Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

CP1 mid sessionals term 1 > Important content to remember > Flashcards

Important content to remember Flashcards

(70 cards)

Start Studying
1
Q

describe the optic disc, cup and macula and fovea.

describe arteries vs veins
and isnt rule

A

optic disc is nasal and the macula is temporal.
optic disc is the blind sppot. no photoreceptors.
pinky orange colour but not good if white.

arteries are thinner and lighter and veins are thicker and redder.

I>S>N>T follows isnt and if isnt then isnt glaucoma.
neuroretinal rim is the broadest in inferior and thinnest in temporal.

cup size= 0.3-0.4mm. can be different. normal in some people or indicator of damage.

macula= posterior retina that contains pigments and photoreceptors cells. responsible for colour and central vision. fovea is the depression of central inner macula=clearest vision.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

when examining the eye what do you look for (10)

A

overall view of the eye
assess quality of fundus
assess disc appearence
colour (pink)
clarity disc margin (sharp edges)
cup to disc ratio
neuroretinal rim isnt rule
assess arteries and veins

repeat for each 4 quadrants
assess macula and fovea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

high blood pressure vs high intraocular pressure

A

high blood pressure= can see it in the back of the eye.=hypertension screening.

high intraocular pressure= due to poor drainage of aqueous humour.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

monocular

describe and
mag and fov numbers

A

using one eye to assess
views real and erect images
condensing lens required
greater fov and wd
lower mag
no stereopsis (3d)

mon indirect- 5 times mag
15 degrees fov
independent of patients Rx
no stereoscopic view

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

binocular

A

using both eyes to assess
stereoscopic, aerial
condensing lens
real inverted laterally reversed
greater fov than direct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

direct vs indirect

A

direct- small fov, high mag, close wd, dim image, monocular, easy to use, mag image, erect image

indirect- high fov, low mag, far wd, need to dilate pupil, stereoscopic, inverted imag.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

keeler wide angle vs Pan optic

A

monocular
10 times larger fov than direct

Pam optic- 5 times larger than direct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

binocular

A

using both eyes to assess
stereoscopic, aerial
condensing lens
real inverted laterally reversed
greater fov than direct

higher power condensing lens= decreases mag= increases fov

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

indirect biomicroscopy( slit lamp) and compare to head mounted bio
and when to use

A

fov depends on lens power and diameter of lens
90 and 78D bi convex
60D and superfield unidirectional

less mag w stronger lenses.

lens used with slit lamp
short wd
gerater mag than head mounted bio
smaller fov than head mounted bio

when to use-
poor direct view
stereoscopic view
wider fov than direct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

binocular indirect
head mounted bio

prinicples
properties
procedure
and when to use

A

principles-

stereoscopic view
hand held condensing lens
image inverted and laterally reversed
real image

condensing lens most common is +20
flatter side towards patients
lower powers have higher mag, smaller field of view, greater wd.

properties-
2.5 times mag
30 degrees fov
must dilate

procedure-
set up headbang
eye piece rx and pupil size
hold condensing lens in front of eye
pull lens back until fundus image fills lens
8 positions
remember inversions

when to use- poor direct view
stereoscopiv view
to see whole fundus
to assess for diabetes, rd symptoms or young children

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

digital fundus camera

A

large stand instruments
2 light sources- 1 to take flash photo and 1 to view fundus

optical design based on indirect opth
specialised low power microscope w an attached camera

immediate viewing
archive and monitor
images can be shown to patients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

oct

A

most common used for routine imaging of retina and optic nerve in high resolution

non invasive cross sectional imaging of retina by measuring the backscatter and delay as it journeys through the ocular tissue comparign it to a known reference path

provides thickness data of retinal layers
used in med retina care, glaucoma care, primary health care and screening

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

equation for direct opthalmoscopy

A

M= Fe/4 times 1/1-wK

Fe= power of eye +60
w= working distance (negative and m)
k=ocular refraction

mag= Fe/4 therefore emmetropes its always times 15, if myope then power is higher than 60 then it will be more than 15
for hyperopes power is less so it will be less than 15

