The importance of models in glaucoma research.

Experimental models have enhanced our understanding of the biology of glaucoma. Moreover, they have enabled the testing of potential therapies prior to the initiation of human trials. Each have advantages and limitations. In vitro cell and organ culture offer direct cellular accessibility and microenvironmental control, as well as efficient comparison between many experimental conditions or potential therapeutic compounds. However, they generally have less relevance to clinical glaucoma than in vivo models. Rat models allow moderate sized investigations of intact biological systems that have greater relevance to glaucoma than in vitro experiments, but less than primate experiments. Mouse models are similar to rat models but have the advantage of investigating mutant and transgenic strains mimicking specific aspects of glaucoma that are not available in other model systems. Primate models of glaucoma generally are the most relevant to human glaucoma but must be limited in scope because of availability and the high cost of experimentation.