Transcript Slide 1

Femtosecond Laser-assisted
Penetrating Keratoplasty
Mohammad Zare MD
Professor of Ophthalmology
Labbafinejad Medical Center
Shaheed beheshti Medical
University
18-10-2012
One hundred years after the first successful
penetrating keratoplasty (PK) by Zirm in
1905, corneal transplantation has become
the most commonly performed transplant
in the world.
The invention of femtosecond laser
technology has allowed great advances in
the field of penetrating keratoplasty (PKP).
Combining advanced LASIK technology
with current transplantation concepts
has taken cornea grafting to the next
plane.
In penetrating keratoplasty, misalignment of the
anterior surface of the donor and host, are
major sources of optical distortion and limit
visual outcomes due to:
1- Rotational misalignment, where the
tissue is not precisely distributed,
2- excess and uneven suture tension,
3- postoperative slow and uneven
wound healing,
Femtosecond laser (IntraLase)
1- Provides a safe and predictable means of
performing a customised cut in PK procedures,
2- Is a very sophisticated device that allows for
greater precision to match the exact shape of
the removed and donated tissue segments.
3- Any cut configuration and angulation can be
chosen,
4- The cut quality is excellent
5- The prepared donor transplant nestles
perfectly in the recipient eye.
5- Other theoretical benefits include:
 greater biomechanical stability,
 better wound healing,
 reduction in induced astigmatism
 faster visual rehabilitation.
This is usually not the case when we
perform traditional penetrating
keratoplasty with a cylindrical trephine.
Evaluation and Surgery
 proper patient selection criteria should be met.
 Potential candidates should be suitable for full-thickness penetrating
keratoplasty.
 Relative contraindication
 severe peripheral neovascularization and scarring in some cases.
 contraindication
 Previous glaucoma filtering surgery in the form of an active bleb or
aqueous drainage device
 Patients with very narrow palpebral fissures should be carefully
evaluated preoperatively to make sure that the suction ring can be
fitted and suction maintained.
 During preoperative evaluation specific attention is paid to corneal
diameter, especially vertical, to determine the required graft
diameter.
 A preoperative pachymetry map is performed to adequately assess
and program depth settings for the femtosecond laser incision.
 Informed patient consent is mandatory.
• Donor corneas can be cut by the femtosecond laser
with preprogrammed parameters set by the surgeon.
• This is done with the donor tissue mounted on an
artificial anterior chamber or alternatively 'precut' with
the same parameters by the eyebank.
There are numerous patterns that can be programmed for
femtosecond laserassisted PKP.
• Figure 2 Various shapes used in laser assisted keratoplasty. Standard
cut (A) Top hat (B) Mushroom (C) Zig-zag (D) Christmas tree (E)
'zig-zag' incision
Max: 9mm
320µm
0.50 mm
70µ a bridge of uncut corneal tissue is left
 That side-cut bridges are stronger than lamellar bridges
Identical parameters are used for the donor
cornea and the host incision.
Evaluation and Surgery
• Generally, for the laser cut, topical anesthesia
is used.
• It is important to ensure proper centration of
the patient interface to allow for centration of
the graft.
•
• After the femtosecond laser incision is performed,
 the eye is treated with prophylactic antibiotic drops and
shielded.
 The patient is then transferred to the operating suite
where either retrobulbar or general anesthesia is
administered.
 The host corneal button is separated by blunt dissection
with a Sinskey hook to reveal the incisions made by the
laser.
 In most cases the laser incisions separate cleanly.
 In areas of dense corneal scarring, limited sharp dissection
with a surgical blade or scissors may be required.
 After the 360-degree blunt dissection of the laser incision,
the anterior chamber is entered with a blade and the
posterior cut is completed using corneal scissors.
 The donor cornea is then sutured into place using
whatever suturing style the surgeon prefers
• Top hat shaped corneal graft. IntraLase
software used.
Table 1: Corneal top hat parameters of host and donor corneas.
Recipient cornea
Donor cornea
Lamellar depth
300 microns
300 microns
Outer diameter
9.1 mm
9.3mm
Inner diameter
6.5 mm
7.6mm
250 microns, diameter
7.5mm
330 microns, 7.7mm
270 microns, diameter
9.0mm
270 microns, 9.2mm
Anterior side cut posterior
depth
Posterior side cut anterior
depth
Laser Assisted Keratoplasty: Key Points
•When to consider laser assisted keratoplasty?
