Intraocular lenses: the Palazzo Manzoni study in the American Journal of Ophthalmology
29.10.2026
On 29 October 2026 the American Journal of Ophthalmology, one of the most respected ophthalmology journals in the world, published a multicentre study that began in Brescia: the Italian patients were operated on and measured in our theatres. The first author is Dr. Andrea Russo, head of Ophthalmology at Palazzo Manzoni. The article, Constructing an Objective Defocus Curve from Pyramidal Wavefront Aberrometry, is open access.
What the defocus curve is
Anyone facing cataract surgery with a multifocal or extended-depth-of-focus intraocular lens wants to know how well they will see in the distance, at the computer and up close. The answer lies in the defocus curve: a chart showing how many lines of the eye chart can be read at each distance. It is the most complete way to judge a premium lens, but until now it could only be obtained subjectively, with 10-15 minutes of reading through a sequence of trial lenses, a result that depends on the patient’s cooperation and on the examiner’s experience.
The study and its results
The research group followed 98 eyes of 63 patients implanted with the RayOne Galaxy lens, a refractive spiral lens, in three centres: Brescia, Bristol and Genoa. Every eye was examined with the Osiris pyramidal aberrometer, made by CSO in Florence, which captures in a single acquisition how the eye bends light. From that measurement an algorithm simulated the blur at each distance and translated it into lines of the eye chart, building an objective defocus curve without asking anything of the patient. The method was then checked on an external cohort of 19 eyes operated on in a fourth centre, in Bologna, with other extended-depth-of-focus lenses.
The result: the objective and the subjective curves differ on average by less than one line of the eye chart (root mean square error of 0.095 logMAR in the test group and 0.092 in the external cohort, with a systematic difference below 0.02 logMAR). The depth of focus estimated by the instrument matched the one measured by the patient within 0.1-0.15 diopters. With the lens studied, 88.8% of eyes reached 20/20 at distance.
Did you know?
The pyramidal aberrometer uses a four-faced prism to split the light leaving the eye into four images of the pupil: by comparing them, the instrument reconstructs point by point how the eye distorts the wavefront, with a much higher resolution than traditional sensors. The same measurement also yields the image the eye forms on the retina, from which the objective defocus curve is built.
Source: Russo A et al., American Journal of Ophthalmology 2026
The role of Palazzo Manzoni
The Italian surgeries and measurements took place in the Ophthalmology department at Via dei Mille 14, with the same Osiris aberrometer we use every day for pre-operative diagnostics. Taking part in the research, together with Dr. Russo, were Dr. Ottavia Filini, Dr. Alessandro Boldini and Dr. Jacopo Zilioli of our team, Francesco Versaci (CSO, Florence), Vito Romano (University of Brescia), Kieren Darcy and Stephen Taylor (Vision Care Clinic, Bristol), Valerio Bo (Casa della Salute, Genoa) and Giacomo Savini (IRCCS Fondazione Bietti, Rome).
What it means for patients
An objective defocus curve, obtained in a few seconds, makes it possible to assess the result of a premium lens in a repeatable way that can be compared across different centres. In the future it will help compare lenses with the same yardstick, follow the outcome over time and, once the measurement becomes available before surgery too, choose the most suitable lens for each eye. The authors are clear about the current limits: the method still has to be validated on diffractive lenses and on curves at different pupil sizes.
It is Dr. Russo’s 61st peer-reviewed publication, and his work has been cited more than 1,200 times in the scientific literature. Anyone considering cataract surgery with premium lenses or the correction of presbyopia can book a visit in the Ophthalmology department of Istituto Chirurgico Palazzo Manzoni in Brescia by calling +39 030 294 2437. You can read more about Dr. Russo’s profile.
Reference
Russo A, Versaci F, Romano V, Darcy K, Bo V, Filini O, Taylor S, Boldini A, Zilioli J, Savini G. Constructing an Objective Defocus Curve from Pyramidal Wavefront Aberrometry: Mapping Objective-to-Subjective Through-Focus Response. American Journal of Ophthalmology, 2026 Oct 29 (online, in press). DOI: 10.1016/j.ajo.2026.10.018. Open access.
