age 1 of 209
Certified Diagnostic Ophthalmic Sonographer CDOS
exam ACTUAL QUESTIONS AND DETAILED ANSWERS
WITH RATIONALES LATEST UPDATE THIS YEAR.pdf
DOMAIN 1: OCULAR ANATOMY & PHYSIOLOGY (Questions 1-
60)
1. Which ocular layer contains the choroidal vasculature that
supplies the outer retina?
A) Sclera
B) Iris
C) Uvea
D) Retina
Answer: C
,age 2 of 209
Rationale: The uvea comprises the iris, ciliary body, and choroid;
the choroid provides the main blood supply to the outer retina.
The sclera is the outer fibrous layer; the retina is the innermost
neural layer.
Scenario: A 65-year-old patient with suspected choroidal
melanoma undergoes B-scan ultrasonography. The sonographer
notes a dome-shaped lesion originating from the choroidal
layer. Understanding that the choroid is part of the uveal tract
helps differentiate this from retinal pathology.
2. The average axial length of an adult human eye is closest to:
A) 16 mm
B) 22 mm
C) 24 mm
,age 3 of 209
D) 28 mm
Answer: C
Rationale: Normal adult axial length ranges from 22-24 mm; 24
mm is often cited as the average. Axial lengths > 26.5 mm are
associated with myopia and staphyloma formation.
3. Normal anterior chamber depth (ACD) in an adult ranges
from:
A) 1.5-2.0 mm
B) 2.0-2.5 mm
C) 2.5-3.5 mm
, age 4 of 209
D) 3.5-4.5 mm
Answer: C
Rationale: The normal adult anterior chamber depth ranges from
2.5-3.5 mm. Shallow anterior chamber (<2.5 mm) increases the
risk of angle-closure glaucoma.
4. Which of the following are components of the uveal tract?
(Select all that apply)
☐ A) Iris
☐ B) Ciliary body
☐ C) Choroid
Certified Diagnostic Ophthalmic Sonographer CDOS
exam ACTUAL QUESTIONS AND DETAILED ANSWERS
WITH RATIONALES LATEST UPDATE THIS YEAR.pdf
DOMAIN 1: OCULAR ANATOMY & PHYSIOLOGY (Questions 1-
60)
1. Which ocular layer contains the choroidal vasculature that
supplies the outer retina?
A) Sclera
B) Iris
C) Uvea
D) Retina
Answer: C
,age 2 of 209
Rationale: The uvea comprises the iris, ciliary body, and choroid;
the choroid provides the main blood supply to the outer retina.
The sclera is the outer fibrous layer; the retina is the innermost
neural layer.
Scenario: A 65-year-old patient with suspected choroidal
melanoma undergoes B-scan ultrasonography. The sonographer
notes a dome-shaped lesion originating from the choroidal
layer. Understanding that the choroid is part of the uveal tract
helps differentiate this from retinal pathology.
2. The average axial length of an adult human eye is closest to:
A) 16 mm
B) 22 mm
C) 24 mm
,age 3 of 209
D) 28 mm
Answer: C
Rationale: Normal adult axial length ranges from 22-24 mm; 24
mm is often cited as the average. Axial lengths > 26.5 mm are
associated with myopia and staphyloma formation.
3. Normal anterior chamber depth (ACD) in an adult ranges
from:
A) 1.5-2.0 mm
B) 2.0-2.5 mm
C) 2.5-3.5 mm
, age 4 of 209
D) 3.5-4.5 mm
Answer: C
Rationale: The normal adult anterior chamber depth ranges from
2.5-3.5 mm. Shallow anterior chamber (<2.5 mm) increases the
risk of angle-closure glaucoma.
4. Which of the following are components of the uveal tract?
(Select all that apply)
☐ A) Iris
☐ B) Ciliary body
☐ C) Choroid
