Exposing the LASIK Scam

Journal of Refractive Surgery
Volume 21 September/October 2005

Pg 433

Cohesive Tensile Strength of Human LASIK Wounds With Histologic, Ultrastructural, and Clinical Correlations

Excerpt:


The clinical knowledge gained from the LASIK flap lift
retreatment cases correlated well with the laboratory
results. The tip of the Sinskey hook typically fell
into the LASIK wound margin with minimal effort
correlating with the gap in Bowman?s layer seen histopathologically.
Most of the resistance when lifting the
flap occurred at the flap margin, particularly the cases
>1 year after surgery and those with the wound in the
corneal limbus, correlating with the area of hypercellular
fibrotic stromal scarring and its greater measured
tensile strength. Conversely, the resistance to lifting the
flap in the central and paracentral regions of the interface
wound was always minimal, correlating with the
area of the hypocellular primitive stromal scarring and
its lesser tensile strength. In some eyes, after the flap
was lifted, the surface of the residual stromal bed in the
central interface wound showed visible circular zones
from previous broad area excimer laser ablation, further
attesting to the minimal healing described pathologically
in the central and paracentral LASIK bed.
This study shows that the primary structural reason
for the high cohesive tensile strength of normal corneal
stroma is the collagen fibrils from interweaving corneal
lamellae and the groups of bridging collagen fi laments
where stromal lamellae cross one another. Corneal stromal
LASIK wounds were found to heal weaker than
normal because these structures were not regenerated
during the healing response. Moreover, the central and
paracentral stromal LASIK wounds were found to heal
by producing a hypocellular primitive stromal scar
that is very weak in tensile strength, averaging 2.4% of
normal, and displays no evidence of remodeling over
time in specimens out to 6.5 years after surgery. In contrast,
the more superficial, flap margin stromal LASIK
wound, which is adjacent to the surface epithelium,
was found to heal by producing a 10-fold stronger, hypercellular
fibrotic stromal scar that reaches maximum
tensile strength by approximately 3.5 years after surgery,
averaging 28.1% of normal.

JRS
Vol 22, May 2006
Late Traumatic Flap Dislocations After LASIK

http://www.journalofrefractivesurgery.c ... hing=12869

Excerpts from the full text:

A number of cases of late onset traumatic LASIK flap dislocations
have been reported, raising questions about the strength
of the adhesion between the flap and the stromal bed.

In this series, we report three cases of late onset traumatic
LASIK flap displacement and their management. One patient
presented 7 years after the initial surgery, which, to our
knowledge, is the longest duration reported.

A 23-year-old man with bilateral uncomplicated LASIK 7 years prior presented 2 days after sustaining a left eye injury
by another person?s fingernail in a fight.

A 33-year-old woman underwent LASIK and pre-
sented after sustaining a broomstick injury 1 year
postoperatively.

A 38-year-old woman with a history of uncomplicated
bilateral LASIK 2 years before sustained a right eye
injury when a folder fell from a shelf.

The creation of a lamellar flap results in a potential
plane of weakness in the cornea in which shearing
forces can produce flap displacement. Recent
histological and confocal studies have shown a central
hypocellular primitive scar in the interface, allowing
easy lifting of the flap in trauma.
The fact that this potential plane can be disrupted
many years after LASIK (7 years after the initial surgery
in patient 1) indicates that corneal integrity is
compromised by the surgical procedure and takes a
long time, if ever, to restore.

Interface Corneal Edema Secondary to Steroid-induced Elevation of Intraocular Pressure Simulating Diffuse Lamellar Keratitis

Journal of Refractive Surgery Vol. 22 No. 5 May 2006

J Cataract Refract Surg. 2006 Aug;32(8):1270-5.

Femtosecond laser in situ keratomileusis after radial keratotomy.

Munoz G, Albarran-Diego C, Sakla HF, Perez-Santonja JJ, Alio JL.
From the Refractive Surgery Department, Hospital NISA Virgen del Consuelo (Munoz, Albarran-Diego), Valencia, and the Refractive Surgery Department, Vissum Instituto Oftalmologico de Alicante (Munoz, Sakla, Perez-Santonja, Alio), Alicante, Spain.

