#About Trial set #A to Z about trial frame & trial lenses #Accessories of trial set #Basic idea about uses of accessories

1. ACCESSORIES OF TRIAL SET
Md.Azizul Islam
Junior Optometrist (Oculoplasty Dept:)
Ispahani Islamia Eye Institute & Hospital
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2. Declaration
I have no financial interest by
presenting this presentation
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3. Lay out of Presentation
TO KNOW ….
About Trial set
A to Z about trial frame & trial lenses
 Accessories of trial set
Basic idea about uses of accessories
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4. Trial Box
 Trial Box is a clinical examination used by orthoptists,
optometrists and ophthalmologists to determine a
patient’s need for refractive correction, in the form of
glasses or contact lenses. The aim is to improve current
unaided vision or vision with current glasses.
 Trial set mainly consists of positive and negative sphere
lens, positive and negative cylinder lens, prism lens and
accessory lens etc. According to different usage, there're
basically 68 lens set, 90 lens set, 104 lens set, 158 lens
set, 232 lens set and 266 lens set.
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5.  OBJECTIVE REFRACTION
 SUBJECTIVE REFRACTION
 DIPLOPIA CHARTING
 DIAGNOSIS OF SQUINT
 ASSESS BINOCULAR VISION
USES of Trial Box

6. TRIAL FRAME
TRIAL LENS
PRISM
OTHER ACCESSORIES
PLANO LENS
RED AND GREEN FILTER
MADDOX ROD
STENOPIC SLIT
OCCLUDER
PIN HOLE
JACKSON CROSS CYLINDER
NEAR VISION CHART
Accessories Of Trial Set

7. Trial frame an eyeglass frame
designed to permit insertion of
different lenses used in correcting
refractive errors of vision.
 4-5 compartments
 1st - High powered Lens
 2nd - spherical lens
 3rd - cylindrical lens
 4th - accessory lens & prisms
TRIAL FRAME

8. FULL APERTURE FRAME : Accommodates up
to five, 38mm lenses for each eye. Independent
screw adjustments for PD of 48 to 80mm.
REDUCED APERTURE FRAME: It holds up to
four, 38mm lenses for each eye. Accessories
may be easily inserted and extracted.
HALF EYE TRIAL FRAME : Half eye trial
frame with nosepiece for child. PD of 54 to
58mm & Available for adults with PD 59 to 67
mm.
TYPES TRIAL FRAME

9. Full Aperture Reduced Aperture
Half eye
TYPES TRIAL FRAME

10. TRIAL LENS
FULL APERTURE LENSES :
Approximately 38 mm diameter.
Biconvex or biconcave form.
 REDUCED APERTURE LENSES :Lenses
of 20 mm diameter mounted in the
metal rim of 38 mm diameter. It also
Biconvex or biconcave form .
 During refraction the practitioner utilize a set of
known lenses called as Trial lenses.

11. • All meridians have same power.There are (±) 32/40
pairs of spherical lens in plus & minus power.
POWER RANGE IN SPHERICAL(IEH)
 Pair of positive lenses ranging (±)0.12 to 20.00DSP
 0.12 DSP
 0.25 DSP to 4.00 DSP in 0.25 steps
 4.00 DSP to 6.00 DSP in 0.50 steps
 6.00 DSP to 14.00 DSP in 1.00 steps
 14.00 DSP to 20.00 DSP in 2.00 steps
POWER RANGE IN SPHERICAL (An Ideal)
0.25 DSP to 6.00 DSP in 0.25 steps
 6.00 DSP to 10.00 DSP in 0.50 steps
 10.00 DSP to 16.00 DSP in 1.00 steps
 16.00 DSP to 20.00 DSP in 2.00 steps
SPHERICAL LENSES

