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Performing Calculations Calculate IOL Screen
Calculating
IOL Power
After Corneal
Refractive
Surgery
The Accutome A-Scan Plus also provides the ability to
calculate IOLs for patients who have had corneal
refratcitve surgery.
Corneal refractive surgery alters the characteristics and
power of the cornea.
*Note: Calculating IOL powers for post refractive surgery
patients is an evolving topic and requires research
and careful planning on the part of the
opthalmologist. The methods and formulas
presented by the Accutome A-Scan Plus for this type
of patient should only be used by a qualified
individual who has done due diligience to determine
the best method, and how to execute that method,
for each patient. If a more appropriate formula or
method for determining the current corneal power is
available, the result of this formula can be used by
selecting the 'Entered' Kpost formula and entering
the power manually.
Double K Method
All IOL formulas, except for the Haigis formula, use the K
measurement in two ways: to know the power of the
cornea, and to help estimate the position of the IOL.
The power of the cornea needs to be the current K of the
patient (post refractive surgery). Estimating the position
of the IOL should be based on the pre refractive surgery
K of the patients. Using both the post and pre corneal
refractive K is called the Double K Method.
When the Rx Surg field is set to Yes, indicating corneal
refractive surgery, the Kpre and Kpost fields are
displayed in the place of K1/K2. Both of these fields must
have data for the formulas to calculate the IOL power.
When using the Haigis formula, the Kpre field is not
shown. The Haigis formula does not use Kpre to
determine the IOL position, the Haigis formula uses the
measured ACD.
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