Entropion is a common eye problem in dogs and usually is clinically obvious, even in young puppies. However, there are several diagnostic procedures that are used by veterinarians to differentiate entropion from other eye or eyelid disorders, such as distichiasis (the presence of a double row of eyelashes, one or both of which are turned inward against the eyeball, causing friction, irritation and severe, chronic damage to the eye) and trichiasis (where normally placed lashes or facial hair are ingrown, irritating the cornea and conjunctiva).
By definition, entropion is a rolling inward of all or part of an eyelid edge. Diagnosis is not difficult and normally is based simply upon the dog’s breed, history and clinical presentation, without further testing. Of course, the veterinarian still will perform a thorough physical examination of the dog to be sure that the diagnosis of entropion is correct.
In order to distinguish entropion from other conditions, and to help determine the cause of the condition in non-predisposed breeds, the attending veterinarian will perform a complete ophthalmic examination. This involves a Schirmer tear test, application of fluorescein dye, assessment of intraocular pressures and a thorough examination of the physical structure of the eyelids, eyelashes, cornea and conjunctiva. The best way to distinguish entropion from blepharospasm, which is severe squinting and spasms of the muscles around the eye, is to apply anesthetic eye drops. The eyelids of dogs with blepharospasm caused by pain will return to normal, because the anesthetic drops will temporarily relieve eye pain. The eyelids of dogs with entropion will not be corrected by topical anesthetics.
These various eye examinations will be done while the dog is in a relaxed state. Excessive restraint or manipulation of the dog’s head can exaggerate the degree of entropion when it is present. Ophthalmic tests are not particularly invasive and do not require general anesthesia; application of topical anesthetic drops are usually all that is necessary to ensure the dog’s comfort. Depending upon the examination results, the veterinarian may recommend advanced testing and may refer the patient to a veterinary eye specialist.
Routine blood work (a complete blood count [CBC] and a serum chemistry panel), along with a urinalysis (UA), may be suggested as well, as part of a thorough work-up of the dog’s health. However, the results of these tests will not disclose the cause of entropion in any particular dog.