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Swiss

FAQs – Cats with Anophthalmia or Microphthalmia

If you are thinking about adopting a cat with Anophthalmia or Microphthalmia (The absence of one or both eyes. Both the eye ball and the ocular tissue are missing from the orbit, or abnormally small eyes) DO IT! It will be life-changing. 

Anophthalmia and Microphthalmia are quite rare. When I adopted Swiss, there was very little information out there on his condition. I spent a lot of time on the phone with the vet, and did a TON of research myself. Thankfully, with the few resources I was able to find, he grew up to be the most handsome, well behaved little boy.

I could not find statistical data for cats and anophthalmia, but here are some human statistics:

  • 3/100,000 Births
  • 2/3 Cases are found to be genetic
  • Accounts for 3-11% of blindness in children

I don’t want anyone to have to worry as much, or search as hard as I did, so here are some frequently asked questions that I get about cats with anophthalmia and microphthalmia. With questions/concerns please feel free to email me at [email protected]

What causes anophthalmia? 

  • Genetics – Anophthalmia is autosomal dominant, and can be caused by a mutation of the SOX2 gene. The mutation prevents the gene from producing an important protein that leads to the development of the eye. In order to inherit this mutation, the animal only needs the mutated gene from one parent. There are 33 different mutations of this gene, and not all will cause microphthalmia, or anophthalmia.
  • Missing Chromosome – Occasionally anophthalmia and microphthalmia have been found to be caused by the deletion of chromosome 14. Other characteristics of the deletion of chromosome 14 are undescended testes, a small tongue, and other bodily growth retardation.
  • Infection *MOST COMMON IN CATS FOR MICROPHTHALMIA* – Anophthalmia and microphthalmia can be caused by a virus during fetal development; most commonly, toxoplasmosis and certain forms of kitty influenza.
    • How does the pregnant mother get toxoplasmosis: 
      • Coming into contact with, or ingesting, an infected animals fecal matter.
      • By eating infected meat.
        • ***TOXOPLASMOSIS IS WHY PREGNANT WOMEN ARE NOT RECOMMENDED TO CLEAN LITTER BOXES***

Does is hurt the animal?

Yes, if an infection is still present. But otherwise, no – these are not painful conditions. The cat likely doesn’t know that there is anything wrong.

Does the animal have a hard time finding its food, or its litter box? 

No, these animals use sensory substitution. This means they use sensory information from other parts of the brain to make up for the the visual deficit. It is possible that they will have more brain development in the auditory processing areas, and they do have heightened auditory spatial abilities.

Basically, these are almost normal animals! They may occasionally get stuck and not know how to get down when they climb on things, but you can feel comfortable knowing that you don’t need to feel sorry for them. They are happy and healthy, and EXTRA cute. =) They will amaze you on a daily basis with the things that they can accomplish without sight, like hunting bugs, and running through the house at full speed! Don’t write them off due to their facial abnormalities. 

DISCLAIMER: I am not a medical professional.

References: 

Tabry, V; Voss, P.; Zatorre, R.J; (2013) The influence of vision on sound localization abilities in horizontal and vertical planes. Frontiers in Psychology 2013: 4(932) DOI:10.3389/fpsyg.2013.00932

Shiell, Martha; (2014) Tonotopic organization of v5/mt+ in congenital anophthalmia: Implications for auditory motor processing and meta-modal cross modal reorganization. The Journal of Neuroscience 2014: 34(11) DOI: 10.1523/jneurosci.0150-14.2014

The Amazing Dr. Gray at Gentle Vet Animal Hospital, Green Bay WI.