SUR 104 - ophthalmology

  1. goal of ophthalmologic surgery
    restore vision lost as a result of disease, injury or congenital defect
  2. 7 bones that come together to form the orbit
    • frontal
    • lacrimal
    • sphenoid
    • ethmoid
    • maxillary
    • zygomatic
    • palatine
  3. where does optic nerve enter?
    posterior orbital cavity through optic foramen
  4. what are eyelids composed of?
    fibrous connective tissue (tarsal plate)
  5. palpebral
  6. space or interval between upper and lower lids
    palpebral fissure
  7. juncture of eyelids
  8. secrete waxy oil that seals eyelids when closed
    sebaceous glands located along lid margin and in lacrimal caruncle
  9. what do eyelashes do?
    protect eye from airborne particles
  10. 2 spaces of anterior cavity of globe
    anterior and posterior chambers
  11. how many muscles attach sclera to bony orbit?
  12. 4 rectus muscles
    • superior
    • inferior
    • lateral
    • medial
  13. 2 oblique muscles
    • superior
    • inferior
  14. vision is normally...
  15. what does visible area consist of?
    central and peripheral vision
  16. thin, transparent mucous membrane that lines each eyelid and covers sclera
  17. regions of conjunctiva
    palpebral and bulbar regions
  18. part of conjunctiva that is highly vascular and pink, lines eyelids and extends over cornea
    palpebral conjunctiva
  19. part of conjunctiva that covers anterior portion of eyeball up to junction of sclera and appears white
    bulbar conjunctiva
  20. clear tissue layer overlying the front of eyeball
  21. 3 tissue layers of cornea
    • epithelium
    • stroma
    • endothelium
  22. where does refraction take place?
    in the cornea
  23. where do the tissues of the cornea come together?
  24. initial incision of cataract surgery
    at the limbus
  25. thick, white, fibrous tissue that encloses about 3/4 eyeball
  26. what part of the eye communicates with optic nerve sheath?
  27. highly vascular, pigmented layer that lies directly beneath the sclera
    choroid layer
  28. primary function of choroid
    to prevent reflection of light within eyeball
  29. extension of the choroid layer, located at periphery of anterior choroid
    ciliary body
  30. what is the ciliary body composed of?
    smooth muscle tissue, to which suspensory ligaments are attached
  31. pigmented membrane composed mainly of muscle tissue that surrounds the pupil
  32. innermost layer of globe
  33. what does the retina do?
    • it is the photoreceptive layer of the eye
    • receives and transmits images to the brain via optic nerve
  34. distinct area of acute vision
  35. center of macula
    fovea centralis
  36. area of dense neurons in which the optic nerve exits the globe
    optic disc
  37. how many photoreceptors does optic disc contain?
  38. clear, biconvex disk contained in a transparent capsule, lying directly behind the iris
  39. how is the lens held in place?
    suspensory ligaments called zonules
  40. what fills the anterior chamber of the anterior eye?
    aqueous humor (produced by ciliary epithelium)
  41. through what does aqueous humor pass?
    through the pupil and into the canal of Schlemm
  42. what is the posterior chamber filled with?
    vitreous humor
  43. what is vitreous humor?
    gel-like substance that nourishes the inner tissue layers, gives shape to the posterior globe and acts as a refractive medium for light
  44. what does the lacrimal apparatus do?
    produces tears
  45. lacrimal apparatus consists of:
    • lacrimal gland
    • caruncle
    • tear ducts
    • lacrimal sac
    • nasolacrimal duct
  46. opening of each duct of lacrimal apparatus
    lacrimal punctum
  47. what are tears composed of?
    proteins, mucus, sodium chloride, glucose and enzymes
  48. bending of light rays through a transparent medium
  49. process in which lens continually changes shape to maintain focus of an image on the retina
  50. what is test for visual acuity performed with?
  51. what is a slit lamp used for?
    to examine anterior chamber of the eye
  52. what is used to stain the cornea and highlight irregularities of the epithelial surface?
  53. what is used to measure the intraocular pressure?
  54. what is direct examination of the eyes performed with?
