Objective retinoscopy

Clinical pearls while performing
Objective Refraction :
What we should not miss?
Moderator: Presenter:
Hira Nath Dahal Bipin Koirala
MMC , IOM
Final year

Presentation Layout:
Basic outline of Retinoscopy
Retinoscopy in different refractive errors
Special consideration for children's
Common errors in retinoscopy

Introduction:
Procedure in which examiner determines the refractive state of
eye on the basis of optical principles of the refraction without the
need of subjective response on the part of the patients :
Objective refraction
Common methods of objective refraction are:
Retinoscopy
Keratometry
Auto Refraction

Retinoscopy:
A method of objective refraction in which refractive state of eye is
determined with the help of retinoscope:
Retinoscopy is of two types :
1. Static retinoscopy
2. Dynamic retinoscopy

Materials and Tools needed during
Retinoscopy
1. Retinoscope ( Spot or Streak
retinoscope )
2. Distance vision chart
3. Near vision chart
4. Loose lens trial set / lens bar
5. Adequate Illumination ( Room
illumination & Vision chart
illumination)

 Aim: Neutralize the movement observed on retinoscopy to achieve
reversal (no movement)
 Occurs when the far point of the eye being examined coincides with
the nodal point of the practitioner’s eye.

A point in space conjugate with fovea when accommodation
is relaxed is called far point.
Location of Far points in different Refractive Errors
1. Myopia : Between examiner and patient
2. Hyperopia : Behind the eye
3. Astigmatism : Has two far points one for each meridians
4. Emmetropes : Has far point at infinity
Far point ????

In Myopia Minus lens diverges rays on to the retina and
conjugate fovea with infinity
In Hyperopia Plus lens converges rays on to retina and
conjugate fovea with infinity
In Astigmatism cylindrical lens will make the fovea
conjugate with infinity.

Instrumentation of a Retinoscope

Projectingsystem
Main purpose:
To illuminates the retina
Consists of:
 Light source
 Condensing lens
 Mirror
 Focusing sleeve
 Current source

Projecting systemof Copeland type.

Projectingsystemof WelchAllyn
.
. . . .
.

Clinical pearls
Concave Mirror vs Plano Mirror Effect
Concave mirror effect Plano mirror effect
 Less commonly used technique  Commonly used technique
 Effective source of light is placed in
front of mirror
 Effective source of light is placed behind
the reflecting mirror
 Convergent light beam is emitted  Parallel or diverging rays are emitted
 With motion : myopia  With motion : hyperopia
 Against motion: hyperopia  Against motion: myopia
 Used to conform neutrality  Generally Plano mirror effect is used
 Used in media opacity as it increases
light intensity

StreakRetinoscope vsSpotRetinoscope
Clinical pearl

Luminous Retina
We will illuminate the fundus with the retinoscope and observe rays
coming from the retina
When the light rays leaves the retina, the optical system of the eye will
also applies vergence to the rays.
If we illuminate the retina with parallel rays (plane mirror), the
reflected rays leave the eye according to the refractive error.
 Emmetropia, rays leave parallel.
 Hyperopia, rays leave diverging.
 Myopia, rays leave converging.

Looking through the peephole in your retinoscope, you will see the
emerging rays as a red reflex in the patient’s pupil.
If you sweep the streak across the eye, the reflex you see will also
move.
If the emerging rays have not converged to a point (the FP), the retinal
reflex will move in the same direction as you move the streak; this is
called the with motion reflex (WITH).
If the rays have come to the FP and diverged, the reflex will move
opposite to your movements; this is the against motion reflex
(AGAINST)

Before commencing retinoscopy a variety of factors need to be
considered to ensure the results obtained are accurate and reliable.
These includes:
1. Working distance,
2. Lighting conditions,
3. Fixation target
4. Patient and Examiner positioning

Working distance
The distance from the retinoscope to the patient’s eye is known as the
working distance
Performing retinoscopy at an infinite distance from the patient ie
greater than 6m away, means no allowance needs to be taken for
working distance.
However, it is not practical to do this; the reflex will be dim, difficult to
observe, and it will be impractical to change the correcting lenses.

