EXAM FIRST HALF Flashcards
(122 cards)
1
Q
Components of case history
A
PC: presenting complaint POH: ocular history FOH: family ocular history FMH: family medical history GH: general health + medication VT: Visual tasks (hobbies/driving)
2
Q
LOFTSEA In assessing PC
A
Location: R/L eye, which VF Onset: Time frame Frequency: how often Type: how bad are symptoms, type of pain Self-treatment: What helps symptoms Effect: how does this affect lifestyle Associated signs and symptoms: relationship to alternate disease
3
Q
Screening questions in PC:
A
How is D/I/N vision Age/effect of correction Sore/red/itchy eyes Flashing lights/floaters Headaches Double vision
4
Q
POH questions:
A
LEE: last eye examination
Trauma/disease history
Surgery
5
Q
Family ocular history questions
A
AMD Glaucoma High myopia Strabismus Retinal degenerations/detachment
6
Q
Family medical history questions
A
Diabetes Hypertension Cardiovascular disease Neurological disease Inflammatory disorder
7
Q
General health questions
A
ROS: review of systems (function of body systems)
Past medical history: illness/injury/surgery
- Blood pressure
- Diabetes
- Cholesterol
Alcohol/tobacco
8
Q
Visual acuity measurement
A
Detection: recognition on size change
Resolution: recognition on separation distance
Recognition: symbol determination
Localization: angle of displacement of components
9
Q
Snellen fraction
A
(test distance)/(optotype)
Optotype = distance from chart where letter subtends 5minute arc (5/60 degree) on retina
10
Q
Snellen chart optotypes, from 4.5
A
4.5, 6, 7.5, 9, 12, 36, 60
11
Q
Snellen letter size on retina
A
Letter stroke/space takes up 1/5 of total letter area and corresponds to 1min arc
2min arc = 1 cycle of sine wave representing resolution
12
Q
Minimum angle of resolution: MAR and LogMAR
A
Snellen reciprocal E.g. 6/60 = 60/6 = MAR 10 LogMAR is just the log of this number 6/6 = MAR 1 = LogMAR 0 Each letter read = 0.02 logMAR
13
Q
Cycles per degree and snellen letter
A
2min arc = 1 cycle of sine wave; 60min arc = 1 degree
30 cycles per degree
CPD = 30 x Snellen decimal (6/12 = 0.5)
14
Q
Refraction steps, from VA to prescription
A
Preliminary tests + VA PD measurement Phoropter setup Retinoscopy Best vision sphere + endpoint Cylinder refinement + endpoint Binocular balance Near vision assessment Prescription
15
Q
Prentice Rule
A
P = c.F P = prism diopters C = decentration in cm F = power of lens in given meridian
16
Q
3 measurements on frame 52 [] 18 - 135
And how to find frame PDs:
A
And how to find frame PDs: 52 = lens diameter 18 = bridge width 135 = arm length Bridge + lens diameter = frame PD
17
Q
When retinoscopy is useful:
A
Children
Nonverbal adults
Latent hyperopes
Immobile Px
18
Q
Preliminary/screening test sequence:
A
D/N VA Cover test NPC Accommodative amplitude (if needed) Stereoacuity (if needed) Amsler grid (if needed) Color vision (young males) Confrontation of VF (dim/light) Pupil testing Motility Interpupilary distance
19
Q
Phoria vs tropia
A
Heterophoria = eye turn when covered Heterotropia = constant eye turn Orthophoria = no eye turn
20
Q
Heterotropia measurements
A
Frequency
Commitancy
Preference
21
Q
Unilateral cover test
A
Determines heterotropia or heterophoria
- Cover eye, examine uncovered eye motion
Repeat with near target
22
Q
Alternating cover test
A
Determines direction and magnitude of deviation
- Swap between eyes, examine eye that is being uncovered - Repeat with near target
23
Q
Phi phenomenon
A
Px notices motion of target during cover test
24
Q
Near point of convergence (NPC)
A
Distance from nose where diplopia occurs
Does not measure accommodation
