Open Journal of Ophthalmology, 2012, 2, 34-36
http://dx.doi.org/10.4236/ojoph.2012.22008 Published Online May 2012 (http://www.SciRP.org/journal/ojoph)
Severe Diffuse Lamellar Keratitis Following Laser in Situ
Keratomileusis with an Iatrogenic Double Flap
Hidemasa Torii, Kazuno Negishi*, Murat Dogru, Kazuo Tsubota
Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan.
Received January 18th, 2012; revised February 28th, 2012; accepted March 20th, 2012
We present a case of an iatrogenic double flap created during laser in situ keratomileusis using a femtosecond laser mi-
crokeratome that resulted in development of severe diffuse lamellar keratitis (DLK). The DLK occurred mainly in the
second interface, made by the spatula accidentally and not exposed to femtosecond or excimer lasers. Because of dif-
ferences in the severity of the interface inflammatory reactions between the two layers exposed to the same spatula, an
allergic reaction to detergent, bacteria, or other chemicals could not be assumed to be the main cause of DLK. Our ob-
servations in this case may suggest an important association of neural factors with DLK, because the inflammatory re-
action occurred mainly in the deep stromal layer at the thick corneal nerves.
Keywords: Laser in Situ Keratomileusis; Femtosecond Laser; Complications; Diffuse Lamellar Keratitis
1. Case History
A 35-year-old man who had undergone bilateral laser in
situ keratomileusis (LASIK) using a 15-KHz IntraLase
femtosecond laser microkeratome (Advanced Medical
Optics, Irvine, CA) 1 week previously was referred to
our clinic for a visual disturbance in his right eye. His
bilateral visual acuity was 20/63 that improved to 20/10
with a refractive correction preoperatively. The parame-
ters of the femtosecond laser procedure were a 110-µm
flap depth, hinge angle of 60˚ for a superior hinge, 9-mm
flap diameters, and 1.45 mJ of energy for the lamellar cut
and 1.3 mJ for the side cut. Intraoperatively, a spatula
used to lift the flap was inserted accidentally into a dif-
ferent deeper layer of corneal stroma in the right eye. The
surgeon noticed wide dehiscence in the wrong layer and
created the corneal flap again in the planned layer in the
right eye (see Figure 1). The excimer laser ablation was
performed as planned; the target refractions were (–2.25 -
0.50) × 90 and (–2.00 - 0.50) × 110 in the right and left
At the initial examination in our clinic, the uncorrected
visual acuity (UCVA) was 20/160 in the right eye that
improved to 20/100 with a refractive correction of (–1.00
- 1.50) × 100. The UCVA in the left eye was 20/12.5. The
intraocular pressure was 10 mmHg bilaterally. Biomi-
croscopic examination showed corneal stromal edema
with a severe diffuse inflammatory reaction, mainly in
the deep stroma in the right eye, and no abnormal find-
ings in the left eye. The right eye was diagnosed with
severe stage 3 diffuse lamellar keratitis (DLK). The ante-
rior chamber, lens, vitreous, and fundus appeared normal
bilaterally. Pentacam (Oculus, Wetzlar, Germany) meas-
urements showed total central corneal thicknesses of 535
μm and 537 μm in the right and left eyes, respectively
(552 μm and 567 μm preoperatively), and there was a
layer of diffuse high pixel intensity in the deep stroma of
the right eye (see Figure 2(a)). The Pentacam did not
detect any abnormal findings in the left eye except for
the area of relatively high pixel intensity in the flap (see
Figure 2(b)). The DLK gradually improved with topical
steroidal treatment. The most recent examination 45
months postoperatively showed UCVA levels of 20/50
and 20/16 in the right and left eyes, respectively. A deep
stromal scar (see Figure 2(c)) was still apparent on
Figure 1. Schema of the iatrogenic double flap. The con-
tinuous line indicates the actual flap interface. The dotted
line indicates the iatrogenic rupture line. Dots indicate dif-
fuse lamellar keratitis. At the first visit, corneal stromal
edema was seen in the shaded area.
