This report of a delayed traumatic dislocation of a laser in situ keratomileusis
(LASIK) corneal cap highlights the long-term dangers of the procedure. Recommendations
are made on how to approach repair of a dislocated LASIK cap.
A 28-year-old white woman came to our casualty service following uncomplicated,
bilateral LASIK performed elsewhere. Preoperative refraction was −2.25
diopters (D)OD and −3.75 DOS. Postoperatively she achieved an unaided
visual acuity of 20/20 OU. Ten months after surgery, her fingernail brushed
the left eye while she was removing a sweater, resulting in painful displacement
of the corneal cap.
The cap was repositioned using topical (0.5% tetracaine hydrochloride)
and sub-Tenon (2% lignocaine hydrochloride) anesthesia. Operative manipulation
suggested that the cap had everted, the lower edge of its nasal hinge had
torn, it had twisted about the residual hinge, and one of its edges had folded
over (Figure 1 A). The stromal bed
and cap were debrided. Three 10-0 interrupted nylon sutures were used to secure
the cap and the patient was discharged receiving preservative-free topical
antibiotics and tear supplements.
A, The LASIK (laser in situ keratomileusis)
flap of the left eye is partially torn at the nasal hinge (blue arrow) and
has folded over inferiorly (black arrow) as well as rotated on itself about
the residual hinge (white arrow). B, Gelatinous material is wiped away from
the corneal cap–stromal interface with a sterile surgical sponge.
Five days later, debris was noted in the interface between the cap and
the corneal stroma, suggesting the presence of epithelial ingrowth. With the
patient under general anesthesia, the nylon sutures were removed and the corneal
cap was everted, revealing a sheet of gelatinous material (Figure 1 B) that was wiped with a sterile surgical sponge and sent
for histologic assessment (Figure 2).
The undersurface of the cap and the stromal bed were cleaned with 100% alcohol
to destroy residual epithelium. The cap was allowed to dry and then was hydrated
before repositioning. The surface of the cap was stroked with a cyclodialysis
spatula to remove excess fluid in the interface. A soft bandage lens was applied
after debriding the epithelium on the surface of the cap.
Light microscopy of stratified
nonkeratinizing squamous epithelium with multiple intraepithelial microcysts
(arrow) (hematoxylin-eosin, original magnification ×40). The features
are compatible with epithelial ingrowth.
Forty-three days postoperatively, irregular astigmatism had reduced
unaided visual acuity to 20/200. Retroillumination photography confirmed the
recrudescence of epithelial ingrowth under the nasal part of the cap (Figure 3) with the presence of microcysts
compatible with those seen histologically. One hundred three days after the
second operation, an attempt was made to debride the epithelial ingrowth again.
On this occasion it was impossible to easily define a cleavage plane for the
cap. A small central area of corneal stroma was removed followed by scraping
of the residual cap area. A bandage lens was applied and keratoplasty was
scheduled given the poor predicted visual outcome. However, to our surprise,
the unaided visual acuity had improved to 20/40. A −1.00-D sphere/ −0.00-D
cylinder axis 135° correction improved the visual acuity to 20/20 OD.
A corneal thickness of 429 µm in the left eye vs 528 µm in the
right eye suggested that the cap had indeed been removed at the third operation.
The patient is currently being managed conservatively.
Retroillumination image of the
left eye 43 days following the second surgery. The corneal surface is normally
epithelialized but the cap-stromal interface has continued to develop epithelial
in-growth typified by the presence of microcysts (arrow).
In flap repositioning, both the stroma and cap should be thoroughly
cleaned. Alcohol, though used in our case, is not considered essential. When
the cap is replaced, optimal adhesion is achieved by eliminating excess interface
fluid by stroking the flap with a cyclodialysis spatula. A sterile surgical
sponge should be used to remove fluid from the edge of the cap. The eyelid
speculum should be left in place for 5 minutes to allow the cornea to deturgess
under the influence of the endothelial pump. Optimal cap-stromal adherence
is confirmed by the absence of independent movement of the cap when depressing
the adjacent cornea external to the cap.
Our case is the first that we know of in which dislocation of a LASIK
cap has resulted from a trivial act of daily living performed in the late
postoperative period. Recent reviews of LASIK state that cap dislocation occurs
in 0.7% to 5.8% of cases with a mean of around 2%.1- 3
These tend to occur in the first few days following surgery and may be related
to patients rubbing their eyes. In this case, the fingernail was inserted
at the stromal keratectomy plane and dislocated the flap. Debridement of edematous
corneal epithelium during vitrectomy has resulted in iatrogenic cap dislocation.4 When retreatment is performed for LASIK it is possible
to define the original cleavage plane between cap and stroma using a surgical
hook even after 1 year. These observations clearly illustrate that corneal
integrity is never fully restored after creation of a LASIK flap. The basis
for this inherent weakness has recently been reported in a rabbit model of
LASIK in which irregular corneal stromal regeneration was observed at the
wound margin.5 Flap dislocation as a potential
late complication should be discussed as part of informed consent prior to
surgery. Laser in situ keratomileusis should perhaps be contraindicated in
patients who are at high risk of sustaining glancing corneal injuries (eg,
As LASIK increases in popularity, the complication we have reported
may become more common. It is therefore important for patients to be informed
of the risk preoperatively and for general ophthalmologists to be familiar
with the optimal way to perform primary repair in case care cannot be transferred
to the original LASIK surgeon.
Corresponding author and reprints: C. K. Patel, BSc, FRCOphth, Department
of Ophthalmology, Oxford Eye Hospital, Radcliffe Infirmary, Woodstock Road,
Oxford OX3 0NJ, England (e-mail: firstname.lastname@example.org).
Patel CK, Hanson R, McDonald B, Cox N. Late Dislocation of a LASIK Flap Caused by a Fingernail. Arch Ophthalmol. 2001;119(3):447-449. doi: