Ophthalmology

Below, please find links to all of the clinical trials involving ophthalmology. The studies include a multitude of information, including (but not limited to) the study’s purpose, benefits for participating, and financial incentive information. If you have any questions, please contact the individual outlined at the end of each trial summary.

Please visit the Ophthalmology service webpage at the Veterinary Medical Teaching Hospital (VMTH) if you would like to learn more about the amazing things that our veterinarians can do for you and your animal.

Horses & Ponies

Equine Recurrent Uveitis: Assessing a Stem Cell Therapy

Title: Efficacy of Autologous Mesenchymal Stem Cells for Treatment of Equine Recurrent Uveitis Following Intravenous Injection

Purpose: Equine recurrent uveitis (ERU) is caused by inflammation of the uveal tract of the eye and is the most common cause of blindness in horses. ERU often involves lifelong medical therapy or surgery, which holds the potential for a variety of potentially serious complications. Because fat-derived stem cells are known to regulate inflammation and facilitate tissue repair, we wish to investigate the effectiveness of a new stem cell therapy for ERU and to better understand how stem cells work to limit inflammation. This treatment has the potential for being relatively non-invasive and removing the need for lifelong treatment.

Participation Requirements: Horses who have had multiple episodes of anterior uveitis within the last 12-18 months. The MSCs will be injected intravenously either during a period of inflammation or during a quiescent period.

Initial Evaluation for Participation: Horses that are candidates for inclusion into the study will be examined by a board certified veterinary ophthalmologist. This examination will determine if the horse has evidence of current or past uveitis.

Procedures: The trial procedures include the following:

  • Your horse will be sedated using common sedatives for each treatment. Local anesthetic will be used to provide optimal pain management for fat removal in addition to sedation.
  • A small amount of fat from an area near the tail of your horse will be removed in order to isolate and culture the MSCs. Your horse will be admitted for fat removal and monitored prior to its discharge home (likely the same day).
  • Two weeks after fat harvest, your horse will receive its first course of therapy, which involves an intravenous infusion of 50 million MSCs.
  • Two weeks after the first MSC treatment, your horse will receive a second injection of 100 million MSCs. At this time, your horse will be clinically examined and about 2/3 of a cup (60 mL) of blood will be collected.
  • Two weeks after the second round of injections, we will need to see examine your horse again. At this time, your horse will be clinically examined and about 1 tablespoon (10mL) of blood will be collected.

Benefits: The study will pay for costs associated with the ophthalmic examinations and interpretation, fat harvest and MSC expansion, and consecutive visits and therapy will be paid by the study. You (the owner) are responsible for treatments associated with any side effects incurred by your horse’s participation in the study.

We cannot promise any benefits to your horse or other animals from your taking part in this clinical trial; however, possible benefits include the potential of your horse achieving a state of remission without the use of long-term cyclosporine therapy Moreover, this study may help us to further target specific use of MSCs for other horses that suffer from ERU.

Owner Responsibilities: You will be required to bring your horse to the VMTH once for fat collection and twice for stem cell therapy. The ten horses comprising this study are client owned and will be returned to their owners two weeks after the 2nd injection. The animals will be examined every three months for up to 18 months following the study.

Contact: Dr. Steve Hollingsworth at srhollingsworth@ucdavis.edu

Cats

Dry Eye Syndrome (Keratoconjunctivitis sicca) or other tear film disorders: Understanding the Eye

Title: Ocular surface and tear film assessment in healthy cats and dogs

Purpose of Study: This study will examine new and current methods of assessing the tear film in normal cats.

Participation Requirements:

  • Healthy cats
  • Cats with evidence of a tear film dysfunction

Initial Evaluation for Participation: The initial examination will occur at your cat's regular ophthalmic appointment.

Procedures:

  • Schirmer tear test
  • Phenol red thread test
  • Conjunctival impression cytology
  • Tear osmometry
  • Meibometry
  • Tearfilm break up time

Benefits: There are no direct benefits for enrolling your cat in this study; however, we hope that the data acquired in this study will allow us to understand the tear film in our veterinary patients.

