OSCE 2

Question 2

Gonio Px Explanation:

Answer 2

• This test will assess the hidden angle on the front of your eye
• I’ll need to place a contact lens on you
• I’ll drop an anesthetic in your eye to numb your cornea
  
  • Are you pregnant, breast-feeding, or allergic to anything
  • Do not rub your eyes for 30 minutes to avoid scratches
• Do you consent to this test being performed

Question 3

Gonio preparation:

Answer 3

1. Disinfect gonioprism retrospectively
   
   1. Clean via soap (surfactant)
   2. Saline rinse
   3. 1:10 bleach soak > 5min
   4. Saline rinse > 1min
   5. Air dry, disposable cloth
2. Alcohol swab gonio prior to examination
3. Prepare slit lamp
   
   1. Disinfect (alcohol)
   2. Focus eyepiece (calibration bar)
   3. Set PDs
   4. low mag (10x)
   5. 2mm wide, 4mm high
   6. beam luminance straight on
   7. decrease room and beam luminance

Question 4

Gonio corneal check:

Answer 4

1. Position Px
   
   1. Lower chin rest > lower than canthus
2. Instill NaFl
3. Assess cornea on down/up gaze
   
   1. note abrasions
   2. Otherwise NAD

Question 5

Gonio insertion:

Answer 5

1. Anesthetic drop
   
   1. Advise not to rub eyes for 30 minutes
2. Fill 2/3 lens with coupling solution “poly-gel”
   
   1. “This solution removes bubbles, it might run down your cheek”
3. Position gonio
   
   1. Thumb-shaped mirror at 12’
   2. Held between thumb and index
4. “look down please”
   
   1. Pull superior lid w/left thumb
5. “Look up please”
   
   1. Retract lower lid w/right middle finger
6. Position gonio on lower lid
7. “Look straight ahead please”
   
   1. Pivot prism until lens in contact with globe
   2. Bubble formation requires reset
8. release lids while holding lens in place
   
   2. pressure on cornea slightly (avoid visible wrinkles)

Question 6

Gonio assessment procedure:

Answer 6

1. Vertical parallelepiped 2/4mm
   
   1. lower brightness reduces pupillary action
2. Sweep pupil > iris
   
   1. Note elevations/abnormalities
3. Sweep angle; note seen structures
   
   1. Schwalbe’s line
   2. Trabecular meshwork
      
      1. Ant. is clear
      2. Pos. is pigmented
   3. Scleral spur
   4. Ciliary body band
   5. Iris processes
4. Tilt lens towards thumb mirror to see more
5. Rotate lens 90’
   
   1. both hands to spin lens
   2. Rotate illumination perpendicular to mirror
6. Repeat assessment for all 4 angles
7. Remove lens
   
   1. Rock lens back and forth
8. Examine corneal integrity

Question 7

Gonio recording:

Answer 7

In each X quadrant
- Record most posterior structure
- CBB
- SS
- TM
- SL
- Record NAD/other abnormalities
- Record pigmentation of TM 0-4(dark)
- normally 2

Question 8

CL fitting procedure:

Answer 8

1. BVS over-refraction
   
   1. Push/Pull method
   2. +1 blur check
2. Coverage
   
   1. 1mm beam at limbus
   2. CL should extend 1mm over limbus
3. Centration
   
   1. 1mm beam at 4 quadrants
   2. CL should have same coverage
4. Movement on primary
   
   1. direct focal illumination, wide beam
   2. “please perform a natural blink”
   3. measure motion from inferior CL
5. Movement on up-gaze
   
   1. “look up 30’ then blink”
   2. Measure motion from inferior CL
6. Lens lag on lateral gaze
   
   1. measure coverage on temporal side
   2. ‘look nasally’
   3. measure change in coverage
   4. Measure coverage on nasal side
   5. “Look temporally”
   6. Measure change in coverage
7. Movement on push-up
   
   1. push on inf. lid and release
   2. note resistance to motion and speed of recovery
   3. Grade 0-100% tightness
8. Rotation
   1. note in degrees anti-/clockwise from inferior position
9. Surface and edge quality
   
   1. Diffuse focal illumination, wide beam
   2. assess alignment of lens with peripheral cornea
   3. note crimping of conj. BVs or edge standoff
   4. otherwise NAD

Question 9

Assessment of loose fitting lens:

Answer 9

Uncomfortable
VA worsens post-blink
Poor centration: displaced inferiorly
Edge alignment: bucklink/folding
Motion on blink: >0.5mm
Push-up: easy motion w/erratic recovery

Question 10

Assessment of tight fitting lens:

Answer 10

Comfortable
VA improves on blink
Full coverage: little sag
Edge alignment: limbal nipping > hyperemia
Motion on blink: none
Push-up: resistant motion w/slow recovery

Question 11

Subjective refraction procedure:

Answer 11

1. Inform Px of test
2. Measure PD’s
3. Assess Unaided VA
4. Retinoscopy
   * Against add minus
5. BVS
   * Focus on last line read
   * Push/Pull
   * Blur check
6. JCC
   * Axis > Power > Axis
   * Chase red
   7 Blur check (+1)
7. Binocular balance

Question 12

Contact lens script

Answer 12

• This session will assess the fit of your contact lens
• I will also place a ridgid gas permeable lens in your eye
• to do this I’ll need to use an anaesthetic and touch your face
• Is that all good?
• Are you pregnant, breast feeding or allergic?
• Im soaking the RGP, please tilt your head forward and look down > Up > straight
• place lens on
• To remove the lens I need you looking straight while I push on your lids
• Assessing the fit of the SCL
• Coverage is good 1mm
• Looking left/Right/Down
• Lag is good
• Looking straight, then Left/Right, then straight
• Movement is good
• Looking straight, I’ll just push on your eyelid
• Toric assessment is good