As a result, practitioners perform retinoscopy at a distance less than
infinity, but modify their final retinoscopy result to take account of their
‘working distance’.

Most practitioners use a working distance of 50cm , which requires
adding a working distance lens of -2.00Dsph to the final result.
Alternatively, a working distance allowance lens of +2.00 Dsph can
be placed in the trial fame prior to commencing retinoscopy.
Clinical pearls
How to calculate working distance allowance lens ?
P= (1/D) diopter
P= working lens power
D= working distance in cm
EXAMPLE for 50cm working distance ide +2.00D

Whyworking lens to compensatefor the
workingdistance?
Advantages-
 Instant identification of myope orhyperope.
 Working lens might help relaxaccommodation.
 No need for mental arithmetic to allow for working
distance
Disadvantages-
 Too much blur does not necessarily relax
accommodation.
 Working lens adds extra reflections to the view.

Lighting condition
It is ideal to perform retinoscopy in a darkened room.
This will cause the pupil to dilate, making the reflex more visible also to
reduce distractions and provide contrast for the reflex.
However, as a result of dilation aberrations and accommodation may be
increased.
The retinoscope light levels should be kept on medium.
If too bright, the pupil may constrict, so inhibiting visibility.

Fixation target
Fixation target : Variable depending on the type of
retinoscopy being performed .
Targets can be :
1. Accommodative
2. Non accommodative
3. Letter target
4. Interesting toys for childrens
5. light of retinoscope

In static retinoscopy : Patient fixates on a distance target.
Target should ensure that patient’s accommodation is relaxed,
otherwise the final prescription will be incorrect.
With the advent of computerized test charts, practitioners have a
plethora of targets to choose
Clinical pearl:
But the green section of the duochrome is considered to be a good
fixation target as it induces the least amount of accommodation.

Examiner positioning and instructions.
Patient must sitting comfortably, not standing as standing patients will
slightly alter the practitioner’s working distance.
Present a large and non-accommodative target at the furthest point in
the room.
Adjust the trial frame or Phoropter in front of the patient prior to
beginning.
Practitioner’s chair must also be adjusted in front of the patient to
ensure they are at eye level with the patient.
Use your right eye to examine right eye of patient and vice versa

 “Keep looking at the distant target”
 “Please tell me if my head gets in the way
and you cannot see the target anymore”
 “The target might be blurry- don’t worry
about that, but just relax and keep
looking in that direction”
 “Please keep both of your eyes open”
Patient instructions:

Starting point
While scoping eye with retinoscope you can see the fundal reflex in
the pupil
Light reflected from the fundus has two components:
1. A diffuse component, which is also called backscatter
2. Adirected component
And the nature of reflex motion will give you idea about
starting point
Also previous prescription can be used as an reference for
starting retinoscopy.

Movement
(WD:50cm)
With motion
Emmetrope
Hyperope
Myope
(<-2Dsph)
Against motion
Myope(>2Dsph)
No movement Myope =2DSph

Clinical pearls :
Always suspend the accommodation in contralateral eye(fixing eye)
either while examining if not negative result may be seen.
Assess the reflex of the right eye without lenses, first moving the
retinoscope streak around all meridians, looking for a break in reflex
indicating the presence of astigmatism.

1. If Astigmatism is present, line the streak up where the reflex is in line
with the streak angle.
a. Individual meridian must be neutralized separately
b. Once the first meridian is neutral, move the streak 90 degrees around
from the first meridian’s angle to neutralize the second meridian.
2. If the reflex appears to line up in all directions with equal width,
movement and speed, the refraction is Spherical.

Characteristics of a Retinoscopic Reflex
Reflex
Direction
Speed
Width
Brightness

Direction
a. No motion / Neutral
b. Against motion
c. With motion

Brightness
An experienced optometrist can use brightness as an important cue in
process of neutralizing the light reflex.
Brightness of reflex is related with the sharpness of focus of light into
the retina and the area of retina observed as filling the pupil of the eye.
Why reflex is dull in high errors?
When the patients retina is not conjugate with the peephole of the
retinoscope, the illuminated area of patients retina is usually greater
than observed area so reflex is largely out of focus spreads in the area
greater than the area of patients pupil and hence appears dull.

