August 25, 2015
4 min read

Which device do surgeons prefer for optical biometry?

David A. Goldman, MD; and P. Dee Stephenson, MD, FACS, ABES, FSEE, weigh the pros and cons of the Lenstar and IOLMaster.

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Welcome to CEDARS-ASPENS Debates, a monthly feature in Ocular Surgery News.

CEDARS (Cornea, External Disease, and Refractive Surgery Society) and ASPENS (American Society of Progressive Enterprising Surgeons) is a joint society of cornea, cataract and refractive surgery specialists, here to discuss some of the latest hot topics in ophthalmology.

As surgical techniques and technology continue to improve, cataract surgeons are obtaining unprecedented success. This has led to increased patient demands, which in turn has led to surgeons trying to find every avenue possible to achieve success. While most of the attention has been paid to IOL selection, phaco and femto technology, and imaging, perhaps the most important aspect is the preoperative biometry. This month, David A. Goldman, MD, and P. Dee Stephenson, MD, FACS, ABES, FSEE, discuss the two most common devices currently being used, the Lenstar and the IOLMaster. We hope you enjoy the discussion.

Kenneth A. Beckman, MD, FACS

Lenstar is best for optical biometry

David A. Goldman

Although traditional A-scan and immersion technology can be quite accurate, over time ophthalmologists have moved toward optical biometry systems. They offer not only non-contact measurements of axial length and corneal curvature, but also provide additional data allowing advanced IOL calculations to be performed. For most of my career, the IOLMaster (Carl Zeiss Meditec) has been the reigning champion. However, when it came time to purchase a device for my practice 2.5 years ago, there was no question I wanted the Lenstar (Haag-Streit).

There were multiple reasons for this choice. To begin, my history with Zeiss equipment was frustrating. Although most devices Zeiss makes are excellent, the constant recurrent charges for upgrades are brutal. Case in point is the Atlas topographer. I purchased the device at the end of 2012, and at that time the device was running Windows XP (for those Mac users, I will explain that even in 2012, XP was seriously outdated). The machine cost approximately $12,000. Recently I received a notice that I could upgrade the device to Windows 7, which would include a new DVD drive (not sure why this is necessary because it already has a DVD drive) for about $3,000. Again, for the Mac users out there, Windows 7 is already outdated, and Microsoft is giving away Windows 10 for free.

With the Lenstar, there was one purchase in 2012. Since then, I have received multiple upgrades to improve algorithms for measurements in dense cataracts and IOL formulas at absolutely no cost.

Besides service, I believe the technology of the Lenstar is simply better. For keratometry, 32 points are measured as opposed to six on the IOLMaster. I have been so impressed with keratometry that I do not perform any manual keratometry readings and routinely hit 20/20 uncorrected outcomes. In cases of toric IOLs, I find myself trusting the axis and magnitude of the astigmatism measurement of my Lenstar over my topographer in most cases. Furthermore, the Lenstar optically measures lens thickness, giving it a clear advantage for the newer-generation multivariable formulas. Finally, the anterior chamber depth measurement on the Lenstar is acquired using the superluminescent diode, as opposed to the slit lamp illumination from the side that the IOLMaster uses.


From a hardware standpoint, the Lenstar also has advantages. Specifically, the PC is separate from the device, so in the case of hard drive or other PC crash, a different computer can be used to run the device. This gave me more comfort to defer a service contract when the warranty ran out.

From a utility standpoint, the machine is excellent. The footprint of the machine makes it easy to use in patients with deep- or shallow-set eyes or wheelchair-bound patients. My lead technician, who has used both IOLMaster and Lenstar, finds the Lenstar easier to use, and again, refractive outcomes have been nothing short of superlative.

In summary, I chose the Lenstar over the IOLMaster for my practice because I believe it had better technology, service, longevity and ease of use. I would highly recommend it to anyone looking to purchase an optical biometry device.

Disclosure: Goldman reports no relevant financial disclosures.

IOLMaster remains gold standard

The Zeiss IOLMaster 500 is the gold standard in optical biometry. I trust in the accuracy, repeatability and consistency of measurements. That has long been proven.

P. Dee Stephenson

When I think of the success of biometry in my office and how much I depend on it, I first have to think of the total ease of use of distance-independent measurements and an up to four times faster reading compared with other optical devices. The test time can be less than 1 minute, which minimizes “chin time” and “chair time,” thereby increasing the flow in my office. Today there are so many tests done by my tech that I am spoiled because she has been doing all of my preop testing for the last 15 years. So anything that is helpful to her to decrease time and aggravation is helpful to my patients and me.

The composite signal analysis does a great job of penetrating dense cataracts and pretty much eliminates the need to review, manipulate or delete individual readings, which is great for you as the surgeon when you are not taking the axial length measurements yourself.

Both the axial length readings and the keratometry, which uses telecentric optics and is less affected by vertex distance, provide a measurement workflow that is easy and consistent, even on patients who are typically difficult to measure, such as elderly patients with tremors, fixation problems or Parkinson’s — patients who the Lenstar has a hard time capturing.

I use Haigis-L for all my post-LASIK/PRK patients. It is a great formula for when you do not have any refractive history, and with my large post-refractive practice, this is a must. The Holladay 2 formula is integrated as well, the gold standard in optical biometry to help you improve your refractive outcomes. Finally, the User Group for Laser Interference Biometry website database has hundreds of IOLs included with optimized lens constants to use as a starting point for further on-board optimization of your personalized lens constants. This is unique in the ophthalmic industry. Any IOL calculation is only as reliable as the lens constant it is based on.

Thinking about the future, soon to be released is the IOLMaster 700. Zeiss revolutionized cataract pre-assessment with the first optical biometer, and it is poised to do the same again with the first swept-source OCT-based biometry device, the IOLMaster 700. Without a doubt, I am a believer in this technology. I have based my successful outcomes on this, and it has proven to me over and over again how invaluable it has become. Zeiss has always been on the forefront of technology, so I am poised for its next act.

Disclosure: Stephenson reports no relevant financial disclosures.