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Clinski > eeeeee > Flashcards

eeeeee Flashcards

1
Q

Imbert fick law:

A

IOP = (force + Tear-film attraction - Corneal resistance) / Area
- from P=F/A equation on perfect sphere

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2
Q

Ishihara test plates:

A

Demo plates (4)
Transformation plates
- Colours on confusion loci present different numbers
Vanishing plates
- Confusion loci > loss of any number
Hidden plates
- Number is crowed by confusion loci (only seen by CVD)
Diagnostic plates
- One number is not seen by protan (red) or deutan (purple)
- Inaccurate

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3
Q

Colour vision test result interpretation:

A

Ishihara: Mono or Bino
- <=2 (normal)
- >2 on plates 2-15 (RG defect) 2% false pos.
- >4 Certain CVD
Medmont C-100:
- -1<>+1 (normal)
- <-1 (Protan)
- >+1 (deutan)
HRR:
- 2 on screening plates (probable CVD)
- >2 (definite CVD)
1. Classification plates 1>5 (mild), 6>8 (medium), 9>10 (severe)
Farnsworth D-15:
- Pattern of proten, deutan, tritan, rod monochromacy
- requires 2 major crossings (space of more than 2 caps)

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4
Q

Colour vision procedure:

A
  1. VA > Ishihara
  2. HRR / Medmont C100 / Farnsworth D-15
  3. L’anthonys desat. D-15
    Educate Px on CVD
    - Document and record Fx
    Counselling/support groups/color identifying apps
    Regular follow-ups
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4
Q

OCT evaluation for glaucoma:

A

RNFL thinning <80 microns
GCL thinning <70 microns
ONH
- CDR >0.5, or asymmetry of 0.2
- NRR (ISNT/Notching/Localised thinning)
- PPA (asymmetrical, pronounced B-PPA)
- Drance haem
- Vertical elongation
- Laminar dot sign

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5
Q

CVD causes:

A

Protan/Deutanopia: X-linked recessive
- Red (L-cones), or green (M-cones) completly missing
- P/D-anomaly > mild form where photopigments are altered
Tritanopia: Autosomal recessive
- Blue (S-cones)
Acquired:
- Cataract (contrast loss)
- Glaucoma/MS (blue yellow loss)
- AMD (contrast loss)
- DR (blue/yellow > red/green)
- RP

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6
Q

Keratometry:

A

Videokeratoscopy (placido discs) provide Corneal topography map
- Axial/tangential power/curvature
- Required for fitting CLs and detecting corneal diseases
- Pupil/cornea size

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6
Q

Ocular biometry:

A

Pachymetry: Ultrasound / OCT
- U/540um
Ultrasound biometry:
- A-scan: Axial length
- B-scan: RD, Tumors
OCT:
- Ant: CCT, Angle, Iris
- Pos: everything else

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7
Q

CL wearer clinic procedure:

A

Hx:
- PC, GH, CL compliance/use, lens handeling
VA (mono/bino)
Lens fit (Stain for RGP)
Ant. assessment without lens: (observe Px handeling lens)
- Stain+wratten
- Ocular surface > DEWS grading
- Tear assessment
- Lid eversion

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7
Q

Soft contact lens assessment:

A

15 minute settling period
VA + over refraction
Corneal coverage (TD) 1mm over limbus
Lens centration/position
Lens movement
- Primary blink (0.2-0.5mm)
- Up/horizontal gaze
- Push-up
Edge alignment
Lens surface biocompatibility (wettability)
Toric alignment
- Left of vertical requires adding to axis, otherwise:
- Acuvue oasys for astig (accelerated stabilisation design)
- Biofinity toric (Peri-ballast)

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7
Q

Soft contact lens selection & example order:

