Presentation
Patients generally present in childhood or teenage years with symptoms of night blindness, and on examination of the retina, dark pigment changes may be seen, often described as bone spicules. Age of onset and visual prognosis are very variable. [retinauk.org.uk]
Clinical presentation COD presents with loss of central vision, photophobia and colour vision disturbance. Since cone function is usually initially normal, nystagmus is often absent. [bjo.bmj.com]
In stationary cone dystrophy, symptoms tend to remain stable and are usually present at birth or early childhood. In progressive cone dystrophy, symptoms slowly worsen over time. [rarediseases.org]
Presentation[edit] The most common symptoms of cone dystrophy are vision loss (age of onset ranging from the late teens to the sixties), sensitivity to bright lights, and poor color vision. Therefore, patients see better at dusk. [en.wikipedia.org]
Entire Body System
- Pallor
In addition to the retinal findings, temporal pallor of the optic disc is commonly observed. As expected, visual field testing in cone dystrophy usually reveals a central scotoma. [en.wikipedia.org]
Eyes
- Night Blindness
In this condition the rods are initially more affected than the cones giving problems with night blindness (nyctalopia). Later there are problems with the peripheral visual field, central vision and colour vision. [retinauk.org.uk]
Blindness X,XR,G 100 – CACNA2D4 Retinal Cone Dystrophy, Cone Rod Dystrophy, Congenital Stationary Night Blindness AR 99.64 7 of 7 CC2D2A Coach Syndrome, Joubert Syndrome, Meckel Syndrome AR 99.43 98 of 100 CCDC103 Primary Ciliary Dyskinesia AR 99.92 [igenomix.es]
Over time, affected individuals develop night blindness and a worsening of their peripheral vision, which can limit independent mobility. [medlineplus.gov]
- Scotoma
These features are typically followed by impaired color vision (dyschromatopsia), blind spots (scotomas) in the center of the visual field, and partial side (peripheral) vision loss. [medlineplus.gov]
As expected, visual field testing in cone dystrophy usually reveals a central scotoma. In cases with the typical bull's-eye appearance, there is often relative central sparing. [en.wikipedia.org]
(Gly1961Glu) in the homozygous state typically results in a milder phenotype,71 but can be associated with more severe disease when combined with other variants.72 Clinical assessment Symptomatic onset usually occurs in childhood with a central scotoma [bjo.bmj.com]
- Peripheral Vision Loss
These features are typically followed by impaired color vision (dyschromatopsia), blind spots (scotomas) in the center of the visual field, and partial side (peripheral) vision loss. [medlineplus.gov]
Skin
- Macula
Cones give us our colour vision and although they exist across the retina, they are densely clustered around the macula. Cone dystrophy stops the cones working, leading to loss of central and colour vision. [macularsociety.org]
However, the retinal pigment epithelium (RPE) rapidly becomes involved, leading to a retinal dystrophy primarily involving the macula. [en.wikipedia.org]
The highest concentration of cone cells is clustered in the oval-shaped, yellowish area near the center of the retina (macula). Cone cells are involved in the part of vision that enables a person to see fine details, read or recognize faces. [rarediseases.org]
(Arg172Trp)-associated CORD revealed increased cone spacing throughout the macula with corresponding loss of outer retinal structures on OCT.63 However, intrafamilial analysis of p. [bjo.bmj.com]
Workup
The inclusion of fluorescein angiography in the workup of these patients is important since it can help detect many of these characteristic ophthalmoscopic features. [en.wikipedia.org]
Treatment
Other treatment is symptomatic and supportive. [rarediseases.org]
Clinical trial of docosahexaenoic acid in patients with retinitis pigmentosa receiving vitamin A treatment. Arch. Ophthalmol. 2004;122(9):1297-305 25) Hassof RW, Fishman GA. [malattierare.regione.veneto.it]
Treatment We still do not clearly understand how cone dystrophies happen, or why people’s symptoms are so different. There is limited evidence that changes to your diet may slow sight loss caused by progressive cone dystrophies. [macularsociety.org]
[citation needed] Treatment[edit] Though there is no treatment for cone dystrophy, certain supplements may help in delaying the progression of the disease. [en.wikipedia.org]
Gene therapy encompasses multiple techniques, including gene replacement, gene editing and gene silencing, with treatment choice dependent on whether the associated sequence variant(s) leads to a loss or gain in function.97 Human treatment trials of gene [bjo.bmj.com]
Prognosis
Age of onset and visual prognosis are very variable. The condition can be inherited in different ways, recessive being most common. [retinauk.org.uk]
An accurate diagnosis using molecular genetics is an important step to facilitate genetic counselling, advice on prognosis and participation in anticipated clinical trials.89 Patients with specific forms of COD/CORD can be advised to adopt strategies [bjo.bmj.com]
Etiology
Clinical course, genetic etiology, and visual outcome in cone and cone-rod dystrophy. Ophthalmology. 2012 Apr;119(4):819-26. doi: 10.1016/j.ophtha.2011.10.011. Epub 2012 Jan 20. Citation on PubMed [medlineplus.gov]
Prevention
In GUCA1A-associated retinopathy, sleeping with the lights on is advocated by some clinicians for preventing accumulation of cGMP, which otherwise occurs at night and causes photoreceptor damage. [bjo.bmj.com]