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Latkany Method.1
The Latkany Method of myopic post-LASIK corneal power estimation is a postoperative
regression method developed by Robert Latkany, et al and published in the Journal
of Cataract and Refractive Surgery1. The advantage of this
method is that it only requires that the surgeon know the refraction prior
to LASIK. This is often helpful if the pre-LASIK refraction can be located
from one source (such as an old pair of glasses), but there are no records
from the keratorefractive procedure available.
This technique applies a regression formula to correct the IOL power calculated
using the flattest K and the SRK/T formula.
The calculated IOL power is then adjusted by the formula:
-(0.47 [Pre-refractive surgery SEq] + 0.85)
The final IOL power is rounded to the nearest 0.50 D.
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-(0.47 [SEq] + 0.85] = Post LASIK IOL power adjustment
 Where...
SEq = The pre-LASIK spherical equivalent in diopters.
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The Latkany Method for the right eye following
myopic LASIK would be carried out as follows:
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If the SRK/T calculated IOL power using the flattest K is +15.21 D for a plano result,
and...
The pre-LASIK spherical equivalent was -5.63 D, then...
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-(0.47 [SEq] |
+ |
0.85) |
= |
Post LASIK IOL power adjustment
|
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|
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-(0.47 [-5.63 D] |
+ |
0.85)
|
= |
1.80 D = IOL power adjustment |
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|
|
|
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+1.80 D |
+ |
15.21 D
|
= |
17.01 D |
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|
|
|
|
|
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17.01 D rounded
to nearest
0.50 D |
= |
17.00 D = |
Final adjusted IOL power. |
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The Latkany Method for the left eye following
myopic LASIK would be carried out as follows:
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If the SRK/T calculated IOL power using the flattest K is +15.66 D for a plano result,
and...
The pre-LASIK spherical equivalent was -5.12 D, then...
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-(0.47 [SEq] |
+ |
0.85) |
= |
Post LASIK IOL power adjustment
|
| |
|
|
|
|
|
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-(0.47 [-5.12 D] |
+ |
0.85)
|
= |
1.56 D = IOL power adjustment |
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|
|
|
|
|
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+1.44 D |
+ |
15.66 D
|
= |
17.10 D |
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|
|
|
|
|
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17.10 D rounded
to nearest
0.50 D |
= |
17.00 D = |
Final adjusted IOL power. |
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Using this technique, the following IOL powers are recommended:
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|
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SN60WF |
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Target Refraction |
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Right |
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+17.00 D |
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Plano |
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|
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+17.50 D |
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-0.38 D |
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Left |
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+17.00 D |
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Plano |
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|
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+17.50 D |
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-0.38 D |
References
1. Masket S, Masket SE. Simple regression formula for intraocular lens
power adjustment in eyes requiring cataract surgery after excimer laser photoablation. J Cataract Refract Surg 2006
32 (3) 430 - 434.
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