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CASE REPORT
Suction loss during thin-flap femto-LASIK:
Management and beneficial refractive
effect of the epithelium
David Smadja, MD, Marcony R. Santhiago, MD, Glauco Reggiani Mello, MD,
Edgar M. Espana, MD, Ronald R. Krueger, MD, MSE
We report the case of a 42-year-old man who experienced loss of suction during thin-flap femtolaser in situ keratomileusis, leading to a stromal step in the superior cornea where the cutting was
stopped. The procedure was converted to photorefractive keratectomy 2 weeks later. Management
of the loss of suction and the beneficial role played by the epithelium postoperatively on the
refractive outcomes are discussed.
Financial Disclosure: No author has a financial or proprietary interest in any material or method
mentioned.
J Cataract Refract Surg 2012; 38:902–905 Q 2012 ASCRS and ESCRS
Flap creation is one of the most important steps in the
laser in situ keratomileusis (LASIK) procedure.
Although the introduction of the femtosecond laser
to create the flap has improved the safety and predictability of flap creation, complications still occur.1,2
Incomplete flap creation due to suction loss is a potentially vision-threatening complication, especially
when it occurs in the central cornea. Recently, Haft
et al.1 reported the complication rate of the femtoLASIK flap in 4472 eyes. The rate of suction loss was
low, 0.06%. Binder3 also reported a small percentage
of suction loss in 1000 eyes treated with femtosecond
LASIK. Suction loss occurred in 8 eyes (0.8%); in
6 eyes, surgery was postponed and in 2 eyes, it was
performed on the same day.
We report a case in which suction loss occurred
during femto-LASIK, resulting in a stromal step in
the area where the cutting was stopped. The procedure
was converted to photorefractive keratectomy (PRK)
2 weeks later. The stromal step corresponded to the
area where the suction was lost and the laser cut was
extended to a more anterior stromal plane. The
Submitted: August 4, 2011.
Final revision submitted: October 4, 2011.
Accepted: October 5, 2011.
From the Department of Refractive Surgery, Cole Eye Institute,
Cleveland Clinic Foundation, Cleveland, Ohio, USA.
Corresponding author: David Smadja, MD, 1701 East 12th, W22Q–
Cleveland, Ohio 44114, USA. E-mail: [email protected].
902
Q 2012 ASCRS and ESCRS
Published by Elsevier Inc.
management of suction loss and the beneficial refractive effects of the epithelium, compensating for the
stromal irregularity, are discussed.
CASE REPORT
A 42-year-old white man with no medical or ocular history
was scheduled for myopic LASIK in his right eye, leaving
the left eye with temporary monovision and possible correction later. The preoperative manifest refraction was 3.50
C1.25 2 in the right eye and 2.50 C0.75 174 in the
left eye. The topography (Humphrey Atlas, Carl Zeiss
Meditec AG) was normal (Figure 1). In the right eye, ultrasound pachymetry was 560 mm and the corneal diameter
was 12.12 mm in the horizontal axis and 11.16 mm in the vertical axis. The wavefront measurement (Ladarwave, Alcon
Laboratories, Inc.) through a 6.5 mm pupil in the right eye
showed 0.42 mm root mean square (RMS) of higher-order
aberrations, 0.26 mm RMS of coma, and 0.19 mm of spherical
aberration.
The LASIK procedure was performed in December 2010.
The first step of the procedure used an Intralase 60 kHz femtosecond laser (Abbott Medical Optics, Inc.) to create the
flap. The flap was 100 mm thick, 9.0 mm in diameter, and
had a superior hinge and pocket. The laser parameters for
the bed cut were 7 mm for the spot and line separations
and 0.8 mJ for the laser pulse energy. After the center of the
cornea was marked with a surgical marker, the suction
ring was centered around the limbus before the suction
was achieved. The laser’s cone was then docked into the suction ring and the cornea was found to be well centered
(Figure 2, A). The laser cutting started from the upper part
of the cornea; the lamellar dissection (raster pattern)
extended to approximately the first third before suction
loss occurred, before the cut reached the pupillary center
(Figure 2, B). Because stopping the laser cut in this type of
case is dependent on the surgeon’s reaction time in releasing
0886-3350/$ - see front matter
doi:10.1016/j.jcrs.2012.02.004
CASE REPORT: MANAGEMENT OF SUCTION LOSS DURING THIN-FLAP FEMTO-LASIK
903
with the RTvue optical coherence tomography (OCT) (Optovue). It clearly showed how the epithelium had compensated
for the stromal bed irregularity in this area, making the anterior surface smooth (Figure 3).
