Synechiae in Cats

Synechiae is an eye condition that results in adhesion of the iris to either the cornea or the lens. Typically painful and irritating, it can have a large impact on a cat's quality of life. Thankfully, the problem is relatively straightforward to recognize and treat, meaning that owners who recognize the condition early on can minimize the impact that it will have on their cat.

The symptoms of synechiae are quite easy to spot. If your pet is experiencing several of the following, they may well be suffering from the condition:

• Excess production of tears
• Glaucoma or opacity of the lens
• Squinting or excessive blinking
• Inflammation of the uvea (noticeable via general redness/bloodshot iris)
• Increased sensitivity to bright light
• Failure of the pupil to dilate or contract in response to changes in light levels
• Lesions around the cornea

Types

There are two types of synechiae in cats, anterior and posterior, caused by adhesion to the cornea or lens respectively.

Synechiae in cats are most commonly caused by direct trauma to the eye or by bacterial infection. Fights as a result of territorial disputes are the most common direct cause of penetrating damage to the eye. Fortunately, however, these scuffles will often leave other superficial injuries that can prompt owners to check their pets for serious damage.

Although a characteristically misshapen pupil is one of the most definite indicators that your cat is suffering from synechiae, a vet should always be consulted before an accurate diagnosis can be made and treatment commenced.

When taking your pet to the vet, the practitioner will most likely diagnose the problem via a simple ophthalmic examination. Similar to eye tests humans undergo, the exam will consist of measuring the cat's response to light and its ability to focus on and track objects. The vet may also opt for an enhanced examination by introducing dyes into the eye to map any irregularities or they might decide to measure the fluid pressures of the eyeball using a tonometer.

The vet may have questions regarding your cat's daily routine and any substances/environments they may come into contact with on a regular basis. Obviously, if the condition is not caused by injury, then it is typically due to an infection and as such, identifying the source will make diagnosis and treatment easier.

In many cases, no treatment will be necessary, as the eye will eventually heal itself over time and return to normal. However, more direct methods could be necessary in certain circumstances.

Antibiotics/Antifungals

In the event of a particularly aggressive infection, it may become necessary for the vet to prescribe antibiotics. Typically, these will be given to you to administer at home and will take the form of either an eye drop or a pill. Whilst the pill can be mixed in with food, the eye drop can be more difficult to administer. Although a simple reward system can be used to entice the cat to cooperate with treatment, your vet may have specific advice on how best to proceed. Treatment times can vary from several weeks for a course of antibiotics to several months for antifungal drugs to do their work entirely.

Muscarinic Receptor Blockers

If your vet believes that there is a risk of further adhesion, they may decide to prescribe drugs that prevent the muscles that expand and contract the pupil from moving. This is to prevent further 'sticking' of the iris to the tissues of the cornea and lens as it comes into contact with them. These compounds are similar in nature to the drug atropine, which prevents involuntary muscle spasms, and the treatment typically delivered to animals in the form of an eye drop. Recovery times with this treatment will vary with the severity of the injury to the eye, but typically last approximately a month.

Surgery

If severe glaucoma appears, it may be necessary to perform laser surgery to remove the opaque tissue from the eye and remove the areas of the iris and lens/cornea that are adhering to one another. Surgery is the most drastic measure that can be taken, and as such will necessitate a long duration of follow-up visits and checkups to make sure the cat is healing well.

The chances of relapse are minimal when dealing with synechiae. Though if the condition is due to a bacterial infection, your vet may have advice on identifying and removing the threat if it is on your property in order to prevent re-occurrence.

It will be necessary to schedule follow-up appointments and examinations to make sure that the synechiae is healing and that the treatment is effective (if applicable). These examinations will also make sure that there are no complications following treatment. It may be a good idea to evaluate the general living arrangements of your pet (especially if they have contracted a fungal or bacterial infection), to make sure they are not being exposed to harmful environments that could be having an impact on their health. Be sure to consult with your vet before taking any additional steps.