Download Modified Femtosecond Laser–Assisted Sutureless Anterior Lamellar

TECHNIQUES
Modified Femtosecond Laser–Assisted Sutureless Anterior
Lamellar Keratoplasty
Gustavo Bonfadini, MD,*† Hamilton Moreira, MD, PhD,‡§ Albert S. Jun, MD, PhD,*
Mauro Campos, MD, PhD,† Eun Chul Kim, MD, PhD,*¶ Eduardo Arana, MD,‡ Márcio Zapparoli, MD,‡
Jurandir M. Ribas Filho, MD, PhD,§ and Peter J. McDonnell, MD*
Abstract: A variation of the femtosecond laser–assisted sutureless
anterior lamellar keratoplasty technique using a femtosecond laser incision for surgical management of anterior corneal disease is described. Six
patients with corneal scars were treated with the laser to create a horizontal
lamellar bed interface in the cornea of the donor and recipient eyes, with
a manual partial-thickness vertical trephination to complete the excisions.
This technique allows matching of donor and host tissue dimensions with
precise tissue apposition and greater surface area for healing. No intraoperative adverse events were observed. One patient developed epithelial
ingrowth, requiring a successful surgical intervention.
Key Words: femtosecond anterior lamellar keratoplasty, femtosecond laser–assisted sutureless anterior lamellar keratoplasty, lamellar
keratoplasty, femtosecond laser, corneal transplant
(Cornea 2013;32:533–537)
L
amellar keratoplasty (LK) is a surgical technique used to
treat corneal pathologies affecting the corneal stroma. It is
an extraocular procedure, and it provides improved wound
strength postoperatively and rapid visual rehabilitation
with minimal risk of corneal allograft rejection and other
long-term complications compared with conventional fullthickness corneal transplantation.1
Lamellar dissection of the stroma can be performed by
a manual technique using a variety of instruments, including
Received for publication March 17, 2012; revision received July 25, 2012;
accepted August 9, 2012.
From the *Department of Ophthalmology, The Division of Cornea & Anterior
Segment, Wilmer Eye Institute, Johns Hopkins School of Medicine,
Baltimore, MD; †Department of Ophthalmology, Federal University of
São Paulo, Paulista School of Medicine, São Paulo, Brazil; ‡Department
of Ophthalmology, Hospital de Olhos do Paraná, Curitiba, Brazil;
§Department of Surgery, Evangelical University of Paraná, Curitiba,
Brazil; and ¶Department of Ophthalmology & Visual Science, College of
Medicine, Catholic University of Korea, Seoul, Korea.
Supported in part by an unrestricted grant to the Wilmer Eye Institute from
Research to Prevent Blindness, New York, NY.
Dr McDonnell has served as an advisory board member for Abbott Medical
Optics and Alcon Laboratories.
Supplemental digital content is available for this article. Direct URL citations
appear in the printed text and are provided in the HTML and PDF
versions of this article on the journal’s Web site (www.corneajrnl.com).
Reprints: Gustavo Bonfadini, Rua Figueiredo Magalhães N.394/701, Copacabana,
Rio de janeiro 22031-012, Brazil (e-mail: [email protected]).
Copyright © 2012 by Lippincott Williams & Wilkins
Cornea Volume 32, Number 4, April 2013
lamellar knives and dissectors. Traditionally, manual dissection techniques have resulted in suboptimal visual outcomes
because of interface haze and scarring, and the acceptance of
this technique has therefore been limited.
In recent years, the femtosecond laser has been used
successfully in a variety of corneal procedures, including the
preparation of laser in situ keratomileusis (LASIK) flaps, the
creation of channels for intracorneal rings, and the preparation
of donor and host tissue in anterior lamellar keratoplasty
(ALK).2–5 This last application is ideally suited for ALK.
