Swanson Nomogram

Indications for use:

IntacsŪ inserts are indicated for the correction of low to moderate myopia in patients who are 21 years of age or older with a cycloplegic sperical equivalent (SE) refraction between -0.50 to -5.00 diopters with less than 1.00 D of astigmatism.

IntacsŪ inserts are manufactured from polymethylmethacrylate (PMMA). The product is available in 11 sizes which range from 0.210 mm to 0.450 mm in thickness. The following chart relates INTACS inserts product thickness with the predicted dioptic correction.  Notations underlined in RED denote U.S. FDA approved sizes.

IntacsŪ Myopia & Post Lasik Ectasia Nomogram
IntacsŪ Inserts Thickness (mm)	Predicted Nominal Correction	Predicted Average Correction (D)
0.210 mm	-0.75 D	-0.500 to -0.875 D
0.230 mm	-1.00 D	-1.000 to -1.125 D
0.250 mm	-1.30 D	-1.250 to -1.500 D
0.275 mm	-1.70 D	-1.625 to -1.750 D
0.300 mm	-2.00 D	-1.875 to -2.125 D
0.325 mm	-2.30 D	-2.250 to -2.500 D
0.350 mm	-2.70 D	-2.625 to -2.750 D
0.375 mm	-3.00 D	-2.875 to -3.125 D
0.400 mm	-3.40 D	-3.250 to -3.500 D
0.425 mm	-3.70 D	-3.625 to -3.875 D
0.450 mm	-4.10 D	-4.000 to -4.250 D
* The 0.210 mm, 0.230 mm, 0.375 mm, 0.400 mm, 0.425 mm and 0.450 mm IntacsŪ Inserts have not been approved for use in the U.S. International Use: Myopia nomogram (spherical equivalent) same size Intacs for post Lasik Ectasia

Patient selection considerations:

Patients with large dilated pupil diameters (> 7.00 mm) may be predisposed to low light visual symptoms (such as glare and halos) postoperatively and should be appropriated advised.

Swanson Nomogram for Centered Cones (POsterior Float 50% within the the 3 mm optical zone)*
Spherical Equiv	IntacsŪ Size	Notes:
+1.00 to -2.00	.250 mm	Steep refractive axis incision technique spherical equivalent On thicker corneas > 500 microns use the next thicker segment on the nomogram.
-2.00 to -3.00	.300 mm
-3.00 to -4.00	.350 mm
-4.00 to -5.00	.400 mm*
-5.00 and higher	.450 mm*
*Keratoconus, Post-Hex, RK and AK Ectasias and Post-Incisional Unstable Cornea

De-Centered Cones (Posterior Float 50% outside the 3 mm optical zone)**
Spherical Equiv	Inferior IntacsŪ	Superior IntacsŪ
+1.00 to -2.00	.250 mm	.300 mm
-2.00 to -3.00	.250 mm	.350 mm
-3.00 to -4.00	.300 mm	.400 mm*
-4.00 and -5.00	.300 mm	.450 mm*
-5.00 and higher	.350 mm	.450 mm*
**Keratoconus, Pellucid Marginal Degeneration or "Pellucid Like" Nomogram
Important Pearls: Hydrate the cornea constantly after marking the eye Tight 10-0 nylon suture for 60 days for Keratoconus & Pellucid Marginal Degeneration The Intacs create a 2nd limbus and a coupling effect The Intacs will flatten the steepest meridian the most Light 10-0 nylon suture for 10 days for Myopia: Incision must be approximated Light 10-0 nylon suture for 30 days for Post Lasik: Incision must be approximated Incision for Pellucid or Pellucid Like will likely occur at the horizontal axis on top the "crab claw" or tops of pigeon heads