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Natalie Stanciu, MD Richard M. Awdeh, MD Takeshi Ide, MD Sonia Yoo, MD Bascom Palmer Eye Institute ASCRS 2009: San Francisco

Natalie Stanciu, MD Richard M. Awdeh, MD Takeshi Ide, MD Sonia Yoo, MD Bascom Palmer Eye Institute ASCRS 2009: San Francisco

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Page 1: Natalie Stanciu, MD Richard M. Awdeh, MD Takeshi Ide, MD Sonia Yoo, MD Bascom Palmer Eye Institute ASCRS 2009: San Francisco

Natalie Stanciu, MD

Richard M. Awdeh, MD

Takeshi Ide, MD

Sonia Yoo, MD

Bascom Palmer Eye Institute

ASCRS 2009: San Francisco

Page 2: Natalie Stanciu, MD Richard M. Awdeh, MD Takeshi Ide, MD Sonia Yoo, MD Bascom Palmer Eye Institute ASCRS 2009: San Francisco

45,000 PKP are performed annually in the US, 45% include cases of corneal damage limited to endothelium.

DSAEK: popular alternative to PKP. Most DSAEK tissue is cut with microkeratome Limitations of microkeratome: inability to control the thickness and shape of donor

tissue. One potential reason why BCVA after DSAEK

rarely 20/20.

Page 3: Natalie Stanciu, MD Richard M. Awdeh, MD Takeshi Ide, MD Sonia Yoo, MD Bascom Palmer Eye Institute ASCRS 2009: San Francisco

Recently the use of Femtosecond laser has been entertained as an alternative to mechanical mickrokeratome.

Advantage: Ability to control thickness and predictable shape.

Challenge is achieving smooth surface: a problem less encountered by microkeratome.

Page 4: Natalie Stanciu, MD Richard M. Awdeh, MD Takeshi Ide, MD Sonia Yoo, MD Bascom Palmer Eye Institute ASCRS 2009: San Francisco
Page 5: Natalie Stanciu, MD Richard M. Awdeh, MD Takeshi Ide, MD Sonia Yoo, MD Bascom Palmer Eye Institute ASCRS 2009: San Francisco

Variables which can affect smoothness Low vs. High Energy

Single vs. Multiple PassLaser pattern: Raster vs. Spiral

In this pilot study, we compared relative smoothness of femtosecond-cut tissue using several different combinations of above variables.

We predict that Raster, Low, Multiple pass should produce the smoothest surface.

Page 6: Natalie Stanciu, MD Richard M. Awdeh, MD Takeshi Ide, MD Sonia Yoo, MD Bascom Palmer Eye Institute ASCRS 2009: San Francisco

Group Energy Spot Separation(microns)

Line

RasterLowSingle

1.0 6 6

Raster LowMultiple

1.0 6 6

RasterHighSingle

1.9 11 9

Spiral Low Multiple

1.0 6 6

Page 7: Natalie Stanciu, MD Richard M. Awdeh, MD Takeshi Ide, MD Sonia Yoo, MD Bascom Palmer Eye Institute ASCRS 2009: San Francisco

Fresh porcine eyes(n=2 for each group)

30 kHz INTRALASE Femtosecond laser was used to cut cornea flap.

Following the procedure, the donor tissue was immersed in fixative.

Scanning Electron microscopy(SEM) was used to assess relative smoothness of tissue.

Page 8: Natalie Stanciu, MD Richard M. Awdeh, MD Takeshi Ide, MD Sonia Yoo, MD Bascom Palmer Eye Institute ASCRS 2009: San Francisco

Raster Low Single

Raster Low Multiple

Raster High Single

Spiral Low Multiple

Page 9: Natalie Stanciu, MD Richard M. Awdeh, MD Takeshi Ide, MD Sonia Yoo, MD Bascom Palmer Eye Institute ASCRS 2009: San Francisco

Raster Low Single pass appeared to have smoothest surface.

Contradicts expected results however possible error introduced when multiple pass done in different directions.

Observed that easier to lift flap with multiple pass than single.

Overall raster smoother than spiral.

Page 10: Natalie Stanciu, MD Richard M. Awdeh, MD Takeshi Ide, MD Sonia Yoo, MD Bascom Palmer Eye Institute ASCRS 2009: San Francisco

Delay between fixating tissue and sending for SEM (environmental).

Challenge interpreting SEM picture without bias.

Sample size low. Femtosecond 30kH machine used here

may make extrapolating results to other laser machine difficult.

Page 11: Natalie Stanciu, MD Richard M. Awdeh, MD Takeshi Ide, MD Sonia Yoo, MD Bascom Palmer Eye Institute ASCRS 2009: San Francisco

Ideal to use human eyes in the future, using pig eyes may have introduced some error and difficulty in applying results.

Possible use of software programs to quantify analysis of SEM photos.

Principles applied here can hopefully bring us closer to achieving perfect visual outcome following DSAEK.

Page 12: Natalie Stanciu, MD Richard M. Awdeh, MD Takeshi Ide, MD Sonia Yoo, MD Bascom Palmer Eye Institute ASCRS 2009: San Francisco

References:Sarayaba MA et al. Femtosecond Laser Posterior Lamellar Keratoplasty.

Cornea. 2005;24:328-333.Suwan-apichon O et al. Mickrokeratome Versus Femtosecond Laser

Predissection of Corneal Grafts for Anterior and Posterior Lamellar Keratoplasty. Cornea. 2006;25:966-968.

Binder PS et al. Characterization of Submicrojule femtosecond laser corneal tissue dissection. J Cataract Refractive Surgery. 2008;34:146-152.

Terry MA, Ously PJ. Replacing the endothelium without corneal surface incisions or sutures:the first United States clinical series using the deep lamellar endothelial keratoplasty procedure. Ophthalmology. 2003;110:755-764.

Terry MA, Ously PJ. Endothelial replacement without surface corneal incisions or sutures: topography of the deep lamellar endothelial keratoplasty procedure.

Aiken-Oneil P, Mannis MJ. Summary of corneal transplant activity Eye Bank association of America. Cornea. 2002;21:1-3.