OCT Anatomy
Which retinal layer contains the photoreceptor inner and outer segments?
The photoreceptor layer (including the ellipsoid zone).
What does OCT stand for?
Optical Coherence Tomography.
Which instrument is commonly used to measure intraocular pressure by flattening the cornea?
Goldmann applanation tonometer.
What is the unit used to measure refractive power?
Diopter
What does IOP stand for?
Intraocular pressure
What is the foveal pit, and why does it appear as a depression on OCT?
The central macular depression caused by displacement of inner retinal layers.
What is a B-scan in OCT?
A cross-sectional image composed of multiple A-scans.
What is the purpose of the swinging flashlight test?
To detect a relative afferent pupillary defect (RAPD).
Which lens corrects simple myopia?
A minus (concave/diverging) lens.
What does "md" represent on an automated visual field report?
Mean Deviation
Which retinal layer contains ganglion cell axons?
Retinal nerve fiber layer (RNFL).
Name two common causes of OCT image artifacts.
Examples: eye motion, blinking, poor fixation, segmentation errors, or media opacity.
Which cover test detects a tropia, and which detects a phoria?
Cover-uncover detects tropia; alternate cover breaks fusion and reveals total deviation including phoria.
What is the spherical equivalent of +2.00 −1.00 × 180?
+1.50 D.
What is the difference between fixation losses and false-positive responses in perimetry?
Fixation losses suggest reduced fixation reliability; false positives occur when the patient responds without a valid stimulus.
Both affect confidence in test interpretation.
Which highly reflective OCT band is associated with the retinal pigment epithelium?
The RPE/Bruch's membrane complex.
How does spectral-domain OCT differ from swept-source OCT?
Spectral-domain uses a broadband light source and spectrometer; swept-source uses a rapidly tunable wavelength laser and a detector.
What is the appropriate action when Goldmann mires are irregular and distorted?
Check for tear-film irregularity, staining adequacy and technique; repeat the measurement after correcting the issue.
Distorted semicircles can make the endpoint unreliable.
Transpose −2.00 +1.50 × 090 into minus-cylinder notation.
−0.50 −1.50 × 180.
What classic visual field defect respects the horizontal meridian and is associated with glaucoma?
A nasal step (or arcuate defect).
What is the distinction between intraretinal and subretinal fluid on OCT?
Intraretinal fluid accumulates within retinal layers; subretinal fluid accumulates between the neurosensory retina and RPE.
What is a segmentation error, and how can it affect RNFL or macular thickness measurements?
Incorrect automated identification of anatomical boundaries, resulting in inaccurate thickness values.
In retinoscopy, what does neutralization mean?
The reflex shows no apparent directional movement when the correct lens power is introduced at the working distance.
Subtract working-distance dioptric power to determine distance refractive error.
A spectacle prescription is −3.00 −2.00 × 180. What is the power in the 90-degree meridian?
−5.00 D.
How would you interpret progressive RNFL thinning accompanied by repeatable corresponding visual field loss?
As concerning for glaucomatous structural and functional progression, after confirming test quality and clinical correlation.
Review OCT segmentation, signal quality, field reliability and longitudinal trends.