Understanding the Vestibular System in Dogs
Dogs rely heavily on their vestibular system for balance control, and any malfunctioning within it can result in a myriad of issues such as eye twitching. In this section, we’ll delve into the crucial role of inner ear sensors and balance sensors for head position detection in the vestibular system. Additionally, we’ll examine the specialized control center in the brain that is responsible for converting head position information into electrical signals.
Role of Inner Ear Sensors in Balance Control
The inner ear sensors are very important for a dog’s balance. Located in the inner ear, the vestibular system sends signals to the brain about movement and position. Hair cells in the inner ear activate when they feel motion and gravity, creating electrical messages.
The brain then interprets these messages and changes the head and eye movements accordingly. As well as this, the inner ear’s special balance sensors quickly recognize any sudden movements, e.g. shaking or tilting of the head.
Therefore, the inner ear sensors are essential for a dog’s balance and overall well-being. They provide the necessary information to sense positioning and alert the dog if anything significant happens.
Specialized Control Center in the Brain
The vestibular system in dogs is complex. It helps with balance, orientation and coordination. This system has a unique control center in the brain. It receives signals from inner ear sensors that detect changes in head position and movement. These signals control eye, head and body movements to keep balance.
The control center also works with other sensory systems, such as body posture and eye position. This prevents postural imbalances during movement. Plus, the brainstem helps transfer information between the different components of the vestibular system. This allows accurate head and body movements.
This control center is amazing. It accurately maps spatial orientation. Even without visual cues, dogs can keep their direction. The control center also compensates for any imbalances due to conditions like nystagmus or blepharospasm. In the end, it helps dogs navigate their environment safely and efficiently.
Importance of Body and Eye Position in Balance Control
Maintaining balance control is vital for dogs. Posture and eye-position play a key role. Sensors in the inner ear transmit information to the brain about body and eye position, enabling the dog to stay stable while moving.
These sensors must be in good orientation, for accurate head position feedback and a correct motor response. Yet, if head or eye position is altered it can lead to impaired balance, and cause anxiety and stress.
Pet caretakers/veterinarians must thus monitor senior dogs’ posture and environment carefully. If ignored, this can have serious consequences, impacting the dogs’ health, happiness, and well-being.
To sum up, keeping a steady body and eye positioning is necessary for dogs, so they can have a healthy life. Caretakers/veterinarians must be aware of the potential problem area – often overlooked – to ensure seniors can have the best life possible.
Role of Balance Sensors in Head Position Detection
Balance sensors in dogs are essential for their balance and coordination. Inside their inner ear, the vestibular system houses these sensors. They detect head position changes and activate the brain’s balance control centers. Fluid-filled canals inside the ear also move, responding to the dog’s head movement. Hair cells convert this motion into electrical signals then send them to the brain.
Balance sensors also help dogs detect gravity’s direction. This assists them in equilibrium. The eyes’ position relative to the body is key too. It helps the dog orient itself. Dogs rely more on their vestibular system than their vision, allowing them to navigate even with weak vision.
As dogs age, monitoring is essential. If we notice any signs of discomfort or agitation-like eye twitching- it’s a sign their vestibular system needs medical attention. A vet should diagnose and recommend treatment quickly.
Maintaining a dog’s balance is complex- involving electrical signals, balance sensors, hair cells and the brain. Pet owners can help ensure their four-legged friends enjoy a healthy life by paying attention to their health and well-being.
Conversion of Head Position Information into Electrical Signals
The Vestibular System in dogs translates head position into electrical signals that the brain can understand. It utilizes various sensors to detect changes in motion, head and body position, and acceleration. The signals are sent to the brainstem’s vestibular nuclei. This is critical for maintaining balance and coordination.
It detects head position changes to help with eye movements. This helps keep visual stability during motion. The brain interprets these signals as electric impulses. It helps the dog understand where it is relative to its surroundings.
The semicircular canals sense positional movements of fluids within the inner ear. Hair cells convert this displacement info into neural impulses. This helps the dog distinguish movement directionality when nodding or tilting its head.
Humans get seasick due to an evolved sensitivity to motion. However, domesticated dogs lack this developed sensitivity. And, while dogs may wink, it’s not necessarily a flirtatious gesture. Blepharospasm can cause involuntary eye twitching.
