retina Flashcards
Your 67 year-old male patient presents with flame-shaped and dot-blot hemorrhages in the inferior retina of his left eye secondary to a branch retinal vein occlusion. Which of the following statements best describes the MOST common etiology of this ocular condition?
Significantly elevated intraocular pressure leading to compression of a retinal vein and subsequent venous occlusion
Thickening of an overlying retinal arteriole compressing the vein, resulting in a focal venous occlusion
Intimal thickening of a vein resulting in progressive narrowing of the central lumen and eventual venous occlusion
A migrating emboli, most commonly from an atheromatous plaque, becomes lodged at a vessel bifurcation, leading to the occlusion of a retinal vein
Thickening of an overlying retinal arteriole compressing the vein, resulting in a focal venous occlusion
The presence of which of the following retinal characteristics will result in a corresponding area of hyperfluorescence during fluorescein angiography?
Hard exudates Lipofuscin Pigment epithelial detachment Congenital hypertrophy of the RPE Choroidal nevus Intraretinal hemorrhage
PED
Areas of hyperfluorescence that appear during fluorescein angiography occur due to either an absolute increase in the amount of fluorescein in the retinal tissues or as a result of enhanced visualization of a normal quantity of fluorescein in the fundus. Conditions that can lead to hyperfluorescence include leakage of dye from abnormal choroidal vasculature (such as a choroidal neovascular membrane), abnormal retinal neovascularization (as in proliferative diabetic retinopathy), or breakdown of the inner blood-retinal barrier (cystoid macular edema). Hyperflourescence also occurs as a result of pooling of fluorescein secondary to breakdown of the outer blood-retinal barrier in such conditions as central serous retinopathy and pigment epithelial detachments. A transmission (or window) defect caused by an absence or atrophy of the RPE results in unmasking of normal background choroidal fluorescence, leading to the appearance of hyperfluorescent areas.
Hypofluorescent regions on fluorescein angiography are due to either obstruction (masking) of normal density of fluorescein in the retinal tissue (blood, hard exudates, increased density of RPE, or choroidal nevi) or inadequate perfusion of the retinal tissue (vascular occlusion, or loss of the vascular bed).
Which 3 of the following types of retinal cells undergo a GRADED potential (vs. an action potential)? (Select 3)
Horizontal cells Photoreceptor cells Amacrine cells Ganglion cells Bipolar cells Which 3 of the following types of retinal cells undergo a GRADED potential (vs. an action potential)? (Select 3)
Horizontal cells Photoreceptor cells Amacrine cells Ganglion cells Bipolar cells
H, Photore, Bi
he C-wave seen in an electroretinogram is created by which cells?
Bipolar cells The photoreceptors Ganglion cells The retinal pigment epithelial cells = Mueller cells
The retinal pigment epithelial cells
Electroretinograms (ERGs) are created by electric currents across the eye (the cornea is positive relative to the retinal pigment epithelium). They are a summation of the different electrical responses of retinal cells to stimuli. The A-wave of the ERG is formed by the photoreceptors. The B-wave occurs due to the responses from bipolar and Mueller cells. The C-wave is created by responses from retinal pigment epithelial cells, and the D-wave is attributable to activity of the OFF bipolar cells. The C-wave and the D-wave are not used clinically very often because they are susceptible to being obscured by blinking of the eye. It is also noteworthy that oscillations seen in the B-wave are due to responses of the amacrine cells.
Which retinal layer serves as an interface between the retina and the vitreous?
The retinal pigment epithelium
The nerve fiber layer
The external limiting membrane
The internal limiting membrane
ILM
Shining a small spot of light onto the center of the receptive field of a retinal ganglion cell results in an increased frequency of action potentials; however, increasing the size of the light causes a decrease in the frequency of action potentials. Why does this occur?
Due to the fact that ganglion cells have receptive fields that are center-surround
The retinal dark current, if overly exposed, results in spatial antagonism by cone cells
Rhodopsin responds preferentially to small sources of light allowing for high spatial resolution
Because activation of rods causes the inhibition of ganglion cells
Due to the fact that ganglion cells have receptive fields that are center-surround
remember joana’s pics
The majority of ganglion cells possess center-surround receptive fields and therefore exhibit lateral inhibition. This property serves to increase spatial resolution. The receptive fields can be either center on or center off. The receptive field appears like a donut, with the center being excited by light and the surrounding annulus inhibited by light or vice versa. Increasing the size of the stimulus causes summation of both parts of the receptive fields, resulting in a greater reduction in the frequency of action potentials than if the center were to be stimulated alone.
