Night Vision Loss Flashcards
Central findings in RP
CME
ONH drusen
PSC cats
Findings in RP
Waxy optic disc pallor Mid peripheral pigment clumping Attentuated arterioles Hyaline bodies within the ON PSC cataracts Keratoconnus
Additional findings
- macular changes
- myopia
- progressive contraction of the VF
What is RP
A generic term given to a group of hereditary condition characterized by progressive loss of PR and RPE function
-although rods and cones are both damaged, rod PR damage is more significant
There is tremendous variation in presentation, which correlated with the mode of inheritance
Symptoms of RP
Night blindness and peripheral vision loss (only in dim light in the early stages of the disease). Although the average age of dx is 9-19 years old, it often takes decades for symptoms to develop; ove 75% of patients are symptomatic by 30
What can be used in dx of early RP
ERG
-the scotopic ERG is reduced, while the photopic ERG is relativel normal
Gyrate atrophy
Very rare, bilateral, AR chorioretinal degeneration due to deficiency in the mitochondrial enzyme orthinine aminotransferase. Orthinine blood plasma levels will be high and may aid in the dx if the clinical picture is unclear.
Appearance of gyrate atrophy
Multiple, well defined scalloped areas of peripheral rchoroioretinal atrophy; in childhood, the lesions begin in the mid periphery and then coalesce to engulf most of the posterior pole, with the macula being spared until 40-70
Symptoms of gyrate atrophy
Prevalent by age 10
Nyctalopia
Decreased vision
Constricted visual fields
Decreased vision eventually occurs as a result of PSC cataracts, macular chorioretinal degeneration, or CME
May also be assoacited with high myopia and astigmatism
Choroideremia
Very rare condition characterized by diffuse and progressive atrophy of the choriocapillaris and overlying RPE. It is though to result from a deficiency in geranylgeranyl transferase, an ex year utilized in membrane metabolism
X linked, only males affected and all daughters are carriers, presents in 1st decade of life
Most common symptoms of choroidermia
Nyctalopia
Photophobia
Peripheral vision loss
Constricted visual fields
In males, night blindness occurs early in life and progresses to total night blindness within 10 years.
Signs of choroidermia
Diffuse, bilateral, mid-peripheral atrophy of the RPE and choriocapillaris that causes the appearance of a blond fundus
- the atrophy extends anteiror and posteriorly resulting in a scalloped appearance that is similar to gyrate atrophy
- as the atrophy worsens, the deep choroidal vessels become prominent and the underlying sclera becomes visible.
- the macula is commonly spared until the later stages of the disease; legal blindness occurs by 50-60
Fundus albipunctatus
AR congential disorder that causes STATIONARY night blindness
- numerous, small, yellow white dot like lesions at the level of the RPE; the lesions are in the mid periphery and spare the macula
- a variant of RP, retinitis albescens has a similar appearance to thus, but differs in that it resutls in the slow progression of night blindness
Inheritance of RP
Can be inherited or not
Can be assoacited with systemic diseases (ushers)
Damages the RPE and PR
Systemic conditions assocaited with RP
Ushers Abetalipoproteinemia Altroms disease Cockaynes syndrome Kearnes Sayer Syndrome Laurence-Moon/Bardem-Biedl Neuronal certificate lipofuscinosis
Treatment of RP: adults
15,000 IU/day vitamin A
