Contributions of aquatic organisms to understanding the vertebrate ocular lens

Aquatic species have played a vital role over the past 200 years in detailing the structure, physiology, development, and evolution of the ocular lens. As a living piece of biological "glass", the lens must balance the optical demands of transparency and refractive power with the requirements of a metabolically active tissue. Lens researchers have leveraged unique aspects of aquatic species, such as 1) the lack of corneal refraction and the simplification of modeling aquatic lens optics, 2) the presence of external embryos for real-time observation of eye and lens development, and 3) the diversity of habitats, ecology, and genetics that support comparative studies. Discoveries across many areas of aquatic lens research contribute to understanding human blindness, tissue aging and regeneration, optical and protein design, and fundamental features of cell biology relevant to many tissues. This review highlights key contributions in these areas and points to possible future areas of discovery.