Sir Nicholas Harold Ridley. He changed the world, so that we might better see it

Cataract surgery with intraocular lens (IOL) implantation has become the most common and most successful of all operations in medicine. Sir Harold Ridley's first cataract extraction with implantation of an IOL marked the beginning of a major change in the practice of ophthalmology. Millions of patients worldwide have benefited from Sir Ridley's invention, and are likely to continue to derive benefit from this device. However, the development of the IOL was not without its share of ups and downs. Sir Harold Ridley, the inventor of IOL, died at the age of 94, on 25 May 2001, and ophthalmology lost one of its greatest and most influential practitioners. We are happy that he lived to enjoy the fruits of his labour--to see the amazing improvements and the expansive growth that evolved in the cataract-IOL technique, from early and unsatisfactory operations in previous decades, to the superb results attainable today. The invention of the IOL has not been just the addition of one new form of treatment, but rather, Sir Harold's tiny disc-shaped sliver of plastic has changed the world so that our patients may better see it. This article presents a brief biographical sketch of Sir Harold and lists his major inventions and contributions to ophthalmology.

Implantation of a single-piece, hydrophilic, acrylic, minus-power foldable posterior chamber intraocular lens in a rabbit model: clinicopathologic study of posterior capsule opacification

PURPOSE

To compare the extent of posterior capsule opacification (PCO) after implantation of a standard-power biconvex Centerflex intraocular lens (IOL) and a newly introduced biconcave high-minus-power Centerflex design in rabbit eyes.

SETTING

The Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, and the David J. Apple, MD, Laboratories for Ophthalmic Devices Research, John A. Moran Eye Center, University of Utah School of Medicine, Salt Lake City, Utah, USA.

METHODS

Twelve rabbits had phacoemulsification and implantation of 2 foldable single-piece hydrophilic acrylic Centerflex posterior chamber IOLs. The right eyes received a standard-power (+21.00 diopters [D]) biconvex-optic lens and the left eyes, a minus-power (-7.00 D) biconcave-optic IOL. Formation of PCO was evaluated 3 weeks after surgery using the Miyake-Apple posterior photography technique. Histological sections from each globe were prepared to analyze capsular bag status and assess postsurgical intracapsular lens epithelial cell (LEC) proliferation, especially ingrowth of LECs across the visual axis. The data were analyzed using the Kruskal-Wallis 1-way analysis of variance for nonparametric measurements and the Mann-Whitney rank sum test.

RESULTS

There was no significant difference in Soemmering's ring formation between the 2 IOL models. The biconcave minus-power IOL showed significantly lower central and peripheral PCO scores than the biconvex standard-power lens (P<.05). Pathological evaluations revealed that the effective site of blockage of LECs was at the truncated optic edge of both lenses, even in the presence of retained and/or regenerative cortical material.

CONCLUSIONS

This study confirms the efficacy of a truncated IOL optic in helping reduce the incidence of PCO. Both IOL designs have optic geometries that create clear-cut barrier effects. However, the biconcave minus-power IOL, which has a thicker, square, truncated optic edge with a ridge that encircles the periphery of the optic for 360 degrees, appears to have an enhanced barrier effect, especially at the optic-haptic junction. This further minimizes the ingrowth of migrating LECs toward the visual axis.

Selective and specific targeting of lens epithelial cells during cataract surgery using sealed- capsule irrigation

We describe the technique of sealed capsule irrigation, which aims to reduce posterior capsule opacification and better control lens epithelial cell activity.

Opacification of two hydrophilic acrylic intraocular lenses 3 months after implantation

BACKGROUND AND OBJECTIVE

To report clinical, pathologic, histochemical, ultrastructural, and spectrographic analyses of explanted hydrophilic acrylic intraocular lenses (IOLs) obtained from two patients who had early visual disturbances caused by postoperative opacification of the lens optic.

MATERIALS AND METHODS

Two hydrophilic IOLs were explanted from patients with decreased visual acuity. The patients became symptomatic 3 months after uneventful phacoemulsification and lens implantation. IOL optic opacification was associated with a fine granularity within the substance of the lens optic. The IOLs were examined by gross and light microscopy. Full-thickness cut sections of the optics were stained with 1% alizarin red (a special stain for calcium). Some sections were submitted for scanning electron microscopy and energy dispersive x-ray spectroscopy.

