VISUAL STANDARDS
ASPECTS AND RANGES OF VISION LOSS

This 35-page report was prepared for and adopted by the International Council of Ophthalmology at its meeting in Sydney, Australia, in April 2002.

The goal of the report is to give a voice to emerging areas of consensus by providing guidelines for the uniform use of definitions, measurements and reporting methods.

The goals of population surveys have expanded from a study of the causes of truly "blinding" eye diseases to a study of lesser levels of vision loss that no longer fit under the term "blindness." The project title of the current WHO project "Vision 2020--the Right to Sight" reflects this shift.

Most conditions can be approached from different points of view. Thus, different observers will see different aspects. The four aspects recognized in ICIDH-80 and ICF are helpful to bring order among the many possible points of view when discussing the causes and consequences of Vision Loss. For each aspect, different ranges of loss need to be recognized.

For visual acuity loss the ranges in ICD-9-CM can serve this purpose. These ranges also fit well with a classification of visual ability loss (e.g. reading ability).

Similar ranges can be developed for visual field loss. The recently revised AMA Guides (5th edition, 2001) provide a means of calculating statistical ability estimates, based on measured acuity and field loss.

The Council recognizes the ETDRS protocol of the National Eye Institute as the de-facto international standard for visual acuity measurement.