A
  1. Material > Spherical/aspheric
    - Hydrogel: ^comfort for short term wear
    - Silicone hydrogen: ^O2 permeability for long term wear
  2. SCL 2mm larger than HVID (keratometry/slit)
  3. Base curve 0.6mm flatter than mean K (keratometry)
    - Flat K + 0.6mm
  4. BVP from refraction
    • 4D > +0.25
    • 6D > +0.50…
      - If > 1 DC, use toric
      Example order: Acuvue Oasys 8.4/14.0/-2.00D (BC/TD/BVP)
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8
Q

RGP parameters and rule of thumb:

A

TD 2mm less than cornea (9-9.8mm)
- BOZD (7.0-8.5) increases with TD, must be 1.5mm larger than pupil
BOZR (7.80-7.70mm)
- Fit to flattest (greater value) K meridian
- Increased by 0.5mm per 1DC
- If >2.5DC, consider toric back surface
BVP: 0.05mm increase in BOZR from corneal curvature = 0.25D tear lens power
- Tear lens power - refractive error
Design/brand/Material
Centre/edge thickness
ALTERING LENS PARAMETERS RULE OF THUMB (to retain stain pattern)
- Increasing BOZD by 0.5 requires flattening BOZR by 0.05
- Flattening (increasing) BOZR by 0.05 decreases tear power by 0.25

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8
Q

Fused cross cylider:

A

At Habitual
-0.50DC at 90 to project hortizontal lines anterior
- Clearer horizontal lines > lag of accom. > add plus lenses till equal
This seperates the meridians in the interval of strum

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9
Q

Clinical tests for children:

A

—Visual Acuity—
Visually evoked potentials: 0-2
Optokinetic nystagmus drum: 0-2
Keeler grating acuity cards: 0-2
Lea symbols: 2-5
- Match cards, threshold everything is a circle
- 3m (distance), then 25cm (near)
Kay pictures: 2-5
Tumbline E/Landot C: 4-5
- Broken wheel is a fun variation of landot C
Letter matching/Snellen: 5+
—Binocularity—
20PD BO > motor fusion
20PD BI > fixation preference
Red reflex: Symmetrical reflex from ophthalmoscope
Steriofly
—Cyclopentolate—
- Check RAPD and PERRLA prior
Retinoscopy: expect 1D of hyperopia
- Provide full prescription
- Atropine stronger eye in case of strab
Mohindra retinoscopy: if cannot cyclo
- ret at 50cm, and subtract 1D

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10
Q

Cause of deviations:

A

Comitant:
- Congenital strabismus (Tropia)
- Accomodative esotropia (hyperopia)
- Intermittent exotropia
- Genetic/anatomical factors
Incomitant:
- CN 3/4/6 palsy
- TED
- MG
- Chronic progressive external ophthalmoplegia

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10
Q

DED Hx and risk factors:

A
  • Severity
  • Assoc. (sjrogrens cotton mouth)
  • Onset (infection/trauma)
  • Vision change (blur on blink)
  • Uni/Bilateral
  • Itchy/pain
  • CL wear
  • Systemic conditions
    DED risk factors:
    ^age, Female, asian
    MGD, pterygium, DM
    Sjogrens
    CLs
    Environment
    Antihistamines
11
Q

Clinical management of phoria:

A

Sheards criterion > Opposing fusional reserve must be at least twice the phoria
- If 6 exo
- PFV > 12 BO, phoria is compensated
- PFV = 8 BO, a 2 BI lens in required (is now a 4PD exo)
Percival’s criterion > PFV+NFV = 10
- PFV ~20 BO
- NFV ~ -10 BI

11
Q

Incomitant deviation clinic:

A

Hx:
Diplopia: U/new acquisition
- Horizontal/vertical
Amblyopia: U/new
Head position change: U/long standing
1. Cover test: measure deviation of each eye while the other if fixing > Greater deviation in non paretic eye (herring’s law of equal innervation)
2. Hess screen: R/G dissociation > R fixation and G pointer > Px marks where the fixation light is
1. Smaller chart is parietic eye
2. Degree of disparity gives angle of deviation
3. Parks 3 step: determines parietic muscle from Rectus or Oblique muscles
1. Which is hyper (Hyper eye’s IR/SO, or Hypo eye’s IO/SR)
2. Worse on R/L gaze (Gaze’s IR/SR, or opposite’s IO/SO)
3. Worse on R/L tilt (Tilt’s SR/SO, or opposite’s IO/IR)

