CHAPTER TWO 30 reasonable to collect additional information whenever a person with selected characteristics was identified. Ancillary study protocols concerning cataract and aphakia (i.e., absence of the lens), trachoma, xerophthalmia and keratomalacia, and eye trauma were administered to persons identified with those conditions in survey sites. Ophthalmic, epidemiologic, behavioral, social, and other data were collected by the ophthalmologist, the medical officer, or specially trained enumerators. Design of the ancillary study protocols, as well as the examination protocol, are described in more detail later. There were three levels or hierarchies of data collection in the site. Enumerators collected data on the site itself through inter- views conducted with significant persons in each site (e.g., ward chiefs, teachers) and recorded the findings on a standard form (Form 1). The next level of data collection was at a household level, for which information about caste, religion, ethnic group, water sup- ply, migration history, health services utilization, and other characteristics of the household was obtained from a responsible person in the household (typically a female 18 years or older) and recorded on the household register (Form 2). The third level of hierarchical data, person-level data, included a limited amount of background in- formation collected on each person at the time of household enumeration. Besides recording the data on the household registry, enumerators also recorded the person-level data on the top of the eye examination proforma (Form 3). The ophthalmic assistant and ophthalmologist subsequently recorded findings of the eye examina- tion on the same form. A fourth and final level of data collection is the ancillary study protocol. Persons with selected conditions were administered ad- ditional protocols and the findings recorded on appropriate forms (Forms 4 through 9).• In order to assist in the training of staff, and to provide working documents in the field, a series of manuals and guides were prepared for various staff. An enumerator's manual was written, describing in detail the enumerator's duties and responsibilities, in- cluding a question-by-question summary for the ward- and household- level forms (Forms 1 and 2), and instructions on how to complete the top portion of the eye examination proforma (Form 3). An examiner's manual was also prepared, establishing the eye ex- amination protocol and detailing the appropriate coding for various signs that were to be recorded. Finally, an operational guide was written, which served as the basic document describing the roles of all field staff in conducting the survey activities. Design of Examination Protocols and Proformae: The develop-