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

higher refraction of the patients eye is it easier or difficult to assess back of eye and why

A

more difficult it is to assess the back of the eye

as increased refraction= increased mag= decreases fov

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

if light doesnt focus on the retina but behind it

A

blur circle is formed on the retina
we can work out the size of this= field of view

j(m)=g(k-w)/Fe

j= blur circle of fov
g= pupil size (m)
k= ocular refraction
w= reciprocal of wd (m and negative)
Fe= dioptric power= 60D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

factors affecting fov and mag

A

pupil size increases increases fov
sighthole size
wd closer increases fov
subjects ametropia. increasing decreases fov

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

good ophthalmoscope

A

clear uniform light patch
fov coincident w light patch
minimise corneal reflections
abscence of sighthole flare
range of target apertures
extra targets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

for j= k-w equation

A

convert w to metres first and then make sure its negative
and then work out the reciprocal

and then do the equation

and then times by 1000 at the end!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Human eye refracts w 2 ocular structures

A

cornea = 2/3 refraction 40D
lens= 1/3 refraction 20D
overall= 60D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

3 elements to focus light

A

shape of cornea,
power of lens
and length of eyeball

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

far point and near point

A

furthest distance a person can see without glasses or contact lenses. can be at infinity, behind or in front of an eye.

near point= closest point at which a person can see an object in perfect focus without glasses or cl

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

focal point

A

where parallel light meets after passing through the lens.
can be at the macula in front of the macula or behind the macula or retina.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

myopia

A

focal point is in front of the retina
far point is in front of the retina
blur circle is formed on the retina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

myopia and why

A

focal point is in front of the retina
far point is in front of the retina
blur circle is formed on the retina

