O2B Gonio

  1. What is gonioscopy?
    procedure to view the anterior eye using a gonioscope
  2. What can you see with gonio when dilated/not dilated?
    • anterior chamber angle without dilation
    • peripheral fundus when dilated
  3. What are the reasons to evaluate the anterior angle chamber?
    • glaucoma
    • determination of likelihood of angle closure
    • examination of abnormal structures in angle
    • iris tumours
    • ocular trauma
    • Pseudoexfoliation syndrome
    • Pigment dispersion syndrome
    • Rubeosis irides
  4. What are the contraindications for gonio?
    • Corneal abrasions or ocular trauma
    • Hyphaema¬†
    • Lacerated or perforated globe
    • Following ocular surgery including cataract surgery
    • Recurrent corneal erosion syndrome
    • Corneal keratopathy
    • Anterior uveitis-iritis including patients with known recurrent attacks
  5. What are the 6 layers visible with the anterior angle?
    • schwalbe's line
    • trabecular meshwork
    • schlemm's canal
    • scleral spur
    • ciliary body
    • iris
  6. What are the characterisitics of schwalbe's line?
    • fine white line- not always visible
    • indicates termination of descemet's membrane
    • line becomes pigmented with age
  7. what is psuedoexfoliation?
    accumulation of granular amyloid-like fibres found in schwalbe's line
  8. What are the characteristics of the trabecular meshwork?
    contains 2 distinct bands- non pigmented anterior line, pigmented posterior line
  9. What are the characteristics of schlemm's canal?
    • not visible
    • only seen if contains blood
  10. What are the characteristics of the scleral spur?
    • defined light coloured band
    • point of attachment ¬†of ciliary body to sclera
  11. What are the characteristics of the ciliary body band?
    • darker brown/grey uniform colour
    • if visible- angle is very wide
  12. What is the characteristic of the image in gonio?
    inverted but NOT reversed
  13. Why is the goldmann lens gonio limited?
    • 4 mins
    • needs coupling fluids
    • corneal dehydration
  14. What are the advantages of using a goldmann?
    • Versatility
    • Gonioscopic angle evaluations
    • Direct posterior pole examination through contact
    • Peripheral retinal examinations extending to ora if good dilation
  15. What are the disadvantages of using a goldmann?
    • corneal dehydration
    • only 1 view of the angle at a time
    • need to rotate for view
    • scary for px
  16. Zeiss type advantages?
    • 360 view without rotation
    • no coupling fluids needed
    • allows indentation gonio
    • less imposing for px
  17. Zeiss type disadvantages?
    • view less mag and sharp
    • harder stability
  18. What is the Schaffer classification of anterior chamber angles?
    • 0/0/iridocorneal contact present, apex of corneal wedge not present
    • 1/10/schwalbe line present
    • 2/20/only trabeculum present
    • 3/25-35/scleral spur present
    • 4/35-45/ciliary body easily visible
  19. What is the modified Schaffer classification of anterior chamber angles?
    • narrow angle/<10/less than 1/3 of trabecular seen
    • intermediate/10-20/entire trab seen
    • wide/>20/ciliary body present
  20. How can you tell that the angle is acutally closed?
    if beam from iris and posterior cornea are coincident
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O2B Gonio