Fluorophotometric measurements of aqueous-humor flow in post-YAG laser iridotomy for acute angle closure

Objective@#This study compared the rates of aqueous-humor flow and trabecular outflow in eyes that had undergone YAG laser iridotomy (LI) for primary-acute-angleclosure (PAC) attack and primary-angle-closure suspect (PACS).@*Methods@#Patients who had PAC attack in one eye and narrow occludable angles (PACS) in the other eye that had undergone YAG LI were recruited. All underwent complete ophthalmologic examination including gonioscopy, ultrasonic pachymetry, A scan, and fluorophotometry to determine the rate of aqueous-humor flow. The Goldmann equation was used to compute the outflow facility using the values of aqueous flow and intraocular pressure (IOP).@*Results@#Fifty eyes of 25 patients were included, 25 of which had PAC attack and 25 were PACS. The central corneal thickness (CCT), anterior-chamber depth, and anterior-chamber volume of the 2 groups were comparable. PAC-attack eyes had significantly higher IOP (18.4 mm Hg) than the PACS (14.12 mm Hg) (p = 0.001). The mean rate of aqueous flow was 2.50 ± 0.94 µL/min and 2.89 ± 1.17 µL/min in the PAC and PACS respectively (p = 0.20). The mean aqueous-outflow facility was 0.29 ± 0.18 µL/min and 0.59 ± 0.37 µL/min respectively (p = 0.0008).@*Conclusion@#A significantly lower aqueous-outflow facility was demonstrated by fluorophotometry among eyes with PAC. Despite the anatomically open angles, they continued to have higher IOPs.

Relationship between the rabbit glucocorticoid receptor and steroid-induced glaucoma / 眼科新进展

Objective　To study the correlation between the rabbit glucocorticoid receptor(GR) and steroid-induced glaucoma(SIG).Methods　The GR binding in peripheral blood leukocytes and plasma cortisol were measured in 15 adults pigmented rabbits on the first day of experiment, 0.5mg dexamethasone was injected in the right eyes of each rabbit once every 2 days, totally 15 times for 30 days. Right eyes intraocular pressure(IOP) and aqueous outflow facility were measured every week, the relation between GR, plasma cortisol, IOP and aqueous outflow facility(C) was analyzed. Results　After the experiment the IOP increased by 0.67kPa±0.49kPa(P＜0.01),C decreased by 0.08±0.11(P＜0.01).GR may closely be related to IOP and C(r=0.56,P＜0.025; r=0.60,P＜0.01).Plasma cortisol was independent of IOP and C(r=0.27, P＞0.05;r=0.34,P＞0.05).Conclusion　The level of GR has positive correlation with the sensitivity of tissue of eye to glucocorticoid.

The Study for the Outflow Of Aqueous Humor after Injection of Dye into the Anterior Chamber

The aqueous bumor makes an important role to maintain intraocular pressure. The production and outflow of aqueous humor controls the intraocular pressure. The accurate understanding of the pathway of aqueous outflow and the rate of outflow is essential to the study of glaucoma. The purpose of this study is to investigate the pathway of aqueous outflow after injection of dye into the anterior chamber, the duration of staining and the degree of delay of aqueous outflow after the use of viscoelastics. Three dyes. Gentian Violet, Methylene Blue and Viscoelastics mixed with Gentian Violer were injected into the anterior chambers of 20 eyes of 10 rabbits. The eyes were enucleated at 1 hour, 2 hour, 3 hour, 4 hour after injection of Gentian Violer and Methylene Blue. After injiection of viscoelastics mixed with Gentian violet, the eyes were enucleated at 2 hour, 4 hour, 6 hour, 8 hour, and 9 hour. The enucleated eyes were performed for frozen section and the fragments were observed by light microscopee. Gentian violet and Merhylene Blue were stained in the pathway of the pectinate ligaments, trabecular meshwork, intrascleral plexus and the pathway of the capillary network of iris and suprachoroidal space. The disappearance of injected dye was ended between 3 hour and 4 hour. And the viscoelastics mixed with dye was removed between 8 hour and 9 hour. This means that viscoelastics make the outflow of aqueous delay.

The Effect of Endothelin-1 on IOP and Aqueous Outflow Facility in the Rabbit Eye

Endothelin(ET) is known as a family of potent hydrophobic, vasoactive peptide. We investigated the effect according to the concentrations of ET on intraocular pressure(IOP), aqueous outflow facility, pupillary diameter and light reflex and iris vessels. Twenty-four hours after injection of 2.5 microgram and 10 microgram of ET-1 into the anteriorvitreous of rabbit eyes, the IOP was reduced by 69% and 80%, respectively and did not return to the level of prefreatment until at least 14 days and 20 days, respectively. But the decrease of IOP was not due to the increased aqueous outflow. The pupillary diameter of ET-1 treated eyes was 1 to 2mm larger than the pretreatment. The time course of the pupillary effects generally ran paralled with the reduction of IOP. The iridial and conjunctival hyperemia was detectable during the pupillary dilatation. Endothelins are therefore potential participants in the local regulation of IOP, ocular blood vessel tone, and iris smooth muscle tone.