Blepharospasm in Dogs
Blepharospasm in dogs is a common condition that can be concerning for pet owners. This section will delve into the definition and symptoms of blepharospasm, the potential causes of this condition, and the various treatment options available. We will also briefly touch upon how a veterinarian can diagnose blepharospasm in dogs.
Definition and Symptoms of Blepharospasm
Blepharospasm is a condition in dogs that causes involuntary twitching of the eyelids. It can happen once in a while or persistently and affect one or both eyes. Symptoms may include blinking too much, squinting, rubbing the eyes, and feeling discomfort around the eyes. For proper diagnosis, you need to go to a vet since the cause of blepharospasm can vary.
It can be caused by foreign particles or infections in the eye, allergies, corneal ulcers, anterior uveitis, blepharitis, pannus, keratoconjunctivitis sicca, distichiasis, and blastomycosis. Some dogs have muscle spasms in their face and neck, but when they happen often or are severe, it could mean an underlying medical issue like blepharospasm.
For example, a four-year-old Beagle had increased sensitivity to light and twitching around his eyes. A vet found out the cause was demodex mites and gave supportive care plus treatment for demodicosis.
If you notice any of the symptoms of blepharospasm in your dog, it’s important to get help from a vet. Don’t let your dog suffer from eye twitching when help is available.
Causes of Blepharospasm
Blepharospasm is a condition that causes involuntary contractions of the eyelids. This can be caused by many things, as Reference Data shows. For example, dogs can get it due to foreign particles or eye infections. Additionally, allergies, corneal ulcers, anterior uveitis, blepharitis, pannus, keratoconjunctivitis sicca, distichiasis, and blastomycosis can trigger it.
It’s important to consult with a veterinarian to diagnose Blepharospasm in dogs. They will prescribe treatments based on the cause of the condition. Additionally, they’ll consider other symptoms displayed by the dog.
For instance, Daisy, an older dog, developed eyelid spasms due to corneal ulceration from wildflower scratches. Her owner took her to the vet, who prescribed medication for infection control and pain relief. After two days, Daisy’s eye twitching stopped.
In summary, blepharospasm can be caused by many factors. It’s important to see a professional for an accurate diagnosis and treatment for affected dogs.
Foreign Particles and Eye Infection
Foreign particles and eye infections can bring about blepharospasm in pooches. This is a condition when eyelids twitch or blink uncontrollably, which can disrupt vision and cause pain. It can come from various sources, such as allergies, corneal ulcers, anterior uveitis, blepharitis, and pannus.
Sometimes, sand or debris can get into the eye and cause irritation. Eye infections are when viruses or bacteria invade the eye tissue, leading to conjunctivitis and keratitis if not treated. This can bring on inflammation, which may lead to blepharospasm as a way to protect the eye from more bother.
If your pup is having this issue, go to the vet. They will assess the eye for signs of pain, redness, discharge, or inflammation. Tests may include a ocular discharge culture, Schirmer tear test, intraocular pressure measurement, fluorescein stain test, blood work-up panel, and biopsy of any masses.
For instance, a dog was recently having repeated blinking because of foreign particles. After going to the vet, it was found that dust mites from playing fetch with tennis balls on concrete caused an inflamed cornea. Anti-inflammatory drops prescribed by the vet helped the pup’s health drastically, giving it more years to live.
It’s possible that eye allergies and corneal ulcers cause blepharospasm in dogs. With the right diagnosis and treatment, however, these issues can be resolved and the pup can live a happy life. If you notice any peculiar eye movement, go to the vet straight away.
Allergies and Corneal Ulcer
Dogs can experience blepharospasm due to various causes. Allergies, like those caused by dust mites and other irritants, can irritate and inflame their eyes. This can lead to them scratching or rubbing their face, causing corneal ulcers. These open sores on the cornea can lead to epiphora, or excessive tearing, as well as ocular discharge and twitching of the eyelids.
Bright light and foreign objects in the eye can worsen the pain and sensitivity of the cornea. If your dog displays signs of blepharospasm, see a vet right away for diagnosis and treatment. Medications, such as antibiotics and anti-inflammatories, may be prescribed, as well as desensitization shots over several months, if allergies are the cause.
Timely medical attention can also identify other underlying health issues, such as anterior uveitis, blepharitis, and pannus. Pay attention to any signs of discomfort or eye conditions your dog may have. Don’t let eye twitching go untreated – your pup deserves the best eye care available.
Anterior Uveitis, Blepharitis, and Pannus
Dogs can suffer from eye issues, such as anterior uveitis, blepharitis, and pannus. Anterior uveitis is a swelling of the iris. Blepharitis is an inflammation of the lid’s edge. Pannus is an abnormal tissue on the cornea’s outer layer. These issues can be caused by allergies, infections, or autoimmune diseases. Symptoms include redness, discharge, rubbing, or blinking too much.
If not treated, these can lead to vision loss or blindness. A vet can diagnose and treat them with the right care, based on how severe they are and what caused them. Foreign materials and infections can cause anterior uveitis and blepharitis. Allergens can bring on eye twitching in certain dog breeds. Other causes include distichiasis, keratoconjunctivitis sicca, or blastomycosis.
Treatment depends on its severity. Mild cases can be fixed with topical medication after cleaning the eyelids. For moderate cases, surgery may be needed if tests are needed. For more complex cases, anti-inflammatory drugs may help reduce inflammation during chronic infections.
Huskies may experience anterior uveitis/beginning pannus late in life due to possible genetic issues. Early detection and prevention can lessen the risks.
Keratoconjunctivitis Sicca, Distichiasis, and Blastomycosis
Keratoconjunctivitis Sicca, Distichiasis, and Blastomycosis can all be potential causes of blepharospasm in dogs. Dogs with Keratoconjunctivitis Sicca have eyes that don’t produce enough tears. Distichiasis causes abnormal growth of eyelashes, which can harm the cornea. Blastomycosis is a fungal infection that can lead to inflammation in eyes and other organs.
These conditions bring pain and discomfort to dogs, which often results in excessive blinking or spasms. Veterinarians can diagnose these conditions through Schirmer tear tests, corneal staining tests, blood tests, or tissue biopsies.
Treatment options vary. For Distichiasis, a vet surgeon removes the abnormally growing eyelashes through surgery. For other conditions, like Keratoconjunctivitis Sicca and Blastomycosis, medications like topical ointments or antibiotics may be necessary. If a dog shows signs of eye twitches or discharge, consult a veterinarian right away to prevent complications or sight loss.
It is important to remember that some breeds may be more vulnerable to certain eye-related issues. Doing a comprehensive check-up can help identify these issues early.
Lastly, one hopes that the vet doesn’t have blepharospasm while diagnosing a dog with these conditions.
Diagnosis of Blepharospasm by a Veterinarian
As pet owners, we all want our furry friends to be healthy and happy. But sometimes they experience conditions that need vet help. Blepharospasm is one such problem that causes a dog’s eye to blink or twitch uncontrollably. We must consult a vet to diagnose and treat it.
Vets are important for finding the cause of blepharospasm. They examine the dog’s eyes, checking vision, tear production, and inflammation. By watching the dog and doing tests, they can figure out what’s behind the twitching. Blood work and neurological exams may be done to look for allergies, ulcers, and infections.
To get a better understanding, they may use an ophthalmoscope to examine the eye. More severe cases may require MRI or CT scans if the nervous system is affected.
It’s essential to get professional help for eye-related issues like blepharospasm. Fortunately, treatments are available to help dogs. With the help of vets, we can stop the eye twitching and restore their health.
Treatment Options for Blepharospasm
Medical treatment for blepharospasm in dogs is based on the cause. A vet will diagnose and prescribe meds and therapies. This may include antibiotics, antivirals, anti-inflammatories, and eye drops. Surgery could be needed for severe cases or underlying conditions such as ulcers or entropion.
Owners can also reduce stress with music or calming scents. Warm compresses and massaging around the eyes can help relax muscles. Monitor behavior for side effects and report to the vet.
Regular check-ups are vital. A healthy diet and exercise routine can help prevent diseases that could cause twitching. A combination of meds and a comfortable environment is essential for managing blepharospasm.
Nystagmus as an Underlying Cause of Eye Twitching
Nystagmus can be one of the causes of eye twitching in older dogs, making it a crucial underlying factor to understand. This section will explore:
- The definition and causes of nystagmus.
- The different types of nystagmus, including peripheral and central vestibular diseases.
- Treatment options for peripheral vestibular disease
- The prognosis for central vestibular disease, as well as idiopathic and congenital vestibular diseases.
