Published in Interventional Mindset

How the LRI Calculator Can Improve Refractive Outcomes

Jonathan D. Solomon, MD

Jonathan D. Solomon, MD

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In this video from Interventional Mindset, Jonathan Solomon, MD, discusses why he's adopted the LRI Calculator and how it's improving his refractive outcomes.

Over the last decade and a half, clinicians have used a range of nomograms—DONO (Donnenfeld nomogram),1 NOMO (Nichamin Age and Pachymetry Adjusted nomogram),2 and others—to optimize predictability with both manual and laser-assisted correction.
However, in the summer of 2020, refractive surgeons gained an impressive new tool with The Wörtz-Gupta™ LRI Calculator, which I consider one of the most valuable innovations for lens-based refractive surgery in recent years.

Interventional Mindset is an educational series that gives eye physicians the needed knowledge, edge, and confidence in mastering new technology to grow their practices and provide the highest level of patient care. Our focus is to reduce frustrations associated with adopting new technology by building confidence in your skills to drive transformation.

Browse through our videos on a variety of topics within cataract and refractive surgery, glaucoma, and ocular surface disease to learn practical insights into adopting a variety of new surgical techniques and technology.

The Wörtz-Gupta LRI calculator

First introduced by Gary Wörtz, MD, and Preeya K. Gupta, MD, in a paper they co-authored, “Outcomes of Femtosecond Laser Arcuate Incisions in the Treatment of Low Corneal Astigmatism,” the Wörtz-Gupta limbal relaxing incisions (LRI) calculator provides a formula to attain accurate, individualized measurements to be used in femtosecond laser-assisted arcuate incisions for the treatment of astigmatism.3
With 224 patients as the study population, the breakdown was an almost even split between the control (n=100) and treatment (n=124) groups based on the average pre-operative cylinder measurements.
The surgeons set out to answer two questions:
  • Does uncorrected low corneal astigmatism (between 0.25 to 1D [diopter]) impact uncorrected visual acuity (UCVA) outcomes after cataract surgery?
  • Can a femtosecond laser be used to effectively treat low levels of astigmatism?
The answer to both was a resounding “yes.” The astigmatic patients treated with femtosecond laser arcuate incisions were 1.8 times more likely to have 20/20 UCVA after cataract surgery. With regard to achieving 20/25 UCVA or better, the increase was 3.5 times. In addition, within the laser arcuate treatment group, there was a statistically significant increase post-operatively in patients with ≤0.5D of astigmatism, which accounted for 89% of those patients.3

My experience with the Wörtz-Gupta formula

My surgical experience echoes their findings. Within our practice, I am not only a clinician and surgeon, but also serve as research director and biometrist. And, for me, femtosecond lasers have done the best job to date of simplifying the process of placing arcuate incisions using one’s individualized nomogram.
The Wörtz-Gupta nomogram employs a 9mm optical zone with 80% depth on the steep axis, with all primary wound incisions being performed temporally on the 180-degree meridian, approximately. After entering the patient information, the LRI calculator provides a personalized diagram to be used during the planning and procedure.
Our practice implemented the Wörtz-Gupta LRI calculator with stellar results. We have discovered that for 1.2 to 1.25D of astigmatism (both with and against the rule), our ability to achieve 20/20 UCVA post-cataract surgery has increased by nearly two times. Also, in these patients, as opposed to those whose astigmatism is not being corrected at the time of surgery, we are far more likely to achieve less than 0.25D of cylinder. With the traditional gold-standard benchmark being 0.5D or less, we are thrilled to see this twofold improvement.
I would be remiss not to mention the convenience factor. Having the LRI calculator online at our fingertips (www.LRIcalc.com) has made calculating astigmatism correction incredibly easy. It can even be accessed in the operating room at the time of surgery and applied immediately.