Clinical pearls
 Large errors have dull reflex,
 Small errors have a bright reflex
 Dimmer reflex
1. Smaller pupil (Hyperopic and elderly)
2. Darkly pigmented RPE
3. Media opacities

Width
 Width is related with the distance between far point and the
examiner eye
 When the distance between patient and far point increases the
reflex width will gradually narrowed
 And when the distance between them reduces the reflex will
gradually broaden and ultimately fill up the pupil when far point
and eye get conjugated.

Speed
 Speed always depends on amount of residual Ametropia during
retinoscopy
 On approaching neutrality speed will increase.
 Speed less than half – Ametropia more than 3.00DS from neutrality
 Speed 3 times – 0.50DS from neutrality
 Speed 6 times – 0.25DS from neutrality
 Speed infinity at neutrality, so pupil seems covered with reflex

Clinical pearls
 For with movements always go on increasing plus power greater than
working lens .
 For against movement go on reducing plus ( adding minus over working
lens )
 For fast movements change small power steps
 For slow motion change greater steps
 If reflex is dim , slow and difficult to interpret add high plus / minus
alternately to note improvement of visibility of reflex
 Also we can switch concave effect to raise the brightness and speed of
reflex for better judgement.

Reflex Observation Meaning
Brightness Dim Far from Rx
Bright Close to Rx
Streak size Narrow Far from Rx
Wide Close to Rx
Movement direction With Need more plus
Against Need more minus
Movement speed Slow Far from Rx
Fast Close to Rx
Summary Table

Procedure for Spherical Errors
Spherical
Error
With
AgainstWith
Against
No lens
+2 Dsph
Increase plus in
0.25 steps till
reversal
Reduce plus in
0.25 steps till
reversal
Increase minus
in 0.25 steps till
reversal

Procedure for Astigmatic Error:
In astigmatic error two principle meridian have different far point so
they must be neutralized separately.
All the procedure of changing lens is same as spherical error (mentioned
in previous slide)but each meridian must be considered separately.
Astigmatic error can be assumed by following 3 methods:
1. With two spherical lenses and optical cross
2. With one spherical and one cylindrical lens
3. With two cylinders

Clinical pearls for Astigmatism
To identify and confirm the axis as well as to locate exact principle
meridians in an astigmatic patients there are following 4 special
methods.
Intensity phenomenon
Thickness phenomenon
The Break & Skew phenomenon
Straddling the axis

Intensity phenomenon
The streak reflex appears brightest when the examiner are
streaking the meridian of the correct axis
Moving away from the correct axis, the streak reflex becomes
more dim
Intensity
Dim
Brightest

Thickness phenomenon
The streak reflex appears to be narrowest when we are streaking the
meridian of the correct axis
As we move away from the correct axis the streak reflex becomes wider

Break and skew phenomenon
Break in the alignment between the reflex in the pupil and the band
outside (intercept) it is observed when the streak is not parallel to
one of the principle meridian
If the streak is not aligned with the true axis oblique motion of
streak reflex will be observed on movement of the steak.

In higher amounts of astigmatism, the streak reflex will tend to stay
on-axis even if the streak is rotated off-axis
So break and skew phenomenon helps to locate correct principle
meridian

Clinical pearls
High power estimation :
High error often simulate following two conditions:
1. Hazy media
This appears as either no reflex, or a very dull one. Placing
weak plus and minus lenses without a change in the reflex seems
to confirm your suspicion of opaque media
2. Neutrality (This appears as a full, motionless reflex (pseudo
neutrality), suggesting that you are near the endpoint.
Simply lean in 10 to 15 cm (4 to 6 inches). If the reflex does not
change, you cannot be near NEUT so try the strong lens check just
described.

Estimation methods are very useful because
1. Easily conform the refractive error
2. No need of extensive trial set and lens.
3. Quickly perform the retinoscopy in uncooperative child.
Myopic estimation:
1. Against motion is seen(examiner is sitting beyond far point)
2. Examiner will gradually approach the patient from his working
distance till with reflex is noted
3. And the distance between the patient and point at which reversal
obtained is noted.

