Question

In general, we want to fit the Ortho-K lenses with +0.50 to +0.75 ORx endpoint with good acuity. However, there is one lens that is an exception to this rule. What lens is it?

A) Paragon CRT lens
B) Euclid Emerald lens
C) Bausch & Lomb Vision Shaping Treatment (VST) lens
D) Contex OK lens

Answer 1

The Paragon CRT lens does not follow the standard fitting of Ortho-K lenses with a +0.50 to +0.75 ORx endpoint to achieve good acuity. The power of an average human eye ranges from 50.0 diopters to 54.0 diopters, with older adults often requiring reading glasses with positive diopters to correct presbyopia.

Step-by-step explanation:

The lens that is an exception to the rule of fitting Ortho-K lenses with a +0.50 to +0.75 ORx endpoint with good acuity is the Paragon CRT lens.

Discussion on Vision Correction

For an eye with a typical 2.00 cm lens-to-retina distance, the power of the eye ranges from 50.0 D (for distant totally relaxed vision) to 54.0 D (for close fully accommodated vision), which is an 8% increase. An 8% ability to accommodate is typical for people about 40 years old. Younger individuals have a greater ability to accommodate, while older individuals often experience presbyopia, which can be addressed by using reading glasses with positive diopters, typically ranging from 1.0 to 3.5 D.