Vision and Ophthalmology Diagnostic Testing and Equipment 1 — Questions and Answers
Question 1: Optical coherence tomography (OCT) uses which type of light to generate cross-sectional retinal images?
- Fluorescent light
- Near-infrared light (Correct answer)
- X-rays
- Ultrasound
Correct answer: Near-infrared light
OCT uses near-infrared light interferometry to generate high-resolution cross-sectional images of retinal layers with micrometer-level resolution.
Question 2: The Goldmann applanation tonometer measures IOP by:
- Indenting the cornea with a plunger
- Flattening a known area of the cornea (3.06 mm diameter) (Correct answer)
- Shooting an air puff at the cornea
- Measuring the acoustic properties of the eye
Correct answer: Flattening a known area of the cornea (3.06 mm diameter)
Goldmann applanation tonometry measures the force required to flatten a standardized area (3.06 mm diameter) of the cornea, which correlates with IOP by the Imbert-Fick principle.
Question 3: Fluorescein angiography (FA) is primarily used to evaluate:
- Corneal topography
- Retinal and choroidal vasculature (Correct answer)
- Lens clarity
- Optic nerve fiber layer thickness
Correct answer: Retinal and choroidal vasculature
Fluorescein angiography involves IV injection of fluorescein dye to visualize retinal and choroidal circulation, detecting leakage, blockage, and neovascularization.
Question 4: Which visual field defect is associated with a pituitary adenoma compressing the optic chiasm?
- Ipsilateral monocular blindness
- Bitemporal hemianopia (Correct answer)
- Left homonymous hemianopia
- Central scotoma
Correct answer: Bitemporal hemianopia
Pituitary adenomas compress the crossing nasal fibers at the optic chiasm, causing bitemporal hemianopia (loss of both temporal fields).
Question 5: A-scan ultrasonography in ophthalmology is primarily used for:
- Measuring axial length for IOL calculations (Correct answer)
- Imaging the optic nerve
- Detecting retinal tears
- Measuring corneal thickness
Correct answer: Measuring axial length for IOL calculations
A-scan ultrasonography measures the axial length of the eye, which is essential for calculating intraocular lens (IOL) power before cataract surgery.
Question 6: Corneal topography measures which property of the cornea?
- Thickness at all points
- Curvature across the corneal surface (Correct answer)
- Endothelial cell count
- Transmittance of UV light
Correct answer: Curvature across the corneal surface
Corneal topography (videokeratography) maps the curvature of the anterior corneal surface using Placido disc reflection patterns or Scheimpflug imaging.
Vision and Ophthalmology Diagnostic Testing and Equipment 1
Optical coherence tomography (OCT) uses which type of light to generate cross-sectional retinal images?