•Any patient who requires a full-thickness corneal transplant
•Patients in whom a faster time to visual rehabilitation is desirable
•Consider the top hat shape for patients with underlying endothelial pathology, such as Fuchs
•Traditional PKP
•Lengthy visual rehabilitation
•Potential wound leakage due to shape of traditional corneal button
•Increased suture tension in order to approximate donor and recipient wound edges
•High incidence of irregular astigmatism post-operatively
•Increased length of time to suture removal due to decreased wound surface area and
increased healing time
•Decreased endothelial cell counts due to a lesser number of transplanted endothelial
cells as compared with top hat PKP
Advantages of Laser Assisted Keratoplasty over
traditional PK
•Increased wound surface area leads to faster healing and
decreased time to suture removal
•Decreased visual rehabilitation time
•A variety of precise, complex corneal cuts and shapes can be
made
•Increased endothelial cell counts due to greater surface area
of transplanted endothelium in top hat shape
•Greater wound strength and watertight seal
•Decreased wound dehiscence
•Better fit of donor cornea as compared with manual dissection
•Potential for decreased post-op astigmatism, however further
studies must be conducted
Am J Ophthalmol. 2007 May;143(5):737-742. Epub 2007 Mar 19.
The use of the femtosecond laser in penetrating
keratoplasty.
Buratto L, Böhm E.
SourceCentro Ambrosiano di Microchirurgia Oculare (C.A.M.O. S.p.A.), Milan, Italy. [email protected]
Abstract
PURPOSE: To evaluate a new technique for penetrating keratoplasty (PK) with the use of a new software algorithm for a
femtosecond laser that is designed to create penetrating cuts for PK in the treatment of a number of corneal diseases.
DESIGN: Prospective, interventional case series.
METHODS: All eyes were treated at the Ospedale Civile di Mestre, Umberto, Italy. Seven eyes of seven patients underwent
surgery for PK using a 15-kHz femtosecond laser (IntraLase, Irvine, California, USA) and a new software specifically
developed for corneal surgery. Of the seven patients, five were keratoconus patients and two had bullous keratopathy.
New software was used to create penetrating cuts in a top hat or mushroom configuration. After surgery, all patients
were evaluated with pachymetry, corneal topography, refraction, intraocular pressure measurement, and corneal optical
coherence tomography (Visante; Carl Zeiss, Oberkochen, Germany.)
RESULTS: On postoperative day one, all seven eyes had nearly clear corneas with a good graft of the donor corneas to the
patients' corneas. At three months, all eyes had clear corneas with good endothelial cell counts and quiet anterior
chambers. Normal corneal thickness was achieved in each case. At the three-month visit, suture removal was performed
in five eyes to adjust for astigmatism.
CONCLUSIONS: Although this is a small number of eyes, early indications are that the use
of the new IntraLase software for corneal surgery creates a more favorable
environment for PK as a result of a better fit of the donor cornea and a quicker visual
recovery for patients
American Journal of Ophthalmology, Volume 145, Issue 5, May 2008, Pages 772–774.e2
Original article
Outcomes of Femtosecond Laser–Assisted Penetrating Keratoplasty
Yong M. Pora, b, Jacob Y. Chuan Chenga, b, Anand Parthasarathya, b, Jodhbir S. Mehtaa, b, Donald T.H. Tana, b, c, ,
a Singapore National Eye Centre, Singapore
b Singapore Eye Research Institute, Singapore
c Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
Purpose
To evaluate outcomes from the use of a femtosecond laser to trephine both donor and recipient corneas during
penetrating keratoplasty (PK).
Design
Prospective interventional case series.
Methods
Patients were recruited from the cornea clinic of the Singapore National Eye Centre. We used a 10-kHz Femtec
(20/10 Perfect Vision, Heidelberg, Germany) femtosecond laser to perform trephination of the donor cornea on
an artificial anterior chamber, followed by trephination of the recipient cornea. Trephination cuts were straight
and performed 90 degrees to the corneal surface. Tissue bridges were bluntly separated with a Barrett phaco
chopper. The donor button was then sutured to the recipient with double continuous sutures, or interrupted
sutures if significant host corneal vascularization was present. Postoperatively, visual acuity, refraction,
intraocular pressures, and optical coherence tomography (Visante; Carl Zeiss, Jena, Germany) were evaluated.
