Induced Cataract

Posts from the Surgical Eyes Bulletin Board

Post 1: "Hello. At this moment, I am three months post lasik. One month after the procedure, I developed cataracts in both eyes. They WERE NOT there before the surgery. I have read other cases where cataracts developed quickly after lasik surgery, though the medical profession will not account that lasik caused this. I am 23 years old. I am taking no medication. I do not have any other explanation to why my cataracts developed besides the lasik procedure. The likelyhood is just too great."

Post 2: "Immediately prior to my LASIK surgery in February 1999, my eyes were examined by an ophthalmologist and an optometrist in my pre-op appointments. Both pronounced my eyes to be very healthy, just very myopic. I was -13.5 right and -14.5 left. Nobody suggested that I might be at a higher risk for complications due to the severity of my nearsightedness. The surgery was uneventful. Immediately afterwards my eyes became very dry, and my vision began to get increasingly worse, like I had Vaseline in them. The opthalmologist was concerned and had me return for frequent follow-up visits. He had me continue taking 4 drops of FML, a topical steroid eyedrop, for 6 weeks to combat the dry eyes and in hopes of improving the vision. At each visit my best corrected vision declined until at 6 weeks I was about 20/100 in both eyes. It was at this visit that the doctor found small posterior subcapsular cataracts in both eyes--dead center where the laser would have worked. We were all shocked. Both doctors confirmed (one in writing) that the cataracts were not there before LASIK. I was 39 years old then, had no family history of cataracts or other risk factors for cataracts, and had never used steroids except for the 4 drops of FML for 6 weeks."

This was posted by an ophthalmologist in response: "On many different threads I have repeatedly brought attention to the alarming frequency of cataracts arising shortly after LASIK or PRK. The point that I have been unsuccessful in bringing across is that, if you suspected you would need cataract/implant surgery to begin with, you would never have LASIK or PRK because cataract/implant surgery can itself correct all refractive errors and even astigmatism to a large extent. To repeat, these cataracts have been reported again and again in relatively young customers who have taken no or innocuous doses of steroids."

Articles regarding damage to the crystalline lens and associated induced cataract after LASIK:

Ophthalmology. 2001 Jun;108(6):1070-4.
Stress wave amplitudes during laser surgery of the cornea.
Krueger RR, Seiler T, Gruchman T, Mrochen M, Berlin MS.
Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.

PURPOSE: To determine the stress wave amplitudes generated during photoablation of the cornea using an argon fluoride excimer laser.

DESIGN: Experimental study using porcine eyes. METHODS: Profiles of the stress wave amplitudes and enucleated human eyes along the axis of symmetry of porcine eyes and enucleated human eyes were measured using a miniature piezoelectric transducer. The ablation parameters, fluence, and ablation diameters were varied within the range of clinical application.

MAIN OUTCOME MEASURES: Stress wave amplitudes generated during photoablation.

RESULTS: The stress waves pass through a pressure focus located in the posterior lens and anterior vitreous, where amplitudes of up to 100 atm were measured with a 6-mm or larger ablation zone. Posterior to this focus, the stress wave amplitudes rapidly decrease to less than 10 atm at the retinal site. Small diameter excimer laser spots (< or =1.5 mm) produce a declining stress wave with no pressure focus at the lens and anterior vitreous.

CONCLUSIONS: Stress waves may be potentially hazardous to anterior structures of the human eye, including the corneal endothelium, lens and anterior vitreous face. They peak at the lens and vitreous with a broad beam, but not with small spot laser ablation. At posterior retinal and subretinal structures, they may be considered harmless.

Am J Ophthalmol. 1999 Oct;128(4):507-9.
Iatrogenic cataract after laser-assisted in situ keratomileusis.
Nakamura K, Bissen-Miyajima H, Arai H, Toda I, Hori Y, Shimmura S, Tsubota K.
Department of Ophthalmology, Tokyo Dental College, Chiba, Japan.

PURPOSE: To report a case of corneal opacity and iatrogenic cataract after laser-assisted in situ keratomileusis.

METHOD: Case report. A 44-year-old man was initially seen with a traumatic cataract, corneal stromal opacity, and defect of the endothelium in the right eye after laser-assisted in situ keratomileusis performed by a plastic surgeon who had no ophthalmologic training.