Example :
At WD: 50cm so (+2 Diopter)
If neutrality or reversal is noted at 25cm from patient then net
error will be -4 Diopter
Hence same neutrality will be obtained if -2.00 Diopter lens is
placed in front of patient eye

Hyperopic estimation:
We can estimate the amount of gross hyperopia (up to about 5 D)
by a technique called Enhancement.
On changing from plane to concave effect the narrowest retinal
reflex is called as Enhanced band.
By comparing width of enhanced band with intercept estimation is
made.
At 1 D WITH, lowering the sleeve will not enhance the retinal band
In higher amounts of WITH, you can enhance the retinal reflex.
As you slide the sleeve down a little more, the enhanced retinal
band of 2 D WITH appears well before the intercept is enhanced.

In +3 D, the reflex appears enhanced at a still lower sleeve height, nearer
the intercept.
The band of +4 D enhances just before the intercept.
At 5 D WITH, the retinal reflex and intercept are enhanced with the
sleeve at the same height.

Estimating the cylinder : Enhancement
technique
Once the spherical meridian is neutralized, the width of the astigmatic
reflex indicates the power of the cylinder.
As a rule, the thinner the reflex in the cylindrical meridian, the greater
the astigmatism.
If the streak is wide, you are nearer about neutralization, so of course
there is less astigmatism.

In low astigmatism, which you cannot enhance, the width of the pupil
reflex gives the best estimate of cylinder power.
In higher astigmatism, in which the intercept and reflex narrow
increasingly as you enhance larger cylinders, the intercept gives us the
most accurate indication of power.

Clinical pearl
How to conform neutrality?
At neutral point
1. Reducing plus lens power 0.25D (increasing minus by
0.25D) should result in the observation of “with”
motion
2. Increasing plus lens power to 0.25D (decreasing minus
by 0.25D) should result in the observation of “against”
motion

Clinical pearl
Always it is not possible to obtain end point as neutral point with pupil
fill with light glow so in many cases there is two possibilities .
• Neutralization of red reflex in all
meridian and no motion is appreciated
Neutral
• Real end point of retinoscopy
• Overcorrection by 0.25D should cause reversal of
the movement
• Slight forward movement should cause with
movement & by slight backward movement
against movement
Reversal

 Due to small pupils/cataract/other media opacities: faint
retinoscopic reflex
 The practitioner finds easy as moving closer to the patient
 Involves a WD as close as 20 cm/or even 10cm
 Eg: if possible at 20 cm WD then +5.00D is subtracted
from lens power
Clinical pearl
Radical Retinoscopy

Direct Retinoscopy???
1. In this technique, you hold the retinoscope close to the patient’s
eye (as with an ophthalmoscope) i.e 5cm
2. while looking for the image of the bulb filament focused on the
retina (retinoscopic focus)
3. In direct retinoscopy, we seek the sharpest, brightest image of the
filament focused on the retina
4. As in direct ophthalmoscopy, the image we see is affected by our
own refractive error and accommodation
5. The technique is especially helpful when the reflex is aberrated or
dull and in aphakia and other high ametropias.

Mohindra Retinoscopy
 Also known as near monocular retinoscopy
 Estimate the refractive status of the eye in childrens
 The stimulus or fixation is the dimmed light source of
the retinoscope in a darkened room
 The retinoscope is held at a distance of 50cm with
hand-held trial lenses
 Accommodation remains stable during this technique

What actually happens ??
Most patients exhibits anomalous myopia during retinoscopy
This excessive refractive power reflects a shift of accommodation
towards the patients intermediate resting focus under reduced
stimulation
To compensate for this effect, a tonus factor is applied to the
gross refraction obtained with near retinoscopy
Tonus factor is +0.75D

In addition , taking the WD in consideration ( if 50 cm)
i.e. -2.00 D
The total adjustment factor will be :
Working distance + tonus factor = ( -2.00 D + 0.75 D)
= - 1.25 D

Procedures
1. The room light is dimmed
2. The child is encouraged to fixate the retinoscope light
3. Babies will instinctively fixate the light
4. Retinoscope is performed monocularly (Fellow eye closed)
Example :
At WD =50 cm
Gross refraction = 4.00 D – 1.00 D × 180
Add adjustment factor = -1.25
Final net refraction = +2.75 – 1.00 × 180