Results
Eight eyes of eight patients underwent PK for conditions ranging from bullous keratopathy to corneal scarring from
herpetic stromal keratitis. Patients were followed up for a mean of 9.5 months. Best-corrected visual acuities of
patients with no ocular comorbidity ranged from 20/20 to 20/80. Mean cylindrical refractive error at last review
was 2.56 diopters [D] (range, 0.50 to 4.00 D). Tissue bridges were bluntly dissected except for one case that
required scissors completion of trephination. No complications were encountered related to use of the Femtec
laser.
Conclusion
The Femtec laser reliably trephines both donor and recipient corneas for PK, with good visual outcomes and
relatively low degrees of astigmatism.
Am J Ophthalmol. 2008 Jul;146(1):50-55. Epub 2008 Apr 24.
Short-term results of penetrating keratoplasty performed with the Femtec femtosecond
laser.
Hoffart L, Proust H, Matonti F, Ridings B, Conrath J.
SourceDepartment of Ophthalmology, Hopital de la Timone, 264 rue Saint-Pierre, Marseille cedex 05, France.
[email protected]
Abstract
PURPOSE: To evaluate the use of the Femtec femtosecond (fs) laser for penetrating keratoplasty (PK) in the treatment of
corneal diseases.
DESIGN: Prospective, nonrandomized clinical study.
METHODS: Nine eyes of nine patients underwent surgery for PK. Five had pseudophakic bullous keratopathy, three had
Fuchs dystrophy, and one presented in a keratoconus patient. A Femtec (20/10 PerfectVision; GmbH, Heidelberg,
Germany) fs laser was used to create penetrating cuts on donor and recipient corneas. All patients were evaluated for
uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), pachymetry, topography, and
endothelial cell density (ECD). Scanning electron microscopy (SEM) was performed on corneal tissue after surgery.
RESULTS: All eyes were treated successfully without intraoperative complications. The mean follow-up was 6 +/- 3 months.
At the last postoperative examination mean BSCVA was 20/69 and there was a significant improvement (P = .08) in
both UCVA and BSCVA. Mean astigmatism was 2.9 +/- 1.2 diopters. Mean ECD was 1194 +/- 465 cells/mm(2) with a
mean cell loss after surgery of 49.8% +/- 19.8%. SEM displayed smooth rectilinear cut margins and minor remaining
tissue bridges. One patient presented a retinal detachment three months after surgery that was successfully treated
and two subjects showed an allograft rejection.
CONCLUSION: Use of the Femtec fs laser was effective and safe to perform PK. Short-term visual
results and refractive results are analogous to conventional PK or other fs laser-assisted PK
studies. Longer-term follow-up of additional cases is necessary to precisely quantify the
endothelial cell loss after fs surgery.
PMID:18439558[PubMed - indexed for MEDLINE
Br J Ophthalmol. 2009 Jan;93(1):73-8. Epub 2008 Oct 16.
Femtosecond laser versus manual dissection for top hat
penetrating keratoplasty.
Bahar I, Kaiserman I, Lange AP, Levinger E, Sansanayudh W, Singal N, Slomovic AR, Rootman DS.
SourceDepartment of Ophthalmology, Toronto Western Hospital, 399 Bathurst Street, Ontario, Canada.
[email protected]
Abstract
AIM: To compare the outcomes of IntraLase-enabled top hat penetrating keratoplasty (IEK) versus
retrospective results of manual top hat penetrating keratoplasty (TH-PKP) and conventional PKP.
Patients/methods: This non-randomised prospective study included 94 eyes: 23 eyes underwent
IEK, 36 TH-PKP and 35 conventional PKP. Preoperative and postoperative manifest refraction,
uncorrected and best-spectacle corrected visual acuity (BSCVA), high-order ocular aberrations
(HOA), endothelial cell counts and complications were analysed.
RESULTS: At 12 months of follow-up, the mean log MAR BSCVA was 0.32 (SD 0.31) in the IEK group, 0.53
(0.36) in the TH PKP group (p = 0.03) and 0.39 (0.30) in the conventional PKP group (p = 0.4). The
mean spherical equivalent was similar between the groups and was less than -2.2 dioptres. The
mean cylinder was similar in the IEK and conventional PKP group (3.6 (1.9) dioptres and 4.1 (1.8)
dioptres, respectively), and was significantly lower than the TH-PKP group (5.1 (3.2) dioptres, p =
0.04). The complications rate and high-order ocular aberrations were similar between the three
groups studied. The mean endothelial cell loss was significantly lower at 12 months of follow-up in
the IEK and the TH-PKP groups versus conventional PKP (32.4% and 22.3% vs 40.8%, respectively) (p
= 0.05). The mean time to suture removal was 4.1 (1.2) months in the IEK group and 3.9 (1.5)
months in the TH-PKP group versus 9.7 (1.1) months in the conventional PKP group (p<0.0001.)