RESULTS

Microscopic analyses revealed the presence of multiple fine, granular deposits of variable sizes within the optics of the lenses distributed in a line parallel to the anterior and posterior curvatures of the optic, with a clear zone just beneath the optics' surface. Extension of the opacification into the haptics of the IOLs could also be observed. The deposits stained positive with alizarin red. Energy dispersive x-ray spectroscopy of the internal substance of the IOLs also demonstrated the presence of calcium within the deposits.

CONCLUSIONS

This is the first clinicopathologic report of optic and haptic opacification occurring with this hydrophilic acrylic IOL model only 3 months postoperatively. Further studies on other similar cases with this lens should be done to determine the incidence and possible mechanisms of this phenomenon.

Calcification of modern foldable hydrogel intraocular lens designs

PURPOSE

To report and compare clinical and pathological features of hydrophilic acrylic intraocular lenses (IOLs) of three major designs, explanted from patients who had visual disturbances caused by opacification of the lens optic.

METHODS

Eighty-seven hydrophilic acrylic IOLs (25 Hydroview, 54 SC60B-OUV, and 8 Aqua-Sense lenses) were explanted and sent to our center. Most patients became symptomatic during the second year after cataract surgery. A fine granularity was observed on the surface of the lens optic in the case of Hydroview. With the SC60B-OUV and Aqua-Sense lenses, the opacity resembled a nuclear cataract. Gross examination, light microscopy and staining with alizarin red and the von Kossa method (for calcium) were performed. Some lenses were submitted for scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS).

RESULTS

Light microscopic and SEM analyses revealed the presence of irregular granular deposits on the external optical surfaces of Hydroview lenses. With the SC60B-OUV lenses, the opacity was caused by the presence of multiple fine, granular deposits within the lens optic, distributed in a line parallel to the anterior and posterior curvatures of the optic, with a clear zone just beneath its external surfaces. The Aqua-Sense lenses exhibited both patterns simultaneously. The deposits in all cases stained positive with alizarin red and von Kossa method. EDS also demonstrated the presence of calcium and phosphates within the deposits.

CONCLUSION

Differences in the water content of the hydrophilic acrylic materials used in the manufacture of these three lens designs may be responsible for the different patterns of calcium precipitation. Careful clinical follow up of patients implanted with these lenses is necessary to determine if this phenomenon is rare and sporadic or may be more widespread.

Viscoanesthesia. Part I: toxicity to corneal endothelial cells in a rabbit model

PURPOSE

To evaluate the toxicity of a solution combining sodium hyaluronate 1.5% with lidocaine (0.5%, 1.0%, or 1.65%) to the rabbit corneal endothelium.

SETTING

Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.

METHODS

Each rabbit cornea was excised, and the endothelium was exposed to 1 of the following solutions for 20 minutes: viscoanesthetic solution (0.5%, 1.0%, or 1.65% lidocaine in sodium hyaluronate 1.5%; 5 corneas each), sodium hyaluronate 1.5% (n = 5), balanced salt solution (BSS(R)) (n = 5), mitomycin-C 0.02% (n = 2), dextran 15% (n = 2), or distilled water (n = 2). The endothelium was then stained with trypan blue and alizarin red. Two corneas were stained immediately after excision. Cell morphology and damage to the corneal endothelium were analyzed by microscopic examination.

RESULTS

The endothelium in the corneas of the viscoanesthetic groups was comparable to that in the sodium hyaluronate 1.5% and the BSS groups and to the corneas not exposed to any solution. In some areas of the 1.0% and the 1.65% viscoanesthesia groups, the corneal endothelial cells presented irregular intercellular borders. Staining with trypan blue, which indicates cellular damage, was observed in some linear areas corresponding to corneal folds in all groups. The folds were probably caused during manipulation for corneal excision and staining. The corneal endothelium was destroyed in the mitomycin group. In the dextran and distilled-water groups, morphological alterations probably resulting from osmotic changes were observed.

CONCLUSIONS

The 3 concentrations of viscoanesthetic solutions appeared to be safe to rabbit corneal endothelium.

