The majority of patients presenting for cataract surgery have some degree of corneal astigmatism (1). In planning surgery for patients who desire greater spectacle independence, every attempt should be made to correct astigmatism to as close as possible to plano with a toric intraocular lens (IOL), on-axis incisions, and/or arcuate incisions.
However, there are a number of reasons why tolerance to astigmatism is a desirable characteristic for an IOL. First, surgeons don’t always precisely hit the target of emmetropia. Modern IOL power formulas have gotten very good: Jennings and Ball found a mean absolute error of 0.25 ± 0.17 D and 94% of eyes within ±0.5 D of target refraction using the Barrett Universal II formula in a real-world clinical setting (2). However, through surgeon error, formula shortcomings or other factors, some patients still end up with residual error.
When a patient is expecting to wear glasses anyway this may not be a big deal, but for patients who have chosen a presbyopia-correcting IOL, residual error can result in considerable dissatisfaction with the surgeon and the surgical outcome.
Short, long, or post-refractive eyes are more likely than average to have residual refractive error. And even when the result is perfect, patients may not remain plano forever. We know that the eye tends to become slightly more astigmatic with age, typically in the against-the-rule (ATR) orientation, so a younger cataract patient may drift away from plano over time. Dry eye or poor tear film quality can also induce astigmatic error in pseudophakic patients.
I have been implanting the Tecnis Odyssey full visual range (FVR) IOL in patients seeking spectacle independence with excellent results. My perception was that the lens seemed to be quite forgiving of residual astigmatism, but I wanted to objectively test the amount of astigmatism that patients with this lens could tolerate.
Topline study results
We prospectively enrolled 30 patients who had previously been bilaterally implanted with the lens. At the phoropter, we corrected the manifest refraction to plano, and then began adding astigmatism in 0.5-D increments, in ATR, with-the-rule (WTR), and oblique axes.
In the study, which was presented at the 2025 American Academy of Ophthalmology (AAO) annual meeting (3), Tecnis Odyssey patients were able to maintain visual acuity within one line of their best-corrected visual acuity even when we induced up to 1.0 D of WTR astigmatic defocus and with up to 0.5 D of oblique or ATR astigmatic defocus. Mean visual acuity with 1.0 D of astigmatic defocus was 0.10, 0.14, and 0.14 logMAR in the WTR, ATR, and oblique axes. More than 90% of the Odyssey patients achieved visual acuity of 20/40 or better with up to 1.5 D of WTR astigmatism and up to 1.0 D of ATR or oblique astigmatism, which is very impressive.
We know that with some simultaneous vision (SV) IOLs, visual quality decreases significantly and dysphotopsias may worsen with residual refractive error (4, 5). A number of advanced optical design factors contribute to high visual quality with the Tecnis Odyssey lens. Similar to other IOLs on the Tecnis platform, it has the highest available spherical aberration correction, a high Abbe number for minimal internal reflections, and chromatic aberration control. In addition, the Odyssey has a non-uniform diffractive profile with smoother, more rounded echelettes to reduce light scatter and dysphotopsia. It more evenly distributes light in order to maximize contrast sensitivity function, including in areas of out-of-focus light. Finally, it also offers violet light filtration (VLF) to block short wavelengths. Researchers have reported that VLF can reduce the incidence or intensity of halos, reduce retinal veiling luminance, and enhance contrast (6, 7).
In our study, patient satisfaction was high and 96.6% of patients said they do not need to use spectacles. In my experience, the distance vision is very good right from the start, which makes this lens a great choice for patients with otherwise healthy eyes who want full spectacle independence, especially if they are active or spend a lot of time using digital devices. I don’t implant it in eyes with retinal pathology, severe dry eye, irregular astigmatism, corneal scars, or other conditions that would typically exclude someone from consideration for an SVIOL.
Night vision symptoms
It is also important to understand the dysphotopsia profile of the IOLs we use. All presbyopia-correcting or SVIOLs involve some trade-offs in quality of vision, especially at night, in order to provide vision at all distances. With the latest generation of IOLs, these compromises have been reduced, but it is still helpful to know which dysphotopsia symptoms are most likely with different lenses.
In our study, we also evaluated how the Tecnis Odyssey IOL performed using the Assessment of IntraOcular Lens Implant Symptoms (AIOLIS) questionnaire, which was developed by an AAO task force that included surgeons, industry, FDA personnel, and survey science experts, specifically to evaluate SVIOLs (8). Most questionnaires used in the past weren’t really intended to measure pseudophakic quality of vision, so this questionnaire is a significant improvement. What I really like about the AIOLIS is that it gives patients a pictorial description of 14 visual symptoms, including glare, halo, starbursts, spiderwebs, snowballs, and crescent-shaped shadows. That way, we know that patients understand what we mean by each of those terms. The questionnaire asks how often they have experienced each symptom within the past seven days and how much they have been bothered by that symptom.
Among patients implanted with the Tecnis Odyssey IOL, we found that night glare and halo were the most common symptoms, but these were only ranked as “extremely bothersome” in 3% and 7% of cases, respectively. Starbursts and spiderwebs, which have been reported with some previous IOLs, were uncommon in our patients.
In conclusion, preliminary data from this study demonstrates that the Tecnis Odyssey IOL is tolerant of residual astigmatism and provides patients with an excellent range of vision with minimal visual disturbances.
References
- T Ferrer-Blasco et al., “Prevalence of corneal astigmatism before cataract surgery,” J Cataract Refract Surg, 35, 70 (2009).
- E Jennings, B Hall, “A retrospective study of visual outcomes when using a cloud-based surgical planning platform and the Barrett Universal II formula,” Clin Ophthalmol, 18, 2605 (2024).
- KM Rocha et al., “Optical phenomena and tolerance to simulated astigmatism of a violet light filtering diffractive full-range vision IOL,” AAO, (2025).
- E Pedrotti et al., “Comparative analysis of objective and subjective outcomes of two different intraocular lenses: Trifocal and extended range of vision,” BMJ Open Ophthalmol, 5, e000497 (2020).
- LA Rementería-Capelo et al., “Tolerance to residual refractive errors after trifocal trifocal toric intraocular lens implantation,” Eye Contact Lens, 47, 213 (2021).
- C Canovas et al., “Optical and visual performance of violet blocking intraocular lenses,” Invest Ophthalmol Vis Sci, 60, 3717 (2019).
- M van der Mooren et al., “Effect of violet light-filtering and manufacturing improvements in an extended depth-of-focus IOL,” Clin Ophthalmol, 17, 701 (2023).
- S Masket et al., “Symptoms and satisfaction levels associated with intraocular lens implants in the monofocal and premium IOL patient-reported outcome measure study,” Ophthalmology, 130, 726 (2023).
