Long term changes in human corneal endothelium following toxic endothelial cell destruction: a specular microscopic and fluorophotometric study

Micro- and nano-topography to enhance proliferation and sustain functional markers of donor-derived primary human corneal endothelial cells

One of the most common indications for corneal transplantation is corneal endothelium dysfunction, which can lead to corneal blindness. Due to a worldwide donor cornea shortage, alternative treatments are needed, but the development of new treatment strategies relies on the successful in vitro culture of primary human corneal endothelial cells (HCECs) because transformed cell lines and animal-derived corneal endothelial cells are not desirable for therapeutic applications. Primary HCECs are non-proliferative in vivo and challenging to expand in vitro while maintaining their characteristic cell morphology and critical markers. Biochemical cues such as growth factors and small molecules have been investigated to enhance the expansion of HCECs with a limited increase in proliferation. In this study, patterned tissue culture polystyrene (TCPS) was shown to significantly enhance the expansion of HCECs. The proliferation of HCECs increased up to 2.9-fold, and the expression amount and localization of cell-cell tight junction protein Zona Occludens-1 (ZO-1) was significantly enhanced when grown on 1 μm TCPS pillars. 250 nm pillars induced an optimal hexagonal morphology of HCEC cells. Furthermore, we demonstrated that the topographical effect on tight-junction expression and cell morphology could be maintained throughout each passage, and was effectively 'remembered' by the cells. Higher amount of tight-junction protein expression was maintained at cell junctions when topographic cues were removed in the successive seeding. This topographic memory suggested topography-exposed/induced cells would maintain the enhanced functional markers, which would be useful in cell-therapy based approaches to enable the in situ endothelial cell monolayer formation upon delivery. The development of patterned TCPS culture platforms could significantly benefit those researching human corneal endothelial cell cultivation for cell therapy, and tissue engineering applications.

Characterization of porcine corneal endothelium for xenotransplantation

PURPOSE

Endothelial keratoplasty (EKP) has become increasingly popular in the treatment of corneal disease. However, the global shortage of human donor corneas limits clinical corneal transplantation. Genetically engineered (GE) pigs may provide an alternative source of corneas for EKP. The aim of this study was to evaluate corneal endothelial cells (CECs) from wild-type (WT) and GE pigs.

METHODS

Density, size of CECs, and the percentage of hexagonal cells (as a measure of heterogeneity) were measured by ex vivo confocal microscopy in corneas from WT and GE pigs of different ages - neonatal (4-5 days), young (5-15 weeks), adult (5-15 months), and old (20-42 months). α1,3-galactosyltransferase gene-knockout (GTKO) pigs transgenic for the human complement-regulatory protein(s), CD46 (GTKO/CD46) +/- CD55 (GTKO/CD46/CD55) were used as sources of GE corneas.

RESULTS

Mean CEC densities (cells/mm²) were neonatal (5968), young (3789), adult (2589), and old (2070). As with human corneas, there was an age-dependent decrease in pig CEC density and increase in pig CEC size. However, unlike human corneas, there was no correlation between the percentage of hexagonal cells (approximately 50% in all pig corneas) and age, suggesting that heterogeneity is intrinsic for pig corneas. Genetic modification did not affect CEC density, size, or morphology compared to WT pigs.

CONCLUSION

Because of the availability of young pigs and their greater CEC density (and the protection afforded against the human immune response), GE pigs could provide an unlimited source of corneas for clinical EKP.

Frog saliva-induced toxic keratopathy: a case report

Corneal toxicity due to exposure to many chemicals and medications have been described in the literature. We present a case of toxic keratopathy by corneal exposure to salivary secretion of a frog. A 40-year-old male patient reported a sudden splash of frog saliva in his right eye while he was examining it at a close distance. Corneal punctate epitheliopathy and stromal oedema and Descemet folds were the initial clinical findings, which completely recovered on the 2nd control day of topical dexamethasone and ofloxacin treatment. We aimed to show the toxic effects of animal-derived secretions on the cornea as a rare cause of toxic keratopathy.

Toxic anterior segment syndrome after foldable artiflex iris-fixated phakic intraocular lens implantation

Toxic anterior segment syndrome (TASS) developed in four cases after uneventful implantation of a foldable iris-fixated phakic intraocular lens (pIOL). Two cases occurred sequentially in one patient. The TASS subsided without complications in all cases after intensive topical steroid treatment. A multitude of possible causes is considered for the occurrence of these TASS cases. From the sterilization and cleaning of surgical instruments to the possibility of endotoxines in ophthalmic viscosurgical devices (OVD). These rare cases should alert the surgeon to the possibility of TASS after pIOL implantation.