if cornea is too curved or if the lens is too powerful (refractive ametropia)
or bc eye is too long or combination of these (axial ametropia)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
hyperopia
focal point is behind the retina, far point is behind eye and image formed behind retina. blur circle on retina. corrected with positive lens.accom can fix this if young could be bc cornea is too flat or if lens is too weak (refactive ametropia) or bc eye is too short or combination (axial ametropia)
26
astigmatism
usually occurs with myopia or hyperopia irregular curvature of cornea or lens. light rays focus in different locations. theres 2 focal points 1st and second. use cylindrical lens to correct this light can hit at one meridian and other.
27
2 types of astigmatism
against the rule (cornea more curved in horizontal meridian) with the rule (cornea more curved in vertical meridian))
28
correction
amount of power in D needed to bring rays of light back onto focus on the retina if + hyperopia if - myopia
29
visual acuity
sharpness of vision measured by the ability to discern letters or numbers at a given distance according to a fixed standard. distance= 6m for far near= 40cm
30
visual acuity
sharpness of vision measured by the ability to discern letters or numbers at a given distance according to a fixed standard. distance= 6m for far near= 40cm snellen chart= widely used problem= scale is not linear, crowded, hard notation
31
minimum angle of resolution
reciprocal of snellen fraction logMAR= log 10 of the minimum angle of resolution (MAR) bailey lovie charts. same no of test letters but easier to use
32
how does the log mar thing work
each letter read correctly= -0.02 logmar logmar- (0.2 times no of letters read)
33
picture snellen
lea symbol chart- based on logmar principles and uses shapes unaided vision- check va with glasses and test worst eye first n-notation- N= height of letter. 1/72 of an inch. N5= 5/72 inches/ etc jaeger and m notation if you cant recognise letters- orientation of rotated snellen c tumbling E orientation of prongs key card point matching picture or symbol charts teller nad keller acuity cards cardiff acuity cards logmar acuity cards
34
vision in spherical ametropia and lens lens and ciliary muscles and accom at near
Rx can affect va accom and pupil size also afects va lens- shape isnt fixed. its responsible for accomodation= eye changes its power by the lens changing its shape. ciliary muscles are relaxed= lens zonules taut, lens flattened. ciliary muscles contracted= lens zonules relax and lens surface becomes fat= power=accom distant-cm relaxes near- cm contracts lens fat= accom
35
vision in spherical ametropia and lens lens and ciliary muscles and accom at near
Rx can affect va accom and pupil size also afects va lens- shape isnt fixed. its responsible for accomodation= eye changes its power by the lens changing its shape. ciliary muscles are relaxed= lens zonules taut, lens flattened. ciliary muscles contracted= lens zonules relax and lens surface becomes fat= power=accom distant-cm relaxes near- cm contracts lens fat= accom (as age increases lens flexibility decreases and hence power decreases=presbyopia)
36
near vision triad
convergence- inward movement of eyes towards each other pupil miosis- constriction as accom acccomodation= increases lens power
37
emmetropia, hyper and myopia accomodation
not using accom for distant near= closer distance= increases power of eye accom= ray has to bend through a larger angle to focus them onto the retina. hyperopia- can accom to bring it forward near= accom all the time myopia= cant as it brings it more forward
38
length of standard eye
22.22mm longer then myopia if shorter than hyperopia
39
power
+60D if higher than myopia if lower than myopia
40
ametropia what it does to pupil size and blur circle with va.
decreases pupil size decreases blur circle and increases vision. large pupil= blur circles overalp and cant be resolved. so we can use pinhole aperture to decreases pupil size of the retinal blur circle to get the best acuity. if vision does not improve w pinhole then vision loss is due to non refractive causes eg disease.
41
decimal notation
snellen numbers divided
42
Astigmatic ametropia if
The eye displays 2 different refractive powers in 2 planes when meridians are perpendicular to each other. 2 focal points instead of 1. Cone or rugby ball shape. Steeper meridian more curved= light is refracted more by this curvature and least by the flattest curvature. (Ocular astigmatism)
43
Spherical ametropia
Same curvature over the entire surface Light is refracted by the same amount when it passes= -> one sharp focus
44
Corneal, lenticular and ocular astigmatism, with and against and oblique
Corneal astigmatism- major source of astigmatism. Measured w keratometer. Lenticular- astigmatism by anterior and posterior surfaces of lens being tilted. Calculated by taking corneal readings away from the total astigmatism. Corneal and lenticular total astigmatism. Ocular astigmatism- regular if meridians are 90 degrees apart Irregular- meridians any angle apart not perpendicular Ocular can be with the rule or against. With- more curved in vertical and against is more curved in horizontal. Oblique- one meridian lies between 120 and 80 and other between 30-60
45
What is the circle of least confusion
Dioptric midpoint between the anterior and posterior focal point. We need to move this onto the retina This is the sphere power+ (cyl power/2)
46
Classification of astigmatism (regular)