Copyright © 2012 SciRes. OJOph
Severe Diffuse Lamellar Keratitis Following Laser in Situ Keratomileusis with an Iatrogenic Double Flap 35
Figure 2. (a) Scheimpflug photograph of the right eye (1
week postoperatively). There is a diffuse layer of high pixel
intensity (arrowheads). Relatively high pixel intensity area
also can be seen in a shallower layer that is assumed to be
the flap (arrows); (b) On a Scheimpflug photograph of the
left eye (1 week postoperatively), there is an area of rela-
tively high pixel intensity in a shallower layer that is as-
sumed to be the flap (arrows); (c) Biomicroscopy of the
right eye 3 years postoperatively shows a corneal scar in the
deep stroma (arrowheads).
The femtosecond laser delivers thousands of micro-
photodisruptive pulses to a specific corneal plane to ob-
tain a smooth cut and create a stromal flap with parallel
anterior and posterior surfaces . The femtosecond la-
ser microkeratome has achieved good refractive out-
comes with a low complication rate [1,2], although sev-
eral studies have reported complications related to in-
flammatory reactions including DLK [2,3]. We present a
complicated case of severe DLK that developed in an
iatrogenic double flap after LASIK using a femtosecond
We described a rare complicated case of femtosecond
laser-assisted LASIK with an iatrogenic double flap that
resulted in development of severe DLK.
The low complication rate associated with flap crea-
tion  is an advantage of the laser microkeratome.
Nonetheless, in the current case, the surgeon ruptured the
deep stromal layer that resulted in the iatrogenic double
DLK is characterized by an inflammatory response at
the flap interface after LASIK. Although the detailed
etiology is unknown , DLK has been attributed to
multiple etiologies including bacterial endotoxins, chem-
icals, or debris produced during autoclaving or by surgi-
cal gloves and drapes, marking pens, meibomian gland
secretions, atopy, iatrogenic epithelial defects, low mean
endothelial cell density, and wide palpebral fissure height
. DLK currently is thought to be related to the manner
in which endogenous factors modulate the patient re-
sponse to exogenous exposures .
The development of DLK after LASIK performed with
a mechanical microkeratome is well recognized. In con-
trast, the incidence of DLK after LASIK performed with
a femtosecond laser has been reported previously [3-7].
The incidence rates of DLK after LASIK in which a laser
keratome is used vary considerably and are higher than
with a mechanical microkeratome. It also has been re-
ported that higher laser energy levels may result in higher
In the current case, there was a layer of diffuse high
pixel intensity in the deep stroma of the right eye, which
was the layer into which the surgeon accidentally in-
serted the spatula (see Figure 2(a)). A Scheimpflug im-
age showed inflammation in the deep stromal layer
where dehiscence was present and not in the actual flap
layer. Stromal cell necrosis associated with a femtosec-
ond laser flap likely contributes to greater inflammation
after LASIK, especially with higher energy levels that
result in higher rates of keratocyte cell death . It also
was hypothesized that accumulated gas bubbles and
femtosecond laser energy may increase the inflammatory
response in patients who might be more susceptible to
DLK . However, in the current case, the DLK mainly
developed in the second interface that was not exposed to
femtosecond or excimer lasers. In addition, the associa-
tion with exogenous factors such as an allergic reaction
to detergent, bacteria, or other chemicals could not be
assumed to be the main cause of DLK in the current case
because of the differing severities of the interface in-
flammatory reactions between the two layers, despite
almost the same procedure with the same instruments
except laser ablation. Alio et al. reported that corneal
innervation probably is involved in both the immediate
inflammatory response and long-term healing after LA-
SIK and photorefractive keratotomy . Previous studies
have shown that the ciliary nerves of the ophthalmic
branch of the trigeminal nerve radially penetrate the cor-
nea in the deep peripheral stroma and then course anteri-
orly and the diameter increases with increasing distance
from the anterior corneal surface . In the current case,
we believe that there was an important association of
neural factors with DLK, because the inflammatory reac-
tion developed mainly in the deep stromal layer where
the thick corneal nerves were damaged mechanically.
Further studies on the mechanisms of inflammation in
Copyright © 2012 SciRes. OJOph
Severe Diffuse Lamellar Keratitis Following Laser in Situ Keratomileusis with an Iatrogenic Double Flap
Copyright © 2012 SciRes. OJOph
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