Ophthalmomyiasis is a rare medical condition characterized by the infestation of the eye by parasitic fly larvae, also known as maggots. This occurs when certain fly species accidentally deposit larvae near or directly onto human eyes. While uncommon, it is a unique parasitic infestation.
Understanding Ophthalmomyiasis
Ophthalmomyiasis involves the invasion of eye tissues by fly larvae. These larvae are typically deposited by adult flies from species like Oestrus ovis (sheep botfly), Hypoderma (cattle botfly), or Dermatobia hominis (human botfly). Humans can become accidental hosts, with larvae entering the eye through direct contact or transfer from contaminated hands. Though larvae usually don’t fully develop in humans, their presence causes irritation and damage.
How Ophthalmomyiasis Affects the Eye
Ophthalmomyiasis affects the eye differently based on where the fly larvae settle. Medical professionals categorize these infestations into types based on the larvae’s location, each presenting distinct symptoms.
Ophthalmomyiasis externa
Ophthalmomyiasis externa involves larvae infesting external eye parts, such as the conjunctiva or eyelids. Symptoms often include a sudden foreign body sensation, intense itching, redness, tearing, and swelling. Patients may also experience irritation, burning, and discharge, sometimes mimicking common conjunctivitis.
Ophthalmomyiasis interna
Ophthalmomyiasis interna is a more serious form where larvae penetrate the eyeball itself, entering structures like the anterior chamber, vitreous, or subretinal space. This internal presence can lead to severe symptoms, including significant vision loss, floaters, and eye pain. It may also result in serious complications such as vitreous hemorrhage, retinal detachment, or intraocular inflammation if the larva dies within the eye.
Ophthalmomyiasis orbitalis
Ophthalmomyiasis orbitalis occurs when larvae infest the tissues surrounding the eye, rather than the eyeball itself. This type of infestation can lead to considerable swelling and pain in the periorbital area. The larvae’s presence in these tissues can cause damage to surrounding structures, resulting in symptoms like eyelid edema, redness, and discharge.
Identifying and Treating the Infestation
Diagnosing ophthalmomyiasis involves a thorough visual examination, often using a slit lamp to identify larvae. A detailed patient history, including recent travel or animal exposure, is also important. Early diagnosis helps prevent the condition’s progression and complications.
Treatment focuses on physically removing larvae from the affected eye. For external infestations, larvae are manually removed using fine forceps after applying topical anesthetic drops. Topical antibiotics are prescribed to prevent secondary infections, and topical steroids may manage inflammation.
For internal ophthalmomyiasis, surgical intervention may be necessary to extract larvae from the eyeball. For orbital myiasis, manual removal may be aided by topical agents to immobilize larvae, followed by oral and topical antibiotics. Prompt treatment reduces discomfort and prevents severe ocular complications.
Reducing Your Risk
Individuals living in rural or tropical areas, particularly those involved in outdoor occupations like farming or shepherding, face an elevated risk of ophthalmomyiasis due to increased exposure to flies. People with poor hygiene, close proximity to animals, or compromised immune systems may also be at higher risk. Cases have been reported globally, including in the United States, often linked to exposure to livestock or wildlife.
To minimize the chance of infestation, several preventive measures can be adopted. Wearing protective eyewear, such as glasses or goggles, when working in environments with high fly activity can help shield the eyes from direct contact with adult flies. Maintaining good personal hygiene, especially in areas where flies are prevalent, can also reduce the risk. Awareness of fly behavior and avoiding environments known to harbor large fly populations, such as near garbage receptacles, can further aid in prevention.