Toric IOL implantation
During the Ophthalmic Premier League session on Monday, presenters shared a variety of video presentations on cataract complications.
Kamran Riaz, MD, discussed his case of toric IOL misadventures. The case featured a 28-year-old male. Dr. Riaz operated first on the patient’s amblyopic left eye and had a good outcome. Then he moved on to the right eye and put in a toric at 80 degrees. The patient did well for 2 weeks, but a month later, he bled again and the IOP was up to 40. The patient was sent to a glaucoma specialist, who put in a glaucoma tube. However, during this, the glaucoma surgeon accidentally cut a suture, the IOL dislocated, and a bleb was put at 80 degrees, which was the steep meridian.
Dr. Riaz then had to explant the IOL and do a Yamane technique IOL and LRI.
He shared several conclusions and lessons from his case, notably that discussion with colleagues regarding surgical landmarks is critical. Complications from one technique can be managed with alternative scleral fixation techniques, he said, and modern anterior segment surgeons need to have multiple tools in their toolbox.
Editors’ note: Dr. Riaz has no relevant financial interests.
Primary angle closure disease
In a glaucoma session Monday morning, Benjamin Xu, MD, PhD, presented on new imaging techniques and treatment choices for narrow angles. He noted that the basic stages of angle closure remain the same: primary angle closure suspect, primary angle closure, and primary angle closure glaucoma (PACG). He said the visual morbidity of PACG is well known, and even in the U.S., blindness is common.
One clinical need in this area, Dr. Xu said, is for a convenient and precise tool to identify high-risk eyes. Gonioscopy has been the longstanding gold standard for evaluating the angle, but we also know it’s underutilized, he said.
Anterior segment OCT (AS-OCT) is an option that can provide high-resolution images and perform quantitative analysis of these images. It can also obtain biometric measurements. One issue, however, is that busy clinicians don’t have time to manually analyze AS-OCT images, Dr. Xu said, adding that it does take time and expertise to identify the scleral spur. This is where AI can become a useful tool.
Another clinical need in the PACG arena, Dr. Xu said, is clearer guidance on managing severe PACG. Phacogoniotomy can be viable in severe PACG eyes.
Editors’ note: Dr. Xu has financial interests with Heidelberg.
Premium lenses and glaucoma
Christine Larsen, MD, presented on the premium lenses available and what’s new, including considerations for patients with glaucoma.
There are a multitude of options to offer our patients, she said, but glaucoma requires us to consider a range of anatomical considerations, like pupil size, zonular stability, axial length and effective lens position, narrow angles, and the possibility of future filtering surgery.
The presence of pseudoexfoliation is a specific challenge, Dr. Larsen said, adding that using premium lenses in these patients depends on a number of things, including stability of the disease, pupil dilation, and zonular stability.
Discussing IOLs in pseudoexfoliation, Dr. Larsen said there is data with toric and multifocal IOLs, at 24 months, that shows a group of patients with pseudoexfoliation having low prediction error, stable refractive outcomes, and excellent visual function. However, there is a refractive surprise risk in pseudoexfoliation. These eyes might also have a tendency toward a hyperopic shift. Dr. Larsen also noted that the Barrett Universal II formula may provide the greatest accuracy in these patients.
Another common and significant concern in glaucoma patients is the use of topical therapy and its effects on the ocular surface.
One of the primary concerns of premium IOLs is the impact they can have on contrast sensitivity. Loss of retinal ganglion cells and RNFL thickness corresponds to a loss of contrast sensitivity in early disease, Dr. Larsen said. Reduced contrast sensitivity is seen in most presbyopia-correcting IOLs related to the splitting of the amount of light that reaches the retina for distance vision. Traditional high-add multifocal IOLs decrease distance contrast by almost 20%. Dr. Larsen added that the defocus created with monovision can also decrease contrast sensitivity.
In terms of multifocal IOLs, Dr. Larsen said the data on their use in glaucomatous eyes is minimal. An early study demonstrated a benefit of multifocal IOL implantation in eyes with previous disease and found that potential visual disturbances were not as disruptive as previously thought. Multifocal IOLs are generally associated with greater spectacle independence but require cautious selection due to their light-splitting nature and potential impact on already compromised visual function. Multifocal IOLs are generally contraindicated in patients with moderate to severe glaucoma or those with significant visual field loss, particularly central defects, Dr. Larsen said. Additionally, multifocal IOLs are associated with increased risk of glare and halos, which may be more debilitating and noticeable for glaucoma patients.
EDOF IOLs are another option to provide an extended range of vision. These offer improved intermediate vision with significantly less optical phenomena and less impact on contrast sensitivity compared to diffractive multifocals. Dr. Larsen discussed both the Vivity (Alcon) and Symfony (Johnson & Johnson Vision) lenses.
Finally, Dr. Larsen mentioned monofocal options (both standard and toric), which she said remain the gold standard for these patients. Monofocal IOLs do not split light and are widely accepted for use in moderate to severe disease. There are also no concerns about the induction of photic phenomena. The Light Adjustable Lens (LAL, RxSight) can also be an outstanding tool in glaucoma, Dr. Larsen said.
She shared several other considerations to keep in mind. One was the impact of some premium technology on testing. Diffractive technology can cause wavy horizontal artifacts on OCT. Pay attention to foveal sensitivity on the visual field, Dr. Larsen said, adding that you should also be on the alert for a steroid response (consider tapering the steroids more quickly). Her most important pearl was to have a conversation with every glaucoma patient about the options.
Editors’ note: Dr. Larsen has financial interests with Alcon, Glaukos, and Iantrek.
Perfect prediction
During the cataract crises session on Sunday afternoon, Graham Barrett, MD, gave the Kelman Lecture on “Perfect Prediction … Are We There Yet?” He discussed his interest in prediction and formulae to help achieve accurate refractive outcomes.
He discussed some of the history of these prediction formulae, noting that the first was introduced in 1967 by Fyodorov. Each generation, the accuracy of prediction improves, Dr. Barrett said. Today, we can predict outcomes and expect good outcomes and accurate results.
Dr. Barrett noted that some formulae are based on optics and some on artificial intelligence. In the last 5 years, there has been a proliferation of different formulae. Dr. Barrett also noted a recent publication from 2023, which was a meta-analysis of all the latest formulae, particularly those based on optics and artificial intelligence.
Looking at artificial intelligence as a pathway, Dr. Barrett said these formulae can use data like axial length, Ks, and ACD and present it to the artificial intelligence to train the data. This uses pattern recognition and develops a formula. It’s called a black box because even the data scientists don’t understand how the process of machine learning works. Dr. Barrett said that he and others benchmark to try to see the most likely pathway to get the perfect prediction.
Looking at artificial analysis versus a theoretical model, Dr. Barrett said there are differences in emphasis among optical formulae. A theoretical formula is based on things like ELP prediction, biometry, new parameters, etc. Meanwhile, AI is essentially a data processing process looking at reducing noise in datasets. It’s a big data exercise, he said. So, there is a different emphasis, but there is overlap. Any formula still requires some data-driven optimization.
Looking at his own formula work, Dr. Barrett said that unlike with artificial intelligence, he knows every detail about his formula, every algorithm, and line of code. This is powerful in being able to try to optimize and improve, he said, adding that his interest in formulae began back in 1983. What’s unique about each formula is the way the author chooses to try to estimate the final position of the lens and why that position will vary with axial length. Dr. Barrett went on to discuss more about his formulae, their evolution, how they can be used, and parameters.
Editors’ note: Dr. Barrett has financial interests with Alcon, Haag-Streit, Nidek, Oculus, Rayner, Topcon, and Zeiss.
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