Ophthalmology. 1998 Sep;105(9):1721-6.


Diffuse lamellar keratitis. A new syndrome in lamellar refractive surgery.

Smith RJ, Maloney RK.

Jules Stein Eye Institute, UCLA School of Medicine, USA.

OBJECTIVE: This study aimed to describe a syndrome that the authors call diffuse lamellar keratitis that follows laser in situ keratomileusis (LASIK) and related lamellar corneal surgery. DESIGN: Noncomparative case series and record review.

PARTICIPANTS: Thirteen eyes of 12 patients in whom infiltrates developed in the interface after lamellar refractive surgery were studied.

INTERVENTION: Topical antibiotics or corticosteroids or both were administered.

MAIN OUTCOME MEASURES: Corneal infiltrate appearance, focality, location, and clinical course were measured.

RESULTS: Patients presented between 2 and 6 days after surgery with pain, photophobia, redness, or tearing. Ten cases directly followed either myopic keratomileusis or LASIK. Three cases followed enhancement surgery without the use of a microkeratome. All 13 cases had infiltrates that were diffuse, multifocal, and confined to the flap interface with no posterior or anterior extension. The overlying epithelium was intact in each case. Cultures were negative in the two cases cultured. Ten eyes were treated with antibacterial agents; two eyes had fluorometholone four times daily added to the routine postoperative antibacterial regimen, and one eye had the antibacterial agent discontinued and was treated with topical fluorometholone alone. All infiltrates resolved without sequelae.

CONCLUSIONS: A distinct syndrome of unknown cause of noninfectious diffuse infiltrates in the lamellar interface is described. It can be distinguished from infectious infiltrates by clinical presentation and close follow-up. Patients with the syndrome should be spared the more invasive treatment of infectious keratitis.

================================


I am seldom at a loss for words. I wanted to add a comment to this article but as I sat here, thinking about DLK (first hand experience), reading an article that exposes the truth that DLK was unheard of before LASIK, yet since LASIK there have been thousands of cases, numerous reports in the medical literature as well as a hot topic in the industry tabloids, I could not think of anything to say. I put my fingers on the keyboard anyway and just started typing.

One of the first things that came to mind was the article that appeared in the JRS in 2002 titled "A Mysterious Tale: A Search for the Cause of 100+ Cases of Diffuse Lamellar Keratitis". It was submitted for publication anonymously, probably at least in part to protect this doctor from medical malpractice lawsuits. Surgeon X had a DLK rate at one point as high as 50%. For those who are unfamiliar with DLK, it can cause permanent vision loss from scarring, or even loss of the cornea entirely. I found it unbelievable that this surgeon continued performing LASIK while he "searched for the cause". Do you think he informed his patients that his rate of DLK was 50%? Sounds like he used his patients as human guinea pigs. How do these surgeons sleep at night?

LASIK is an elective surgery performed on a vital sensory organ. I see people comparing it to other elective surgeries. It is your eyes, your vision, your primary interface with the world! Come on, that's not the same as other elective surgeries. This kind of elective surgery should be held to much, much higher standards because vision is so precious and so important to a person's overall well-being and quality of life. A person presenting for LASIK is not sick, does not have a disease, and lives a perfectly normal life with great correctable vision.

I have such a hard time understanding how "doctors" can promote a surgery that triggers so many adverse, life-altering "side effects" in a normal healthy human being.

DLK is not the only new syndrome induced by LASIK.

"Neurotrophic keratopathy" and "neurotrophic epitheliopathy" are terms used to describe LASIK induced dry eye which results from the severing of the corneal nerves by the microkeratome. Doctors routinely tell their patients that dry eyes is a temporary condition and advise the use of artificial tears for a period of weeks. The brochure given out by my LASIK surgeon said that eye drops are only needed for 2 weeks. Excuse me, it's over 5 years later, and I still use eye drops daily due to horrible dry eye with associated pain and burning. One peer-reviewed article showed that at 3 years post-op the corneal nerves were still less than 60% of pre-op densities. No article has ever shown that the nerves fully recover to their normal patterns. Yet surgeons don't inform patients that their corneal nerves will be permanently damaged.

There's another new syndrome of the Intralase flap. Patients were coming back in the early post-op period with such extreme light sensitivity that they had to wear dark sunglasses indoors. Surgeons were so puzzled by this that it left them scratching their heads. Finally one surgeon coined the term "Transient Light Sensitivity", or TLS for short, and it made them all very happy that now there was a term for it. Now, instead of looking like a moron to their patients because they didn't have a diagnosis, they could say "Oh, you have TLS", give them some steroids and a pat on the head and send them on their way. (Hey Moron, be sure to warn your patients of the dangers of prolonged steriod use and monitor their IOP closely!)

