Drusen of the disc and retinal haemorrhages.

Buried drusen of the optic discs are the main cause of difficulty in the diagnosis of early papilloedema. In a series of 28 cases of pseudopapilloedema, which had been mistakenly diagnosed as papilloedema due to brain tumour, Hoyt found buried drusen to be the major cause of confusion (Hoyt and Pont, I962). Many of his patients had undergone unnecessary and often hazardous investigations, including arteriography, pneumoencephalography, ventriculography, and even burr holes. The rare association between drusen of the optic disc and retinal haemorrhage has only recently received detailed mention eleswhere (Otradovec, and Vladykova 1970; Sanders, Gay, and Newman, 1971) apart from a few isolated reports as an incidental finding. The presence of haemorrhages on or near the disc in association with buried drusen is of course liable to make clinical evaluation even more difficult. Having recently seen two cases of this nature, it was felt important to emphasize the association in the hope of facilitating the interpretation of the clinical signs, thus sparing patients the anxiety and potential hazards of unnecessary investigations. The first report of drusen was a histological study by Nuller (I858). This was followed Io years later by a description of the ophthalmoscopic appearances (Liebreich, i868). Since then many cases have been described and an extensive study with a comprehensive review of the literature was published by Lorentzen (I966). Drusen consist of degenerative deposits of hyaline-like material composed of laminated homogeneous masses which frequently become calcified. They are invariably situated anterior to the lamina cribrosa where they can produce atrophy of the adjacent nerve fibres. The clinical changes are localized to the disc, particularly the nasal aspect, which consequently appears swollen. The disc margins are irregular and blurred and the physiological cup is filled in. There is no hyperaemia and there are no exudates, but in I I per cent. of cases vascular anomalies in the form of arterial or venous loops may be found (Lorentzen, I966). Drusen are bilateral in 72 per cent. of cases, and can occur at any age and in either sex, with an incidence of 3.4 per thousand (Lorentzen, I966). The normal clinical course is one of slow, progressive enlargement over many years. Central vision is almost never interfered with, but field defects can be found in 87 per cent of cases. The characteristic field defects are concentric constriction, baring of the blind spot, and nerve-fibre bundle defects (Lauber, I92I; Rucker, I944; Lansche and Rucker, I957; Lorentzen, I966). Lorentzen described amblyopic attacks in 8 per cent. of his patients, a symptom that had been documented on eight previous occasions (Gifford, I895; Thompson, I898; Cibis, 1940; Chambers and Walsh, I951; Lansche and Rucker, I957; McPherson, I955; Morax, I963; Polliot and Lods, I963).