OSCE 2 Flashcards
Gonio OSCE procedure:
- Instruct purpose and obtain consent
- Hand hygiene and equipment disinfection
- Slit lamp set-up
- beam width/height
- Light intensity
- Magnification
- Check corneal integrity
- Instill anesthetic drop
- Time, name, conc, dosage
- Safely inset gonio
- Clear view of 4 angles
- Describe structures
- remove gonio safely
- check corneal integrity
- record findings in correct orientation
Gonio Px Explanation:
- 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
Gonio preparation:
- Disinfect gonioprism retrospectively
- Clean via soap (surfactant)
- Saline rinse
- 1:10 bleach soak > 5min
- Saline rinse > 1min
- Air dry, disposable cloth
- Alcohol swab gonio prior to examination
- Prepare slit lamp
- Disinfect (alcohol)
- Focus eyepiece (calibration bar)
- Set PDs
- low mag (10x)
- 2mm wide, 4mm high
- beam luminance straight on
- decrease room and beam luminance
Gonio corneal check:
- Position Px
- Lower chin rest > lower than canthus
- Instill NaFl
- Assess cornea on down/up gaze
- note abrasions
- Otherwise NAD
Gonio insertion:
- Anesthetic drop
- Advise not to rub eyes for 30 minutes
- Fill 2/3 lens with coupling solution “poly-gel”
- “This solution removes bubbles, it might run down your cheek”
- Position gonio
- Thumb-shaped mirror at 12’
- Held between thumb and index
- “look down please”
- Pull superior lid w/left thumb
- “Look up please”
- Retract lower lid w/right middle finger
- Position gonio on lower lid
- “Look straight ahead please”
- Pivot prism until lens in contact with globe
- Bubble formation requires reset
- release lids while holding lens in place
- pressure on cornea slightly (avoid visible wrinkles)
Gonio assessment procedure:
- Vertical parallelepiped 2/4mm
- lower brightness reduces pupillary action
- Sweep pupil > iris
- Note elevations/abnormalities
- Sweep angle; note seen structures
- Schwalbe’s line
- Trabecular meshwork
- Ant. is clear
- Pos. is pigmented
- Scleral spur
- Ciliary body band
- Iris processes
- Tilt lens towards thumb mirror to see more
- Rotate lens 90’
- both hands to spin lens
- Rotate illumination perpendicular to mirror
- Repeat assessment for all 4 angles
- Remove lens
- Rock lens back and forth
- Examine corneal integrity
Gonio recording:
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
CL fitting procedure:
- BVS over-refraction
- Push/Pull method
- +1 blur check
- Coverage
- 1mm beam at limbus
- CL should extend 1mm over limbus
- Centration
- 1mm beam at 4 quadrants
- CL should have same coverage
- Movement on primary
- direct focal illumination, wide beam
- “please perform a natural blink”
- measure motion from inferior CL
- Movement on up-gaze
- “look up 30’ then blink”
- Measure motion from inferior CL
- Lens lag on lateral gaze
- measure coverage on temporal side
- ‘look nasally’
- measure change in coverage
- Measure coverage on nasal side
- “Look temporally”
- Measure change in coverage
- Movement on push-up
- push on inf. lid and release
- note resistance to motion and speed of recovery
- Grade 0-100% tightness
- Rotation
1. note in degrees anti-/clockwise from inferior position - Surface and edge quality
- Diffuse focal illumination, wide beam
- assess alignment of lens with peripheral cornea
- note crimping of conj. BVs or edge standoff
- otherwise NAD
Corneal wedge structures Ant > Pos
- Schwalbe’s line
- Anterior opaque line
- point where the 2 reflections meet
- Junction between posterior cornea (decemet’s) and trabeculum
- Can’t be visualized usually
- Trabecular meshwork
- Ant. is pale (next to Schwalbe’s line)
- Pos. is u/pigmented (heavy w/pigmentary dispersion syndrome)
- Schlemm’s canal in TM can only be seen if filled with blood
- Scleral spur
- Narrow dense shiny band
- pos. to TM, most ant. part of sclera
- Visibility indicates open angle (wont close)
- consistant across different eye colours
- Ciliary body band
- Brown/Grey/Pink band
- narrower in hyperopic eyes /Vice versa
- Iris processes may partially cover
- Iris processes
Van Herick assessment:
Illumination straight on
observation 60’ from illumination
Narrow beam at edge of limbus
Note ratio of Shadow:Beam
- Grade 4 “Wide” 1:1
- Grade 3 “Open” 0.5:1
- Grade 2 “Narrow” 0.25:1
- Grade 1 “Closed” <0.25:1
OSCE CL rubric:
- Instruct Purpose of exam
- Hand hygiene
- Instruct throughout exam
- Set up slit lamp width/height/intensity/mag
- Determine BVS over-refraction
- VA each eye also beforehand
- assess/narrate centration and coverage of CL
- assess/narrate movement of CL
- Push up test
- Assess/narrate rotation of CL
- Explain how to correct for lens rotation
- Record CL prescription in standard terminology
- BC
- TD
- BVP (-ve cyl form)
- State if the CL is good fit
- note next trial soft CL to consider
- Name, BC, TD, BVP
Ideally fitting CL:
- comfortable
- Centered (no difference between quadrants)
- 0.2-0.5 mm on blink
- Full coverage on all gazes
- regular edge alignment w/conj.
- stable vision
Assessment of loose fitting lens:
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
CL orderings:
Tighter lens:
Easyvision Umere Toric
BC 8.6
TD 14.3
BVP as Px script
Looser lens:
EasyVision Linarial Toric
BC 8.6
TD 14.5
BVP as Px script
Assessment of tight fitting lens:
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