ABO Retina and Vitreous 2

Question 1

A 10-year-old boy has bilateral spoke-wheel foveal schisis and an electronegative ERG. Which gene is most likely mutated?

Accepted Answer

RS1

Answer

X-linked juvenile retinoschisis is caused by RS1 mutations and classically shows foveal schisis with a reduced b-wave (negative ERG).

Question 2

Which electrophysiologic finding is most characteristic of Best vitelliform macular dystrophy?

Accepted Answer

Arden ratio below 1.5 on EOG with a normal full-field ERG

Answer

Best disease shows a markedly abnormal EOG (light-peak/dark-trough ratio usually below 1.5) with a normal full-field ERG.

Question 3

A patient on hydroxychloroquine for 6 years has parafoveal ellipsoid zone loss on OCT. Per AAO guidance, what is the recommended maximum daily dose to minimize toxicity risk?

Accepted Answer

5.0 mg/kg real body weight

Answer

The 2016 AAO recommendation is 5.0 mg/kg real body weight per day or less for hydroxychloroquine.

Question 4

In Asian patients with hydroxychloroquine toxicity, where is retinal damage most often first detected?

Accepted Answer

Pericentral region beyond the arcades

Answer

Asian patients frequently show a pericentral pattern of toxicity, so screening should include wider fields such as 24-2 or 30-2.

Question 5

Which ERG pattern is classic for melanoma-associated retinopathy (MAR)?

Accepted Answer

Electronegative ERG resembling complete CSNB

Answer

MAR antibodies target ON-bipolar cells, producing a negative ERG similar to complete congenital stationary night blindness.

ABO - American Board of Ophthalmology Practice Test

ABO - American Board of Ophthalmology Practice Test

ABO Retina and Vitreous 2