Myiasis is the infestation of the tissues and organs of animals or man by fly larvae. Ophthalmic myiasis has been reported from various world regions. In this study, we are presenting the clinical manifestations of external ophthalmomyiasis which was caused by the larvae of the sheep nasal botfly, Oestrus ovis, in 10 patients in the Tirunelveli and the Tuticorin districts of Tamil Nadu state India. All the patients were farmers, who worked in close contact with sheep and goats. All the patients presented with severe conjunctivitis. The larvae were observed in the bulbar conjunctiva and following their removal, the symptom of eye inflammation improved in a few hours.

Myiasis is the infestation of tissues and organs of animals or man by fly larvae. We report a human case of external ophthalmomyiasis caused by the larvae of a sheep nasal botfly, Oestrus ovis, for the first time in a veterinary doctor. A 25-year-old veterinary doctor presented with severe symptoms of conjunctivitis. The larvae, 3 in number, were observed in the bulbar conjunctiva and the symptoms of the eye improved within a few hours of their removal. It is important for ophthalmologists to be aware of larval conjunctivitis as a significant possibility in the veterinary fraternity especially during the summer season.

Oestrus ovis or 'sheep botfly' causes common ophthalmomyiasis in warm climates. It is a self-limited infestation with symptoms such as foreign body sensation and/or tearing. The larvae can be observed in the conjunctiva and should be extracted with forceps. The development of larvae beyond the first stage does not occur in healthy humans, although they may penetrate the ocular globe, causing so-called internal myiasis. External ophthalmomyiasis is typical of rural areas, but it may be observed occasionally in urban environments.

A 50-year-old male presented with foreign body sensation, pain, and redness in left eye. Slit-lamp biomicroscopy revealed tiny larvae crawling around the conjunctival sac. The larvae, numbering 13, were mechanically removed under topical anesthesia and identified under light microscope as first-stage larvae of Oestrus ovis causing ophthalmomyiasis externa.

Ophthalmomyiasis is a rare infection seen in susceptible individuals. We report a case of orbital myiasis in squamous cell carcinoma (SCC) in a patient of xeroderma pigmentosum. On presentation, reddish brown ulcerated mass with numerous maggots in orbit were seen. Computed tomography scan showed the presence of soft tissue lesion without any bony destruction. Following debridement, emergency exenteration with sacrifice of eyelid skin was performed. The diagnosis of SCC was confirmed on histopathologic evaluation. The maggots belonged to family Calliphoridae and secondary bacterial infection with Klebsiella organism was identified. Management issues included extensive involvement requiring exenteration, non-availability of skin graft, delayed secondary healing and recurrence of pigmented lesions in skin lining of orbit. The skin grafting was avoided as it can harbour the neoplasm.

To present a case of massive orbital myiasis.An 87-year-old debilitated woman suffering from left ocular pain of four days' duration presented with a severely necrotized left orbit and several attached live larvae. The upper and lower eyelids and the eyeball were completely destroyed. She had history of eyelid surgery in the same eye due to a skin lesion, apparently some type of skin cancer, 15 years before. The larvae were identified as Chrysomya bezziana (Diptera: Calliphoridae) or old world screwworm fly.Infestation of ocular and orbital tissues by fly larvae (ophthalmomyiasis) progresses rapidly and can completely destroy orbital tissues within days, especially in patients with poor general health. Treatment consists of removal of the larvae and surgical debridement.

Ocular myiasis in humans is a rare phenomenon. Here two cases are reported who came to a tertiary care centre with features of unilateral acute catarrhal conjunctivitis. Fly larvae were detected on slit lamp examination and removed after immobilising it with topical 4% lignocaine. Topical antibiotics and steroid drops were prescribed for 2 weeks. The samples were identified as Oestrous ovis by the entomology department of the Institute of Tropical Medicine, Kolkata. The signs and symptoms regressed within 48 hours. The cases are being reported to create awareness among the ophthalmologists regarding larval conjunctivitis especially in developing countries like India, where the general standard of hygiene is low and fly infestation is common.