Annual regular eye checkup is the key to prevent the loss of vision caused by glaucoma. People between the age of 40 and 60, it is recommended for eye checkup at every 12 months. Individuals who are at high risk should go for a test every year after age 35. Approximately 60 to 67 million individuals have glaucoma globally so early detection and prompt treatment only can reduce the damage to the optic nerves bundles. Diagnosis is not an easy process; require a complete examination and evaluation of the optic nerves damage. Glaucoma expert’s decision is must before any decision is made because protecting the sight is most important concern.
How Do You Test For Glaucoma?
Screening for glaucoma is ordinarily performed by ophthalmologists as part of a standard eye examination. In order to diagnose glaucoma accurately, five-factor must be evaluated before confirmation is made.
- Intraocular pressure
- Color and shape of the optic nerve
- Field of vision
- Angle in the eye
- Thickness of the cornea
- Testing intraocular pressure and optic nerve are the routines done by tonometry and Ophthalmoscopy.
Tonometry Test
Ocular tonometry is the regular test for determining the pressure of intraocular. Eye pressure is unique to each person and the fluid pressure helps to analysis the individuals whether at risk of glaucoma. Ocular tonometer is standardized to measure pressure in millimeters of mercury (mmHg). The range for normal pressure in healthy individuals is 12 to 22 mmHg. If the pressure exceeds 22 mmHg, then the individuals has positive glaucoma. However, there have been cases when individuals have had pressures within 20 mmHg range but still have glaucoma. This condition is called normal tension glaucoma. Some of the different tonometry methods are
- Applanation tonometry
- Dynamic contour tonometry
- Electronic indentation tonometry
- Rebound tonometry
- Pneumatonometry
- Impression tonometry
- Non-corneal and transpalpebral tonometry
- Non-contact tonometry
- Ocular response analyzer.
Ophthalmoscopy Test
Ophthalmoscopy test, also called funduscopy used to examine the optic nerve damage because of glaucoma. Before analysis, eye drops used to dilate the pupil and later color and shape of the optic nerves bundles are examined to confirm the damage. Ophthalmoscopy is a small instrument, which allow light and helps to magnify the optic nerve. It has two types’ direct ophthalmoscopy (15 times magnification) and indirect ophthalmoscopy (2 to 5 times magnification), both has significant part in detecting glaucoma.
Perimetry
It is used for the measurement of a person’s field of vision. Sometimes it is referred as campimetry meant for eye examination which can identify the improper function in central and peripheral region vision. Tangent perimetry is one of the simple devices used manually. Many advanced automated and computerized perimetry used at present to detect the progress of glaucoma.
Gonioscopy
Gonioscopy also referred as gonioscope used to describe the iridocorneal angle. It helps to find the anatomical angle formed between the eye’s cornea and iris. This is significant in identification of the early phases of the glaucoma and many eye diseases in individuals. A small device with lens is placed on the eyes for analysis. The lens helps the experts to see whether angle formed by the iris and cornea is blocked or closed, which is a sign suggestive of angle-closure or acute glaucoma or whether he angle is open and wide which is a sign of chronic or open angle glaucoma. Koeppe direct goniolens, Goldmann indirect goniolens, and Zeiss indirect goniolens are some of the examples of goniolenses used for diagnosis.
Corneal Pachymetry
It is the simple process of measuring the thickness of the cornea and important test in the early detection of glaucoma. It is a very useful device for experts for screening patients who are suspected of developing glaucoma disease. Either by ultrasonic or optical microscopy methods, the thickness of cornea in mm is measured. At present, ultra-high echogram design of the cornea is captured and thickness is analyzed with the help of waveform.
Sometimes two or several combined methods is compulsory for analyzing the damage of nerve fiber in the diagnosis of glaucoma cases.
- American Academy of Ophthalmology: “Glaucoma: Diagnosis.” Source: https://www.aao.org/eye-health/diseases/glaucoma-diagnosis Comprehensive information about the diagnosis of glaucoma, including key tests such as tonometry, ophthalmoscopy, perimetry, gonioscopy, and corneal pachymetry from the American Academy of Ophthalmology.
- National Eye Institute: “Facts About Glaucoma.” Source: https://nei.nih.gov/health/glaucoma/glaucoma_facts Key facts about glaucoma, including the importance of early detection and the different diagnostic tests used to detect the disease, from the National Eye Institute.
- BrightFocus Foundation: “How Is Glaucoma Diagnosed?” Source: https://www.brightfocus.org/glaucoma/article/how-glaucoma-diagnosed Detailed overview of the diagnostic process for glaucoma, including the importance of regular eye exams and the various tests used to detect the disease, from the BrightFocus Foundation.
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