Silicone Oil-Induced Glaucoma Model for Neuroprotection Testing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current glaucoma models are inadequate for accurately mimicking human glaucoma, particularly in terms of inducing rapid and reversible ocular hypertension, which hinders the development of neuroprotectants and complicates the assessment of neurodegeneration and visual function changes.
Innovation Solution
A silicone oil-induced ocular hypertension model in mice and non-human primates, where silicone oil is injected into the anterior chamber to block the pupil, causing acute glaucoma-like conditions without structural damage, allowing for controlled and reversible elevation of intraocular pressure, facilitating the study of neurodegeneration and neuroprotective therapies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If microbeads are injected to occlude aqueous humor circulation, then ocular hypertension and glaucomatous neurodegeneration are produced, but retaining microbeads at the angle and controlling aqueous outflow blockade is difficult
Solution Approach 1:
The patent removes the problematic microbeads from the anterior chamber angle and replaces them with silicone oil injected into the vitreous cavity. This extraction eliminates the difficulty of retaining microbeads while maintaining the occlusion effect through the lighter silicone oil that naturally floats to block the pupil and prevent aqueous flow into the anterior chamber.
Solution Approach 2:
The patent introduces silicone oil as an intermediary substance that mediates between the posterior and anterior chambers. The silicone oil acts as a physical barrier that prevents aqueous humor from flowing forward, thereby inducing ocular hypertension without requiring direct placement of occluding particles in the angle.
2Reliability
If microbeads are used to block aqueous outflow, then TOP elevation occurs, but the lengthy duration causes death of less than 30% of RGC, leaving a narrow window for testing
Solution Approach 1:
The patent changes the physical parameters of the occluding substance from heavy microbeads to lighter silicone oil with different density and viscosity properties. This parameter change results in more effective and sustained pupillary block, accelerating RGC death to over 80% within the same time frame, thereby extending the usable testing window for neuroprotectant evaluation.
3Reliability
If laser photocoagulation or hypertonic saline injection is used to induce ocular hypertension, then TOP increases, but technical challenges and irreversible tissue damage complicate interpretation
Solution Approach 1:
The patent converts the potential harm of silicone oil (which can cause glaucoma as a complication) into a beneficial experimental model. By intentionally injecting silicone oil to induce controlled ocular hypertension, the patent creates a reliable glaucoma model without the irreversible tissue damage associated with laser photocoagulation or hypertonic saline injection.
4Reliability
If silicone oil is used as tamponade in vitreoretinal surgery, then retinal detachment repair is achieved, but excess oil physically occludes the pupil causing secondary glaucoma
Solution Approach 1:
The patent applies partial occlusion rather than complete blockage. By injecting a controlled amount of silicone oil that occupies about 50% of the vitreous cavity, the patent achieves sufficient pupillary block to induce ocular hypertension while maintaining some aqueous circulation, thereby creating a controlled glaucoma model rather than complete obstruction.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This model effectively replicates human glaucoma by inducing significant retinal ganglion cell and optic nerve degeneration within weeks, providing a reliable and reproducible method for testing neuroprotectants and understanding glaucoma pathogenesis, with the ability to be adapted for various species and therapeutic applications.
Implementation Method 1
SO is lighter than the aqueous and vitreous fluids and an excess can physically occlude the pupil, which prevents aqueous flow into the anterior chamber
Implementation Method 2
This obstruction increases aqueous pressure in the posterior chamber and displace the iris anteriorly, which causes angle-closure, blockage of aqueous outflow through TM
Data Source
AI summary
Injection of silicon oil (SO) to the anterior chamber of an eye efficiently induces intraocular pressure (TOP) elevation. This effect occurs without causing overt ocular structural damage or inflammatory responses while simulating acute glaucomatous changes that human patients develop over years by inducing progressive RGC and ON degeneration and visual functional deficits within weeks. The anterior segments of the experimental eyes are not substantially affected, leaving clear ocular elements that allow easy and reliable assessment of in vivo visual function and morphology. More importantly, this is the only reversible ocular hypertension model by removing SO from the anterior chamber and particularly useful for testing neuroprotection treatment together with lowering TOP treatment. In summary, the acute ocular hypertension glaucoma model replicates secondary post-operative glaucoma. It is straightforward and reversible, does not require special equipment or repeat injections, and may be applicable to a range of animal species with only minor modifications.