Everyone over 40 years of age should get an eye examination to rule out Glaucoma though it can affect anybody including children and even infants. People are more at risk, those who fall in one or more of the following groups:
- Are 40 years old and above
- Have high Intraocular Pressure (IOP)
- Suffer from certain medical conditions such as Diabetes, High Blood Pressure, Cardiac diseases, Migraine and Sickle Cell Anemia
- Have a family history of Glaucoma
- Suffer from a high degree of nearsightedness or farsightedness
- Have been on steroid medications for long, particularly eyedrops
- Have suffered an eye injury or have had a complex eye surgery
Glaucoma is a condition of the eye in which the optic nerve gets affected. Glaucoma is called a “Sneak Thief of Sight” since the most common form of Glaucoma (Open Angle Glaucoma) does not present many symptoms in the early stages making it hard to detect early but if not detected Glaucoma may eventually lead to blindness. Vision loss due to Glaucoma cannot be reversed so early detection is crucial.
The process of Glaucoma detection starts with a routine eye examination which includes:
- Visual Acuity Test: Vision is tested with eye charts
- Non-Contact Tonometry: The intraocular pressure is checked with a Non-Contact Tonometer
- Slit lamp examination: Eyes are examined under magnification. This helps in optic nerve evaluation. If required, eyes are dilated to get a detailed view of the retina
Based on the findings from the routine examination, if the doctor feels that you may be a glaucoma suspect, next set of tests are conducted
- Applanation Tonometry: This is the gold standard for measuring intraocular pressure.
- Pachymetry/Central Corneal Thickness Test: In this, the Corneal thickness is measured. Corneal thickness is important because it can mask an accurate reading of Intraocular Pressure- actual IOP may be underestimated in patients with thinner CCT, and overestimated in patients with thicker CCT. IOP reading is corrected based on the findings from this test.
- Gonioscopy: This enables the doctor to check if the drainage of the aqueous humour (intraocular fluid) is hampered by angle structures.
- Perimetry / Visual Fields Test: This test provides a measure of the peripheral vision which is typically the first casualty of Glaucoma.
In addition to the above, certain tests may be required to confirm the diagnosis of Glaucoma and establish a baseline for future follow-ups, these may include one or more of the following:
1. Optic Disc Photograph: This helps in picking up structural changes and determining change over a period.
2. OCT (Retinal Nerve Fibre Layer Analysis) OR Heidelberg Retina Tomograph (HRT): These pick up early structural changes in the optic nerve via fast and reproducible scans. These are helpful in picking up Glaucoma early and are also used to monitor progression.
As stated earlier, vision loss due to Glaucoma cannot be reversed. Glaucoma treatment is aimed at slowing down or stopping the progression of the disease and this is achieved by lowering the Intraocular Pressure.
In the early stages, most Glaucoma responds well to eye drops- some decrease the fluid production, others increase the filtration to lower the intraocular pressure. Sometimes oral medicines may also be prescribed.
In some cases, Laser treatments (Laser Peripheral Iridectomy and Laser Trabeculoplasty) are required. For cases that do not respond to medical or laser therapy, Trabeculectomy surgery is an option which creates a new opening for the fluid to leave the eye. For complex/complicated cases of Glaucoma, Shunts/Valves are the treatment options.
Some of the recent surgical advances are in Minimally Invasive Glaucoma Surgery(MIGS) using implantable devices that can be combined with cataract surgery to control IOP. The most used is the ‘i-stent’ inject which is being used in clinical trials, the results so far seem to be promising.