She had single-eye (right) cataract surgery with PanOptix at another clinic 11 days earlier, but the halos were far worse than she had imagined and were interfering with daily life, so she first visited us in May 2023 to consult about an exchange for Clareon Vivity.
The operated eye had been operated on cleanly without any particular problem. Uncorrected vision was 1.0p distance / 0.8p near; machine-measured objective refraction was a spherical equivalent of −0.625 D with residual astigmatism of 0.75 D with-the-rule, and subjective spherical equivalent was −0.50 D with low residual astigmatism of 0.50 D, so there was no large refractive error.
Of course, being 0.50 D myopic compared with 0.0 D might make halos and glare slightly larger, but in our clinical experience this is not a refractive error that causes problems, so the symptoms seemed to be caused by PanOptix's diffraction grating rather than refractive error. Exchanging for Vivity might well resolve photic phenomena such as halos and glare, but 11 days after surgery was still too early to judge, and the photic phenomena might ease, so we asked her to wait at least one month after surgery and return if she still wished to exchange the lens.
At one month after surgery she returned with preoperative data and a referral letter from her previous doctor, saying that she still felt strong halos and glare even during the day, to the point of nausea, and wished to have the lens exchanged. Refraction had not changed, but uncorrected vision had improved to 1.0 distance / 1.2 near. We said it might be a waste, when her vision was so good, to exchange PanOptix, with a near add of +2.5 D at the corneal plane, for Vivity at about +1.5 D, but her symptoms were bad enough to make her unwell, and she strongly wished for the exchange. Since the surgery had been done cleanly, we also recommended having the exchange at the previous clinic, but as of June 2023 Vivity had not yet been released, and she was worried that the risk of complications from an exchange would rise while waiting for its general release, so she wished to have surgery at our clinic, and we scheduled the exchange at short notice.
Corneal astigmatism in the right eye, anterior and posterior surfaces combined, was 1.01 D with-the-rule, and a non-toric PanOptix had been used, but total astigmatism on objective refraction was 0.75 D, so we predicted that even Vivity without a toric version would very likely give equivalent vision. Also, PanOptix and Vivity differ only in whether the base monofocal Clareon lens has a diffraction grating or a wavefront-shaping zone, so although their A-constants differ by 0.1, the tendency of power deviation should be almost the same (= same lens shape, so the same postoperative lens position, ELP). She had originally planned surgery on both eyes, but because of the strong photic phenomena in the right eye, surgery on the fellow left eye had been postponed. The left eye's total corneal astigmatism was also with-the-rule but 1.47 D, so a toric lens seemed essential for a multifocal lens, and we told her that, for now, we could not recommend Vivity for the left eye. She also said that the left eye was dominant and that, when a toric Vivity became available, she wanted to set the left eye exactly for distance, so she wished for the non-dominant right eye to be set slightly toward near.
The right eye's objective refraction with the current PanOptix was −0.625 D, slightly toward near, so we predicted that a Vivity of the same power as the current PanOptix would give a target slightly toward near, as she wished. To be safe, we also prepared Vivity lenses one step above and below, and decided to choose the power taking into account the results of the ORA system, an intraoperative wavefront aberrometer.
On preoperative evaluation, the anterior capsulotomy (CCC) was sufficiently large, and near 7 o'clock (blue arrow at lower left) there was an area where the lens was not covered by the CCC, so we expected to be able to separate the capsular bag from the lens relatively easily from there. Incidentally, creating the CCC so that it properly covers the whole circumference of the intraocular lens (complete coverage) and fixing the lens that way is important for stability of lens position and refraction.
Astigmatism is affected by conditions other than the cornea, but since corneal astigmatism had not been a problem even with the non-toric PanOptix, we thought that faithfully reproducing the current state would make reproducible results more likely, and, also to reduce with-the-rule astigmatism, we made the exchange incision superiorly at the same site as the original surgery. In the exchange itself, we were able to separate the lens optic from the easy-access area described above, just as we had pictured. But, perhaps because it was an Alcon lens, the haptic tips had already adhered to the capsular bag, so we separated them very gently so as not to stress the capsule, and removed the lens in pieces so as not to stress the wound. We then measured with the ORA system and decided the lens power. In inserting and fixing the lens, again to avoid changing the astigmatic conditions as far as possible, we tried to insert and fix the Vivity in exactly the same position, haptics included, as the PanOptix had been (see figure below). For reproducibility we considered deliberately leaving it off-center relative to the CCC, but in the end we gave priority to stability and refixed it centrally with complete coverage (blue arrow at lower right).
After the exchange, objective refraction was −0.625 D with 1.00 D of with-the-rule residual astigmatism; subjective spherical equivalent was −0.25 with 0.75 D of residual astigmatism; and uncorrected vision was 1.0 distance / 1.0p near.
There was no refractive error and uncorrected vision was as expected. She was pleased that the photic phenomena were gone, daily life had improved and she felt well again, but one complaint remained: "Shaky blur bothers me, and near is harder to see than I expected."
Before the exchange, she had not been bothered by blur with the non-toric PanOptix. I agonized over whether, because the 7 o'clock part of the lens was not covered by the CCC, a slight tilt of the lens might have produced coma that happened to cancel corneal coma and reduce total astigmatism, so that deliberately fixing it off-center, uncovered by the CCC, would have been better; but the OPD-Scan III detected no such difference. Her mild astigmatism was also just right for LRI (limbal relaxing incisions), so we proposed it as a way to improve the blur even a little, but she did not wish to have it.
She seemed to attribute the "blur" to increased astigmatism, but to examine the cause we added spherical power only, without correcting astigmatism, and the "blur" lessened, so the change from PanOptix (+3.25 D) to Vivity (about +2.0 D), with its smaller near add, also seemed to be a cause. Vivity is often compared with TECNIS Symfony because both are EDOF lenses with extended depth of focus, but from my experience so far, Vivity seems, if anything, poor at tolerating astigmatism, unlike Symfony. Given that she felt no "blur" with PanOptix, the wavefront-shaping Vivity may, because of its structural differences, be more affected by astigmatism than diffractive lenses, and I feel care is needed in judging candidacy.
This case confirmed that, as expected, the wavefront-shaping Clareon Vivity can be used as an alternative lens to resolve photic phenomena such as halos and glare from diffractive lenses, but it also suggested that its tolerance to astigmatism may be somewhat weak (or that the diffractive PanOptix is tolerant of astigmatism?).
Recently, photic phenomena with diffractive lenses have been seen as a problem, and Johnson & Johnson has announced TECNIS PureSee, a refractive extended depth of focus (EDOF) lens. On the other hand, diffractive lenses have the advantage, through design refinements, of being less affected by pupil size, and TECNIS Odyssey, aimed at reducing the photic phenomena of TECNIS Synergy, is also reportedly scheduled for release.
Depth of focus and photic phenomena tend to conflict: with current technology, the more a lens lets you see from distance to near, the stronger the halos, glare and starbursts. Patients are thus forced into a so-called trade-off between range of vision and sharpness, so we recommend organizing your own priorities for vision clearly before choosing a lens.
2024.01.17