Accurately marking the steep axis intraoperatively is essential for patient satisfaction postoperatively. Astigmatism is an epidemic of great proportion. As per Warren E. Hill, MD, we leave about 1,386,254.5 diopters uncorrected that only accounts for the midrange of astigmatism and only regular astigmatism that we have not embraced.
There are many reasons people give to not correct astigmatism (e.g., inconsistent outcomes, too time consuming, etc.), but a very common reason is marking the steep axis for astigmatism management. It has become an art and is well worth learning a good technique that you can perfect, so you can offer your patients this technology. This is because misalignment causes 3.3% loss of correction with every 1° misalignment and/or cyclotorsion, creating blurred vision due to residual astigmatism.
Marking techniques have come a long way from an ink mark that can spread over 10° or disappear with irrigation, to a scleral vessel identification marker that can disappear with chemosis or haemorrhage. (See “Wanted: Pristine Ocular Surface,” sidebar)
Wanted: Pristine Ocular Surface
Of great importance are comorbidities like dry eye and meibomian gland dysfunction and usage of glaucoma drops. The ocular surface needs to be pristine before you ever get to the operating room, and preop testing needs to be consistent and repeatable. All patients a pre-treated with lid hygiene and preservative-free artificial tears, and tear evaluation is done using tear break-up time and tear check, along with the tear analysis. When results are repeatable, then the cornea pristine and ready for surgery. Dry eye can cause false astigmatism.
Making my mark
For almost 16 years, I have not marked a single patient preoperatively because I use the ORA System intraoperative aberrometer, from Alcon, along with the LENSAR ALLY System, with IntelliAxis (LENSAR), which allows my preop information to be blue toothed over from my Cassini (Cassini Technologies).
The LENSAR IntelliAxis shows two 5° corneal marks 180° apart at the steep cylinder axis from upright preop infrared iris imaging from the Cassini, all of the Oculus Pentacam devices, the OPD-Scan III Wavefront Aberrometer (Marco), the Aladdin (Topcon), or the IOL Master 700 (Zeiss), and it adjusts for cyclotorsion.
Additionally, the device marks biomechanically stable and permanent landmarks on the capsule that enable precise identification of the steep axis relative to toric IOL orientation, both intra- and postoperatively.
Most recently, I have added Cassini Connect OR, which allows me to have 3 toric axis, one overlay, and one capsular marking and intraoperative aberrometry. All 3 account for cyclotorsion, and the ORA takes an aphakic reading that measures the magnitude and axis of astigmatism, as well as the posterior cornea. All my data goes into a data bank, and I look at my results and modify when necessary.
Perfect Your Technique
If you don’t follow your outcomes, you don’t know where you start. The better your outcomes, the better you can take care of your patient’s astigmatism, make them happy, and increase your proficiency. There are nuances to all technology. Learn these nuances, and you can perfect your technique and create happy patients. CP
