Eur Eye Res. Ahead of Print: EER-87587 | DOI: 10.14744/eer.2024.87587

Comparison of Intraocular Pressure Measurement Using Goldmann, Tonopen and Non-Contact Tonometers in Patients with Penetrating Keratoplasty

Menekşe Binzet¹, Tuncay Küsbeci², Hasan Mahmut Arcagök², Bora Yüksel^2
1Department of Ophthalmology, Necip Fazıl City Hospital, Kahramanmaraş,Turkey
²Department of Ophthalmology, Health Sciences University, İzmir City Hospital, İzmir, Turkey

PURPOSE: To compare intraocular pressure (IOP) values measured by Goldmann applanation tonometer (GAT) with IOP values measured by Tonopen and non-contact tonometer (NCT) in patients with penetrating keratoplasty (PKP).
METHODS: Eighty-eight eyes of 72 patients who underwent PKP surgery were included in the study. Detailed ophthalmological examination was performed. Central corneal thickness (CCT) was measured with ultrasonic pachymeter and recorded. Intraocular pressures were measured with GAT, Tonopen and NCT. Data were analyzed statistically.
RESULTS: The mean age of the patients was 56.2 ± 14.7 years, the mean duration of PKP was 62.5 ± 51.6 months. Mean CCT was 561 ± 65µm. Mean IOP values were 15.4 ± 3.0 with GAT, 12.8 ± 4.5 with Tonopen and 11.7 ± 4.6 mmHg with NCT (p <0.001). There was a difference between IOP values between GAT and Tonopen (p <0.001) and between GAT and NCT (p <0.001), while there was no difference between Tonopen and NCT IOP values (p = 0.06). There was no correlation between IOP values measured in all three methods and CCT (p> 0.05). Both Tonopen and NCT IOP values were correlated with GAT IOP values (r = 0.424, p <0.001; r = 0.374, p <0.001).
CONCLUSION: In patients with PKP, IOP values measured with GAT are higher than IOP values measured by Tonopen and NCT. GAT remains the most established method of IOP measurement in clinical practice, yet it has significant limitations in corneas that deviate significantly from normal values, as is the case in PKP. During follow-up, measurements can be taken with the same device suitable for the structure of the eye. Due to structural difference, if the IOP value measured with a device is too high or too low in patients with PKP, the IOP value should be measured with other devices and the results should be compared.

Keywords: Central corneal thickness, Goldmann applanation tonometer, non-contact tonometer, penetrating keratoplasty, Tonopen.

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