7.3 Corneal ectasia

Card Set Information

Author:
ijesc
ID:
302771
Filename:
7.3 Corneal ectasia
Updated:
2015-05-24 10:52:58
Tags:
OPTM3131
Folders:
OPTM3131
Description:
Diseases
Show Answers:

Home > Flashcards > Print Preview

The flashcards below were created by user ijesc on FreezingBlue Flashcards. What would you like to do?


  1. What are corneal ectasias? (3)
    • primary progressive
    • degenerative
    • protrusion/bulging of the cornea
  2. Types of corneal ectasia (5)
    • keratoconus
    • pellucid marginal degeneration
    • keratoglobus
    • posterior keratoconus
    • post-LASIK ectasia (keratectasia)
  3. What is PMD?
    pellucid marginal degeneration
  4. Which type of corneal ectasia is most common?
    keratoconus
  5. Keratectasia is also known as
    Post-LASIK ectasia
  6. Post-LASIK ectasia is also known as
    keratectasia
  7. Which 3 types of corneal ectasias are rare?
    • post keratoconus
    • keratoglobus
    • PMD
  8. Is posterior keratoconus congenital or acquired?
    congenital
  9. Keratoglobus is __________ corneal thinning and steepening
    generalised
  10. PMD is ______________ thinning and steepening
    peripheral
  11. KC is also known as
    keratoconus
  12. What type/shape does KC have?
    nipple/oval cone type
  13. KC is ______ or ________ __________ thinning and steepening
    • central
    • mildly paracentral (nasal/inf)
    • localised
  14. Does KC have limited progression? Why?
    • Yes
    • forme fruste
  15. What does form fruste mean?
    incomplete/unusual form of a disease
  16. Keratoglobus is __________ thinning and often thinner at the _____
    • limbus to limbus
    • edges
  17. In keratoglobus, the cone is ___% to ____% of the cornea and is not as steep as _____
    • 75
    • 90
    • KC
  18. Keratoglobus is associated with _________ disorders such as ____ and ______
    • collagen synthesis
    • Marfan's
    • Ehlers-Danos VI
  19. What are the suggested 2 forms of keratoglobus?
    • congenital
    • adult onset
  20. What does a 'blue sclera' suggest?
    • collagen synthesis problems
    • thin sclera = can see choroidal vessels
  21. What is the age range for PMD?
    20-50yrs
  22. PMD is:
    common/rare
    unliateral/bilateral
    progressive/stable
    peripheral/central thinning if the cornea
    • rare
    • bilateral
    • progressive
    • peripheral
  23. Which part of the cornea is usually affected?
    inf/sup/nas/temp
    inferior
  24. What symptoms are observed in PMD? (3)
    • decr VA
    • glare sens
    • no irritation/scarring
  25. What are the signs of PMD?
    • ATR ast
    • thinning 4-8o'clock
    • epith intact
    • NO vogt's striae or Fleisher's ring
  26. What are the features of the ast seen in PMD? (3)
    • increasing
    • severe
    • ATR ast
  27. Where is thinning seen in PMD?
    • inf
    • 4-8oclock
    • ~1-2mm wide
  28. What are Vogt's striae?
    vertical collagen tension lines on the post corneal stroma that disappears with external pressure on the globe
  29. What is Fleischer's ring?
    partial or complete deposition of iron in deep/basal epithelial cells at the peripheral cornea
  30. DDX for PMD
    • Mooren's ulcer
    • Terrien's marginal degeneration
    • Keratoglobus
    • KC
  31. What is mooren's ulcer? (3)
    • painful
    • rapidly
    • progressive inflammation
  32. What is Terrien's marginal degeneration? (2)
    • mostly superior cornea affected
    • with lipid deposition
  33. What is the prevalence for KC? (3) i.e. 1 in _________; which gender is more prevalent; what age range
    • 1:2000 (range)
    • M>F
    • late teens to mid 40s
  34. Describe features of KC in 3 words
    progressive or stable
    inflammatory or non-inflammatory
    d________
    • progressive
    • non-inflam
    • degenerative
  35. KC is
