peg Retina 1&2 Flashcards
(19 cards)
What are the main functions of the retina?
Photoreception: Converts light into electrical signals.
Transmission: Sends visual information to the brain via the optic nerve.
Image processing: Initial processing of visual signals before they reach the visual cortex.
What are the layers of the retina?
Retinal Pigment Epithelium (RPE): Provides metabolic support to photoreceptors and absorbs scattered light.
Photoreceptor Layer: Contains rods (for low-light vision) and cones (for color and detailed vision).
Outer Nuclear Layer: Contains the nuclei of photoreceptors.
Inner Nuclear Layer: Contains bipolar cells and horizontal cells.
Ganglion Cell Layer: Contains ganglion cells, which transmit signals to the brain.
Optic Nerve Fibers: Carry signals from the retina to the brain.
What is the role of the macula and fovea?
The macula is the central part of the retina responsible for high-resolution vision.
The fovea is at the center of the macula and contains only cones, providing the sharpest vision for detailed tasks like reading and color perception.
How does the optic disc function in the retina?
The optic disc is where the ganglion cell axons converge to form the optic nerve.
It is the blind spot in the visual field, as it lacks photoreceptors.
What is the vitreous base and its significance?
The vitreous base is where the vitreous body attaches strongly to the ora serrata (boundary between retina and ciliary body).
It is the site of strongest vitreoretinal attachment and often the location of tractional retinal tears.
What are the clinical signs of retinal diseases?
Arteriosclerosis: Thickened blood vessel walls, causing AV nipping (venous compression by arteries).
Exudates: Yellow lesions from plasma leakage; associated with diabetic retinopathy and hypertension.
Cotton wool spots: White, fluffy lesions indicating retinal ischemia.
Neovascularization: Formation of new blood vessels due to retinal hypoxia or ischemia.
What are the causes and symptoms of macular degeneration?
Age-related macular degeneration (AMD) occurs due to degeneration of the macula.
Dry AMD: Characterized by drusen (yellow deposits) in the macula.
Wet AMD: Characterized by choroidal neovascularization leading to fluid leakage into the macula.
Symptoms include blurry central vision, difficulty reading, and distorted images (metamorphopsia).
What are retinal tears and how do they lead to retinal detachment?
Retinal tears occur when the retina is pulled by vitreous traction.
Tears allow fluid from the vitreous to accumulate between the retina and retinal layers, leading to rhegmatogenous retinal detachment.
What is retinal vein occlusion and its clinical signs?
Retinal vein occlusion occurs when a retinal vein is blocked, leading to venous dilation and tortuosity.
Branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO) can lead to hemorrhages, cotton wool spots, and macular edema.
What is retinitis pigmentosa and its symptoms?
Retinitis pigmentosa is a genetic disorder leading to progressive degeneration of photoreceptors.
Symptoms include night blindness, loss of peripheral vision, and a characteristic pattern of bone spicule pigmentation in the retina.
What is the significance of drusen in retinal health?
Drusen are yellow deposits in the retinal pigment epithelium (RPE), commonly seen in age-related macular degeneration (AMD).
Large drusen and soft drusen are risk factors for wet AMD.
What are the primary causes of retinal hemorrhages?
Diabetic retinopathy: Microaneurysms lead to small retinal hemorrhages.
Hypertensive retinopathy: High blood pressure causes arteriolar narrowing and retinal hemorrhages.
Retinal vein occlusion: Blocked veins result in extensive retinal hemorrhages.
How does diabetic retinopathy affect the retina?
In non-proliferative diabetic retinopathy: Microaneurysms, exudates, and retinal hemorrhages form.
In proliferative diabetic retinopathy: Neovascularization occurs, leading to risk of vitreous hemorrhage and retinal detachment.
What is the clinical significance of neovascularization in the retina?
Neovascularization is the formation of new, abnormal blood vessels in response to hypoxia or ischemia.
It can lead to leakage of fluid or hemorrhages into the retina and macula, causing vision loss.
What is posterior vitreous detachment (PVD)?
PVD occurs when the vitreous gel separates from the retina.
Common in aging, it can cause flashes of light and floaters. If not managed, it can lead to retinal tears or detachment.
How does hypertension affect the retina?
Hypertensive retinopathy is characterized by narrowing of retinal arteries, copper wiring, AV nicking, and cotton wool spots.
It can lead to retinal hemorrhages and optic disc swelling.
What is central retinal artery occlusion (CRAO) and its symptoms?
CRAO is a blockage of the central retinal artery, often due to embolism.
Symptoms include sudden monocular vision loss and a pale retina with a cherry-red spot at the macula.
What are cotton wool spots and their association with retinal health?
Cotton wool spots are small white lesions in the retina caused by axoplasmic flow stasis in the nerve fiber layer.
They are indicative of retinal ischemia and can be associated with diabetes, hypertension, and retinal vein occlusions.
What is choroiditis and its clinical signs?
Choroiditis is inflammation of the choroid, often leading to yellowish lesions and risk of scarring.
Common causes include infection, autoimmune diseases, and parasites.
