The definitive diagnosis of Sudden Acquired Retinal Degeneration Syndrome (SARDS) relies on a specific advanced test.
The Key Diagnostic Method: Electroretinography (ERG)
According to veterinary ophthalmologists, the only way to definitively diagnose SARDS is with a test called electroretinography (ERG).
While a dog with SARDS will typically show sudden blindness and often have retinas that appear normal during a standard ophthalmic exam, the ERG test reveals the underlying issue.
What the ERG Test Involves:
- The test measures the electrical responses of the retina's photoreceptor cells (rods and cones) when stimulated by light.
- It involves flashing a bright light in front of the eye.
- Specialized equipment monitors and records the electrical activity of the retina.
How ERG Confirms SARDS:
- In a healthy eye, the retina produces characteristic electrical signals in response to light.
- In an eye affected by SARDS, even though the retina may look normal externally, the photoreceptor cells are no longer functioning correctly.
- The ERG test will show severely reduced or non-existent electrical activity in the retina, confirming the diagnosis of SARDS.
Therefore, although clinical signs like sudden blindness and changes in behavior might suggest SARDS, the ERG test is essential to confirm the diagnosis definitively by assessing the retina's functional status.
