IOL calculation 4th generation: Holladay 2

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.