DISCUSSION
Management of Suction Loss
Figure 1. Normal preoperative topography.
the foot pedal, there is usually additional cutting in a more
anterior stromal plane (Figure 2, C). After suction was
unsuccessfully reapplied 3 times with instillation of a steroid
drop before each attempt to reduce the inflammatory
reaction and chemosis, the decision was made to postpone
the procedure.
Two weeks later, PRK was performed with mitomycin-C
(MMC) 0.02% applied for 30 seconds and then copiously
washed away. After the epithelium was removed, a fine
stromal step could be seen in the superior part of the cornea,
corresponding to the area where the suction was lost in the
first procedure and the laser cut extended into a different
plane. An excimer laser ablation using an optimized profile
was completed on the stromal bed, and a bandage contact
lens was inserted for a week. Postoperatively, the patient received topical prednisolone acetate 1% and moxifloxacin 4
times daily for 1 week, along with artificial tears as needed.
The steroid drops were gradually tapered over the next
3 weeks.
After 1 month, the uncorrected distance visual acuity was
20/25 with a manifest refraction of 0.50 C0.5 105. No
sign of the superior stromal step was seen in the slitlamp examination, and the topography and wavefront aberrometry
showed no increased irregularity (especially with coma
remaining at the preoperative magnitude of 0.26 mm RMS).
In addition to the topography and aberrometry, a highresolution cross-sectional image of the cornea was made
It is well known that suction loss can be attributed to
factors such as small palpebral fissures, excessive eyelid squeezing, small corneal diameter, conjunctival
chemosis, or epithelium breakthrough. When suction
loss occurs, a different approach should be considered,
depending on the circumstances.
If suction is lost during the lamellar dissection and
before creation of the side cuts, attention must be
paid to the area where the cutting was suspended. Unless this occurs in the pupillary axis, we recommend
that suction is reapplied at the same location, using
the same flap parameters, same suction ring, and
same applanation cone to increase the chance of having the new cut within the primary dissection plane.
The timing to recut is also important because the
conjunctival shape can change if too much time elapses before the suction is reapplied. Although not scientifically determined, a recut within 10 minutes is
generally recommended.A If suction cannot be reapplied, postponing the procedure for at least a few
days is recommended.A In this circumstance, we think
performing PRK the same day could be detrimental to
epithelial wound healing because the corneal nerves
had been acutely severed and local inflammation
induced by the primary laser dissection.
If the suction is lost in the central cornea, a second
pass on the same day is not recommended.4 The potential for an irregular interface or the creation of 2 dissection planes due to differences in applanation pressure,
corneal hydration, or conjunctival chemosis can be
Figure 2. Thin-flap femto-LASIK creation. A: Well-centered cornea after applanation. B: Stromal lamellar dissection (raster bed pattern) starting
normally from the superior cornea. C: Loss of suction during the lamellar dissection. One can clearly see 2 edges of the raster pattern (black and red
arrows); the outermost one (red arrow) is due to the laser pulse delivery after suction loss and before the foot pedal was released.
J CATARACT REFRACT SURG - VOL 38, MAY 2012
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CASE REPORT: MANAGEMENT OF SUCTION LOSS DURING THIN-FLAP FEMTO-LASIK
Figure 3. The OCT image of epithelial hyperplasia and corneal surface smoothing 1 month after PRK. The epithelium thickens in the
periphery to compensate for the stromal depression reaching up to
145 mm thickness.
Figure 4. Histological section of a cornea to illustrate the trajectory of
the laser dissection. Left: The black line shows the intended dissection plane of the 100 mm flap. Right: The black line shows the trajectory of the dissection plane achieved by the laser.
prejudicial to the visual outcomes, as this area is critical for visual quality.
If the suction is lost during side-cut creation, recutting with a smaller flap diameter, reduced from
0.5 mm to 1.0 mm, is recommended as this prevents
the creation of tissue slivers from the inexact intersection of the primary side-cut plane with the new one.4,A
In our case, the unsuccessful reapplication of suction
was probably related to the patient’s small palpebral
fissure and the chemosis, which had compromised
the chance of maintaining suction. This led us to postpone the procedure and perform PRK with MMC
0.02% 2 weeks later rather than another LASIK flap
at a deeper plane.
At the time of epithelial removal during the PRK,
using ethanol 20% to minimize mechanical trauma,
we observed a fine superficial stromal step due to
the externalization of the laser dissection plane after
suction loss (Figure 4). Considering a mean epithelial
thickness of 40 to 50 mm,5 the intended flap depth of
100 mm, and the unexpected more superficial dissection plane achieved during the suction loss, the stromal step was unavoidable, even with careful
epithelial dissection.
Figure 5. Left: Topography 1 week after PRK showing lack of data in the superior cornea (arrow) due to the relative stromal depression. Right:
Topography 1 month after PRK showing normal curvature from epithelial compensation for the stromal depression.
