How can you tell if a rat is going blind? - briefly
Rats losing sight repeatedly bump into cage walls, move hesitantly, and exhibit absent or delayed pupil constriction when exposed to light. Other signs include cloudy corneas, excess tearing, and a failure to respond to visual stimuli.
How can you tell if a rat is going blind? - in detail
Rats that are losing vision display several observable signs.
- Changes in navigation: The animal hesitates at corners, crashes into cage walls, or runs into objects that were previously avoided.
- Altered grooming: Scratching or rubbing around the eyes becomes more frequent, and the rat may miss its own face when cleaning.
- Pupil abnormalities: Pupils may appear dilated, irregular, or fail to constrict in response to light. A lack of the normal light reflex indicates compromised retinal function.
- Reduced response to visual cues: The rat does not react to moving shadows, sudden light changes, or food placed visibly in the enclosure.
- Eye surface issues: Cloudiness, cataract formation, or discharge suggest underlying ocular disease that can lead to blindness.
Diagnostic procedures complement visual observation.
- Direct ophthalmoscopy: Allows examination of the retina, optic nerve, and lens for degeneration or cataracts.
- Electroretinography (ERG): Measures electrical activity of retinal cells; diminished amplitudes confirm functional loss.
- Obstacle course test: A simple maze with clear visual markers assesses the animal’s ability to navigate using sight alone. Failure to locate the markers while other senses remain intact points to visual impairment.
When multiple signs appear together—especially navigation errors, absent light reflex, and ocular opacity—blindness is highly probable. Early detection enables veterinary intervention, which may slow progression or improve quality of life through environmental adjustments.