Eye Flashcards
(35 cards)
Mention clinical & microscopic finding of retinitis pigmentosa
Night blindness & constricted visual fields due to loss of rods. As cones are lost, central visual acuity may be affected; and may progress to complete blindness
Histologically, both rods & cones are lost by apoptosis with 2ry proliferation of retinal pigmented epithelium.
Visual effects of albinism are…….
Photophobia, nystagmus, amblyopia
Define hordeolum
Acute suppurative inflammation may be external in the sebaceous glands of Zeis, the apocrine glands of Moll and eyelash follicles or less commonly internal in Meibomian glands
Describe etiology and microscopic pic of chalazion
Chronic inflammatory inflammation of the Meibomian glands due to obstruction to the drainage of secretions. This begins with destructions of meibomian glands and duct and subsequently involves tarsal plate.
Histologically, chronic inflammatory granuloma located in the tarsus and contains fat globules in the center of the granulomas i.e. appearance of a lipogranuloma
Microscopic pic of conjunctivitis
In acute stage, there is corneal edema and infiltration by inflammatory cells, affecting the transparency of cornea. In chronic stage, there is proliferation if small bv in normally avascular cornea & infiltration by lymphocytes and plasma cells with dissolution of corneal stroma by collagenase
Pathogenesis of trachoma
Caused by chlamydia or TRIC agents. Trachoma is caused by C.trachomatis while inculsion conjunctivitis is caused by C.oculogenitalis
Microscopic pic of trachoma
In early stage, intracytoplasmic inclusion bodies formed by the proliferating microoganisms within the cells
Later conjunctiva thickens due to dense inflammatory cell infiltrate. The end result is extensive corneal & conjunctival scarring, eye lid distortion, abrasion of cornea, in-turned eyelashed and blindness.
Microscopic pic of sympathetic ophthalmia
Granulomatous uveal inflammation consisting of epithelioid cells, lymphocytes & eosinophils. No necrosis or neutrophils or plasma cells.
Endophthalmia is inflammation of……while pan-ophthalmitis is inflammation of….
Interior of eye involving vitreous humor
Interior of eye extends to retina, choroid & sclera
Mention 2 types of diabetic nephropathy
Background (non-proliferative) & proliferative (retinitis proliferans)
Enumerate features of diabetic background retinopathy
- BM is thickened
- Degeneration of pericytes & some endothelial cell loss
- Macular edema due to leaky circulation
- Capillary microaneurysms
- Waxy exudates around microaneurysms esp in elderly due to hyperlipidemia
- Dot & blot hemorrhages in deeper layers of retina due to extravasation of erythrocytes
- Cotton-wool spots on retina which are microinfarcts of nerve fiber layer
- Exudate in retinal outer plexiform layer
Mention features of proliferative retinopathy
- Neovascularization of the retina around optic disc
- Friability of newly formed vessels leading to vitreous hemorrhage
- Proliferation of astrocytes & fibrous tissue around new bv
- Fibrovascular & gliotic tissue contracts to cause retinal detachment & blindness
Mention effects of severe diabetes on eye
- Diabetic iridopathy may lead to adhesion of cornea & iris (ant synechiae) or iris & lens (post synechiae)
- Iris neovascularization with subsequent 2ry angle-closure glaucoma
- Cataract of lens at an earlier age than general population
Mention features of hypertensive retinopathy
- Variable degree of arteriolar narrowing due to arteriosclerosis
- Flame-shaped hemorrhages in retinal nerve fiber layer
- Macular star a sponge-like arrangement of exudate in the macula in malignant HTN — results from exudate accumulating obliquely in the outer plexiform layer of macula
- Cotton-wool spots & microaneurysms
- Arteriovenous nicking (resulting in occlusion of retinal vein branches)
- Exudate in retinal outer plexiform layer
Compare ischemic & nonischemic retinal vein occlusion
Ischemic: angiogenic factors are upregulated in retina leading to neovascularization of retina, surface of optic nerve & iris with subsequent angle-closure glaucoma
NonI: may be complicated by hemorrhages, exudates & macular edema
Cause of pinguecula & pterigium
What is the difference between them?
Due to actinic damage thus occurs in sun-exposed areas occurs in old age, more in males, associated with prolonged exposure to UV and alcohol consumption
-pinguecula is limited to bulbar conjunctiva, pterigium originates in conjunctiva astride the limbus and migrates towards cornea
Histological characteristics of pterygium
There is fibrovascular CT that migrates from the conjunctiva to cornea, dissecting into plan of bowman layer this lewpads to fragmentation of it with variable acute and chronic inflammatory infiltrate.
Compare “dry” & “wet” AMD
D, diffuse or discrete deposits in Bruch membrane (drusen) and geograpgic atrophy of RPE
W, choroidal neovascularization. The vessels may leak and exuded blood may be organized by RPE into macular scars. Occasionally these vessels give rise to diffuse vitreous hemorrhages
Define retinal detachment
It is separation of neurosensory retina from RPE. It may occur spontaneously in persons older than 50 or may be 2ry to head/neck trauma.
Compare Rhegmatogenous and nonR retinal detachment
R, associated with a full thickness retinal defect. This is due to pathological processes in vitreous or anterior segment, causing traction on points of abnormally strong adhesion to retinal internal limiting membrane.
NR, no retinal break: may be due to retinal vascular disorders associated with significant exudation and any condition that damges the RPE and permits fluid to leak from choroidal circulation under retina e.g. HTN. OR Choroidal tumors.
Define phthisis bulbi and its histological characters
It is the end-stage of advanced degeneration and disorganizatiom of the entire eyeball inw which the IOP is inc and eyeball shrinks. The causes are trauma, glaucoma & intraocular inflammations.
Hist, marked atrophy & disorganization of all ocular structures, and the markedly thickened sclera. Even osseous metaplasia may occur.
Enumerate causes of cataract
- Senility due to degeneration of lens protein
- Congenital (Dowm, rubella, galactosaemua)
- Traumatic
- Metabolic due to formation of abnormal opaque protiens
- Drugs, smoking & heavy alcohol consumption
Histological features of cataract
Degeneration, fragmentation, liquefaction of lens fibers.
Compare open and closed angle glaucoma (define)
O, result from an increased resistance to aqueous outflow in the open angle
C, peripheral zone of iris adheres to the trabecular meshwork and physically impedes the outflow of aqueous humor
