Glaucoma

The term glaucoma describes a group of different eye conditions which untreated will damage the optic nerve and result in blindness. The optic nerve conducts light impulses from the retina to the visual cortex of the brain, where they are transformed into optical images.

Primary Glaucoma

High-pressure Glaucomas-

Wide-angle or open angle Glaucoma:

The exact cause for this type of glaucoma is not known, however it is believed that the shape of the iridocorneal angle, through which the intraocular fluid (aqueous humour) flows. The intraocular fluid nourishes the lens and cornea. It is secreted from the posterior chamber of the eye (behind the iris), surrounding and moistening the lens. It travels through the pupil into the anterior (front) chamber of the eye, which is bounded by the iris and cornea. Most of the intraocular fluid flows through a vascular type system, the sponge-like trabecular tissue at the margins of the cornea, and the flow rate is influence by the iridocorneal angle. The pressure within the eye rises with the influx of intraocular fluid, and drops as the fluid is drained. A glaucoma that develops when the iridocorneal angle is too open is called wide-angle or open-angle glaucoma. This is the most common form of glaucoma. The condition progresses slowly, and in more than 70 percent of those affected the intraocular pressure exceeds 21mm Hg.

Narrow-angle or angle-closure Glaucoma:

As the name suggest this glaucoma occurs when the iridocorneal angle narrows or closes, causing a spike in intraocular pressure. This type of glaucoma can develop quickly and should be treated as an emergency. It can also cause repeated and milder forms of discomfort with the potential to become acute at any time. Other forms of narrow-angle glaucoma tend to be of a chronic nature. Having a short eye increases the likelihood of developing glaucoma.

Congenital Glaucoma:

Congenital glaucoma occurs in infants and is rare. Patients present with a malformed iridocorneal angle. The glaucoma usually advances quite quickly and consequently can be dangerous. The glaucoma should be readily addressed with an operation that creates a drain for the intraocular fluid.

Normal- or Low-Tension Glaucoma:

Primary Vascular Dysfunction (PVD)

Primary Vascular Dysfunction (PVD) is a glaucoma, which is not associated with an average rise in intraocular pressure. Indentation of the optic nerve papilla maybe associated with irregular blood circulation in the inner layers of the retina. Sharp fluctuations in blood pressure can cause a change in the structure of the optic nerve, which leads to a loss of function. Women develop PVD more often than men. Often the patient may be more sensitive to various internal and external stimuli, which affect the cardiovascular system.

Because spikes in blood pressure causes spikes in intraocular pressure by not allowing the intraocular fluid to drain and a consequential interruption to blood supply to the optic, PVD is ultimately a problem of increased intraocular pressure.

Secondary Glaucoma

Secondary glaucomas are the result of diseases, injuries or drug interactions. Cortisone based drugs or eye drops should never be used in excess.

Treatment

The ultimate goal of glaucoma is to reduce intraocular pressure. Based on a patient’s symptoms and examination data, the doctors with the patient decide on what type of intervention is best to achieve this goal. Possible interventions are:

1.Eye drops – typically prostaglandins,carboanhydrase inhibitors, beta-blockers or pilocarpine.
2.Laser treatment (532 or 810 µm ) – this treatment may have to be repeated
3.Classic glaucoma surgery (80% success rate)
4.IStent implant – implants have a higher success rate than surgery and have far fewer side effects.