# Objective defocus curve after intraocular lens implantation built from one Osiris aberrometer scan in 98 eyes

- Published: 2026-11-14 21:18 UTC
- Section: Life & Health › Medicine
- Tags: objective defocus curve, Osiris pyramidal aberrometer, intraocular lens, extended depth of focus, cataract surgery, presbyopia, American Journal of Ophthalmology, CSO Florence, Gruppo Refrattivo Italiano, logMAR
- URL: https://realtech.media/news/rt-ce935981ee5482b7dbf40bd8_objective_defocus_curve/

**GRI, CSO and the University of Brescia derived a defocus curve in seconds, replacing a 10–15 minute subjective test. The study covered 98 eyes of 63 patients.**

![Objective defocus curve after intraocular lens implantation built from one Osiris aberrometer scan in 98 eyes](https://realtech.media/media/2026/11/73bc909c2150c37c.jpg)
*Tony Webster, Wikimedia Commons, CC BY 2.0*

On 10 November 2026, adnkronos.com reported that the American Journal of Ophthalmology had published an open-access multicentre study coordinated by Andrea Russo of the Gruppo Refrattivo Italiano (GRI). The work was done with the research department of CSO (Florence) and Vito Romano of the University of Brescia. The authors propose an objective defocus curve for eyes after intraocular lens implantation for cataract or presbyopia. It is obtained in a few seconds from a single acquisition of the Osiris pyramidal aberrometer. [1]

## Why the defocus curve matters

The defocus curve is a graph showing how many lines of the visual acuity chart a patient reads at each distance. It is used to evaluate multifocal and extended depth of focus lenses. Until now it could only be obtained subjectively: 10–15 minutes of readings through a sequence of lenses. The result depends on the patient's cooperation and the examiner's experience. [1]

## Method and results

The study included 98 eyes of 63 patients operated with the RayOne Galaxy lens at three centres: Brescia, Bristol and Genoa. Each eye was examined with the Osiris aberrometer, developed and manufactured by CSO in Florence. In one acquisition it records how the eye bends light. From that measurement an algorithm simulates blur at each distance and converts it into chart lines, so the patient is asked to do nothing. The method was then checked on an external cohort of 19 eyes operated in Bologna with other extended depth of focus lenses. [1]

According to the authors, the objective and subjective curves differ on average by less than one chart line. The root mean square error was 0.095 logMAR in the verification group and 0.092 in the external cohort, with limits of agreement of about ±0.2 logMAR. The depth of focus estimated by the instrument matched the one measured on patients to within 0.1–0.15 diopters. With the studied lens, 88.8% of eyes reached 10/10 at distance. [1]

The algorithm was developed by the CSO research department with Francesco Versaci. Other participants were Kieren Darcy and Stephen Taylor (Vision Care Clinic, Bristol), Valerio Bo (Casa della Salute, Genoa), Giacomo Savini (IRCCS Fondazione Bietti, Rome) and GRI surgeons Ottavia Filini, Alessandro Boldini and Jacopo Zilioli. The Italian patients were operated on and measured at the GRI site in Brescia. [1]

The authors say the objective curve makes it possible to assess a premium lens in a repeatable way that can be compared between centres. They name the current limits: the method still has to be validated on diffractive lenses and on curves at different pupil sizes. The material is a press release published under the editorial responsibility of GRI. [1]

## Sources

1. [adnkronos.com](https://www.adnkronos.com/immediapress/dalla-ricerca-italiana-un-nuovo-modo-di-misurare-la-vista-dopo-limpianto-di-lenti-intraoculari-studio-pubblicato-sullamerican-journal-of-ophthalmology_2unpAPb8n385XnBRc2cNl6)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-ce935981ee5482b7dbf40bd8_objective_defocus_curve/