J CATARACT REFRACT SURG - VOL 38, MAY 2012
CASE REPORT: MANAGEMENT OF SUCTION LOSS DURING THIN-FLAP FEMTO-LASIK
Beneficial Refractive Effect of the Epithelium
The ability of the epithelium to compensate for stromal abnormalities after irregular stromal ablation is
well-established.6 In 2003, Huang et al.7 developed
a mathematical model supporting the idea that the
epithelium smoothes the corneal anterior surface by
thinning over bumps or islands and thickening to
fill relative depression areas. In our case, the topography after 1 week clearly showed an absence of data in
the superior area where the stromal step was created
(Figure 5, left) and a return to normal contour of curvature after 1 month (Figure 5, right). The lack of
data in the superior area is likely due to poor imaging
of the relative stromal depression, still present after
1 week.
In support of our findings, Serrao et al.8 reported
slower epithelial migration in the superior quadrant,
leading to a thinner epithelial thickness during initial wound healing after PRK. They reasoned this
was due to an increase in the epithelial sloughing
rate superiorly, related to the mechanical action of
the lid.
After 1 month, high-resolution OCT imaging of our
patient’s cornea showed not only the area of stromal
depression but also a thickened epithelium, compensating for the stromal irregularity (Figure 3). This led
to a normal post-refractive surgery topography
(Figure 5, right), which is consistent with the finding
of Gatinel et al.,9 showing that the epithelium has the
ability to significantly modify the curvature, elevation,
and asphericity of corneal topography maps. The
uniformity in aberrometry can also be explained by
the surface-smoothing effect of the epithelium, as
well as the lower sampling resolution compared
with topography.
In summary, the epithelium plays an active role in
determining the final surface power of the cornea,
aiding in corneal surface smoothing after laser surface
ablation procedures. Performing a later PRK after a primary thin-flap femto-LASIK complication such as
905
suction loss with an altered laser dissection plane appears to provide a good refractive outcome and an effective management strategy.
REFERENCES
1. Haft P, Yoo SH, Kymionis GD, Ide T, O’Brien TP, Culbertson WW.
Complications of LASIK flaps made by the IntraLase 15- and
30-kHz femtosecond lasers. J Refract Surg 2009; 25:979–984
2. Moshirfar M, Gardiner JP, Schliesser JA, Espandar L, Feiz V,
Mifflin MD, Chang JC. Laser in situ keratomileusis flap complications using mechanical microkeratome versus femtosecond
laser: retrospective comparison. J Cataract Refract Surg 2010;
36:1925–1933
3. Binder PS. One thousand consecutive IntraLase laser in situ
keratomileusis flaps. J Cataract Refract Surg 2006; 32:962–969
4. Ide T, Yoo SH, Kymionis GD, Haft P, O’Brien TP. Second femtosecond laser pass for incomplete laser in situ keratomileusis flaps
caused by suction loss. J Cataract Refract Surg 2009; 35:
153–157
5. Ringvold A, Anderssen E, Kjønniksen I. Impact of the environment on the mammalian corneal epithelium. Invest Ophthalmol
Vis Sci 2003; 44:10–15. Available at: http://www.iovs.org/cgi/
reprint/44/1/10.pdf. Accessed October 6, 2011
6. Wilson SE, Mohan RR, Hong J-W, Lee J-S, Choi R, Mohan RR.
The wound healing response after laser in situ keratomileusis
and photorefractive keratectomy; elusive control of biological
variability and effect on custom laser vision correction. Arch Ophthalmol 2001; 119:889–896. Available at: http://archopht.amaassn.org/cgi/reprint/119/6/889.pdf. Accessed October 6, 2011
7. Huang D, Tang M, Shekhar R. Mathematical model of corneal
surface smoothing after laser refractive surgery. Am J Ophthalmol 2003; 135:267–278
8. Serrao S, Lombardo M, Mondini F. Photorefractive keratectomy
with and without smoothing: a bilateral study. J Refract Surg
2003; 19:58–64. Available at: http://www.visioeng.it/documents/
PRKCsmoothingBilateralstudy.pdf. Accessed October 6, 2011
9. Gatinel D, Racine L, Hoang-Xuan T. Contribution of the corneal
epithelium to anterior corneal topography in patients having myopic photorefractive keratectomy. J Cataract Refract Surg 2007;
33:1860–1865
OTHER CITED MATERIAL
A. Jankov MR II, Jovanovic V, Coskunseven E, “How to Proceed After Suction Loss in LASIK.” Cataract & Refractive Surgery Today
Europe, June 2010, pages 44–46. Available at: http://bmctoday.
net/crstodayeurope/pdfs/0610CRSTEuro_feature_jankov.pdf.
Accessed October 6, 2011
J CATARACT REFRACT SURG - VOL 38, MAY 2012