At which location in the eye is the most common site of occurrence for a branch retinal vein occlusion (BRVO)?
Inferior temporal
Superior nasal
Inferior nasal
Superior temporal
Superior temporal
Branch retinal vein occlusions (BRVO) are the most common type of vascular occlusion encountered in clinic. Common associations include, but are not limited to: hypertension, diabetes, and congestive heart failure. The superior temporal vein is the most frequently involved, followed by the inferior temporal vein. The nasal quadrants are rarely involved. The pathogenesis of a BRVO results from compression of the vein by the overlying artery impeding blood flow return. The blood accumulates and eventually leaks out of the vessel, resulting in retinal hemorrhages. Some researchers have suggested that the superior temporal quadrant of the eye has the greatest amount of arterial/vein crossing junctions, and therefore possesses a higher likelihood of involvement. Visual acuity may be compromised, depending upon the presence of macular involvement. Greater amounts of ischemia increase the chances of complications such as neovascularization of the retina and rubeosis iridis.
Which of the following correctly lists the layers of the retina beginning with the retinal pigment epithelium and moving anteriorly?
Retinal pigment epithelium, outer nuclear layer, external limiting membrane, photoreceptor layer, outer plexiform layer, inner plexiform layer, inner nuclear layer, nerve fiber layer, ganglion cell layer, internal limiting membrane
Retinal pigment epithelium, photoreceptor layer, outer nuclear layer, external limiting membrane, outer plexiform layer, inner plexiform layer, inner nuclear layer, ganglion cell layer, nerve fiber layer, internal limiting membrane
Retinal pigment epithelium, external limiting membrane, outer nuclear layer, photoreceptor layer, outer plexiform layer, inner nuclear layer, inner plexiform layer, nerve fiber layer, ganglion cell layer, internal limiting membrane
Retinal pigment epithelium, photoreceptor layer, external limiting membrane, outer nuclear layer, outer plexiform layer, inner nuclear layer, inner plexiform layer, ganglion cell layer, nerve fiber layer, internal limiting membrane Your Answer
Retinal pigment epithelium, photoreceptor layer, external limiting membrane, outer nuclear layer, outer plexiform layer, inner nuclear layer, inner plexiform layer, ganglion cell layer, nerve fiber layer, internal limiting membrane Your Answer
he internal limiting membrane of the retina is formed by a combination of glial cell processes and which other cell type?
Muller cells
Horizontal cells
Bipolar cells
Amacrine cells
muller
The internal limiting membrane is formed by radial feet processes of Muller cells along with other glial cell constituents. Muller cell processes extend throughout the length of the retina except for the retinal pigment epithelium. Their cell bodies are found in the inner nuclear layer. Muller cells, along with segments of the photoreceptors, create tight junctions and serve to form the external limiting membrane.
Which of the following ocular conditions is NOT considered a “white dot syndrome?”
Birdshot retinochoroidopathy
Polypoidal choroidal vasculopathy
Serpiginous choroidopathy
Acute posterior multifocal placoid pigment epitheliopathy (APMPPE)
Polypoidal choroidal vasculopathy
White dot syndromes (also known as primary idiopathic inflammatory choriocapillaropathies) are ocular inflammatory conditions that are characterized by the presence of white dots on the fundus. The most common visual symptoms of patients presenting with these diseases include blurred vision and visual field loss. The exact etiology of these ocular conditions is unknown; however, some investigators believe there to be a connection with bacterial and viral infections, genetic predispositions, and/or autoimmune associations. Classically recognized white dot syndromes include: acute posterior multifocal placoid pigment epitheliopathy (APMPPE), birdshot retinochoroidopathy, multiple evanescent white dot syndrome (MEWDS), serpiginous choroiditis, punctate inner choroidopathy (PIC), and multifocal choroiditis with panuveitis (MCP).
Polypoidal choroidal vasculopathy is an idiopathic choroidal vascular disease that is characterized by a dilated network of choroidal blood vessels that have multiple terminal aneurysmal protuberances (in a polypoidal appearing fashion). This condition is not considered a “white dot syndrome.”
