What is Glaucoma?
Glaucoma is a condition which can affect sight, usually due to build up of pressure within the eye.
Glaucoma often affects both eyes, usually to varying degrees. One eye may develop glaucoma quicker than the other.
The eyeball contains a fluid called aqueous humour which is constantly produced by the eye, with any excess drained though tubes.
Glaucoma develops when the fluid cannot drain properly and pressure builds up, known as the intraocular pressure.
This can damage the optic nerve (which connects the eye to the brain) and the nerve fibres from the retina (the light-sensitive nerve tissue that lines the back of the eye).
There are several forms of glaucoma; the two most common forms are primary open-angle glaucoma (POAG) and angle-closure glaucoma (ACG). Open-angle glaucoma is often called “the sneak thief of sight” because it has no symptoms until significant vision loss has occurred.
Did you know?
- Harry’s got his mother Lily’s eyes; there’s a good chance that he’ll be affected by Glaucoma just the way his mom was. Yes, Glaucoma is inheritable. Anyone with a family history of this disease should be doubly cautious.
- Glaucoma can affect infants too wherein the child, is born with the disease. Children with congenital glaucoma generally have a hazy vision.
- Glaucoma is called as a silent killer for it takes you by total surprise – no pain, no symptoms. Glaucoma is the second most leading cause of blindness in the world.
Glaucoma is the name given to a set of different eye disorders which cause progressively increasing damage to the optic nerve, leading to progressive irreversible loss of visual field. The optic nerve connects and transmits visual signals from the eye to the brain. In most types of glaucoma, the pressure within the eye is higher than normal, and this high pressure directly damages the nerve. Not every eye with high pressures develops glaucoma, however, it is a known risk factor and people with high pressures therefore need regular eye examinations to rule out glaucoma. There is no specific level of eye pressure that definitely causes glaucoma or eliminates the risk of glaucoma. In some cases normal pressures can still lead to glaucoma. Advanced glaucoma can lead to blindness, hence its early diagnosis and treatment is imperative.
You are considered to be in a higher-than-normal risk category if you have any ofthe following:
- High IOP
- Age >40 years
- Family history of glaucoma
- History of eye injury
- History of steroid use, topically / systemically
- Are near-sighted (myopia, need minus powered spectacles)
Other risk factors, which can be detected only on examination, include:
- High eye pressure
- Thin corneas
- Differences in the optic nerves of both eyes
If you have any of these risk factors, you need to consult you eye specialist. At Eye Infirmiry we can determine your risk level and need for future check-ups.
GLAUCOMA DIAGNOSTIX @ THE EYE INFIRMARY
At The Eye Infirmary we have a dedicated Glaucoma clinic, running on all days of the week. Glaucoma is diagnosed through a comprehensive eye examination. This includes:
- Patient history – any specific symptoms, eye diseases, general health problems, family history and medication history.
- Vision testing – although affected only in advanced glaucoma, it gives an indication about the visual function of the eye.
- Eye pressure measurement (Tonometry) – high eye pressure is an important risk factor for glaucoma, and treatment is based mainly on reducing the eye pressure.
- At The Eye Infirmary we use the gold-standard Goldmann Applanation Tonometer as well as a state-of-the-art Non-Contact Tonometer for this purpose.
- Corneal thickness measurement (Pachymetry) – to detect an additional risk factor for glaucoma, namely thin corneas.
- Gonioscopy – a test to directly view the area of the eye (angle) from where the aqueous drains, and assess whether it is open or closed.
- Comprehensive slit-lamp examination – to look at the various structures of the eye
- Optic nerve head examination – which gives an idea about nerve damage due to glaucoma and comparison between the two eyes.
Other tests which are done and may require to be repeated are:
- Stereoscopic Disc Photos – these photographs of the eye nerve serve as a baseline for visible nerve damage, and are a useful comparison for future visits.
