Microphthalmia and Anophthalmia in Cows

Quick Answer
  • Microphthalmia means one or both eyes are abnormally small at birth. Anophthalmia means the eye is absent or appears absent.
  • These defects are usually congenital, meaning the calf is born with them. Causes can include inherited defects, abnormal fetal development, or in-utero infections such as bovine viral diarrhea virus.
  • Some calves adapt well if only one eye is affected. Bilateral disease can cause major vision loss and raise safety, nursing, and welfare concerns.
  • Your vet may recommend a physical eye exam, herd history review, and testing for infectious or inherited causes before breeding decisions are made.
  • Typical US cost range is about $150-$500 for a farm call and basic exam, $300-$900 with laboratory testing, and $800-$2,500+ if advanced imaging, referral, or surgery is needed.
Estimated cost: $150–$2,500

What Is Microphthalmia and Anophthalmia in Cows?

Microphthalmia and anophthalmia are congenital eye defects seen in calves. Microphthalmia means the globe is smaller than normal. Anophthalmia means the eye is absent, although in some calves there may be a tiny, poorly developed globe hidden within the orbit rather than a complete absence of eye tissue.

These conditions may affect one eye or both. They can occur alone, but they may also appear with other eye abnormalities such as cataracts, retinal dysplasia, detached retina, malformed pupils, or defects of the cornea and lens. In cattle, congenital eye defects have been reported with inherited problems and with fetal exposure to disease during pregnancy.

The day-to-day impact depends on severity. A calf with one small but comfortable eye may function fairly well in a familiar environment. A calf with severe defects in both eyes may have trouble finding the udder, avoiding obstacles, gaining weight, or handling normal herd stress. That is why an early exam by your vet matters, even when the calf seems bright and active.

Symptoms of Microphthalmia and Anophthalmia in Cows

  • One or both eyes look unusually small
  • Eye socket appears empty or sunken
  • Cloudy eye, cataract, or abnormal corneal appearance
  • Misshapen pupil or iris abnormalities
  • Poor vision, bumping into objects, or difficulty navigating
  • Trouble locating the udder or nursing normally
  • Tearing, squinting, or eye discharge
  • Failure to thrive or poor weight gain when vision is severely affected

Some calves show only a visibly small eye. Others have more obvious vision problems, especially if both eyes are affected or if there are additional defects inside the eye. See your vet immediately if the calf is squinting, has discharge, seems painful, is not nursing well, or has other birth defects. Pain, infection, or poor growth can change the care plan quickly.

What Causes Microphthalmia and Anophthalmia in Cows?

These conditions develop before birth, during formation of the eye and surrounding tissues. In cattle, one important cause is genetic or inherited developmental error. Herd-level patterns, repeated cases from related animals, or recurrence when using the same sire can raise concern for a heritable defect.

Another recognized cause is fetal infection during pregnancy, especially bovine viral diarrhea virus (BVDV). Merck notes that in-utero BVD infection can be associated with microphthalmia, cataracts, retinal dysplasia, and retinal detachment in calves. The timing of infection during gestation affects which organs are damaged and how severe the defects become.

Less commonly, poor fetal development may be linked to nutritional or toxic influences during pregnancy, although proving a single cause in an individual calf is not always possible. Your vet may also look for other congenital abnormalities because eye defects can be part of a broader developmental syndrome rather than an isolated finding.

How Is Microphthalmia and Anophthalmia in Cows Diagnosed?

Diagnosis starts with a careful physical exam and close inspection of the eyes, eyelids, and orbit. Your vet will assess whether the calf has a small globe, a hidden malformed globe, or a truly absent eye. They will also look for related defects such as cataracts, corneal opacity, abnormal pupils, or signs of discomfort.

History matters. Your vet may ask about the dam's health during pregnancy, vaccination status, BVD exposure risk, other affected calves in the herd, and whether related animals have had similar defects. If there is concern for infectious causes, testing may include BVD sampling of the calf and herd-level follow-up.

In more complex cases, your vet may recommend ocular ultrasound, photographs for monitoring, or referral to a veterinary ophthalmologist or diagnostic laboratory. If a calf is stillborn, aborted, or has multiple congenital defects, submitting tissues for laboratory evaluation can help clarify whether infection or inherited disease is more likely. That information can be very useful for future breeding and prevention decisions.

