You are in the midst of performing a manifest refraction on a patient with keratoconus. You are determining the cylinder power and the patient seems to want more than 6 D of cylinder. What can you do at this point to obtain the most accurate estimate of his cylinder power?
Refractometry
No
U
C
In most phoropters, the cylinder power only goes up to 6 diopters. However, you can snap in an auxillary cylinder lens (see photo below) to add even more cylinder power into the phoropter.
Individuals with keratoconus frequently have very high levels of astigmatism. Thus, this is a very common situation for these patients.
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