Femtosecond laser top hat penetrating keratoplasty: wound burst pressures of incomplete cuts.
OBJECTIVE
To investigate the pressure required to rupture femtosecond laser top hat configuration corneal dissections with incomplete dissections.


METHODS
Twenty corneoscleral buttons underwent femtosecond laser top hat configuration dissections. Group A had complete dissections; group B, 100-microm gaps in the anterior side cut; group C, 50-microm gaps in the anterior side cut; group D, 100-microm gaps in the lamellar cut; and group E, 50-microm gaps in the lamellar cut. The pressure required to rupture each cornea was measured.


RESULTS
The mean (SD) pressure required to rupture the corneas was 111 (74) mm Hg for group A, 1565 (509) mm Hg for group B, 747 (209) mm Hg for group C, 550 (303) mm Hg for group D, and 392 (166) mm Hg for group E (P = .03 for all compared with group A).


CONCLUSIONS
Incomplete femtosecond laser top hat dissections are highly resistant to rupture by direct pressurization. Gaps in the anterior side cuts are stronger than comparably sized gaps in the lamellar cuts. Clinical Relevance Undertaking femtosecond laser keratoplasty in a 2-site setting should, theoretically, have a high level of safety. Burst pressures are high enough to resist an inadvertent sudden increase in intraocular pressure providing that incomplete recipient laser dissections are undertaken.
Department of Ophthalmology, Toronto Western Hospital and University of Toronto, Toronto, Ontario, Canada. pennym@actrix.gen.nz
Penny
P
McAllum
Igor
I
Kaiserman
Irit
I
Bahar
David
D
Rootman
D000328:Adult; D000368:Aged; D002102:Cadaver; D003315:Cornea / Q000503:physiopathology / Q000601:surgery*; D065306:Corneal Injuries; D004210:Dissection / Q000379:methods; D006801:Humans; D066298:In Vitro Techniques; D015948:Keratoplasty, Penetrating / Q000379:methods*; D053685:Laser Therapy / Q000379:methods*; D008365:Manometry; D008875:Middle Aged; D011312:Pressure; D012421:Rupture / Q000209:etiology*; D013718:Tensile Strength; D013997:Time Factors