Post by angelwyche - ADMIN on Dec 17, 2007 22:45:41 GMT
Guinea Pig Anatomy
The Eye
The Eye
The eyes of a guinea pig are often its most attractive physical characteristic. In good health they are bright and large, slightly protruding from each side of the head, and are usually of the same size. The eyes can be of 3 main colours; pink, ruby or dark – dark can mean black with a ruby cast, brown or blue.
Guinea pigs can sleep with their eyes open, very rarely do the sleep with their eyes fully closed. Their vision is poor, but they can detect some colour.
Basic structure of a mammalian eye
The structure of the mammalian eye owes itself completely to the task of focusing light onto the retina. All of the individual components through which light travels within the eye before reaching the retina are transparent, minimizing dimming of the light. The cornea and lens help to converge light rays to focus onto the retina. This light causes chemical changes in the photosensitive cells of the retina, the products of which trigger nerve impulses which travel to the brain.
Light enters the eye from an external medium such as air or water, passes through the cornea, and into the first of two humours, the aquaus homer Most of the light refraction occurs at the cornea which has a fixed curvature. The first humour is a clear mass which connects the cornea with the lens of the eye, helps maintain the convex shape of the cornea (necessary to the convergence of light at the lens) and provides the conical endothelium with nutrients. The iris between the lens and the first humour, is a coloured ring of muscle fibres. Light must first pass though the centre of the iris, the pupil. The size of the pupil is actively adjusted by the circular and radial muscles to maintain a relatively constant level of light entering the eye. Too much light being let in could damage the retina; too little light makes sight difficult. The lens, behind the iris, is a convex, springy disk which focuses light, through the second humour, onto the retina.
What can go wrong.
There are a number of problems that can have an affect on your guinea pigs eye/s. Anything that you notice out of the ordinary involving the eyes and the surrounding tissues, consult your vet as soon as you can.
Poke or foreign object injuries
The most common problem is usually damage or something in or poking the eye causing injury. If it is a piece of hay or a hay seed it may still be in there.
The symptoms are; swelling of the eye and possibly the area surrounding the eye, discoloration of the eye i.e. blood shot eyes, milky appearance of the eyes, guinea pig paws and scratches at the eyes. Discharge from the eyes, may be also a discharge from the nose.
While waiting to get your appointment at the vet cleanse the eye carefully with saline solution (you can buy little sachets of sterile 0.9% saline at the chemist, always useful to have around) You can also use broline or golden eye drops from the chemist. These are mildly antiseptic.
Infection
Can set in as a result of of an injury, or spontaneously.
Again you will see swelling and discoloration.
Dry crusty eyes
Along with eyes that look small, can be an indication of dehydration. Your guinea pig may be very ill, contact a vet.
Allergies
Discharge from the eyes along with a discharge from the nose. There will likely be inflammation and the guinea pig may scratch at his eyes. Treatment is identifying the substance responsible and removing it away from your guinea pigs environment. Culprits are generally the type of bedding used, a cleaning agent or a room scenter or aerosol.
Chlamydia
A nasty infection that is carried by biting insects and by close contact with an infected guinea pig. The problem itself is very difficult to cure. Chlamydia is a self limiting infection, but the symptoms can be eased.
Symptoms are swollen eyes, but it may just affect one eye, redness, inflammation of the tissues around the eye. Severe irritation may cause the guinea pig to scratch at his eyes. Maybe causing self trauma and even blindness and loss of the eye. Bathing eyes carefully 2 x daily, or more regular if needed. Anti inflammatory eye drops will help ease the symptoms. Antibiotic drops may also help.
Other symptoms of this nasty illness are lack of appetite, dull staring coat, Pregnant sows may miscarry and become very ill.
Secondary pneumonia may set in needing antibiotic treatment.
Fatty Eye
This is normally just cosmetic. The lower eyelid droops exposing some of the fatty tissue below the eye. Everything else about the eye stays normal. This causes no harm but is a disqualification on the show table.
Cataracts
The pupil of the eye looks reflective and mirror-like, will cause partial to complete blindness.
This is normally a problem of old age, but it can also be genetic and youngsters may inherit this.
The Teeth Connection
Discharge from the eyes may also be a sign that some thing is not right with the teeth. Sometimes an problem with the molars can affect the tear duct, blocking it. So it is worth while getting your vet to look into the guinea pigs mouth and check for inflammation, dental growth problems or infection.

coppyrights © angelwyche
