Final answer:
The two methods mentioned in class for choosing the initial Ortho-K lens are corneal topography and subjective refraction.
Step-by-step explanation:
The two methods mentioned in class for choosing the initial Ortho-K lens are:
- Corneal topography: This method uses a keratometer to measure the curvature of the cornea, which helps in determining the correct lens parameters for Ortho-K.
- Subjective refraction: This method involves the optometrist or eye care professional conducting a subjective assessment of the patient's visual acuity and determining the appropriate lens power based on the patient's responses.
For a better understanding of how light interacts with the eye, we review that light passes through the eye sequentially first through the cornea, then the aqueous humor, lens, vitreous humor, and finally onto the retina. The cornea is the clear, dome-shaped surface that covers the front of the eye and plays a key role in focusing incoming light. The lens of the eye further adjusts the focus, allowing us to see clearly at different distances. Understanding the difference between rods and cones in the eye is also important; rods are responsible for vision at low light levels (scotopic vision) while cones are involved in color vision and function best in relatively bright light (photopic vision).