Fatty Eye or Pea EyePea Eye
Pea eye (or fatty eye) is a permanent protrusion of the conjunctival sac, thought to be inherited. Pea eye and fatty eye are frequently grouped together by vets as conjunctival swelling. These conjunctival protrusions can be removed by laser if they are interfering with vision. Cavies with pea eye generally do not seem to be uncomfortable and treatment is usually not necessary.
VC Richardson, from CavySpirit.com describes a condition she calls 'red eye' that reportedly shows up under stress or in the presence of an irritant like smoke.
Fluid Retention and Pea Eye
In some cavies, pea eye may be caused or aggravated by fluid retention. Not all guinea pigs with heart conditions and pea eye show changes when using lasix but one owner observed that the pea eye always present in her pig with a heart condition (heart disease confirmed at autopsy) became much less noticeable after the animal was given lasix. She also observed a 50% reduction of pea eye for another pig (also with heart disease confirmed at autopsy) after 6 weeks of a low daily dose of Lasix. Her theory is that in some pigs, pea eye may be caused by fluid build-up due to poor circulation.
Treating Inflamed Conjunctiva
A reader's guinea pig with an inflamed conjunctiva was treated with flurbiprofen, an anti-inflammatory drop, and then gentamicin. The vet reasoned that by reducing the inflammation, the gentamicin could better treat the source of the infection. She found that antibiotic drops alone did not seem effective. The anti-inflammatory/antibiotic combination worked well and cured the problem for about three or four months, until it again returned.
"Cherry eye" in other animals generally refers to a gland located near the base of the 3rd eyelid that is pink in color rather than the normal white conjunctival color. Josephine, an author at GuineaLynx.com notes that there is no evidence of a guinea pig having a 3rd eyelid.
In a guinea pig, it is instead a lacrimal (tear producing) gland made up of lymphatic tissue and it is this gland which becomes infected and/or inflamed in cherry eye and prolapses. Cherry eye in dogs is considered uncomfortable, especially when the condition is more severe and covers more of the eye. In contrast, pea eye is usually not painful or uncomfortable.
"Cavies do have several lacrimal glands in the perimeter of the orbit. One called the glandula lacrimalis can become infected or inflamed and become more visible (prolapse). This may not be "Cherry Eye" per se, but I have not been able to find another term that is accurate to explain the situation. It does present in an identical manner...
"..."Cherry Eye" will only occur in the bottom "inside" corner of the eyes since that is where the lacrimal glands are located. Conjunctival or other swellings are a possibility all around the eye. Normally pea eye is found in the corners of eyes as well and can be due to subscleral fat in the region, but researchers are still finding many possible scenarios for pea eye.