Px says when target is blurred, then when it is double
25
Stereopsis
Measures steroacuity: smallest detectable depth
Polarized glasses: vectographs (local stereopsis)
Random dots: RD filters (global stereopsis)
26
Color vision deficiencies:
Protanope: missing red cone photopigment
Deuteranope: missing green cone photopigment
Tritanopia: missing blue cone pigment
Prot/Deuter/Trit-anomal: anomalous cone pigment
27
Ishihara test:
Protan/Deutan (red-green) defect presence test
Does not find severity, poor differentiation between protan and deutan
- 3s per plate
- Binocular initial screen
- Monocular if suspect
Requires VA>6/18
28
Amsler grid instructions
- 30cm, with reading glasses, orthogonal to sight
- Ask if black dot is present (if not AMD bad)
- Focus in Centre
- Notice any change in grid pattern
- Missing squares, black plots (Scotoma)
Warping (Metamorphopsia)
29
Confrontation VF
Facial amsler, hand comparison (any part looks different), finger counting, kinetic boundary (pen motion)
30
Finger counting extinction or neglect
Neglect: inability to see quadrant
Extinction: inability to see quadrant when several quadrants crowded
When neither present: R/L + FTFC
31
Swinging pupil test
Relative afferent pathway (RAPD)
- Light held 3s in eye
- Fast swap to alternate eye
Expect constriction, then dilation
32
Afferent pupil pathway
RGC layer forms afferent pupillary fibers, travel through optic tract to sup. Colliculus, then midbrain, then to Edinger-Westphal nuclei bilaterally (both sides).
Efferent fibers travel on oculomotor nerve to ciliary ganglion, then short ciliary nerves, to iris sphincter muscles for constriction
33
RAPD grading
1: weak constriction and great radiation
2: no motion, then great dilation
3: immediate dilation
4: immediate dilation, then constriction
5: dilation with no constriction after 6s
34
Direct, consensual, near pupil test
| Recording for full pupil test
Preformed after swinging to avoid bleaching
- Light in RE (note RE constriction/dilation)
- Remove
- Light in RE (note LE constriction/dilation)
- Px swaps focus to near target (note constriction)
Measure size/reaction/accommodation (PERRLA) and DCN
35
Motility process
Binocular motion between 9 gazes
| Report diplopia, pain, discomfort
36
Muscles and motility gazes, relative to Px right eye
Upper corner = R: SR, L: IO
Temporal: R: LR, L: MR
Lower corner = R: IR, L: SO
Opposite when in left eye regard
Upper: SR, IO
Lower: IR, SO
37
Contrast threshold and contrast sensitivity
Least difference between dark and light needed for resolution for a given spatial frequency
Contrast sensitivity: reciprocal of contrast threshold: high sensitivity = low contrast threshold
In units of luminance
38
Spatial frequency:
cycles per degree of arc subtended at eye
39
Spatial contrast sensitivity function
Contrast sensitivity (1/threshold contrast) over spatial frequency (cycles per degree)
Sensitivity peaks at 6 c/deg with sensitivity of 130 (0.007%)
Cuts off at 60 c/deg
Sensitivity 1 = 1 100% contrast
Sensitivity 100 = 100 1% contrast
40
Spatial contrast sensitivity function in photopic/mesopic/scotopic conditions
Photopic: normal
Mesopic (Dusk Rod transition): same starting point and peak time, lower peak and early cut-off
Scotopic: lower start/peak and early cut-off
41
Refractive error/AMD, cataract, Multiple sclerosis on spatial contrast sensitivity function
Refractive error/AMD = same starting point, similar peak, early cut-off
Cataract: low start/peak, and early cut-off
MS: Low start/peak, same cut-off
42
Pelli-Robson contrast sensitivity assessment
6/30 letter chart in triplets of decreasing contrast.
