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Controversies exist around eliminating this disorder from breeding Collies. Some veterinarians advocate only breeding dogs with no evidence of disease, but this would eliminate a large portion of potential breeding stock. Because of this, others recommend only breeding mildly affected dogs, but this would never completely eradicate the condition. Also, mild cases of choroidal hypoplasia may become pigmented and therefore undiagnosable by the age of three to seven months. If puppies are not checked for CEA before this happens, they may be mistaken for normal and bred as such. Checking for CEA by seven weeks of age can eliminate this possibility. Diagnosis is also difficult in dogs with coats of dilute color because lack of pigment in the choroid of these animals can be confused with choroidal hypoplasia. Also, because of the lack of choroidal pigment, mild choroidal hypoplasia is difficult to see, and therefore cases of CEA may be missed.
Until recently, the only way to know if a dog was a carrier was for it to produce an affected puppy. However, a genetic test for CEA became available at the beginning of 2005, developed by the Baker Institute for Animal Health, Cornell University, and administered through OptiGen. The test can determine whether a dog is affected, a carrier, or clear, and is therefore a useful tool in determining a particular dog's suitability for breeding.
Vitrectomy is the common way to treat a macular hole. It is done by placing a gas bubble in the vitreous of the eye which helps flatten macular hole and holds it in place as the eye heals. The gas bubble slowly shrinks on its own. Treatment is also done using ocriplasmin.
Colobomas of the iris may be treated in a number of ways. A simple cosmetic solution is a specialized cosmetic contact lens with an artificial pupil aperture. Surgical repair of the iris defect is also possible. Surgeons can close the defect by stitching in some cases. More recently artificial iris prosthetic devices such as the Human Optics artificial iris have been used successfully by specialist surgeons. This device cannot be used if the natural lens is in place and is not suitable for children. Suture repair is a better option where the lens is still present.
Vision can be improved with glasses, contact lenses or even laser eye surgery but may be limited if the retina is affected or there is amblyopia.
Though there is no treatment for Cone dystrophy, certain supplements may help in delaying the progression of the disease.
The beta-carotenoids, lutein and zeaxanthin, have been evidenced to reduce the risk of developing age related macular degeneration (AMD), and may therefore provide similar benefits to Cone dystrophy sufferers.
Consuming omega-3 fatty acids (docosahexaenoic acid and eicosapentaenoic acid) has been correlated with a reduced progression of early AMD, and in conjunction with low glycemic index foods, with reduced progression of advanced AMD, and may therefore delay the progression of cone dystrophy.
It is known to occur in Scotch Collies (smooth and rough collies), Shetland Sheepdogs, Australian Shepherds, Border Collies, Lancashire Heelers, and Nova Scotia Duck Tolling Retrievers. Frequency is high in Collies and Shetland Sheepdogs, and low in Border Collies and NSDTRs. In the United States, incidence in the genotype of collies has been estimated to be as high as 95 percent, with a phenotypic incidence of 80 to 85 percent.
In the early stages, there are a few treatment options. Laser surgery or cryotherapy (freezing) can be used to destroy the abnormal blood vessels, thus halting progression of the disease. However, if the leaking blood vessels are clustered around the optic nerve, this treatment is not recommended as accidental damage to the nerve itself can result in permanent blindness. Although Coats' disease tends to progress to visual loss, it may stop progressing on its own, either temporarily or permanently. Cases have been documented in which the condition even reverses itself. However, once total retinal detachment occurs, sight loss is permanent in most cases. Removal of the eye (enucleation) is an option if pain or further complications arise.
Cell based therapies using bone marrow stem cells as well as retinal pigment epithelial transplantation are being studied. A number of trials have occurred in humans with encouraging results.
A practical application of AMD-associated genetic markers is in the prediction of progression of AMD from early stages of the disease to neovascularization.
The most extensive epidemiological survey on this congenital malformation has been carried out by Dharmasena et al and using English National Hospital Episode Statistics, they calculated the annual incidence of anophthalmia, microphthalmia and congenital malformations of orbit/lacrimal apparatus from 1999 to 2011. According to this study the annual incidence of congenital microphthalmia in the United Kingdom was 10.8 (8.2 to 13.5) in 1999 and 10.0 (7.6 to 12.4) in 2011.
