Opthmalmology Flashcards
Eye muscle movements
Lateral Rectus: Abduct CN6 Medial Rectus:Adduct Superior Rectus: Elevate, adduct Inferior Rectus: Depress, adduct Superior Oblique: Elevate, abduct, internally rotate CN Inferior Oblique: depress, abduct
Tear Film parts
Top-Bottom
Oil: Tarsal glands, lid margin. Stops evaporation
Aqueous: Lacrimal Gland (accesory)
Mucin: Made by conjunctiva
Neurogenic Ptosis
CN3 palsy: Optic muscle dysfunction, Levator palpebrae superioris drooped, pupil parasympathetic as with third nerve (big pupil, due to sympathetic drive)
Sympathetic (Horner’s Syndrome): Subtle ptosis, subtle miosis (anhydrosis)
Orbital blow out fracture signs and consequence
Maxillary floor breaks, contents fall into the sinus
Black eye, pain on upgaze and down gaze, nerve anaesthesia (infraorbital nerve)
Hyperopia
Myopia
Long sighted, image forms behind retina. Shorter eye
Short sighted, image forms before retina. Longer eye
Cornea Composition and function
Seen by slit lamp
Cornea is highly___
Role of endothelial cells:
Epithelium Bowmans membrane Stroma with lamellae Descemets Single layer of endothelium
Allows passage of light through, refraction of light! Due to curvature and refractive index
Innervated
Endothelium pumps water out of the stroma into the aqueous
Cornea requires what for good function
Clarity: Reduced by scars, infection
Curvature: altered by keratoconus
Controlled thickness: Increased in endothelial problems, post surgery. Decreased by keratoconus
Lens structure, function
Cataracts
Cellular structure in the posterior part of the anterior chamber. ECM layer on outside, epithelium and fibre cells?
Lens damage, cortical and nuclear (worse) e.g protein aggregations
Ciliary Body and accomodation
Ciliary epithelium
Ciliary muscle, all around the eye Joins ___ with suspensory ligaments. Important for_____
When ciliary muscle contracts, makes lens ___ (as circular, ring squeeze) to bend more light, for close up
When relax, ligaments pull tight, making lens ____
Epithelium: Produce aqueous humour, Flows from pupil into ______ in anetrior chamber where it drain. If this is blocked, can cause an increase in intraocular pressure
Ciliary muscle, all around the eye Joins lens with suspensory ligaments. Important for accomodation.
When ciliary muscle contracts, makes lens fatter (as circular, ring squeeze) to bend more light, for close up
When relax, ligaments pull tight, making lens thinner
Epithelium: Produce aqueous humour, Flows from pupil into trabecular meshwork in anetrior chamber where it drain. If this is blocked, can cause an increase in intraocular pressure
Cataract aetiolgy
Age related is majority, diabetes get it earlier
Corticosteroids (e.g rheumatoid arthritis, etc)
Uveitis
Function of retina
Absorb photons of light, translate light into a biochemical message, these biochemical-electrical impulses, transmit these to brain
Anatomy of retina
Central versus peripheral retina
Outer layer of ganglion cells; Bipolar cells; Rods and cones (photoreceptors)
Innermost layer is rods and cone, as they sit on a membrane (retinal pigment epithelium) that supplies nutrients and removes waste.
Central: more rods and cones, peripheral less
Function of fovea and macula lutea
Fovea: Pit where bipolar cells, gangliom cells are moved out of the way. Light goes directly onto this. Cone peak at fovea, peripherally more rods (peak is a bit further out from fovea). Visual Acuity
Macula lutea: Contains xanthophyll carotenoids to protect fovea
Glaucoma. Open and closed
Rsik factors
mid dilated pupil, swollen, sore. closed angle
Vision loss is ___, also papilloedema
Optic neuropathy, associated with high intraocular pressure (normal 11-20). Very common in old age
Open angle: Trabecular meshwork partially occluded, less flow of aqueous humour. Old age
Closed angle: Iris bows forward in short eyes, and closes the trabecular meshwork/angle
Hypertensnion, myopia, FHx
Arcuate, or around periphery first, tunnel vision
Common Retinal disorders
Diabetic retinopathy
Old age macular degeneration
