A modified in vitro method for aqueous humor outflow studies in enucleated porcine eyes.

The aim of this study was to develop and test a short-term in vitro method for aqueous humour outflow studies using enucleated porcine eyes. The method used was a modification of two methods that have previously been used: whole eyes and anterior segment cultures. The advantage of the model used in this study was that the anterior part of the eye, including the anterior and posterior chambers, remained intact as in whole enucleated eyes, but neither iridotomia nor trephination through the cornea was needed. The deepening of the anterior chamber during perfusion was avoided by regulating the "vitreal" pressure. Test compounds were administered topically or intracamerally to an anatomically normal anterior chamber. Fresh porcine eyes (n = 48) were sectioned at the equator, and the vitreous mass was carefully removed. This anterior bisection was bound around a specific plastic chamber, thus creating a closed eye. The anterior chamber was perfused at a pressure of 15 mmHg. The mean outflow rate in the nonmedicated eye group was 3.7 +/- 0.20 microL/min (mean +/- standard error of the mean), and it increased by 18% during 9 h owing to a wash-out effect. Compounds known to enhance the aqueous outflow were used for testing the validity of the preparation.