PURPOSE: To analyze the interface quality of the anterior stroma after femtosecond laser flap creation using atomic force microscopy. SETTING: IRCCS Fondazione G.B. Bietti, Rome, Italy. DESIGN: Experimental study. METHODS: A 110 um depth flap was created in 20 human corneal tissues using a femtosecond laser platform (Intralase iFS). Tissues were divided into 4 groups of various cutting parameters: pulse energy and spot separation of 0.75 uJ and 6 um (Group 1), 0.65 uJ and 5 um (Group 2), 0.55 uJ and 4 um (Group 3), and 0.45 uJ and 4 um (Group 4). Four additional tissue sections were cut using a motorized microkeratome (Hansatome). Atomic force microscopy (Autoprobe CP) analysis was performed on the stromal bed of each sample. RESULTS: The corneal tissues treated with higher pulse energies and wider spot separations (Groups 1 and 2) showed a rougher stromal bed interface (root mean square [RMS] rough = 0.23 um +/- 0.008 (SD) and 0.24 +/- 0.009 um, respectively) than tissues in Groups 3 and 4 (RMS rough = 0.18 +/- 0.006 um and 0.18 +/- 0.008 um, respectively; P<.001, 1-way analysis of variance). The stromal surface quality of tissues treated with pulse energies of 0.55 uJ or lower and 4 um spot separation compared favorably with that of tissues cut by the microkeratome (RMS rough = 0.17 +/- 0.006 um; P>.05, Tukey). CONCLUSIONS: The femtosecond stromal interface quality was improved with pulse energy lower and spot separations narrower than those currently used in the clinical setting. The flap interface smoothness created by the femtosecond laser was comparable to that created by the microkeratome.
Optimal parameters to improve the interface quality of the flap bed in femtosecond laser-assisted laser in situ keratomileusis
DE SANTO, Maria Penelope;
2012-01-01
Abstract
PURPOSE: To analyze the interface quality of the anterior stroma after femtosecond laser flap creation using atomic force microscopy. SETTING: IRCCS Fondazione G.B. Bietti, Rome, Italy. DESIGN: Experimental study. METHODS: A 110 um depth flap was created in 20 human corneal tissues using a femtosecond laser platform (Intralase iFS). Tissues were divided into 4 groups of various cutting parameters: pulse energy and spot separation of 0.75 uJ and 6 um (Group 1), 0.65 uJ and 5 um (Group 2), 0.55 uJ and 4 um (Group 3), and 0.45 uJ and 4 um (Group 4). Four additional tissue sections were cut using a motorized microkeratome (Hansatome). Atomic force microscopy (Autoprobe CP) analysis was performed on the stromal bed of each sample. RESULTS: The corneal tissues treated with higher pulse energies and wider spot separations (Groups 1 and 2) showed a rougher stromal bed interface (root mean square [RMS] rough = 0.23 um +/- 0.008 (SD) and 0.24 +/- 0.009 um, respectively) than tissues in Groups 3 and 4 (RMS rough = 0.18 +/- 0.006 um and 0.18 +/- 0.008 um, respectively; P<.001, 1-way analysis of variance). The stromal surface quality of tissues treated with pulse energies of 0.55 uJ or lower and 4 um spot separation compared favorably with that of tissues cut by the microkeratome (RMS rough = 0.17 +/- 0.006 um; P>.05, Tukey). CONCLUSIONS: The femtosecond stromal interface quality was improved with pulse energy lower and spot separations narrower than those currently used in the clinical setting. The flap interface smoothness created by the femtosecond laser was comparable to that created by the microkeratome.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