60 cd/m2 luminance, mono and bino
Each correct letter = 0.05 log CS units, first triplet = 0 Log CS
Continue until single letter cannot be read on 2 tries
Determines contrast sensitivity, no information on VA
43
HC/LCVA Verbaken contrast sensitivity chart:
High contrast and low contrast LogMAR VA chart
Measure VA on both charts, >3 line difference indicates abnormality
Determines spatial frequency, little information on contrast sensitivity
44
Vector vision contrast sensitivity assessment
Rows of 2 circles, one circle in a column has gratings
Px is asked to find which circle has gratings
Each row shows different spatial frequency
Determines spatial and contrast sensitivity
45
Takagi contrast glare tester assessment
Basically VF machine for contrast
46
Conditions where contrast sensitivity test is indicated
Cataracts, AMD, Diabetes, Parkinsons, Alzheimers, Optic neuritis, Multiple sclerosis, visual pathway lesions, High myopia
47
Astigmatism in relation to BVS
2 focal points along 2 principle meridians at different distances
Area between focal points is the interval of strum
Circle of least confusion: middle area of interval of strum
BVS places COLC on the retina
48
Types of astigmatism based on axis:
WTR 180 +- 30 degrees
ATR 90 +- 30 degrees
Oblique 45+-15, or 135+-15 degrees
Irregular: meridians are not perpendicular (keratoconus)
49
Types of astigmatism based on power
Simple hyperopic: Meridian behind retina and one on retina
Simple myopic: Meridian in front of retina and one on retina
Compound hyperopic: both meridians behind retina
Compound myopic: both meridians in front of retina
Mixed astigmatism: one meridian behind, and one meridian in front of retina
50
Duochrome concept:
```
Red 620nm and green 530nm
Shorter wavelength is refracted more
~0.5D difference
Hyperope sees green clear, vise versa for myope
Emmetrope sees yellow as clear
```
51
When is binocular balance not useful
Absolute presbyope
Strabismus
Monovision
Amblyope (brain favors one eye)
52
Clinical manifestation for poor binocular balance:
Vague discomfort (strain, headache)
Poor steroacuity
Unequal VA
53
Principle techniques for binocular balance in order of increasing sensitivity
```
Alternate occlusion
Vertical prism dissociation
Blurring
Septum
Polaroid
```
54
Binocular balance techniques
```
Alternate occlusion with fog
True septum
Modified Humphriss (phycological septum)
Polarizing filters
Prism dissociation balance
Red / Green duochrome
```
55
Reason for blurring eyes in binocular balance
Lowering central vision breaks ocular dominance.
56
Alternate occlusion steps
```
+0.75 in both eyes
Px focuses on 6/9 line
Alternately occlude R/L eyes
Add +0.25 to eye with best vision until reversal
Remove +0.75
```
57
Alternate occlusion advantages and disadvantages
Advantage: fast, easy to set up, can use trial frame
Disadvantage: constant breaking of fusion results in poor equilibrium, relies on Px memory (dementia), requires equal VA, not very sensitive
58
Prism dissociation balance steps
```
+0.75 in both eyes
Px on 6/9 line
+6.00 BU prism in right eye
Add +0.25 to eye with best vision until reversal
Remove +0.75
```
59
Prism dissociation advantages and disadvantages
Advantage: not reliant on memory, phoropter is fast
Disadvantage: requires equal VA
60
Polarizing filter binocular balance steps
+0.75 in both eyes
Polarized chart with 3 letter lines and polarized lenses placed
Each letter line is for one eye or both eyes
Add +0.25 to eye with best vision until reversal
Remove +0.75
61
Modified humphriss steps
+0.75 in LE
Monocular check of RE (+/-0.25) until best vision
Repeat with RE blur (+0.75)
Ensure blur is placed in RE before it is removed in LE when switching to maintain broken ocular dominance
62
Polarizing advantages and disadvantages
Advantage: constant fusion, does not rely on memory, most sensitive
Disadvantage: requires set up (phoropter lenses and screen polarizing filter), requires equal VA (unless chart has several VA lines)
63
Modified humphriss concept
Blurring contralateral eye creates central suppression with peripheral fusion, allowing binocular viewing.
