OFA eye testing is a screening program for inherited eye diseases like Progressive Retinal Atrophy (PRA) in Dachshunds. The exam is part of the Companion Animal Eye Registry (CAER), which is administered by the Orthopedic Foundation for Animals (OFA) in conjunction with the American College of Veterinary Ophthalmologists (ACVO). 
The OFA eye exam process

• Performed by specialists. The exam must be performed by a board-certified veterinary ophthalmologist (a Diplomate of the ACVO).
• Dilation is required. The dog's pupils are dilated with special drops about 30 to 40 minutes before the examination.
• In-depth screening. The ophthalmologist performs a screening using indirect ophthalmoscopy and slit lamp biomicroscopy to examine the eyelids, cornea, lens, retina, and optic nerve.
• Certification length. A passing certification is valid for 12 months, and annual re-examinations are recommended for breeding dogs.
• Public database. Passing results and breeder-option conditions are published in the OFA's public database. Owners may also opt to submit non-passing results. 

Progressive Retinal Atrophy (PRA) in Dachshunds
PRA is a group of inherited degenerative diseases of the retina that lead to progressive, non-painful vision loss and eventual blindness. 

• Symptoms: Early signs often include night blindness, followed by vision loss in normal daylight. Owners may notice their dog becoming hesitant to go down stairs or entering dark rooms, bumping into things, and having abnormally dilated pupils.
• Genetic component: Several genetic variants can cause PRA, and the age of onset varies depending on the specific mutation. Some types appear in young dogs, while others don't cause symptoms until middle or later ages.
• Varieties affected: Specific types of PRA have been identified in Miniature Long Haired and other Dachshund varieties.
• No cure. There is no cure for PRA, but most dogs adapt well to their gradual vision loss. Treatments focus on helping the dog cope with their reduced vision.
• DNA testing. Genetic DNA tests are available to identify carriers of known PRA variants. This allows breeders to make informed decisions to reduce the incidence of the disease in their puppies. 

Why both tests are important for breeders
Responsible Dachshund breeders use both types of tests to ensure the health of their dogs and puppies.

• OFA eye exam (phenotype): This annual clinical exam by an ophthalmologist checks for the observable signs of inherited eye diseases at that moment in time. It helps track conditions that may develop later in life.
• DNA testing for PRA (genotype): This one-time genetic test identifies whether a dog is a carrier for known PRA gene mutations. Because PRA is an autosomal recessive disorder, a dog can be a carrier of the gene without showing any symptoms. This test is crucial for preventing the breeding of two carriers, which could produce affected puppies

In addition to Progressive Retinal Atrophy (PRA), the OFA Companion Animal Eye Registry (CAER) exam looks for many other heritable eye disorders known to affect Dachshunds. During the annual examination, a veterinary ophthalmologist screens for conditions involving the eyelids, cornea, and lens, some of which are more significant than others. 
Conditions of the retina

• Canine Multifocal Retinopathy (CMR): An inherited retinal disease that causes lesions to form on the retina of a puppy, typically at just a few months old. In Dachshunds, the most common form is CMR3. It does not typically progress after one year of age and causes little or no vision loss.
• Retinal Dysplasia: This condition is a malformation of the retina, resulting in retinal folds. The severity ranges from small, insignificant folds to larger detachments that can cause blindness. 

Conditions of the lens

• Cataracts: While cataracts are common in older Dachshunds, those that occur early in life can have a genetic component. The ophthalmologist will note any opacities in the lens. Significant cataracts can cause vision impairment or blindness.
• Persistent Pupillary Membrane (PPM): This congenital defect occurs when remnants of the fetal blood vessels in the eye fail to regress normally. While many cases are mild and have no effect, severe cases can affect vision or cause corneal opacities where the strands of tissue attach. 

Conditions of the cornea

• Corneal Endothelial Dystrophy: This progressive disease typically affects middle-aged Dachshunds. It involves the breakdown of the cell layer that regulates fluid balance in the cornea, leading to fluid buildup and a cloudy-blue appearance. There is no cure.
• Immune-mediated Keratitis: Also known as punctate keratitis, this inflammatory disease causes multiple inflamed areas on the cornea. It can be treated with medication, but typically requires lifelong management. 