12.  For spherical ametropia
 For hand neutralization
 Checking the
refracting error
USES SPHERICAL LENSES

13. Power lies in one meridian. Axis meridian is
marked on rim of the lenses. (±) 20 pairs of CYL
Lenses.
 POWER RANGE IN CYLINDER LENSES(IEH)
Pair of negative lenses ranging (±) 0.12 to 6.00D
 0.12 CYL
 0.25 CYL to 3.50 CYL in 0.25 steps
 3.50 CYL to 6.00 CYL in 0.50 steps
POWER RANGE IN CYLINDER LENSES(An Ideal)
0.12 CYL
0.25 CYL to 4.00 CYL in 0.25 steps
 4.00 CYL to 6.00 CYL in 0.50 steps
CYLINDRICAL LENSES

14.  For hand neutralization
 For correction of
astigmatism
 For checking the
refractive error
USES CYLINDRICAL LENSES
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15. Prism is a refractive medium having two plane surfaces
inclined at an angle. Principle :- “1 prism diopters
produces displacement of the image at 1 cm when the
object is situated at the distance at 1m.” Its For the
measurement and correction of the angle of deviation &
Correct & measure Strabismus . 10 /12 pcs
Power range of :
½(0.5)D
1- 6.00D in 1D steps
6- 12.00D in 2D steps
PRISM
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16. PLANO LENS
RED AND GREEN FILTER
MADDOX ROD
STENOPAIC SLIT
OCCLUDER
PIN HOLE
JACKSON CROSS CYLINDER
NEAR VISION CHART
ACCESSORIES
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17.  Zero power 1/2 pcs lens
It is used for satisfy &
identify the malingering
patients.
PLANO POWER LENS
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18. Red-Green filters
 Red in RE & Green in LE
 Used for color dissociation
 Used to find out
suppression of eyes
 To find out diplopia
 To worth 4 dot test &
FRIEND test
 Used to measure the
Fusion , squint
 Red-Green filters also
used to cheek colour sense
of the retina before cat Sx.
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19. Maddox Rod
It is made up of several
series of high plus
Plano cylindrical lenses.
5-6 cylinders of red,white
or green glass prisms.
 Its help ……
To detect heterophoria
-To detect cyclophoria
-To detect orthophoria
As macular function test.
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20. Stenopic Slit
The stenopic slit found in all
the trial sets is 1-2 mm by 15-35
mm in size. It splits an opaque
disc into two halves. It is
useful in finding out the axis
of the cylinder . Black opaque
disc with vertical / horizontal
straight slit at centre To
differentiate causes of haloes
Fincham’s test
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21.  It is an opaque plastic disc
 Occlude one eye
 To relax accommodation
 Used to dissociate fusion &
Used to close one eye ,while
the other eye can be tested for
visual acuity.
CCLUDER
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22.  Opaque disc with pinhole of
1-2 mm diameter in its centre.
 Allows only a pencil of light
pass through the corneas.
 Helps to determine whether
eye has refractive or
pathological errors.
 Pinhole of 1.32 mm is more
effective.
 Usually available pinhole is
1mm in ordinary trial set.
Pin Hole Disc
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23. Jackson Cross Cylinder
JCC used to find used to determine the
cylindrical axis and the cylindrical power
for the patient.
In a cross-cylinder the axes are 45 and 135
degree.
We turn the axis 5 degrees towards it and
the opposite if the patient wears a negative
one instead. Principle: spherical
equivalent is zero
 Used to determine both power & axis of
the astigmatic correction
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24. • It is was introduced by
Snellen.It is a photographic
reduction of Snellen’s
distant chart.
Uses :-
Mainly used for visual
acuity.
Also used to measure the
near point of
accommodation.
Record near vision @ 33 cm
to 40cm, N6 is normal vision
@ near.
NEAR VISION CHART
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25. Take Home Messages
Trial Box is a clinical examination
used by orthoptists, optometrists
and ophthalmologists.
240 & 266 pcs lens set is ideal.
 Trial frame has 4-5 compartments
SPH : All meridians have same power
CYL: Power lies in one meridian
Thickest Side is the Base of prism
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26. References
Khurana. (2008). Theory and Practice of Optics
and Refraction (2nd ed.)
Clinical Procedures in Optometry
A Hand Book of Basic Optometry & Refraction
http://medical-
dictionary.thefreedictionary.com.
Picture : Me + Internet (Google)
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