1. The neurosensoryretina isembryologicallyderived from ____;and injury causes____

-the DIENCEPHALON-GLIOSIS

2. The adult vitreous -is AVASCULAR, but it can beopacified by hemorrhage from traumaor retinal neovascularization-age related liquefaction and collapseof the vitreous gives rise to "floaters"in the visual field

3. Retinal detachment -separation of the neurosensory retinafrom the retinal pigmented epithelium(RPE) is classified based on thepresence or absence of a break in theretina

1) Rhegmatogenous retinaldetachment - associated with a full-thickness retinal defect developingwhen structural collapse of thevitreous exerts traction on the retinalinternal limiting membrane; liquefiedvitreous humor then seeps throughthe tear and separates theneurosensory retina and RPE

2) Non-rhegmatogenous retinaldetachment (without a retinal break) -occurs when exudates accumulate orfluid leaks from the choroidalcirculation beneath the retina (e.g.,with choroidal tumors or malignantHT)

4. Retinal Vasculardisease(neovascularization)

-a common end-point of numerousinsults-it can occur secondary to vesselocclusion, hypoxia, or primaryangiogenic factor production*RETINAL HYPOXIA - causesgrowth factor production (e.g.,vascular endothelial growth factor[VEGF]), --->angiogenesis; **bleeding, increased vascularpermeability, or subsequentcontraction of the neovascularmembrane can cause retinaldetachment

5. Hypertension -results in retinal arteriosclerosis with wallthickening-In malignant HT, damaged choroidal vesselscan cause choroidal infarcts (ELSCHINGPEARLS) or exudate accumulation b/w theneurosensory retina and RPE (causingdetachment)-Occlusion of retinal arteries causes infarcts ofthe retinal nerve fiber layer, and exudates fromdamaged retinal vessels accumulate in theouter plexiform layer

6. DiabetesMellitus

-Causes MICROVASCULAR INJURY withthickened basement membrane (andphysiologic breakdown of the blood-retinabarrier with edema and hemorrhage), as wellas pericyte loss leading to characteristicmicroaneurysms

1) Background (pre-proliferative) diabeticretinopathy-constitutes a spectrum of structural andfunctional abnormalities of angiogenesisrestricted to the retina (i.e. beneath theinternal limiting membrane)

2) Proliferative diabetic retinopathy-reflects new vessels (retinalneovascularization) that breach the retinalinternal limiting membrane-retinal neovascularization can beaccompanied by a neovascular membrane onthe iris secondary to elevated aqueous humorVEGF levels; contraction of this membrane -->adhesions that occlude aqueous outflow andprecipitate glaucoma

7. Retinopathyofprematurity

*immature retinal vessels respond to increasedoxygen tension (administered to prematureinfants) by constricting, resulting in localischemia

8. SickleRetinopathy,RetinalVasculitis,RadiationRetinopathy

*reduced oxygen tension leads to erythrocytesickling and microvascular occlusions*Vasculitis and ocular radiation both damagevessels, producing zones of retinal ischemia

1357-1365Study online at quizlet.com/_8is3s

9. Retinalartery andveinocclusions

*arterial occlusions due to atherosclerosis orto atheroembolism cause retinal infarction-since this onset is TYPICALLY SUDDEN,there is no prolonged ischemia, and hence nosignificant neovascularization

*retinal VEIN occlusion (e.g. due to arteriolarthickening in hypertension that compromisesthe venous lumen where the vessels cross)typically leads to ischemia and subsequentneovascularization

10. Age relatedmaculardegeneration(ARMD)

**The most common cause of IRREVERSIBLEvisual loss in the U.S.-more than 70% of cases are hereditary-onset is influenced by env. exposures (e.g.smoking)-any disruption of RPE, its basementmembrane (Bruch membrane), or theassociated choroidal vasculature affects theoverlying photoreceptors and causes visualloss

1) ATROPHIC (dry) ARMD - most common(80-90%)-associated with geographic atrophy of theretinal pigment epithelium and deposits(drusen) in the Bruch membrane

2) EXUDATIVE (wet) ARMD - (10-20%) isassociated with OVERALL GREATER VISIONLOSS-it is caused by leaky choroidal neovascularmembranes-therapy involves VEGF antagonists to blockthe vessel formation

11. RetinitisPigmentosa

-collection of fairly common inheriteddisorders that affect various aspects of vision,including visual cascade and cycle, structuralgenes, transcription factors, catabolicpathways, and mitochondrial metabolism*NOT primarily inflammatory-both rods and cones are lost to apoptosis andthere is retinal atrophy, with perivascularretinal pigment accumulation

12. Retinoblastoma *most common primary intraocularmalignancy of CHILDREN-prognosis is worsened with extraocularextension or optic nerve or choroidalinvasion-in 40% of cases, retinoblastoma isassociated with a germ-line RB mutation;such cases are often bilateral and areassociated with pinealblastoma with adismal outcome-retinoblastoma tends to spread to brainand marrow, with rare dissemination tothe lung

*Morphology-tumors contain UNDIFFERENTIATED(i.e. small, round cells) and differentiatedelements encircling blood vessels withzones of necrosis and dystrophiccalcification-well-differentiated tumors exhibitFLEXNER-WINTERSTEINER ROSETTES,reflecting abortive photoreceptordevelopment-degree of diff. does not influenceprognosis

13. AnteriorIschemic OpticNeuropathy

-the optic nerve supply can be interruptedby vascular inflammation (e.g. temporalarteritis) or by embolism or thrombosis

14. Papilledema -optic nerve edema can be caused byCOMPRESSION (e.g. by neoplasm) or byelevated CSF pressure; the latter is typicallybilateral (papilledema)-Papilledema associated with increasedintra-cranial pressure is not typicallyassociated with visual loss

15. GlaucomatousOptic NerveDamage

-characterized by atrophy (due to increasedintraocular pressures)-accompanied by optic nerve head cupping

*In NORMAL-TENSION GLAUCOMA, thesame changes are seen WITHOUTINCREASED INTRA-OCULARPRESSURES

*mutations in the OPTINEURIN GENE areimplicated

16. Other OpticNeuropathies

1) inherited - e.g. Leber hereditary opticneuropathy = due to MITOCHONDRIALGENE MUTATIONS

2) Toxins - e.g. methanol

3) nutritional deficiency

17. OpticNeuritis

-common feature = visual loss secondary to OPTIC NERVE DEMYELINIZATION-not all are inflammatory

** MULTIPLE SCLEROSIS = most important cause of optic neuritis

18. PhthisisBulbi

*The End-Stage Eye-Trauma, intraocular inflammation, chronic retinal detachment, and many other conditions give rise to a small (atrophic)and internally disorganized eye: PHTHISIS BULBI