OSCI1

Question 1

Cleaning GAT

Answer 1

1. Clean w/mild PH detergent/soap
   
   1. Surfactant B&L lens cleaner
2. Rinse with saline
3. Soak in sodium hypochlorite (5000ppm) for 10mins
   
   1. 1/10 bleach solution
   2. change solution if touched by hand
   3. soap clean solution containers daily
4. Rinse with saline/distilled water
5. Air dry / Sterile cloth dry

Question 2

GAT procedure

Answer 2

• Alcohol wipe rests
• NaFl stained examination
  
  • Assess healthy cornea
• Place tono probe on mount
  
  • set doubling at horizontal meridian
• Wide slit (max luminance)
  
  • 45-60(deg) from probe temporally
  • 16x mag
• Move probe into visual axis
  
  • Set measuring drum to 10mmHg
• Instill anesthetic
  
  • 0.5% alcaine
  • Px not to rub eyes for 15mins
  • Follow with another NaFl stain
• Note Alcaine 0.5%, one drop, at time
  1. “Place head in rest, focus straight ahead and slightly upwards”
• Motion probe forward until contact is made
  
  • Limbus will illuminate blue
• change measuring drum to have rings barely intersecting
  
  • Increasing forward motion until size of rings doesn’t change
• note final measure
• re-examine cornea for complications
• clean and disinfect prisms after use

Question 3

OSCE GAT explanation:

Answer 3

1. Hi, my name is Dyllan
2. This test will assess your intraocular pressures using a Goldmann Applanation Tonometer
3. It works via the Imbert-Flick law, essentially reading your eyes internal pressure by pushing against the front part of your eye
4. This measurement helps me gauge that your eye is healthy and circulating fluid properly
5. This probe has been disinfected
   
   1. Cleaned with a mild surfactant
   2. Rinsed with saline
   3. Soaked in sodium hypochlorite 5000ppm for 10 minutes (1:10 bleach)
   4. Rinsed with saline
   5. Air dried
6. Do you consent to this test being performed?
7. Are you pregnant, or know of any allergies you may have to medication

Question 4

Distance PD assessmnet

Answer 4

1. “I’m checking the distance between your eyes to ensure lenses will be in the right position”
   - face Px at 40cm
   - rest PD ruler on Px nose bridge
2. “keep focus on my open eye”
   - Close right eye
   - Align Zero point of ruler with center (or edge) of Px Right eye
   - Close Left eye (open right)
   - Note measure of center (or edge) of left eye

Question 5

Subjective refraction OSCE procedure:

Answer 5

• Measure PDs
• Set phoropter (Clean, PDs, tilt, vertex)
• Obtain monocular unaided VA
  1. “Ill place lenses Infront of your eye to find what will give you the best vision”
  2. “There are no wrong answers, everything is double checked”
• place tentative script in
• Occlude left eye; assess right eye
• Obtain best vision sphere
  
  • End check +1.00 blur/Duochrome
• Obtain Cyl axis via Jackson Cross-Cylinder
• Obtain Cyl w/JCC
• Repeat BVS
• Measure VA

Question 6

BVS Plus/Minus:

Answer 6

• Add +0.25DS
  1. “Are the letters clearer, more blurred, or the same”
  
  • add plus if clearer
  • Keep initial plus in trial frame to avoid accomodation
• Continue until blur
  
  • Keep most plus
• Add -0.25
  2. “does this help you read more letters”
• continue until VA does not improve
  
  • keep most plus
• Perform +1.00 blur check / Duochrome check

Question 7

Maximum plus to maximum VA technique

Answer 7

• Add +1.00DS to RE
  
  • 4 lines should be lost (including read line)
    
    1. “Let me know which lens is clearer”
• Change power until 4 lines of acuity is lost (Fogged)
• Reduce fog by 0.25DS
  
  • ensure VA improvement
• Cease once no improvement occurs
• Perform +1.00 blur/Duochrome check

Question 8

JCC:

Answer 8

• JCC set to straddle correcting axis
  
  • “A” mark aligns with set axis
    
    1. “Ill show you two lenses, both may be blurry, tell me which is clearer, or if they’re the same”
• rotate towards preferred axis until they appear the same
• Proceed to power determination
  Power determination:
• JCC set to have dots on, and 90(deg) from correcting axis
  
  • “P” mark aligns with set axis
• Note which lens feels clearer
  
  • “Red dot” > Add Cyl
  • “White dot” > Remove Cyl
• For each 0.50DC changed, balance with 0.25DS

Question 9

SIO procedure:

Answer 9

1. Set up
   
   1. Illumination in-line with scope
   2. Parallelepiped 2mm, height equal to pupil
   3. low intensity
   4. low mag (10x)
2. Focus on the iris, beam centre of pupil
3. place lens 4mm parallel to cornea
4. Pull lamp back until retina focuses
5. increase mag / illumination as needed
   
   1. mitigate reflections by tilting illumination system
6. Evaluate ON
   
   1. Size / Shape / Colour / Depth
   2. CDR
   3. NRR > ISNT rule
   4. Abnormalities
7. Assess arcades
   
   1. Tilt lens with lamp motion
   2. Colour / Tortuosity of BVs
   3. AV ratio
8. Pull back slightly > assess pos. vitreous
9. Assess 8 gazes of periphery

Question 10

SIO dialogue:

Answer 10

1. I’m assessing the health of your eye with a microscope and lens held near your eye
2. The lamp will be bright, lmk if you’d like a break
3. Please look at my ear, if it helps to close your other eye just look forward
4. I’ll need to rest my hand on your cheek, is that okay
5. Blink normally, just try to hold your eyes open wide
6. Lmk if the lens touches your lids
7. Please look (8 directions)
8. While looking down, ill pull your lid up a bit, blink as much as you need, lmk if im pushing too hard

Question 11

SIO recording:

Answer 11

1. Vitreous > NAD (no abnormalities detected)
2. ONH
   
   1. Disc margins distinct
   2. Average size
   3. No PPA
   4. NRR uniform, ISNT obeyd
   5. CDR 0.4H, 0.4V
   6. No abnormalities
3. Clear NFL
   
   1. ILM sheen noted
4. BV normal
   
   1. AV ratio of vessels near disc 2:3
5. Posterior pole NAD
6. Macula NAD