11
Q

Dissociated phoria tests:

A

Cover-uncover:
- Tropia > uncovered eye moves
- Phoria > covered eye moves when uncovering
Alternating cover:
- Determines degree of phoria
Phi phenomenon: subjective
Prism cover test:
- amount of prism required to remove phoria or tropia
Maddox rod: Vertical streak (horizontal phoria) or horizontal streak for vertical
- Used in case of suppression
- Eso if Px sees line left of light source
Vone graefe: 6BU and 15BI
- Decrease horizontal OR vertical to determine horizontal or vertical phoria
Howel phoria card

12
Q

DED management:

A

DEWS step 1:
- Educate: DED lifelong
- Environment (masks, computer time)
- Diet change
- Cease offending medications
- Ocular lubricants
- Lid hygiene, warm compress
- 45’ towel, reheated every 2 mins for 10 mins
Step 2:
- Non-preservative tears
- Tea-tree oil for demodex
- MG expression
- short term cortico.
- FML QID shown to reduce symptoms and increase goblet density
- Immunomodulatory drugs
- Ciclosporin to prevent T-cell activation
Step 3:
- Autologous serum drops
- BCL
- Soft > comfort
- RGP scleral > tear repository
Step 4:
- Long term cortico.

12
Q

Fixation disparity:

A

Vergence error within panums fusional area <10minutes of arc
- causes strain, asthenopia, poor near/distance (exo/eso)
Mallet unit test: polarized septum dissociation
- Each eye sees either top of bottom line
- Prism added to align lines

13
Q

Measuring fusional vergence:

A

Prism bar until blur/break/recovery
Risley prism on phoropter is easier
- BO > Convergence
- BI > Divergence
- BU/BD if needed
Repeat for NFV

13
Q

Vergence facility:

A

3BI/12BO flippers, cycle once 40cm target cleared
Normal > 15cmp
Poor BI > convergence insuf
Poor BO > Divergence insuf

14
Q

AC/A:

A

Gradient AC/A: (PD deviation with lens - Prism deviation without)/Lens power
- The difference between values divided by lens required to create deviation
Calculated AC/A: AC/A = (Convergence demand + near esophoria - distance exophoria)/Accom. demand
- Stimulus to accommodation at 40cm = 2.5
- Convergence stimulus at 40cm = 15

14
Q

Work-up of ocular trauma:

A

Abrasion or perforation
- VA
- seidel sign (perforation)
- Lid eversion > double lid eversion
- Lid laceration / Conj. abrasion
- Anterior assessment
- Corneal abrasion/perforation, FB
- Uveitis, Hyphema, Angle recession, Lens subluxation
- Posterior assessment (dilate for metal on metal)
- intraocula FB
- Anaesthetic > 25-guage needle removal > alger brush
- Chloramphenicol 0.5% QID, Ketorolac (NSAID for pain) 0.5% QID, BCL
Chemical
- copious saline > CL removal
- pH strip (every 5min)
- Cortico. / antibiotics / lubrication
- BCL / IOP management

14
Q

Tests for suppression:

A

Worth lights: RG filter
- Red on RE, Green on LE
- Target has 2G, 1R, 1W light
- 4 Dots > normal
- 3 green > RE suppression
- 2 red > LE supression
- 5 dots > uncrossed diplopia
Stereopsis
- Randot
- Titmus fly

15
Q

Response to long answer question:

Px presents, what do you do

A
  1. List reasons for visit (Hx)
  2. Tentative diagnosis
  3. Plan exam
  4. Evaluate results
  5. Assess extra tests
  6. Review reasons for visit
  7. Form diagnosis
  8. Evaluate treatment options
  9. Present management
  10. Provide patient information

Clinski (8 decks)

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