OPT 526: Ocular Imaging & Biometry
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Questions and Answers

What is the purpose of fluorescein angiography?

To investigate the integrity of the retinal vasculature in retinochoroidal pathologies.

What is the first phase of fluorescein angiography?

  • Late recirculation
  • Pre-arterial (choroidal flush) (correct)
  • Arterial phase
  • Venous phase

    • In fluorescein angiography, how long does choroidal filling begin after injection?

  • 10-20 seconds (correct)
  • 30-40 seconds
  • 1-2 minutes
  • Immediately

    • Non-mydriatic cameras require pupil dilation for fundus photography.

    <p>False</p> Signup and view all the answers

    Name two indications for fluorescein angiography.

    <p>Macular degeneration and diabetic retinopathy.</p> Signup and view all the answers

    What phase is represented by mottled fluorescence of the choriocapillaris?

    <p>Pre-arterial (choroidal flush)</p> Signup and view all the answers

    What type of light do non-mydriatic cameras use?

    <p>Infrared light.</p> Signup and view all the answers

    What is the significance of optical filters in ocular photography?

    <p>They allow for light of different wavelengths to be used in imaging.</p> Signup and view all the answers

    What is the primary function of a condensing lens in ocular photography?

    <p>To focus images onto photographic film</p> Signup and view all the answers

    Which phase of fluorescein angiography shows temporary yellowing of the skin for most patients?

    <p>Late phase</p> Signup and view all the answers

    What is indicated by a classic petaloid pattern of hyperfluorescence on angiography?

    <p>Choroidal neovascularization</p> Signup and view all the answers

    What is the most frequently reported reaction to fluorescein angiography?

    <p>Nausea and emesis</p> Signup and view all the answers

    In patients with hypersensitivity to fluorescein dye, under what condition should fluorescein angiography be performed?

    <p>When it is vital</p> Signup and view all the answers

    Which of the following is a severe but rare reaction to fluorescein injection?

    <p>Fever</p> Signup and view all the answers

    How long should nursing mothers wait after fluorescein angiography before breastfeeding?

    <p>24-48 hours</p> Signup and view all the answers

    What alternative method is sometimes used instead of injecting fluorescein dye?

    <p>Orally administered fluorescein</p> Signup and view all the answers

    What is the incidence of death following the injection of fluorescein dye?

    <p>1 in 220,000</p> Signup and view all the answers

    During the late recirculation phase of fluorescein angiography, what is the main characteristic observed regarding blood vessels?

    <p>Arteries and veins are virtually devoid of fluorescein.</p> Signup and view all the answers

    What is the optimal time frame to observe the foveal avascular zone during fluorescein angiography?

    <p>20-25 seconds post-injection.</p> Signup and view all the answers

    In evaluating fluorescein angiography results, which aspect is essential during the initial interpretation phase?

    <p>Assess changes in fluorescence over time.</p> Signup and view all the answers

    What phenomenon causes focal hyperfluorescence in the temporal perifoveal region seen during fluorescein angiography?

    <p>Dilatation and leakage from perifoveal capillaries.</p> Signup and view all the answers

    What is the significance of identifying hypofluorescence during fluorescein angiography interpretation?

    <p>It may indicate the presence of subretinal blood.</p> Signup and view all the answers

    In fluorescein angiography, what does the term 'laminar flow' in the context of retinal veins refer to?

    <p>Layered flow with minimal turbulence in the retinal veins.</p> Signup and view all the answers

    Fluorescein angiography can help identify late leakage of fluorescein. Which phase is critical for observing this phenomenon?

    <p>Late recirculation phase.</p> Signup and view all the answers

    Which feature is essential when interpreting the results of fluorescein angiography?

    <p>Monitoring the distance from arm to eye.</p> Signup and view all the answers

    What does focal hyperfluorescence in an angiogram typically indicate regarding retinal pathology?

    <p>Potential areas of retinal vascular leakage</p> Signup and view all the answers

    During which phase of fluorescein angiography does the choroidal flush first become visible?

    <p>Pre-arterial phase</p> Signup and view all the answers

    What is a characteristic feature of the retinal veins observed during the venous phase of fluorescein angiography?

    <p>Disruption of laminar flow due to occlusions</p> Signup and view all the answers

    What is the primary role of the objective lens in ocular photography?

    <p>Create an aerial image of the retina</p> Signup and view all the answers

    What condition is indicated by a delay in choroidal filling time during fluorescein angiography?

    <p>Ocular ischemic syndrome</p> Signup and view all the answers

    Which type of camera allows for non-mydriatic fundus photography without pupil dilation?

    <p>Infrared fundus camera</p> Signup and view all the answers

    In fluorescein angiography, what signifies the start of the arterial phase?

    <p>Simultaneous branch filling</p> Signup and view all the answers

    What effectively happens at the onset of the late recirculation phase in fluorescein angiography?

    <p>Residual dye circulation continues to be visualized</p> Signup and view all the answers

    What is a key component of the illumination system used in ocular photography?

