Abstract
Purpose :
Examine errors from a standrard Goldmann applanation tonometer and a shaped correction surface Goldmann prism relative to intracameral intraocular pressure (IOP) in live human eyes.
Methods :
Intracameral IOP was measured via pressure transducer on fifty-eight (58) eyes undergoing cataract surgery and the IOP was set manometrically on each patient sequentially to 10, 20, and 40mmHg. The IOP was measured using a Perkins tonometer on the eyes at each set intracameral pressure both with a standard flat surfaced Goldmann prism and a modified shaped surface Goldmann prism. Differences between the two prism measurements were correlated to central corneal thickness (CCT) and corneal resistance factor (CRF).
Results :
The Goldmann-type tonometer error measured on live human eyes was 5.2 +/-1.6 mmHg lower than intracameral IOP (p = 0.0009). Insignificant bias was noted between the Goldmann and shaped surface prisms (p=0.31). A multivariate regression analysis with linear mixed-effects revealed a statistically significant decrease in sensitivity to CCT (p = 0.021) and nearly significant decrease in sensitivity to CRF (p = 0.055) using a shaped surface Goldmann prism compared to a standard Goldmann prism.
Conclusions :
Goldmann IOP measures significantly lower than true intracameral IOP by approximately 5 mmHg. Both CCT and CRF have a significant sloped correlation to Goldmann IOP measurement error when compared to true intracameral IOP. The results demonstrated a statistically significant decreased shaped Goldmann prism sensitivity to CCT IOP error and nearly significant decreased sensitivity to CRF when compared to the standard Goldmann prism.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.