Published on June 8, 2016
1. By: Noor Munirah binti Awang Abu Bakar Optometrist (MOC No: O-0869) IOL Calculation: Holladay 2
2. Generations First – SRK 1 & Binkhorst Second – SRK 2 Third – SRK-T, Hoffer Q, Holladay 1 Fourth- Holladay 2 & Haigis
3. Holladay 2 History IOL calculation formula Recommended formula usage
4. Holladay 2: History IOL power calculations were first developed over 100 years ago. First generation: “single variable” formulas Measurement of axial length An assumed anterior chamber depth (ACD) of 4.5 mm Third generation: 1988-Holladay 1 formula added keratometry to offer the first “two variable” formula, which helped improve accuracy in short and long eyes. Holladay 1, Hoffer Q, SRK-T : Assumed anterior segment size was directly related to axial length resulted in “surprise” outcomes esp in small eye
5. Holladay 2: History In 1993, Dr Holladay led a worlwide study involved 34 cataract surgeons to determine which of 7 variables were relevant for predictors of effective lens position (ELP). A large data set of from 34,000 eyes was collected and analyzed to determine relative significance of each variable, as shown in Figure 1. Findings: 1. “We were surprised to learn that horizontal white-to-white measurements emerged as the next most important variable relate to ELP after axial length and Ks,” remarked Dr. Holladay. 2. “We also proved that there is almost no correlation between axial length and size of the anterior segment in 80- 90% of eyes.”
6. Holladay 2: History The results from this study : led to the release of Holladay 2 formula. Invention of an easy-to-use program that allowed for data entry of the new variables and instant calculation of Effective Lens Position (ELP) and the appropriate IOL power selection (aka HIC.SOAP). Led to a new paradigm of evaluating eyes by both their axial length (short, normal, long) and their anterior segment size (small, normal, large).
7. Holladay 2: History There are now nine eye types – not just three – that could be used to classify a given patient’s eye (Figure 2). The WTW measurements demonstrated that: •Short axial length eyes (<21 mm), 80% would be considered normal and 20% would be considered small in terms of anterior segment size. •Normal axial length eyes (21-26 mm) had an equal distribution of eyes being of either large (2%) or small (2%) anterior segment size. •Long axial length (>27 mm). 90% would be considered normal and 10% considered as large in terms of anterior segment size.
8. Holladay 2: IOL calculation formula Holladay 2 formula determines Effective Lens Position (ELP) using 7 parameters : All 7 parameters can be used to calculate IOL power by input into Holladay IOL Consultant & Surgical Outcomes Assessment Program (HIC.SOAP).
9. Holladay 2: IOL calculation formula Holladay IOL Consultant & Surgical Outcomes Assessment Program (HIC.SOAP). Traditionally, 5 variables can be measured with: ACD, LT & AL : Standard ultrasound biometry. K & WTW : Autokeratometer or corneal topography
10. Holladay 2: IOL calculation formula
11. Holladay 2: Recommended formula usage Holladay 2 formula has been considered as one of the most accurate IOL formula today. (Srivannaboon et al. 2013) Holladay 2 has emerged as the “state of the art” IOL calculation formula and today is the leading formula used by US surgeons. (Hill, 2005) Holladay 2: Currently most sophisticated formula Accuracy Predictability
12. Holladay 2: Recommended formula usage •This formula has been found to be highly accurate for a large variety of patient eyes.
13. Holladay 2: Recommended formula usage The IOLMaster 500 by Carl Zeiss is the only instrument on the market that has the Holladay 2 formula inside the unit. IOLMaster 500 The ZEISS IOLMaster® 500 is the gold standard in optical biometry. It measures: 1. Axial length 2. Corneal radii/ power 3. White to white 4. AC depth Formula: Holladay 1, Holladay 2, Haigis, SRK 2, SRK-T, Hoffer IOL measurement instruments need to transfer the data to an external computer as well as purchase of a separate software package for Holladay 2 calculation. (Mahdavi, 2011)
14. Holladay 2: Recommended formula usage Srivannaboon et al. 2013
15. Holladay 2: Recommended formula usage Srivannaboon et al. 2013 (cont.)
16. References: 1. Mahdavi, S. 2011.IOLMaster 500 and Integration of the Holladay 2 Formula for IOL Calculations. Available at www.sm2strategic.com. 2. Mahdavi, S. The IOLMaster and its Role in Modern Cataract Surgery, November 2011, available at www.sm2strategic.com. 3. Srivannaboon, S. Chirapapaisan, C. et al. Accuracy of Holladay 2 Formula Using IOLMaster Parameters in the Absence of Lens Thickness Value. Graefe's Archive for Clinical and Experimental Ophthalmology. November 2013, Volume 251, Issue 11, pp 2563-2567.
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