  55. what does an ophthalmoscope do?
    magnifies the focal point
  56. what is used extensively in the diagnosis and evaluation of retinal and choroid diseases?
    fluorescein angiography
  57. what is used to measure the density of eye tissues and detect abnormalities?
    ophthalmic ultrasonography
  58. what does a B-scan ultrasound do?
    produces image of the target tissue that shows a series of spots, brightness of which corresponds to tissue density
  59. what does an A-scan ultrasound do?
    depicts tissue density as amplitude on two axes
  60. what tests are used in the evaluation of the orbital and intracranial structures?
    MRI and CT
  61. opaque lens
  62. most common cause of cataracts?
  63. inflammation or infection of lacrimal sac
  64. dacryocystitis usually arises from?
    obstruction of lacrimal canal
  65. inversion of eyelid (lower lid)
  66. drooping or eversion of eyelid
  67. optic nerve and visual field damage
  68. what is glaucoma usually caused by?
    inadequate drainage of aqueous humor - unrelieved pressure damages optic nerve and may result in progressive blindness
  69. degeneration of the rod and cone photoreceptor cells of the retina
    macular degeneration
  70. most common cause of blindness in people over age 65
    age-related macular degeneration (ARMD)
  71. separation or tear in retina, allowing vitreous to seep between layers and delaminate them
    retinal detachment
  72. inability to coordinate the extraocular muscles
  73. cause of strabismus
    • weakness of paralysis of muscles
    • can be congenital or acquired
  74. what condition is a medical emergency that requires surgery?
    retinal detachment
  75. lens implants are treated in much the same way as?
  76. what type of table is used in most facilities for a patient acquiring ophthalmic surgery?
    combination stretcher-operating table because shifting the patient immediately after surgery may result in increased IOP and eye injury
  77. what types of anesthetic is used for most ophthalmic surgeries?
    regional block and monitored sedation
  78. antiseptics used for eye prepping
    dilute povidone-iodine (5% or as directed by MD) and hexachlorophene
  79. supplies needed for sterile prep setup
    • small basins
    • surgical towels
    • plastic towel drapes
    • lint-free gauze sponges
    • cotton balls
    • cellulose eye sponges
    • balanced salt solution (BSS)
  80. prep area
    eyelid and margins, inner and outer canthus, brows and face, ending at chin
  81. how is prep solution runoff prevented?
    by squeezing excess solution from each sponge and a small piece of cotton placed in operative side ear
  82. type of anesthetic used for pediatric patients
    general anesthetic
  83. what is lidocaine with epinephrine used for?
    to maintain vasoconstriction at the operative site
  84. mydriatic drugs
    phenylephrine (Neo-Synephrine, Mydfrin)
  85. what do mydriatic drugs do?
    dilate the pupil
  86. what are mydriatic drugs used for?
    • examination of the retina
    • testing of refraction
    • easier removal of lenses
  87. cycloplegic drugs
    • Atropine
    • epinephrine
  88. what does atropine do?
    • dilates pupil, inhibits focusing, anticholinergic, potent
    • long duration of action (7-14 days)
  89. what does epinephrine do?
    dilates pupil, added to BSS for irrigation to maintain pupil dilation during cataract surgery or vitrectomy
  90. miotic drugs
    • carbachol (Miostat)
    • acetylcholine chloride (Miochol-E)
  91. what do miotic drugs do?
    • constrict pupil
    • used intraocularly during anterior segment surgery
  92. topical anesthetics
    • tetracaine hydrochloride
    • proparacaine hydrochloride
  93. onset of topical anesthetics
    5-20 sec
  94. duration of action of topical anesthetics
    10-20 min
  95. injectable anesthetics
    • lidocaine (Xylocaine)
    • bupivacaine (Marcaine, Sensorcaine)
    • mepivacaine (Carbocaine)
  96. onset and duration of lidocaine
    • onset - 4-6 min
    • duration - 40-60 min, 120 min with epinephrine
  97. onset and duration of bupivacaine
    • onset - 5-11 min
    • duration - 8-12 hours with epinephrine
  98. onset and duration of mepivacaine
    • onset - 3-5 min
    • duration - 2 hour (longer with epinephrine)
  99. additives to local anesthetics
    epinephrine (prolongs anesthesia and reduces bleeding)
  100. viscoelastics
    Healon in sterile syringe assembly
  101. what is Healon used for?
