Types of Glaucoma, Clinical Spectrum of disease

  1. I have angle closure glaucoma. How is it different from open angle glaucoma?

Types of Glaucoma
Types of Glaucoma

In angle-closure glaucoma, the fluid within the eye cannot drain through the angle because the drainage angle is narrow, or closed in parts. This may result in a sudden increase in eye pressure, the symptoms of which include a red, painful blind eye. This is an eye emergency and you must seek immediate medical help.

The chronic form the disease is like open angle glaucoma with occasional coloured halos and headaches.

Typically, you doctor will offer you a laser peripheral iridotomy, a procedure that forms an alternate drainage pathway for the fluid inside the eye. Subsequent to this, you may or may not require lifelong anti glaucoma eye drops.

  1. I have glaucoma. But my eye pressures are normal without any medication.

It can be rather confusing at first, when your doctor tells you that despite normal eye pressures, you are suffering from glaucoma. About 10-25% of people with glaucoma do not exhibit higher than normal eye pressures.

The exact cause for this is not known, but it may be attributed to an unusually fragile optic nerve which is unable to withstand even the pressures that are considered normal for population (typically <21mmHg). Some researchers also believe that this may be due to a deranged blood supply to the optic nerve.

Associations of Normal Tension or Low Tension Glaucoma include:

  • Japanese ancestry
  • Family history of normal tension glaucoma
  • History of migraines and vasospastic disorders like Raynaud’s disease
  • Sleep apnoea
  • Alzheimer’s disease.
  1. My eye pressures are high. My doctor says I do not have glaucoma, only ocular hypertension.

In case your eye pressures are higher than normal, but your doctor sees no evidence of damage to the optic nerve or the visual field, you are said to have ocular hypertension (OHT).

OHT is known to be a precursor of glaucoma, as many people with high eye pressures subsequently develop optic nerve and visual field damage.

In case your doctor thinks it appropriate, you will be asked to take eye drops or in certain cases, selective laser trabeculoplasty.

Since most glaucoma treatments including eye drops have side effects, your doctor may advise you to not get any treatment for the OHT until optic nerve or field changes develop. You age, race, family history and corneal thickness will all determine your treatment plan.

In either scenario, you must remember that regular eye checks will be required to ensure that you do not develop significant visual field loss.

  1. I am a glaucoma suspect. I have no symptoms, and all my tests, including visual fields were normal last year. Still my doctor has advised tests this year.

A glaucoma or disc suspect is someone who has optic nerves that look like they are damaged from glaucoma. The doctor looks at the cup-disc ratio and determines if that is within the population normal (usually a C:D ratio of 0.5:1, may require subsequent testing). In case the doctor observes an asymmetry between the optic nerves (C:D ratio difference more than or equal to 20%), you will be advised tests.

In case your eye pressures are higher than the population normal, or in case there is a discrepancy between the eye pressures of the two eyes, your doctor might ask you to get annual eye exams to monitor any visual field loss.

These tests are usually repeated annually for a few years until your doctor is satisfied that there is no change from baseline, and then you might be asked to come for visual field testing once every two years.

  1. My baby has been diagnosed with glaucoma. How is that even possible?

Glaucoma can affect all age groups, though it is more common in the elderly. Children may be born with a congenital defect in the drainage angle of the eye, resulting in a congenital glaucoma. These children typically have cloudy eyes, sensitivity to light, and excessive tearing. Most mothers notice that the baby burrows his head into the pillow, trying to shield himself / herself from light.

Your eye doctor may initiate eye drops, but will eventually recommend surgery for the child. A timely surgical intervention can ensure that these children have good vision later on in life also.

Your child may have a coincident cataract or other eye abnormalities which must be managed. Your doctor may prescribe glasses, eye drops and /or subsequent surgeries, as required. Amblyopia or lazy eye therapy may also be recommended.

Please remember that children with glaucoma can lead fully functional lives, with a little support.  Even in cases where there has been a partial loss of vision, tailor made treatment protocols will ensure that the child can remain independent. It is important as a parent to remain optimistic and encourage the child to be independent and participate in all age appropriate activities