Ocular myiasis, occurs when fly larvae land on the eye and sometimes burrow into deeper tissues. This condition causes sudden eye irritation, redness, tearing, light sensitivity, and the sensation of movement across the ocular surface. Untreated cases may lead to severe inflammation, vision changes, or even retinal damage.
As Dr. Jennifer Tsai, known as "@drjenandjuice" on Instagram who is a board-certified optometrist, explains, “Ever seen a tiny fly larva invading the eye? It sounds crazy but it's a real condition called alveolar myiasis.” This unusual infestation primarily affects people in tropical or rural regions exposed to flies that may lay eggs near or on the eye. 1
Ophthalmomyiasis is a parasitic eye infestation caused by fly larvae, primarily the sheep botfly Oestrus ovis. It manifests as ophthalmomyiasis externa, affecting the conjunctiva and cornea, or ophthalmomyiasis interna, involving deeper ocular structures.
Dr. Tsai notes, “The larva can actually attach to the surface of the eye and in rare cases actually burrow deeper into the tissues.”
For example, a case in Portugal documented twelve Oestrus ovis larvae on the conjunctiva, successfully removed with topical anesthesia and follow-up antibiotic treatment. 2
Persistent foreign body sensation in the eye
Redness (conjunctival hyperemia)
Excessive tearing (epiphora)
Itching and irritation
Swelling of the eyelids or conjunctiva
Sensitivity to light (photophobia)
Mild eye pain in some cases
Dr. Tsai summarizes the warning signs: “Symptoms include sudden eye irritation, redness, tearing, light sensitivity, and the sensation of something moving on the eye.
In more severe cases it can cause vision changes, inflammation, and even damage to the retina if not treated quickly.” Awareness of these symptoms is critical, especially in endemic areas where ocular infections can mimic conjunctivitis. 2
Diagnosis requires careful eye examination, often with slit-lamp biomicroscopy. Larvae tend to hide in the conjunctival fornices and move away from light.
Treatment involves prompt removal of larvae under topical anesthesia, such as proparacaine. Non-toothed forceps or swabs help extract larvae completely. Topical antibiotics and corticosteroids are prescribed to manage inflammation and prevent secondary infections. In selected cases, ivermectin may be used as an adjunct therapy. Severe internal cases may require surgical interventions such as photocoagulation or pars plana vitrectomy. 2
Dr. Tsai emphasizes treatment urgency: “Diagnosis is typically made through an eye exam and the treatment involves removing the larva from the surface of the eye and also prescribing medication to control the inflammation or infection.”
What is Ocular myiasis?
Ocular myiasis is a rare eye condition caused by fly larvae landing on or burrowing into the eye, leading to irritation, redness, and tearing.
How is it diagnosed?
Diagnosis is made through an eye exam, often using slit-lamp biomicroscopy to detect larvae hiding in the conjunctival fornices.
What is the treatment?
Treatment involves careful removal of larvae under topical anesthesia, followed by antibiotics and anti-inflammatory medication to prevent infection and reduce swelling.
References:
1. EyeWiki. "Help: Getting Started." Last modified September 18, 2025. https://eyewiki.org/Help:Getting_Started.
2. Martínez-Rojano, Hugo, Herón Huerta, Reyna Sámano, Gabriela Chico-Barba, Jennifer Mier-Cabrera, and Estibeyesbo Said Plascencia-Nieto. "Ophthalmomyiasis Externa and Importance of Risk Factors, Clinical Manifestations, and Diagnosis: Review of the Medical Literature." Diseases 11, no. 4 (2023) https://pmc.ncbi.nlm.nih.gov/articles/PMC10743177/
(Rh/ARC/MSM)