Periodic Ocular Inflammation in Horses: Cause, Symptoms, Diagnosis, Treatment

What is periodic ocular inflammation in horses?

➡️ Video tip: In this video you will learn what a periodic eye inflammation and what measures are necessary.
Trigger warning: The following video contains explicit footage from the operating theater!

Equine recurrent uveitis (ERU), also known as periodic ocular inflammation or moon blindness, is the most common eye disease in horses and affects around 12% of the equine population worldwide. Documented since the Middle Ages, it is a disease characterized by recurrent episodes of inflammation of the skin of the horse's eye. These episodes typically increase in intensity over time and can lead to irreversible damage and ultimately blindness in the horse if no timely countermeasures are taken.

The exact causes of chronic eye inflammation in horses are not yet fully understood, but researchers suspect an autoimmune disease in which the horse's immune system reacts hypersensitively to certain triggers. Bacteria of the genus Leptospira, which can be transmitted via contaminated rodent urine, play a possible role. Other risk factors include genetic predispositions, particularly in horses with special color genes such as Appaloosas, Cremellos and tiger pintoes.

The progressive nature of periodic ocular inflammation makes early diagnosis and targeted therapeutic measures essential. Horse owners should seek veterinary advice immediately at the first signs such as watery eyes in the horse, sensitivity to light or redness. In addition to treating acute inflammation, preventative measures such as regular check-ups and good stable hygiene play a key role in dealing with periodic ocular inflammation in horses.

Raising awareness of this eye disease in horses among horse owners and veterinarians is crucial to maintaining the quality of life of affected animals. A comprehensive understanding of eye diseases in horses can help to prevent irreversible damage at an early stage.

Causes of periodic ocular inflammation in horses

Periodic ocular inflammation (equine recurrent uveitis, ERU) is a complex disease that can be triggered by various factors. It is regarded as a multifactorial disease in which autoimmune reactions, infections with leptospires and genetic predispositions all play a role.

Autoimmune disease

In regions such as North America and the UK, periodic ocular inflammation in horses is often regarded as an autoimmune disease. The horse 's immune system attacks the body's own tissue, which leads to recurring inflammation in the horse's eye.

Leptospira infection

In Germany, infection with leptospires is often discussed as the main cause of periodic ocular inflammation in horses. These bacteria, which are mainly transmitted by rodents such as rats and mice, enter the horse's body via contaminated feed or water. Almost every horse comes into contact with leptospires in the course of its life, but only in a few horses do the bacteria actually enter the eye and cause chronic ocular inflammation in the horse. This incubation period can last several months to years before symptoms of the eye disease become visible in the horse.

Genetic predisposition

Another important factor is genetic susceptibility. Horse breeds such as Appaloosas and Knabstruppers, which often have a tiger pinto pattern, are particularly susceptible to periodic ocular inflammation in horses. This disease also occurs more frequently in cremellos, pintoes and blacks, which indicates a genetic component.

Periodic ocular inflammation in horses is one of the most common and most serious eye diseases in horses. It is caused by the interaction of autoimmune reactions, infections (especially with leptospires) and genetic factors. Early recognition of the symptoms of periodic ocular inflammation in horses and targeted treatment measures are crucial to prevent the progression of this disease.

Symptoms of periodic ocular inflammation

Periodic ocular inflammation in horses, also known as equine recurrent uveitis (ERU) or colloquially moon blindness, is a recurring inflammation of the inner eye structures. If left untreated, it can lead to blindness. Early recognition of the symptoms is crucial for effective treatment.

The following table provides a detailed overview of the most common symptoms that can occur with equine recurrent uveitis. Each symptom is explained to help both recognize the disease and understand its implications. This information is particularly helpful in recognizing early signs and acting accordingly.

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Diagnosis and veterinary examinations

The diagnosis of periodic ocular inflammation requires a thorough veterinary examination and specific diagnostic tests. To diagnose the disease, the veterinarian inquires about the horse's medical history (anamnesis) and performs an examination of the inner eye. At the first manifestation, only inflammation of the inner eye can be detected. The term ERU(equine recurrent uveitis) can only be used if the inflammation recurs. In practice, however, it is assumed that it is a case of uveitis as long as the opposite is not proven.

In addition to the medical history, a thorough examination of the eye is required for the clinical diagnosis. In order to detect an infection with leptospires, the vet takes aqueous humor samples from the horse under sedation and local anesthesia in the clinic, which are then tested for antibodies or antigens in the laboratory. Alternatively, a rapid test can be carried out by the vet directly in the stable (snap lepto). As part of a doctoral thesis, the reliability of the rapid test was compared with established testing methods. The result showed that the rapid test is sometimes more reliable than other methods.