The number of cases is around 0.5 to 0.7 per 10,000 births, making it a relatively rare condition.
CNV is conventionally treated with intravitreal injections of angiogenesis inhibitors (also known as "anti-VEGF" drugs) to control neovascularization and reduce the area of fluid below the retinal pigment epithelium. Angiogenesis inhibitors include pegaptanib, ranibizumab and bevacizumab (known by a variety of trade names, such as Macugen, Avastin or Lucentis). These inhibitors slow or stop the formation of new blood vessels (angiogenesis), typically by binding to or deactivating the transmission of vascular endothelial growth factor ('VEGF'), a signal protein produced by cells to stimulate formation of new blood vessels. The effectiveness of angiogenesis inhibitors has been shown to significantly improve visual prognosis with CNV, the recurrence rate for these neovascular areas remains high.
CNV may also be treated with photodynamic therapy coupled with a photosensitive drug such as verteporfin (Visudyne). The drug is given intravenously. It is then activated in the eye by a laser light. The drug destroys the new blood vessels, and prevents any new vessels forming by forming thrombi.
Therapy is not required or indicated in posterior vitreous detachment, unless there are associated retinal tears, which need to be repaired. In absence of retinal tears, the usual progress is that the vitreous humor will continue to age and liquefy and floaters will usually become less and less noticeable, and eventually most symptoms will completely disappear. Prompt examination of patients experiencing vitreous humor floaters combined with expeditious treatment of any retinal tears has been suggested as the most effective means of preventing certain types of retinal detachments.
Macular degeneration is a condition affecting the tissues lying under the retina, while a macular hole involves damage from within the eye, at the junction between the vitreous and the retina itself. There is no relationship between the two diseases. Depending upon the degree of attachment or traction between the vitreous and the retina, there may be risk of developing a macular hole in the other eye. In those cases where the vitreous has already become separated from the retinal surface, there is very little chance of developing a macular hole in the other eye. On the other hand, when the vitreous remains adherent and pulling on the macular region in both eyes, then there may be a greater risk of developing a hole in the second eye. In very rare instances, trauma or other conditions lead to the development of a macular hole. In the vast majority of cases, however, macular holes develop spontaneously. As a result, there is no known way to prevent their development through any nutritional or chemical means, nor is there any way to know who is at risk for developing a hole prior to its appearance in one or both eyes.
It is extremely important to see an ophthalmologist regularly. Research indicates that supplements slow the disease and lessen the symptoms. Supplements such as Vitamin A, lutein, omega-3 fatty acid DHA have shown to help this disease. While supplements may help lessen the symptoms, retinitis itself is not curable. Additionally, devices such as low-vision magnifiers can be used to aid vision in patients suffering from despaired vision due to retinitis. Rehabilitation services may also aid the patient so that patients may use their vision in a more effective manner. Lastly, it is advisable to wear sunglasses even on gloomy days to protect your eyes from any ultraviolet light.
Current research on Retinitis includes studying stem cells, medications, gene therapies, and transplants to help treat/cure this condition. A study including patients with Retinitis was conducted by using gene therapy. Results from this study indicated that patients experienced some restored vision. Such studies indicate that the future may allow treatment of Retinitis by inserting healthy genes in the retina to cure this disease.
Chorioretinitis is usually treated with a combination of corticosteroids and antibiotics. However, if there is an underlying cause such as HIV, specific therapy can be started as well.
A 2012 Cochrane Review found weak evidence suggesting that ivermectin could result in reduced chorioretinal lesions in patients with onchocercal eye disease. More research is needed to support this finding.
Careful eye examination by an ophthalmologist or optometrist is critical for diagnosing symptomatic VMA. Imaging technologies such as optical coherence tomography (OCT) have significantly improved the accuracy of diagnosing symptomatic VMA.