Owner Responsibilities: The owner is only required to bring their cat in and sign the owner informed consent document.

Contact: Lionel Sebbag (sebbaglionel@gmail.com)

Dogs

Corneal Endothelial Dystrophy: Understanding the Disease in Boston Terriers

Title: Phenotype and Genotype of Corneal Endothelial Dystrophy in Boston Terriers

Purpose of Study: Corneal endothelial dystrophy (CED) is a devastating disease in dogs that can result in blindness and severe ocular pain from secondary complications. The endothelial cells comprise the most inner aspect of the cornea and are responsible for maintaining a proper fluid balance. This function is critical to ensuring that the cornea remains transparent for vision. In many animals, including dogs, corneal endothelial cells have a very limited capacity to regenerate following injury. In canine patients with CED, the endothelial cells degenerate until the cells still remaining can no longer function properly. This results in swelling of the cornea (edema) which results in decreased vision as well as formation of small fluid-filled blisters (bullae) on the cornea which can rupture and cause ocular discomfort. There are palliative treatments such as hypertonic saline to decrease corneal bullae formation but the only definitive treatment for this condition is a corneal transplant (penetrating keratoplasty). Unfortunately, corneal transplants are rarely performed in canine patients with CED due to the expense of the surgery and follow-up care, relatively high risk of complications, and lack of appropriate donor tissue.

Several dog breeds, including Boston Terriers, are seen more commonly for CED in comparison to other breeds. This observation suggests that this disease may have a genetic component. A similar condition called Fuch’s endothelial corneal dystrophy (FECD) exists in humans and several genes associated with FECD have been identified. We propose to identify the region of the dog genome associated with CED in the Boston Terrier. In order to do this, we will perform thorough eye examinations and use non-invasive advanced imaging techniques to examine Boston Terriers with CED and age-matched control dogs. We will collect blood from these dogs to obtain DNA. The entire canine genome will be evaluated for an association with CED. This work will be used to identify the gene(s) responsible for this condition in Boston Terriers. The ultimate goal will be to develop a genetic test for CED in Boston Terriers and possibly other breeds, such as Chihuahuas, Dachshunds, and German Short Haired Pointers with an increased risk of CED.

Participation Requirements:

  • Boston Terriers with Corneal Endothelial Dystrophy
  • Healthy Boston Terriers (>7 years of age)

Initial Evaluation for Participation: Dogs must receive a diagnosis by a veterinary ophthalmologist for corneal endothelial dystrophy.

Procedures:

  • Ophthalmic examination
  • Noninvasive advanced corneal imaging with confocal microscopy and spectral domain-optical coherence tomography

NOTE: Sedation is required for these procedures.

Benefits: Benefits include an ophthalmic examination at no cost with thorough characterization of disease to aid in monitoring for progression.

Owner Responsibilities: No ophthalmic medications can be administered 48 h prior to examination. Food cannot be given in the morning in preparation for sedation.

Contact: Dr. Sara Thomasy (smthomasy@ucdavis.edu or (530) 752-1770)

Printable Flyer (PDF)

Corneal Endothelial Dystrophy: Understanding the Disease in German Shorthaired Pointers

Title: Phenotype and Genotype of Corneal Endothelial Dystrophy in German Shorthaired Pointers

Purpose of Study: Corneal endothelial dystrophy (CED) is a devastating disease in dogs that can result in blindness and severe ocular pain from secondary complications. The endothelial cells comprise the most inner aspect of the cornea and are responsible for maintaining a proper fluid balance. This function is critical to ensuring that the cornea remains transparent for vision. In many animals, including dogs, corneal endothelial cells have a very limited capacity to regenerate following injury. In canine patients with CED, the endothelial cells degenerate until the cells still remaining can no longer function properly. This results in swelling of the cornea (edema) which results in decreased vision as well as formation of small fluid-filled blisters (bullae) on the cornea which can rupture and cause ocular discomfort. There are palliative treatments such as hypertonic saline to decrease corneal bullae formation but the only definitive treatment for this condition is a corneal transplant (penetrating keratoplasty). Unfortunately, corneal transplants are rarely performed in canine patients with CED due to the expense of the surgery and follow-up care, relatively high risk of complications, and lack of appropriate donor tissue.

