Vision loss is too often accepted as a "normal" part of the aging process by both professionals and the aged themselves. As a result, older people tend not to actively seek or be referred to vision rehabilitation services. Aggressive outreach efforts are required to break down these barriers which impede early identification of emerging vision disabilities. Screening instruments, which can be easily and quickly administered, are critically needed to implement such a strategy.
The Functional Vision Screening Questionnaire (FVSQ) was developed several years ago as part of an educational and outreach project for older people in the community. The objective was to develop an instrument that could facilitate early identification of vision problems and referral for comprehensive clinical evaluations. The questionnaire consists of 15 items which focus on functional, rather than clinical, indicators of vision problems.
The FVSQ was administered to the patient population (n=265) of an ophthalmologist whose practice includes low vision patients. Clinical data on the patients' visual acuities, eye diseases, visual fields, contrast and glare problems, and need for low vision devices were collected. Patients are defined as visually impaired based on best corrected distance acuity of 20/70 or worse or best corrected near acuity of greater than 1.25. Using these criteria, 18% were classified as visually impaired. The primary analytic method for evaluating the FVSQ is an expectancy table analysis in order to identify the scale value (i.e., cut-score) most appropriate for defining the probability that an individual is visually impaired.
Results indicated that a cut-score of 9 (i.e., respondents reporting problems in at least 9 of the 15 items) was most appropriate for screening purposes. At this value, 90.6% of all 265 cases were correctly classified. Furthermore, at a cut of 9: the sensitivity was .72 (i.e., 72% of all the truly impaired were identified by the screen); the specificity was .94 (i.e., 94% of the truly not impaired were identified as not impaired by the screen); the positive predictive value was .74 (i.e., of all those identified by the screen as impaired, 74% were truly impaired); and the negative predictive value was .94 (i.e., of all those identified by the screen as not impaired, 94% were truly not impaired). Both higher and lower cut scores were rejected because they tended to increase negative qualities of the screening questionnaire without sufficient gains in other aspects.
The data provide support for the index's efficiency and effectiveness as a vision screening tool which can be used in community outreach programs to identify visually impaired older people who should be referred for clinical follow-up. With funding from the National Institute on Disability and Rehabilitation Research, the FVSQ is available in German, French, Spanish, Creole-French, Chinese, Russian, and Hindi.
Horowitz, A., Teresi, J., & Cassels, L. A. (1991). Development of a vision screening questionnaire for older people. Journal of Gerontological Social Work, 17, (3/4), 37-56.
Horowitz, A. (1998). Validation of a functional vision screening questionnaire for older people. In Vision '96: Proceedings of the International Low Vision Conference, (pp. 492-494). ONCE: Madrid, Spain.
Investigators: Amy Horowitz, DSW/PhD, Principal Investigator Eleanor E. Faye, MD, Co-Investigator Robin McInerney Leonard, MA, Research Associate.