Comparison between Goldmann Applanation Tonometry and Air Puff Tonometry for Measurement of Intraocular Pressure in Siliconized Eyes

Abstract Background Silicone oil (SO) has been a part of vitreoretinal surgery since the 1960s. The use of silicone oil in conjunction with advanced vitreous surgical techniques can successfully treat complicated retinal detachment (RD). Aim of the Work to compare the intraocular pressure (IOP) measurements following Pars Plana Vitrectomy (PPV) with injection of Silicone Oil (SO) by Goldmann applanation tonometry (GAT) and noncontact Air Puff Tonometer (APT). Patients and Methods This study included a total of 165 eyes of 165 patients. Of these 165 patients, 110 have undergone PPV and silicone oil injection, while the remaining 55 participants served as the control group. Results The participants in our study were divided into a control group, and a siliconized group which was subdivided into SO 1000 cSt (Group A) and SO 5000 cSt (Group B). The control group had an average age of 50.65±12.26 years, Group A had an average age of 53.53±12.04 years, and Group B had an average age of 55.45±12.02 years. The control group in our study consisted of 28 males (50.9%) and 27 females (49.1%), while Group A had 37 males (67.3%) and 18 females (32.7%), and Group B had 38 males (69.1%) and 17 females (30.9%). Central corneal thickness (CCT) was measured for all participants. The average CCT was 536.53±28.66µm for the control group, 531.67±29.19µm for Group A, and 527.13±28.79µm for Group B. There was no statistically significant difference in the CCT measurements between the study groups (P = 0.410). The average IOP values were obtained using both the airpuff tonometer (APT) and Goldmann applanation tonometry (GAT) methods. In the control group, the average IOP was 16.56±2.98 mmHg using APT and 15.27±2.73 mmHg using GAT. For Group A, the average IOP was 17.09±7.0 mmHg with APT and 15.61±6.43 mmHg with GAT. In Group B, the average IOP was 16.71±4.93 mmHg using APT and 15.13±4.63 mmHg using GAT. The P-value was >0.05 in all groups, indicating that the differences were not statistically significant. Conclusion the results showed a correspondence between the Goldmann applanation tonometer (GAT) and the airpuff tonometer (APT) in siliconized eyes. The differences in intraocular pressure (IOP) measurements between the two instruments were minimal and not statistically significant, with APT measurements being slightly higher than GAT measurements. The study also concluded that there is a greater chance of increased IOP following pars plana vitrectomy (PPV) and silicone oil (SO) injection with SO 1000 cSt compared to 5000 cSt, but this difference was not statistically significant. Furthermore, this IOP difference between the two methods was not correlated with age, gender, CCT, or lens status of the patients. Thus, there is good agreement between the two methods.