Several dog breeds, including German Shorthaired Pointers, are seen more commonly for CED in comparison to other breeds. This observation suggests that this disease may have a genetic component. A similar condition called Fuch’s endothelial corneal dystrophy (FECD) exists in humans and several genes associated with FECD have been identified. We propose to identify the region of the dog genome associated with CED in the German Shorthaired Pointer. In order to do this, we will perform thorough eye examinations and use non-invasive advanced imaging techniques to examine German Shorthaired Pointers with CED and age-matched control dogs. We will collect blood from these dogs to obtain DNA. The entire canine genome will be evaluated for an association with CED. This work will be used to identify the gene(s) responsible for this condition in German Shorthaired Pointers. The ultimate goal will be to develop a genetic test for CED in German Shorthaired Pointers and possibly other breeds, such as Chihuahuas, Dachshunds, and Boston Terriers with an increased risk of CED.

Participation Requirements:

  • German Shorthaired Pointers with Corneal Endothelial Dystrophy
  • Healthy German Shorthaired Pointers (>7 years of age)

Initial Evaluation for Participation: Dogs must receive a diagnosis by a veterinary ophthalmologist for corneal endothelial dystrophy.

Procedures:

  • Ophthalmic examination
  • Noninvasive advanced corneal imaging with confocal microscopy and spectral domain-optical coherence tomography

NOTE: Sedation is required for these procedures.

Benefits: Benefits include an ophthalmic examination at no cost with thorough characterization of disease to aid in monitoring for progression.

Owner Responsibilities: No ophthalmic medications can be administered 48 h prior to examination. Food cannot be given in the morning in preparation for sedation.

Contact: Dr. Sara Thomasy (smthomasy@ucdavis.edu or (530) 752-1770)

Printable Flyer (PDF)

Dry Eye Syndrome (Keratoconjunctivitis sicca): Using Stem Cells as a Treatment

Title: Mesenchymal Stem Cell Therapy for the Treatment of Dry Eye in Dogs

Purpose of Study: Dry eye (keratoconjunctivitis sicca) is a common ocular disease in dogs that leads to discomfort and vision loss.  Mesenchymal stem cells (MSCs) have been proven to reduce inflammation and differentiate into a variety of cell types. Since the most common cause of dry eye in dogs is an immune-mediated inflammatory response targeted against tear producing glands, this study was designed to determine if treatment with MSCs will cause local, long term control of tear gland inflammation and dry eye.

Participation Requirements: Candidates for this clinical trial are those dogs who have confirmed dry eye with a starting Schirmer tear test level between 2-10 mm/min and whose tear production is currently well controlled on tear-stimulating medication (cyclosporine or tacrolimus).  Patients should be free of serious systemic disease. 

Initial Evaluation for Participation: Dogs must be evaluated at the VMTH and confirmed to have dry eye. In order to confirm dry eye, the tear-stimulating medication currently being used will be temporarily discontinued. Re-evaluation will occur weekly until it is determined that tear production levels drop accordingly. Once confirmed, therapy with tacrolimus or cyclosporine will be re-instituted.

Procedures: Serial Schirmer tear tests will be performed. This is a minimally invasive procedure to measure tear production. Patients undergo a minor surgical procedure during which a small sample of fat is obtained from the abdomen in order to harvest the stem cells. Under a separate sedation, these stem cells are injected into the lacrimal and third eyelid glands.

Benefits: There is no cost to the owner (examinations, ophthalmic medications and study procedures) while the patient is enrolled in the study. If the stem cell injection is successful, we will treat the other eye with stem cells at no cost to the owner. 

If MSCs injected into the tear producing glands of dogs with immune-mediated dry eye results in increased tear production, this procedure may remove the need for life long topical supplemental therapies.

Owner Responsibilities: Owners are required to bring their dog in at the requested re-evaluations, which may be weekly prior to and immediately after the stem cell injection(s). Re-examination intervals will be extended based on response to therapy.

