Slit Lamp-Based Ocular Scoring Systems in Toxicology and Drug Development: A Literature Survey.

PURPOSE: To present a survey of the features of published slit lamp-based scoring systems and their applicability in the context of modern ocular toxicology and drug development.

METHODS: References describing original or modified slit lamp-based scoring systems for human or veterinary clinical patients or in investigative or toxicologic research were collected following a comprehensive literature review using textbooks and online publication searches. Each system's indications and features were compiled to facilitate comparison.

RESULTS: Literature review identified 138 original or modified scoring systems. Most (48%) were published for evaluation of the ocular surface, 34% for the general anterior segment, and 18% for the lens. Most systems were described for assessment of human patients (50%) and small albino laboratory species such as rabbits (19%), rats (12%), and mice (8%). Systems described for pigmented laboratory species and for larger species such as dogs, cats, pigs, and nonhuman primates (NHPs) were comparatively underrepresented. No systems described a lens scoring scheme specific to the dog, cat, pig, or NHP. Scoring schemes for aqueous and vitreous cells were infrequently described for laboratory species.

CONCLUSIONS: Many slit lamp-based scoring systems have been published, but the features of each differ and complicate translation of findings between different species. Use and interpretation of any scoring system in toxicology and drug development must be done with awareness of the limitations of the system being used.