This article shows that patients who think they are out of the woods because one day or one week post-op they have 20/20 acuity and no complications could be in for an unpleasant late surprise.


Reports:
Diffuse Lamellar Keratitis 6 Months After Uneventful Laser in situ Keratomileusis

Journal of Refractive Surgery Vol. 19 No. 1 January/February 2003
José I. Belda, MD, PhD; Alberto Artola, MD, PhD; Jorge Alió, MD, PhD

PURPOSE
Diffuse lamellar keratitis after laser in situ keratomileusis (LASIK) typically occurs between 1 and 7 days after the procedure, and its etiologic factor(s) remain unknown.

METHODS
We describe a case of diffuse lamellar keratitis 6 months after uneventful LASIK in a 25-year-old woman.

RESULTS
Slit-lamp microscopy showed a diffuse infiltrate confined to the interface, extending to the visual axis, with no other relevant findings. Late on-set diffuse lamellar keratitis was our provisional diagnosis and treatment with topical corticosteroids was instituted, with rapid response and improvement of the clinical signs and symptoms.

CONCLUSIONS
This case supports the theory that a previously inert inciting agent could cause a delayed toxic or inflammatory response of the cornea several months after surgery. [J Refract Surg 2003;19:70-71]

==========================================

From the full text:
"Possible etiologies include metallic debris from the microkeratome or blade, bacterial endotoxins, meibomian gland oils, debris from corneal ablation or from absorbent sponges, povidone-iodine solutions, and surgical glove talc."

This is not a peer-reviewed article but it has a picture of grade 4 DLK for reference:

http://www.eyeworld.org/article.php?sid=2997

Eyeworld
Feb. 2006

Thin Flaps Studied for Risk

J Cataract Refract Surg. 2005 Dec;31(12):2340-2344.


Diffuse lamellar keratitis complicating laser in situ keratomileusis Post-marketing surveillance of an emerging disease in British Columbia, Canada, 2000-2002.

Bigham M, Enns CL, Holland SP, Buxton J, Patrick D, Marion S, Morck DW, Kurucz M, Yuen V, Lafaille V, Shaw J, Mathias R, Vanandel M, Peck S.



PURPOSE: To describe a surveillance system and summarize data between January 2000 and December 2002 regarding diffuse lamellar keratitis (DLK), a complication of laser in situ keratomileusis (LASIK) surgery.

SETTING: Community-based clinics in British Columbia, Canada, in which LASIK surgery is performed.

METHODS: Monthly, all clinics in which LASIK is performed reported the number of LASIK procedures and nonnominal cases of DLK (by grade and onset date) to the British Columbia Centre for Disease Control. Diffuse lamellar keratitis outbreaks were investigated, and prevention and control measures were recommended.

RESULTS: From 2000 to 2002, approximately 72 000 LASIK procedures were performed, with a mean DLK incidence rate of 0.67% (95% confidence interval, 0.61-0.73). The overall proportion of DLK cases attributed to outbreaks was 64%, decreasing from 72% in 2000 to 40% in 2003.

CONCLUSIONS: An effective DLK surveillance program was implemented at all laser refractive clinics in British Columbia. Reported DLK incidence was 0.67 cases per 100 procedures, with 64% occurring in outbreaks.

Ophthalmol Clin North Am. 2002 Mar;15(1):35-40.

Lamellar keratitis following laser-assisted in situ keratomileusis.

Chao CW, Azar DT.

Division of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, 243 Charles Street, Boston, MA 02114, USA.

Distinguishing between an infectious or sterile lamellar keratitis is the most important first step in evaluating patients with interface infiltrates after LASIK. The mechanisms by which infectious keratitis develops are more straightforward than for DLK and deal with the introduction of microbial pathogens into the lamellar flap during LASIK. Prevention emphasizes reducing contamination risks and treating any pre-existing ocular infections. The mechanisms of the development of DLK are likely multifactorial, and factors such as microkeratome debris, eyelid secretions, other debris, epithelial defects, and bacterial endotoxin have been suggested. Overall, much remains to be elucidated in order to devise effective prevention measures.

