A patient is prescribed a +15.00D sphere with a fitting distance of 13mm, but the wearing distance is 16mm. What is the compensated lens power that will be supplied?

A patient is prescribed a +15.00D sphere with a fitting distance of 13mm, but the wearing distance is 16mm. What is the compensated lens power that will be supplied?

• A. +15.00D
• B. +14.50D
• C. +14.75D
• D. +14.25D

Answer: (D)

To determine the compensated lens power that will be supplied, it's essential to understand how the fitting distance and wearing distance affect lens power. When there's a difference between the fitting distance and wearing distance, compensation is necessary to ensure the patient sees clearly. In this scenario, the initial prescription is for a +15.00D sphere at a fitting distance of 13mm. However, the patient will be wearing the lenses at a slightly greater distance of 16mm. The change in distance can lead to a change in the effective power of the lens. The formula for calculating the adjustment due to the change in distance is: \[ \text{Compensated Power} = \text{Original Power} - \left(\text{Adjustment Factor} \times \text{Distance Change}\right) \] Here, the adjustment factor is generally taken as -0.25D for every millimeter when moving from a closer fitting distance (in this case, from 13mm to 16mm). The difference in distance is 3mm (16mm - 13mm). Calculating the compensation: \[ 3mm \times -0.25D/mm = -0.75D \] Therefore, the new power to be supplied

To determine the compensated lens power that will be supplied, it's essential to understand how the fitting distance and wearing distance affect lens power. When there's a difference between the fitting distance and wearing distance, compensation is necessary to ensure the patient sees clearly.

In this scenario, the initial prescription is for a +15.00D sphere at a fitting distance of 13mm. However, the patient will be wearing the lenses at a slightly greater distance of 16mm. The change in distance can lead to a change in the effective power of the lens.

The formula for calculating the adjustment due to the change in distance is:

[ \text{Compensated Power} = \text{Original Power} - \left(\text{Adjustment Factor} \times \text{Distance Change}\right) ]

Here, the adjustment factor is generally taken as -0.25D for every millimeter when moving from a closer fitting distance (in this case, from 13mm to 16mm). The difference in distance is 3mm (16mm - 13mm).

Calculating the compensation:

[

3mm \times -0.25D/mm = -0.75D

]

Therefore, the new power to be supplied