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Femtosecond Laser-Assisted Decagonal PenetratingKeratoplasty

HÉLÈNE PROUST, CHRISTOPHE BAETEMAN, FRÉDÉRIC MATONTI, JOHN CONRATH,

BERNARD RIDINGS, AND LOUIS HOFFART

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PURPOSE: To assess the use of a new polygonal treph-nation pattern for penetrating keratoplasty (PK) assistedy femtosecond laser.DESIGN: Prospective, nonrandomized clinical study.METHODS: Sixteen eyes underwent decagonal PK.ine had Fuchs dystrophy, 4 had pseudophakic bullouseratopathy, 1 had experienced trauma, 1 had cornealmyloidosis, and 1 had keratoconus. A Femtec (TecnolaserfectVision) laser was used to create decagonal pene-rating cuts on both donor and recipient corneas. Allatients were evaluated for uncorrected visual acuity,est spectacle-corrected visual acuity, pachymetry, to-ography, and endothelial cell density. Scanning electronicroscopy was performed on corneal tissue after sur-

ery.RESULTS: All eyes were treated successfully without

ntraoperative complications. The mean follow-up �tandard deviation was 9.75 � 3.5 months. Mean post-perative best spectacle-corrected visual acuity was 20/3, and there was a significant improvement in bothncorrected visual acuity (P � .0019) and best specta-le-corrected visual acuity (P � .001). At 6 months,ean � standard deviation manifest astigmatism was.90 � 1.20 diopters. Mean endothelial cell density was502 � 458 cells/mm2. Scanning electron microscopyisplayed straight decagonal cut margins and minor re-aining tissue bridges.CONCLUSIONS: Use of the decagonal trephination pro-

le was effective and safe to perform PK. Short-termisual results and refractive results are encouragingompared with those of conventional PK studies. Longer-erm follow-up and comparative studies are necessary toetermine precisely advantages the and optimal surgicalettings of this technique. (Am J Ophthalmol 2011;51:29–34. © 2011 by Elsevier Inc. All rights reserved.)

INCE THE FIRST HUMAN FULL-THICKNESS CORNEAL

transplantation, performed by Zirm in 1906, pene-trating keratoplasty (PK) has grown to be the most

requently performed tissue transplant in the world.1 Sur-

ccepted for publication July 20, 2010.From the Department of Ophthalmology, Aix-Marseille University,opital de la Timone Adultes, Marseille, France (H.P., C.B., F.M., J.C.,.R., L.H.).Inquiries to Louis Hoffart, Service d’Ophthalmologie, Hopital de la

uimone Adultes, 264 rue Saint-Pierre, 13385 Marseille cedex 05, France;-mail: louis.hoffart@ap-hm.fr

© 2011 BY ELSEVIER INC. A002-9394/$36.00oi:10.1016/j.ajo.2010.07.016

ical improvements lead to a gradual change in proceduresver the next several decades. High astigmatism is one ofhe major issues that can compromise a patient’s visualehabilitation after PK.2 Numerous procedures have beenested to correct astigmatic errors, including relaxingrocedures, wedge resections, and photorefractive proce-ures.3–9 Femtosecond laser is a step forward in theefinement of corneal surgery. By performing the samerephination profile on both donor and recipient tissue,aser-assisted surgery may improve wound adaptation andisual outcomes.10

The femtosecond laser is a focusable infrared laser thatelivers ultrashort pulses in the femtosecond durationange. Contiguous pulses are placed at a definite depthithin the cornea, thus resecting only targeted tissue. This

urgical device allows cutting of corneal tissue in a numberf transplant designs and allows the use of sagittal planerephination profiles, such as zigzag,11,12 top-hat,13 Christ-as tree,14 and mushroom15 shapes to improve wound

tability14 and to reduce postoperative astigmatism.11 Theechnolas laser (Technolas PerfectVision, Heidelberg,ermany) can be used to create additional geometric

onfigurations to increase the postoperative results oferatoplasty. Herein, we report outcomes of a decagonal-haped PK cut profile using a femtosecond laser.