Contact: Monica Motta (mjmotta@ucdavis.edu or 530-752-0926)

Printable Flyer

Dry Eye Syndrome (Keratoconjunctivitis sicca): Understanding the Genetics in West Highland White Terriers

Title: The Genetics of Keratoconjunctivitis Sicca in West Highland White Terriers

Purpose of Study: Keratoconjunctivitis sicca (KCS) or dry eye is a devastating disease that causes ocular pain and potentially blindness. It is seen more frequently in West Highland White Terriers in comparison to many other breeds. We are interested identifying the genetic components of this disease as well as characterizing this disease better with examination and testing of the tear film and ocular surface and in select patients using advanced imaging techniques.

Participation Requirements:

  • West Highland White Terriers with Dry Eye Syndrome (affected); or,
  • West Highland White Terriers >7 years of age with no ocular abnormalities (control)

Initial Evaluation for Participation: Affected patients must receive a diagnosis by a veterinary ophthalmologist for dry eye. Dogs without ocular disease (controls) require no prior initial examination.

Procedures:

  • Routine ophthalmic examination and tear film tests
  • Blood collection for DNA analysis
  • Tears will be collected from the conjunctival sac using a blunt-tip needle attached to a syringe from both eyes. Tear collection will be performed at a separate time from the initial ophthalmic examination and tests.
  • Conjunctival biopsy – Two (2) minutes after regional anesthesia is applied, a small (approximately 5 mm x 2 mm) piece of conjunctiva will be removed from inside the lower eyelid.
  • Select patients only:
    • Advanced imaging: Spectral domain optical coherence tomography (non-contact imaging) and confocal biomicroscopy (imaging in which a gel on the instrument contacts the cornea) will also be performed to carefully image the cornea along with digital slit lamp photography.
    • Sedation for advanced imaging: In order to keep dogs relaxed and comfortable but awake for the advanced imaging, your dog will be given a mild sedative. The sedation chosen for your pet will depend on your dog’s age and health status.

Benefits: There will be no cost to you for your participation in this study and your dog will receive a very thorough eye examination at no charge. Results from this study will allow us to better predict the onset and progression of this disease. If a gene that causes this disease is found, then we may be able to develop a genetic test to know which dogs have or do not have this disease.

Owner Responsibilities: Although there is no cost to participate in the study, you will need to cover any costs due to complications from sedation, blood sampling, or examination (including corneal ulceration). Additionally, please do not administer any medications to treat your dog’s dry eye for two weeks prior to the appointment other than the lubricant provided to you. If your dog is participating in the advanced imaging, please do not feed your dog the morning of the appointment (water is fine), as the sedation administered can cause vomiting.

Contact: Dr. Sara Thomasy (smthomasy@ucdavis.edu or (530) 752-1770)

Printable Flyer (PDF)

Glaucoma: Understanding the Disease

Title: Understanding Glaucoma in Dogs through Evaluation of the Trabecular Meshwork

Purpose of Study: Glaucoma exists in many forms, but the basic fundamentals of the disease are simple. Fluid goes into the eye and cannot drain out at the same rate it is produced. This causes an increase in intraocular pressure. The increase in pressure affects other functions in the eye (especially retinal function) and can cause blindness as well as pain. Our lab recently demonstrated that the biophysical properties of the trabecular meshwork (the primary drainage pathway from the eye) are markedly altered in human eyes with glaucoma. It is of great interest to us to determine if there is a similar relationship in dogs with glaucoma.

Participation Requirements: Dogs that have been diagnosed with glaucoma and are scheduled to have a routine enucleation (removal of the eye) at the Veterinary Medical Teaching Hospital (VMTH).

Initial Evaluation for Participation: Confirmed diagnosis of Primary Glaucoma

Procedures: At the time the eye is removed from the patient but before it is placed in a fixative, the eye will be evaluated and a small tissue section will be obtained from the drainage angle of the eye for tissue analysis. The sample collected will consist of a 3-5 mm section of the iridocorneal angle (including cornea and sclera) that contains the primary outflow pathway for fluid from the eye (the trabecular meshwork). Immediately following resection of this sample, the eye will be placed in fixative and submitted for histological evaluation as planned.