In conclusion

Having a free, online, evidence-based nomogram that clinicians can seamlessly implement into their practice is revolutionary for refractive surgeons. After entering the required data, the formula generates the precise and individualized measurements to help you potentially achieve premium visual outcomes for low-level astigmatism patients.
If you have not utilized the Wörtz-Gupta LRI calculator, I would encourage you to take advantage of this groundbreaking software.
Disclaimer: The Wörtz-Gupta™ Formula (patent pending) femtosecond laser arcuate incision calculator is meant to serve as an adjunct tool to assist physicians in the correction of astigmatism in conjunction with the intraocular lens (IOL) placement. The information contained herein is derived from the work and nomogram(s) of Gary Wörtz, MD, and Preeya K. Gupta, MD. The medical opinions and views expressed in the Calculator are those of Drs. Wörtz and Gupta and not those of any manufacturer of femtosecond lasers.
  1. Stein JM, Donnenfeld ED. Pearls for LRIs with Presbyopic IOLs. https://www.ophthalmologymanagement.com/issues/2008/april-2008/pearls-for-lris-with-presbyopic-iols. Published April 1, 2008. Accessed June 7, 2023.
  2. Nichamin LD. Nomogram for limbal relaxing incisions. J Cataract Refract Surg. 2006;32(9):1408. doi:10.1016/j.jcrs.2006.03.046
  3. Wörtz G, Gupta PK, Goernert P, et al. Outcomes of Femtosecond Laser Arcuate Incisions in the Treatment of Low Corneal Astigmatism. Clin Ophthalmol. 2020;14:2229-2236. Published 2020 Aug 7. doi:10.2147/OPTH.S264370
Jonathan D. Solomon, MD
About Jonathan D. Solomon, MD

Dr. Jonathan Solomon is a board-certified ophthalmologist specializing in laser cataract and refractive surgery. He is well known for his activity in the ophthalmic academic community, as well as for his spirit and compassion, which extend beyond the surgical theater.

Dr. Solomon has been acknowledged by GQ Magazine in their “Men of the Year” issue, recognized nationally as one of the “Top Doctors in America” by his peers, and listed as one of Baltimore-Washington’s Super Doctors for 2013.

He works closely with the leading manufacturers of precision surgical equipment, including instruments and intraocular lens implants, and engages in a variety of studies. Some noteworthy studies include the FDA evaluation of accelerated corneal collagen cross-linking for the treatment of keratoconus, corneal ectasia, and the Visian Toric Phakic Intraocular Lens.

Solomon Eye Physicians & Surgeons is also proud to participate in the refinement of LENSAR LASER's STREAMLINE IV/Ally for laser refractive cataract surgery, which allows us to offer patients a more precise, custom procedure as unique to our practice as your eyes are to you.

As the Chief of Ophthalmology at the University of Maryland, Capital Regional Surgery Center and co-founder of the Bowie Vision Institute for Applied Studies, Dr. Solomon continues to educate and train the next generation of refractive and corneal reconstructive surgeons and a fellowship preceptor for the UMD School of Medicine, Department of Ophthalmology & Visual Sciences.

Dr. Solomon proudly offers and pioneered the application of the Callisto Guidance, which allows for Virtually Augmented-assisted feedback in the operating theatre. Dr. Solomon also uses 3D Surgical Guidance, the only one of its kind in the DMV, which ensures precise refractive outcomes for all of the FDA-approved presbyopia-correcting intraocular lenses (IOL): PanOptix, Vivity, Eyhance, Synergy, Tecnis Multifocal, and the RxSight Light Adjustable Lens.

Additionally, to correct astigmatism, the implantation of a wide variety of toric lenses is available to his patients. For Dr. Solomon's highly myopic patients, those who do not qualify for LASIK or PRK, he is a key opinion leader for the implantation of Visian ICLs, which are surgically implanted contact lenses that can give refractive correction and spectacle/contact lens freedom.

Dr. Solomon is an active contributor to the ophthalmic community as a member and leader in multiple professional societies and other organizations.

These include:

  • Medical director of Dimensions Surgery Center
  • Co-founder of the Bowie Vision Institute
  • Fellow of the American Academy of Ophthalmology
  • Fellow of the American Society of Cataract and Refractive Surgery
  • Fellow of the International Society of Refractive Surgeons
  • Executive board member of the Maryland Society of Eye Physicians and Surgeons
  • Official Terps LASIK surgeon at the University of Maryland
  • Founding member of the American-European Congress of Ophthalmic Surgeons
  • Accreditation Board member of the Cornea Society
  • Active consultant to the FDA's Ophthalmic Device Panel
  • Former Clinical Instructor at the Wilmer Eye Institute at Johns Hopkins University

Hospital privileges:

  • Reston Hospital
  • Northern Virginia Eye Surgery Center
  • Fairfax Surgical Center
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