Glaucoma Diagnosis

Glaucoma can happen to anyone, and early diagnosis is the only way to prevent vision loss due to the disease. Unless there is significant damage due to glaucoma in the visual field, the patient cannot be aware of this vision loss. For this reason, it is important to carry out eye examinations and analyses at regular intervals on an annual basis. There is a risk of glaucoma (eye pressure) in approximately 2.5 out of 100 people, especially over the age of 40, and the risk of glaucoma in the community increases with age. Glaucoma can be diagnosed early with a careful eye examination. For this reason, annual eye examinations are very important.

How is glaucoma diagnosed?

1. Intraocular pressure (IOP) measurement: IOP can be measured using different methods. These are air measurement, measurement with applanation method, and measurements made with devices such as Tonopen and Icare. In general, IOP is 98% 22mmHg and below. The pressure difference between the two eyes is usually below 4mmHg. Measuring IOP alone does not indicate whether a person has glaucoma or not.
2. Corneal thickness (Pachymetry) measurement: It helps the doctor to decide whether to start the medicine in some patients. The average corneal thickness normally is around 530 microns. In patients with a high corneal thickness, the eye pressure measurement may be above the normal value as a false height, or the eye pressure may be underestimated in patients with a corneal thickness of fewer than 500 microns.
3. Gonioscopy: It’s an examination of the anterior chamber angle, which is the area where the eye water empties into the capillaries, and the reticulated structure of the "eye sink" is an important part of the glaucoma examination. Changes such as accumulations, adhesions, narrowings, raptures, and new vessel formations will guide our diagnosis and treatment.
4. Computerized visual field measurement: It is important in the diagnosis and follow-up of glaucoma. In this method losses in the visual field due to the nerve cells affected in glaucoma, which the person is unaware of, are detected. Depending on the stage of the disease, certain parts of the visual field can be subjected to a more detailed examination. In addition, by analyzing the tests performed at regular intervals, it can be determined whether there has been progressing in consecutive visual field tests over the years. In recent years, visual field test results can be combined with tests such as optical coherence tomography (OCT) mentioned below for structure-function analysis. In this way, it is possible to diagnose and follow the disease much more accurately and precisely.
5. Optic nerve head, nerve fiber layer, and macular region analysis: We can detect glaucoma-related changes, especially in the optic nerve head, retinal nerve fiber layer, and macular region, very sensitively by OCT. By using the different features of this method, we can diagnose glaucoma at a very early stage, before there is any loss in the visual field and the patient has no complaints. We can also very precisely detect whether the disease has progressed in diagnosed cases and re-plan our treatment accordingly. By using the angiography feature of the same method, we can examine the capillary density in areas that may be affected by glaucoma.
6. Anterior segment imaging methods: Detection of changes in the formations in the anterior part of the eye, which we call the anterior segment, is also of great importance in the diagnosis and follow-up of glaucoma cases. We can obtain important parameters such as anterior chamber angle, iris inclination, and anterior chamber depth with the anterior segment OCT test. We can also examine the formations that are a little further behind, which we cannot evaluate with OCT, with ultrasound biomicroscopy (UBM).
7. Other tests: In the diagnosis and follow-up of glaucoma patients, tests such as orbital B Mode ultrasonography, angiography, electrophysiological tests, microperimetry, and examination under general anesthesia (especially infant patients) can be performed when needed.

Prepared by the Dünyagöz Hospital Editorial Board.

Last update: 18.12.2022

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