Creates psychological septum
64
Modified humphriss advantage and disadvantage
Advantage: psychological septum is very sensitive, equal VA is not required, easy to use (trial frame), constant fusion, fast
Disadvantage: requires many lens changes,
65
Duochrome with prism steps
```
3 BUR and 3 BDL prism added
Px focus on line above threshold
Looking at top chart, which side is clearer
Red = add -0.25, vise versa for green
Switch to lower chart for LE
```
66
Duochrome with prism advantages and disadvantages
Advantage: not reliant on memory, saves time in lens changing
Disadvantage: confusing for Px (both prism and Duochrome)
67
Binocular spherical end point:
Offer +0.25
If better or same, add it
Stop if worse
Expect better OU VA
68
Cyclopegic refraction
Refraction "wet ret" following accomodative paralysis via cyclopentolate 0.5-2%, or tropicamide 0.5-1%, or atropine 0.5-2%
69
Atropine vs cyclopentolate vs tropicamide
| Peak and recovery time for mydrasis and cyclopegia
Atropine: pupil dilation peak (30mins) recovery (7 days), ciliary paralysis peak (60mins) recovery (7 days)
Cyclopentate: pupil dilation peak (30mins) recovery (1 day), ciliary paralysis peak (45mins) recovery (1 day)
Tropicamide: pupil dilation peak (20mins) recovery (4 hours), ciliary paralysis peak (30mins) recovery (4 hours)
70
Atropine/cyclopentate/tropicamide comparison
Cyclopentolate is most common for ciliary paralysis
Tropicamide is poor for ciliary paralysis
Atropine is too strong in ciliary paralysis
71
Phenylephrine drops
Sympathetic agonist to dilator muscle, rather than the parasympathetic inhibitor of other drops
Will not affect ciliary muscle for cyclopegia
72
Cycloplegic refraction procedure
```
Check risk of angle closure
Gain consent
Educate on adverse effects
Administer agent
Px waits 20-30 mins
Preform ret and subjective refraction
Dilated BVCE may be reduced due to increased aberration of larger pupil
```
73
Fluorescein:
Stains albumen in tear film
Examines breaks in epithelium via tear pooling
Good for contact and TBUT exam
Requires cobalt blue filter
74
Rose bengal/lissamine green
Lightly damaged epithelial cells are killed by dye as it stains nuclei
Marker for disease and cell death (herpes/DED)
75
Slit lamp: set up rules
Explain purpose of test, GAIN CONSENT
Focus slit lamp on rod
Clean slit lamp and hands
Instruct head placement and eye focus on wall behind
76
Slit lamp: diffuse what to examine
```
Superior lids/lashes/palpebral conjunctiva
Inferior lids/lashes/palpebral conjunctiva
Superior bulbar conjunctiva
Inferior bulbar conjunctiva
Temporal conjunctiva
Nasal conjunctiva
Inferior nasal punctum and caruncle
Iris
```
77
Slit lamp: optic section what to assess
Cornea layers
Lens layers
Van Herrick's
78
Slit lamp: diffuse order of exam
```
Low mag X6, light 45 degrees temporal
Sup. lids, Px looks down
Sup. Conj, hold lid up
Inf. Lids, Px looks up
Inf. Lid/conj, hold lid down in 3 spaces while scanning
```
79
Slit lamp: parallelepiped: order of exam
Medium mag >16X, light 45 degrees, low light intensity, 2mm beam
Assess tear film
Scan cornea
Verbalize motion while moving slit lamp
Move light nasally once at midpoint of cornea
80
Slit lamp optic section: order of exam
Max light intensity, minimum beam thickness, 25 mag, 45 degrees for cornea / 15 degrees for lens / 60 degrees for van Herrick's
Assess central cornea, focused STATIONARY view of layers
Push in from cornea through anterior chamber
Assess lens layers, each layer noted as presented
Assess van Herrick's on both sides, expect 0.5 of the corneal beam
81
Advantage and disadvantage of direct opthalmoscopy as diagnostic tool
Advantage: high magnification, image is upright
