Anisocoria in domestic cats (distribution, etiology, pathogenesis, diagnosis and therapy)

In cats, the pupil is located in the central part of the iris. The pupil is necessary for the correct passage of the light beam to the retinal area. In accordance with the amount of light, the pupil is able to expand or contract.

It is noteworthy that both pupils simultaneously dilate in a dark room with a lack of light and contract in bright light.

In cats, a pathology such as anisocoria may occur, characterized by a change in one pupil in relation to the other. One pupil is larger than the other. In rare cases, pathological constriction of the pupil is observed. As a rule, with anisocoria, the pathological pupil is dilated.

What is anisocoria?

In cats, the pupil is an elliptical hole in the middle of the iris that allows light to pass through the eyeball to the retina. The pupil constricts or dilates (enlarges) depending on the amount of light entering the eye, with both pupils typically dilating in dim light and constricting in bright light.

Anisocoria is a condition in which the two pupils of a cat's eye are different sizes.

; in other words, one pupil is larger than the other. In some cases, the abnormal pupil may be the one that is smaller, and in other cases, the abnormal pupil may be the one that is larger.

Tips for cleaning your cat's eyes

Although we have seen that the reasons why a cat has dilated pupils a lot and does not necessarily mean a lack of cleanliness, it is always advisable to maintain good hygiene in this part of the body to avoid irritation or problems caused by dirt. Here are some tips:

If the cat produces many legions, they should be removed every morning with sterile gauze and physiological serum or chamomile in its absence. It is good to fix the cleaning routine of the most delicate areas such as the eyes and ears. For adopted cats this is also important, always little by little and through positive reinforcement. If the hair around the eyes is too long, it needs to be trimmed to prevent it from getting into the eyes and causing damage. If your cat develops ocular discharge, inflammation, redness, or excessive itching, it should be taken to a veterinarian as soon as possible.

This article is for informational purposes only, we are not in a position to prescribe veterinary procedures or make any diagnoses. We invite you to take your pet to the veterinarian in case of any conditions or discomfort.

What causes anisocoria?

“Anisocoria occurs suddenly and you should seek veterinary attention immediately.”

Anisocoria is a symptom, and there can be several different causes, including:

• Corneal injuries, such as corneal ulcers
• Disease or damage to the brain or nerves leading to eye damage
• Glaucoma, a disease in which the pressure in the eyeball increases (the pupil in the affected eye will be dilated)
• Uveitis, or inflammation of the inside of the eye (the pupil in the affected eye will usually be narrowed)
• Retinal diseases
• Formation of scar tissue between the iris and lens (posterior synechia), a condition that can develop after uveitis
• Iris atrophy, or reduction in the amount of tissue in the iris, usually a degenerative change associated with aging
• A congenital iris defect in which the iris tissue does not develop properly
• Eye cancer
• Spasmodic pupil syndrome is a syndrome that may be associated with infection with feline leukemia virus.

If anisocoria occurs suddenly, you should treat it as an emergency and seek veterinary care immediately to reduce the chance that your cat's vision will be permanently lost.

Why does my cat have round pupils?

Having explained the function of the pupils in response to light, which is completely natural and typical for most animals, it is important to note that pupil dilation can also be due to other factors. So the answers to why your cat's pupils are dilated are numerous and may relate to situations or reactions to health problems. Focusing on these reasons associated with emotions and feelings, the cat’s round pupils express:

• Excitement: When an animal is very excited and nervous, such as during a play session, it is common to see round or elliptical pupils. However, excitement does not always occur due to positive stimuli, as it can also occur due to stress or anxiety.
• Satisfaction: In situations that create happiness, the cat will also dilate its pupils as a reflex. An example would be when we fill a food bowl.
• Fear: The cat has dilated pupils and eyes wide open. This is a clear sign of fear, which can be caused by change, loud noise, situation, etc.
• Aggression: Cats dilate their pupils when they look at their prey and prepare to attack, so if you look at yours in this way, you will feel threatened and consider defending yourself.