It is important to identify the underlying causes of eye twitching in older dogs.
Definition and Causes of Nystagmus
Nystagmus, an involuntary rhythmic eye movement, can be difficult for dogs to focus on. It can move horizontally, vertically, or rotary and the speed it moves at classifies it.
Reasons for nystagmus in dogs include ear infections, head traumas, poisoning, brain tumors, and vestibular disease. Vestibular disease is a common condition from damage or inflammation of the inner ear or brainstem. It causes imbalance and coordination issues, as well as nystagmus. Idiopathic and congenital vestibular diseases can cause nystagmus, particularly in elderly dogs.
Treatment for nystagmus depends on its cause. Medication may help in mild cases. For more severe cases of vestibular disease, therapy can help to control symptoms and rehabilitate coordination. Veterinary professionals need to diagnose the underlying condition to create an effective treatment plan, as nystagmus is usually accompanied by other signs like loss of balance or nausea.
Peripheral Vestibular Disease and Its Treatment
Peripheral vestibular disease is when damage or a dysfunction happens to the vestibular system in the inner ear. This leads to symptoms like nystagmus, head tilt, and imbalance. Treatment depends on the cause. Medication to manage nausea and vertigo can be used, plus physical therapy and environmental changes.
Supportive measures can help reduce symptoms and support recovery. Reduce stress and discomfort, provide a safe and stable environment, and encourage gentle activity to keep muscles toned. With proper management and treatment, many dogs can improve.
If owners think their dog has peripheral vestibular disease, it is important to get veterinary attention. A detailed examination of the ears, eyes, and neurological function can help identify causes or factors. This helps develop treatment that meets the needs of each dog.
Central Vestibular Disease and Its Prognosis
Central vestibular disease can have a huge effect on a pet’s health. Its prognosis depends on various factors. This involves impairment of the CNS, including the brain, spinal cord, cranial nerves, and cerebellum. It can cause a variety of vestibular symptoms that are tough to manage.
Several factors affect the prognosis, such as the cause of the condition, the severity of symptoms, the pet’s age, and their health status. Early diagnosis and treatment are crucial to improve outcomes, since treatment options vary depending on the cause.
Common causes of central vestibular disease include infectious diseases like meningitis or encephalitis, strokes, tumors, or trauma. If caused by a tumor or stroke, the prognosis may be poor, as the damage can be permanent. On the flip side, if caused by vet encephalitis or other neurological diseases, such as CDV, early detection and aggressive treatment can improve outcomes.
Pet owners can also help ensure the health of older dogs who may be vulnerable to vestibular disease. Regular check-ups with vets can help detect changes earlier and create long-term management plans. Pet owners can make sure their furry friends get the care they need to manage central vestibular disease and maintain their quality of life.
Idiopathic and Congenital Vestibular Diseases
Idiopathic and Congenital Vestibular Diseases can be challenging to treat as the underlying cause may remain unknown. However, some conditions such as severe head trauma or ototoxic drugs during gestation can cause vestibular diseases in a dog. It is important for a veterinarian to diagnose such diseases correctly. Tests such as CT scans, MRI studies, and blood workups will be conducted to determine the severity of the condition.
Treatment may involve supportive care with medication to control symptoms like nausea and dizziness.
Pro Tip: Take steps to ensure your dog’s quality of life is not significantly impacted by their idiopathic and congenital vestibular diseases.
Diagnosis and Treatment of Eye Twitching in Older Dogs
As our furry pals age, they may develop eye twitching among other health concerns. In this section, we delve into the diagnosis and treatment of eye twitching in older dogs. We will explore the importance of veterinary consultation, additional symptoms to note, identification of underlying causes, and medication prescription. Additionally, we will discuss comforting methods for reducing stress and agitation in our four-legged friends. Be sure to keep an eye out for potential side-effects of medications too.
Importance of Consulting a Veterinarian
Consulting a veterinarian is essential when it comes to addressing health issues in dogs. Especially older canines with eye twitching. Veterinary professionals have the necessary expertise to diagnose and treat ailments. Plus, they can provide guidance on how to give proper care to dogs with health concerns.
A veterinarian can evaluate the dog’s symptoms, medical history, and do tests to determine the cause of the eye twitching. Then, they can tailor treatments to the dog’s needs. This includes prescribing medication or suggesting lifestyle changes.