PURPOSE: To assess the safety, efficacy, and predictability of femtosecond laser in situ keratomileusis (LASIK) in eyes with previous radial keratotomy (RK).

RESULTS: Although the RK incisions opened in all eyes when the flap was lifted, LASIK was successfully completed in all cases.

1: Curr Opin Ophthalmol. 2006 Aug;17(4):380-8.

How has confocal microscopy helped us in refractive surgery?

Kaufman SC, Kaufman HE.

aHenry Ford Health System: Ophthalmology, Troy, Michigan bLouisiana State University Health Science Center, New Orleans, Louisiana, USA.

PURPOSE OF REVIEW: To summarize the known uses of in-vivo confocal microscopy in refractive surgery, highlighting the current developments in the field.

RECENT FINDINGS: Examination of the cornea after laser in-situ keratomileusis demonstrated that the keratocyte density within the laser in-situ keratomileusis flap and anterior residual corneal bed continued to decline during the entire 3-year period of the study. The progressive loss of keratocytes in the flap and anterior portion of the residual corneal bed could have long-term implications in terms of corneal stability, refractive stability and cellular integrity after laser in-situ keratomileusis. Additional studies showed that the density of sub-basal nerves decreased by 90% 1 month after laser in-situ keratomileusis. At some point between 3 and 6 months after laser in-situ keratomileusis, the sub-basal nerves began to recover and by 2 years they had reached approximately 50% of their original preoperative density. Analysis of sub-basal nerve density after photorefractive keratectomy reported that the nerve density completely recovered to preoperative levels by 2 years. Other confocal microscopic studies demonstrated that the microscope can detect infectious organisms in vivo, without stains or dyes.

SUMMARY: The confocal microscope is a unique diagnostic instrument that can be used to evaluate corneal healing, long-term stability and to assess complications after refractive surgery. The ability of the device to view in-vivo cellular detail, microorganisms, inflammatory cells, epitheliod cells, fibrosis and measure the postoperative thickness of the residual corneal bed after laser in-situ keratomileusis, in a noninvasive manner, highlights the unique capabilities of this instrument.

Am J Ophthalmol. 2006 May;141(5):799-809. Epub 2006 Mar 20.

Corneal keratocyte deficits after photorefractive keratectomy and laser in situ keratomileusis.

Erie JC, Patel SV, McLaren JW, Hodge DO, Bourne WM.

Department of Ophthalmology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA. erie.jay@mayo.edu

PURPOSE: To measure changes in keratocyte density up to five years after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK).

DESIGN: Prospective, nonrandomized clinical trial.

METHODS: Eighteen eyes of 12 patients received PRK to correct a mean refractive error of -3.73 +/- 1.30 diopters, and 17 eyes of 11 patients received LASIK to correct a mean refractive error of -6.56 +/- 2.44 diopters. Corneas were examined by using confocal microscopy before and six months, one year, two years, three years, and five years after the procedures. Keratocyte densities were determined in five stromal layers in PRK patients and in six stromal layers in LASIK patients. Differences between preoperative and postoperative cell densities were compared by using paired t tests with Bonferroni correction for five comparisons.

RESULTS: After PRK, keratocyte density in the anterior stroma decreased by 40%, 42%, 45%, and 47% at six months, two years, three years, and five years, respectively (P < .001). At five years, keratocyte density decreased by 20% to 24% in the posterior stroma (P < .05). After LASIK, keratocyte density in the stromal flap decreased by 22% at six months (P < .02) and 37% at five years (P < .001). Keratocyte density in the anterior retroablation zone decreased by 18% (P < .001) at one year and 42% (P < .001) at five years. At five years, keratocyte density decreased by 19% to 22% (P < .05) in the posterior stroma.

CONCLUSIONS: Keratocyte density decreases for at least five years in the anterior stroma after PRK and in the stromal flap and the retroablation zone after LASIK.

Ophthalmology. 1997 Jul;104(7):1079-83.

