OCT Imaging in Retinal Conditions Quiz

A type of optical coherence tomography (OCT) that provides detailed imaging of the macula – the central part of the retina responsible for sharp, central vision. It allows clinicians to visualize the retinal layers and identify various macular conditions.

A reduction in the thickness of the retinal nerve fiber layer (RNFL), which is a layer of nerve fibers that carry information from the retina to the brain. It can be a sign of glaucoma or other eye conditions.

Four key structures within the retina that reflect light strongly and are essential for good visual acuity. These include the retinal pigment epithelium (RPE), interdigitation zone (IZ), ellipsoid zone (EZ), and external limiting membrane (ELM).

A type of OCT specifically used to image the optic nerve head (ONH), which is the area where the optic nerve connects to the eye. It helps diagnose and evaluate conditions like glaucoma by analyzing the ONH structure and RNFL thickness.

A type of ultrasound that sends sound waves into the eye and measures the time it takes for the waves to return. This creates a one-dimensional image of the eye's internal structures, allowing for evaluation of their size, shape, and reflectivity.

A type of ultrasound that creates a two-dimensional image of the eye's internal structures. It's particularly useful when the interior of the eye can't be seen clearly due to obstructions like cataracts or vitreous hemorrhage.

FA stages describe the progressive filling and emptying of the retinal and choroidal vasculature with fluorescein dye. Stages include: Pre-arterial, Arterial, Capillary, Venous (early, mid, late), and Late. Each stage provides insights into the blood flow dynamics and potential abnormalities.

The first stage of FA where the choroidal circulation is filled with fluorescein dye but the dye hasn't reached the retinal arteries. This phase is very fast, lasting only a fraction of a second.

The second stage of FA when dye begins to fill the retinal arteries. The central retinal artery (CRA) appears white due to fluorescein, while the central retinal vein (CRV) remains black.

The stage where the retinal arteries and capillaries are completely filled with fluorescein dye. Retinal capillaries become visible, especially around the optic nerve head (ONH) and foveal avascular zone (FAZ).

The stage where the veins begin to fill with fluorescein dye. This phase is subdivided into early, mid, and late stages. The early venous stage is also called the arterio-venous stage, where the arteries and capillaries are filled and there is lamellar flow in the veins. The mid-stage involves nearly complete vein filling, and the late stage signifies complete vein filling and artery emptying.

The final stage of FA, occurring 7-15 minutes after injection, where fluorescein is gradually eliminated from the retinal and choroidal vasculature. Late staining of the optic disc is normal, while other areas of late hyperfluorescence may indicate pathology.

Autofluorescence (AF) imaging uses a low-energy laser to stimulate lipofuscin in the retinal pigment epithelium (RPE). A barrier filter is used to isolate the RPE autofluorescence, resulting in a single monochromatic image with high contrast. Hypo- and hyperfluorescent signals can be analyzed to diagnose various retinal diseases.

Hypofluorescent areas in AF images indicate a lower than normal autofluorescence signal. This can be observed in RPE atrophy, fresh hemorrhages, exudative lesions, dense hyperpigmentation, and hard drusen.

Hyperfluorescent areas in AF images indicate a stronger than normal autofluorescence signal. This can occur in yellow lesions with high lipofuscin concentration in the RPE, such as Best's and Stargardt's disease, older hemorrhages, and soft drusen.

Evaluates the patency of the nasolacrimal duct by assessing the presence of fluorescein in the nasal cavity after instilling saline into the conjunctival sac.

Indicates a patent nasolacrimal duct, as fluorescein is detected in the nasal cavity and/or the patient can feel it going down their throat.

Suggests a blocked nasolacrimal duct, as fluorescein is not recovered and/or the patient doesn't feel saline in their throat.

Measures tear production by assessing the amount of moisture absorbed by a filter paper strip placed at the lateral canthus of the lower eyelid.

It primarily evaluates the aqueous portion of the tear film, which is a major component of tear production.

The process of removing a foreign object from the eye, typically involving irrigation, tweezers, or specialized instruments.

Paralysis of the ciliary muscle of the eye, leading to dilation of the pupil and relaxation of the lens.

Infections that occur as a complication of a prior injury or condition, like after a corneal foreign body.

A condition characterized by multiple small, superficial lesions on the cornea, often caused by dryness, infection, or irritation.

Bleeding under the conjunctiva, the thin membrane covering the white part of the eye, often appearing as a red patch.

A wound that penetrates the eye's outer layers, potentially damaging internal structures.

Antibiotics that target a wide range of bacteria, often used for initial treatment of infections of unknown origin.

A patch applied to the eye to provide pressure, reduce pain, and promote healing after eye surgery or injury.

A medication that causes cycloplegia and is often used to dilate the pupil and relax the ciliary muscle for eye exams.

A thin membrane derived from the amniotic sac, used in ophthalmology to promote healing and reduce scarring after corneal injury or surgery.

A technique that uses backlighting to illuminate structures within the eye, allowing for visualization of details often obscured by direct light.

A prism-shaped structure used in ophthalmological microscopes to direct light and create a specific angle for visualization.

A type of reflection that focuses light off a smooth surface, allowing for the evaluation of endothelial cells in the cornea or epithelial cells on the lens.

Cells lining the inner surface of the cornea, responsible for maintaining corneal transparency.

Cells covering the outer surface of the lens, responsible for maintaining lens clarity.

A technique that uses a parallelepiped at the limbus to scatter light internally throughout the cornea, revealing abnormalities.

A condition where the central cornea becomes opaque, reducing vision. It can be observed with the naked eye using sclerotic scatter.

Specular reflection is the best technique to evaluate endothelial cells. It uses a parallelepiped angled at 60°-90° with high magnification and illumination.

During specular reflection, slowly advance the parallelepiped across the cornea until a ghostlike image (pale yellow) is seen, along with a bright image of the filament.

To observe a patient with CCC, the oculars (eyepiece) are placed directly opposite the light source, allowing for visual confirmation with sclerotic scatter.