Measuring corneal radius with illumination

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    Measuring Radius
AI Thread Summary
The calculation for measuring corneal radius involved using a magnification of 0.0156, leading to an initial object distance of -1538.46 cm and a focal length of 24.38 cm, resulting in a radius of 48.76 cm. However, the average corneal radius is approximately 5 mm, indicating a significant discrepancy. The error was identified as flipping the object and image distances during the calculations. This mistake highlights the importance of correctly assigning distances in optical measurements. Accurate measurements are crucial for understanding corneal dimensions in ophthalmology.
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Homework Statement
An ophthalmometer* is used by optometrists to measure the curvature of a patient’s cornea by shining an illuminated shape on the cornea and measuring the size of the reflected image relative to the object. For one patient, the object was 24 cm from their cornea and the image height was 0.0156 times the height of the object. What is the radius of this patient’s cornea?
Relevant Equations
f = R/2
1/f = 1/i + 1/o
m = -i/o
Since magnification is 0.0156, I have:
m = -i/o
0.0156 = -24cm/o
o = -1538.46 cm

1/f = 1/i + 1/o
1/f = 1/24 cm - 1/1538.36 cm
f = 24.38 cm
R = 48.76 cm

However, when I look up the average corneal radius, the google results show ~5 mm. Did I do something wrong?
 
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Shoot nevermind, I flipped object and image distances.
 
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