While some reasons for why a cat has round pupils are positive, it is important to note that this is not the usual way. In any case, dilatation indicates that the animal is not relaxed, and if it is due to him playing, we should not worry. But if we see dilated pupils most of the day, we should start to think that our cat is not healthy. It is possible that the animal is stressed by something and does not feel comfortable or safe, and it is our duty to find the reason that prevents it from restoring emotional stability.

On the other hand, it is important to emphasize that every cat is a world and can develop its own forms of communication, so dilated pupils are not always a reason for warning. By this we do not mean that we should not attach due importance to this, but it is important to know our cat, his character, behavior and reactions in order to learn how to identify the warning signal. Likewise, there are cat breeds with a predisposition to display elliptical or dilated pupils without causing an underlying problem, such as the British Shorthair.

How is the underlying cause of anisocoria diagnosed?

Your veterinarian will begin with a physical examination of your cat, including a detailed examination of the eye structures. Depending on these preliminary results, your veterinarian may perform additional, more specific testing. Your veterinarian ophthalmologist can measure tear production and intraocular pressure (pressure in the eyes) for each eye. The cornea may be stained with fluorescein dye to identify underlying corneal lesions or ulcers, and a conjunctival scraping or biopsy may be obtained and sent to a diagnostic laboratory for specialized testing. Blood tests may be performed to determine if the problem is due to a systemic disease such as feline leukemia.

In some cases, your veterinarian may recommend a referral to a specialized veterinary ophthalmologist for further diagnostic testing.

Consequences of injuries

When scarring of injuries occurs, opacities of varying intensity appear on the cornea. Because of this, insufficient light intensity reaches the retina. Behind the damaged cornea, the pupils reflexively dilate further to capture more light for improved vision. Although there is a reaction to light, it is very weak, and it seems that the pupils are constantly dilated.

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Blepharitis

Due to external influences or vitamin deficiency, inflammation of the eyelids develops. Consultation with a specialist is necessary to determine the type of disease. Blepharitis can be simple, meibomian, which is characterized by inflammation of the sebaceous glands on the eyelids, ulcerative. The main symptoms of the disease include: thickening of the eyelid, scratching around the eyes, crusts of pus on the surface, dilation of the pupil, and the cat suffers from severe itching.

First of all, the animal’s eyelids are freed from crusts using a solution of soda and oil. Vaseline oil is most effective for softening. The eyelids are treated with brilliant green and mercury yellow ointment. As an auxiliary therapy, the daily diet is enriched with Phytomins.

Проявление патологии при взрослении

РЈ взрослых непропорциональное SЂР°СЃС€РёСЂРµРЅРёРµ R·СЂР°С‡РєРѕРІ Р јРѕР¶РµС‚ быть следствием ІСЂРѕР¶РґРµРЅРЅРѕР№ Р° номалии. Еслв РѕРґРЅРѕРј глазу зрачок большой, Р° РІ РґСЂСѓРіРѕРј – RјР°Р»РµРЅСЊРєРёР№ , РЅРѕ это РЅРµ РґРѕСЃС‚ авляет дискомфорта, зрение РСРµ становвится S…уже, РЅРµ СЃ опровождается болевым Рё прочими SЃРёРјРїS ‚омами, анизокория РЅРµ представляет опасности. Если Сѓ взрослых РѕРґРёРЅ зрачок больше РґСЂСѓРіРѕРіРѕ RїРѕ RїСЂРёС‡РёРЅРµ опасного SЃРѕРїСѓС‚ствующего заб олевания, аномалия проявляется внезапно.

