Ocular complications after therapeutic irradiation.

At one time radiotherapy had a sinister reputation amongst ophthalmologists because of the frequent and often disastrous sequelae of ocular irradiation; cataract was common, the eyelids and the eye-ball sometimes underwent necrosis, and very occasionally malignant changes developed in irradiated tissues. Over the years increasing knowledge of the effects of radiation, refinements in techniques and dosage, and the development of protective devices associated with increasing liaison between eye surgeons, radiotherapists, and physicists have established the place of radiation in the treatment of eye disease. Radiotherapy now has an accepted and increasingly important place in the treatment of intraocular tumours, particularly retinoblastoma, malignant melanoma of the choroid, and secondary deposits from primary tumours elsewhere in the body (Bedford, 1968) rhabdomyosarcoma of the orbit (Sagerman, Cassady, and Tretter, 1968), and also external ocular neoplasms such as basal and squamous-cell carcinoma of the eyelids and certain melanotic lesions (Lederman, I958). Apart from these malignant conditions, several non-malignant diseases have been treated in the past, but at present radiotherapy is being used in only a few, such as certain cases of vernal catarrh and rosacea keratitis (Lederman, I957), pterygium (Hilgers, I966), and corneal vascularization following keratoplasty (Leigh, I966). Complications may arise with all forms of radiotherapy but vary with the different ocular tissues involved and the form of radiation used. Some of these effects are transient and insignificant; others are permanent and may or may not impair the structure or function of the eye. This account is based on a study of side-effects observed in cases of eyelid and ocular tumours treated in the Tumour Unit ofMoorfields and St. Bartholomew's Hospital, London. Clinically, the complications which may arise in some patients after therapeutic irradiation of the eye and adjacent structures may be divided into two groups: