Scanning electron microscopic evaluation of the surface characteristics of 4 microkeratome systems in human corneas.
OBJECTIVE
To evaluate the surface characteristics of keratectomy specimens created with 4 microkeratomes by scanning electron microscopy (SEM).


METHODS
Two university institutions.


METHODS
Keratectomies were performed in 10 fresh, unfrozen human eyes with 1 of 4 microkeratomes: the Draeger rotary microkeratome (Storz Instruments), the Universalkeratome (Phoenix), the Automated Corneal Shaper (Bausch & Lomb), or the Hansatome (Bausch & Lomb). The beds and edges of the keratectomy specimens were then examined by SEM. Standardized photographs were taken, and the surface and cut-edge characteristics of the keratectomies were compared.


RESULTS
Irregularities were noted in the cut edges of Bowman's membrane and the surface of the keratectomy beds with all instruments. The irregularities were most prominent in corneas cut with the Draeger instrument and least prominent in those cut with the Universalkeratome. The serrations in Bowman's membrane and the irregularities in the keratectomy bed appeared to be related to the blade movement in oscillating blade instruments.


CONCLUSIONS
All 4 microkeratomes caused some degree of surface irregularity. The Draeger microkeratome, which uses a continuously rotating blade, resulted in the greatest number of Bowman's membrane serrations and irregularities in the keratectomy bed. The tissue irregularities may be related to the development of pressure ridges ahead of the blade. In instruments that use an oscillating blade, chatter marks appear to be related to the reciprocating movement of the blade as it travels across the corneal stroma.
Hamill
M Bowes
MB
Cullen Eye Institute, Baylor College of Medicine, Department of Ophthalmology, Houston, Texas 77030, USA. mhamill@bcm.tmc.edu
Kohnen
Thomas
T
D003315:Cornea / Q000601:surgery* / Q000648:ultrastructure*; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000295:instrumentation*; D008855:Microscopy, Electron, Scanning; D013524:Surgical Flaps