METHODS

LL SURGERIES WERE PERFORMED IN OUR DEPARTMENT

rom November 2007 through April 2008. All proceduresere performed by one surgeon (H.P.). Corneal trephina-

ion was performed using a Technolas laser. This apparatusonsists of a pulsed solid body (neodymium:glass) laserith a repetition rate of 40 kHz that emits light with aavelength of 1055 nm and a pulse duration of 800

emtoseconds. The laser was set to obtain a decagonalorneal button of 8.0-mm decagonal trephination ononor tissue and an 8.0-mm decagonal trephination onecipient tissue. The cut rim angle was set at 90 degrees tohe corneal surface tangent. Laser beam energy of 3.2 to.4 �J and a spot separation of 3 �m were chosen. Aouble-pass procedure was used to reduce the amount ofesidual tissular bridges and to ease the opening of theound (the first laser cut started from 1300 to 200 �m

nder the corneal surface and a second laser cut followed

LL RIGHTS RESERVED. 29

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he same pattern up to the surface). Donor corneoscleraliscs were mounted on an artificial anterior chamberMoria, Anthony, France) filled with BSS plus (Alcon,ort Worth, Texas, USA) up to a pressure of 20 mm Hg.orneal thickness subsequently was determined by ultra-

ound pachymetry (UP-1000; Nidek, Tokyo, Japan). Cor-eoscleral discs were placed under the laser through aoncave patient interface and were centered using theeflex image of the diode lights of the laser. After trephi-ation, the corneal button was separated by blunt dissec-ion with a Sinskey manipulator (Moria, Anthony,rance). On the recipient, the procedure required place-ent of a suction ring. After a proper vacuum seal was

btained, the patient interface was applied and the laserrocedure was performed as previously described. Afterompletion of the cut, the eye was disconnected from theaser and the corneal button was removed by dissectionith a blunt hook. The corneal graft then was positionedn the recipient eye after filling of the anterior chamberith a cohesive viscoelastic (Healon GV; AMO, Ettlin-en, Germany) and was secured by a combination of 10nterrupted sutures on each angle of the decagon, then a0-bite running suture was added on the middle of eachecagon side. After surgery, patients received tobramycinlus dexamethasone eyedrops (TobraDex; Alcon) 3 timesaily for 1 month and then slowly tapered. Selective sutureemoval was performed starting at the first-month visit ifstigmatism was more than 3 diopters (D).

Postoperative examinations were planned at 7 days andt 1, 3, 6, 9, and 12 months. The following data werevaluated: uncorrected visual acuity, best spectacle-cor-ected visual acuity, slit-lamp biomicroscopy, and dilated

TABLE 1. Decagonal Keratoplasty with the Technolas

Patient No. Gender Age (yrs) Eye

1 F 82 Left

2 M 28 Left

3 F 77 Right

4 M 72 Left

5 F 80 Left

6 F 82 Left

7 M 78 Right

8 M 55 Left

9 F 80 Left

10 F 92 Right

11 M 90 Right

12 M 72 Left

13 M 72 Right

14 F 80 Left

15 F 21 Left

16 F 82 Left

ARMD � age-related macular degeneration; DSAEK � Descemet

years.

undus examination. All visual acuity data were converted r

AMERICAN JOURNAL OF0

o logarithm of minimal angle of resolution units. Statis-ical analysis was performed using SPSS software version3.0 (SPSS, Inc, Chicago, Illinois, USA). The Wilcoxonank-sum test was used to assess the difference betweenxaminations. A P value � .05 was considered significant.ndothelial cell density and central corneal pachymetryere obtained by noncontact specular microscopy (Top-on SP-2000 and ImageNet Computerized Analysis Sys-em; Topcon, Tokyo, Japan).

