Ocular Tonometry
The measurement of intraocular pressure is called tonometry. It is necessary for the diagnosis and follow-up of glaucoma cases and is applied with three main methods.
Digital Tonometry: In order to obtain rough information about the hardness of the globe, the doctor measures the fluctuation by pressing very lightly with the index fingers of both hands on the same eyeball (bulbus) while looking down with the eyes closed. Enough pressure is created to slightly collapse the globe. This is a method that requires experience.
Indentation Tonometry / Schiötz Tonometer (Slump Method): It is based on the principle that a certain weight will collapse the soft eye more than the hard eye. The Schiötz tonometer is an instrument that measures according to these principles. It is applied in contact with the cornea. The equivalent of the value read on the instrument is expressed by converting it to the intraocular pressure value in mm of mercury from a special table, taking into account the weight used. It is available in most clinics because it is an inexpensive device and not difficult to use. However, if it is not used appropriately, it may cause false results. It does not give accurate results in patients with high myopia.
Applanation Tonometry / Goldmann Tonometer : (Straightening Method): It is the most frequently used tonometer that can obtain the most realistic value. When the flattening surface of this instrument, which is mounted on bio-microscopes, is brought into contact with the eye with topical anesthesia and a drug, and looked with cobalt blue, the intraocular pressure is read in mm of mercury by turning the lever on the side of the instrument until the inner parts of the yellow half rings on both halves of the straight horizontal line come into contact with each other.
Non-contact Air Blown Tonometer: The device does not come into contact with the eyes. Therefore, there is no risk of transmission of infection among patients. The center of the cornea is flattened by the air sprayed from the tip of the instrument, and the reflected air is sensed by the instrument again, and the intraocular pressure value in mm of mercury is obtained.
* The content of the page is for informational purposes only, please consult your doctor for diagnosis and treatment.