CONCLUSIONS: IEK is a safe and stable procedure. It results in higher endothelial
counts and faster suture removal in comparison with the conventional PKP, and
has less astigmatism and better BSCVA in comparison with the manual TH-PKP
Cornea. 2009 Aug;28(7):795-800.
Top-hat shaped corneal trephination for penetrating keratoplasty using the
femtosecond laser: a histomorphological study.
Kook D, Derhartunian V, Bug R, Kohnen T.
Source; Department of Ophthalmology, Johann Wolfgang Goethe University, 60590 Frankfurt am Main, Germany.
Abstract
PURPOSE:
To evaluate a novel technique for penetrating keratoplasty (PK) with the use of a new software algorithm for the
femtosecond laser, designed to create penetrating cuts in a top hat configuration.
DESIGN:
Consecutive histomorphological case series.
PATIENTS AND METHODS:
Twelve eyes of 12 patients underwent penetrating keratoplasty by means of a 60-kHz femtosecond laser (IntraLase, Irvine,
California) with a software specifically developed for corneal surgery. Of the 12 patients, the reason for keratoplasty
was keratoconus in 4 patients, bullous keratopathy in 6 patients, keratotorus in 1 patient, and status post chemical
burn in 1 patient. A new software was used to create penetrating cuts in a top-hat-shaped configuration. In all cases,
cutting parameters were identical in all donor and corresponding host corneas: 7.0 mm diameter of the anterior side
cut, 8.5-8.7 mm diameter of the posterior side cut, and a depth of 300 microm for the lamellar cut. In all cases, a
complete penetrating cut with the laser in the host cornea was not intended intraoperatively. Complete penetration
was performed subsequently and manually with a diamond knife because of logistic conditions. Trephined
corneoscleral rings and button corneas were analyzed macroscopically and histologically to determine cut quality.
RESULTS:
All procedures were performed without any complications. With application of appropriate combinations of pulse energy
and spacing, trephination took less than 200 seconds. Macroscopic examination and histology of donor and recipient
specimens showed a straight, smooth cut with perpendicular edges in all donor buttons. No corneal edema and no
visible damage to the keratocyte nuclei were found. At the region of manual dissection, a small stromal tissue-tag
was present in parts of the circumference in all donor buttons. No evidence of any cut complication was noted.
CONCLUSIONS:
Top-hat-shaped penetrating keratoplasty using the IntraLase femtosecond laser enables a quick and
sufficient trephination of both human donor and host corneas. It creates favorable
histomorphological results with regard to cut quality of the donor and host corneas.
PMID: 19574905 [PubMed - indexed for MEDLINE]
Graefe's Archive for Clinical and Experimental Ophthalmology
2012, DOI: 10.1007/s00417-012-2054-0
Cornea
Clinical results of 123 femtosecond laser-assisted
penetrating keratoplasties
Florian Birnbaum, Antonia Wiggermann, Philip C. Maier, Daniel Böhringer and Thomas Reinhard
Abstract
Background
Postoperative astigmatism following penetrating keratoplasty is a major problem after corneal
transplantation. The main goal of new trephination techniques such as femtosecond laser or
excimer-laser trephination is to improve refractive and visual outcomes. The femtosecond laser
technique makes profiled corneal trephinations such as the top hat or mushroom profile possible.
We present the postoperative outcome of femtosecond laser-assisted penetrating keratoplasties.
Methods
We performed 123 femtosecond laser-assisted penetrating keratoplasties in 119 patients. The main
outcome measures were intraoperative specifics, astigmatism, and irregularity in Orbscan corneal
topography, as well as the occurrence of immune reactions and side-effects.
Results
All sutures have been removed in 49 of these 123 eyes. Their mean follow-up was 13.9 ± 4.5 months.
Time to complete suture removal (n = 49) was 12.0 ± 3.7 months in the mushroom group and
9.8 ± 2.1 months in the top hat group. Mean astigmatism in Orbscan topography was 6.4 ± 3.0
diopters in the mushroom and 5.8 ± 4.6 diopters in the top hat group (all sutures out).