Journal of Refractive Surgery Volume 17 May/June 2001

Complications of Laser in situ Keratomileusis:
Etiology, Prevention, and Treatment

Renato Ambrósio Jr, MD; Steven E. Wilson, MD

Excerpts:

Smith and Maloney thoroughly described diffuse
lamellar keratitis (DLK) (American Academy of
Ophthalmology, San Francisco, CA, November,
1997).71 Other reports have appeared since that
time (Linebarger EJ. Diffuse lamellar keratitis:
trouble in paradise? ASCRS Film Festival, Grand
Prize Winner, 1999).20,41,72-78 It has also been called
sands of the Sahara syndrome (Bobby Maddox, MD,
El Paso, TX, coined the phrase), because of the characteristic
wavy appearance at slit-lamp examination.


In severe cases, it is associated
with stromal necrosis and irregular astigmatism.


However, we
have seen two cases of infectious keratitis in which
treatment was inappropriately delayed because of
erroneous diagnosis of DLK. Both cases had severe
vision loss.


The incidence of DLK is highly variable. One
report noted an incidence of approximately 1 in
500.74 Some high volume LASIK surgeons have
reported never seeing a case in their own practice.
We have seen only two mild cases in 3000 LASIK
procedures. Others have experienced focal outbreaks
of DLK that have included dozens of
patients.


Another grading system has been
proposed by Linebarger (Linebarger, 1999, cited
above).75
Stage 1 DLK is typically seen on day 1
postoperatively as white, granular cells in the
periphery with sparing of the visual axis.
Stage 2 Typically seen on postoperative day 2 or
3, shows white cells in the visual axis.
Stage 3 DLK involves an aggregation of cells
clumped in the visual axis and associated with haze
and reduced vision.
Stage 4 Involves central stromal necrosis, melt,
and secondary hyperopia with irregular astigmatism.


At the other extreme, severe (grade 4) cases
typically have decreased vision and severe pain
associated with marked interface inflammation and
necrosis that results in topographic flattening of the
corneal contour, secondary irregular astigmatism,
and poor vision.


Many potential etiologies for DLK have been proposed
(Linebarger, 1999, cited above).75-77 Most of
these are based on speculation without supporting
data. These have included betadine from surgical
preps, impure balanced salt solution, retained meibomian
secretions and other tear film components,
metallic debris, use of improper detergents, talc
from gloves, thermal effects from the excimer laser,
lubricants on the microkeratome or blades, topical
medications such as anesthetics, bacterial cell wall
hypersensitivity, and biofilms from inadequate sterilization
protocols.


The bacterial cell wall hypersensitivity mechanism
could have been the underlying factor in a
recent epidemic of DLK.77 The authors suggested
that the microkeratome or irrigating cannula
became contaminated by bacteria. These bacteria
may reside in water left standing in the sterilizer. If
the contaminated instruments are cleaned and left
to dry, bacteria could proliferate on residual trace
protein and the bacterial cell count could increase
significantly.


These data suggest that injury
to the surface epithelium or epithelial debris left
within the LASIK interface triggers production of
factors that are chemotactic for inflammatory cells
via interleukin-1 release. This mechanism could
account for many DLK cases.


Surgical technique may limit DLK, whatever the
underlying mechanism.


Eyes with severe DLK are at high risk for stromal
necrosis that may be focal and result in haze, irregular
astigmatism, and hyperopic shift.

BMC Ophthalmol. 2006 Apr 28;6(1):19

Hyeropic shift after LASIK induced Diffuse Lamellar Keratitis.

Dada T, Pangtey MS, Sharma N, Vajpayee RB, Jhanji V, Sethi HS.

ABSTRACT:

BACKGROUND: Diffuse lamellar keratitis (DLK) is a relatively new syndrome that is increasingly being reported after LASIK. We have observed that a hyperopic shift may be associated with the occurrence of this diffuse lamellar keratitis.

CASE PRESENTATION: A 26 year old man developed bilateral diffuse lamellar keratitis (DLK) following myopic LASIK. The residual refractive error was +0.5D OD and +0.25D OS at the end of the first week. The sterile infiltrates resolved over a period of 4-6 weeks on topical steroid therapy. A progressive hyperopic shift was noted in the right eye with an error +4.25Dsph/+0.25Dcyl 20 at the final follow up 6 months post surgery.

CONCLUSION: Diffuse lamellar keratitis after LASIK may be associated with a significant hyperopic shift.

J Cataract Refract Surg. 2006 Feb;32(2):264-8.

Role of topical fluoroquinolones on the pathogenesis of diffuse lamellar keratitis in experimental in vivo studies.