Objective astigmatism, specular corneal topography,urface regularity index, surface asymmetry index, and the

IGURE 1. Slit-lamp photographs showing postoperative fea-ures of decagonal keratoplasty with the Technolas femtosecondaser. (Left) Slit-lamp photograph of decagonal-shaped cut pene-rating keratoplasty at 1 month. (Right) Perfect apposition ofonor and recipient wounds (white arrow). Running sutureenetrates in the middle of each side of the polygon (black arrow).

tosecond Laser: Patient Demographic Characteristics

Primary Diagnosis Secondary Diagnosis

ed DSAEK ARMD

neal amyloidosis None

udophakic bullous keratopathy ARMD

hs dystrophy Allograft rejection

ed DSAEK None

hs dystrophy None

udophakic bullous keratopathy None

udophakic bullous keratopathy None

hs dystrophy None

hs dystrophy None

hs dystrophy Macular edema

uma Epiretinal membrane

hs dystrophy Diabetic macular edema

hs dystrophy None

atoconus None

udophakic bullous keratopathy None

ated stripping endothelial keratoplasty; F � female; M � male; yrs �

Fem

Fail

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OPHTHALMOLOGY JANUARY 2011

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can station (ARK 10000; NIDEK). All patients under-ent anterior segment optical coherence tomography tovaluate wound alignment and suture configurations (Stra-us OCT 3; Carl-Zeiss Meditec, Inc, Jena, Switzerland).ll donor corneoscleral rims and recipients corneal but-

ons were fixed with 2.5% glutaraldehyde for scanninglectron microscopy (Philips XL 30S, Amsterdam, Theetherlands).

RESULTS

IXTEEN EYES OF 16 PATIENTS (7 MEN AND 9 WOMEN) WITH

mean age � standard deviation (SD) of 71.4 � 20.1 yearsrange, 21 to 92 years) underwent decagonal penetratingeratoplasty. Mean follow-up � SD was of 9.75 � 3.5onths. Surgical indication was Fuchs dystrophy in 9

atients (56.25%), pseudophakic bullous keratopathy in 4atients (25%), keratoconus in 1 patient (6.25%), trauman 1 patient (6.25%), and corneal amyloidosis in 1 patient6.25%). Preoperative examination showed 2 cases ofge-related macular degeneration, 1 case of diabetic mac-lar edema, and 1 case of epiretinal macular membrane.All procedures were uneventful. After surgery, 1 case ofacular edema was diagnosed and 1 patient showed a

etinal detachment at the third postoperative month andequired subsequent surgery. Demographic and diagnosticata are summarized in Table 1. A perfect wound apposi-ion was observed in all cases, as illustrated in Figure 1. Anarly and transient postoperative corneal edema was noted

TABLE 2. Decagonal Keratoplasty with the T6 Months

Patient No.

Preoperativ

UCVA

1 20000

2 2000

3 2000

4 200

5 2000

6 2000

7 2000

8 60

9 200

10 2000

11 2000

12 400

13 200

14 2000

15 400

16 2000

Mean � standard deviation (lines) 20/783 �

BSCVA � best spectacle-corrected visual acu

round the surgical wound after laser exposure; complete 1

DECAGONAL PENETRATIOL. 151, NO. 1

esolution was observed after 7 days. Epithelialization wasompleted after 3 days in all cases.

Visual outcomes are summarized in Tables 2 and 3.ignificant differences between preoperative and postop-rative uncorrected visual acuity and best spectacle-cor-ected visual acuity were observed (P � .0019 and P �0010, respectively). If the 5 cases of preoperative retinalmpairment were excluded from the analysis, postoperativencorrected visual acuity and best spectacle-correctedisual acuity would have been 20/54 � 0.12 (range, 20/100o 20/33) and 20/33 � 0.10 (range, 20/50 to 20/25),espectively.

Refractive data for each patient are summarized in Table. Mean � SD postoperative spherical equivalent was.10 � 1.83 D (range, �0.88 to 5.00 D). Mean � SDanifest and topographic postoperative astigmatism were

olas Femtosecond Laser: Visual Acuity atSurgery

Preoperative

BSCVA

Postoperative

UCVA

Postoperative

BSCVA

20000 2000 2000

200 63 32

200 400 400

200 32 32

2000 100 40

160 50 40

2000 63 25

50 50 30

200 50 50

2000 63 25

2000 100 100

133 40 40

133 400 63

80 50 40

100 50 25

2000 50 30

20/356 � 7.1 20/82 � 4.6 20/53 � 5

CVA � uncorrected visual acuity.

