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IOL Power Calculations
Cataract Surgery Arizona

Adding IOL Correction Factors.

When performing A-scan ultrasonography on a pseudophakic eye at a velocity of 1,532 m/sec, add the corresponding correction factor to the axial length displayed to get a close approximation of the true axial length. The correction factors for acrylic and PMMA lenses will be positive and the correction factors for silicone lenses will be negative.

The best accuracy is obtained by multiplying the proper conversion factor (+0.30 for acrylic, -0.56 for silicone and +0.45 for PMMA) by the acutal center thickness of the intraocular lens implant. Center thickness information can usually be obtained directly from the lens manufacturer.

Cataract Surgery Arizona
IOL
Power
Acrylic
5.5 mm
3 Piece
Acrylic
6.0 mm
3 Piece
Silicone
Plate
Haptic
Silicone
6.0 mm
3 Piece
PMMA
5.5 mm
1 Piece
PMMA
6.0 mm
1 Piece
PMMA
6.5 mm
1 Piece
+10.0 D +0.14 +0.18 -0.43 -0.50 +0.18 +0.23 +0.23
+12.0 D +0.14 +0.18 -0.45 -0.52 +0.20 +0.25 +0.26
+14.0 D +0.14 +0.18 -0.48 -0.54 +0.21 +0.28 +0.30
+16.0 D +0.18 +0.22 -0.51 -0.55 +0.23 +0.30 +0.33
+18.0 D +0.18 +0.23 -0.54 -0.56 +0.24 +0.33 +0.37
+20.0 D +0.20 +0.25 -0.57 -0.59 +0.27 +0.36 +0.40
+22.0 D +0.20 +0.26 -0.60 -0.60 +0.30 +0.39 +0.43
+24.0 D +0.22 +0.27 -0.63 -0.62 +0.33 +0.41 +0.47
+26.0 D +0.23 +0.29 -0.66 -0.64 +0.36 +0.44 +0.51
+28.0 D +0.24 +0.30 -0.69 -0.65 +0.39 +0.46 +0.55
+30.0 D +0.25 +0.31 -0.71 -0.67 +0.41 +0.50 +0.59