A newer approach to anterior corneal disease has been the
use of the 30-kHz IntraLase FS laser (AMO, Irvine, CA) to
assist in sutureless ALK (FALK), which was first described in
2008 by Yoo et al.4,5
Our report describes the use of a different laser (Ziemer
Ophthalmic Systems AG, Port, Switzerland) to perform FALK
in patients with anterior corneal scarring. This report also
describes the use of this technique with 2 different dissection
depths: midstromal (.250 mm of posterior residual corneal bed
thickness) and pre-Descemet (approximately 50 mm of posterior residual corneal bed thickness).
SURGICAL TECHNIQUE
The surgical procedures were performed at Hospital de
Olhos do Paraná, Curitiba, Brazil, and approved by the ethics
committee. All the tenets of Declaration of Helsinki were
followed. Six consecutive patients (4 men, 2 women) aged
41 to 67 years with anterior corneal scars were enrolled for
the series. Written informed consent was obtained in all cases.
All procedures were performed under topical anesthesia.
Anterior segment optical coherence tomography (RTVue-100;
Optovue, Fremont, CA) was used preoperatively in all patients
to measure the depth of the corneal opacity and the central and
peripheral thicknesses of the recipient cornea (Fig. 1).
Visual loss from acquired corneal opacifications can be
because of irregular astigmatism and/or the corneal opacity
itself. To rule out irregular astigmatism as a cause of visual loss,
a rigid gas-permeable contact lens refraction was performed
before recommending LK. Corneal opacity contributed significantly to the loss of visual acuity in all cases.
The 6 patients (Tables 1 and 2) underwent treatment with
a 1000-kHz FEMTO LDV laser (Ziemer Ophthalmic Systems
AG), creating a horizontal lamellar bed interface in the cornea
of the donor and recipient eyes. No sutures were used in all 6
FALK procedures of the study. Patients 1, 2, and 3 were treated
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Bonfadini et al
FIGURE 1. Anterior segment optical coherence tomography
for corneal evaluation in patient 1 (A) preoperatively and (B) 2
months after FALK, showing some residual corneal scarring.
with the laser programmed to leave at least 250 mm of posterior
residual corneal bed thickness. Patients 4, 5, and 6 underwent
FALK with the laser programmed to leave at least 50 mm
posterior residual corneal bed thickness overlying the thinnest
part of the cornea (Tables 1 and 2). Criteria for deeper excisions included: (1) increased depth of opacity (Table 2) and (2)
absence of patient or family history of corneal ectasia.
To create the donor grafts, corneoscleral donor tissue was
removed from storage solution (Optisol-GS; Bausch & Lomb
Surgical, Irvine, CA) and mounted on an artificial anterior
chamber (LDV; Ziemer Ophthalmic Systems AG). The femtosecond laser keratoplasty software was programmed as follows:
donor lenticule thickness of 280 to 500 mm, applanation 8.5 to
9.5 mm, vacuum value 750 mbar, total cut time for patients
ranged from 55 to 76 seconds, total cut time in donor tissue
ranged from 36 to 45 seconds, applanation time 57 to 63
seconds in patients, and applanation time ranged from 57 to
63 seconds in the donors. For patients, we programmed 2.5 to
3.5 mm/s velocity of the stroma (adjusted according to the
severity of the corneal scar) and 30 mm/s velocity of the border.
For donors, we used 4.0 mm/s velocity of the stroma and
30 mm/s velocity of the border.
Depending on the donor tissue quality and edema, 10%
to 20% additional thickness was added to the donor lenticule to
adjust for donor tissue swelling. Vertical incision was made in
the donor and recipient tissues using a manually held 8.0-mm
trephine blade (Katena Products, Denville, NJ). The host
corneal button and the donor graft were gently separated from
the underlying stroma using a Sinskey hook and a spatula, and
the donor graft was immediately placed on the recipient
residual corneal stromal bed. The vertical incision was dried
with methylcellulose sponges and the flap was checked for
adhesion by depressing the peripheral host cornea and ensuring
that the resulting indentation radiated into the lenticule (similar
to checking for flap adhesion after LASIK with the striae test).
A bandage contact lens was fitted over the cornea and left in
place for 1 week.