    • lubricant and support
    • maintains separation between tissues to protect endothelium, maintain anterior chamber intraocularly and prevent postoperative increase in pressure
  102. requirements for Healon use
    • should be refrigerated
    • allow 30 min to warm to room temp
  103. irrigant used
    BSS - used to keep the cornea moist during surgery
  104. hyperosmotic agent
    mannitol (Osmitrol) - reduces IOP
  105. anti-inflammatory agent
    betamethasone sodium phosphate and betamethasone acetate suspension (Celestone) - prophylaxis
  106. what is cocaine used for?
    used on cornea to loosen epithelium before debridement and on nasal packing to reduce congestion of mucosa
  107. what is fluorescein used for?
    • IV - diagnose retinal disorders
    • topical - stains cornea
  108. 2 types of ESU systems commonly used in eye surgery
    • single-use, battery-powered cautery
    • bipolar unit
  109. handheld battery ESU has?
    very small filament tip that becomes hot when the unit is activated
  110. what does the filament of handheld ESU do?
    coagulates very small vessels of the eye, but does not cut
  111. when is bipolar ESU used?
    procedures in which fine cutting and coagulation are required
  112. what are eye sponges made of?
    lint-free cellulose
  113. is sponge used on cornea?
  114. how does the sponge absorb fluid?
    by wicking - done by holding the tip of the sponge in contact with the fluid and allowing the sponge to absorb it
  115. eye suture sizes
    from 4-0 to 12-0
  116. how should eye sutures be handled?
    as little as possible
  117. types of sutures frequently used to close circumferential incisions
    double-arm sutures
  118. procedure in which nodal tissue arising from a sebaceous gland is excised from the tarsal plate
    chalazion excision
  119. inflammatory, benign growth that originates in sebaceous gland of eyelid
  120. how is chalazion excision performed?
    lid is everted and vertical incision is made through tarsal plate
  121. goal of entropion repair
    restore eyelid to correct anatomical position by resection
  122. what is entropion caused by?
    weakness and imbalance of eyelid muscles
  123. goal of ectropion repair
    restore eyelid to normal position
  124. how is ectropion repair performed?
    wedge of tissue is removed from lower tarsal plate and canthal tendon is secured to periosteum of orbital rim
  125. cause of ectropion
    • age
    • congenital
    • Bell palsy
  126. goal of pterygium repair
    membrane is surgically removed to prevent loss of vision
  127. patch of degenerative elastic tissue that proliferates from the conjunctiva in response to chronic irritation
    pterygium - appears as a white or yellowish vascular mass
  128. when is pterygium surgery indicated?
    when documented growth has occurred, lesion is close to the visual axis or vision is impaired
  129. creation of permanent opening in tear duct for drainage of tears
  130. inflammation of lacrimal sac, causing pain, redness and swelling of medial canthus
  131. 2 groups of patients in which lacrimal sac inflammation and infection usually are seen
    • adults over age 40
    • infants
  132. goal of dacryocystorhinostomy
    reestablish drainage into lacrimal duct system
  133. alternative method of dacryocystorhinostomy
    stent with silicone tubing
  134. goal of lacrimal duct probing
    lacrimal duct is opened and obstruction is removed
  135. most common sign of abnormality of lacrimal system
    constant tearing
  136. how is punctum checked for patency during lacrimal duct probing?
    with a 2-mL syringe and cannula
  137. what is done if lacrimal duct probing does not relieve obstruction?
    silicone tube may be implanted
  138. goal of muscle resection and muscle recession
    correct deviation of the eye caused by strabismus
  139. 2 procedures commonly used to treat strabismus
    • lateral rectus resection
    • medial rectus recession
  140. what is done in lateral rectus resection?
    portion of the muscle is excised and the severed end is reattached at the original site of insertion, limiting the drift of the eye
  141. what is done in medial rectus recession?
    muscle is detached from its insertion, moved posteriorly, and reattached, releasing the eye and allowing it to move farther in lateral position
  142. during muscle resection/recession, what can traction on the muscles cause?
