Standard Operating Procedures for Common Laboratory Animal Ocular Procedures

Immunology and Pathology in Ocular Drug Development

“…Anterior chamber dimensions of some species such as mice and rats preclude the IC administration of a certain volume and may not accommodate a solid injectable implant because the ACV are small and the AC depths (ACD) are relatively shallow. 98 In rabbits, cats, dogs, pigs, and NHP, the ACV and ACD are great enough to accommodate larger volumes of drug Injection sites for intracameral (IC) and intravitreal (IVT) drug delivery. Intracameral injection: needle entry into the anterior chamber through clear cornea adjacent to the limbus (corneoscleral junction) in the superotemporal quadrant with the needle positioned parallel to the iris plane and needle bevel facing the cornea to avoid injecting the drug solution or implant toward the anterior surface of the iris, the needle tip does not extend to the pupil to avoid contact with the anterior lens capsule.…”

“…H&E stained section of a dog eye. solutions, 98,99 but their ICA dimensions may not be large enough to accommodate a solid drug implant designed to fit within the internal limbus at the opening of the human ICA. The relevant ICA size parameters for determining whether an angle can accommodate an implant are AC angle, angle opening distance, and angle recess area.…”

“…Common consequences of IC injections include physical tissue injury from the needle injection and implant placement, hemorrhage (hyphema), and infectious endophthalmitis. 98 The immunopathology of wound healing subsequent to IC injection-related injury is discussed below. The immunopathology of endotoxin introduction and infectious endophthalmitis is addressed in the sections for innate immunity and the posterior segment.…”

“…Anterior chamber dimensions of some species such as mice and rats preclude the IC administration of a certain volume and may not accommodate a solid injectable implant because the ACV are small and the AC depths (ACD) are relatively shallow. 98 In rabbits, cats, dogs, pigs, and NHP, the ACV and ACD are great enough to accommodate larger volumes of drug solutions, 98,99 but their ICA dimensions may not be large enough to accommodate a solid drug implant designed to fit within the internal limbus at the opening of the human ICA. The relevant ICA size parameters for determining whether an angle can accommodate an implant are AC angle, angle opening distance, and angle recess area.…”

“…Insertion site and technique varies slightly with species. 183 For NHPs, the needle should be inserted into the sclera at a 15° to 30° angle, 2 to 3 mm posterior to the temporal limbus (either inferior or superior), and then angled 45° to 60°, extending needle insertion 4 to 6 mm into the vitreous 183 (Figure 5). Understanding the physical nature of the vitreous and its role in maintaining ocular health is important to successful development of therapies intended for this space.…”