Systemics Lecture I - Intro

What are the 3 types of fundus photos?

color, red-free, FAF

Fundus Color Photos

realistic, high-resolution, true color image

What is the best use for fundus color photos?

baseline, documentation, monitoring

Fundus Red-Free Photos

black and white or greenish images, enhanced, high contrast image

What are the advantages of fundus red-free photos?

improved contrast for retinal blood vessels, hemorrhages, retinal NFL, retinal surface changes

What is the best use for fundus red-free photos?

glaucoma, retinal NFL problems, retinal hemorrhages, micro aneurysms

Fundus Autofluorescence (FAF) Photos

enhanced imaging resulting from the excitation of lipofuscin

Lipofuscin

byproduct of photoreceptor outer segment metabolism and is present in the RPE

How does FAF work?

short wavelength blue light excited lipofuscin, causing it to emit a longer wavelength green-yellow light which is imaged

Hyperfluorescence

too much lipofuscin = metabolic stress/damage

Hypofluorescence

loss of RPE. cell death or blocked signal

Normal FAF Results

uniform grey retina, dark fovea, dark blood vessels, dark optic nerve

What are the best uses for FAF?

outer retinal disease including RPE, diseases with expected lipofuscin, optic nerve problems

Why is the choroid in particular at risk for melanoma?

fenestrated capillaries

What are the 3 types of fundus cameras in clinic?

Visucam, Cannon, Clarus

Visucam

color, red-free, blue, FAF, FA, ICGA

Cannon

color, general photos

Clarus

color, infrared, ultra-wide field, FAF

OCT (Optical Coherence Tomography)

non-invasive imaging technique using light waves to take a 3D cross-sectional image of the eye

OCT-A

visualization of movement within successive OCT scans, retinal and choroidal vasculature

What are the best uses for OCT-A?

diabetic retinopathy, capillary dropout, micro aneurysms, retinal perfusion/neovascularization

What are the advantages of OCT-A?

faster, non-invasive, imaging of all vascular layers separately

What are the disadvantages of OCT-A?

artifacts, need excellent operator, smaller retinal area compared to FA

What artery provides blood to the inner 2/3 of the retina?

CRA

What is the purpose of fluorescein angiography (FA)?

evaluating retinal and choroidal blood circulation in real time

What is the method of fluorescein angiography (FA)?

injecting NaFl dye into a vein and using a special camera to obtain timed photographs of the transit of dye through vessels in the eye

What are two possible findings with FA?

hypo or hyper fluorescence

Can FA detect vascular leakage?

yes

Can OCT-A detect vascular leakage?

no

What is the purpose of screening fields?

screen for disease risk, gross extent of peripheral vision

What is the purpose of threshold fields?

diagnose/monitor diseases (optic nerve, neurological)

What type of targets does screening fields use?

suprathreshold

What types of targets does threshold fields use?

threshold

What are 3 types of screening field machines?

FDT, Tempo, Humphrey

What are 3 types of threshold visual field machines?

Goldmann perimeter, Humphrey Field Analyzer, Octopus Perimeter

What type of visual field screening machine is binocular?

Tempo

Goldmann Perimeter

manual kinetic/static perimeter, maps visual field out to 90 degrees

Humphrey Field Analyzer

automated static threshold perimetry, gold standard

What are the most common test patterns for HFA?

30-2, 24-2, 10-2, 24-2c

HFA 30-2

original, 76 locations, 6 deg, central 30 deg

HFA 24-2

new standard for glaucoma, 54 locations, 6 deg, 52 within the central 24 deg plus 2 nasal points near 30 deg

HFA 10-2

central vision glaucoma, plaquenil screening, 68 locations, 3 deg apart, central 10 deg

HFA 24-2c

newest, glaucoma, hybrid of 24-2 and 10-2, includes most common abnormal central locations in glaucoma

SITA Standard HFA Test Algorithm

gold standard, most accurate

Octopus Perimeter

automated static and kinetic threshold perimetry, variable stimulus size, up to 90 deg, peripheral vision, children, visual field loss

Exophthalmometry

measures how far the globe protrudes from the bony orbit, from the canthus to the cornea

What are the best uses of exophthalmometry?

thyroid eye disease, orbital inflammation, suspected tumors

Amsler Grid

tests for central vision anomalies, scotomas (areas of no seeing), metamorphosis (distorted vision)

What are the best uses for the amsler grid?

macular disease (edema/degeneration), central visual disturbances

What is a color vision test best used for?

retinal diseases, optic nerve disease, inherited color vision defects

B-Scan Ultrasound

non-invasive, kinetic, real-time, 2D cross-sectional imaging of the eye and orbit, robust to media opacities

What are the best uses for B-scan ultrasound?

trauma, retinal tear/detach, tumors, intraocular foreign bodies