RESULTS: It was speculated that repeated ablations resulted in corneal perforation. We immediately performed phacoemulisification to remove the cataract and to prevent phacolytic glaucoma. However, visual acuity remained 20/200 because of the corneal stromal opacity, and penetrating keratoplasty was performed 2 months later, which improved best-corrected visual acuity to 20/30.

CONCLUSIONS: This case demonstrated that laser-assisted in situ keratomileusis can cause devastating damage to the eye.

Cornea 2000 Jan;19(1):75-9
PRK and LASIK--their potential risk of cataractogenesis: lipid peroxidation changes in the aqueous humor and crystalline lens of rabbits.
Wachtlin J, Blasig IE, Schrunder S, Langenbeck K, Hoffmann F.

Department of Ophthalmology, Free University of Berlin, Germany.

PURPOSE: There are insufficient data on the possible cataractogenic side effects of excimer laser corneal surgery. Higher malondialdehyde (MDA) levels could indicate oxidative events related to the cataractogenic process. We therefore examined MDA levels after refractive laser surgery.

METHODS: Six white Russian rabbits received laser in situ keratomileusis (LASIK) (Schwind keratome) in the right eye and a 250-microm-deep microkeratome cut (Schwind microkeratome) in the left eye. Six others underwent photorefractive keratectomy (PRK) in the right eye; the left eye remained untreated. The 180 mJ/cm2 fluence applied at a rate of 10 Hz with an optical zone diameter of 5 mm in all rabbits (438 pulses) resulted in an estimated central photoablation depth of 116 microm. Two weeks later, lenses and aqueous were taken immediately after death. MDA was detected in aqueous and homogenate of lenses after reacting with thiobarbituric acid (TBA). MDA bound to TBA (MDA-TBA) was specifically analyzed by high-performance liquid chromatography (HPLC) (excitation, 525 nm; emission, 551 nm) using phosphate-buffered methanol as eluent.

RESULTS: No significant laser-induced MDA alteration was found in either the aqueous or the lens. The microkeratome group, however, had two to three times higher MDA levels in the lenses than the control group (p = 0.12) or the PRK (p = 0.03) group.

CONCLUSION: Elevation of MDA in the lens of the microkeratome group indicates that LASIK, but not PRK, may be a risk factor in cataractogenesis. The increased MDA levels in the LASIK group are probably caused by the microkeratome incision rather than the secondary radiation of the excimer laser. Postoperative inflammation may explain the surprising results.

Exp Eye Res 1994 Apr;58(4):453-7
ArF 193 nm excimer laser corneal surgery as a possible risk factor in cataractogenesis.
Costagliola C, Balestrieri P, Fioretti F, Frunzio S, Rinaldi M, Scibelli G, Sebastiani A, Rinaldi E.
Eye Clinic, 1st School of Medicine, Federico II University, Naples, Italy.

It was evaluated whether ArF 193 nm excimer laser corneal surgery represents a risk factor in cataractogenesis. For this purpose, 20 male albino rabbits underwent a photorefractive keratectomy and biochemical analyses on aqueous humour (hydrogen peroxide, ascorbic acid, and reduced and oxidized glutathione) and on lens (malondialdehyde, reduced and oxidized glutathione) were performed. In the aqueous humour of all treated animals a significant increase in hydrogen peroxide and in oxidized glutathione and a concomitant decrease in ascorbic acid and reduced glutathione concentration were observed. Moreover, all these variations were significantly correlated with the cumulative UV dose used. In the lens, after excimer laser corneal surgery, there was a dramatic loss of reduced glutathione and a parallel increase in oxidized glutathione levels. Malondialdehyde concentration was also increased, but only at the highest UV exposure. Moreover, all these variations were significantly correlated with the cumulative UV dose used. These findings demonstrate that the exposure of aqueous humour and lens to the secondary radiation generated after ArF 193 nm excimer laser corneal photoablative keratectomy induces biochemical modifications which are known to be markers of cataractogenesis.

Lasers Surg Med 1994;14(2):168-77
Books ArF-excimer laser-induced secondary radiation in photoablation of biological tissue.
Lubatschowski H, Kermani O, Otten C, Haller A, Schmiedt KC, Ertmer W. Institut fur Angewandte Physik, Universitat Bonn, Germany.

