Browsing by Author "Kruger, Hester"

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    A comparison of rebound and applanation tonometry in anaesthetised children with and without Primary Congenital Glaucoma: A cross-sectional comparative study
    (University of the Witwatersrand, Johannesburg, 2024) Kruger, Hester
    Intraocular pressure (IOP) measurement should be accurate in a paediatricpopulation with primary congenital glaucoma. Aim To investigate the difference between the change in IOP measurements using rebound tonometry (RBT) and handheld applanation tonometry (Perkins Applanation Tonometer / PAT) in patients with and without primary congenital glaucoma (PCG). Setting Soweto, South Africa. Methods Demographic data, including age and gender was analysed. IOP measurements were done under anaesthesia, using RBT and PAT at 0, 5 and 10 minutes after induction and prior to intubation. Corneal pachymetry and corneal diameters were measured. Results 65 children were included, 19 with PCG and 46 without PCG. The mean age (SD) was 3.2 (2.27) and 4.8 (2.42) years respectively. The overall mean difference in IOP between RBT and PAT across both PCG and non-PCG groups was found to be 4.92 mmHg (95% CI 2.80 – 7.03) p <0.001, with RBT having higher readings. This difference was greater in the PCG group, with the IOP difference of 9.05 mmHg (95% CI 2.6 – 15.5) p=0.004. Mean corneal pachymetry (SD) was 585.6 (81.48) μm in the PCG group and 518.31(39.90) μm in the non-PCG group. Univariate analysis showed that IOP was significantly related to corneal pachymetry, with a 11 mmHg increase in IOP for every 100 μm change in corneal thickness for measurements done with RBT (p<0.001), compared to 4mmHg using PAT. (p=0.008). Mean horizontal corneal diameter (SD) was 13.95(1.24) mm in the PCG group, compared to 11.09(0.32) mm in the non PCG group. Conclusions IOP measurements done with RBT in children with and without PCG were overestimated compared to PAT. This difference was more pronounced in PCG patients. In addition, IOP was significantly related to corneal thickness.