Ocular integrity after refractive procedures.Peacock LW, Slade SG, Martiz J, Chuang A, Yee RW.

PURPOSE: The purpose of the study was to determine the integrity of human eyes after refractive procedures.

METHODS: Whole human globes underwent either radial keratotomy (RK) with eight incisions, automated lamellar keratoplasty (ALK), photorefractive keratectomy (PRK), or excimer laser assisted in situ keratomileusis (LASIK). Eyes then were subjected to quantitatively increasing levels of trauma until rupture occurred.

RESULTS: All eyes operated on required less energy to rupture as compared with that of control eyes. The mean number of trials required for rupture is as follows (energy doubled with each successive trial): normal, 4.29; LASIK, 3.80; ALK, 3.67; PRK, 3.60; and RK, 2.83. The level of energy required to rupture normal, ALK, PRK, and LASIK eyes was not significantly different. All RK eyes ruptured at incisions. Most ALK, PRK, and LASIK eyes ruptured near the flap edge or limbus. Most normal eyes ruptured with both corneal and scleral involvement. Age of tissue donors at the time of death and time elapsed between death and procedure were not significantly different between groups (P = 0.88 and 0.79, respectively).

Trans Am Ophthalmol Soc. 2005;103:56-66; discussion 67-8.

Long-term corneal keratoctye deficits after photorefractive keratectomy and laser in situ keratomileusis.

Erie JC, McLaren JW, Hodge DO, Bourne WM.
Department of Ophthalmology, Mayo Clinic College of Medicine, Rochester, Minnesota, USA.

PURPOSE: To measure changes in keratocyte density up to 5 years after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK).

METHODS: This was a prospective, nonrandomized clinical trial. Eighteen eyes of 12 patients received PRK to correct a mean refractive error of -3.73 +/- 1.30 D, and 17 eyes of 11 patients received LASIK to correct a mean refractive error of -6.56 +/- 2.44 D. Corneas were examined by using confocal microscopy before and 6 months, 1 year, 2 years, 3 years, and 5 years after the procedures. Keratocyte densities were determined in five stromal layers in PRK patients and in six stromal layers in LASIK patients. Differences between preoperative and postoperative cell densities were compared by using Bonferroni-adjusted paired t tests.

RESULTS: After PRK, keratocyte density in the anterior stroma was decreased by 39%, 42%, 45%, and 47% at 6 months, 2 years, 3 years, and 5 years, respectively (P < .001). At 5 years, keratocyte density was decreased by 20% to 24% in the posterior stroma (P < .05). After LASIK, keratocyte density in the stromal flap was decreased by 22% at 6 months (P < .02) and 37% at 5 years (P < .005). Keratocyte density in the anterior retroablation zone was decreased 18% (P < .005) at 1 year and 43% (P < .005) at 5 years. At 5 years, keratocyte density was decreased by 19% to 22% (P < .05) in the posterior stroma.

CONCLUSIONS: Keratocyte density is decreased in the anterior stroma after PRK and in the stromal flap and the retroablation zone after LASIK for up to 5 years. Posterior stromal keratocyte deficits are first noted at 5 years.

J Refract Surg. 2006 Nov;22(9):884-9.

Traumatic corneal flap dislocation one to six years after LASIK in nine eyes with a favorable outcome.

Landau D, Levy J, Solomon A, Lifshitz T, Orucov F, Strassman E, Frucht-Pery J.

Cornea and Refractive Surgery Unit, Dept of Ophthalmology, Hadassah University Hospital, P.O.B. 12000, Jerusalem 91120, Israel. dvl_eyes@netvision.net.il

PURPOSE: To report our experience treating eye trauma after LASIK refractive surgery.

METHODS: Nine eyes of eight patients (one woman and seven men) were treated for ocular trauma: blunt trauma (n=5), sharp instrument trauma (n=2,) and trauma from inflation of automobile air bags during a traffic accident (n=2). The time from LASIK varied between 3 months and 6 years. All patients were hospitalized as a result of severe decrease in visual acuity and pain.

