the “silent thief of sight”

Get tested regularly to detect the second leading cause of blindness in the world

Glaucoma is the second leading cause of blindness in the world and in South Africa, yet it often goes undetected and untreated.

According to Dr Clive Novis, an ophthalmic surgeon at Netcare Optiklin Eye Hospital in Benoni, if not diagnosed and treated timeously, glaucoma can progress to the loss of central vision and blindness.

“Glaucoma causes gradual vision loss and is known as the ‘silent thief of sight’ because it is often only when the disease is at an advanced stage that vision loss occurs, and by then there could be permanent damage. For this reason, regular testing for glaucoma is important,” notes Dr Novis.

“Glaucoma is an eye disease that damages your optic nerve. In the early stages people do not realise that they have glaucoma because the disease may not present with specific symptoms,” he cautions.

The condition is usually seen in patients over the age of 40 and Dr Novis says the general rule is: the older the patient, the higher the incidence of glaucoma.

“Glaucoma is common in South Africa and is one of the leading causes of blindness, particularly among people of African descent. The condition is characterised by a specific pattern of progressive damage to the optic nerve, which generally begins with a subtle loss of the peripheral vision.”

“The eye has internal pressure created by the production of aqueous humour, a clear fluid that circulates through the eye and exits through the anterior chamber angle. The fluid drains into the blood stream. However, with glaucoma the aqueous humour outflow is obstructed causing an increased eye pressure that eventually damages the optic nerve. When the eye pressure rises quickly, those impacted by the condition may experience symptoms such as blurred vision, nausea and severe headaches or eye pain,” explains Dr Novis.

Testing for glaucoma

The first line of tests for glaucoma take place during a visit to the optometrist when a machine is used to send a puff of air into the eye to determine the intraocular, or eye, pressure.

Should the optometrist find an irregularity, a referral will be made to an ophthalmologist, a medical doctor who has furthered their studies to specialise in eye and vision care.

During the consultation with the ophthalmologist, tests for optic nerve damage, cornea thickness and loss of peripheral vision, as well as other indicators will be performed.

How often should your eyes be tested?

  • Every two to four years if you are younger than 40.
  • Every one to three years from 40 to 54.
  • Every one to two years from 55 to 64.
  • Every six to 12 months after the age of 65.

Who could potentially be at risk?

“People need to take the necessary steps to protect their vision, even if you have normal eyesight. Risk factors to look out for include a family history of glaucoma or eye disease, diabetes, migraine or significant eye trauma,” says Dr Novis.

He adds that persons with the following risk factors should go for glaucoma tests annually after the age of 35:

  • A family history of the condition.
  • High internal eye pressure.
  • Near sightedness.
  • Diagnosed with medical conditions such as diabetes, heart disease, high blood pressure and sickle cell anemia.
  • Earlier eye injuries or certain types of eye surgery.
  • Early oestrogen deficiency.
  • Persons using corticosteroid medications, especially eyedrops, for a prolonged period of time.

Glaucoma treatment

“Glaucoma is a disease that is not preventable and anyone can potentially develop it. There are occasions where young adults or children develop the condition and there have even been cases where babies are born with it,” says Dr Novis.

However, the good news is that the majority of glaucoma cases can be successfully managed and controlled with eye drops or laser treatment. Surgery is generally the last resort in patients with severe glaucoma. According to Dr Novis treatment depends on the type of glaucoma present but generally aims to decrease intraocular pressure and prevent damage to the optic nerve.

  • Eye drops are the first line of treatment. Often eye drops are combined with medication to reduce the intraocular pressure. Medicine works by either reducing the rate at which fluid is produced or it increases the outflow of fluid from the eye.
  • Laser treatment is used to open the drainage angle and to reduce intraocular pressure.
  • Surgery is used to create a new passage for fluid drainage and is often reserved for cases that cannot be treated with medicine.