Ocular larva migrans

Ocular Larva Migrans (OLM) is a medical condition that occurs when larvae of certain parasitic nematodes, primarily the Toxocara canis (dog roundworm) or Toxocara cati (cat roundworm), migrate to the eye. This condition is a form of visceral larva migrans, a more generalized infection by the same parasites, but OLM specifically affects the eyes and vision. It is considered a serious ocular disease that can lead to permanent vision loss if not treated promptly.

Causes and Transmission

Ocular Larva Migrans is caused by the accidental ingestion of eggs of the Toxocara species. These eggs are found in the environment, particularly in soil contaminated with the feces of infected dogs or cats. Children are especially at risk due to their play habits, which may involve contact with contaminated soil, and their tendency to put their hands in their mouths without washing them.

Symptoms

The symptoms of OLM can vary depending on the part of the eye affected. Common symptoms include:

• Visual impairment or vision loss
• Eye redness and pain
• Leukocoria (white pupil)
• Strabismus (misalignment of the eyes)
• Uveitis (inflammation of the uveal tract of the eye)

Diagnosis

Diagnosis of Ocular Larva Migrans involves a combination of patient history, clinical examination, and specialized tests. These may include:

• Ophthalmoscopy to examine the back of the eye
• Blood tests to detect antibodies against Toxocara
• Imaging tests such as ultrasound or MRI of the eye

Treatment

Treatment for OLM typically involves anti-inflammatory medications to reduce eye inflammation and, in some cases, antiparasitic drugs to kill the larvae. Surgical intervention may be necessary to remove larvae in severe cases or to treat complications such as retinal detachment.

Prevention

Prevention of Ocular Larva Migrans focuses on minimizing the risk of Toxocara infection. Measures include:

• Regular deworming of pets
• Avoiding contact with soil that may be contaminated with animal feces
• Practicing good hygiene, especially handwashing before eating

Epidemiology

OLM is more common in areas with high populations of stray dogs and cats and in regions with poor sanitation practices. Children and individuals with close contact with soil are at higher risk of infection.