Source of Complaints Often Elusive for Multifocal IOLs

Despite the wide array of sophisticated diagnostic tools now available to clinicians, it is not always possible to predict or determine the source of patient dissatisfaction after implantation of a premium intraocular lens, according to Giacomo Savini MD.

“There are two main issues to consider: preoperative selection of candidates for multifocal IOLs and postoperative assessment of patients complaining of visual disturbances,” he said. “In both cases, we have a lot of instruments available to us but many times we do not have clear answers to assuage our doubts.”

Several parameters need to be considered in the preoperative selection of candidates to achieve successful outcomes, Dr Savini noted. Corneal topography helps exclude cases with irregular patterns—which standard keratometry cannot detect—and may indicate forme fruste keratoconus or decentred ablation after myopic PRK or LASIK.

Although corneal aberrometry is mandatory before implanting a multifocal IOL, no clear evidence-based guidelines are available to determine the cut-off point for excluding certain cases.

The same also holds true for pupil diameter, said Dr Savini.

“We tend to implant multifocal IOLs when the pupillometry shows a photopic diameter of more than 2.5 mm and a scotopic diameter of less than 6.5 mm or 6.0 mm. However, again there are no evidence-based recommendations. We need to better characterise the relationship between actual pupil size during day and night and the IOL performance.”

BEWARE OF OSD

Before proceeding with any surgery, Dr Savini advised treating ocular surface problems and dry eye disease (DED).

“No patient with severe dry eye should be implanted with these lenses, and we need to manage moderate dry eye using topical therapy and/or punctum plugs. Likewise, we should exclude macular problems, so no epiretinal membranes and no staphylomas for diffractive multifocal IOLs,” he said.

Dr Savini said it was probably also prudent to avoid implanting multifocal IOLs in cases where the IOL calculation is very difficult.

“Eyes that fall outside the ‘normal’ range of measurements require special attention. Long eyes are best avoided, and caution is required with short eyes, which carry a higher risk of refractive surprise,” he said.

Although there are many diagnostic tools to help screen the best candidates for multifocal lenses, no single device captures all the essential information needed to make a full assessment.

“What we really require is a comprehensive, evidence-based artificial intelligence-supported tool able to predict the risk of postoperative visual complaints, the risk of refractive surprises, and the visual performance for distance, intermediate, and near vision,” Dr Savini observed. “The tool should be based on prospective studies correlating the preoperative data from the tear film to the macula to the postoperative visual function.”

Even after rigorous patient selection, uneventful surgery, and ostensibly good visual outcomes, some patients will still complain of hazy or poor quality of vision after surgery, Dr Savini said.

While some of these are straightforward to diagnose—such as residual refractive error, dry eye, or macular pathologies—others are less easy to identify the source.

“The reality is that sometimes everything looks perfect with the technology that we have available, and the patient is still unhappy. Neuroadaptation is clearly a factor in many cases, but the complaints do not always resolve in time. It would be nice in the future to be able to objectively quantify these problems and follow up on the visual complaints,” he concluded.

Dr Savini presented at the 40th Congress of the ESCRS in Milan.

Giacomo Savini MD is an ophthalmologist in private practice in Bologna, Italy, and a researcher at the GB Bietti Foundation – IRCCS in Rome, Italy. giacomo.savini@startmail.com