Related Experiment Video
Updated: Feb 2, 2026

Laser-Induced Chronic Ocular Hypertension Model on SD Rats
Published on: December 4, 2007
Time Course Changes of the Mechanical Properties of the Iris Pigment Epithelium in a Rat Chronic Ocular Hypertension
Tan Li1,2, Lin Li1,2, Zhicheng Liu1,2
1School of Biomedical Engineering, Capital Medical University, Beijing 100069, China.
Background:
The flow field of aqueous humor correlates to the stiffness of iris pigment epithelium (IPE) which acts as a wall of posterior chamber. We focus on the variations of IPE stiffness in a rat ocular hypertension (OHT) model, so as to prepare for exploring the mechanism of duration of OHT.
Methods:
Episcleral venous cauterization (EVC) was applied on one eye of male adult Sprague-Dawley rats to induce chronic high intraocular pressure. According to the duration of OHT (0, 1, 2, 4, and 8 weeks), rats were randomly divided into Gw0, Gw1, Gw2, Gw4, and Gw8. Atomic force microscope (AFM) analysis was applied to test IPE stiffness in three regions: iris root, mid-periphery, and pupillary-margin in each group. Histological changes of IPE were also examined in Gw4 and Gw8.
Results:
There was an overall growing tendency of IPE stiffness in EVC eye. IPE in EVC eye was significantly stiffer than fellow eye in Gw2, Gw4, and Gw8 (in iris root, mid-periphery, and pupillary-margin, p<0.05). IPE in EVC eye in pupillary-margin was significantly stiffer than iris root in Gw4 and Gw8 (p<0.05). In EVC eye, IPE becomes thinner and IPE cell density decreases.
Conclusion:
IPE stiffness increases gradually with the duration of chronic high intraocular pressure.
Related Concept Videos
The Quantum-Mechanical Model of an Atom
Pigmentation
Melanin occurs in two primary forms: eumelanin that provides black and brown pigment and pheomelanin that provides red color. Dark-skinned individuals produce more melanin than those with pale...
Hypertension I: Introduction
Hypertension II: Pathophysiology
Hypertension V: Nursing Management
Physical and Chemical Properties of Matter