A new FDA approved drug was released on the market late 2013. Jetrea (Brand name) or Ocriplasmin (Generic name) is the first drug of its kind used to treat vitreomacular adhension.
Mechanism of Action: Ocriplasmin is a truncated human plasmin with proteolytic activity against protein components of the vitreous body and vitreretinal interface. It dissolves the protein matrix responsible for the vitreomacular adhesion.
Adverse drug reactions: Decreased vision, potential for lens sublaxation, dyschromatopsia (yellow vision), eye pain, floaters, blurred vision.
New Drug comparison Rating gave Jetea a 5 indicating an important advance.
Previously, no recommended treatment was available for the patient with mild symptomatic VMA. In symptomatic VMA patients with more significant vision loss, the standard of care is pars plana vitrectomy (PPV), which involves surgically removing the vitreous from the eye, thereby surgically releasing the symptomatic VMA. In other words, vitrectomy induces PVD to release the traction/adhesion on the retina. An estimated 850,000 vitrectomy procedures are performed globally on an annual basis with 250,000 in the United States alone.
A standard PPV procedure can lead to serious complications including small-gauge PPV. Complications can include retinal detachment, retinal tears, endophthalmitis, and postoperative cataract formation. Additionally, PPV may result in incomplete separation, and it may potentially leave a nidus for vasoactive and vasoproliferative substances, or it may induce development of fibrovascular membranes. As with any invasive surgical procedure, PPV introduces trauma to the vitreous and surrounding tissue.
There are data showing that nonsurgical induction of PVD using ocriplasmin (a recombinant protease with activity against fibronectin and laminin) can offer the benefits of successful PVD while eliminating the risks associated with a surgical procedure, i.e. vitrectomy. Pharmacologic vitreolysis is an improvement over invasive surgery as it induces complete separation, creates a more physiologic state of the vitreomacular interface, prevents the development of fibrovascular membranes, is less traumatic to the vitreous, and is potentially prophylactic. As of 2012, ThromboGenics is still developing the ocriplasmin biological agent. Ocriplasmin is approved recently under the name Jetrea for use in the United States by the FDA.view.
An experimental test of injections of perfluoropropane (CF) on 15 symptomatic eyes of 14 patients showed that vitreomacular traction resolved in 6 eyes within 1 month and resolved in 3 more eyes within 6 months.
A cone dystrophy is an inherited ocular disorder characterized by the loss of cone cells, the photoreceptors responsible for both central and color vision.
In 2005, steroids were investigated for the treatment of macular edema due to retinal blood vessel blockage such as CRVO and BRVO.
Macular edema sometimes occurs for a few days or weeks after cataract surgery, but most such cases can be successfully treated with NSAID or cortisone eye drops. Prophylactic use of Nonsteroidal anti-inflammatory drugs has been reported to reduce the risk of macular edema to some extent.
In 2010 the US FDA approved the use of Lucentis intravitreal injections for macular edema.
Iluvien, a sustained release intravitreal implant developed by Alimera Sciences, has been approved in Austria, Portugal and the U.K. for the treatment of vision impairment associated with chronic diabetic macular edema (DME) considered insufficiently responsive to available therapies. Additional EU country approvals are anticipated.
In 2013 Lucentis by intravitreal injection was approved by the National Institute for Health and Care Excellence in the UK for the treatment of macular edema caused by diabetes and/or retinal vein occlusion.
On July 29, 2014, Eylea (aflibercept), an intravitreal injection produced by Regeneron Pharmaceuticals Inc., was approved to treat DME in the United States.
Photophobia may also affect patients' socioeconomic status by limiting their career choices, since many workplaces require bright lights for safety or to accommodate the work being done. Sufferers may be shut out of a wide range of both skilled and unskilled jobs, such as in warehouses, offices, workshops, classrooms, supermarkets and storage spaces. Some photophobes are only able to work night shifts, which reduces their prospects for finding work.
The best treatment for light sensitivity is to address the underlying cause. Once the triggering factor is treated, photophobia disappears in many but not all cases.
People with photophobia will avert their eyes from direct light, such as sunlight and room lights. They may seek the shelter of a dark room. They may wear sunglasses designed to filter peripheral light and wide-brimmed sun hats.
