Abstract
Purpose:
The purpose was to develop and combine various non-invasive ocular assessment techniques in zebrafish. Once a technique was developed, a brief comparison study was conducted with eye disease models. The described techniques would be useful for determining future ocular assessments for zebrafish disease models and their respective treatments.
Methods:
Zebrafish were raised under normal conditions. Visual acuity (VA) was measured using the zebrafish’s optokinetic response. Briefly, the fish track progressively smaller gratings until tracking can no longer be elicited. Intraocular pressure (IOP) was measured using a blood flow analyzer pneumotonometer. Fish were anesthetized in tricaine and the IOP was taken by pressing the probe against the fish’s eye with a micromanipulator. Optical coherence tomography (OCT) was performed similarly to the IOP using a commercially available clinical OCT. Finally, fundus imaging and gonioscopy were performed using a small 2mm gionioscopy lens and a stereomicroscope.
Results:
A critical observation was that several of the techniques served to corroborate another. A poor VA could be explained by a cataract visualized in both the OCT and gonioscopy examination. When comparing ocular characteristics for bugeye zebrafish, a glaucoma/myopia model, a combination of OCT, gonioscopy, and IOP were used to demonstrate that the pupil was constricted and the lens pushed back into the vitreous. However, the lens was still significantly farther from the retina compared to wildtype. Additionally, several differences between ocular parameters were noted between different wild-type strains.
Conclusions:
Using multiple non-invasive ocular assessments in zebrafish can be useful in characterizing subtle differences in wildtype and disease models. Importantly, individual zebrafish can be monitored longitudinally; reducing the total number of fish needed for certain vision studies. Because difference were noted between several strains of fish, it is important to take those into consideration when developing a disease model to study or comparing one strain to another.
Keywords: 754 visual acuity •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
472 comparative anatomy