Rod-cone dystrophy is a group of inherited retinal disorders in which the rod photoreceptors, responsible for night and peripheral vision, are affected first, followed later by cone cells that support central and colour vision. It overlaps with conditions often termed retinitis pigmentosa.
Symptoms and Signs
Early symptoms typically include poor night vision and difficulty seeing in dim light, followed by progressive constriction of the visual field. Over time, central vision and colour discrimination can also decline as cone function becomes involved.
- Onset can range from childhood to adult life, depending on the specific gene
- Fundus examination may show pigmentary changes, vessel narrowing, and optic disc pallor
- Visual field testing demonstrates peripheral field loss
- Electroretinography usually shows reduced rod responses early on
Course and Management
The condition is usually slowly progressive and lifelong. Management focuses on optimising remaining vision, providing low vision aids, and supporting mobility and daily activities.
- Genetic testing can help define the subtype and inheritance pattern
- Family members may be offered counselling and, in some cases, carrier testing
- Regular review helps monitor progression and address treatable complications such as cataract or macular oedema
- Emerging gene and retinal therapies are being researched for some forms