Wearing sunglasses indoors can make symptoms worse over time as it will dark-adapt the retina which aggravates sensitivity to light. Indoor photophobia symptoms may be relieved with the use of precision tinted lenses which block the green-to-blue end of the light spectrum without blurring or impeding vision.
A paper by Stringham and Hammond, published in the "Journal of Food Science", reviews studies of effects of consuming Lutein and Zeaxanthin on visual performance, and notes a decrease in sensitivity to glare.
Distortion of vision refers to straight lines not appearing straight, but instead bent, crooked, or wavy. Usually this is caused by distortion of the retina itself. This distortion can herald a loss of vision in macular degeneration, so anyone with distorted vision should seek medical attention by an ophthalmologist promptly. Other conditions leading to swelling of the retina can cause this distortion, such as macular edema and central serous chorioretinopathy.
An Amsler grid can be supplied by an ophthalmologist so that the vision can be monitored for distortion in people who may be predisposed to this problem.
Tunnel vision implies that the peripheral vision, or side vision, is lost, while the central vision remains. Thus, the vision is like looking through a tunnel, or through a paper towel roll. Some disorders that can cause this include:
Glaucoma - severe glaucoma can result in loss of nearly all of the peripheral vision, with a small island of central vision remaining. Sometimes even this island of vision can be lost as well.
Retinitis pigmentosa - This is usually a hereditary disorder which can be part of numerous syndromes. It is more common in males. The peripheral retina develops pigmentary deposits, and the peripheral vision gradually becomes worse and worse. The central vision can be affected eventually as well. People with this problem may have trouble getting around in the dark. Cataract can be a complication as well. There is no known treatment for this disorder, and supplements of Vitamin A have not been proven to help.
Punctate Inner Choroidopathy - This condition is where vessels gro (( material is missing ))
Stroke - a stroke involving both sides of the visual part of the brain may wipe out nearly all of the peripheral vision. Fortunately, this is a very rare occurrence
Gene therapy is currently not a treatment option, however human clinical trials for both choroideremia and Leber's congenital amaurosis (LCA) have produced somewhat promising results.
Clinical trials of gene therapy for patients with LCA began in 2008 at three different sites. In general, these studies found the therapy to be safe, somewhat effective, and promising as a future treatment for similar retinal diseases.
In 2011, the first gene therapy treatment for choroideremia was administered. The surgery was performed by Robert MacLaren, Professor of Ophthalmology at the University of Oxford and leader of the Clinical Ophthalmology Research Group at the Nuffield Laboratory of Ophthalmology (NLO).
In the study, 2 doses of the AAV.REP1 vector were injected subretinally in 12 patients with choroideremia.
There study had 2 objectives:
- to assess the safety and tolerability of the AAV.REP1 vector
- to observe the therapeutic benefit, or slowing of the retinal degeneration, of the gene therapy during the study and at a 24-month post-treatment time point
Despite retinal detachment caused by the injection, the study observed initial improved rod and cone function, warranting further study.
In 2016, researchers were optimistic that the positive results of 32 choroideremia patients treated over four and a half years with gene therapy in four countries could be long-lasting.
While choroideremia is an ideal candidate for gene therapy there are other potential therapies that could restore vision after it has been lost later in life. Foremost of these is stem cell therapy. A clinical trial published in 2014 found that a subretinal injection of human embryonic stem cells in patients with age-related macular degeneration and Stargardt disease was safe and improved vision in most patients. Out of 18 patients, vision improved in 10, improved or remained the same in 7, and decreased in 1 patient, while no improvement was seen in the untreated eyes. The study found "no evidence of adverse proliferation, rejection, or serious ocular or systemic safety issues related to the transplanted tissue." A 2015 study used CRISPR/Cas9 to repair mutations in patient-derived induced pluripotent stem cells that cause X-linked retinitis pigmentosa. This study suggests that a patient's own repaired cells could be used for therapy, reducing the risk of immune rejection and ethical issues that come with the use of embryonic stem cells.