Eyeworld

52 | EYEWORLD | JULY 2023 R EFRACTIVE Relevant disclosures Chang: Johnson & Johnson Vision Waring: Johnson & Johnson Vision Contact Chang: dchang@empireeyeandlaser.com Waring: georgewaringiv@gmail.com "When you put a chromophore in the eye, patients will look through it for the rest of their lives. If the particular chromophore is transmitting too much light, they can easily put on sunglasses, but if a chromophore blocks a percentage of useful light, the patient will never be able to recover that. Therefore, it's better to filter out what is always bad and transmit what may sometimes be good. To do this effectively, one must consider narrow wavelength bands, 10 nm segments, when looking at the filter," Dr. Chang continued. Dr. Chang said that visual performance is the most important consideration when select- ing a chromophore. He recently co-authored a laboratory study looking at the effect of a violet light filter on clinical performance of the Tecnis Symfony. 3 The study showed a 19% improve- ment in halo performance, up to 17% reduction in retinal veiling luminance (glare, halos, and starbursts), and up to 13% improvement in con- trast under challenging light conditions. This aligns with a retrospective study that he presented at the 2022 ASCRS Annual Meeting, in which he compared the clinical performance of Tecnis Symfony OptiBlue with InteliLight to colorless Tecnis Symfony. 4 He demonstrated up to 45% reduction in dyspho- topsia complaints and up to 72% reduction in postoperative dysphotopsia counseling in patients with Tecnis Symfony OptiBlue with InteliLight. Chromatic aberration can significantly degrade visual quality. The proper chromophore can potentially lessen the negative effects of chromatic aberration from a lens with low Abbe number (high chromatic aberration) by filtering out high energy, short wavelength light that may be out of focus due to the high dispersion. Nevertheless, starting with a high Abbe number material with low dispersion and low chromatic aberration is still the preferred approach. Scotopic vision requires participation of rod photoreceptors, which are sensitive to blue light. Filtering out that blue light can reduce scotopic or low light vision. The ideal chromophore would filter violet and not blue light, protecting scotopic vision while reducing dysphotopsias. When looking at retinal photoprotection, Dr. Chang said, the shorter the wavelength, the higher the energy, and the more damage it can do. In general, wavelengths in the range of 410 nm and below have increasingly greater toxicity. Ultraviolet light is 380 nm and below. "Both higher energy violet and blue light can have some potential phototoxicity effects," he said. But since blue light can impact func- tional vision, you would prefer to filter it with a pair of sunglasses. You want to make sure you're only blocking the primarily negative wavelengths in the eye. Finally, with circadian rhythm, Dr. Chang said there are the intrinsically photosenstive retinal ganglion cells, which have sensitivity in the blue light spectrum. When you wake up in the morning to a lot of blue light, this increases melanopsin production and inhibits melatonin production. The idea is to reduce blue light exposure as the day goes on to help maintain circadian rhythm. Blocking blue light may thus interfere with circadian rhythm function. Looking at the absorption spectrum, the AcrySof IOL (Alcon) blue light-filtering chromo- phore filters up to a third of blue light wave- lengths, and because it has a broad spectrum range, filtration depends on the IOL power, so it's not consistent. The Johnson & Johnson Vision violet light-filtering chromophore has a steep peak. More importantly, you're keeping blue and filtering violet, Dr. Chang said. The Alcon chromophore filters out blue light, which potentially could affect scotopic vision and cir- cadian rhythm, but it doesn't filter out all of the high energy violet light, with up to 25% of the 410 nm violet still being transmitted vs. 0% for the Johnson & Johnson Vision chromophore. In a presentation that looked at the theo- retical comparative impact of a violet vs. blue light filter, Dr. Chang shared data showing the Johnson & Johnson Vision violet light filter hav- ing less decrease in scotopic vision, less impact on circadian rhythm, and the same amount of macular photoprotection. 5 Dr. Waring said he has largely moved to violet filtration for presbyopia-correcting IOLs, but he added that InteliLight is reserved for diffractive presbyopia-correcting IOLs. Johnson & Johnson Vision is currently the only manu- facturer to offer this, and it is not offered in a monofocal or monofocal toric. "More patients are seeking presbyopia correction, but those who are not a candidate would still benefit from violet filtration in the monofocal and monofocal toric." continued from page 51

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