Secondary radiation, emitted during and after the irradiation of corneal, dermal, and dental tissue by an ArF-excimer laser (193 nm), was qualitatively and quantitatively characterized. Emission of secondary radiation was found in the range of 200-800 nm. The intensity of secondary radiation in the range of 200-315 nm (UVC and UVB) is approximately 20% of the total intensity at high laser fluences (> 2 J/cm2), and approximately 50% at moderate laser fluences ( 5 J/cm2) are required. As a consequence, laser-induced plasma formation can be observed. Secondary radiation can be used as a visible guide for selective removal of carious altered tissue. The data we have found might be of assistance in estimating potential hazards for future mutagenic studies in the field.

Ophthalmologe 1992 Apr;89(2):134-8
[193 nm Excimer laser photoablation of the cornea. Spectrum and transmission behavior of secondary irradiation].
Lubatschowski H, Kermani O. Institut fur Angewandte Physik, Universitat Bonn.

In order to estimate the photomutagenic and phototoxic potential involved we analyzed the spectrum and intensity of secondary radiation induced with a 193 nm excimer laser in photoablation of corneal tissue. The spectrum of secondary radiation was analyzed by an optical multichannel analyzer. A pyroelectrical detector was used to evaluate the energy of the secondary radiation. We found the secondary radiation to be in the range of ultraviolet to infrared. The spectrum has a relatively high quantity (20%) of radiation between 240 and 280 nm. The intensity of the secondary radiation depends on the energy fluence of the primary laser pulse and can reach a quantum yield of up to 10(-3) (at 800 mJ/cm2). At a fluence of 230 mJ/cm2 (193 nm), the secondary radiation in the range of 240-280 nm is approximately 5 microJ/cm2. Radiation below 300 nm was not transmitted through the cornea. Since the high genetic activity of UV radiation in the range from 240-280 nm is well known, evaluation of the potential mutagenicity of 193 nm excimer laser radiation should take into consideration the presence of secondary radiation in this problematic spectral range. However, there is no incidence known for specific UV-induced corneal cancers, which supports the argument that the potential mutgenic risk of clinical excimer laser application can be considered to be low. Because of the full corneal absorption of radiation below 300 nm, there is no risk known for pigmented intraocular structures.

Fortschr Ophthalmol 1991;88(4):377-9
[Induction of chromosome aberrations in human lymphocytes as a model for evaluating the mutagenic effect of excimer laser irradiation in ophthalmology].
Forster W, Emmerich KH, Busse H, Scheid W, Weber J, Traut H. Universitats-Augenklinik, Munster, Bundesrepublik Deutschland.

A model for testing the mutagenicity of excimer laser radiation in ophthalmology is presented. In contrast to other studies using cell monolayers, in our study with this model human peripheral lymphocytes (heparinized whole blood) are exposed to laser irradiation at different conditions. The possible mutagenicity of secondary radiation after exposure of the cornea is also considered. The heparinized blood is either injected into the anterior chamber of an enucleated bovine eye or filled into a quartz chamber (positive control). After irradiation the lymphocytes are stimulated and fixed during metaphase, after which the metaphases are scored for chromatid and chromosome aberrations. In the positive control group, exposure to 248 nm excimer laser radiation (500 J, 277 mJ/cm2, 10 and 20 Hz) was followed by a highly significant increase in the yield of chromatid aberrations (chromatid breaks and achromatic lesions).

Graefes Arch Clin Exp Ophthalmol 1988;226(3):273-6
Side effects in excimer corneal surgery. DNA damage as a result of 193 nm excimer laser radiation.
Seiler T, Bende T, Winckler K, Wollensak J. Universitatsaugenklinik im Klinikum Charlottenburg, Berlin.

UV radiation is known to cause actinic damage to the DNA. Excimer laser light, possibly used for keratorefractive surgery, should not produce this damage, as the penetration depth is far less than the diameter of a cell. However, photoreactivation experiments with yeast cells show a significant amount of DNA repair after excimer irradiation. The zone of influence of a small slitlike exposure has a diameter of 2 cm. Consequently, the limbus, the critical location of epithelial neoplasia, always lies within the sphere of actinic damage. Radiation damage is induced by secondary radiation rather than by direct interaction.