Clinical points not to be missed in Mohindra
retinoscopy:
1. Always darken the room as darkening the room light will aid
patient fixation and concentration.
2. Dim the retinoscope light as dim light doesn’t stimulate
accommodation but bright light will act as good source of
accommodation.
3. Ensure that retinoscope light is kept on the pupil only for short
period of time so as to avoid stimulating accommodation
4. Adjustment factor -1.25 D for school age -1.00D for preschool and
-0.75 D for infants

Clinical pearls while performing
retinoscopy in children's :
If you are unable to get a full prescription on a young child, prioritize the mos
important refractive information:
1. Check if there is astigmatism greater than 1.00D by scanning the meridians
without lenses, looking for significant changes to reflex width, speed and
brightness.
2. Check refractions are equal between the eyes (in all corresponding
meridians if you’ve identified significant astigmatism) without lenses.
3. With loose lenses or a retinoscopy rack, check if the sphere power is
between +2.00D and Plano.

4. Then, if you can, narrow down to get the exact prescription.
 Consider what target you are using in the distance i.e. use something
engaging that makes noise and/or displays lights.
 If children are not under cycloplegic , pay attention to the pupil size.
 A small pupil size is often indicative of over accommodation and you
should suspect moderate hyperopia.
 Have the child sit on their care-giver’s lap.
 Retinoscopy lens racks can be very helpful tools for community screenings,
examination under anesthesia, and children/adults unable to wear the trial
lens frame or sit behind a Phoropter.

If, during retinoscopy,
the fixating eye is the
amblyopic eye, it may
not see the fixation
target (if best corrected
VA <6/60)
The examiner may have
to move further to the
temporal side of the
tested eye
So that it can see the
fixation target although
this increases the angle
of obliquity)
Retinoscopy in Amblyopia

Retinoscopy in Strabismus and
Eccentric fixation:
1. Retinoscopy is ideally performed along the patient's visual axis.
2. In a patient with strabismus, this can be difficult
3. Retinoscopy on the ‘good’ eye must be performed slightly off-axis
4. For the strabismic eye, it can be easier to change the fixation point
for the ‘good’ eye, so that retinoscopy along the visual axis of the
strabismic eye is easier.
5. Alternatively, occlude the ‘good’ eye and perform retinoscopy
slightly off-axis

Where eccentric fixation is present with strabismus, the
examiner must decide whether to refract the fovea or the
eccentric fixating point on the fundus

Retinoscopy in
Nystagmus
Always a challenge
Try retinoscopy in null point
Cycloplegic refraction is best

Dry vs Wet
Retinoscopy
There are certain cases in which
wet retinoscopy is better as
compared to that of dry
retinoscopy.
So we should not miss such
cases in clinical practice.
Accommodative esotropia
All children younger than 3 years
Suspected latent hyperopia
Suspected pseudomyopia
Uncooperative/ non communicative patients
Variable and inconsistent end point of refraction
Visual acuity not corrected to a predicted level
Strabismic children
Amblyopic children
Suspected malingering

 Atropine cycloplegic refraction is advised in the children
younger than 2 years
 Atropine cycloplegic refraction is advised in esotropic children
(accommodative type) up to 4 years
 After 4 years, cyclopentolate cycloplegic refraction is advised
up to 25- 30 years
Clinical pearls for using appropriate drugs:

Dynamic Retinoscopy
Dynamic retinoscopy: Patient is looking at a near object, with
accommodation active
Types of dynamic retinoscopy:
1. MEM retinoscopy
2. Nott’s retinoscopy
3. Bell retinoscopy

Clinical pearls not to be missed during
Dynamic Retinoscopy
Always done binocularly fixing an accommodative target separately
for individual eye.
Done to find accommodative response of a patient
Done over patients habitual distance correction
Always make correct note of working distance and placement
distance of accommodative target while reflex neutralizes
Response must be noted with in a fraction of time i.e quickly
3D target are considered best for dynamic retinoscopy.
As during viewing near target eye converges there might be off axis
retinoscopy.

