Cone Dystrophies Flashcards
cone dystrophies - ERG
photopic responses are subnormal or non-recordable and flicker fusion frequency is reduced, but rod responses are preserved until late
cone dystrophies - EOG
normal to subnormal
cone dystrophies - DA
the cone segment is abnormal; the rod segment is initially normal, but may become subnormal later
cone dystrophies - Colour vision
severe deuteron–tritan defect out of proportion to visual acuity
cone dystrophies - Fluorescein angiography
round hyperfluorescent window defect with a hypofluorescent centre
most common macular dystrophy
Stargardt disease
Stargardt disease - genetics
AR ABCA4
Stargardt disease - appearance
The macula may initially be normal or show non-specific mottling, progressing to an oval ‘snail slime’ or ‘beaten-bronze’ appearance and subsequently to geographic atrophy that may tend to a bull’s-eye configuration. A small proportion CNV. ○ Numerous yellow–white round, oval or pisciform (fish-shaped) lesions at the level of the RPE; these may be confined to the posterior pole or extend to the mid-periphery
Stargardt disease - FAF
hyperautofluorescent flecks and macular hypoautofluorescence
Stargardt disease - FA
The classic feature is a ‘dark choroid’ due to masking of background choroidal fluorescence by diffuse RPE abnormality; the macula shows mixed hyper- and hypofluorescence. Fresh flecks show early hypofluorescence due to blockage, and late hyperfluorescence due to staining; old flecks show RPE window defects
Stargardt disease - ICGA
hypofluorescent spots, often more numerous than seen clinically
Bietti crystalline corneoretinal dystrophy - genetics
AR
Bietti crystalline corneoretinal dystrophy - appearance
Numerous fine yellow–white crystals scattered throughout the posterior fundus are followed by localized atrophy of the RPE and choriocapillaris at the macula, expand to periphery
Bietti crystalline corneoretinal dystrophy - FA
characteristic large hypofluorescent patches corresponding to choriocapillaris loss, with intact overlying retinal vessels; the patches become confluent over time
Alport syndrome - genetics
XLR, IV collagen
Alport syndrome - features
chronic renal failure, sensorineural deafness, yellowish punctate flecks in the perimacular area. Anterior lenticonus and posterior polymorphous corneal dystrophy. prognosis good
Alport syndrome - ERG
normal
Congenital stationary night blindness - With an abnormal fundus appearance
Oguchi disease, Fundus albipunctatus
Fundus albipunctatus - features
multitude of subtle, tiny yellow– white spots at the posterior pole, sparing the fovea. In contrast to retinitis punctata albescens, the retinal blood vessels, optic disc, peripheral fields and visual acuity are believed to remain normal
Rod monochromatism - other name + genetics
complete achromatopsia AR
complete achromatopsia - other name + genetics
Rod monochromatism AR
Blue cone monochromatism - other name + genetics
incomplete achromatopsia XLR
incomplete achromatopsia - other name + genetics
Blue cone monochromatism XLR
Rod monochromatism (complete achromatopsia) - AR
visual acuity is poor, typically 6/60; there is congenital nystagmus and photophobia. The photopic (cone) ERG is abnormal and the scotopic may also be subnormal.