    • vagal response, resulting in bradycardia
    • surgeon will then temporarily release traction on muscles
  143. full-thickness transplantation of donor cornea to restore vision
  144. most common causes of corneal opacification
    • chemical and thermal burns
    • infection
    • degenerative disease
  145. 2 types of corneal transplantation
    • lamellar (partial penetrating)
    • penetrating (full-thickness)
  146. goal of LASIK surgery
    shape curvature of the cornea and correct refractory problem
  147. what is LASIK surgery performed with?
    excimer laser
  148. hyperopia
    • farsightedness
    • anterior-posterior distance of the globe is too short
    • images that are close are blurred because focal point is behind retina
  149. myopia
    • nearsightedness
    • anterior-posterior distance of the globe is too long
    • focal point lies in front of retina
  150. astigmatism
    uneven curvature of refractive medium
  151. activities after LASIK surgery
    avoid activities requiring bending or kneeling for the first week after surgery
  152. fragmentation of tissue by ultrasonic vibration
  153. most common form of cataract removal
  154. goal of cataract extraction
    remove opaque lens and replace with an intraocular lens implant to restore vision
  155. what is instilled into the eye during cataract prep for antibacterial effect?
    Betadine 10%
  156. what complication is most common in the first 2-3 days after cataract surgery?
    blood in the anterior chamber of the eye
  157. goal of anterior vitrectomy
    to remove vitreous from anterior chamber, for example if vitreous is overhydrated during cataract surgery
  158. major complication of vitrectomy
    retinal detachment
  159. when is scleral buckling performed?
    when sensory layer of retina becomes separated from pigment epithelial layer
  160. what does a tear in the retina cause?
    sudden, painless loss of vision or "shadowing" (like a curtain) with often light flashes and floaters
  161. what is a tear in the retina called?
    rhegmatogenous detachment
  162. how is retinal detachment repaired?
    adhesions are produced between the layers using cryotherapy or diathermy, followed by scleral buckling
  163. what is involved in scleral buckling?
    • Silastic or foam band is attached to the sclera
    • synthetic buckles are placed over the band, causing it to indent and puts the tissue in close contact with retina during healing
  164. what is done when vitrectomy is performed in conjunction with scleral buckling?
    vitreous gel is replaced with Healon or gas through small puncture wound - used to eliminate traction and tearing on the retina
  165. what does intravitreous gas injection do?
    exerts pressure on the retina while subretinal fluid is reabsorbed
  166. gases that are injected intravitreously
    • sulfur hexafluoride
    • perfluoropropane
  167. why is trabeculectomy performed?
    to create a channel from which the aqueous humor may drain from the anterior chamber for the treatment of glaucoma
  168. group of diseases characterized by optic nerve damage and visual field loss
  169. IOP is normally maintained by what?
    aqueous humor
  170. type of glaucoma with sudden rise in IOP caused by total blockage or obstruction of aqueous humor at root of iris
    primary angle closure glaucoma
  171. type of glaucoma that occurs in both eyes in which outflow of aqueous humor is obstructed in trabecular meshwork
    primary open angle glaucoma
  172. subtype of open angle glaucoma in which intraocular pressure is normal, there is retinal damage and visual field loss with migrain and optic disc hemorrhage
    normal tension glaucoma
  173. type of glaucoma in which the fluid drainage system is abnormal at birth - infant's eye distends and corneal haziness occurs
    congenital glaucoma
  174. goal of argon laser trabeculoplasty
    shrink collagen and stretch canal of Schlemm, expanding canal, increasing drainage and reducing IOP
  175. most common complication of laser surgery for glaucoma
    increase in pressure in the eyes
  176. goal of orbital decompression
    one or more bony sections of orbital cavity are removed to reduce pressure on optic nerve
  177. indications for orbital decompression
    • to treat hyperthyroidism (Graves' disease)
    • to treat pressure on optic nerve caused by tumor or swelling
  178. most common approach to orbital decompression
    through the lower lid
  179. complete removal of eyeball
  180. procedure in which contents of the eye are removed, but outer shell of the sclera and muscle attachments are left intact
  181. indications for enucleation
    intraocular malignancy, penetrating ocular wound, painful blind eye, painless, disfigured blind eye
  182. implant that is inserted to shape orbital cavity
  183. placed over sphere and covers its surface
  184. most common orbital implant materials
    • porous polyethylene
    • hydroxyapatite
  185. removal of entire eye and orbital contents, including eyelids, ocular muscles and orbital fat
    orbital exenteration
  186. indications for orbital exenteration
    cancer, only after all other therapies have failed
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SUR 104 - ophthalmology