Treatment for periodic ocular inflammation

➡️ Video tip: In this video you will learn how a periodic eye inflammation is treated.
Trigger warning: The following video contains explicit footage from the operating theater!

If the recognition stage of equine periodontitis is identified early, anti-inflammatory ointments or drops, often containing cortisone, or antibiotics in the case of bacterial infection will be prescribed. Prompt intervention at this stage can help to mitigate the progression of the disease and minimize irreversible damage.

In the advanced stage of periodontitis, when the inflammation is already well advanced, muscle paralyzing and pupil dilating drugs are used. These drugs aim to reduce pain and prevent the eyes from sticking together, which is particularly important to improve the horse's well-being.

In addition to these measures, corticosteroids, either administered intravenously or injected directly into the conjunctiva during particularly severe flare-ups, can also be used to combat inflammation. A catheter can also be used to facilitate eye irrigation and the administration of medication.

Modern technologies also offer the possibility of placing an implant with virus-inhibiting active ingredients in the horse's eye. These implants release the required amount of active ingredient over a longer period of time, which can reduce the need for drops or ointments.

For severe cases, vitrectomy is available as a surgical measure. During this operation, the vitreous body in the horse's eye is cut up and removed, eliminating inflammation and opacities. This can lead to a considerable improvement in vision.

In cases where a horse is already blind, it may be necessary to remove the painful eye under general anesthesia. This not only relieves the pain, but also allows the horse to regain its zest for life.

It is important to emphasize that horses can cope surprisingly well with partial or total blindness. After a short acclimatization phase, most horses are able to orient themselves well and lead a full life. All these measures are, of course, carried out under sterile conditions in specialized equine clinics.

We accompanied a day in the operating room during a periodic ocular inflammation.
‍Trigger warning: The following video contains explicit footage from the operating room!

Preventive measures

Periodic ocular inflammation, also known as equine recurrent uveitis (ERU), is one of the most common causes of blindness in horses. Although complete prevention is not possible, there are effective measures to reduce the risk of occurrence or recurrence of this serious condition. Below you will learn the best strategies for prevention and how to protect your horse's long-term eye health.

Hygiene and stable management

One of the main causes of moon blindness are leptospires, bacterial pathogens that are often transmitted by rodents. To minimize the risk, the following measures should be observed:

• Rodent control: Keep the barn free of mice and rats by storing food securely and locked away.
• Cleanliness in the barn: Regular removal of manure and dirt prevents the accumulation of bacteria and parasites.

Regular veterinary checks

Early diagnosis is crucial to slow down or stop the progression of the disease. Have your horse's eyes checked regularly by a vet, especially when the first symptoms such as tearing, sensitivity to light or redness appear.

Protection from UV radiation

Strong sunlight can irritate the eyes and promote relapses of ERU. Therefore, horses that are susceptible to moon blindness should be protected:

• Eye protection masks: Use special masks that block UV radiation while maintaining your field of vision.
• Shading in the barn: Make sure that there are enough shady areas available.

Vaccinations and worming

Horses with moon blindness can react sensitively to vaccinations and worming treatments. It is therefore important:

• Consult your vet: Plan vaccinations and worming carefully and discuss them in detail to avoid possible complications.

Strengthening the immune system

A strong immune system can reduce the risk of inflammatory diseases. Watch out for:

• Balanced nutritionFeed your horse high-quality hay and supplement the diet with vitamins such as A, E, C and B12.
• Zinc and seleniumThese trace elements support the immune system and the healing of inflammatory processes.

The prevention of periodic ocular inflammation requires a combination ofgood stable hygiene, regular veterinary checks and targeted protective measures. A balanced diet and strengthening the immune system also play a crucial role. Although these measures do not offer absolute protection, they can significantly reduce the risk and improve your horse's quality of life.

Case studies and success stories

Periodic ocular inflammation, also known as moon blindness, is a serious and recurring inflammation of the eye that can lead to blindness if left untreated. However, numerous case studies and success stories show that with the correct diagnosis and treatment, there is hope for affected horses. Below you will find an overview of selected cases, treatment approaches and results achieved.

