What can be used to apply drops to a rat's eye? - briefly
A calibrated micropipette or a sterile ophthalmic applicator such as a glass capillary tube can deliver precise drops to a rodent’s eye. Both tools provide controlled volume and minimize trauma.
What can be used to apply drops to a rat's eye? - in detail
Delivering ophthalmic solutions to a laboratory rat requires devices that provide precise volume control, minimize stress, and protect the cornea. Commonly employed instruments include:
- Micropipettes with disposable tips – calibrated to 1–10 µL, allowing accurate dosing; tips can be angled to reach the ocular surface without contacting the eyelid.
- Hamilton glass syringes – 10–50 µL capacity, fitted with a fine stainless‑steel needle or blunt cannula; the needle is withdrawn before contact to avoid injury.
- Plastic single‑use droppers – pre‑filled or refillable, featuring a low‑volume tip that delivers a single drop; useful for quick administration when sterility is not critical.
- Capillary tubes – drawn to a specific length, holding a fixed volume; the tube is placed against the tear film and the solution is released by capillary action.
Key procedural considerations:
- Animal restraint – gentle manual hold or a restraining device that immobilizes the head while allowing access to the eye; avoid excessive pressure that could elevate intra‑ocular pressure.
- Corneal protection – apply a lubricating gel if the animal is under anesthesia to prevent desiccation; ensure the delivery device does not touch the cornea.
- Volume verification – calibrate the instrument before each session; confirm the delivered amount by weighing a test drop on a microbalance.
- Sterility – use sterile tips or syringes for each animal; discard reusable components after cleaning with ethanol and autoclaving.
- Administration technique – tilt the head slightly upward, pull the lower eyelid to form a pocket, and gently dispense the solution at the junction of the lid and globe; allow the animal to blink naturally to spread the fluid.
When high precision is required, a calibrated micropipette combined with a disposable tip provides the most reliable control. For routine dosing in larger studies, pre‑filled plastic droppers reduce handling time while maintaining acceptable accuracy. Selection of the appropriate tool should align with experimental goals, required volume, and animal welfare guidelines.