Which 3 of the following ophthalmologic manifestations are associated with malignant hypertension? (Select 3)
Cotton wool spots Papilledema Acute angle closure Hollenhorst plaques Chorioretinal retinal atrophy Flame-shaped hemorrhages
Cotton wool spots
Papilledema
Flame-shaped hemorrhages
Though unlikely to present in the office, a sudden significant rise in blood pressure can damage the delicate retinal vessel walls. This leads to flame-shaped hemorrhages or infarction of the nerve layer, producing cotton wool spots, and, in the most severe and long-lasting cases, papilledema. On the other hand, Hollenhorst plaques reflect an embolic phenomenon from thrombotic disease, usually from the carotid artery. Acute angle closure and chorioretinal atrophy are not associated with malignant hypertension.
At which location of the retina is the peak density of rod photoreceptors located?
- 5mm from the foveal pit
- 0mm from the foveal pit
- 0mm from the foveal pit
- 5mm from the foveal pit
- 5mm from the foveal pit
4.5mm from the foveal pit Correct Answer
In the human fovea there are no rod photoreceptors present; cones are the only photoreceptors in this area, and they are perfectly arranged in a hexagonal mosaic pattern. Outside of the foveal region, the rod photoreceptors are introduced, breaking up this tight hexagonal cone packing. However, this architecture is still very organized, as cones are rather evenly spaced around the rods. Cone density rapidly falls outside of the fovea and remains at a steady density in the peripheral retina. As the cone density rapidly declines, the rod photoreceptor density quickly increases to a peak density in a ring around the fovea (also known as the “rod ring”). This is located about 4.5mm from the center of the fovea (or 18 degrees from the foveal pit).
Which of the following layers of the choroid contains blood vessels with the largest diameter?
Choriocapillaris
Haller’s layer
Bruch’s layer
Sattler’s layer
Haller’s layer
Which of the following systemic diseases are MOST commonly associated with the presence of angioid streaks observed in the retina?
Sickle cell disease Marfan syndrome Paget's disease Ehlers-Danlos syndrome Pseudoxanthoma elasticum Your Answer
Pseudoxanthoma elasticum Your Answer
PEPSI = angoid streaks
P Pseudoxanthoma elasticum Ehlers-Danlos syndrome Paget's disease Sickle cell disease Idiopathic
Approximately 50% of patients who present with angioid streaks have an associated systemic disease; the other 50% of cases are considered idiopathic. Pseudoxanthoma elasticum (PXE) is by far the most commonly associated systemic disease in these patients. In general, PXE is a rather uncommon, inherited, generalized connective tissue disorder whereby tissues in the body containing elastin are significantly affected. Up to 85% of patients with PXE will develop ocular complications, usually after the second decade of life. The combination of PXE and ocular involvement with angioid streaks is referred to as “Gronblad-Strandberg syndrome.” Patients with PXE typically have characteristic signs of very loose skin folds and yellow skin papules that are commonly observed in the neck region, axillae, and on flexor aspects of joints. These patients also frequently suffer from cardiovascular disease caused by accelerated atherosclerosis and have an increased risk of developing gastrointestinal bleeds, which can be life-threatening.
Ehlers-Danlos syndrome is another systemic condition that is occasionally associated with the presence of angioid streaks. It is a rare, usually dominantly inherited disorder of collagen in the body that is caused by a deficiency of hydroxylysine. Systemic features include thin, hyperelastic skin, hyperextensible joints, cardiovascular disease, and other systemic lesions. Besides angioid streaks, patients with Ehlers-Danlos syndrome can also develop other ocular conditions such as lens subluxation, blue sclera, high myopia, keratoconus and retinal detachments.
Angioid streaks also occur in about 2-10% of patients diagnosed with Paget disease. Paget disease is a chronic, progressive (inherited in some cases) disease that is characterized by an enlarged skull, bone pain, frequent bone fractures, hearing loss, and cardiovascular complications. The disease may be localized to a few bones or may be generalized. In some cases, patients are even asymptomatic; however, in late stages, significant vision loss can ensue due to optic nerve compression from enlarging bone. Lab testing in these patients will show an increased serum alkaline phosphatase and urine calcium level.
