Download corneal perforation after crosslinking treatment for keratoconus

CORNEAL PERFORATION AFTER
CROSSLINKING TREATMENT FOR
KERATOCONUS
G. PAGANONI – P. RAMA
SAN RAFFAELE SCIENTIFIC INSTITUTE
MILAN
Authors have no financial interest
ABSTRACT
A 32-year-old man with keratoconus developed corneal
melting five days after CXL. Corneal scraping was positive for
Acanthamoeba. Due to corneal perforation a large therapeutic
keratoplasty was performed. Although considered a safe
procedure this case emphasizes the potential risks involved in
CXL. We discuss the potential effects of deepithelialization,
contact lens placement, topical NSAIDs and anesthetics
instillation, and the possible role of apoptosis and denervation
when performing CXL.
PATIENT
32-year-old man
 good general health
 bilateral keratoconus since 1993
 CL discontinued due to intolerance
 visual acuity worsened in left eye in the last year
 keratoconus progression confirmed by 2 consecutive
topography tests
 optical pachymetry > 400 μm
 no other ocular pathology

CXL PROCEDURE

February 2008: CXL (Siena Eye Cross protocol)
9 mm epithelial removal
 15 minutes riboflavin (Ricrolin) instillation
 30 minutes UVA irradiation (CBM VEGA – CSO)
 riboflavin instillation every 2' during irradiation

Medication with:
ofloxacin drops x3
flurbiprofen drops x4
artificial tears
BANDAGE CONTACT LENS

DAY 1
patient noticed redness and conjunctival discharge
 rinsed his eyelids with TAP WATER to remove secretions
 referred to ophthalmologist: was added levofloxacin x4

DAY 3
Corneal involvement with opacification and ulceration
 Therapy prescribed:

ofloxacin x5
levofloxacin each hour
flurbiprofen x3
chloramphenicol + betamethasone ointment x4
ceftriaxone i.m. 4 g/day
prednisone p.o. 25 mg/day
DAY 5
Condition worsened
 Hospitalization and conjunctival flap scheduled

DAY 6
Patient referred to San Raffaele Hospital, presented with:
severe inflammation
 subtotal epithelial defect
 corneal ectasia
 corneal infiltrate and opacification
 ulceration and melting

Corneal scrapings for bacteria, fungi, Acanthamoeba and
herpes virus performed
 Smears were positive for Acanthamoeba
 Cultures resulted successively negative for all microorganisms

Prescribed therapy:
acyclovir 800 mg x3/day
ceftazidime i.m. 1 gr x2/day
levofloxacin every 2 hours
hexamidine every 2 hours
PHMB every 2 hours
DAY 11
Corneal perforation occurred
 Therapeutic 10 mm PK performed

Histology of the corneal button showed loss of Bowman and
Descemet membranes, stromal necrosis and severe
granulocytic infiltrate
 No Acanthamoeba, bacteria and fungi found

ACANTHAMOEBA
Can provoke inflammation, melting and corneal perforation
 A pre-existing Acanthamoeba keratitis seems unlike: patient did
not wear CL before CXL
 Soft CL contamination with tap water is a well known risk factor
 Acute infections are possible

BUT:
 Rapid progression of corneal melting is unusual even after PRK
Wagoner: “Acanthamoeba keratitis after photorefractive keratectomy” JCRS 2002
ETIOLOGY OF CORNEAL MELTING
Remain uncertain
 Sings of bacterial infection were referred since post-op day1
BUT:
 No bacteria, fungi nor herpes found on smears and cultures
 Only Acanthamoeba was present in smears
 Histology was negative

Possible risk factor are:
• infections (bacteria – Acanthamoeba)
• epithelial debridement
• use of topical NSAIDs
• corneal toxicity from topical anesthetics
• denervation
• keratocyte apoptosis?
SUMMARY
A presumed bacterial infection, in association with the lack of
integrity of the epithelium, denervation and keratocyte
apoptosis secondary to UVA irradiation, the frequent
instillation of topical anesthetics during the procedure,
NSAIDs instillation and Acanthamoeba infection may have
led to the activation of multiple noxious mechanism that
caused ulceration and corneal melting.
CONCLUSION
A risk of microbial keratitis exist in CXL due to epithelial
defect.
The post-operative use of bandage contact lens and NSAIDs
(not contempled in the original treatment) should be well
evaluated.
The role of denervation and keratocyte apoptosis following
CXL has still to be investigated.