Retrospective evaluation of intraocular lenses in adults younger than 60 years

Data from the U.S. Food and Drug Administration, the American Academy of Ophthalmology's National Eyecare Outcomes Network, and Storm Eye Institute databases were analyzed for short- and long-term safety and efficacy outcomes of intraocular lens (IOL) implantation in adults younger than 60 years and 60 years and older. Statistical analyses for significance were performed where appropriate. A comprehensive literature review was conducted to identify safety and efficacy outcomes and their relationship to patient age at the time of implantation. Analyses established that the performance of IOLs in adults younger than 60 years was comparable to that in adults older than 60 years and supported the use of IOLs in the younger adult population.

Viscoanesthesia. Part III: removal time of OVD/viscoanesthetic solutions from the capsular bag of postmortem human eyes

PURPOSE

To investigate and evaluate the removal time of various ophthalmic viscosurgical device (OVD)/viscoanesthetic solutions containing sodium hyaluronate 1.5% with different concentrations of lidocaine (0.5%, 1.0%, and 1.65%).

SETTING

Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.

METHODS

Six postmortem human eyes were prepared per the Miyake-Apple posterior video technique. Capsulorhexis, hydrodissection/delineation, and nuclear emulsification were performed, followed by thorough cleaning of the capsular bag using an irrigation/aspiration (I/A) tip. The time and ease of removal of 4 solutions from the capsular bag were evaluated. The solutions were Ophthalin Plus (sodium hyaluronate, 15 mg/mL) and sodium hyaluronate 15 mg/mL mixed with lidocaine 0.5%, lidocaine 1.0%, and lidocaine 1.65%. The solutions were dyed with fluorescein to enhance visualization. After the capsular bag was filled with 1 of the solutions, a posterior chamber intraocular lens was implanted. The solution was then aspirated using an automated I/A device set at 250 mm Hg of aspiration. The time required to remove most and then all the material was recorded.

RESULTS

The mean time required for removal of most of the Ophthalin Plus, viscoanesthesia 0.5%, viscoanesthesia 1%, and viscoanesthesia 1.65% solutions was 8.7 seconds +/- 2.1 (SD), 7.7 +/- 1.1 seconds, 9.7 +/- 0.6 seconds, and 6.3 +/- 1.5 seconds, respectively (P =.1). The mean time to remove all the solutions was 21.3 +/- 3.2 seconds, 19.7 +/- 2.5 seconds, 18.3 +/- 3.2 seconds, and 15.7 +/- 2.1 seconds, respectively (P =.166). No subjective difference in viscosity or consistency was found among the solutions.

CONCLUSIONS

The addition of lidocaine to the OVD solution did not significantly alter the viscosity or consistency of the solution or change its removal time from the capsular bag.

Viscoanesthesia. Part II: toxicity to intraocular structures after phacoemulsification in a rabbit model

PURPOSE

To investigate the toxicity of a solution that combines sodium hyaluronate 1.5% with lidocaine (0.5%, 1.0%, or 1.65%) to intraocular structures.

SETTING

Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.

METHODS

Phacoemulsification was performed in both eyes of 29 rabbits. They were divided into 3 groups; in each group (n = 7), 1 viscoanesthetic solution was used before capsulorhexis. After irrigation/aspiration, 0.2 mL of the solution was purposely left in the capsular bag. In 1 rabbit in each group, the solution was injected into the vitreous cavity through a posterior capsulorhexis. In 8 rabbits used as controls, balanced salt solution (BSS(R)) (n = 4) or sodium hyaluronate 1.5% (n = 4) was injected into the vitreous cavity. Enucleations were performed 15, 30, and 60 days postoperatively. Histological sections were cut and stained with hematoxylin-eosin, periodic acid-Schiff, and Masson trichrome stains.

RESULTS

Light microscopic evaluation of the eyes enucleated after 15, 30, and 60 days in the study and control groups showed similar findings in intraocular structures such as the ciliary body and retina. No evidence of an inflammatory reaction, cell necrosis, or cell degeneration was observed in the histological sections.

CONCLUSIONS

The use of viscoanesthesia during phacoemulsification appeared to be safe, with no histologic abnormalities observed with the 3 lidocaine concentrations. The efficacy of the anesthetic effects of these solutions will be addressed in clinical trials.