When to do Dynamic Retinoscopy??
 Accommodative anomalies
 Headache and stress during near work
 Pseudo myopia suspect
 Patient with Esophoria/Esotropia
 Patient with high hyperopia
 Way to find out minus overcorrection in patients

Additional clinical pearls :
1. If the patient has a large pupil, watch the center of the reflex. In dilated
or larger pupil peripheral conflicting shadows will affect the judgement
of reflex
2. Go slower when close to neutralization to identify if the reflex as the
retinoscope beam begins to enter the pupil is entering from the same or
opposite side. If neutral, the pupil will immediately fill with light as the
retinoscope beam crosses the pupil.

4. Hold the retinoscopy rack or loose lens very close to the
patient’s face so not to change the effective power of the lens
Especially important in high refractive errors
5. Careful not to block the eye that is focusing in the distance
with either your head, hand or retinoscopy rack.

6. Scan all meridians before adding any lenses looking for differences in
beam width, speed and brightness – this will help identify astigmatism
before neutralizing the reflexes.
7. Try adding a working distance lens (67cm = +1.50D, 50cm = +2.00D)
into both the right and left lens wells at the back of the trial frame. When
you do this, there is no need to calculate the net result, just remove the
working distance lenses when finished.

8. You must remain on the patient’s visual axis, so ensure you are at
the same height of the patient and using your right eye to assess
the patient’s right prescription and your left eye to assess the
patient’s left prescription.
9. When recording your prescription in negative cylinder, the sphere
is the most plus meridian and the cylinder is the most least plus
meridian.

10. The longer you take to perform retinoscopy the more likely you
are to over minus the patient as you begin to accommodate.
11. Maintain your working distance throughout the entire
procedure and know your working distance
12. When in doubt stay a little with motion.

Accuracy of retinoscopy depends
on following clinical considerations.
Working distance
Always maintain constant distance .using closer distance than
assumed will cause more plus error of less minus error and going
farther will cause opposite effect.
Example:
If a examiner thinks that he is at 50 cm and does retinoscopy from
40cm then retinoscopic error will be + 0.50D more

Scoping off the patients visual axis
 Scoping off axis by 2-3 degree will not cause significant effect in cyl
power and axis also in the spherical power.
 But off axis retinoscopy of angle greater than 5 degree will causes
significant effect on sph and cylindrical power but less effect in
cylindrical axis
Amount of errors for oblique viewing
0.12 DC for 5 degree
0.37DC for 10 degree

Failure to fixate at distance
 Children's may fixate at near and accommodate
 Over minus may be seen
 This can be avoided by reminding child to look at distance
constantly
 Failure to locate principle meridian

Scissors (fish mouth) reflex
 Due to
• large pupil diameter (aberrations)
• Irregular astigmatism
• Irregular retina
• Tilted lens
• Corneal scar
 Neutralized by lens that provides more or less equal
thickness and brightness to the opposing reflex
Problems with Retinoscopy

 High refractive error
 Large pupils (or dilated pupils)
Observation
1. “With” movement in the central part of the ret. reflex
2. “Against” movement in the peripheral part of the ret. Reflex
Retinoscopy Technique
1. Central part of the ret. reflex is considered ignoring the outer par
of the ret. reflex
2. Central part of the reflex must be neutralized

 Small pupils
1. The room lights are made dim and wait for the
pupils to be dilated
2. Reminding the pt. not to look at retinoscope light
3. Mydriatics can be tried
4. Radical retinoscopy is useful

 Corneal scars and opacities/Cataracts /Vitreous opacities
1. Stop the retinoscope light from entering or exiting the eye
2. Scatter light and distort the ret. reflex (make it irregular)
Retinoscopy Technique
 The neutral point is estimated by choosing the brightest ret. Reflex
 Trying to find a “window” through the opacities so that the ret.
reflex can be seen (but be careful not to move too far off axis)

 Mydriatics can be tried
 Radical retinoscopy is useful
 Retinoscopy is done by decreasing the width of beam and
increasing the brightness of the reflex (concave mirror effect)
If the opacity is too dense
- It may not be possible to do retinoscopy

Objective retinoscopy

More Related Content

What's hot (20)

Similar to Objective retinoscopy (20)

More from Bipin Koirala (20)

Recently uploaded (20)

Objective retinoscopy

Editor's Notes