    corneal steepening/protrusion
  36. Where do we see thinning/steepening in KC?
    central or para-central
  37. KC is caused by changes in
    biomechanical properties
  38. What are the main symptoms of KC? (5)
    • refractive error changes
    • irregular ast
    • decreased contrast sensitivity
    • myopia
    • corneal sensitivity
  39. What are the associated risk factors of KC? (5)
    • UV exposure
    • Allergies/atopy --> vigorous eye rubbing
    • poory fitting CL
    • genetic background/ethnicity
    • inflammation
  40. What is the main indicator for penetrating keratoplasty and at what %?
    • KC px
    • ~30%
  41. What are the symptoms of KC? (6)
    • progressive blurring, distortion (mostly bilateral, one eye earlier)
    • photophobia, glare, ocular irritation
    • monocular diplopia/polyopia
    • BCVA may be normal early with decreased CS
    • axis shift and irregular ast
    • CLs more difficult to fit, uncomfy
  42. Signs of KC (10)
    • steep and irregular changes in the corneal curvature
    • munson' sign
    • Vogt's striae
    • Fleischer's ring
    • Apical ant stromal scarring
    • scissors reflex with ret
    • Charleux oil drop with ophthal
    • Rizzuti's sign
    • Prominent corneal nerves, decre sens
    • breaks in descemet's and hydrops
  43. Define atopy
    a syndrome characterized by the tendency to be "hyperallergic"
  44. What is Munson's sign?
    profile of the cornea seen on the lower lid when px looks down with the upper lid held away
  45. What are vogt's striae? (3)
    • deep stromal striae
    • vertical lines related to tension in collage layers due to apical stretching
    • can involve deep stroma and descemet's membrane
  46. What is Fleischer's ring? (5)
    • iron ring at the base of cone in KC
    • appears black with blue light
    • can be partial or complete
    • mainly collected along the basal epithelium
    • severe if ions along the entire epith
  47. Features of apical anterior stromal scarring
    • may be related to CL wear e.g. rubbing of CL on apex
    • KC fitting = light pressure on apex; excess --> scarring
  48. What is the Charleux oil drop?
    • oil drop reflex with ophthalmoscope
    • internal reflection of light withing steeper region of the cone
    • can be seen in SL
  49. What is Rizzuti's sign?
    steep cone focusses light shone from temporal edge of eye as a focal band on the nasal iris
  50. Features of prominent corneal nerves
    • decreased sensitivity
    • thickened nerves
    • diff distbn/density
    • seen with confocal microscope
  51. Compare normal corneal nerve organisation with KC
    • normal: crop shape whorls, straight, dense
    • KC: concentric pattern at base of steepening, tortuous, less dense
  52. In the Amsler-Krumeich grading, mild, moderate and severe are classified by:
    • <48D
    • 49-54D
    • >54D
  53. How are corneal ectasias detected clinically?
    • placido disc
    • keratometry
  54. What are the newer imaging possibilities for corneal ectasias?
    • ORBSCAN - SL and topography
    • PENTACAM - ant segment tomography, 3D images of the cornea
    • confocal microscopy
  55. What are the corneal topography types?
    • A. Nipple
    • B. Oval
    • C. Globus
  56. What are the features of nipple-shaped topography?
    • small
    • near central ectasia
    • <5mm in cord dia
  57. What are the features of oval-shaped topography?
    • sup cornea normal
    • steepening in the inf
  58. What are the features of the globus-shaped topography?
    • affects the largest are of the cornea
    • area above the middle is affected 
    • rare
  59. How do you assess the clinical sign of apical thinning?
    • fine slit beam
    • assess BE
    • assess direct cross section

What would you like to do?

Home > Flashcards > Print Preview