TABLE 3. Decagonal Keratoplasty with the TechnolasFemtosecond Laser: Visual Acuity Results at 6 Months

after Surgery

Variable

Mean UCVA Mean BSCVA

LogMAR Snellen LogMAR Snellen

Initial examination 1.59 � 0.60 20/783 1.25 � 0.71 20/356

Final examination 0.61 � 0.46 20/82 0.42 � 0.50 20/53

P value .0019 .001

BSCVA � best spectacle-corrected visual acuity; logMAR �

logarithm of minimal angle of resolution; UCVA � uncorrected

visual acuity.

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range, 0.89 to 5.73 D), respectively. Mean � SD postop-rative root mean square was 2.00 � 1.29 D (range, 0.69 to.90 D), surface regularity index was 1.39 � 0.36 (from.56 to 2.13), and the surface asymmetry index was 1.33 �.80 (from 0.52 to 3.91). At 6 months, mean � SD centralorneal pachymetry and endothelial cell density were08 � 32 �m and 1502 � 458 cells/mm2, respectively.

DISCUSSION

ECENT CORNEAL GRAFT TECHNIQUES, INCLUDING LAMEL-

ar keratoplasty procedures, offer significant advantagesver conventional PK, but they cannot address the fullange of corneal diseases and show limitations.16–18 Thisuggests that improvements in PK will result in significantenefits to patients. PK involves a skilled trephinationechnique to avoid irregular or decentered cuts that couldead to astigmatism and high refractive errors.19 Optimalostoperative outcome is dependent on a centered perpen-icular cut and a well-matched donor button to recipiented.20 Limitations of manual trephination include inaccu-ate cut of donor and recipient corneal edges, leading tootential graft–host wound mismatch.21 Advantages of-ered by laser-assisted keratoplasty consist of strongeround healing by better wound adaptation22 and reduc-

ion of corneal astigmatism by performing same cut profilen both donor and recipient.12,13 Decagonal keratoplasty isnew trephination pattern that may allow optimizing

TABLE 4. Decagonal Keratoplasty with theMonths

Patient No.

Postoperative Man

Sphere

1 �1.00

2 0.25

3 �1.50

4 �5.00

5 0.00

6 0.75

7 0.25

8 �1.25

9 �2.50

10 0.25

11 �2.00

12 0.00

13 4.00

14 �0.50

15 �3.00

16 �2.25

Mean � standard deviation �0.8 � 1.9

D � diopters; ECD � endothelial cell density;

rence of topographic sim K measurements.

ostoperative refractive results of full-thickness kerato- p

AMERICAN JOURNAL OF2

lasty. To our knowledge, this study is the first report ofemtosecond-assisted decagonal keratoplasty outcomes inhe literature.

Femtosecond laser is a focusable infrared laser thatelivers ultrashort pulses in the femtosecond durationange. Contiguous pulses are placed at a precise depthithin the cornea. The laser spot may be fired in a verticalattern for trephination cuts or parallel to the cornealurface to achieve lamellar cuts. At the moment, thenited States Food and Drug Administration approve 4

asers for corneal surgery: IntraLase (IntraLase Corp,rvine, California, USA), Technolas (Tecnolas Perfectvi-ion), Femto LDV (Ziemer Ophthalmic Systems AG, Port,witzerland), and the VisuMax laser (Carl Zeiss MeditecG, Jena, Germany). The salient feature of the Technolas

aser is a curved patient interface that minimizes thentraocular pressure rise during surgery and induces lessosterior stromal distortion during aplanation.23

Compared with mechanical PK, femtosecond laser-ssisted PK creates a more stable wound configura-ion12,14,22,24,25 by producing accurate cuts that allow aetter fit between donor and recipient. A better appo-ition between tissues was observed, and consequently,aster healing was associated with an earlier functionalecovery.13 Several transplant forms have been reportedn previous studies. Most of them concern the top-hatrofile that was found to be biomechanically more stablehan the traditional circular, mushroom, zigzag, orhristmas tree designs.14 Price and Price reported 1-year

nolas Femtosecond Laser: Outcomes at 6Surgery

efraction (D)

