The Lens Thickness (LT) is an important variable in the Holladay 2. It may be obtained with Ultrasound, Lenstar, Scheimpflug (Pentacam) or OCT (Visante). We have found that it is critical in eyes shorter than 22 mm. In eyes longer than 22 mm it has become optional, because the IOL Master does not measure this parameter. The longer the eye, the less important the Lens Thickness … so in a 26 mm eye, it is less important than a 24 mm eye and in a 31 mm eye it is less important than a 26 mm eye and so on.
The IOL Master 700 has Lens Thickness but the 500 and early models do not. In eyes shorter than 22 mm, it is important to have this value, so you must measure it with Ultrasound when this occurs to get the best results. There are other valuable calculations such as Toric IOLs with the EXACT rather than approximate calculation (attachment under Toric Calculators on Page 2), Toric Post Op Back Calculator and many others as you can see from the list of features.
The Pentacam has a HOLLADAY REPORT. On this are the EKR65 which are Equivalent K-readings which can be used on ALL CASES, including post refractive, PKP and accounts for posterior corneal astigmatism.