Heterotopia of the macula.

Derzhavin (1896) described the first recorded case, with a vascularized band extending from the whole width of the optic disc to the periphery of the retina, which at first formed a retinal fold and then broke free from the retina as a band extending forwards into the vitreous. It has been suggested that this represented remnants of the hyaloid artery. Grondahl (1963) has reported a child with unilateral heterotopia of the macula due to atypical ablatio falciformis congenita. The child described by Woillez, Fran9ois, and Lebrun (1960) had a vascularized retinal traction band and was probably a further case of atypical falciform congenital fold producing heterotopia ofthe macula. Triebenstein (1919) ascribed his two cases, in a mother and her son, to congenital causes of a developmental anomaly, though the description of the fundal lesions would suggest that they were postinflammatory. Cohen and Weisberg (1950) thought that their case of bilateral heterotopia of the macula was due to disturbances in the rate of growth and maturation of the retinal structures. Post-operative displacement of the macula has been known to follow retinal detachment surgery, as in the case described by Stein (1931). The majority of cases of macular heterotopia are due to traction bands (Duke-Elder, 1964), which may result from trauma, as in the case described by Friedman (1942), where a macular scar was thought to have followed a retinal haemorrhage during birth. Incomplete retrolental fibroplasia has been incriminated as the cause in many of the cases recorded in the literature, particularly in two of the cases mentioned by Payne and Pitts-Crick (1956) and most or all of the eight cases reported by Rados and Scholz (1958). Blaxter (1951) described a unilateral case which he ascribed to old chorioretinitis, but the child had been born prematurely and a vertical squint involving the affected eye, which was slightly microphthalmic, had been noted since the age of 18 months. Hugonnier and Royer (1958) reported a further bilateral case due to incomplete retrolental fibroplasia in a child, who at the time of presentation had a uveitis associated with a primary tuberculous complex. The uveitis settled rapidly on steroid and antibiotic therapy and the ectopic maculae, associated with retinal folds due to incomplete retrolental fibroplasia, could then be seen. This case and another of uncertain aetiology were mentioned in greater detail by Michel (1959) in his thesis on ectopia of the macula in which he gives an extensive review of the literature. The third case reported by Payne and Pitts-Crick (1956) appears to have begun as a result of retinal periphlebitis and subsequently to have been exaggerated by a diathermy operation performed for the periphlebitis.