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Introduction: The study aimed to assert the relationship between central corneal thickness (CCT) and intraocular pressure (IOP) measured by: Goldmann applanation tonometry (GAT) and Dynamic contour tonometry (DCT). Materials and Methods: The study included 150 patients with a mean age of 59.39 ± 13.12 years. Patients were divided into three groups: 50 primary open-angle glaucoma (POAG) patients, 50 ocular hypertension (OHT) patients, and 50 normal tension glaucoma (NTG) patients. IOP was determined using GAT and DCT. CCT was measured by ultrasound pachymetry. Results: IOP measured with DCT was higher than IOP measured with GAT (19.80 ± 3.67 mmHg vs 17.71 ± 3.35 mmHg). A significant positive association between IOP measured with GAT and IOP measured with DCT was found in all patients (r = 0.867, p < 0.01). A significantly positive association between IOP measured with GAT and IOP measured with DCT in POAG (r = 0.855, p 0.05). Conclusion: CCT-influenced IOP was measured by both methods, GAT and DCT. DCT can not replace GAT, but it is very useful, especially in cases where errors are in the IOP GAT measurement.

Tonometry is a method for measuring intraocular pressure (IOP). Goldmann applanation tonometry (GAT) represents a golden standard for measuring IOP. The measurement is conducted by measuring the force needed to straighten out a certain area of the cornea. Errors do occur when using the GAT method: inadequate shape and arrangement of fluorescent pictures, bulbar pressure, wrong calibration, astigmatism, corneal pathology (edema, distortion, central corneal thickness), body posture, obesity, the Valsalva maneuver. Modifications of Goldmann's applanation tonometry are methods by Dreger, Perkins and Halberg. Alternative ways to measure IOP are: the digital method and the impression method using Schiotz tonometer. The dynamic contact tonometry(DCT, PASCAL) uses contact, but is a non-applanation method of measuring IOP. It is based on the matching shapes of the head of the tonometer and the cornea, enabling the head of the tonometer to take on the role of the bulbar sheath. Therefore, it directly measures the force transferred onto the bulbar sheath, which is the result of IOP. DCT is an ophthalmology device available commercially since 2004 that measures IOP directly by measuring dynamic pulsatile fluctuations in IOP using a piezoelectric sensor embedded into the tip that touches the cornea. Other tonometry methods are: a) pneumotonometry, b) Ocular Blood flow (OBF), c) non contact tonometry: Grolman's air tonometer, Air-puff tonometer, Ocular Response Analyser (ORA), d) Mackay-Marg electric tonometer, Tono-Pen, Proview Phosphene tonometer, Rebound tonometar. Goldmann applanation tonometry continues to be the golden standard in measuring IOP. It is exact, but not too precise. If more precise measurements are needed other methods of measuring IOP are available.

Glaucoma is defined as a chronical progressive optical neuropathy with morphological (excavation of the optic nerve head) and functional disturbances (defects in the field of vision). According to the WHO data 60 million people have been diagnozed with glaucoma worldwide, 4 million of whom are blind. Clinical glaucoma is classified as: primary, secondary and congenital. Intraocular pressure (IOP) is the fluid pressure inside the eye. Normal IOP is between 10 and 22 mmHg. It depends on the homeostasis between production and elimination of eye fluid. There are three mechanisms for production of eye fluid: diffusion, ultrafiltration and active secretion. Primary open angle glaucoma or simplex glaucoma develops due to slow clogging of drainage channels in the wall of the angle. Primarily, the normal ability of the eye to eliminate more than 2.2 microliters of fluid per minute is reduced. Risk factors for open angle glaucoma include: raised intraocular pressure, age of the patient, positive family history, race, central cornea thickness, pseudoexfoliation, miopia and vascular factors (local and systemic). Raised intraocular pressure is still considered to be the most important risk factor for glaucoma development.