[Techniques for preparing postmortem human eyes to perform anterior segment intraocular surgery]

We describe different methods to prepare postmortem human or animal eyes used at the Center for Research in Ocular Therapeutics and Biodevices at the Storm Eye Institute, Medical University of South Carolina, Charleston, SC, USA. These techniques have been utilized for performing different surgical procedures (phacoemulsification, extracapsular cataract extraction, etc.), and for training of surgeons in-transition. Performing these techniques in the wet-laboratory contributed to improve surgical skills to perform the critical steps of the phacoemulsification surgery. Pathological evaluation of pseudophakic postmortem human eyes using the Miyake-Apple posterior view and histology was helpful to analyze postoperative complications of cataract surgery (anterior capsule opacification and posterior capsule opacification) secondary to postoperative proliferation of lens epithelial cells into the capsular bag. Modifications in the surgical techniques and/or lens design may be helpful to reduce these postoperative complications. Implantation of various aphakic and phakic intraocular lenses in postmortem human eyes as well as animal eyes was helpful to analyze the sizing and fitting of new lens designs within the eye.

Paediatric cataract blindness in the developing world: surgical techniques and intraocular lenses in the new millennium

Paediatric cataract blindness presents an enormous problem to developing countries in terms of human morbidity, economic loss, and social burden. Managing cataracts in children remains a challenge: treatment is often difficult, tedious, and requires a dedicated team effort. To assure the best long term outcome for cataract blind children, appropriate paediatric surgical techniques need to be defined and adopted by ophthalmic surgeons of developing countries. The high cost of operative equipment and the uneven world distribution of ophthalmologists, paediatricians, and anaesthetists create unique challenges. This review focuses on issues related to paediatric cataract management that are appropriate and suitable for ophthalmic surgeons in the developing world. Practical guidelines and recommendations have also been provided for ophthalmic surgeons and health planners dealing with childhood cataract management in the developing world.

Scanning electron microscopic and histologic evaluation of the AcrySof SA30AL acrylic intraocular lens. Manufacturing quality and morphology in the capsular bag

PURPOSE

To evaluate the properties of the AcrySof(R) SA30AL (Alcon Laboratories, Inc.) single-piece foldable posterior chamber intraocular lens (IOL).

SETTING

Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.

METHODS

Two nonimplanted clinical-quality AcrySof IOLs were examined by gross, light, and scanning electron microscopy (SEM). In addition, 2 eyes implanted with this IOL obtained post-mortem, the first such eyes accessioned in our laboratory and the first described to date, were examined using the Miyake-Apple posterior photographic technique and by histologic sections.

RESULTS

Scanning electron microscopy of the SA30AL IOL showed excellent surface finish. The edge of the optic was square (truncated) and had a matte (velvet or ground-glass) appearance, a feature that may minimize edge glare and other visual phenomena. A well-fabricated square or truncated optic edge was demonstrated. Miyake-Apple analysis revealed that the SA30AL IOL showed appropriate fit and configuration within the capsular bag. Histologic correlation of the IOL's square edge and its relation to the capsular bag and adjacent Soemmering's ring were noted.

CONCLUSIONS

The AcrySof SA30AL IOL is a well-fabricated lens that situates well in the capsular bag. The truncated optic and its relationship to adjacent structures show a morphological profile that has been shown to be highly efficacious in reducing the rate of posterior capsule opacification.

Silicone plate-haptic posterior chamber intraocular lens implanted in the anterior chamber: report of a bilateral case and potential complications

BACKGROUND AND OBJECTIVE

To evaluate possible complications associated with implantation of a posterior chamber (PC) intraocular lens (IOL) in the anterior chamber.

MATERIALS AND METHODS

We analyzed a plate-haptic silicone IOL that had been explanted from the anterior chamber of an 83-year-old female. Additionally, the lens was experimentally reimplanted into the anterior chambers of 3 human cadaver eyes. After fixation of the eyes (Karnovsky's solution), the anterior-posterior length, the white-to-white diameter, the angle-to-angle diameter, and the sulcus-to-sulcus diameter were measured. Two different techniques to cut the eyes were used: sagittal section and corneal buttonhole technique. The plate-haptic silicone lens was then implanted in the anterior chamber and sulcus ciliaris of the eyes. A Kelman multiflex IOL was used as a control for anterior chamber implantation.

RESULTS

This experiment demonstrated that the plate-haptic silicone IOL lens is too small and thick for implantation in the anterior chamber and in the sulcus. The lens could easily rotate in the anterior chamber and also dislocate inferiorly, obstructing the visual axis by its edge. The thickness of the lens theoretically could also cause endothelial cell damage and mechanical iris irritation resulting in chronic uveal inflammation.