Disadvantage: no stereopsis (depth), only to equator, small FOV
82
Advantage and disadvantage of direct opthalmoscopy
Advantages: portable, use in immobile Px
Disadvantages: close proximity to Px
83
Advantage and disadvantage of indirect opthalmoscopy:
Advantage: larger FOV, medium magnification, upright image, can pass beyond equator
Disadvantage: no stereopsis
84
Advantage and disadvantage of BIO
Advantage: variable FOV and magnification, View to ora serrate
Disadvantages: image is reversed and inverted
85
Direct opthalmoscopy set up:
Dim light
Advise Px of close proximity, focusing on wall
+10D selected, reduce +ve as move closer (move focal point to retina)
Scan ONH->sup. Arcade -> Inf. Arcade -> nasal periphery -> macula
86
Fundus photography:
Stereo: lateral displacement of 2 images, depth provided via stereoviewers
Red-free (Black and white): filters 530-570nm
NIR/IR/Green-free (black and white): 624-640nm
Fluorescein angiography: several images after fluroescien injection
Ultra-wide: red/green wide image
Fundus autofluorescence: flurophore detection
87
Red-free photography purpose:
Accentuates vessels/hemorrhages
Less choroidal/retinal detail
Presents ONH, RNFL defects, venous pulsation
88
NIR/IR/Green-free photography purpose:
Accentuates choroid, retinal pigment
Less vessels
Presents pigment disturbance, choroidal rupture, naevi, melanoma
89
Fluorescein angiography
```
Injection of fluorescein into systemic blood, fundus image with cobalt blue, taken after 10s and several more every 2s after
1st image: choroid
2nd: arterial
3rd: arterial-venous
4th: venous
5th: choroidal
```
90
Ultrawide field photography:
"Optos" 82% image of fundus
Only red (choroidal structures) and green (retinal vessels) beams (red/green image)
High distortions
91
Optos advantages and disadvantages:
Advantages: wide FOV, fast
Disadvantages: vertical FOV limited by lids, poor contrast; small pathology missed (oedema/exudate/neovascularisation), peripheral distortion
92
Visual field assessment methods:
Gross perimetry: confrontation; Finger count, kinetic boundary
Central visual function: Amsler, autoperimetry
Kinetic perimetry: replaced by SAP
Static automated perimetry (SAP): 24-2 threshold, mono/bino
Frequency doubling perimetry: your old VF machine
93
Amsler grid concept:
At 30cm, each 5mm square subtends 1 degree
Tests central 10 degrees of vision
Used for AMD, diabetes, CSR, HT, myopia, systemic medication
94
The hill of vision:
Optic sensitivity over degrees from macula
95
Kinetic perimetry:
Object of changing size/intensity passes through seeing area
Identifies area of equal sensitivity
Shows scotoma and blind spot
96
Static automated perimetry:
• Our VF machine
Provides automated, efficient, fast analysis
Requires less than 20% fixation loss
Monitors false positives/negatives
97
Cortical filling:
Loss in VF is guessed by surrounding retinal neurons
| Makes slow loss in VF hard to notice
98
Threshold tests for SAP:
30-2: 30 degrees from fixation
24-2: 24 degrees from fixation, nasally moves to 30 degrees
10-2: 10 degrees from fixation, many points 2 degree seperation
99
SITA
Swedish interactive threshold algorithm:
Standard, Fast, Faster
Alternately full threshold may be used, but takes longer
100
Reliability indices of SAP:
Fixation loss <20%
False positives <15%
False negatives <20%
Gaze tracking: upticks (loss of fixation); downticks (blinks)
101
dB as a measurement of VF sensitivity:
dB = 10 log(Luminance max/luminance)
| Higher dB = higher sensitivity at point in VF
102
Total deviation plot of VF
Numerical plot, absolute dB at each point against mean for age group
Overall decrease in dB is noted in cataracts, reducing VF defect detection
103