Conditions of the eyelids

• Distichiasis/Ectopic Cilia: These related conditions involve extra eyelashes growing from an abnormal location.
  • Distichiasis: Eyelashes grow from the margin of the eyelid and can irritate the cornea. The severity depends on the number and stiffness of the lashes.
  • Ectopic Cilia: A single or multiple hairs grow abnormally through the inner surface of the eyelid, causing pain and corneal ulcers.
• Entropion: A condition where the eyelid rolls inward, causing irritation from normal eyelashes and hair rubbing against the surface of the eye. 

Conditions related to merle genes

• Merle gene disorders: For Dachshunds with the merle (or dapple) pattern, breeding can be complicated. Dogs with two copies of the merle gene (double dapples) are at a higher risk for eye and hearing problems, including micropthalmia (abnormally small eyes) and other visual defects. 

How breeders use the CAER exam
For many of these conditions, the ACVO Genetics Committee provides specific breeding recommendations to help responsible breeders make informed decisions. 

• Public database: Passing results are published on the OFA website, helping breeders prove they are testing for inheritable eye conditions.
• Breeder options: For minor conditions like mild distichiasis, the CAER exam might indicate "breeder option," meaning the ophthalmologist has noted a minor issue, but it does not necessarily prevent the dog from passing the exam or being bred.
• No breeding recommendations: For more significant diseases with a heritable component, such as progressive retinal atrophy or severe cataracts, the committee may recommend against breeding.
• Genetic testing: When available, DNA tests for specific conditions can be used in combination with the eye exam to identify carriers and prevent passing on inherited disorders

Progressive Retinal Atrophy (PRA) is a group of inherited, degenerative eye diseases that commonly affect Dachshunds and eventually cause blindness. Dachshunds are susceptible to multiple types of PRA, including one specifically identified in Miniature Long-Haired Dachshunds. The condition is not painful, and most dogs adapt well to their vision loss because it progresses slowly

How PRA affects Dachshunds
In Dachshunds, as with many other breeds, PRA follows an autosomal recessive inheritance pattern. This means that a dog must inherit the specific mutated gene from both parents to be at risk of developing the condition. 
The retina, located at the back of the eye, contains specialized light-sensitive cells called photoreceptors. 

• Rods: Detect low light and motion, enabling night vision.
• Cones: Detect color and are important for daylight vision. 

Most forms of PRA first cause the rod cells to degenerate, leading to initial night blindness, followed by the cones, which causes day blindness. The age of onset and rate of vision loss varies by the specific genetic mutation. For example, the cord1 mutation, associated with Miniature Long-Haired Dachshunds, often begins affecting dogs in early to middle age. 

Symptoms of PRA
Because PRA is a slow, progressive condition, signs may not be obvious at first. Owners often notice problems when their dog is in low-light environments. Common symptoms include: 

• Hesitancy to go into dark rooms or outside at night.
• Bumping into objects, especially in unfamiliar or dimly lit areas.
• An abnormally bright, reflective eye shine, especially when light hits the eyes.
• Dilated pupils that react slowly to light.
• Cataracts can develop in the later stages of the disease

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Breeding a Dachshund with one copy of Progressive Retinal Atrophy 5, PRA5/CRD4/CORD1

You can breed a Dachshund with one copy of the PRA5 gene, but only if its mate has been genetically tested and confirmed to be clear of the mutation. This responsible breeding strategy is known as "carrier to clear" and prevents the production of affected puppies. 

Understanding PRA5 inheritance
PRA5 is a late-onset form of progressive retinal atrophy that affects Dachshunds and other breeds. It is inherited in an autosomal recessive manner, which means:

• Carrier dogs have one copy of the gene mutation but do not develop the disease themselves.
• Affected dogs inherit two copies of the gene mutation, one from each parent, and are at risk of developing vision loss. 

Offspring outcomes of a carrier-to-clear breeding
When a Dachshund carrying one copy of the PRA5 gene is bred to a clear Dachshund (with no copies), the following outcomes are expected:

• 50% of the puppies are statistically likely to be carriers, inheriting one copy of the mutation.
• 50% of the puppies are likely to be clear, inheriting two normal copies of the gene.
• Zero puppies will be affected by PRA5 and at risk of developing the disease

