Night Vision Loss

Question 1

Central findings in RP

Answer 1

CME
ONH drusen
PSC cats

Question 2

Findings in RP

Answer 2

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

Question 3

What is RP

Answer 3

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

Question 4

Symptoms of RP

Answer 4

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

Question 5

What can be used in dx of early RP

Answer 5

ERG

-the scotopic ERG is reduced, while the photopic ERG is relativel normal

Question 6

Gyrate atrophy

Answer 6

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.

Question 7

Appearance of gyrate atrophy

Answer 7

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

Question 8

Symptoms of gyrate atrophy

Answer 8

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

Question 9

Choroideremia

Answer 9

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

Question 10

Most common symptoms of choroidermia

Answer 10

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.

Question 11

Signs of choroidermia

Answer 11

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

Question 12

Fundus albipunctatus

Answer 12

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

Question 13

Inheritance of RP

Answer 13

Can be inherited or not
Can be assoacited with systemic diseases (ushers)
Damages the RPE and PR

Question 14

Systemic conditions assocaited with RP

Answer 14

Ushers
Abetalipoproteinemia 
Altroms disease
Cockaynes syndrome 
Kearnes Sayer Syndrome 
Laurence-Moon/Bardem-Biedl
Neuronal certificate lipofuscinosis

Question 15

Treatment of RP: adults

Answer 15

15,000 IU/day vitamin A

Question 16

Treatment of RP: kids

Answer 16

Vit A is controversial in children
The recommended dosage for kids is 5000 IU/day for 6 years old, and 10,000IU/day for 10 year olds. A pediatrician should be consulted prior ro starting vitamin A supplements

Question 17

RP and vitamin E

Answer 17

DO NOT rx vitamin E, as high doses (400IU/day) worsens RP

Question 18

The best treatment for patients with RP and functional vision loss are

Answer 18

Low vision aids, including tints and visual field enhancers

Question 19

Etiolgoy of gyrate atrophy

Answer 19

Deficiency in orthinine aminotransferase

Question 20

Etiology of choroidermia

Answer 20

Deficiency in rab geranylgeranyl transferase

Question 21

Etiology of fundus albipunctatus

Answer 21

AR congenital disorder caused by a mutation in the RDH5 gene that is necessary for proper function of the visual cycle

Question 22

ONH drusen in RP can cause

Answer 22

VF defects (they can cut the RNFL)

Question 23

Ocualr complciations of isotretinoin

Answer 23

Dryness 
Blepharokeratoconjunctivitis 
Eyelid edema
SPK
Nyctalopia 
Loss of color vision 
Psuedotumor cererbri
Cataracts

Question 24

Drugs that cause pseudotumor cerebri

Answer 24

CATS

• contraceptive
• accutane
• tetras
• synthroid
• steroids
• salicylic acid

Question 25

Digitalis ocular complications

Answer 25

BY color defects, retrobulbar optic neuritis, and entopic phenomenon NAK blocker

Question 26

What drugs can cause pigmentary retinopathy

Answer 26

Phennthiazine antipsychotic drugs (thioridazine and chlorpromazine)

Question 27

What can cause crystalline retinopathy

Answer 27

Tamoxifen