Mah FS, Romanowski EG, Dhaliwal DK, Yates KA, Gordon YJ.

From the full text:

This one is not peer-reviewed:

OCULAR SURGERY NEWS U.S. EDITION October 1, 2006

Tips for preventing and treating epithelial ingrowth after LASIK

There are a number of treatment options available if epithelial ingrowth occurs.

By Amar Agarwal, MS, FRCS, FRCOphth

Excerpts:








Read the entire article at: www.osnsupersite.com

Another case report of late onset DLK:


J Refract Surg. 2006 Oct;22(8):826-7.

Late onset diffuse lamellar keratitis as a result of the toxic effect of Ecballium elaterium herb.

Kocak I, Karabela Y, Karaman M, Kaya F.
Department of Ophthalmology, Nisa Hospital, Istanbul, Turkey. ikocak@ttnet.net.tr

PURPOSE: To report a case of late onset diffuse lamellar keratitis (DLK) 11 months after LASIK due to Ecballium elaterium exposure. METHODS: A 25-year-old man underwent bilateral LASIK. No complications were observed during the early postoperative period. RESULTS: Eleven months after LASIK surgery, grade II DLK was diagnosed after an Ecballium elaterium herb seed burst and splashed into the patient's left eye. Topical steroid treatment was administered and DLK healed in 2 weeks without complication. CONCLUSIONS: Although DLK typically develops in the early postoperative period, it could occur months after surgery. Treatment should begin as soon as DLK is diagnosed.

DLK first reported:

Maddox B. Interface inflammation following LASIK. Presented
at: American Society of Refractive and Cataract Surgery; April
26-30, 1997; Boston, Mass.

Central Flap Necrosis After LASIK With Microkeratome and Femtosecond Laser Created Flaps

Journal of Refractive Surgery Vol. 23 No. 3 March 2007

Bryan C. Hainline, MD; Marianne O. Price, PhD; David M. Choi, MD; Francis W. Price Jr, MD

Confocal Microscopy and Histopathological Examination of Diffuse Lamellar Keratitis in an Experimental Animal Model

Journal of Refractive Surgery Vol. 23 No. 3 March 2007

Ma Victoria de Rojas Silva, MD, PhD; Maximino J. Abraldes, MD, PhD; Elío Díez-Feijóo, MD, PhD; Purificación Mera Yáñez, MD; Jaime Javaloy, MD, PhD; Manuel Sánchez-Salorio, MD, PhD

Description, Etiology, and Prevention of an Outbreak of Diffuse Lamellar Keratitis After LASIK

Journal of Refractive Surgery Vol. 23 No. 5 May 2007

Alberto Villarrubia, MD; Elisa Palacín, MD; Miguel Gómez del Río, NP; Purificación Martínez, MD

PURPOSE
To describe an outbreak of diffuse lamellar keratitis (DLK) and provide a hypothesis about the etiology.

METHODS
A retrospective analysis was carried out on 328 eyes of 220 patients who underwent LASIK over 9 months. The occurrence of DLK using two different methods of cleaning and sterilizing surgical instruments and an autoclave reservoir were analyzed. Microbial analyses were carried out by two laboratories on samples obtained from the original autoclave reservoir and tubing. A chi-square test was used to compare qualitative values. The Student t test was used to compare numerical values.

RESULTS
Forty-six (24.5%) of 188 cases of DLK were diagnosed. Sphingomona paucimobilis and Burkholderia pickettii were isolated in the reservoir of the steam sterilizer. Electron microscopy revealed gram-negative microbes on the tubing walls. After changing the reservoir of the steam sterilizer and implementing a new cleaning and sterilization protocol based on air-drying the instruments and draining and drying the reservoir of the sterilizer, the occurrence of DLK stopped. No statistically significant correlation was noted between the occurrence of DLK and gender, age, or volume of tissue removed.

CONCLUSIONS
Data obtained during this DLK outbreak support the theory that a bacterial endotoxin, which can survive short-cycle steam sterilization, could be responsible for an outbreak of DLK. We recommend cleaning and sterilization protocols based on air-drying surgical instruments and leaving the reservoirs completely dry at the end of each surgical day. [J Refract Surg. 2007;23:482-486.]

From the full text:

Matched Population Comparison of the Visian Implantable Collamer Lens and Standard LASIK for Myopia of –3.00 to –7.88 Diopters

Journal of Refractive Surgery Vol. 23 No. 6 June 2007

Donald R. Sanders, MD, PhD