How to check for low vision?

Abstract: the purpose of low vision examination is to enable low vision patients to make full use of residual vision, help low vision patients improve their quality of life and enhance their ability to live independently., , the purpose of low vision examination is to enable low vision patients to make full use of residual vision, help low vision patients improve their quality of life and enhance their ability to live independently. The first is to ask about the general ophthalmic history and treatment process. If the patient requests further treatment and it is determined that it cannot be treated, it should be explained. Most of these patients have recently developed visual impairment. What they consider is how to treat them rather than using visual aids. For patients who have experience of using visual aids, understand their experience of using visual aids. For patients with congenital and hereditary eye diseases, we should ask them about their family history, understand their occupation, life, hobbies and learning, and use different visual aids for different needs. Next, the visual acuity examination is divided into far vision examination and near vision examination. Since the visual acuity of low vision patients is below 0.3, and there are few visual indicators in lines 0.1 and 0.2 of the general international standard visual acuity chart, and the interval is too large, it is best to choose a visual acuity chart with multiple visual indicators in each line and 1 ~ 2 visual indicators between 0.1 and 0.2, such as lighthouse visual acuity chart. In the near vision examination, the international standard near vision chart is often used, but the distance between the eyes and the chart should be recorded. It should also be noted that when checking the vision of low vision patients, in addition to the left and right eyes, the vision of both eyes should be checked at the same time. In terms of refractive examination, we can not subjectively conclude that the patient’s vision is “uncorrectable”, so every patient with low vision must undergo routine and careful refractive examination, including mydriatic optometry, corneal astigmatism, etc. Generally, the visual indicators of the visual acuity chart are black and white, but in real life, it is often necessary to distinguish objects with weak contrast and unclear intensity. This is the problem of contrast sensitivity. For people with the same vision but different contrast sensitivity, they feel completely different in real life, so they need to check the contrast sensitivity, Commonly used, such as Arden chart, etc. Similarly, in addition to black and white objects, the color of objects is also an important factor in recognition. Color perception is a part of people’s visual function, so color perception should be checked. To fully reflect people’s visual function, in addition to the central visual acuity representing the function of the macular region, it is the visual field representing the function of the whole retina. In addition to the simple and easy-to-use Amsler “s table, the traditional dynamic visual field examination method is the dynamic visual field examination method, and now the computer-controlled static quantitative perimetry is mostly used. In addition, the examination of stereopsis, which represents the highest level of vision, can be carried out by using stereoscopic view and stereoscopic picture of synoptophore, but for patients with low vision, there is often no stereopsis.