RESULTS: Seven of nine LASIK flaps had some degree of dislocation and were lifted, irrigated, and repositioned. Two flaps were edematous without dislocation. Intensive topical steroids and antibiotics were used in all patients up to 3 weeks after trauma. Three months after trauma, five eyes regained their pre-trauma visual acuity (between 20/20 and 20/40), and three eyes lost one line of best spectacle-corrected visual acuity.

CONCLUSIONS: Trauma occurring several months or years after LASIK may cause flap injury. Adequate and prompt treatment usually is successful.

Curr Eye Res. 2006 Nov;31(11):903-8.

Healing process at the flap edge in its influence in the development of corneal ectasia after LASIK.

Abdelkader A, Esquenazi S, Shihadeh W, Bazan HE, He J, Gill S, Kaufman HE.

Department of Ophthalmology, LSU Eye and Neuroscience Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA.

Flap Dislocation After LASIK/Landau et al
Traumatic Corneal Flap Dislocation One to Six Years After LASIK in Nine Eyes With a Favorable Outcome
Journal of Refractive Surgery Vol. 22 No. 9 November 2006

Our report, as well as the related literature, indicates that the healing of the flap is incomplete even 6 years after LASIK surgery. The exact mechanism of long-term adhesion remains unclear. In an animal model, Maurice and Monroe20 demonstrated that after creation of a lamellar corneal stromal dissection, the adhesive force of the healed stroma lamellae approximated one-quarter to one-half that of normal. Perez et
al21,22 suggested that drying increases stromal-stromal adhesion due to the increased concentration of surface molecules, which have high ionic charge densities and ionic binding. In rabbit corneas, the wound healing reaction after LASIK takes place only at the periphery of the microkeratome wound, leaving the central optical zone clear; similar findings have been described in human eyes after LASIK.

Laceration and Partial Dislocation of LASIK Flaps 7 and 4 Years Postoperatively With 20/20 Visual Acuity After Repair

Journal of Refractive Surgery Vol. 22 No. 9 November 2006

George J.C. Jin, MD, PhD; Kevin H. Merkley, MD, MBA

http://www.ascrs.org/publications/jcrs/editjun02.html



Ref:
Anderson N.J., Edelhauser H.F., Sharara N. Histologic and ultrastructural findings in human corneas after successful laser in situ keratomileusis. Arch Ophthalmol 2002; 120:288?293

J CATARACT REFRACT SURG?VOL 29, APRIL 2003

Histological and immunohistochemical findings after laser in situ keratomileusis in human corneas

Wolfgang E. Philipp, MD, Lilly Speicher, MD, Wolfgang Gottinger, MD

From the full text:

Not peer-reviewed:

Cataract & Refractive Surgery Today
June, 2007

http://www.crstoday.com/Pages/News.php

Keratocytes' Density Remains Low After Refractive Surgery

According to a paper presented this month at the 6th International Congress on Advanced Surface Ablation and SBK, keratocytes' density decreases substantially in the anterior stroma of refractive surgery patients during the first postoperative year and remains low for several years.1

William M. Bourne, MD, from the Mayo Clinic College of Medicine in Rochester, Minnesota, performed confocal microscopy on 34 eyes of 23 patients who underwent PRK or LASIK. At 7 years postoperatively, the density of keratocytes in the anterior stroma of PRK patients had dropped from 45,000 to 33,000 cells/mm?, a total decrease of approximately 28%. He found a similar decrease (29%) in LASIK patients, whose keratocytes' density dropped from approximately 49,000 cells/mm? preoperatively to approximately 35,000 cells/mm? at 7 years postoperatively.

Because keratocytes secrete the collagen and proteoglycan necessary for the long-term maintenance of corneal clarity and curvature, the loss of these cells after refractive surgery may have long-term consequences for patients' corneal health, said Dr. Bourne. "We feel this possibility is unlikely, but cannot be ruled out," he added.

1. Bourne WM. The effect of PRK and LASIK on corneal keratocytes. Paper presented at: The 6th International Congress on Advanced Surface Ablation and SBK; May 5, 2007; Fort Lauderdale, FL.