The World Health Organization (WHO), being concerned about the difficulty of granting support and subsidies, based it on a clinical criterion to objectify the definition of visual impairment. Thus, an individual can be considered visually deficient taking into account Visual Acuity (VA) and / or Visual Field (VF) assessment.
In Portugal, and in most European countries, low vision is usually divided into:
Moderate or partial
Visual Acuity (VA), in the best eye and after the best conventional optical correction, between 1/10 and 3/10 without any changes in Visual Field (VF).
Severe or residual
Although the WHO international definition of visual impairment is considered in Portugal, but the existing legislation for medical and legal assistance has not yet been updated. Therefore, in Portugal and accordance to Decree-Law no. 49331/69 of October 28, legally blind individuals are those whose VA after conventional correction is not higher than 1/10 and / or whose VF is lower or equal to 20 degrees.
An individual with visual pathology and low vision presents an increased effort when using the visual residues in the day-to-day tasks. Therefore, low vision should not only be defined by VA and VF but also by visual efficiency and functional vision.
From a functional point of view, whenever vision loss is severe enough to interfere with the tasks and activities of daily living, and it is not possible to correct them with conventional or contact lens, then it is necessary to intervene through rehabilitation and the use of technical auxiliaries.
Thus, with orthoptic rehabilitation integrated into the Low Vision consultation, we aim to improve the use of residual vision of individuals, attenuating visual fatigue and handicap, promoting and facilitating autonomy and integration in society.