Conclusions
Femtosecond laser-assisted penetrating keratoplasty is a safe surgical technique. Due to the steps in
profiled trephinations, the wound area is larger and theoretically the wound healing is, thus, faster
and more stable. Complete suture removal is possible at an earlier time point compared to
conventional penetrating keratoplasty. However, refractive results are not superior to those
following conventional trephination.
Invest Ophthalmol Vis Sci. 2012 May 4;53(6):2571-9. Print 2012 May.
Manual suction versus femtosecond laser trephination for penetrating keratoplasty:
intraocular pressure, endothelial cell damage, incision geometry, and wound
healing responses.
Angunawela RI, Riau A, Chaurasia SS, Tan DT, Mehta JS.
Source; Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore.
Abstract
PURPOSE:
To measure real-time intraocular pressure (IOP) during trephination with a manual suction trephine (MST) and
the femtosecond laser (FSL), and to assess endothelial cell damage, incision geometry, and wound healing
response with these procedures.
METHODS:
IOP was monitored with an intracameral sensor. Eight rabbits underwent manual suction trephination. Eight
rabbits had FSL trephination (FSL-T). Slit lamp photography, confocal microscopy, and anterior segment
optical coherence tomography (AS-OCT) were performed at baseline and postoperatively. Animals were
sacrificed at 4 hours and 3 days. Tissue was examined with scanning electron microscopy (SEM) and
immunohistochemistry for an array of wound-healing markers. Separately, 6 human corneas had MST (3)
and FSL-T (3). Incision geometry was imaged with high resolution Optovue AS-OCT.
RESULTS:
The average IOP during MST and FSL-T was similar (37 mm Hg). There was wider IOP fluctuation during the MST
cutting phase (60 mm Hg maximum). There were 1-2 rows of endothelial loss on either side of the incision
for FSL-T and 2-5 rows deep for MST. Immune cell responses at 4 hours (CD11b) were comparable, greater
apoptosis with FSL-T (TUNEL) occurred at 4 hours, and there was increased keratocyte proliferation at 3
days (Ki67) with FSL-T. There was significantly greater undercutting of the cornea with MST (46.86 degrees
versus 16.72 degrees).
CONCLUSIONS:
There is more IOP variation during MST. Average IOP is 37 mm Hg for both
techniques. More endothelial damage and undercutting of the cornea
occurs with MST. The wound healing response to FSL-T appears greater at
3 days.
PMID: 22427557 [PubMed - indexed for MEDLINE]
Br J Ophthalmol doi:10.1136/bjophthalmol-2012-301662
Clinical science
Penetrating keratoplasty using femtosecond laser-enabled keratoplasty with zig-zag
incisions versus a mechanical trephine in patients with keratoconus
Ronald N Gaster, Oanna Dumitrascu, Yaron S Rabinowitz
+ Author Affiliations
Cornea Eye Institute, Beverly Hills, California, USA
Correspondence to Dr Yaron Rabinowitz, Cornea Eye Institute, Cedars Sinai, 50 N. La Cienega Blvd., Suite 340, Beverly Hills, CA
90211, USA; [email protected]
Contributors All authors contributed to the writing, editing and data collection for this paper.
Accepted 9 June 2012
Published Online First 11 July 2012
Abstract
Background/aims This paper will compare the visual outcomes of two different penetrating keratoplasty
(PKP) techniques in patients with keratoconus. It is a retrospective comparative surgical case series of 116
keratoconus patients (137 eyes) who had PKP at the Cornea Eye Institute, Beverly Hills, California, USA.
Methods 56 keratoconus patients (66 eyes) underwent femtosecond laser-enabled keratoplasty (FLEK) with a
zig-zag incision configuration. Their visual parameters were compared with those of 60 patients (71 eyes)
who had traditional blade mechanical trephination PKP. The range of follow-up was between 3 and
6 months. The main outcome measures included uncorrected visual acuity and best spectacle-corrected
visual acuity (BSCVA), manifest refractive spherical equivalent and topographically determined
astigmatism.
Results BSCVA was significantly better as early as 3 months postoperatively (p=0.001) in the FLEK group.
Visual recovery to 20/40 after 3 months was significantly better in the FLEK group (p<0.001). Topographic
astigmatism was lower in the FLEK group, but the difference between the two groups reached significance
only at 3 months of follow-up (p=0.001). Postoperative complications noted were not different between
the two groups.
Conclusions Faster visual recovery and better long-term outcomes were
observed in keratoconus patients who had FLEK compared with those who
had the mechanical PKP procedure with 6 months of postoperative followup.
