Original article
Ultra-Thin Donor Tissue Preparation for Endothelial Keratoplasty With a Double-Pass Microkeratome

https://doi.org/10.1016/j.ajo.2011.01.051Get rights and content

Purpose

To quantify and describe practically a novel technique for donor tissue preparation in Descemet stripping endothelial keratoplasty to approach the superior visual outcomes of Descemet membrane endothelial keratoplasty.

Design

Experimental laboratory investigation.

Methods

setting: Institutional. study population: Eleven human donor corneas. intervention: Double-pass of microkeratome over donor corneas—first with a thicker cutting depth and subsequently with a thinner cutting depth.

Main Outcome Measures

Donor tissue profiles and residual bed thicknesses.

Results

After the first pass of the microkeratome, the average cut thickness using the 250-μm cutting head was 342.5 ± 14.8 μm (range, 332 to 353 μm), that using the 300-μm head was 343.8 ± 39.2 μm (range, 315 to 411 μm), and that with the 350-μm head was 467.7 ± 50.1 μm (range, 419 to 519 μm). We used the 200-μm cutting head only once with a cut depth of 210 μm. For the second pass, when using the 110-μm head, the cutting depth averaged to 167.8 ± 28.8 μm (range, 133 to 203 μm). The 130-μm cutting head yielded a cut depth of 199.7 ± 24.4 μm (range, 180 to 227μm). Two corneas were perforated during the second pass. The average final thickness of the residual bed was 121 ± 32.2 μm (range, 52 to 160 μm).

Conclusions

Double-pass harvest for ultra-thin Descemet stripping automated endothelial keratoplasty could improve optical outcomes by obtaining donor Descemet stripping automated endothelial keratoplasty tissue with thinner residual beds. Further studies are needed with larger sample sizes to establish algorithms for appropriate cutting head thickness in each pass. Potential additional endothelial cell loss with the second pass of the microkeratome also should be evaluated.

Section snippets

Methods

Eleven human corneoscleral rims donated for research (Utah Lions Eye Bank, Salt Lake City, Utah, USA) were mounted in an artificial anterior chamber (ALTK System; Moria/Microtech, Doylestown, Pennsylvania, USA). All corneas were harvested uniformly by in situ excision and were place immediately into the Optisol (Bausch & Lomb, St Louis, Missouri, USA) medium when harvested; therefore, the death-preservation time was the same as death-retrieval time. The anterior chamber was filled with Optisol

Results

The average age ± standard deviation of the 11 donors was 48.3 ± 17 years (range, 24 to 73 years). The average death to preservation time ± standard deviation was 7.4 ± 5 hours (range, 2.4 to 15.9 hours). The average storage time ± standard deviation was 23 ± 6.7 days (range, 10 to 31 days; Table).

The average ± standard deviation initial corneal thickness was 651.7 ± 92.9 μm (range, 519 to 813 μm). The superficial free cap was created during the first pass using 200-μm, 250-μm, 300-μm, and

Discussion

Currently, DSAEK donor harvesting involves the use of a microkeratome to remove corneal stroma. Historically, when the precut donor CCT exceeds 570 μm after epithelium removal, a 350-μm microkeratome head is used, whereas a 300-μm head is used when CCT is less than 570 μm.6 Although the average thickness of DSAEK donor tissue has been evaluated by Terry and associates, the reproducibility and thickness profile after microkeratome passage has not been evaluated in vitro.8 Nonuniform thickness of

Majid Moshirfar, MD, is a Professor of Ophthalmology the University of Utah and director of the Moran Eye Center's Refractive Surgery Program, Salt Lake City, Utah. Dr. Moshirfar specializes in refractive surgery, medical and surgical management of corneal disorders, cataract surgery and inflammatory eye diseases.

Majid Moshirfar, MD, is a Professor of Ophthalmology the University of Utah and director of the Moran Eye Center's Refractive Surgery Program, Salt Lake City, Utah. Dr. Moshirfar specializes in refractive surgery, medical and surgical management of corneal disorders, cataract surgery and inflammatory eye diseases.

Shameema Sikder, MD, is currently a cornea and refractive surgery fellow at the Moran Eye Center, University of Utah, Salt Lake City, Utah. She studied medicine at the University of Arizona and completed her residency at the Wilmer Eye Institute, Johns Hopkins University. She is soon to return to the Wilmer Eye Insitute as the Assistant Chief of Service and an Assistant Professor of Ophthalmology.

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