1. From the Tennent Institute of Ophthalmology, Gartnavel General Hospital, Glasgow, Scotland, United Kingdom; the
2. University Department of Pathology, Royal Infirmary, Glasgow, Scotland, United Kingdom; the
3. Department of Microbiology, University of Glasgow, Glasgow, Scotland, United Kingdom; and the
4. University Department of Pathology, Western Infirmary, Glasgow, Scotland, United Kingdom.