� K (D)

Postoperative ECD

(cells/mm2)Cylinder

2.00 5.73 2000

1.50 3.54 1200

1.50 1.80 946

2.00 2.25 1216

0.00 2.65 950

2.00 2.79 1400

3.00 4.04 1751

0.75 0.69 1600

3.00 2.45 2500

1.50 2.93 1830

2.00 1.45 993

0.00 4.44 1400

2.00 2.49 800

1.50 2.33 2000

5.00 5.38 1840

2.50 3.43 1600

.9 � 1.2 3.1 � 1.2 1502 � 458

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OPHTHALMOLOGY JANUARY 2011

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hat this configuration allowed for an increased area ofound healing.13 Farid and associates reported similarlyood results using a zigzag profile.12 Moreover, it seemsogical that the suture pattern and the shape of theransplant influence rotation and that the rotationalbility of the graft is greater with the zigzag form andraditional round form than with a decagonal or non-ircular form.

The use of a polygonal trephination pattern may im-

IGURE 2. Scanning electron microscopy image showing do-or corneoscleral rims after decagonal keratoplasty with theechnolas femtosecond laser. Note the angle of the decagonal-

haped cut (white arrow) and the straight, orthogonal, and crisprephination edge. The stromal surface of the recipient showedinor remaining tissue bridges.

rove the outcomes of keratoplasty. Moreover, femtosec- s

sion sutures in treatment of high astigmatism after perforat-

DECAGONAL PENETRATIOL. 151, NO. 1

nd laser-assisted corneal graft procedures may gaintability and improved centration from noncircular trans-lant shapes. The advantages of the decagonal cut com-ared with circular transplants consist of the absence ofotation or decentration during the procedure, the decagonorners being distributed evenly over the entire transplanteriphery, which is then optimally protected against rota-ions. The decagonal shape decreases the torque effectssociated with a circular graft during suture placementnd allows a stable fitting of the graft into the recipient,ecause it provides the strength of an circular shape withhe stability given by the angles of the polygonal design.he postoperative refractive results of this study (meanplusmn SD refractive astigmatism of 1.9 � 1.2 D at 6onths) compares favorably with that reported in larger

eries using conventional PK laser-assisted22,26–28 andechanical trephination29,30 techniques. The accurate fit

f donor and recipient was confirmed in our study bycanning electron microscopy (Figure 2). Also, the safetyf the procedure, evaluated by postoperative endothelialell density, was similar to that of previous studies usingonventional PK.31,32

We found that decagonal PK performed with femtosec-nd laser to be an easy, safe, and effective means tomprove postkeratoplasty outcomes. Polygonal trephina-ion for PK provides an accurate positioning and an easieruturing of the graft in the recipient bed by reducingotational slippage of the graft. The potential advantagesf this new pattern compared with circular keratoplastyay include an enhancement of visual results and recovery

imes. However, longer follow-up and comparative studiesre needed to provide more confident estimates of astig-atism reduction proportions for each surgical method.ubsequently, these studies could seek other means for

mproving visual outcomes, such as an optimal number of

ides of the decagonal PK.

UBLICATION OF THIS ARTICLE WAS SUPPORTED IN PART BY THE DEPARTMENTAL COUNCIL OF “BOUCHES-DU RHONE” (CG13,arseille, France). The authors indicate no financial conflict of interest. Involved in Design of study (C.B., H.P., L.H.); Conduct of study (C.B., L.H.,.P.); Data collection (C.B.); Analysis and interpretation of data (L.H., F.M., C.B.); Statistical expertise (J.C.); Writing the article (L.H., C.B.); andritical revision of the article (H.P., B.R., J.C.). Approval from the Institutional Review Board, Marseille, France, was obtained. The study was

onducted with institutional approval and in accordance with the Declaration of Helsinki. All patients signed informed consent statements. The authorshank Joël Courageot, Department of Electronic Microscopy, Faculty of Medicine, Aix-Marseille University, for his technical support in scanninglectron microscopy specimen preparation and imaging.

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OPHTHALMOLOGY JANUARY 2011