Regular check-ups with a trusted vet can maintain a dog’s health. It can also lead to early detection of health problems and preventive measures. Consulting a vet can lead to an accurate diagnosis and effective treatment of eye twitching and other health problems. So, it’s essential to consult a vet for dogs showing symptoms of eye twitching or any other health issues.
Noting Additional Symptoms for Accurate Diagnosis
Veterinarians are essential for making accurate diagnoses. Eye twitching in older dogs can be a sign of another issue. Other symptoms to note include head tilting, circling, loss of balance, and difficulty walking. These might be caused by vestibular disease or brain tumors. It’s important to check for infections or inflammation around the eye too.
A comprehensive medical history is key. Understanding the context and severity of an older dog’s health issues helps vets provide the right treatments quickly. It also reveals any pre-existing conditions that may be impacting the dog’s current health.
For example, my neighbor’s dog ‘Max’ had been twitching his eyes off-and-on for over a week. He went to the vet. They asked about his history and did some tests. Max had blepharitis from allergies to the changing weather. The vet gave him treatment and his twitching stopped. His health improved.
In summary, vets help older dogs by noting extra symptoms and getting a full medical history. This allows them to provide effective treatments and improve quality of life.
Identification of Underlying Causes and Prescription of Medication
Identifying underlying causes and prescribing medication are key to treat eye twitching in older dogs. Treating symptoms isn’t enough; the cause of the twitching must be addressed. To do so, the vet will examine the dog and review its medical history, plus run specific tests.
After determining the cause, the vet will give the right medication. This could be antibiotics, antihistamines, anti-inflammatory drugs, pain relievers, or even surgery. Each dog may react differently to the meds, depending on breed and age, and side effects like vomiting, diarrhea, or lethargy may occur.
Pet parents must monitor their pet after starting the medication and report any changes. Regular vet appointments should also be made for follow-up checks.
Comforting Methods for Reducing Stress and Agitation
For old dogs with eye twitching, wellbeing can be improved by using comforting methods that reduce stress and agitation. A low-stress environment is essential. Space, warmth and attention are important needs.
Calming techniques like massage, stroking and compresses can minimize stress. A healthier diet can help soothe nerves and reduce stress. Reducing sudden noises and movements will help with eye twitching. Prioritizing mental health is key. This includes easeful techniques, reducing external stimuli and addressing health concerns.
Pet insurance plans should prioritize care for old dogs with eye twitching. Regular checkups are beneficial.
Cassie, a nine-year-old chow chow mix, had severe eye twitching. Her owners provided a comfortable environment early on. Changing her diet also helped. This led to improvements.
Checking for Medication Side Effects
Administering meds to dogs? Check for side effects. These can be seen in various ways, and could harm your pet. For example, older dogs with eye twitching might have side effects like vomiting, diarrhea, or lethargy.
Therefore, observe your dog carefully after starting treatment. Look for unusual behavior. If you see significant changes or your pet looks ill, go to the vet right away. Meds may also change appetite or coat. So, pay attention to your pet during treatment.
It’s possible for side effects to take several days to show. So, be patient. Early detection can help prevent severe health issues later.
As an aging dog owner, be aware of your pet’s health. Vet check-ups, a calm environment, and good diet/exercise are important for caring for your pet with eye twitching.
Conclusion: Caring for Older Dogs with Eye Twitching
As we near the conclusion of our discussion on eye twitching in older dogs, it’s important to understand how we can care for our furry companions. This section focuses on some practical tips and guidelines to ensure that your older dog with eye twitching receives the best possible care. We’ll touch upon:
- Regular vet check-ups
- Creating a stress-free environment
- Maintaining a healthy diet and exercise routine
All of these factors contribute towards your dog’s overall well-being.
Regular Veterinary Check-ups for Early Detection of Health Problems
Veterinary check-ups should be done regularly for older dogs. This can help detect health issues early, such as eye twitches. The vet may assess the dog’s health during these appointments. Blood tests and other diagnostics may also be needed. Early detection of problems can help the dog’s quality of life and lifespan.
Owners should prioritize these check-ups. Also, watch the dog for changes in eating, energy, or behavior. With a good diet, exercise, and regular check-ups, the dog’s health can be monitored.
