TL;DR: A dark grey spot on a cat's eye is often a Feline Corneal Sequestrum; while not an immediate emergency, it requires veterinary care within 24 to 48 hours to prevent infection or eye rupture.
What causes a dark grey or brownish-black spot to appear on my cat's eye?
Noticing a change in your cat's eye can be alarming. A dark grey or brownish-black spot on the surface of the eye is most frequently identified as a Feline Corneal Sequestrum. This is a condition where a piece of the corneal tissue dies and becomes pigmented. It is often triggered by chronic irritation, such as feline herpesvirus or eyelashes rubbing against the surface. Other possibilities include iris melanosis (flat pigment spots) or corneal scarring from a previous injury.
How urgent is a dark spot on my cat's eye?
- The urgency level for a dark spot on the eye is Medium, meaning you should seek veterinary care within 24 to 48 hours.
- While not usually a midnight emergency, eye issues progress rapidly; seek help sooner if your cat is squinting, has discharge, or the eye looks cloudy.
- Untreated spots can lead to severe complications, including deep infections or the rupture of the eye.
Why should I provide a photo of my cat's eye for triage?
- Eye conditions are highly visual, and a high-resolution photo is a vital tool for an accurate triage assessment.
- Photos allow experts to see the exact depth and texture of the spot to determine if it is raised, flat, or pitted.
- This visual data helps differentiate between surface-level issues like a sequestrum and internal issues like a tumor.
- Providing a clear image ensures your cat is assigned the correct priority level for their veterinary appointment.
Clinical Context (Merck Veterinary Manual)
In cats, a dark spot on the eye may indicate a corneal sequestrum, which typically presents as a small, dark area within the anterior stroma. This lesion can enlarge, becoming dark brown or black, and is composed of necrotic stroma, vascularization, and surrounding inflammation. While variable pain is associated, the opacity is typically central to paracentral. Feline herpesvirus 1 is also associated with corneal sequestrum.
Chapter: Ophthalmology
Source: The Merck Veterinary Manual, 11th Edition (Page 494)