Human corneal endothelial cell expansion for corneal endothelium transplantation: an overview

The monolayer of cells forming the human corneal endothelium is critical to the maintenance of corneal transparency and is not known to regenerate in vivo. Thus, dysfunction of these cells constitutes the most often cited reasons for the 150,000 or so corneal transplants performed yearly. Although current corneal transplantation is more than 90% successful at 1 year, longer term results are not as encouraging with approximately 70% success at 5 years. Nonimmunologic graft failure and allograft endothelial rejection are the main problems. Furthermore, the global shortage of donor corneas greatly restricts several corneal transplantations performed. With advances in understanding corneal endothelial cell biology, it is now possible to cultivate human corneal endothelial cells (HCECs) in vitro, thus providing new opportunities to develop novel tissue-engineered human corneal endothelium. This review will provide an overview of (a) the characteristics of human corneal endothelium; (b) past and present HCECs isolation and culture protocols; (c) various potential carriers for the generation of tissue-engineered corneal endothelium, together with some of the functional studies reported in various animal models; and (d) the current rapid advancements in surgical techniques for keratoplasty. A successful combination of tissue-engineered human corneal endothelium coupled with innovative and groundbreaking surgical procedures will bridge basic research involving cultured HCECs, bringing it from bench to bedside.

Long-term recovery of the human corneal endothelium after toxic injury by benzalkonium chloride

INTRODUCTION

The inadvertent intra-ocular administration of benzalkonium chloride-preserved hydroxypropyl methylcellulose during cataract surgery at another hospital in 1999 resulted in toxic corneal endothelial injury and profound postoperative corneal oedema as a result of endothelial decompensation. The long-term effect of this adverse event was assessed.

METHODS

All 19 patients were invited to return for examination including corneal endothelial specular microscopy and pachymetry seven years after the incident. Results were compared with data from one year after the incident.

RESULTS

Five patients attended for examination, one had received a penetrating keratoplasty and was, therefore, excluded. Ten patients had died and four had moved out of the region and were unable to attend. All four study patients were pain free and achieved 6/12 or better. Mean central corneal thickness reduced by 13% from 652.6 microm at one year to 563.4 microm. Mean central corneal endothelial cell density (n = 3) increased 28% from 663.7 cells/mm(2) at one year to 835.7 cells/mm(2) (p<0.05).

CONCLUSIONS

After toxic injury, corneal endothelial function may have a remarkable capacity for recovery even after the first postoperative year. The rise in central endothelial cell density may represent cell migration from less affected areas or cellular proliferation. Should this unfortunate event recur, clinicians may expect continued recovery beyond one year.

Outbreak of toxic anterior segment syndrome associated with glutaraldehyde after cataract surgery

PURPOSE

To present clinical findings of a cluster of cases of toxic anterior segment syndrome (TASS) after uneventful phacoemulsification cataract surgery.

SETTING

Department of Ophthalmology, Akdeniz University, Antalya, Turkey.

METHODS

Six eyes of 6 patients developed TASS after uneventful phacoemulsification cataract surgery with implantation of a 3-piece acrylic IOL performed by 2 ophthalmologists on the same day. Clinical findings included corneal edema, Descemet's membrane folds, anterior chamber reaction, fibrin formation, and irregular, dilated, and unreactive pupils.

RESULTS

Glutaraldehyde 2% solution was used inadvertently by the operating room staff who cleaned and sterilized reusable ocular instruments before autoclaving. None of the affected corneas improved. Additional surgical procedures were required and included penetrating keratoplasty, trabeculectomy, and glaucoma tube implantation.

CONCLUSIONS

Glutaraldehyde in concentrations generally used for cold sterilization is highly toxic to the corneal endothelium. The operating room staff involved in sterilizing instruments should be well educated about and careful to follow the protocols to properly clean and sterilize reusable ocular instruments.

Three-Year Follow-up Analysis of Artisan Toric Lens Implantation for Correction of Postkeratoplasty Ametropia in Phakic and Pseudophakic Eyes

PURPOSE

To determine the 3-year follow-up of efficacy and safety of Artisan toric iris-fixated lens implantation after penetrating keratoplasty (PK) to correct high ametropia and astigmatism.