Providing a Comfortable and Low-stress Environment
Creating a comfy, low-stress environment is vital for older pup health and happiness. To achieve this, give them a calm, safe place to rest. Routine is key, so feed, exercise, and play with them on a regular schedule.
Provide a warm bed so they can sleep peacefully. Dim lighting and less noise can help keep them calm too. Social interaction is great for them, but make sure it’s not too overwhelming.
Pro Tip: Incorporate these practices into your pup’s daily routine. This will reduce anxiety and promote relaxation in their golden years.
Maintaining a Healthy and Balanced Diet and Exercise Routine.
For the well-being of older dogs, it is essential to maintain a healthy and balanced diet and exercise routine. Include ample protein, vitamins, and minerals in their diet. Exercise is also necessary, and should be tailored to their age, size, and physical condition. Adequate hydration is vital for proper organ function.
An improper diet or lack of exercise can cause various problems. These include eye twitching, hair loss, weight changes, lethargy, and digestive issues. It is important to follow a consistent diet plan and do appropriate exercises.
Besides a balanced diet and exercise, older dogs need sufficient sleep. This contributes to their better health and provides them with energy.
Research has found that dogs that exercise and maintain a healthy weight have fewer age-related diseases such as arthritis and heart disease. Adopting a healthy lifestyle can lead to a longer lifespan with fewer medical challenges.
FAQs about Eye Twitching In Older Dogs
What is blepharospasm and how does it affect dogs?
Blepharospasm refers to the involuntary blinking or twitching of a dog’s eyelid(s). It can affect one or both eyes in dogs and may occur due to a foreign particle on the eye’s surface or eye disease. Twitching and rapid blinking are signs of blepharospasm. A dog may also rub or scratch the eye, causing further inflammation and redness. Causes of blepharospasm include foreign particles, eye infection, allergies, corneal ulcer, anterior uveitis, blepharitis, pannus, keratoconjunctivitis sicca, distichiasis, blastomycosis, and various other eye issues. Diagnosing blepharospasm is often simple for a veterinarian to identify.
What is nystagmus and what are its causes?
Nystagmus is a rapid, involuntary movement of the eyes that can appear as bouncing or rapid movement without focus. It is a symptom of an underlying vestibular disease that disrupts nerve messages to the brain responsible for balance and spatial awareness. The causes of nystagmus include peripheral vestibular disease (involving inner and middle ear trauma or inflammation), central vestibular disease (affecting parts near the brain stem), idiopathic vestibular syndrome (age-related), or congenital vestibular disease (physical defect from birth). Peripheral vestibular disease is the most common and can usually be cleared up within a few weeks once the underlying cause is determined. Central vestibular disease is rare, but prognosis for recovery is poor due to brain damage.
What is the vestibular system and how does it control balance?
The vestibular system controls balance and prevents falling over. Sensors are located deep inside the ear in the inner ear. A specialized control center is located at the back of the brain. Tiny changes in body and eye positions are required for balance control. Balance sensors detect head position while standing or moving. Information on head position is converted into electrical signals and sent to the brain. The balance control center processes this information and sends messages to keep the animal upright. Messages are sent to muscles controlling eye movement to adjust to head position.
What are the signs of nystagmus in dogs and how is it treated?
The signs of nystagmus in dogs include a rapid, bouncing movement of the eyes without focus. Treatment for nystagmus depends on the underlying cause and may include medication, changes in diet or lifestyle, or surgery in severe cases. The dog’s veterinarian will be able to determine the appropriate treatment for the specific case of nystagmus.
What should I do if my older dog is experiencing eye twitches?
Eye twitching in older dogs can be a sign of various health problems and should be diagnosed by a veterinarian as soon as possible. Other symptoms like infection, fever, or lethargy should be noted to help with an accurate diagnosis. The vet will try to identify the underlying cause of the eye twitching and prescribe medication if necessary. Comforting the dog by petting and talking in a calming voice can help reduce stress and agitation. It is important to determine if the eye twitching is a side effect of other medications.
Who is Pippa Elliott MRCVS and what is her contribution to the article on eye twitching in dogs?
Pippa Elliott, MRCVS, is a veterinarian with over 30 years of experience who co-authored the article on eye twitching in dogs. Her expertise and knowledge of animal health helped to create a comprehensive guide for pet owners to better understand the various causes and treatments for eye twitches in dogs.