The tear pattern is similar to spherical Paragon CRT® lenses with uniform mid peripheral alignment 360° and appropriate edge lift
- Excessive superior decentration is due to insufficient sagittal height (too flat).
- Consider increasing sagittal height by increasing the RZD 25 microns in both the flat and steep meridian.
Example: If the current lens is;
8.60/525 / 575/-33 change to
8.60/550 / 600/-33
- Excessive inferior decentration is due to excessive sagittal height (too steep).
- Consider decreasing sagittal height by decreasing LZA 1 degree (if a single LZA is used).
Example: If current lens is;
8.40/525 / 575/-33, change to
8.40/525 / 575/-32
Insufficient applanation is due to excessive sagittal height.
First - Decrease the LZA by 1 degree, if a single LZA is used.
Second - Decrease the RZD by 25 microns in both meridians.
A vision condition in which light rays are spread over a diffuse area rather than sharply focused on the retina.
The transparent anterior portion of the sclera, about one-sixth of its surface. It is anterior to the aqueous humor, the iris, pupil and lens of the eye. The cornea is the first part of the eye that refracts light. It is composed of 5 layers: an epithelial layer, Bowman's membrane (anterior limiting membrane), the substantia propria corneae, vitreous membrane, and a layer of endothelium. Beyond the edge of the cornea is the sclera (the white of the eye).
Also called orthokeratology or ortho-K; the therapeutic process of wearing special contact lenses overnight that gently alter the curvature of the cornea to temporarily correct myopia and less commonly, astigmatism, hyperopia, or presbyopia.
The outermost tissue layer of the cornea, approximately 50 microns in thickness.
A vision condition in which light rays are focused behind the retina, enabling the person to see clearly in the distance but close vision is blurred; farsightedness.
Myopia, or nearsightedness, is a visual condition in which light rays are focused in front of the retina, enabling the person to see clearly for a short distance, but long distance vision is blurred.
Hyperopia and impairment of vision due to advancing years or to old age; it is dependent on diminution of the power of accommodation from loss of elasticity of the crystalline lens, causing the near point of distinct vision to be removed farther from the eye
Unlike the traditional convex shape of contact lenses, reverse geometry designs incorporate a 4-curve design, including the base curve/treatment curve, reverse curve (deeper than Base Curve), alignment/fitting curve, and a peripheral curve.
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