​DM is a progressive and incurable disease of the spinal cord mainly found in older dogs, especially Dachshunds.  The dog will gradually loose muscle mass & the ability to walk, starting with the back end.  This sometimes leads to difficulties in breathing, swallowing and possible paralysis.  DM is rarely seen in younger dogs,  and is more likely to be detected between 4-14 years, but usually after 8.
​Degenerative Myelopathy can be compared to ALS or Lou Gehrig's Disease in humans.  The exact cause is unknown, other than it is neurological and hereditary.
Earlier signs of DM would be wobbliness, , difficulty getting up, knuckling and weakness.  There is no cure for DM, however under veterinarian supervision it can be managed with physical therapy and supportive care.
It is not very common in Dachshunds, and most test clear.  However, 1.30% have tested as a carrier with less than 0.1% were noted at risk.  DM can display similar symptoms to IVDD, however they are two separate disorders that require different treatments for a good quality of life.  Although it is rare, it is still best to have a genetic DNA test done if you were looking at breeding.  The risk is small, but it's still a risk.  Two carriers should never be bred together. 

Genetic testing is no longer relatively new, and is vastly available.  It is affordable, and should be done by every single dog bred to make the best choices in choosing an appropriate mating.  Breeding should only be done if it is an improvement in one form or another.  Now that this is readily available there is no excuse why a breeder does NOT genetically test their dog before breeding.
Genetic Testing is not fool-proof, and does not give you a 100% without  a doubt guarantee that your dog is not affected or carries any of the ailments tested for.  Not all diseases can be tested for, mutations happen, complex inheritance, and environmental & nutritional factors can skew results as can false positive/negatives.

Genetic Testing does allow for breeders to make more informed decisions when choosing a mating pair.  Allowing the higher probability to avoid a disorder by not breeding two carriers together.  This also allows for pairing (or not) of certain genetic traits and colorations.  It also allows for early detection of some ailments and allow for Owners and their Vets to make future plans for a healthy good quality life for the pet.
Just because the parents are tested, does not mean you can get away with not testing the offspring.  Things change, as stated above, Mutations, Complex inheritance, environmental and nutritional factors.  Any breeder that tells you the parent is not tested because the grandparents are, is incorrect, and does not have proper knowledge of that parent dogs health.  The accuracy and advancement of genetic testing depends on the continuation of testing through the generations.  Science is always evolving.  Always improving.

In addition to Genetic DNA testing, parent dogs should also be be evaluated by the Orthopedic Foundation for Animals by breed specific recommended tests.  The OFA looks at the dogs Orthopedic Health.  OFA was the original health testing, before genetic testing became readily available.  Using both OFA and DNA together allows breeders to make even better informed choices.  Breeders who are transparent with these results, show owners they are dedicated to ongoing health and well being of what they produce.  

In conclusion, I feel that genetic testing is a valuable asset to your dog's general health routine.  Weather you are breeding or not.  The average cost of genetic testing is about $100-$200, depending on all you want to see results for.  This amount is basically the same as the average cost of vaccines for your pet for his/her first year.  If you are going to spend that to ensure your pet has a higher probability to be protected from Parvo, why wouldn't you also check for things that could pop up later, and be prepared?
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I have started going down this rabbit hole of health testing for Dachshunds.  I knew the basics of what was recommended, but really what do they need and why?  This lead me onto so many different subjects, articles and information that my mind was spinning!  But yet, oddly enough I was still curious and wanted more.  
In a simple short week I have learned what it means to have a CHIC number.  I have heard of it before, when we had the Danes, but never thought much of it.  I felt that having the OFA testing was important, but with the Danes, I was on the fence on the accuracy of the results as so many factors go into play.  Genetic testing wasn't readily available (and affordable), as it is today.  Now I have had all my Dachshunds genetically tested for breed, health, color and even traits.
But there is more I can do to ensure the pups I produce have a better quality at life.  There is more I can provide my puppy owners that I have taken the time and effort to put forth to ensure their new family member will be with them a long time.  I am hoping the information I find, and put into these articles help someone besides me.  Maybe a person looking to buy, or a breeder wanting to do better.  
The following blog is basically my notes, my findings, the information I feel is important to know as a Dachshund Owner and Breeder.  I will post links at the bottom of each, sharing where I obtained the information.  If you found opposing information, new information, or anything relevant do not hesitate to share!  This is a learning adventure!  There is always a different view and new information found.  Learning never ends.  I will NOT be offended!!!  

My first article will discuss the genetic DNA testing, followed by a break down of each of the main disorders/diseases Dachshunds are tested for.