A complete eye examination – not only the usual reading of the chart – is mandatory, especially after the age of 40. Those at risk of developing glaucoma include:
- Those above 35 years (the risk increases with age);
- People with a family history of glaucoma;
- Those who use steroid drops, tablets or ointments;
- People with diabetes mellitus, hypertension or who have had eye injuries;
- Those who wear ‘minus’ glasses for short-sightedness;
- Anyone with complaints of pain, redness, and watering in the eyes; and
- People who see colored rings around lights.
- Actually, everyone should have a comprehensive eye examination periodically as it can help detect other preventable, controllable, or treatable diseases such as retinal detachment, diabetic eye disease, and cataract.
How is Glaucoma Diagnosed?
Since the treatment methods for open angle and angle closure glaucoma are different, it is important to identify the mechanism involved. The diagnosis (or exclusion) of glaucoma requires a detailed and comprehensive eye examination. Your doctor will do the following examinations:
- Slit lamp (microscope) examination: This special microscope is the ophthalmologist’s stethoscope and all patients, not just those suspected of having glaucoma, must undergo a slit lamp examination.
- The pressure inside the eye is measured.
- An examination of the angle of the eye is done with the help of a gonioscopy. This is a contact lens placed on the eye to examine the angle of the eye. Its use is mandatory in determining the type of glaucoma – open angle or angle closure.
- The above two steps require the use of drops to eliminate sensation in the eye. The drops may burn a little bit.
- An optic disc examination on a dilated eye is also required. The doctor will usually administer eye drops to dilate the pupil, facilitating an examination of the optic disc and the back of the eye, the retina. For obtaining a stereoscopic view on the microscope, a hand-held lens or a contact lens is the best method. A computerized scan of the optic disc may also be done.
- An automated field or perimeter test. Damage to the optic nerve limits the field of vision, but regular vision, i.e. the ability to read an ophthalmologist’s eye chart, is affected at a much later stage. In its early stages glaucoma can only be detected or monitored by using an automated perimeter test. A normal patient will have a ‘full field vision’, while a person with glaucoma has black, non-seeing areas in the field of vision.
- Many people have difficulty doing the perimeter test at first, and may be better at it the second or the third time. Baseline tests are necessary for future comparison and periodic examinations are essential to check the progression of the disease.
- Optical Coherence Tomography. Commonly Called as O-CT Scan of EYE, helps detect early changes in Retinal Nerve fibers and Optic Disc. OCT helps in assessment for glaucoma by optic nerve head (ONH) imaging. This allowed for measurement of the optic disc and surrounding retina, including peripapillary retinal nerve fiber layer (RNFL) thickness and optic disc rim and cup sizes.