CONCLUSION

This case and experiment should help surgeons realize the risk and potential for IOL-missizing complications that may be caused if a lens design for the capsular bag is implanted in the anterior chamber, especially if a plate-haptic PC-IOL design is used.

Hydrophilic acrylic intraocular lens optic and haptics opacification in a diabetic patient: bilateral case report and clinicopathologic correlation

OBJECTIVE

To report clinicopathologic and ultrastructural features of two opacified single-piece hydrophilic acrylic intraocular lenses (IOLs) explanted from a diabetic patient.

DESIGN

Interventional case report with clinicopathologic correlation.

SETTING

A 64-year-old white female underwent phacoemulsification and implantation of a single-piece hydrophilic acrylic lens (SC60B-OUV; Medical Developmental Research, Inc., Clear Water, FL) in October 1998 in the left eye and in July 1999 in the right eye. The best-corrected visual acuity after surgery was 20/60 in the left eye and 20/50 in the right eye. The patient had a marked decrease in visual acuity in June 2000 as a result of a milky, white opalescence of both lenses. Intraocular lens explantation and exchange was performed in both eyes and the explanted IOLs were submitted to our center for detailed pathologic, histochemical, and ultrastructural evaluation. They were stained with alizarin red and the von Kossa method for calcium, and also underwent scanning electron microscopy and energy dispersive radiograph spectroscopy to ascertain the nature of the deposits leading to opacification.

MAIN OUTCOME MEASURES

Documentation of calcium deposits confirmed by histochemical stains and surface analyses.

RESULTS

Opacification of the IOL was found to be the cause of decreased visual acuity. The opacification involved both the IOL optic and the haptics in the left eye and was confined to the IOL optic in the right eye. Histochemical and ultrastructural analyses revealed that the opacity was caused by deposition of calcium and phosphate within the lens optic and haptics.

CONCLUSIONS

There are two features that distinguish this case from those reported earlier. This is the first clinicopathologic report of lens opacification that has involved completely the lens optic and the haptics. Second, these two explanted IOLs document the first bilateral case. This process of intraoptic and haptic opacification represents dystrophic calcification of unknown cause. Diabetic patients appear to be more severely and more often affected by lens opacification. Long-term follow-up of diabetic patients implanted with this IOL design should be maintained by surgeons and manufacturers.

A first comparative study of purpurinimide-based fluorinated vs. nonfluorinated photosensitizers for photodynamic therapy

A first report on the synthesis and comparative in vitro-in vivo photosensitizing efficacy of various fluorinated and the corresponding nonfluorinated, purpurinimide-based photosensitizers is discussed. In preliminary in vivo screening, compared with the nonfluorinated analogs, purpurinimides bearing trifluoromethyl substituents showed enhanced photosensitizing efficacy. Among compounds (isomers) with similar lipophilicity, the position of the substituents was found to play a decisive role in biological efficacy.

Studies on essential oils: part 10; antibacterial activity of volatile oils of some spices

The essential oils extracted from the seeds of seven spices, Anethum graveolens, Carum capticum, Coriandrum sativum, Cuminum cyminum, Foeniculum vulgare, Pimpinella anisum and Seseli indicum have been studied for antibacterial activity against eight pathogenic bacteria, causing infections in the human body. It has been found that the oil of C. capticum is very effective against all tested bacteria. The oil of C. cyminum and A. graveolens also gave similar results. These oils are equally or more effective when compared with standard antibiotics, at a very low concentration.

Effect of hydrodissection on intraoperative performance: randomized study

PURPOSE

To evaluate the effect of hydrodissection on intraoperative performance during phacoemulsification of age-related nuclear cataracts.

SETTING

Iladevi Cataract & IOL Research Centre, Ahmedabad, India, and Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.

METHODS

In a prospective study, 86 eyes were randomly assigned to have multiquadrant hydrodissection (+HD, n = 48) or no hydrodissection (-HD, n = 38) during phacoemulsification of a grade 1 to 3 nuclear cataract. Excluded were patients with grade 4 or 5 nuclear sclerosis, a poorly dilating pupil, or associated ocular/systemic disease. Parameters assessed were nucleus and cortex removal time, the amount of fluid used for cortex removal, and the total amount of fluid used. The ease of nucleus rotation and cortical cleanup was also evaluated and graded subjectively as very easy, difficult, or very difficult. Data were analyzed using the Student t test and the chi-square test.