Patients were placed on a topical moxifloxacin hydrochloride 0.5% ophthalmic solution (Vigamox; Alcon Laboratories,
Fort Worth, TX) 4 times daily for 1 week. Topical prednisolone
acetate 1.0% eye drops (Pred-Forte; Allergan, Irvine, CA) were
initially used 4 times daily and slowly tapered over 4 months.
Additionally, we used 0.1% nepafenac ophthalmic solution
(Nevanac; Alcon Laboratories) 4 times daily for 1 week. All
patients were treated with artificial tears (Systane Ultra; Alcon
Laboratories) after surgery to ensure adequate lubrication of the
ocular surface. The follow-up visits for the patients were 1, 2,
and 4 weeks, 2, 4, and 6 months, and 1 year after FALK (Fig. 2).
RESULTS
The characteristics of patients included in the study are
summarized in Table 1. In this case series, no intraoperative
complications occurred. At 1 week postoperatively, all eyes
were white and quiet, the corneas were clear and reepithelialized, and intraocular pressures were normal.
Uncorrected visual acuity (UCVA) and best-corrected
visual acuity (BCVA) improved in all patients compared with
preoperative visual acuity, and all the eyes had clear grafts at
the 1-year follow-up (Video, Supplemental Digital Content,
http://links.lww.com/ICO/A81 and Table 2). The mean difference
between preoperative and postoperative UCVAs was a gain of 4.3
lines (range, 3–8 lines). BCVAs were improved in all eyes
compared with preoperative levels. The mean difference
between preoperative and postoperative BCVAs was a gain of
8.0 lines (range, 4–13 lines).
No intraoperative complications, graft rejection, or
infection were found in this series of patients at 1-year
follow-up. Patient 3 was noted to have epithelial ingrowth in
the graft–host interface 2 weeks after FALK (Fig. 3). The
epithelial ingrowth was debrided surgically, and the graft
TABLE 1. Patient Characteristics
Characteristic
Patient 1
Patient 2
Patient 3*
Patient 4†
Patient 5
Patient 6†
Demographics
Sex
Age, yr
Eye
Diagnostic
categories
Male
67
OD
Infectious
keratitis
Female
41
OS
Herpetic
disease
Female
43
OD
Keratoconjunctivitis
Male
45
OS
Infectious
keratitis
Male
47
OD
Postpterygium
excision
Male
60
OD
Infectious
keratitis
*Patient 3 has diabetic retinopathy. The patient had epithelial ingrowth. Surgical intervention to debride the ingrowth and suture the graft were performed.
†Patients 4 and 6 had previously diagnosed amblyopia.
OD, right eye; OS, left eye.
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Femtosecond Anterior Lamellar Keratoplasty
TABLE 2. Patient Outcomes
Characteristic
BCVA
Preoperative (logMAR)
4 mo postoperative (logMAR)
1 yr postoperative (logMAR)
UCVA
Preoperative (logMAR)
4 mo postoperative (logMAR)
1 yr postoperative (logMAR)
Refraction
Preoperative refraction, D
Patient 1
Patient 2
Patient 3*
Patient 4†
Patient 5
Patient 6†
1
0.18
0.10
1.3
0.18
0.18
1
0.54
0.48
1
0.7
0.7
1.3
0
0
1.3
0.7
0.7
1.3
0.7
0.7
1.3
1
1
1.3
1
1
1.3
1
1
1.6
0.6
0.6
1.3
1
1
S + 6.00
4 mo postoperative refraction, D
S21.50 C22.50
· 85 degrees
S + 4.00
1 yr postoperative refraction, D
S + 4.00
Defocus equivalent refraction
Preoperative defocus
equivalent refraction, D
4 mo defocus equivalent
refraction, D
1 yr defocus equivalent
refraction, D
Lines gained of BCVA from
preoperative BCVA
4 mo postoperative refraction, D
1 yr postoperative refraction, D
Corneal topography
Preoperative: K1
steep/K2 flat, D
4 mo postoperative: K1
steep/K2 flat, D
1 yr postoperative: K1
steep/K2 flat, D
1 yr postoperative:
topographic patterns
Optical coherence
tomography of the cornea
Preoperative corneal
thickness: scarring/
total cornea, mm
Patient posterior residual
corneal bed
thickness, mm
Postoperative corneal
thickness, mm
Clinical examination
Slit-lamp at 4 mo
Slit-lamp at 1 yr
S + 8.00 C21.00
· 30 degrees
S + 7.00 C21.50
· 50 degrees
S28.00 C25.00
· 50 degrees
S + 6.00 C22.00
· 150 degrees
S + 5.50 C22.00
· 170 degrees
S + 2.50 C25.00
· 50 degrees
S + 4.00 C22.00
· 140 degrees
S + 3.50 C22.25
· 130 degrees
S21.00 C23.00
· 30 degrees
S22.00 C21.00
· 40 degrees
S22.00 C21.25
· 52 degrees
S21.00 C24,00
· 35 degrees
S + 3.00 C22.00
· 150 degrees
S + 2.00 C21.00
· 130 degrees
4
6
13
2.5
4
5
4
8
6
4
3
3
4
7
5.5
3.5
3.25
2
8
9
11
11
4
5
6
6
13
13
6
6
43.6/40.9
42.08/41.82
48.60/44.11
42.80/38.74
43.52/40.15
46.82/42.97
39.45/39.32
40.85/39.56
43.92/41.58
40.30/38.58
44.29/43.37
42.28/40.13
39.65/39.46
41.56/39.75
43.66/41.21
40.02/38.40
44.38/43.52
41.47/40.02
Regular
astigmatism
Regular
astigmatism
Irregular
astigmatism
Regular
astigmatism
Regular
astigmatism
Regular
astigmatism
274/463
236/525
227/539
347/554
414/545
393/537
250
250
250
;50
;50
;50
542
491
596
541
504
546
Clear graft
Clear graft
Clear graft
Clear graft
Sutures with haze
and wrinkling
at the interface
No sutures with
mild haze
Clear graft
Clear graft
Clear graft
Clear graft
Clear graft
Clear graft
*Patient No. 3 has diabetic retinopathy. The patient had epithelial ingrowth. Surgical intervention to debride the ingrowth and suture the graft was performed.
†Patient Nos. 4 and 6 had previously diagnosed amblyopia.
D, diopters; K, keratometry; logMAR, logarithm of the minimum angle of resolution; OD, right eye; OS, left eye; S, spherical; C, cylinder.
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FIGURE 2. A, Corneal slit-lamp photograph of patient 1, a
67-year-old man with a paracentral scar and BCVA of 20/200.
B, Two months after FALK, with restoration of corneal clarity
and improvement in BCVA to 20/30.
was sutured into position. Topical steroids were tapered
slowly until removal of the last suture 11 months after the
original procedure. At 1-year follow-up, no recurrence of the
epithelial ingrowth was noted.
At 1-year follow-up, 5 of 6 patients showed regular
astigmatism, and 1 patient showed irregular astigmatism
(patient 3, Table 2). None of the patients showed topographic
or clinical evidence of ectasia.
DISCUSSION
The use of the femtosecond laser to produce corneal
incisions has improved the precision of lamellar corneal
transplantation surgery. Although mechanical microkeratomes have been used for this purpose, femtosecond flaps
have stronger adhesion than microkeratome flaps,6,7 and this
may provide additional graft stability during the early postoperative period. The fit between donor and recipient lenticules in our series was highly reproducible, allowing all
patients to have sutureless ALK completed without difficulty.
Our series is unique, to our knowledge, in that we had 2
depths of femtosecond laser lamellar excision. Patients 1, 2,
and 3 were left with at least 250 mm of posterior residual
corneal bed thickness, and patients 4, 5, and 6 were left with
50 mm of posterior residual corneal bed thickness based on
anterior segment optical coherence tomography measurements on the recipient eye (Table 2).
