Advanced FAQ

This is a compilation of Dr Holladay's email answers that Andrew compiled. For the most part Dr Holladay just answers the questions that Andrew can't. So, therefore, the answers below are not well understood by Andrew.

We have recently upgraded our software due to a computer change and our reports now say “Right” and “Left” instead of the previous “OD” and “OS”. We have a physician(copied on this email) asking if we can change it back to the OD/OS style. I have looked at all the settings seemingly available and am not able to discern any place to make this change.

Mistakes are made in the OR by operating personnel that are not familiar with ophthalmic terms such as OD and OS, so JCAPHO, ASOA and DICOM {(Digital Imaging and Communications in Medicine) is a standard for handling, storing, printing, and transmitting information in medical imaging. It includes a file format definition and a network communications protocol.} have all recommended changing to Right and Left (rather than OD and OS) to avoid mistakes.

We have simply complied with these latest recommendations.

Have you added a way to calculate IOL power in Lasik patients using corneal power measurements with OptoVue

When you check the PREVIOUS REFRACTIVE SURGERY SCREEN an ALT K-BUTTON appears and when clicked shows the screen below. This allows you all available options (Historical, Contact Lens, Average from Preop and the last can be used with Optovue Topographer. There will be a 3 mm zonal value (not sim K, but for the entire 3 mm zone). Doug Koch and Dr Holladay showed that if you take the 3 mm zonal value and subtract 15% of your best guess of the refractive change (example -6.00 D to plano (-6.00 X 15% = -0.90 D), so if the 3 mm zonal value were 40 D, the Surgeon entered value would be 40 – 0.90 = 39.10 D. Whichever radio button is checked is the one that the Program uses for the K in the vergence formula.

The K used to SIZE THE EYE is the one ENTERED on the HISTORICAL METHOD (example 46.0 D in this case) and this is what is used for the ELP (Effective Lens Position). If no value is entered, the 43.86 D is used (average of human population). This has recently been referred to as the Double K method, which has been in the Program for over 15 years.

If I have an aphakic patient, should I put their +13 aphakic Rx in the preop RX? The IOL power changes 1 diopter when I do this. Which is correct?

Yes, but you need to check “Other Calculation” (as below) and then when you click (click here), check the APHAKIC EYE, select bag or sulcus and enter the PREOP PHAKIC REFRACTION before they became APHAKIC. By clicking STANDARD IOL (Cataract Removal), you are telling the PROGRAM that the PHAKIC REFRACTION was +13.0. You may also compare the IOL RECOMMENDED by changing to the HOLLADAY R (REFRACTION) on the IOL CALC SCREEN and see how it compares with the Holladay 2 from AXIAL LENGTH. The latter is usually more accurate, due to the error in the actual vertex distance from the REFRACTION.

We have a patient for surgery that has silicone oil in the eye. I have already made the Axial Length correction on the IOL Master for the oil. When I enter his information into the Holladay II software, should I still check the box under pre-existing condition Silicone Oil in Vitreous Cavity even though the correction has already been made to the length? I have entered it both ways, with and without checking the box and it is a difference of about 7.5 diopters between the two…

You have the correct axial length, but the real question is whether the silicone oil will be removed at the time of cataract surgery or shortly thereafter. If the silicone oil is to remain in the eye, the you must check silicone oil in the Vitreous Cavity, to compensate for the difference in refractive index. If the silicone oil is removed then you do not check this box.

Is the use of the Holladay Equivalent K readings from the Pentacam mandatory with post-refractive surgery patients when calculating the required IOL strength with the IOLMaster and Holladay 2 formula?

Yes … the corneal power must be correct with any IOL Formula including the Holladay 2 to get accurate results. The following description explains how to get the correct Ks from the Pentacam. Everything else is the same as a normal patient.

Is the accuracy of the Holladay 2 formula (in particular, when used with the IOLMaster) compromised when the pre-LASIK/LASEK refraction or CVD is unknown?

The accuracy of an IOL Calculation is ALWAYS COMPROMISED when refractive surgery is performed, due to the induced multifocality of the cornea. Performing the Historical Method (pre-refractive data) is helpful for a second method of the confirming the 65% EKR, but the latter is still better. If you get the same answer, then you know it is correct, but this rarely occurs.