DESIGN

Prospective noncomparative case series with a minimum follow-up of 1 year.

PARTICIPANTS

Artisan toric lens implantation was performed in 36 eyes of 35 patients who were contact lens intolerant or unable to wear glasses due to anisometropia and/or high astigmatism.

INTERVENTION

Thirty-six eyes of 35 consecutive patients received Artisan toric lens implantation for postkeratoplasty astigmatism and/or anisometropia.

MAIN OUTCOME MEASURES

Manifest refraction, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and corneal topography were determined or performed before surgery and at 3, 6, and 12 months and yearly intervals up to 4 years after surgery. Efficacy, safety, percent reduction of refractive astigmatism, anisometropia of defocus, and the astigmatism correction index were determined. A patient satisfaction questionnaire and specular microscopy were assessed.

RESULTS

The mean +/- standard deviation of preoperative refractive cylinder was -7.06+/-2.01 diopters (D) (range, -3.0 to -11.0), which was reduced to -1.73+/-1.25 D, -1.69+/-1.15 D, -1.94+/-1.68 D, -2.02+/-1.93 D, and -2.00+/-1.53 D at 6 months (n = 36), 1 year (n = 36), 2 years (n = 29), 3 years (n = 15), and the last follow-up examination (28.5+/-12.5 months, n = 36), respectively (P<0.001 for all time points, paired t test). The spherical equivalent was reduced from -3.19+/-4.31 D (range, +5.5 to -14.25 D) preoperatively to -1.03+/-1.20 D (range, +1.0 to -5.25 D) at the last follow-up. The UCVA and BSCVA were > or =20/40 in 31.6% and 80.6%, respectively. There was a loss of BSCVA of >2 lines in 8.3% of eyes and a gain of at least 2 lines in 8.3% of eyes. Percent reductions in refractive astigmatism and anisometropia of defocus were 88.8%+/-29.5% and 77.8%+/-19.3%, respectively. The astigmatism correction index was 96.0%+/-24.2%. Satisfaction increased from 3.6 to 8.0 (scale, 0-10) after implantation. The endothelial cell loss as compared with preoperatively was 13.8%+/-18.7% (n = 34), 21.2%+/-21.8% (n = 33), 29.6%+/-27.3% (n = 26), 30.4%+/-32.0% (n = 18), and 34.8%+/-26.3% (n = 6) at 6 months (P = 0.001), 1 year (P<0.001), 2 years (P<0.001), 3 years (P = 0.001), and 4 years postoperatively (P = 0.1), respectively. In 2 patients, irreversible graft rejections occurred, and in 1 patient, gradual endothelial decompensation occurred.

CONCLUSION

Artisan toric lens implantation after PK was effective for reduction of refractive astigmatism and ametropia. All patients were suitable for spectacle correction after implantation. There was continuing endothelial cell loss from 6 months to 3 years postoperatively. In 3 cases, corneal graft failure developed.

An outbreak of endophthalmitis after extracapsular cataract surgery probably caused by endotoxin contaminated distilled water used to dissolve acetylcholine

AIM

To study possible causes of an outbreak of severe endophthalmitis after planned extracapsular cataract surgery in Medan, Indonesia.

METHODS

In a 3 week period in November 2001, 17 of 43 patients developed signs of endophthalmitis after planned extracapsular cataract surgery. A search for possible causes was undertaken 4 months later.

RESULTS

In autoclaved stored distilled water used to dissolve acetylcholine (used in 16 of 17 patients with endophthalmitis) a high amount of endotoxin was detected in a human blood essay, as well as a small number of non-typeable Pseudomonas spp.

CONCLUSIONS

These findings suggest that distilled water used as solvent for acetylcholine was responsible for this outbreak of endophthalmitis. As a consequence, we now rely on solvents that are regularly checked for impurities such as an intravenous infusion fluid, rather than on vials with distilled water that is presumed to be sterile and kept for some time.

Corneal injury by anti-misting agent in swim goggles: a case report

PURPOSE

To report a case of corneal injury by swim goggle anti-misting agent.

METHODS

Case report.

RESULTS

A 47-year-old man presented with ocular injury caused by swim goggle anti-misting agent. Two weeks previously, the patient felt sudden ocular pain and grit after pool water flooded his goggles while swimming. Before the patient's swim, a copious amount of anti-misting agent was sprayed inside his goggles. On examination, severe corneal epithelial defect and stroma edema of the right eye were noted. Best-corrected visual acuity (BCVA) was 20/40. Right eye corneal thickness was 625 microm. Topical corticosteroids, antibiotic eye drops, and oral tetracycline were started. After 1 week of treatment, the epithelial defect of his right cornea improved slightly. Stromal edema decreased mildly. Epithelial defect persisted at 1 month follow-up. Right eye BCVA remained 20/40. Three months after treatment, the right eye epithelial defect healed completely. Mild diffuse superficial stromal opacity was noted. BCVA improved to 20/20. At 1-year follow-up, right eye corneal thickness was 547 microm, which was thinner than the left eye. Right eye corneal endothelial cell density measured approximately 1500 cells/mm2, which was less than the left eye at 2300 cells/mm2. The faint, diffuse stromal opacity disappeared; however, white subepithelial plaques were noted in the cornea centers. After 1 month of treatment with topical corticosteroids, the plaques subsided completely. The corneas remained clear at 2-year follow-up.

CONCLUSION

Anti-misting agent can cause severe corneal injuries, including persistent epithelial defects, stromal edema and opacity, endothelial cell loss, and subepithelial plaque.

Corneal toxicity secondary to inadvertent use of benzalkonium chloride preserved viscoelastic material in cataract surgery

AIMS

To study the long term toxic effects of intraocular benzalkonium chloride (BAC).

METHODS

19 patients exposed to intraocular BAC preserved viscoelastic during cataract surgery in February 1999 developed severe striate keratopathy immediately postoperatively. 16 patients, including two who underwent penetrating keratoplasty, were studied in the period April to June 2000. Ocular symptoms, visual acuity, biomicroscopy, intraocular pressure, dilated funduscopy, specular endothelial microscopy, and corneal pachymetry findings were recorded. The corneal and iris specimens of the two patients who underwent keratoplasty were studied by light, transmission, and scanning electron microscopy.

RESULTS

Six males and 10 females, aged 64-98 years, were studied 14-16 months postoperatively. All patients were symptomatic. 12 patients had best corrected visual acuity of 6/12 or better and four patients of between 6/18 and 6/60. Five patients had corneal epithelial oedema and 11 had Descemet's membrane folds. The central corneal thickness, 620 (SD 71) microm, in affected eyes was significantly higher (p<0.005, two tailed paired t test) than that of the contralateral eyes, 563 (SD 48) microm. The endothelial cell density was significantly lower (p<0.0001, two tailed paired t test) in affected eyes: 830 (SD 280) cells/mm2 v 2017 (SD 446) cells/mm2. The mean average cell area was significantly higher in the BAC treated eyes: 1317 (SD 385) microm2 v 521 (SD 132) microm2. There was no significant difference in the coefficient of variation of cell size between the two eyes (p=0.3, two tailed paired t test). Two corneal specimens displayed morphological features of bullous keratopathy and other non-specific abnormalities. Extracellular melanosomes were present in a portion of the iris of one case.

CONCLUSION

BAC is toxic to the corneal endothelium when used intraocularly, leading to severe striate keratopathy. This cleared in most cases but left varying degrees of residual stromal thickening in all eyes. If penetrating keratoplasty is required the results are excellent.

Toxic endothelial cell destruction from intraocular benzalkonium chloride

PURPOSE

To present a cluster of cases of corneal edema occurring after phacoemulsification.

SETTING

Regional hospital in rural Australia.

METHODS

This retrospective case series comprised 12 patients from a single surgical list comprising 19 cases who developed persistent corneal edema after having phacoemulsification.

RESULTS

After 6 months, the edema improved in 1 patient. Inadvertent intraocular use of balanced salt solution (BSS) preserved with benzalkonium chloride was found to be the cause of this serious complication.

CONCLUSIONS

Benzalkonium chloride in concentrations commonly used extraocularly is highly toxic to the corneal endothelium. Every possible safeguard should be taken to prevent inadvertent intraocular use of such preserved solutions.

Intraocular lidocaine in phacoemulsification: an endothelium and blood-aqueous barrier permeability study

OBJECTIVE

To evaluate the effects of intraocular lidocaine hydrochloride (HCI) on the corneal endothelium and of blood-aqueous barrier (BAB) permeability in ultrasound phacoemulsification.

DESIGN

Nonrandomized, comparative trial.

PARTICIPANTS

Sixty patients who underwent uneventful, single-surgeon, clear cornea phacoemulsification were studied prospectively.

METHODS

Sub-Tenon's anesthesia was administered to 30 patients (group 1), and intraocular lidocaine hydrochloride was administered to an additional 30 patients (group 2). An endothelial study of at least 120 cells per patient, using a noncontact specular microscope and a digital image analysis system, was performed before surgery and 1 month after surgery. Blood-aqueous barrier permeability was evaluated preoperatively and postoperatively (48 hours, 1 week and 1 month) using a laser flare meter.

MAIN OUTCOME MEASURES

Endothelial parameters (cell density, hexagonality, and coefficient of variation in cell area) and BAB permeability.

RESULTS

No significant differences were found between groups when comparing the postoperative changes produced in endothelial cell density (95% confidence interval [CI], 0.46, 4.7; P = 0.10), hexagonality (95% CI, -2.5, 3.5; P = 0.72), and coefficient of variation in cell area (95% CI, -8.3, 4.6; P = 0.57). A multivariate study detected no significant differences in mean flare values between groups during follow-up (P = 0.40). No clinically significant differences were found between mean preoperative and 1 month postoperative flare values in either group.

CONCLUSIONS

The recovery of BAB permeability 1 month after surgery seems to suggest that no additional inflammation was induced by intraocular lidocaine HCI. The fact that no differences in postoperative changes in endothelial parameters were found between groups indicates that no further corneal endothelial damage (other than that caused by surgical manipulation) was incurred. According to our results, intracameral lidocaine HCI appears to be safe for the average phacoemulsification patient in the absence of ocular pathologic conditions.

The resiliency of the corneal endothelium to refractive and intraocular surgery

PURPOSE

To describe stress factors (phenylephrine and contact lenses) from the corneal epithelium that can affect the corneal endothelium, and to describe the effects of refractive and intraocular surgery on the corneal endothelial structure and function.

METHODS

Significant clinical and experimental publications are reviewed and recent experiments conducted in the author's laboratory to describe the corneal endothelial stresses.

RESULTS

The corneal epithelium serves as a barrier to topical phenylephrine (2.5-10%). In a compromised epithelium, topical phenylephrine will cause drug-induced stromal edema and endothelial vacuolization. Contact lenses are capable of stimulating the epithelial arachidonic acid cascade to release 12(R)hydroxyeicosatetraenoic acid (12(R)HETE) and 8(R)hydroxy-hexadecatrienoic acid (8(R)HHDTrE) to cause endothelial Na+/K+ adenosine triphosphatase (ATPase)-inhibition and polymegethism. Specular microscopy of the corneal endothelial cells after refractive surgery (photorefractive keratectomy [PRK], laser in situ keratomileusis [LASIK], intrastromal rings [INTACs]) has shown that there is minimal effect. However, laser ablation of the stroma within 200 microm of the corneal endothelium will result in endothelial cell structural changes and the formation of the amorphous substance deposited onto Descemet's membrane. Phacoemulsification with a high flow of the irrigation solution can alter the endothelial surface glycoprotein layer. Lidocaine hydrochloride (1%) used as intracameral anesthesia readily diffuses through the corneal endothelium, resulting in stromal uptake and endothelial cell swelling. With phacoemulsification, however, the washout of lidocaine from the cornea (T1/2, 5 minutes) and iris (T1/2, 9 minutes) occurs quickly. Corneal endothelial wound healing after keratoplasty occurs in the following sequence: migration of endothelial cells, development of tight junctions, and the formation of Na+/K+ ATPase pump sites.

CONCLUSIONS

Corneal endothelial resiliency is due to the increased peripheral endothelial cell number for migration, the ability of endothelial cells to form tight junctions to maintain the endothelial barrier, the increase in endothelial Na+/K+ ATPase pump sites under stress, and the ability of the corneal endothelial cells to shift their metabolism of glucose to the hexose monophosphate shunt for the production of nicotinamide adenine dinucleotide phosphate (NADPH) and membrane repair. All of these factors are important, along with the aqueous humor sodium concentration, which establishes the osmotic gradient for corneal deturgescence and transparency.