RESULTS

The mean nucleus removal time was 355 seconds +/- 237 (SD) and 474 +/- 212 seconds in the +HD and -HD groups, respectively (P =.09). The mean cortex removal time was significantly less in the +HD group than in the -HD group (79 +/- 51 seconds and 220 +/- 222 seconds, respectively) (P =.007). Significantly less fluid (43%) was used for cortex removal in the +HD group than in the -HD group (mean 70 +/- 45 mL and 123 +/- 82 mL, respectively) (P =.013), and significantly less total fluid (35%) was used in the +HD group (312 +/- 132 mL and 422 +/- 80 mL, respectively) (P =.002). Nucleus rotation was easy in all eyes in the +HD group; 68.43% of eyes in the -HD group failed to achieve rotation (P =.001). Cortex removal was very easy in 52.08% of eyes in the +HD group and easy in 47.90%; it was easy in 52.63% in the -HD group, difficult in 36.84%, and very difficult in 10.52%.

CONCLUSION

The use of multiquadrant cortical-cleaving hydrodissection made removal of the lens nucleus and cortex easier and faster during phacoemulsification of age-related nuclear cataracts.

Evaluation of 3 modern single-piece foldable intraocular lenses: clinicopathological study of posterior capsule opacification in a rabbit model

PURPOSE

To assess the development of posterior capsule opacification (PCO) with 3 modern single-piece foldable intraocular lenses (IOLs) in a histopathological study and to compare the potential preventive effects of the IOL design and biomaterial in retarding PCO.

SETTING

Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.

METHODS

Thirty-one rabbit eyes were randomly operated on with phacoemulsification and implantation of 3 single-piece foldable lenses: a hydrophilic acrylic design, the Rayner Centerflex 570H (n = 11); a hydrophobic acrylic design, the Alcon AcrySof SA30AL (n = 10); and a silicone large-hole plate design, the Staar AA-4203VF (n = 10). Central PCO (CPCO), peripheral PCO (PPCO), and Soemmering's ring formation were evaluated 3 weeks after surgery using the Miyake-Apple posterior photographic technique. Histological sections of each globe were prepared to document capsular bag status and performance of IOL geometry.

RESULTS

The acrylic IOLs (Centerflex and AcrySof) had lower CPCO and PPCO scores than the silicone plate IOL (P <.05). There was no significant difference in Soemmering's ring formation among the 3 models. Pathological evaluations revealed effective blockage of migrating lens epithelial cells (LECs) at the site of the truncated optic edge of the Centerflex and AcrySof IOLs, even in the presence of large amounts of retained/regenerative cortical material.

CONCLUSIONS

The AcrySof IOL has a hydrophobic surface and the Centerflex a hydrophilic surface, but no correlation to these characteristics could be identified. The single-piece AcrySof optic geometry created a clear-cut barrier effect equal to that of its 3-piece predecessor. The anatomic profile of the Centerflex IOL shows the same characteristics. The optics of both acrylic lenses have square truncated edges that functionally block ingrowth of migrating LECs toward the central visual axis, leaving clear posterior capsules. The square optic edge was an appropriate geometric configuration to create a barrier effect. There was no effect of the biomaterial on PCO prevention.

Permanent blue discoloration of a hydrogel intraocular lens by intraoperative trypan blue

A 79-year-old white man had cataract surgery in the right eye with implantation of an Acqua intraocular lens (IOL) (Mediphacos). Trypan blue 0.1% was used during surgery to stain the anterior capsule and enhance the contrast during capsulorhexis. Seven days after surgery, the patient presented with "dark and double" vision (monocular diplopia). The IOL was decentered superiorly and appeared dark blue. The lens was explanted 2 months after surgery and sent for gross and microscopic analyses in a dry state and after hydration. The same analyses were performed on 2 unused lenses of the same design that had been immersed in diluted trypan blue solutions (0.01% and 0.001%). On the explanted lens, the dark blue staining was denser in the optic, especially in its periphery. The blue discoloration could not be removed after 24 hours of lens immersion in a balanced salt solution at 37 degrees C. Permanent staining of the unused lenses was also obtained after immersion in the trypan blue solutions.