In primary care settings, the recommended assessment tools for evaluating visual impairment in adults focus on a combination of clinical examinations and functional tests to identify sight defects and visual field abnormalities. A standard sight test performed by an optometrist includes internal and external eye examinations to detect signs of injury, disease, or abnormality, which is essential for identifying visual impairment that cannot be corrected by standard glasses or contact lenses NICE NG81.
Specifically, for conditions such as glaucoma, which can lead to visual impairment, primary eye care professionals are advised to perform central visual field assessment using standard automated perimetry (either full threshold or supra-threshold), optic nerve assessment via stereoscopic slit lamp biomicroscopy (with pupil dilation if necessary), and intraocular pressure measurement using Goldmann-type applanation tonometry before referral NICE NG81. Peripheral anterior chamber configuration and depth assessments using gonioscopy or alternatives like the van Herick test or optical coherence tomography (OCT) are also recommended NICE NG81.
These tools collectively help detect visual field defects, optic nerve damage, and elevated intraocular pressure, which are critical markers of visual impairment and risk of sight loss. Repeat measurements of visual fields and intraocular pressure are advised to confirm findings before referral NICE NG81.
In addition to these clinical tools, functional assessments of visual acuity and patient-reported declines in visual function are important, especially in conditions like age-related macular degeneration, where optical coherence tomography (OCT) and fluorescein angiography (FFA) may be used to identify neovascular changes if visual acuity declines or visual function worsens despite stable OCT appearances NICE NG82.
Overall, primary care assessment of visual impairment integrates objective clinical tests (visual field testing, optic nerve imaging, intraocular pressure measurement) with functional vision evaluation and patient history to ensure early detection and appropriate referral NICE NG81,NICE NG82. This approach aligns with the broader epidemiological understanding that visual impairment prevalence increases with age, underscoring the importance of systematic assessment in older adults Zou et al. 2021.