Simple hyperopic astig - focal line 1 on retina and one behind. Plano and positive Compound hyperopic- focal line 1 and 2 behind retina. Both positive. Simple myopic astigmatism-focal line 1 on retina and one in front. Plano and negative. Compound myopic- focal line 1 and 2 are in front of the retina. Both negative. Mixed astigmatism- focal line 1 in front of retina and one behind retina, pos and neg. Larger difference- larger distance between 1st and 2nd focal line.
47
Vision in uncorrected astigmatism and what is it affected by
Accommodation isn’t too useful as 2 focal points Stretched or distorted Affected by: amount of astigmatism, types of astigmatism, axis direction
48
Optimum vision
When circle of least confusion on retina. Can happen in simple or compound hyperopia if enough accommodation. Otherwise need to fix Oblique is likely to affect vision more.
49
How to correct astig
1st= put 2nd focal line on the retina by adding + or - lenses 2nd= then add - cylinders to push the 1st focal line left to the retina +lenses= pushes it left - lenses= pushes it right If you add + lenses it pushes both focal lines left. And then you need to push it right using negative lenses. If you add - lenses moves it right then you put second focal line onto as well so add - again
50
Indirect vs direct mag and fov
Indirect- typical M= times 2- times 5 Typical fov= 25-45 degrees Direct- Typical M= times 15 Typical fov= 10 degrees
51
What affects indirect
Pupil size effecting diameter Condensing lens power Distance from patient to lens Distance lens to observer Ametropia
52
retinoscopy used to to what
Objective Used to measure patients Rx Useful and accurate Screen for ocular disease: keratoconus, media opacities Specialist retiniscope- next year, accommodative stability, accommodative lag Dynamic ret- next year Wd= 67cm Can put in drops to relax accommodation
53
Describe the retinoscope
Eyepiece- light source - spot/streak bulb. Collar- needs to be kept down= divergent light rays The ret reflex is normally red or orange. Trial lenses are addd till reversal. Estimate Rx. Remove working distance. 1/0.67= 1.50 so minus 1.50
54
Where is the ret reflex
Appears to be located in the patients pupil but it’s anywhere front or behind. If accommodation is relaxed external image is formed at the far point of the eye.
55
Vergence of light rays
Dependent on patients Rx Emmetrope= rays leave parallel far point at infinity Myope- rays leave convergent far point In front of eye Hyperope- rays leave divergent far point is virtual. Only converging light focuses on the retina.
56
Far point explaining the patient and examiner eye thing
If far point is behind patient= hyperope with If between patient and examiner- myope and against If behind examine low myope= with Far point should be coincidental w examiners ret. neutral- no movement. Bright. Fast.
57
If with and against and over correction snd neutral
Add positive lenses till neutral Against= add negative lenses till neutral Overcorrection= against Neutral lean forward with lean back= against to check.
58
How to do ret
Accom relaxed= distance Dim room illumination Px observes target at 6m Wd=2/3m Both eyes open Use ret in right hand when examining left eye Keep the same wd Adding lenses moves the far point to the examiners ret. Fog the other eye = against Neutral= fast, bright, no movement;
59
If -1D what does that tell us
1/ far point So here far point is 1m in Front of patients eye
60
No movement
Wouldn’t add anything bc neutral Far point is at the retina
61
If neutral does this mean the person is an emmetrope
No, it means the far point is at the examiners ret This doesn’t mean the person is an emmetrope. Emmetrope= far point at infinity so you still need to bring this to the retinoscope to check the eye. And you add positive lenses to do this.
62
2 ways to vary the working distance
Add lenses to vary the far point plane Vary wd, only do this if at neutral
63
If power is pos or Neg
You know if it’s in front or behind
64
How to correct w spherical sylindrical lenses
Correct slowest with first or fastest against
65
Variations in ret and cycloplegia and methods of ret
Can use trial frames, ret bar, or phoropter. Cycloplegia- relaxed accommodation by relaxing ciliary muscles. Pupils get dilated. Ensures we know patients real Rx Methods of ret- streak, Spot or static ( patient fixated on a distant target w accom relaxed)
66
Near fixation or Barrett’s method
Used when examiner is unable to do ret accurately with both eyes eg lazy eyes Only one of practitioners eye is used Perform ret on both eyes of Px whilst patient fixates the ret and then check spherical component Ret at near- and ret at distance. Do near one for both eyes and then distant one for the eye that is good for examiner. Them work out difference and the And apply this difference in both eyes.
67
Mohindra
Useful in children that cannot fixate distant targets Dark room Fixates ret light Wd=50cm monocular Correc of -1.25D
68
How to do ret in opacities, large pupil and keratoconus
Opacities- if in centre can’t really do it but dilate pupil or move closer Large pupil- focus at the centre Keratoconus- cone shape, Sllit or scissor reflex, use lens step larger than 0.25D and use bracketing technique. Increase room illumination to decrease pupil size
69
Factors affecting accuracy of ret
Intra-individual variation (same people) Inter individual variation (between diff people) Not concentrating on movement in centre of pupil Age of px Off axis errors Wd errors Blocking pxs errors of chart-> likely stimulating accom
70
Speed of reflex
Important in estimating neutral point Dioptric power= reciprocal of distances

CP1 mid sessionals term 1 (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions