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Updated: Dec 5, 2025
Small Molecule Screening and Toxicity Testing in Early-stage Zebrafish Larvae
Published on: March 7, 2025
Zebrafish as an Animal Model for Ocular Toxicity Testing: A Review of Ocular Anatomy and Functional Assays
Steven Cassar1, Christina Dunn1, Meg Ferrell Ramos1
1Preclinical Safety, 419726AbbVie, Inc, North Chicago, IL, USA.
Abstract:
Xenobiotics make their way into organisms from diverse sources including diet, medication, and pollution. Our understanding of ocular toxicities from xenobiotics in humans, livestock, and wildlife is growing thanks to laboratory animal models. Anatomy and physiology are conserved among vertebrate eyes, and studies with common mammalian preclinical species (rodent, dog) can predict human ocular toxicity. However, since the eye is susceptible to toxicities that may not involve a histological correlate, and these species rely heavily on smell and hearing to navigate their world, discovering visual deficits can be challenging with traditional animal models. Alternative models capable of identifying functional impacts on vision and requiring minimal amounts of chemical are valuable assets to toxicology. Human and zebrafish eyes are anatomically and functionally similar, and it has been reported that several common human ocular toxicants cause comparable toxicity in zebrafish. Vision develops rapidly in zebrafish; the tiny larvae rely on visual cues as early as 4 days, and behavioral responses to those cues can be monitored in high-throughput fashion. This article describes the comparative anatomy of the zebrafish eye, the notable differences from the mammalian eye, and presents practical applications of this underutilized model for assessment of ocular toxicity.
Insights
Zebrafish offer a valuable alternative model for assessing ocular toxicity, complementing traditional animal studies. Their similar eye structure and rapid visual development enable high-throughput screening of chemical impacts on vision.
Area of Science:
- Toxicology
- Ophthalmology
- Comparative Anatomy
Background:
- Understanding xenobiotic-induced ocular toxicities is crucial for human, livestock, and wildlife health.
- Traditional mammalian models (rodents, dogs) have limitations in detecting subtle visual deficits.
- The zebrafish eye shares anatomical and functional similarities with the human eye.
Purpose of the Study:
- To explore the utility of zebrafish as an alternative model for ocular toxicity assessment.
- To compare the anatomy of zebrafish and mammalian eyes, highlighting key differences.
- To present practical applications of zebrafish in toxicological studies of vision.
Main Methods:
- Comparative anatomical analysis of zebrafish and mammalian eyes.
- Review of existing literature on ocular toxicants in zebrafish.
- Discussion of high-throughput behavioral monitoring in zebrafish larvae.
Main Results:
- Zebrafish eyes are anatomically and functionally similar to human eyes.
- Common human ocular toxicants have shown comparable toxicity in zebrafish.
- Zebrafish larvae exhibit rapid visual development and measurable behavioral responses.
Conclusions:
- Zebrafish represent an underutilized yet valuable model for assessing functional vision impacts from xenobiotics.
- This model offers advantages for high-throughput screening with minimal chemical use.
- Zebrafish studies can enhance our understanding of ocular toxicity across species.
