The cone cells are initially involved, as previously mentioned, and difficulty with the clarity of vision, colour vision problems and light sensitivity can be some of the earliest symptoms experienced. This is followed by a progressive loss of rod cells, which leads to night blindness and loss of side vision.
The age of onset, progression and severity of Conerod Dystrophies can vary greatly from one person to another, even among individuals w type of coneith the same rod dystrophy. It is therefore very difficult to predict what an individual’s vision will be like at a specific time in the future.
What is the Cause of Cone-Rod Dystrophy and how is it inherited?
Some forms of Cone-Rod dystrophy are inherited; other forms appear to occur spontaneously for no apparent reason (sporadically). Cone-Rod have many similarities to rod dystrophies Retinitis Pigmentosa, and like RP they can follow varied inheritance patterns, including autosomal dominant, autosomal recessive, and X-linked.
What treatments are available?
Maximising an individual’s remaining vision has remaining is a crucial first step to take. There are many new low vision aids, including telescopic and magnifying lenses, providing plenty of choice for users at all stages of sight loss. This technology has also removed many barriers to education and employment. There are, currently, no proven or effective cures for Cone-Rod Dystrophies.
However, scientists have identified more than 20 genes that can have mutations which cause these conditions. It is likely that many more mutations in many more genes will be identified in the coming years. Many future treatments will rely on identification of these gene defects.
This is the reason why Retina Australia considers the Australian Inherited Retinal Disease Register and DNA Bank, designed to identify the genes responsible for inherited retinal degenerations in Australian patients, including those with Cone-Rod Dystrophies, to be so important.
Despite the lack of current treatments for Cone-Rod Dystrophies, general eye check-ups are important. People with these conditions are still at risk for other kinds of eye problems that can affect the general population and may be treatable. Patients with Cone-Rod Dystrophies tend to develop cataracts at an earlier age than the overall population.
Regular visits to your eye doctor can also make you aware of current advances as we learn more about these conditions. A small clinical Phase I/II pilot has recently (mid 2018) been concluded at the National Institutes of Health Medical Centre in Maryland, USA, involving the direct administration of Interferon Gamma1b to the eye. No results are available as of yet.