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Iododeoxyuridine (IDU), introduced 9 years ago, was the first antiviral drug to be used effectively and without significant toxicity in the treatment of a human viral disease (Kaufman, Martola, and The presence of IDU halts the reproduction of herpes simplex virus, presumably by competing with thymidine in the synthesis of the viral desoxyribonucleic acid (DNA), and thereby producing a fraudulent DNA that cannot replicate.A biological effect of ultraviolet light on DNA is to cause dimerization of thymine molecules and the extrusion of the dimerized molecules from the DNA (Setlow and Carrier, I 964). Theoretically, therefore, the effectivity of IDU could possibly be potentiated by the simultaneous exposure of the DNA virus to ultraviolet light and IDU since more of the thymidine competitive agent would be utilized by the regenerating virus to replace the extruded thymine.Ultraviolet radiation has other desirable features for the therapy of superficial herpes simplex keratitis, and has been used alone in the treatment of this condition (Hudnell and Chick, I 962; Andrzejewska and Obukowicz, I 966). The advantageous qualities include: (i) Direct viricidal activity resulting from damage of the exposed viral DNA;(2) The destruction of diseased epithelial cells in the ultraviolet superficial keratitis.These cells, harbouring virus, subsequently desquamate, giving rise to a photochemical debridement; (3) The possible stimulation of interferon production.It has been established that the most effective wavelength of the ultraviolet band to produce damage to DNA in bacteria and viruses is in the vicinity of 2,650 A, with a small but insignificant decrease at 2,537 A (Sharp, I939;Phillips and Havel, 1956; Hudnell and Chick, I962) (Fig. i). The spectral limits of the band capable of inducing photochemical keratitis were found to be 2,400 A and 3,050 A, with peak effect at 2,880 A (Cogan and Kinsey, 1946). Kinsey (I948) determined the spectral transmission of the eye to ultraviolet radiations and found that only 26 per cent. of the energy of 2,537 A incident on the corneal epithelium reached the stroma, and none reached the aqueous humour. Such

Closure of the optic cleft occurs about the sixth week of intrauterine life. Clinically, failure of complete closure results in a coloboma of the uveal tract which is variable in its position and extent, and there is sometimes also an associated coloboma of the optic nervehead; defective closure of the cleft is known to be under genetic influence. The usual mode of transmission of such a defect is dominant, but a recessive inheritance, a probable sexlinked transmission (Goldberg and McKusick, I97 i), and an apparently sporadic incidence have also been described. The extensive literature on the subject is reviewed by Franqois (196 I) and Waardenburg, Franceschetti, and Klein (196 I). There has been a high degree of phenotypic variability in all modes of transmission, and this variability has increased with the documentation of syndromes caused by abnormal chromosomes. Most chromosomal defects occur before zygote formation. The primary causations of colobomatous syndromes thus have their origins before fertilization and not during intrauterine development (atypical colobomata excluded).The present paper describes the colobomatous syndromes that have presented at The Hospital for Sick Children, Great Ormond Street in the last io years.Results 25 case histories were examined. Uveal coloboma was an isolated finding in five instances. The findings in the other twenty are summarized in Table I. The systemic associations are divided into five groups for simplicity of discussion, and to show their relationships to previously described associations. The grouping is not intended to display necessarily different syndromes. There is considerable overlapping of associated findings. All cases in Group A have uveal coloboma and cleft lip and/or cleft palate. All cases in Group B have uveal coloboma and oligophrenia. Group C probably represents two further cases of the oculo-anal syndrome which has received scant attention since its original description by Haab (1878). Group D represents two cases of hypersplenism with uveal coloboma, an association not recorded previously in the literature. Group E concerns two miscellaneous cases which may represent a partial expression of those represented elsewhere in the series.One of the patients with isolated uveal coloboma had a sibling with a congenital dislocation of the hip, and another had a sibling and an aunt with bilateral anophthalmos.

Most multiple congenital abnormality syndromes associated with uveal colobomata have their origins dating from before intrauterine development. Causative genetic and chromosomal influences were reviewed (James, Karseras, and Wybar, 1974), but associated abnornalities of the sex chromosomes were not observed in their series and are a rare occurrence in the literature. It is of interest therefore to record uveal colobomata occurring in a patient with Klinefelter syndrome and to discuss the possible implications. This association has not been recorded in Britain previously. Material and methods CASE REPORTA z7-year-old White youth presented with concemr about the lack of development of his external genitalia. Bilateral iris colobomata had been noted at birth and he had attended an ophthalmologist from that time. He had been wearing contact lenses for three years.The parents were unrelated and there was no family history of ocular abnormality. Examination of both .. a l parents revealed normal eyes. The father and mother were both 45 years old at the time of his conception.There was one normal brother, three years older, and the mother had had a diagnostic x-ray of the pelvis luring the pregnancy of this child. uxillary hair was scanty and pubic hair had a female listribution (Fig. 3). There was a mild gynaecomastia