Our rationale for not suturing the grafts for the deeper
FALK dissections in patients 4, 5, and 6 included: (1)
avoidance of suture-related complications, (2) relative stability
of graft placement in femtosecond laser–prepared tissue as in
a femtosecond laser–prepared LASIK flap and in LK reported
by Yoo et al,4,5 and (3) reasonable, though not full, tectonic
stability of a 50-mm posterior stromal layer. Although point 3
may be particularly debatable, patients with areas of chronic,
severe corneal thinning with comparable levels of stromal support, that is, approximately 100 mm total corneal thickness
including overlying intact epithelium, can be managed conservatively without surgery.
Ectasia is a substantial concern in LK as removal of
tissue undoubtedly reduces mechanical strength of the cornea.
We did not observe any cases of ectasia in our series at 1-year
follow-up. However, it is clear that ectasia can occur later
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FIGURE 3. A, Corneal slit-lamp photograph of patient 3, a
43-year-old woman with a superior paracentral scar and BCVA
of 20/200. B, Two weeks after FALK, epithelial ingrowth was
found at the interface. C, One month after second surgical
intervention. Lifting of the anterior lamellar graft to debride
the epithelial ingrowth together and corneal suturing were
successfully done, with restoration of corneal clarity and
improvement in BCVA to 20/70.
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than 1 year after surgery, and thus, we cannot rule out this
long-term possibility in our patients. Posterior stromal bed
thickness of 250 mm is an acknowledged guideline
to minimize risk of ectasia in LASIK. However, before the
acceptance of this value, LASIK cases were performed, which
resulted in less posterior stromal bed thickness, and ectasia
remains relatively rare even among these cases. In addition,
deep ALK is routinely performed, even in naturally occurring
ectatic cornea, for example, keratoconus, with less than 50 mm
posterior stromal bed thickness, and ectasia in these grafts is
also rare. Although it has been proposed that the healing
response along graft sutures provides the tectonic strength
needed to prevent ectasia in these grafts,8 this topic has not
been studied extensively. Thus, long-term follow-up of a larger
number of patients in future studies could provide more information about the likelihood of ectasia in patients undergoing
FALK and whether sutures can reduce this risk.
Overall, we feel that this pilot series shows encouraging
results for our described technique. It also suggests a variety
of issues for further evaluation. From a safety perspective, the
long-term risk of ectasia should be determined. As well, the
use of sutures, either for potentially increased tectonic strength
in deeper dissections as suggested by Abdelkader et al8 or in
preventing complications from pathologic epithelial healing as
in our diabetic patient 3, deserves study. However, the potential to avoid suturing these grafts has advantages, including
earlier visual rehabilitation and potentially less induced
astigmatism.4,5
FALK clearly has advantages over traditional penetrating
keratoplasty (PK) or LK techniques. These include the ability
to use topical anesthesia and a much faster procedure. Our
results indicate that in some cases sutures are not required,
although this will require further validation. In addition,
compared with PK, the procedure is extraocular with no
concern for endothelial graft rejection. Compared with previous reports of FALK, we feel that our technique using deeper
dissections has an advantage in allowing better rehabilitation of
deeper scars and avoiding the need for additional procedures,
such as phototherapeutic keratectomy described by Yoo et al.4,5
As mentioned above, although ectasia is a concern in these
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Femtosecond Anterior Lamellar Keratoplasty
cases, suturing may provide additional tectonic support, and
even still FALK may be worth considering compared with the
alternative that would likely be manual/big bubble deep ALK
or PK.
In summary, 1-year follow-up results of our “modified” FALK technique indicate that the method is effective
in the removal of corneal scars with substantial improvement in UCVA and BCVA. Although our follow-up time
is limited, we did not observe any cases of corneal ectasia
even for deeper dissections. We did observe one postoperative complication of epithelial ingrowth, which resolved
with further treatment. These preliminary results suggest
that the use of a manual partial-thickness vertical trephination in combination with femtosecond laser may be an
improvement over conventional ALK and PK. Larger studies will be needed to validate our findings and to further
address questions, such the need for sutures and long-term
outcomes and complications.
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