Treatment Options for Microphthalmia and Anophthalmia in Cows

Spectrum of Care means you have options. Here are treatment tiers at different price points.

Budget-Conscious Care

$150–$500
Best for: Calves with mild unilateral defects, no obvious pain, and acceptable ability to nurse, move safely, and gain weight.
  • Farm call or clinic exam
  • Basic eye and neurologic assessment
  • Vision and nursing evaluation
  • Supportive management for a comfortable calf
  • Environmental adjustments such as safer pen setup and easier feed access
  • Monitoring for discharge, pain, or poor growth
Expected outcome: Often fair to good for comfort and basic function if one eye is affected and the other eye is normal.
Consider: This approach may not identify the exact cause. It also may miss internal eye abnormalities or herd-level infectious and genetic concerns that affect future breeding decisions.
Most Common

Recommended Standard Treatment

$300–$900
Best for: Most calves with congenital eye defects, especially when both eyes are affected, vision is uncertain, or the herd needs answers about cause and recurrence risk.
  • Complete veterinary exam
  • Detailed ocular assessment
  • BVD testing or herd-level infectious workup when indicated
  • Review of dam history, vaccination status, and related calves
  • Treatment of secondary irritation or infection if present
  • Guidance on prognosis, welfare, and whether to retain or cull from breeding
Expected outcome: Variable. Many calves with unilateral disease can adapt well. Bilateral severe defects carry a more guarded outlook for normal function and long-term productivity.
Consider: Higher upfront cost range than basic monitoring, and some cases still remain unexplained even after testing.

Advanced / Critical Care

$800–$2,500
Best for: Painful eyes, uncertain anatomy, valuable breeding animals, calves with multiple birth defects, or herds needing the most complete diagnostic information.
  • Ocular ultrasound or advanced imaging
  • Referral consultation with a veterinary ophthalmologist
  • Sedation or anesthesia for detailed exam if needed
  • Surgical removal of a painful nonfunctional eye in select cases
  • Laboratory submission of fetal or calf tissues when multiple congenital defects are present
  • Expanded herd investigation and breeding-risk review
Expected outcome: Best for clarifying cause and improving comfort in complicated cases. Functional vision may still be limited if the defect is severe or bilateral.
Consider: More intensive handling, referral access may be limited in rural areas, and advanced diagnostics may not change the fact that congenital eye tissue cannot be restored.

Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.

Questions to Ask Your Vet About Microphthalmia and Anophthalmia in Cows

Bring these questions to your vet appointment to get the most out of your visit.

  1. You can ask your vet whether this looks like true anophthalmia or a very small malformed eye hidden in the socket.
  2. You can ask your vet if the calf seems comfortable and whether vision is likely normal, reduced, or absent.
  3. You can ask your vet whether BVD testing is recommended for this calf, the dam, or the herd.
  4. You can ask your vet if other congenital defects should be checked for during the exam.
  5. You can ask your vet whether this case raises concern for an inherited problem and how that should affect breeding plans.
  6. You can ask your vet what signs would mean the eye has become painful or infected.
  7. You can ask your vet whether referral to a veterinary ophthalmologist would change diagnosis or management.
  8. You can ask your vet what housing or handling changes would help a visually impaired calf stay safe and gain weight.

How to Prevent Microphthalmia and Anophthalmia in Cows

Prevention focuses on herd health, pregnancy management, and breeding decisions. Because some cases are linked to fetal infection, work with your vet on a practical BVD prevention plan. That may include vaccination strategy, testing, biosecurity for incoming cattle, and prompt follow-up if congenital defects or reproductive losses appear in the herd.

Breeding management also matters. If related calves have similar eye defects, your vet may recommend avoiding repeat matings, reviewing sire and dam lines, and removing affected animals or likely carriers from breeding programs when appropriate. This is especially important when a pattern suggests an inherited defect.

Good maternal nutrition supports normal fetal development, although nutrition alone does not explain every case. During pregnancy, make sure cows have a balanced ration, appropriate vitamin and mineral support, and regular herd-health oversight. If a calf is born with eye abnormalities, early documentation and veterinary evaluation can help protect future calves by guiding testing and breeding choices.

Find a Vet Near You