Benefits: Analysis of the sample will allow us to evaluate the drainage pathway of a blind painful eye with glaucoma and will greatly contribute to our understanding of glaucoma in dogs. It may also point to new treatment options for this common, blinding and painful disease in dogs. The cost of the histo-pathological exam of the enucleated globe will be paid for by the study (saving the client approx. $70).

Owner Responsibilities: The client’s bill will be reduced by the cost of the histo-pathologic evaluation.

Contact: Monica Motta (mjmotta@ucdavis.edu or 530-752-0926)

Glaucoma: Examining Instrumentation for Diagnostic Capabilities

Title: Evaluation of Ocular Imaging Instrumentation for use in Vision Sciences

Purpose of Study: The purpose of this study is to evaluate ophthalmic imaging equipment and determine if the equipment can provide greater diagnostic capabilities and improve overall animal care and diagnostics.

Participation Requirements: Dogs that have been diagnosed with primary glaucoma and are scheduled to have a routine enucleation (removal of the eye) at the Veterinary Medical Teaching Hospital (VMTH).

Initial Evaluation for Participation: A complete ophthalmic exam.

Procedures: If an ocular contact instrument (Confocal, Pachymeter, A-Scan or Osmometer) is used for examination, a fluorescein stain will be done following the procedure to ensure an ulcer was not created. Sedation and/or anesthesia will be evaluated only if your dog is already undergoing sedation and/or anesthesia for routine care. Anesthetic time may be minimally (if at all) increased to complete the imaging examination.

Benefits: A better understanding of the use of ocular imaging instrumentation in various species will help provide a greater understanding of the diagnostic capability in those species and aid in improving patient care and diagnostics overall. Equipment that would provide a highly advanced diagnosis has the potential to minimize advancement in ocular disease/discomfort and detect severe or chronic conditions prior to severe complications.

Owner Responsibilities: Cost of additional imaging (Digital SL, OCT, Fundic, Confocal, Pachymetry, Osmometry or A-Scan U/S) beyond standard examination requirements will be covered by the study; however, the owner will be responsible for fees associated with the initial/examination visit and all sedation and/or anesthetic charges.

Contact: Monica Motta (mjmotta@ucdavis.edu or 530-752-0926)

Inherited Myopia (Near-sightedness): Understanding the Disease in Labrador Retrievers

Title: Genetic Investigation of Inherited Myopia in the Labrador Retriever

Purpose of Study: Myopia, or near-sightedness, is an inherited condition in the Labrador retriever, affecting about 15% of the breed. We propose to identify the region of the dog genome associated with myopia in the Labrador retriever. In order to do this, we will collect DNA samples (blood), pedigree data and quantitative non-invasive measurements of the refractive index. The entire genome will be evaluated for an association with myopia.

Participation Requirements: Dogs with Inherited Myopia

Initial Evaluation for Participation: Any purebred Labrador Retriever is welcome to participate.

Procedures:

  • Collection of all pedigree information related to your pet and its breed
  • A full ophthalmic health exam, refraction and CERF exam, during which your dog will be restrained by trained personnel
  • Collection of a small blood sample for DNA testing, which may require hair to be shaved so we can access a vein
  • A routine, non-invasive amplitude modulation scan (A-scan) to determine the length of your dog’s ocular globe and if there are any flaws

Benefits: There is no charge for you to allow your dog to participate in this clinical trial. All costs associated with the study will be paid by the sponsor/department.

We cannot promise any benefits to your dog or other animals from your taking part in this clinical trial; however, possible benefits include a free CERF examination by a board certified veterinary ophthalmologist. There will be no direct medical benefit to your dog; however, there will be a novel benefit to science and the discovery of inherited myopia in Labrador retrievers.

Owner Responsibilities: If you allow your dog to participate in this study, you will be responsible for bringing your dog in to the Veterinary Medical Teaching Hospital for testing on the scheduled date you are provided (NOTE: Your dog’s participation will not to exceed six (6) hours).

Contact: Miriam Aguilar (miraguilar@ucdavis.edu) to arrange to be contacted when we have a screening clinic.