Fibrin Sealant and Femtosecond Laser Assisted Keratoplasty: Initial Results
Tatiana MB Prazeres1*, Elissandro MS Lindoso1, Leon Grupenmacher2 and Luciene B Sousa3
1Clinical Fellow, Cornea and External Diseases Division, Department of Ophthalmology, Sorocaba Eye Bank, Sorocaba, Sao
Paulo, Brazil
2Attending Physician, Department of Ophthalmology, Sorocaba Eye Bank, Sorocaba, Sao Paulo, Brazil
3Head Professor of the Department of Ophthalmology, Sorocaba Eye Bank, Sorocaba, Sao Paulo, Brazil
Abstract
Purpose: To evaluate whether the use of a sealant combined with interrupted suture would provide
better visual outcomes and better post-operative recovery to keratoconic patients compared to
interrupt and running sutures without the use of sealants using femtosecond laser assisted keratoplasty.
Methods: A prospective, randomized study of 12 patients (12 eyes) with keratoconus was conducted,
randomized into two treatment groups. The no glue group (6 eyes) underwent penetrated keratoplasty
(PK) with femtosecond laser assisted keratoplasty shaped (mushroom) and combined suture (8
interrupted suture and 8 running sutures) while the glue group (6 eyes) underwent the same procedure
but their incisions were closed with 8 interrupted sutures and sealant.
Results: The no glue group had a mean BCVA of 0.2 (LogMar). The glue group had a mean BCVA of 0.3
(LogMar). p=0.028 Transplants with glue were well positioned showing good healing but presented
more inflammation in the first week post-surgery. Regarding refractive outcomes, there was no
difference between the groups.
Conclusions: There were no statistical difference between the two groups
regarding BCVA and refractive errors. The use of sealants produced more
inflammation. Further studies with a larger number of patients and longer
follow up would be needed to confirm these findings.
*Corresponding author: Tatiana Prazeres MB, Rua Conselheiro Correa de
Menezes, n266, Apt 701, Salvador, Bahia, Brazil, Tel: 55-71-3334-3084/ 55-718799-3084; E-mail: [email protected]
Copyright: © 2012 Prazeres TMB, et al
Keywords: Fibrin sealant; Penetrating keratoplasty; Femtosecond laser; Interrupted sutures; Running sutures
Ophthalmology. 2009 Sep;116(9):1638-43. Epub 2009 Jul 31.
Comparison of penetrating keratoplasty performed with a femtosecond
laser zig-zag incision versus conventional blade trephination.
Farid M, Steinert RF, Gaster RN, Chamberlain W, Lin A.
Source
Department of Ophthalmology, The Gavin Herbert Eye Institute, University of California-Irvine, CA 92697, USA.
Abstract
PURPOSE:
To evaluate visual outcomes and astigmatism in patients who underwent penetrating keratoplasty (PK) with 2 different incision
techniques.
DESIGN:
Retrospective comparison of a consecutive surgical series.
PARTICIPANTS:
Fifty-seven consecutive patients who underwent PK at the University of California, Irvine, academic referral practice.
METHODS:
A comparison of 49 eyes of 43 patients that underwent femtosecond laser zig-zag incision pattern PK versus 17 eyes of 14
patients that underwent conventional Barron suction trephination PK performed contemporaneously. All PKs were closed
with an identical, 24-bite running nylon suture technique.
MAIN OUTCOME MEASURES:
Topographically determined astigmatism, best spectacle-corrected visual acuity (BSCVA), and recovery of full visual potential.
RESULTS:
The postoperative follow-up ranged from 1 to 12 months. There was a significant difference in average astigmatism between the
groups at postoperative month 1 (P = 0.013) and 3 (P = 0.018). By month 3, the average astigmatism was 3 diopters (D) in
the zig-zag group and 4.46 D in the conventional group. Of the patients with normal macular and optic nerve function (n(ZZ)
= 32; n(con) = 14), a significant difference in BSCVA was seen at month 1 (P = 0.0003) and month 3 (P = 0.006) with 81% of
the zig-zag group versus 45% of the conventional group achieving BSCVA of > or =20/40 by month 3 (P = 0.03).
CONCLUSIONS:
The femtosecond laser generated zig-zag-shaped incision results in a more
rapid recovery of BSCVA and induces less astigmatism compared with
conventional blade trephination PK.
FINANCIAL DISCLOSURE(S):
Proprietary commercial disclosure may be found after the references.