Зрачки разного размера

ПровоцирующРеРµ S„акторы – офтальмологические Рё РЅР µРІСЂРѕР»РѕРіРёС‡РµСЃРєРёРµ причины, почему диаметр Р·СЂР °С‡РєРѕРІ стал неодинаковым:

• СОнцефалит, опухоль головного РјРѕР·РіР°, аневризма СЃРѕСЃСѓР ґРѕРІ, менингит;
• шейный остеохондроз СЃРѕ сдавлвваннем нервных корешРєРѕРІ;
• воспалительный процесс РІ SЂР°РґСѓР¶РЅРѕР№ оболочке глаза;
• рубеоз – большой СЂРѕСЃС‚ СЃРѕСЃСѓРґРѕРІ РЅР° радужной оболочке;
• воспаленоцРеклклвоспаление переднего отдела СЃРѕСЃСѓРґРёС ЃС‚РѕР№ оболочки;
• глаукома – нарушение кровообращения ппитания глазнРѕРіРѕ нерва;
• SѓРІРµРёС‚ – заболевание SЃРѕСЃСѓРґРёСЃС‚РѕР№ оболочки органов Р·СЂР µРЅРёСЏ;
• имплантация линз, повреждение SЃС„инктера Рё радужки;
• повреждение волокон глазодвггательного нерва РЅРµРёС €РёРјРёС‡РµСЃРєРѕРіРѕ S‚РёРїР°.

RћСЃРјРѕС‚СЂ Сѓ офтальмолога

RљSЂРѕРјРµ S‚РѕРіРѕ, R°РхРѕѓР·РѕРєРѕСЂРёСЋ Sѓ RІР·СЂРѕСЃР»С‹С… РјРѕРіСѓС‚ SупровоцирРЕвать повышенне внутрвглазного давления, невргт глазного нерва, Ренфекционные процессы, скрытые генетические патологии, травмы РіРѕР» РѕРІС‹ Ре глаз, хирургЃческие операцРеРё РЅР° внутренних стр SѓРєС‚урах органов зрения.

Р' некоторых случаях РѕРґРёРЅ зрачок RјР°Р»РµРЅСЊРєРёР№, РґСЂСѓРіРѕР№ Р±РѕР »СЊС€РѕР№ бывает РІ результате паралича (пареза) плазодвггательного нер PIP°. Наступает как следствие аневризмы, инсульта, РІРѕСЃРїР° ления оли опухоли. Если зрачок стал замедленно SЂРµР°РіРѕЂРѕРІР°С‚СЊ РЅР° свет, РїСЂРѕР ±Р»РµРјР° может Р·Р °РєР»СЋС‡Р°С‚СЊСЃСЏ РІ сдавливанви глазодвггательного нерва. Прием лекарственных препаратов Рё использование РѕС„ S‚альмологических мазей – ещ Рµ РѕРґРЅР° РїСЂРёС‡РеРЅР°, почему RѕРґРЅР·СЂР°С‡РѕРє стал больше. RќРѕ SЌS‚Рѕ SЏРІР»РµРЅРёРµ RєСЂР°С‚РєРѕСЃСЂРѕS‡РЅРѕРµ SЃ RѕS‡РµРІРёРґРЅС‹Рј фактоS ЂРѕРј, спровоцировавшим SЂР°СЃС€РёСЂРµРЅРёРµ R·СЂР°С‡РєР°.

Treatment

Treatment is based on eliminating the primary disease , and different drugs and techniques may be used .

Know! In case of anisocoria, expressed as an enlargement of the pupil by 2 millimeters or more, treatment is carried out by a neurologist, since such serious deviations indicate a neurological etiology of the disorder.

If there are physiological abnormalities due to injury or if there is a congenital anomaly, surgery may be necessary.

Symptoms of the disease

Alarming symptoms include the following anomalies:

• blurred vision;
• photophobia;
• double vision;
• migraine;
• fever;
• acute pain syndrome in the eyes;
• nausea, less often – vomiting;
• torticollis;
• partial loss of vision;
• decline in performance.

If one pupil is slightly larger than the other, then this abnormal condition is immediately visible. At first, the patient may not pay attention to such a cosmetic defect, but subsequent symptoms raise serious concerns for his vision.

If such discomfort prevails, it is necessary to urgently seek qualified help from an ophthalmologist. If we are talking about a childhood disease, then the difference in pupils is already a good reason to go to a specialist.