Final answer:
The new Ortho-K lens design includes a base curve for central fit, a reverse curve for mid-peripheral fit, an alignment curve for peripheral corneal alignment, and a landing zone curve for edge lift and lens stability, all of which are crucial for comfortable and effective vision correction.
Step-by-step explanation:
The design of new Ortho-K (Orthokeratology) lenses involves four distinct curves, each with a specific role in fitting the lens onto the eye for vision correction. The base curve is central to determining the fit over the cornea's central area, affecting how the lens can reshape the cornea overnight to correct refractive errors such as myopia. The reverse curve is crucial for controlling the fit over the mid-peripheral area of the cornea, facilitating a gradient of pressure that aids in reshaping the cornea. The alignment curve plays a significant role in aligning the lens with the peripheral cornea to ensure a comfortable and effective fit. Finally, the landing zone curve determines the edge lift and maintenance of the position of the lens on the eye, which is essential for the lens's stability and overall comfort.
Each curve in the Ortho-K lens design aims to provide a means to correct vision by reshaping the cornea. For instance, in the case of myopia or nearsightedness, the cornea is flattened to reduce its refractive power, whereas, for hyperopia or farsightedness, the curvature of the cornea is increased.