Aspheric Back Surface
Ellip-See-Con® is a GP contact lens with an aspheric posterior surface.
This posterior surface gradually flattens, similar to the flattening of the corneal surface, from apex to periphery. The Ellip-See-Con® design will enable you to successfully fit more challenging GP candidates. This design has proven to be an excellent problem solver. The aspheric back surface provides a more uniform tear film and minimizes localizing bearing points. This improved lens to cornea relationship provides improved comfort and more efficient masking of corneal astigmatism. The fitting of spherical, astigmatic and other challenging cases become more clinically and economically feasible with Ellip-See-Con® lenses.
Corneal Astigmatism
0.00 - .050 D
0.75 - 1.50 D
1.75 - 2.75 D
3.00 or more
Base Curve
.50 D Steeper than Flat K
.75 Steeper than Flat K
1.00 Steeper than Flat K
1.25 D Steeper than Flat K (Consider Toric)
Ellipsoidal
No pronounced junctions
to create pressure points
Spherical
*Maximum pressure during
lid closure at junction of base
curve and peripheral curve.
Ellipsoidal lenses provide even
distribution of bearing pressure.
Fitting Procedure
The back surface of the Ellip-See-Con® lens is flattening from the center to edge. The rate of flattening (eccentricity) has a direct effect on the sagittal depth and lens to cornea relationship. In order to accommodate the base curve flattening, the base curve should be selected steeper than the flattest corneal meridian. Corneal astigmatism will also have a significant effect on your final base curve selection as follows:
Diameter Selection
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An average lens size for the Ellip-See-Con® design is 9.2mm.
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Larger or flatter corneas may require a lens diameter of 9.6mm or larger.
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Smaller or steeper corneas may require a lens size of 8.8mm or less.
Over-Refraction
Once an acceptable fit is achieved, over-refract to determine the final lens power.
ESC Trial Lens Evaluation
The optimum Ellip-See-Con® fit will be central to central superior. Intrapalpebral or upper lid attachment are both acceptable fitting techniques. Low riding lenses should be avoided because thet tend to inhibit proper lens movement and tear exchange.
Good Fit: Fluorescien pattern should appear aligned to slight clearance over the corneal apex. Mid-peripheral fluorescien will appear thinner than the apical pattern but still in general alignment with the mid peripheral cornea. A more prominent band of fluoroscein should be present as the edge-lift increases to the lens edge.
A flat base curve will touch at the corneal apex, represented by a lack of fluorescein. A flat lens may also move excessively and de-center between blinks. If these symptoms are present, begin steepening the base curve in .10mm steps and re-evaluate.
A steep fitting base curve will seal off and show a band of ring touch in the mid-periphery and trap excessive fluorescein centrally. Lens position may be low with minimal movement during blink. If these symptoms are present, begin flattening the base curve in .10mm steps and re-evauate.
