TY - JOUR
T1 - Stromal thermal effects induced by nonmechanical (2.94-μm) Erbium:YAG laser corneal trephination
AU - Behrens, Ashley
AU - Küchle, Michael
AU - Seite, Berthold
AU - Langenbucher, Achim
AU - Kus, Murat M.
AU - Amann, Thomas
AU - Schlötzer-Schrehardt, Ursula
AU - Rummelt, Carmen
AU - Naumann, Gottfried O.H.
PY - 1998
Y1 - 1998
N2 - Objective: To determine stromal thermal changes after erbium (Er):YAG laser corneal trephination with the use of 2 open masks. Methods: Corneal trephination was performed in 89 enucleated pig eyes with an Er:YAG laser (400-microsecond pulse duration), 4 open masks (2 metallic and 2 ceramic) for both donors and recipients, and an automated globe rotation device. Different combinations of laser settings were used: pulse energy, 100, 200, and 400 mJ; repetition rate, 2 and 5 Hz; and spot size, 1.3 and 3.2 min. Thermal effects in corneal stroma and regularity of the cut edges were quantitatively assessed by light microscopy, transmission and scanning electron microscopy. Results: Best regularity and minimal thermal effects of the cut were observed with the use of ceramic masks at 200 mJ, 2 Hz, and 3.2-mm spot size, with middepth thermal changes of 18 ± 2 μm. Effects increased with cut depth and were lower in donor corneas and with the use of ceramic masks (P<. 001). Regularity of the cut was higher in the donors (P=.05) with lower repetition rates (P<.001). Conclusions: Even with the 'free-running' Er:YAG laser mode, features of the trephination cut resembling those created by the 193-nm excimer laser along metal mask were achieved. Ceramic masks may be more suitable than metal masks. The Er:YAG laser seems to have the potential to be a compact and low-cost alternative in nonmechanical trephination for penetrating keratoplasty. Clinical Relevance: Thermal effects after corneal trephination with the free-running Er:YAG laser (2.94 mm) are limited and predictable.
AB - Objective: To determine stromal thermal changes after erbium (Er):YAG laser corneal trephination with the use of 2 open masks. Methods: Corneal trephination was performed in 89 enucleated pig eyes with an Er:YAG laser (400-microsecond pulse duration), 4 open masks (2 metallic and 2 ceramic) for both donors and recipients, and an automated globe rotation device. Different combinations of laser settings were used: pulse energy, 100, 200, and 400 mJ; repetition rate, 2 and 5 Hz; and spot size, 1.3 and 3.2 min. Thermal effects in corneal stroma and regularity of the cut edges were quantitatively assessed by light microscopy, transmission and scanning electron microscopy. Results: Best regularity and minimal thermal effects of the cut were observed with the use of ceramic masks at 200 mJ, 2 Hz, and 3.2-mm spot size, with middepth thermal changes of 18 ± 2 μm. Effects increased with cut depth and were lower in donor corneas and with the use of ceramic masks (P<. 001). Regularity of the cut was higher in the donors (P=.05) with lower repetition rates (P<.001). Conclusions: Even with the 'free-running' Er:YAG laser mode, features of the trephination cut resembling those created by the 193-nm excimer laser along metal mask were achieved. Ceramic masks may be more suitable than metal masks. The Er:YAG laser seems to have the potential to be a compact and low-cost alternative in nonmechanical trephination for penetrating keratoplasty. Clinical Relevance: Thermal effects after corneal trephination with the free-running Er:YAG laser (2.94 mm) are limited and predictable.
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U2 - 10.1001/archopht.116.10.1342
DO - 10.1001/archopht.116.10.1342
M3 - Article
C2 - 9790634
AN - SCOPUS:0031708016
SN - 0003-9950
VL - 116
SP - 1342
EP - 1348
JO - Archives of ophthalmology
JF - Archives of ophthalmology
IS - 10
ER -