Abstract
Purpose :
To determine how age effects outflow facility in humans.
Methods :
In order to avoid the errors of previous methods for determining the outflow facility, the Oculo Pression Tonometry (OPT) was used and carried out in the following way:
The pressure increase to determine the pressure-dependent outflow is always the same for each eye, that is the outflow system is always exposed to the same pressure. The outflow volume during the pressure load period then depends exclusively on the outflow facility.
The oculopression is performed on both eyes simultaneously with suction cups that are placed temporally on the sclera. The IOP is always increased to 40 mmHg regardless of the initial intraocular pressure.
The volume lost during oculopression is calculated from the intraocular pressure (IOP) before (Po) and the IOP after the end of oculopression (Pr0) with the Friedenwald relationship and the rigidity coefficient.
Results :
The outflow facility was determined in 162 healthy volunteers following the Helsinki Declaration criteria for biomedical research. The subjects received a complete ophthalmological examination.The IOP was measured with a calibrated Goldmann applanation tonometer.
Outflow facility proved to be strictly dependent on the subjects` age. The 162 subjects were divided into four age groups with the following results:
Years n % Ctr (Mean) SD 95% CI
≤ 30 26 16.0 0.66 0.10 0.63 - 0.70
31-45 53 32.7 0.56 0.05 0.54 - 0.57
46- 60 51 31.5 0.50 0.03 0.49 - 0.51
>60 32 19.8 0.44 0.04 0.43 - 0.45
Conclusions :
The regression equation for the age dependence of trabecular outflow facility (Ctr) is y = 0.005x + 0.77. The distribution of data of the regression line (Sry) is 0.59, the correlation coefficient r = 0.847.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.