    <p>Flash lamp for exposure</p> Signup and view all the answers

    Which indication is NOT associated with fluorescein angiography?

    <p>Normal retinal examination</p> Signup and view all the answers

    Study Notes

    Retinal & Choroidal Imaging

    • Students will learn to describe various imaging procedures for the retina and choroid as well as interpret chorioretinal pathologies.
    • Colour fundus photography utilizes specially modified cameras to capture images of the ocular fundus, employing principles similar to indirect ophthalmoscopy.
    • Flash illumination is critical for photographic exposure in ocular imaging.
    • Illumination systems project light onto the retina through pupils using a condensing lens and mirrors, with flash lamps integrating for photography.
    • Optical filters in the illumination pathway allow capture of light at different wavelengths.
    • Non-mydriatic cameras facilitate fundus photography without dilating pupils, utilizing infrared light to reduce pupillary constriction.

    Fundus Cameras

    • Fundus cameras are described by their optical field of view, ranging from earlier models of 20-30 degrees to modern wide-field (>50 degrees) and ultra-wide-field (>100 degrees) cameras.

    Fluorescein Angiography (FA)

    • FA is essential for assessing the integrity of retinal vasculature in various retinochoroidal diseases.
    • Indications for FA include macular degeneration, central serous chorioretinopathy, cystoid macular edema, diabetic retinopathy, and unexplained vision loss, among others.
    • The FA test progresses through five phases: pre-arterial (choroidal flush), arterial, arteriovenous, venous, and late recirculation, starting with the injection of sodium fluorescein dye.
    • Choroidal filling occurs 10-20 seconds post-injection with an initial patchy pattern, resulting in generalized hyperfluorescence due to the fenestrated choroidal vascular system.

    Phases of Fluorescein Angiography

    • Choroidal Flush: Mottled fluorescence from the choriocapillaris, absent in the macular area due to pigment absorption.
    • Delayed Filling: This occurs in ocular ischemic syndrome (OIS).
    • Arterial Phase: Begins 1-2 seconds after choroidal filling; simultaneous filling of branches indicates normality. Delays signal potential abnormalities requiring further investigation.

    Learning Outcomes

    • Ability to describe imaging procedures for the retina and choroid.
    • Skill in interpreting chorioretinal pathologies from imaging results.

    Colour Fundus Ocular Photography

    • Utilizes specially modified cameras similar to indirect ophthalmoscopy for capturing fundus photographs.
    • Condensing lens fixed within camera housing, requiring flash illumination for exposure.
    • Illumination and imaging achieved through mirrors and optical filters to project different wavelengths of light onto the retina.
    • Digital cameras are now commonly used for capturing images.
    • Non-mydriatic cameras operate without pupil dilation, using infrared light to minimize pupil constriction.
    • Fundus cameras classified by optical field of view: older models 20°-30°; modern wide-field cameras >50°; ultra field >100°.

    Fluorescein Angiography (FA)

    • Key procedure for assessing retinal vasculature integrity in retinochoroidal conditions.
    • Indicative for various conditions such as macular degeneration, diabetic retinopathy, and unexplained vision loss.

    Stages of FA Test

    • Pre-arterial Phase: Begins post-injection of sodium fluorescein into the vein; choroidal filling starts within 10-20 seconds.
    • Arterial Phase: Follows choroidal filling, shows classic petaloid pattern of fluorescein in retinal branches 1-2 seconds later.
    • Venous Phase: Characterized by gradual dye recirculation; observed hyperfluorescence may indicate pathology.
    • Late Recirculation Phase: Lasts 7-20 minutes; identifies late leakage or dye accumulation.

    Key Stages of FA Interpretation

    • Choroidal Flush: Mottled fluorescence due to retinal pigment epithelium blockage; absent in macular area.
    • Arterial Phase Observation: Branches filling simultaneously leads to characteristic hyperfluorescence patterns.
    • Common Reactions: Nausea in 5% of cases, with serious reactions such as syncope reported in <1%.
    • Fluorescein Peak Concentration: Occurs 20-25 seconds post-injection; optimal for viewing lesions like foveal avascular zone.

    Risks and Side Effects

    • Minor reactions such as transient yellowing of skin are common; severe reactions are rare.
    • Safety precautions advise against FA in pregnant women; breastfeeding should be paused post-test.
    • Alternative oral fluorescein may be utilized for sensitivity cases.

    Interpretation Guidelines

    • Time monitoring for dye travel from arm to eye and major vascular fill times.
    • Identification of areas showing changes in hyperfluorescence or hypofluorescence in relation to baseline imaging.
    • Ensure findings correlate with clinical diagnosis for accurate evaluation.

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    Description

    This quiz focuses on ocular imaging and biometry related to retinal and choroidal assessments. By engaging with this content, students will learn about various imaging procedures and how to interpret related pathologies. Prepare to dive into techniques like colour fundus photography and ocular biometry.

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