Success stories from the field

1. Case study: Dreamline, a 6-year-old warmbloodAwarmblood named Dreamline was suffering from a chronic eye disease diagnosed as ERU. At a renowned equine clinic, a combination of drug therapy(cortisone and painkillers) and surgery was used to control the inflammation. Thanks to vitrectomy - a procedure in which the vitreous body of the eye is removed - Dreamline was stabilized in the long term. The case shows that early intervention is crucial.
   Source: Equine Clinic
2. Long-term management of a chronic diseaseAfield report documents a horse owner's eight-year battle with his horse's disease. In addition to conventional medical treatments, such as anti-inflammatory eye drops, eye protection was used to protect the horse from UV radiation. The owner reports that the disease was brought to a halt by continuous care and emphasizes the importance of regular veterinary check-ups.
   Source: Joy With Horses
3. Veterinary practice: combination of conventional medicine and naturopathyA veterinary practitioner documented the case of a horse with moon blindness in which alternative methods such as acupuncture and homeopathic remedies were used in addition to conventional medical treatments. This holistic approach helped to improve the horse's quality of life.
   Source: Paracelsus Magazine

Hope for affected horse owners

The success stories mentioned above make it clear that the treatment of periodic ocular inflammation depends heavily on the individual situation. While surgical interventions such as vitrectomy often help in the long term, supportive measures such as eye protection or naturopathic approaches can significantly improve quality of life.

Early diagnosis and customized therapy are crucial for success in the treatment of ERU. The combination of modern medicine and alternative approaches offers many horses the chance of a pain-free life. These success stories encourage horse owners to thoroughly investigate treatment options and work with their vet to find the best solution.

Tips for horse owners when dealing with periodic ocular inflammation

Horse owners play a crucial role in the management and care of horses with periodic ocular inflammation.

• Early detection of symptoms

Attention to early signs enables faster intervention and improves the chances of successful treatment.

• Cooperation with a veterinarian

Close cooperation with an experienced veterinarian is crucial for an accurate diagnosis and an individual treatment plan.

• Care and management at home

Proper eye care, management of environmental factors and adherence to prescribed treatment plans will help to promote the well-being of the horse.

Periodic ocular inflammation in horses: In summary

In conclusion, it is crucial to understand the complexity of this disease and at the same time raise awareness of the importance of comprehensive care and prevention.

Knowledge of periodic ocular inflammation and its many causes, from genetic factors to environmental influences and infections, lays the foundation for targeted treatment and prevention. Horse owners, vets and breeders can improve the quality of life of affected animals by recognizing the symptoms early and working closely together.

The constant development in veterinary medicine opens up new perspectives for the treatment of periodic ocular inflammation. Research approaches could lead to innovative therapeutic options that enable even more targeted and effective treatment. Collaboration between veterinarians, breeders and researchers is crucial to achieve progress in the treatment and prevention of this disease.

Horse owners play a central role in dealing with periodic ocular inflammation. Implementing preventative measures such as genetic selection, regular grooming and environmentally friendly management can not only help to minimize the risk but also improve the quality of life of horses.

The tips outlined in the article provide specific guidance for horse owners. Early recognition of symptoms, close cooperation with a vet and careful care and management at home are key elements in maintaining the animal's quality of life.

It is not only a medical challenge, but also an ethical obligation to ensure that horses affected by this disease receive the best possible care. Ongoing research and collaboration between all parties involved provide a promising basis for optimized care of horses with periodontal ocular inflammation in the future.

Periodic eye inflammation: The most important questions and answers

Is periodic ocular inflammation in horses contagious?

‍Periodicocular inflammation itself is not directly contagious. However, certain pathogens such as leptospires, which are a possible cause, can be transmitted through contaminated water or food.

Can periodic ocular inflammation in horses be cured?

‍Acomplete cure is rare, but with appropriate treatments, such as vitrectomy, the symptoms can be controlled and the horse's quality of life significantly improved.

Where does periodic ocular inflammation in horses come from?

‍Thedisease can be triggered by various causes, including bacterial infections (e.g. leptospires), autoimmune reactions, genetic predisposition and environmental factors such as UV radiation.

How do I recognize periodic ocular inflammation in horses?

‍Typicalsigns include increased lacrimation, sensitivity to light, pain, swollen eyelids and a cloudy cornea. Horses may also exhibit conspicuous behavior such as rubbing their eyes or avoiding light.

How does periodic ocular inflammation manifest itself in horses?

‍Itmanifests itself through recurring bouts of inflammation that cause symptoms such as redness, tearing, swelling and sensitivity to light. In the chronic course, permanent damage such as lens opacity or blindness can occur.

What is a vitrectomy in horses?

‍Vitrectomy is a surgical procedure in which the inflamed vitreous is removed from the eye. This can reduce episodes of inflammation and slow down the course of the disease.

What does a cloudy eye mean in a horse?

‍Acloudy eye can be an indication of periodic eye inflammation. It often indicates inflammation or damage to the cornea or the eye as a whole and should be examined by a vet.

How does periodic ocular inflammation develop in horses?

‍Thedisease is caused by a complex combination of genetic factors, infections (e.g. caused by leptospires) and environmental factors such as UV radiation or trauma.

How do you recognize periodic ocular inflammation in horses?

‍Inaddition to the visible symptoms such as lacrimation, swelling and clouding, conspicuous behavior of the horse is a warning sign. An exact diagnosis can only be made by a vet.