Less common systemic disorders that may cause the formation of angioid streaks include sickle-cell disease, acromegaly, senile elastosis, lead poisoning, and Marfan syndrome.
What is the name of the funnel-shaped region anterior to the optic disc that represents the posterior termination of Cloquet’s canal?
Patellar fossa Hyaloid space Erggelet's space Berger's space Area of Martegiani
Area of MartegianiThe area of Martegiani signifies the funnel-shaped dilation surrounding the optic disc representing the posterior termination of Cloquet’s canal (also known as the hyaloid canal).
Berger’s space is an area between that anterior face of the vitreous body and the posterior lens capsule. It represents the anterior termination of Cloquet’s canal. It is also known as Erggelet’s space.
The patellar fossa characterizes the anterior depression of the vitreous body in which the crystalline lens resides.
A 35 year-old male presents to your office with sudden loss of vision in his left eye that began a few days ago following a chest-compressing injury that occurred at his work. Dilated fundus evaluation reveals multiple, superficial, white retinal patches, along with several superficial peripapillary hemorrhages. What is the MOST likely diagnosis for this patient?
Purtscher's retinopathy Your Answer Terson syndrome Retinal detachment Valsalva retinopathy Commotio retinae
Purtscher’s retinopathy is a retinal condition that typically occurs following severe trauma (especially to the head) or in patients with a history of a recent chest compressive injury. Patients will commonly present with severely decreased visual acuity in one or both eyes that develops either immediately or within 48 hours following the event. Retinal observations commonly include superficial, white, retinal patches resembling cotton-wool spots, pre-retinal and/or retinal hemorrhages, macular edema, dilated retinal veins, and possible optic disc edema or optic disc pallor.
The underlying pathophysiology of the development of Purtscher’s retinopathy is not fully understood; however, the classic mechanism proposes that the injury creates an intravascular hydrostatic shock wave that travels to the retinal vasculature and results in endothelial cell damage of the retinal veins, macular capillaries, and radial peripapillary capillaries. The problem with this theory is that it does not account for the development of this type of retinopathy in patients without a traumatic event (emboli, pancreatitis, connective tissue diseases, bone marrow transplantation, etc.). There is no known treatment for Purtscher’s retinopathy except for proper management of the underlying cause. Prognosis for visual recovery is variable because, although retinal findings tend to resolve within a few weeks, about 50% of patients will experience persistent prolonged blurring of central vision due to irreversible macular or optic nerve damage.
Terson syndrome occurs when a vitreous hemorrhage is accompanied by a subarachnoid hemorrhage. Commotio retinae appears as a grey-white discoloration of the retina that occurs following blunt ocular trauma. It is a result of the disruption of the photoreceptor outer-segments. This condition can present peripherally and may cause severe or permanent visual loss if damage occurs in the region of the macula.
In patients diagnosed with retinitis pigmentosa, which of the following inheritance patterns leads to the MOST severe presentation of the disease with the WORST prognosis?
X-linked Isolated, without family history Autosomal-dominant Autosomal-recessive Mitochondrial
X-linked
Retinitis pigmentosa (RP) is a retinal dystrophy in which the rod photoreceptor cells are initially preferentially affected, with eventual subsequent degeneration of the cone photoreceptors as well. Retinitis pigmentosa may develop as a result of an isolated sporadic disorder without any other family history or secondary to a genetic mutation (usually of the rhodopsin gene). RP has also been shown to be associated with certain systemic conditions.
The autosomal-dominant form of retinitis pigmentosa, along with the isolated sporadic form are the most common types and usually have the best prognosis. Autosomal-recessive types are less common and typically have an intermediate or guarded prognosis. The least common and most severe form of RP is due to an x-linked genetic mutation and commonly results in complete blindness by the time patients are in their 20’s or 30’s.
Which of the following blood vessels offers the greatest resistance and the lowest flow rate?
Choroidal vessels
Ophthalmic artery
Retinal vessels
Carotid artery
Retinal vessels
The greatest concentration of hyaluronic acid is found in which portion of the vitreous?
The cortex
The secondary vitreous
Cloquet’s canal
The primary vitreous
The cortex
The vitreal cortex is formed of condensed collagen fibrils, mucopolysaccharides and proteins which serves to envelop the vitreous body. The concentration of hyaluronic acid is approximately five to ten times greater than the inner vitreous.