- Visual field testing (Perimetry) – to check if the field of vision has been affected by glaucoma. Usually the disease affects the peripheral vision first & later on may spread to affect the central part of the field. This test helps to confirm nerve damage by glaucoma and also is useful in monitoring whether the disease is under control. At Eye Infirmiry we use the HumphreyTM Perimeter for this purpose, preferred the world over
- Optical Coherence Tomography (OCT) – this test is useful in early or doubtful cases of glaucoma. It measures the microscopic thickness of the retinal nerve fibre layer and the ganglion cell complex (GCC), and provides a detailed 3-D image of the same. The test can confirm the presence or absence of glaucoma when other tests are uncertain. It is especially useful in detecting early glaucoma, sometimes even before Perimetry can detect the disease. Eye Infirmiry is equipped with the most advanced Heidelberg Spectra.
- The Anterior Segment OCT – This is used to look at the status of the angle of the anterior chamber (the site of aqueous fluid drainage). It can also give us the exact angle measurements, the corneal thickness, and can be used post-operatively to assess the status of the Trabeculectomy bleb.
OCT-GLAUCOMA MODULE PREMIUM EDITION
Next generation glaucoma diagnostics
The SPECTRALIS® Glaucoma Module Premium Edition combines the proprietary Anatomic Positioning System (APS) with a series of unique scan patterns to assess the optic nerve head, the retinal nerve fiber layer, and the ganglion cell layer. These scan patterns are precisely matched to the characteristics of fine anatomic structures relevant in glaucoma diagnostics.
The glaucoma module compares patients’ eyes to a reference database of normal eyes, noting even very small deviations. The precision of the SPECTRALIS AutoRescan function allows confident identification and monitoring of structural changes from visit to visit.
GLAUCOMA CARE @THE EYE INFIRMIRY
Presently, glaucoma treatment is aimed at reducing intraocular pressure whatever be the type of Glaucoma.
In an Angle closure glaucoma, one needs to start treatment with a Laser, followed by Medications / Surgery. Reduction in intra Ocular Pressure (IOP) can be achieved by medication (eye drops or tablets), laser, or surgery. It is important to remember that there is no cure for glaucoma, and that nerve damage that has already occurred cannot be reversed. In other words, vision that has been lost due to glaucoma cannot be regained; vision can only be retained.
- Medications – there are a number of medications, which can either reduce the aqueous production or increase the aqueous outflow. They can be used either singly or in combination to get to the Target IOP. After starting treatment, your glaucoma specialist will call you back to confirm its efficacy and to look for any minor side effects.
- Laser Peripheral Iridotomy (PI) – This is done with the help of a YAG Laser. This procedure helps in opening up a closed ‘angle’, the area in the eye from which the fluid drains by making a small hole in the iris (coloured part of the eye). Overcoming this block can automatically prevent eye pressure fluctuations in patients with this type of glaucoma and prevent an acute attack of angle closure from setting in.
- Micropulse Laser Trabeculoplasty (MLT) – Eye Infirmiry is one of the few centres in Bahrain which offers this advanced modality. MLT is suited for patients with primary open angle glaucoma. This laser acts on the trabecular meshwork and opens it out, thereby enhancing the aqueous outflow. It provides long-term freedom from eye drops.
- Trabeculectomy – Trabeculectomy surgery is the gold standard in glaucoma surgery, and is primarily used in patients in whom the eye pressure cannot be controlled with medication. Here a new pathway is created for theaqueous to be able to drain out, thereby relieving hight eye pressure. To get better outcomes anti-fibrotic agents like Mitomycin-C are used.
- MicroPulse – Latest techology which decreases IOP with a possible dual mechanism of targeting the ciliary processes and increasing the uveoscleral outflow. A transscleral diode laser, the Cyclo G6 laser system (Iridex) with a P3 probe, is used for this procedure.
- Valve implants – Valves such as the Ahmed valve and Addi valve can be placed in the eye to control eye pressure, especially in complicated cases
- In Congenital Glaucoma – surgical treatment is the way to go, and combined Trabeculotomy-Trabeculectomy has been proven to give the best