Investigating the ocular temperature rise during femtosecond laser lens fragmentation: an in vitro study.
OBJECTIVE
To investigate the trend of temperature variation during lens fragmentation simulated by a femtosecond laser on an in vitro eye model.


METHODS
In our experimental study, a convex cylinder of gelatinous material, usually employed in femtosecond laser calibration, was used to simulate both an anterior segment and a crystalline lens during fragmentation performed with the Victus femtosecond laser (Technolas Perfect Vision GmbH, Germany; Bausch + Lomb Incorporated, USA). Two radiated energies (7000 nJ and 9000 nJ) and three cutting patterns (crosses, circles and cross + circle) were applied. Trends of temperature variation as a function of time were obtained using a T-type thermocouple.


RESULTS
The maximum value of temperature rise during lens fragmentation ranged from 3.53 to 5.13 °C; the rise was directly proportional to the intensity of the radiated energy (7000 nJ or 9000 nJ) and the cutting pattern performed. This behavior was experimentally represented by an asymmetric function with a characteristic bell curve shape, whereas it was mathematically described by a transport diffusive model.


CONCLUSIONS
Since the temperature rise at the fragmentation volume base resulted to be around 5 °C in our in vitro study, lens fragmentation performed using the Victus femtosecond laser might be considered safe form a thermal point of view.
Department of Surgery and Translational Medicine, Eye Clinic, University of Florence, Largo Brambilla 3, 50134, Florence, Italy. rita.mencucci@unifi.it.
Rita
R
Mencucci
Department of Industrial Engineering, University of Florence, Florence, Italy.
Sara
S
Matteoli
Department of Industrial Engineering, University of Florence, Florence, Italy.
Andrea
A
Corvi
Department of Surgery and Translational Medicine, Eye Clinic, University of Florence, Largo Brambilla 3, 50134, Florence, Italy.
Luca
L
Terracciano
Department of Surgery and Translational Medicine, Eye Clinic, University of Florence, Largo Brambilla 3, 50134, Florence, Italy.
Eleonora
E
Favuzza
INFN, CSDC, Department of Information Engineering, University of Florence, Florence, Italy.
Stefano
S
Gherardini
QSTAR, LENS, Department of Physics and Astronomy, University of Florence, Florence, Italy.
Filippo
F
Caruso
Ophthalmic Unit, University Hospital, Verona, Italy.
Roberto
R
Bellucci
D000869:Anterior Eye Segment / Q000502:physiology*; D001831:Body Temperature / Q000502:physiology*; D002387:Cataract Extraction; D006801:Humans; D066298:In Vitro Techniques; D053685:Laser Therapy; D008954:Models, Biological; D013817:Thermography; D013997:Time Factors
Cataract; Eye temperature; Femtosecond laser; Femtosecond laser-assisted cataract surgery