The primary vitreous develops at around the third week of gestation. It is formed by mesoderm. The secondary vitreous begins to develop during the ninth embryonic week. This later becomes the mature vitreous. The secondary vitreous stems from primary vitreal cells and retinal glial cells and therefore originates from neuroectoderm. The secondary vitreous expands to fill the globs while compacting the primary vitreous in the center of the globe.
The hyaloid artery is a branch of the ophthalmic artery and is important for delivering nutrients to the lens and structures behind the lens during development. The artery disintegrates before birth leaving a canal in the primary vitreous called Cloquet’s canal. Remnants of this artery are often perceived as “floaters”.
On binocular indirect ophthalmoscopy of your 43 year-old patient, you see what appears to be a small U-shaped retinal tear in the far periphery at the 12 o’clock position of the left eye. You decide to use your 3-mirror Goldmann lens to obtain another view of the retina. Which 2 of the following modifications can be made in order to allow for the furthest possible peripheral view? (Select 2)
Tilt the Goldmann lens up
Tilt the Goldmann lens down
Have the patient look up
Have the patient look down
Tilt the Goldmann lens down Correct Answer
Have the patient look up Correct Answer
let the pt look where the lesion at , and the mirror at the opposite of it
lesion at 12 so the mirror should be up
Which of the following structures is NOT found in cones?
A synaptic terminal Ciliary process a.k.a. cilium Free-floating discs in the outer segment An inner segment Mitochondria
Free-floating discs in the outer segment
Cones and rods possess outer segments which consist of stacks of disc-like structures containing photopigment however, the discs of cones are not free-floating. The discs of cones remain attached as they migrate outwards. It was previously thought that only rods possessed a cilium but this has been proven to be inaccurate. Both rods and cones possess ciliary processes, inner segments, mitochondria and synaptic terminals. The synaptic terminals of rods differ in their morphology from cones in that they are slightly smaller and rounder and are called spherules while cones display a larger and flatter terminal called a pedicle.
Although controversial, it has been purported that supplementation of vitamin A is important in the management of retinitis pigmentosa. Which of the following agents, when taken in excess amounts, may interfere with the uptake of Vitamin A?
Calcium
Vitamin E
Vitamin B12
Vitamin K
Vitamin E Correct Answer
Vitamin A plays an important role in vision, and it is currently believed that daily supplementation of 15,000IU of Vitamin A may aid in decreasing the progression of retinitis pigmentosa. Research has demonstrated that taking increased levels of vitamin E simultaneously with higher doses of vitamin A may interfere with the uptake and distribution of vitamin A. Therefore, it is recommended that patients taking vitamin A for the management of retinitis pigmentosa avoid ingestion of higher amounts of vitamin E.
The proliferation of retinal pigmented epithelial cells that can be found at the junction of flat and detached retina typically indicates stability for which of the following minimum periods of time?
12 months 6 months 9 months 1 month 3 months
3 months
=demarcation line !!!
The presence of a pigmented demarcation line at the junction of flat and detached retina in cases of a rhegmatogenous retinal detachment (along with other features) can aid in determining the length of time the retinal detachment has been present. These demarcation lines (also known as “high water marks”) occur due to the proliferation of retinal pigment epithelial cells and commonly take about 3 months to develop. Their configuration is usually convex with respect to the ora serrata and represents sites of increased adhesion. With time, the demarcation line tends to lose its pigment and can be less obvious upon fundus examination.
Drusen typically deposit between which layers of the retina?
The ganglion cell layer and the nerve fiber layer
The inner and outer nuclear layers
The retinal pigment epithelium and Bruch’s membrane
The inner and outer plexiform layers
The retinal pigment epithelium and Bruch’s membrane
Your 65-year-old female patient has been diagnosed with a macular hole in her left eye and shows vitreomacular traction in her right eye. Which of the following BEST describes the diagnosis of her right eye’s findings?
Epiretinal membrane
Stage 1 macular hole
Stage 0 macular hole
Macular pseudo hole
Stage 0 macular hole
- Abnormal vitreofoveal traction (usually observed only by OCT) in the fellow eye of a patient with a macular hole
- This eye has an elevated risk of macular hole formation with this presentation (43%), as compared to those without this abnormal vitreomacular appearance, in which the risk is very low for a subsequent hole formation
