MedGen

Achromatopsia is characterized by reduced visual acuity, pendular nystagmus, increased sensitivity to light (photophobia), a small central scotoma, eccentric fixation, and reduced or complete loss of color discrimination. All individuals with achromatopsia (achromats) have impaired color discrimination along all three axes of color vision corresponding to the three cone classes: the protan or long-wavelength-sensitive cone axis (red), the deutan or middle-wavelength-sensitive cone axis (green), and the tritan or short-wavelength-sensitive cone axis (blue). Most individuals have complete achromatopsia, with total lack of function of all three types of cones. Rarely, individuals have incomplete achromatopsia, in which one or more cone types may be partially functioning. The manifestations are similar to those of individuals with complete achromatopsia, but generally less severe. Hyperopia is common in achromatopsia. Nystagmus develops during the first few weeks after birth followed by increased sensitivity to bright light. Best visual acuity varies with severity of the disease; it is 20/200 or less in complete achromatopsia and may be as high as 20/80 in incomplete achromatopsia. Visual acuity is usually stable over time; both nystagmus and sensitivity to bright light may improve slightly. Although the fundus is usually normal, macular changes (which may show early signs of progression) and vessel narrowing may be present in some affected individuals. Defects in the macula are visible on optical coherence tomography. [from GeneReviews]

A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele). [from HPO]

Blindness is the condition of lacking visual perception defined as a profound reduction in visual perception. On the 6m visual acuity scale, blindness is defined as less than 3/60. On the 20ft visual acuity scale, blindness is defined as less than 20/400. On the decimal visual acuity scale, blindness is defined as less than 0.05. Blindness is typically characterized by a visual field of no greater than 10 degrees in radius around central fixation. [from HPO]

Excessive sensitivity to light with the sensation of discomfort or pain in the eyes due to exposure to bright light. [from HPO]

The absence of or defect in the perception of colors. [from MONDO]

Retinal dystrophy is an abnormality of the retina associated with a hereditary process. Retinal dystrophies are defined by their predominantly monogenic inheritance and they are frequently associated with loss or dysfunction of photoreceptor cells as a primary or secondary event. [from HPO]

A form of colorblindness in which only two of the three fundamental colors can be distinguished due to a lack of one of the retinal cone pigments. [from HPO]

Diminished clarity of vision. [from NCI]

Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms. [from HPO]

A rare retinal dystrophy characterized by photophobia, progressive loss of visual acuity, nystagmus, visual field abnormalities, abnormal color vision, and psychophysical and electrophysiological evidence of abnormal cone function. Progressive cone dystrophy usually presents in childhood or early adult life, and patients tend to develop rod photoreceptor dysfunction in later life. [from ORDO]

A visual anomaly in which images appear distorted. A grid of straight lines appears wavy and parts of the grid may appear blank. [from HPO]

A visual defect characterized by the inability to see as clearly in bright light as in dim light. The word hemeralopia literally means day blindness. [from HPO]

Transmission of gene defects or chromosomal aberrations/abnormalities which are expressed in extreme variation in the structure or function of the eye. These may be evident at birth, but may be manifested later with progression of the disorder. [from MeSH]

Any impairment to the vision. [from NCI]

The magnitude of INBREEDING in humans. [from MeSH]

An anomaly in the ability to discriminate between or recognize colors. [from HPO]

Non-heritable difficulty in distinguishing colors. [from NCI]

Achromatopsia is characterized by reduced visual acuity, pendular nystagmus, increased sensitivity to light (photophobia), a small central scotoma, eccentric fixation, and reduced or complete loss of color discrimination. All individuals with achromatopsia (achromats) have impaired color discrimination along all three axes of color vision corresponding to the three cone classes: the protan or long-wavelength-sensitive cone axis (red), the deutan or middle-wavelength-sensitive cone axis (green), and the tritan or short-wavelength-sensitive cone axis (blue). Most individuals have complete achromatopsia, with total lack of function of all three types of cones. Rarely, individuals have incomplete achromatopsia, in which one or more cone types may be partially functioning. The manifestations are similar to those of individuals with complete achromatopsia, but generally less severe. Hyperopia is common in achromatopsia. Nystagmus develops during the first few weeks after birth followed by increased sensitivity to bright light. Best visual acuity varies with severity of the disease; it is 20/200 or less in complete achromatopsia and may be as high as 20/80 in incomplete achromatopsia. Visual acuity is usually stable over time; both nystagmus and sensitivity to bright light may improve slightly. Although the fundus is usually normal, macular changes (which may show early signs of progression) and vessel narrowing may be present in some affected individuals. Defects in the macula are visible on optical coherence tomography. [from GeneReviews]