Final answer:
Various contact lens designs, such as aspheric, Soper, and tangent streak lenses, can be considered when fitting a patient with keratoconus. Cataracts diffuse light, leading to blurred vision. During laser eye surgery to repair retinal tears, parallel laser light rays are necessary to focus precisely on the retina.
Step-by-step explanation:
The question asks about the types of contact lens designs that might be considered for a patient with keratoconus, which is a condition where the cornea (the clear front part of the eye) thins and bulges into a cone-like shape. The types of contact lenses that could be considered for fitting a keratoconus patient include:
- Aspheric lenses which are designed to provide a more uniform visual performance across the lens and can compensate for the irregular shape of the cornea.
- McGuire lenses is a specific type of lens not commonly recognized. It may refer to a custom or specialty lens, but without more context, this is unclear.
- Soper lenses are specifically designed for keratoconus patients and have a design that can help manage the cone shape of the cornea.
- Tangent streak lenses have a flattened area designed to align with the steepest part of the cornea which can aid in fitting on eyes with keratoconus.
In the case of cataract, the condition causes light to be diffused as it passes through the clouded lens, leading to blurry vision. When performing laser surgery to repair a retinal tear, the laser light rays entering the eye must be parallel to ensure that they focus accurately onto the retina and provide the precision required for spot-welding.