In Part 4 of LV Corner, Abi Crutcher FBDO CL Prof. Cert. LV. looks at the diseases that cause visual impairment…
Macular degeneration
People with age-related macular degeneration (AMD) often experience central distortion in their vision, in addition to reduced visual acuity (VA). They may also have scotomas, with patches of their vision missing completely, often centrally, which can cause significant difficulties. Near vision is often difficult, as it is impossible to read words when looking directly at them. Colour vision and contrast sensitivity are also usually affected.
Glaucoma
Glaucoma can cause reduced contrast sensitivity, often before any reduction in VA is noticed. The peripheral field of vision also contracts. People with glaucoma often experience difficulties in low light conditions.
Cataract
People with cataract can experience difficulty reading, especially in low light conditions, and often have significant difficulties with glare and reduced contrast sensitivity.
Retinitis pigmentosa
Peripheral visual field loss is a key feature of retinitis pigmentosa (RP), with VA remaining good until the later stages of the disease, unless macula oedema is present which can cause central distortion. Night vision difficulties, often noticed before any visual field loss, can be a significant problem for
people with RP, as well as difficulties with changing light levels such as going from light to dark environments and vice versa.
Diabetic retinopathy
Diabetic retinopathy causes a varied range of problems, which may vary from day to day. The visual field may be affected centrally or peripherally, and there may be large floaters or central distortion present. Contrast sensitivity and colour vision are often affected, although patients may retain a good VA. Near vision difficulties are often reported.
Other causes of visual impairment
Other diseases and factors can lead to visual impairment such as corneal disease and injury, brain and other neurological disease, as well as more common eye conditions seen in practice such as amblyopia and strabismus.
Next month, we will look at low vision assessments.
Abi Crutcher is an extended services contact lens optician with a professional certificate in low vision. In addition to working in practice, Abi represents dispensing opticians on her regional optical committee and, through that, on the Welsh Optometric Committee. She represents optometry on her local primary care cluster committee – and is ABDO’s regional lead in Wales.