Trial set (case)

1. TRIAL CASE
PRENTER:- PARESHPRENTER:- PARESH
MHATREMHATRE
MODERATOR:- KUNALMODERATOR:- KUNAL
KISHORKISHOR

2. TRIAL CASE
It contains the set of spherical and cylindrical
lenses of known power.
Components present in Trial set are
o Spherical lenses.
o Cylindrical lenses.
o Prism.
o Accessories.

3. Reduce APERTURE LENSES
 Always Plano convex & Plano concave.
 Diameter of the lens is 20mm.
These lenses probably gives the best
approximation.
Use of the lens is neutralize the spectacle
lens with their opposite sign.

4. FULL APERTURE LENSES.
Full aperture:
Always Bi-convex & Bi-concave.
Diameter of the lens is 38mm.

5. Spherical lenses
Present in plus and minus form
Range: +& -0.12D to +& - 20.00D.
Variation:-
 0.25 to 4.00D in increment of 0.25D
 4.00 to 6.00D in increment of 0.50D
 6.00 to 14.00D in increment of 1.00 D
 14.00 to 20.00D in increment of 2.00D

6. Cylindrical lenses
Present in plus & minus form.
Range:- +&-0.25D to +&-6.00D.
Variations:-
 0.25 to 3.50D in increment of 0.25D
 3.50 to 6.00D in increment of 0.50D

7. Principle:-
Displace image towards apex.
PRISM

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Prisms up to 10 prism diopter with addition of
15to20prism diopter.
Range:-0.50,1,2,3,4,5,6,8,10,12 prism dioptre.
It is Plano thickness gradient prism.

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There are mounted with base apex notation.
 Use:
To measure small squint.
To prescribe prism in spectacle.

10. ACCESSORIES
Trial frame
Jackson cross cylinder
Occluder
Pin hole
Stenopic slit
Maddox rod
Red & Green filter

11. Trial frameTrial frame

12. TRIAL FRAMETRIAL FRAME
It is made up of metallic/plastic frame.
Ideal trial frame features are:-
1.Light weight with comfortable nose rest
2.At least 3 compartment one each for
spherical lenses
cylindrical lenses
occluder

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Compartment of cylindrical lens has smooth and
accurate rotation.
Properties of ideal frame:-
Non allergic material.
Nose bridge & temple are adjustable according
to patient face.

14. JACKSON’S CROSS-CYLINDERJACKSON’S CROSS-CYLINDER
The cross cylinder is a combination of two
cylinders.
Their axis at right angles to each other and
mounted in a handale.
The commonly used cross cylinders are of
+&-0.25 or +&-0.50.
It is used for Astigmatic refraction.

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The cross cylinders usually used to refine
cylindrical axis and power of lens.

16. OCCLUDEROCCLUDER
It is black opaque disc & mounted
in metal/plastic rim.
It is used for uniocular testing and
to occlude light reaching the eye.

17. PIN HOLE

18. PIN HOLEPIN HOLE
Pinhole:-
It is black opaque disc with central pinhole
of 1 to 2 mm.
Ideal central pinhole diameter is 1.42mm.
PRINCIPLE:-
It allowed only one ray of light to passed
through along the principle axis of eye.

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USES:-
To see best corrected visual acuity.
Used for macular function test.
To analyzed opacity of cornea is central or
Para central.

20. STENOPIC SLIT

21. STENOPIC SLITSTENOPIC SLIT
It is made of black opaque with slit aperture.
Slit aperture with 15mm length and 1mm width.
It allowed ray of light to passed through only 1
meridian.

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USES:-
To record V/A in 1 meridian.
To find axis of cylinder.
To find principle meridian.

23. MADDOX ROD

24. MADDOX RODMADDOX ROD
It is the series of high power convex cylinder
mounted with their axis parallel to each other.
This available in red and green colours.
Principle:-
It convert spot light into a line.

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USES:-
To diagnose & measured phoria.
To measure conversion.

26. GREEN & RED FILTERS.GREEN & RED FILTERS.

27. GREEN & RED FILTERS.GREEN & RED FILTERS.
Green & Red filters:-
This are red glasses of 640nm & green 535nm
wavelength.
Red filter in front of the RE and Green filter for the
LE.
Principle:-
This dissociate the eye using colour sense.

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In WFDT. (Worth for dot test)
Diplopia charting

29. Thank you