Pattern deviation plot
Numerical plot, generalized depression or elevation of VF by age and disease
Reveals patterns / localization of defect
Works with cataracts , allowing defect detection
104
Probability plot of VF
Grey scale for probability of occurrence of deviation in normal population
105
Total deviation (mean deviation) vs pattern SD defect plots in VF
Total deviation: each point is age matched, reflects overall depression from cataracts
Pattern deviation: each point is corrected for global change vs age change; reflects focal depressions even while cataracts is present
106
Glaucoma hemifield test (GHT):
Checks 5 glaucoma sensitive regions superiorly to the inferior region
Will show glaucoma suspect (Borderline/Outside normal limits)
107
Location of lesion and visual field defect, in reference to RE optic tract (right side of brain):
Pre chiasm: full mono VF loss
Post chiasm: full RE / sup. Temporal LE loss
Mid chiasm: UE temporal loss
Post chiasm: UE Left loss
Outer optic radiations: "Pie in the sky" UE sup. Left segment loss
Inner optic radiations: "pie on the floor" UE Inf. Left segment loss
Visual cortex: UE Left loss with macula sparing
108
Factors affecting VF results
Test factors: spot size/duration, BG illumination
| Px factors: L/D adaptation, correct eye patch, correct trial lens (Age/prescription), education, cooperation
109
Frequency doubling perimetry:
Old VF machine
Detects magnocellular GC dysfunction
Sensitive to glaucoma, poor prediction of severity
110
Contradictions for dilated fundus examination (BIO)
Drop allergies, pregnancy, AC-IOL/Iris clips, miotic glaucoma therapy, penetrating injury
111
Direct opthalmoscopy advantages and disadvantages
Advantage: Image is upright, high magnification (15x)
Disadvantage: Image is virtual, no stereopsis, low FOV, only to equator
112
Monocular indirect opthalmoscopy (MIO) advantages and disadvantages
Advantages: Upright image, can see past equator, no dilation
Disadvantages: No stereopsis, low magnification
113
Fundus lens (slit lamp) advantages and disadvantages:
Advantages: stereopsis, variable FOV / Magnification, view to ora serrata
Disadvantages: image reversed and inverted, slit lamp required,
114
BIO advantages and disadvantages:
Advantages: Stereopsis, high FOV, View to ora serrata, portable, good view through opacities
Disadvantages: low magnification, needs dilation, image reversed and inverted, requires drops
115
How lens power affects FOV and mag in fundoscopy
Higher power = Lower mag, higher FOV
| Vise versa for lower power
116
Foveal reflex
During Fundus lens, the slit will how a bright shine in fovea due to the dipping and subsequent light reflection
Without this sign macula oedema is suspect
117
Px gaze in relation to what area of retina is being observed with slit lamp AND BIO
Px looks up: Sup. Retina in view
| Px looks down: Inf retina in view
118
Lens tilt with slit lamp
Tilt lens with Px gaze
| Eg. Inf. Edge tilt inward with up gaze
119
What to document in fundoscopy
ONH: NRR color/thickness/CD ratio/ PPA, SVP, LC
RNFL: BDB
Viterous: floaters, clarity
Macula: flat/reflex/drusen/pigment change
Periphery: Lesions/haem
120
ONH documentation:
CDR
NRR: ISNT, pink, healthy, disc margin distinct
-ve SVP
-ve LC
121
Indications during case history for BIO examination
PC: reduced VA, photopsia, floaters, Metamorphopsia, scotoma/VF deficit, diplopia, ptosis
GH: diabetes, HT, cholesterol
POH: retinal disease/lesion, review of past retinal lesion, High myopia (>-6D), cataracts
122
Recording position and size of lesion on retina
As # of disc diameters in a given direction (temporal) from ON
And as # disc diameters in size
Also record time and drops used
