Soflex toric lenses
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Transcript of Soflex toric lenses
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SSoflexoflex
Toric LensesToric Lenses
By
Moodi Kuperman B.Sc.
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Astigmatism is the most common refractive problem. It is a vision problem that causes objects to appear distorted and blurry. It often affects both distance and near vision. It is the most common vision problem and it may occur with nearsightedness and farsightedness.
AstigmatismAstigmatism
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AstigmatismAstigmatismAstigmatism is mostly caused by the cornea having an oblong shape, like a football, instead of spherical shape, like a basketball. A cornea with astigmatism has two curves, one flat curve and one that is steep. Light is then focused at two points instead of one. One point of focus may be in front of the retina and the other behind. This causes images to appear distorted in addition to appearing blurry.
Astigmatism may also be caused by an irregularly shaped crystalline lens. This condition is termed "lenticular astigmatism."
More then 40.0% of the population has astigmatism of more than 0.75DS
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Corneal cylinder
Lenticular cylinder
Combination cylinder
Type of Astigmatic CasesType of Astigmatic Cases
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1. Corneal:All the value of the cylinder is from the cornea :
CYL=Rh - Rv (in diopter)
Type of Astigmatic CasesType of Astigmatic Cases
Back toric lens is recommend to correct this type of cylinder.Front toric is a limited choice
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2. Lenticular: All the cylinder is from the internal part of the eye.
Only Front Toric lenses can correct this type of cylinder.
Type of Astigmatic CasesType of Astigmatic Cases
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3. Combination Cylinder: The Cylinder is vectors sum of the corneal and the lenticular astigmatism.
The same direction
Correct with back & front toric lens
Opposite direction
Correct with back & front toric lens
Opposite direction
Correct with front toric lens
Different direction
Correct with front toric lens
corneallenticulartotal
Type of Astigmatic CasesType of Astigmatic Cases
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How to correct astigmatism?
Using of: Spectacles
Contact lenses
Operation• Lasik• Intacts• IOL
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How can contact lenses help?
Contact lenses help by correcting the distortion of the corneal shape. Considerable advances have been made in correcting astigmatism by contact lenses.
Today various types of contact lenses are available to correct almost all types of astigmatism.
Contact lenses are better than the conventional eye glasses in correcting some astigmatism cases.
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Types of contact lenses used to resolve astigmatism:
Material Lens type Cyl source SizeSoft Spheric Corneal Up to -1.00DC
Back toric Corneal Any
Front toric Any Up to -2.50DC
GP Spheric Corneal Up to -2.75DC
Back toric Corneal Any
Front toric Any Up to -2.50DC
Bi toric Combination Any
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SOFLEX Soft Back Toric lensesSOFLEX Soft Back Toric lenses Toric Lite® , Trios, SH Toric (Silicone Hydrogel)
Back toric lens Prism ballast stabilization Large range of parameters Superb comfort High reproducible rate Excellent visual acuity
NO’ 1
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Back Toric Lens DesignBack Toric Lens Design
Peripheral curve
Lenticularcarrier curve
Anterior optic zone Lens
mark
Eccentriclenticular zone Toric
optic zone
Spherical fitting curve
Dt = 14.5mm
Boz =8.6mm
Foz =8.7
Front surface Back surface Cross-section
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Back Toric Lens DesignBack Toric Lens Design Stabilization with Prism ballast
1 2 3
prism Back toricUp thinDown thick
Force the lens down by gravity
Force the back toric structure to fit the corneal astigmatism
Force the lens down in each blink
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Lens Parameters:Lens Parameters:
Base Curve Range: 8.1 , 8.4 , 8.7 , 9.0 , 9.3
Diameter: 13.5 , 14.50 , 15.0 mm
Sphere Power Range: ANY
Cylinder Power: ANY
Axis: ANY
Effective Optic Zone: 9.00 mm
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Toric-Lite / Trios - Lens MaterialsToric-Lite / Trios - Lens Materials
GM3 – 58% water content hydrogel material
provides :
Extreme comfort Water retention Low modulus Deposit resistance Durability Increased moisture during wear
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SH Toric - Lens MaterialsSH Toric - Lens Materials
DEFINITIVE – 74% w/c Silicon Hydrogel material
provides :
Extreme comfort High Oxygen permeability Water retention Low modulus Deposit resistance Durability Increased moisture during wear
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Fitting Procedure: Fitting Procedure:
Patient History along with Normal Slit Lamp Evaluation for C/L
Corneal / topography measurements Rh/axis , Rv evaluate the type of the cylinder:
Corneal, Lenticular or CombinationBack toric design works the best where most of the cyl. is corneal.
Base curve : Kflat + 0.8 to 1.0mm for the Toric Lite / TriosKflat + 0.5 to 0.7mm for the SHToric
Spectacle Rx
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Fitting Procedure: Fitting Procedure: cont.cont.
Correction for the back vertex for the sphere and for the cyl.
For hyperops, add +0.25DS to the sphere For accurate results, when fitting hi-myopes or hi-
hyperops cases, it is recommend to fit first one day disposable lens with the closest sphere power (B.V.P) and then to do over refraction
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SOFLEXSOFLEXToric Lens Calculator
Advanced PC program for calculating the Soflex Toric lenses that takes into account as much parameters as possible:• The type of the cylinder• Size of the cornea• Atmosphere (dry or wet)• Input parameters:
Diopter or mm + cyl or – cyl
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Toric Lens CalculatorToric Lens Calculator22
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Fitting Example:Fitting Example:
Rh= 7.94 (42.50DS)Rv= 7.42 (45.60DS)42.50 / 45.60 X 165o
Rx= -6.25/-3.00x165o
Order
7.94+1.0 = 8.94B.C. = 9.0mmthe cyl is corneal.
-5.75/-2.50x165o
Toric Lite 14.5 9.0(SH Toric 14.5 8.7)-5.75/-2.50x175o
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Troubleshooting:Troubleshooting: When the vision is not satisfactory : 1. Re-check your fitting. 2. Over refract,
and calculate Cross Cyl. and order new lens. Where lens does not
stabilize - change BC Where lens rotates
recalculate according to the L A R S rule
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The L A R S Rule:The L A R S Rule: LLeft eft AAdd dd RRight ight SSubtractubtract
Left Movement
Lens Axis to Order:Cyl axis + Movement axis Cyl axis
Right Movement
Cyl axis + Movement axis
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Fitting Tips:Fitting Tips:
The lens can mask axis error up to ±8o
Order diameter 13.5 / 15.0 when cornea has small / big diameter or according the eye lids space
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CDGM3 – FT / SH SPHERE - FTCDGM3 – FT / SH SPHERE - FTFront Toric hydrogel lensFront Toric hydrogel lens
When the cylinder source is lentiqular or combinate use the Front Toric lens design
Front toric lens Prism ballast stabilization Large range of parameters Superb comfort High reproducible rate Excellent visual acuity
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Lens Parameters:Lens Parameters:
Base Curve Range: 7.6 to 9.0 @ 0.2mm steps
Diameter: 13.5 , 14.50 , 15.0 mm
Sphere Power Range: ANY
Cylinder Power: 0.25 to -2.75 @ 0.25D steps
Axis: ANY
Effective Optic Zone: 9.00 mm
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Lens CareLens Care
Daily cleaning Daily disinfecting with proprietary brands of: - hydrogen peroxide system - one step system - multi purpose solution system
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THANK YOU THANK YOU VERY MUCH !!VERY MUCH !!
QUESTIONS PLEASE