Human corneal thickness and its impact on intraocular pressure measures: a review and meta-analysis approach

We determined the "normal" central corneal thickness (CCT) value in human corneas based on reported literature values for within-study average CCT values, and used this as a reference to assess the reported impact of physiological variables (especially age and diurnal effects), contact lens wear, pharmaceuticals, ocular disease, and ophthalmic surgery on CCT. With the expected CCT and its variance defined, it should be possible to determine the potential impact of differences in CCT in intraocular pressure (IOP) assessments, especially by applanation tonometry, using a meta-analysis approach. Some 600 sets of CCT data were identified from the worldwide literature over the period of 1968 through mid-1999, of which 134 included IOP measures as well. The within-study average CCT values and reported variance (SD) was noted along with the number of eyes and any special characteristics, including probable ethnic origin of the study subjects. Various sets of data were subjected to statistical analyses. From 300 data sets from eyes designated as normal, the group-averaged CCT was 0.534 mm. From 230 data sets where interindividual variance was reported, the group-averaged CCT was 0.536 mm (median 0.536 mm; average SD of 0. 031 mm, average coefficient of variation = 5.8%). Overall, studies using slit-lamp-based pachometry have reported marginally lower CCT values (average 0.530 mm, average SD 0.029 mm) compared to ultrasound-based studies (average 0.544, average SD 0.034 mm), which perhaps reflects the type of individual studied (non-surgical vs. pre-surgical patients) rather than the technique itself. A slight chronological increase in reported average CCT values (approximately 0.006 mm/decade) was evident, but a substantial chronological increase was evident for ultrasound pachometry studies (approximately 0.015 mm/decade). Within the meta-analysis-generated average and variance, age had no obvious impact on CCT measures for *whites, although an age-related decline in CCT is evident for non-whites. Any diurnal effects are likely concealed within the expected variance in CCT. Contact lens wear and pharmaceuticals generally produced changes in CCT that were well within the expected variance in CCT. Of the ocular diseases, only those associated with collagen disorders (including keratoconus) or endothelial-based corneal dystrophies (e.g., Fuchs) were likely to result in decreases or increases, respectively, of CCT beyond the normal variance. Routine contact lens wear and diseases such as diabetes seem unlikely to produce changes in CCT of a magnitude that would justify pachometry as a monitoring method beyond routine slit-lamp evaluation. Increases in CCT beyond the expected variance were reported after a range of intraocular surgeries (cataract operations, penetrating keratoplasty), whereas photorefractive surgery produces a measurable decrease in CCT. A meta-analysis of possible association between CCT and IOP measures of 133 data sets, regardless of the type of eyes assessed, revealed a statistically significant correlation; a 10% difference in CCT would result in a 3. 4 +/- 0.9 mm Hg difference in IOP (P </= 0.001, r = 0.419). The observed phenomenon was much smaller for eyes designated as healthy (1.1 +/- 0.6 mm Hg for a 10% difference in CCT, P = 0.023, r = 0. 331). For eyes with chronic diseases, the change was 2.5 +/- 1.1 mm Hg for a 10% difference in CCT (P = 0.005, r = 0.450), whereas a substantial but highly variable association was seen for eyes with acute onset disease (approximately 10.0 +/- 3.1 mm Hg for a 10% difference in CCT, P = 0.004, r = 0.623). Based on the meta-analysis, normal CCT in white adults would be expected to be within +/-11.6% (+/-2 SD) of 0.535 mm, i.e., 0.473-0.597 mm (95% CI, 0.474-0.596). The impact of CCT on applanation tonometry of healthy eyes is unlikely to achieve clinical significance, but for corneas of eyes with chronic disease, pachometry should be performed if the tonometry reveals IOP readi

Detection of lens proteins in phaco tips after phacoemulsification

PURPOSE

To determine the efficacy of cleaning procedures to remove water-soluble and water-insoluble lens proteins from phaco tips after phacoemulsification.

SETTING

Academic Hospital Maastricht, Department of Ophthalmology, University Eye Clinic, and Rotterdam Hospital, Rotterdam, The Netherlands.

METHODS

Detection of alpha A-crystallins, cytoskeletal lens proteins (vimentin), and lens-cell membranes (MP26) was performed on new and reused phaco tips with specific markers. To detect antibodies, sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting techniques were used.

RESULTS

Threshold detection levels for alpha A-crystallins, vimentin, and MP26 were 100, 43, and 108 ng, respectively. No detectable residues of water-soluble or water-insoluble lens proteins were found in outflow samples of routinely cleaned phaco tips or in outflow samples of phaco tips that were not cleaned after phacoemulsification. Urea effectively eliminated water-insoluble lens proteins from contaminated phaco tips.

CONCLUSION

After regular cleaning of phaco tips, no detectable lens protein residues were found in the outflow samples. Moreover, omitting the cleaning of phaco tips after phacoemulsification did not lead to detectable lens proteins in the outflow samples.