ABO Cornea and External Disease 2

Question 1

A soft contact lens wearer who rinses lenses with tap water has severe pain out of proportion to exam findings and radial perineuritis. What is the most likely organism?

Accepted Answer

Acanthamoeba species

Answer

Radial perineuritis with pain out of proportion in a contact lens wearer exposed to water is classic for early Acanthamoeba keratitis.

Question 2

Which genetic abnormality is most commonly associated with late-onset Fuchs endothelial corneal dystrophy?

Accepted Answer

CTG trinucleotide repeat expansion in TCF4

Answer

A CTG repeat expansion in an intron of TCF4 is found in most patients with late-onset Fuchs dystrophy.

Question 3

Corneal stromal deposits in granular corneal dystrophy type 1 stain most characteristically with which stain?

Accepted Answer

Masson trichrome

Answer

Granular dystrophy deposits are hyaline and stain bright red with Masson trichrome.

Question 4

Which corneal stromal dystrophy is inherited in an autosomal recessive pattern and is caused by CHST6 mutations?

Accepted Answer

Macular corneal dystrophy

Answer

Macular corneal dystrophy is autosomal recessive and results from abnormal keratan sulfate production caused by CHST6 mutations.

Question 5

An elderly patient has a painful peripheral corneal ulcer with an overhanging central edge and no scleritis or systemic disease after a full workup. What is the most likely diagnosis?

Accepted Answer

Mooren ulcer

Answer

Mooren ulcer is an idiopathic, painful peripheral ulcer with an undermined leading edge and no associated scleritis or systemic disease.

ABO - American Board of Ophthalmology Practice Test

ABO - American Board of Ophthalmology Practice Test

ABO Cornea and External Disease 2