Surface calcification of silicone plate intraocular lenses in patients with asteroid hyalosis

PURPOSE

To report three cases in which a silicone-plate lens was explanted because of whitish deposits on the posterior optic surface.

DESIGN

Observational case series with clinicopathological correlation.

PATIENTS AND METHODS

In the three instances, the deposits were observed at least 2 years after uneventful cataract surgery. All of the patients had unilateral mild asteroid hyalosis in the concerned eye. After explantation of the lenses, gross and light microscopic analyses were performed. The posterior optic surfaces of the lenses also underwent scanning electron microscopy coupled with energy dispersive x-ray spectroscopy for analysis of the elemental composition of the deposits.

RESULTS

Gross and light microscopic analyses revealed well-demarcated areas of whitish deposits on the posterior optic surface of the lenses, as well as multiple pits caused by Neodymium:yttrium aluminum garnet laser treatments. The deposits formed an amorphous layer with a "crustlike" appearance, which was confirmed by scanning electron microscopy. X-ray spectroscopy analyses demonstrated the composition of the deposits to be similar to hydroxyapatite.

CONCLUSIONS

The material opacifying the lenses was probably derived from the asteroid bodies or from a similar process that results in this vitreous condition. We were unaware of this association between asteroid hyalosis and late postoperative dystrophic calcification of silicone lenses.

Posterior capsule opacification: a review of the aetiopathogenesis, experimental and clinical studies and factors for prevention

Posterior capsule opacification (PCO, secondary cataract, after cataract) is a nagging postsurgical complication following extracapsular cataract surgery (ECCE) and intraocular lens (IOL) implantation. PCO should be eliminated since it has deleterious sequelae and Neodynium: Yttrium Aluminium Garnet (Nd: YAG) laser treatment often is an unnecessary financial burden on the health care system. PCO following cataract surgery could be a major problem, since patient follow-up is difficult and the Nd:YAG laser is not always available. Advances in surgical techniques, IOL designs/biomaterials have been instrumental in bringing about a gradual and unnoticed decrease in the incidence of PCO. We strongly believe that the overall incidence of PCO and hence the incidence of Nd:YAG laser posterior capsulotomy is now rapidly decreasing - from 50% in the 1980s and early 1990s to less than 10% currently. Superior tools, surgical procedures, skills and appropriate IOL designs have all helped to significantly reduce this complication. In this article, we review the aetio pathogenesis, experimental and clinical studies and propose surgical and implant-related factors for PCO prevention. Careful application and utilisation of these factors by surgeons could lead to a significant reduction is secondary cataract, the second most common cause of visual loss worldwide.

Capsular bag opacification after experimental implantation of a new accommodating intraocular lens in rabbit eyes

PURPOSE

To evaluate the development of capsular bag opacification in rabbit eyes after implantation of an intraocular lens (IOL) designed to minimize contact between the anterior capsule and the IOL and ensure expansion of the capsular bag.

SETTING

David J. Apple, MD Laboratories for Ophthalmic Devices Research, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA.

METHODS

Ten New Zealand white rabbits had a study IOL (new accommodating silicone IOL [Synchrony, Visiogen, Inc.]) implanted in 1 eye and a control IOL (1-piece plate silicone IOL with large fixation holes) implanted in the other eye. Intraocular lens position, anterior capsule opacification (ACO), and posterior capsule opacification (PCO) were qualitatively assessed using slitlamp retroillumination photographs of the dilated eyes. Anterior capsule opacification and PCO were graded on a 0 to 4 scale after the eyes were enucleated (Miyake-Apple posterior and anterior views after excision of the cornea and iris). The eyes were also evaluated histopathologically.

RESULTS

The rate of ACO and PCO was significantly higher in the control group. Fibrosis and ACO were almost absent in the study group; the control group exhibited extensive capsulorhexis contraction, including capsulorhexis occlusion. Postoperative IOL dislocation into the anterior chamber and pupillary block syndrome were observed in some eyes in the study group.

CONCLUSIONS

The special design features associated with the study IOL appeared to help prevent PCO. Complications in the study group were probably caused by the increased posterior vitreous pressure in rabbit eyes compared to human eyes and the relatively large size of the study IOL relative to the anterior segment of rabbit eyes.

Removal times and techniques of a viscoadaptive ophthalmic viscosurgical device

PURPOSE

To analyze removal techniques for Healon5 (sodium hyaluronate 2.3%).

SETTING

Center for Research on Ocular Therapeutics and Biodevices, Charleston, South Carolina, USA, and Department of Ophthalmology, Ruprecht-Karls-University, Heidelberg, Germany.

METHODS

In a standardized laboratory setup, the Miyake-Apple posterior view video technique in human autopsy eyes was used to evaluate removal of an ophthalmic viscosurgical device (OVD) from capsular bags implanted with poly(methyl methacrylate), silicone, and acrylic intraocular lenses (IOLs). Healon5 was stained with fluorescein for better visualization. Open-sky preparation and an Alcon Legacy Series 20000 phaco machine with a flow rate of 25 mL/minute and a vacuum setting of +500 mm Hg (maximum irrigation/aspiration [I/A]) were used. With Technique 1, the I/A tip was placed on the center of the IOL and maximum aspiration was applied. With Technique 2 (modified rock 'n roll technique), the I/A tip was moved in quick circular movements on top of the IOL to break the OVD chains and facilitate aspiration.

RESULTS

With Technique 1, the mean removal time was 59.0 seconds +/- 23.1 (SD) and with Technique 2, 23.6 +/- 10.3 seconds (P =.004). The removal time of Healon5 correlated with the IOL material. With Technique 2, removal was fastest with silicone IOLs (13.5 +/- 2.1 seconds) followed by PMMA IOLs (17.5 +/- 2.1 seconds). With acrylic IOLs, remnants of the OVD trapped behind the IOL optic resulted in a longer removal time of 34.1 +/- 1.2 seconds.

CONCLUSIONS

Healon5 was completely removed from the capsular bag with the modified rock 'n roll technique. With acrylic IOLs, remnants can be trapped behind the optic and may be overlooked with an unstained OVD. Aspiration behind the optic is recommended with this IOL type.

Endothelial cell integrity after phacoemulsification with 2 different handpieces

PURPOSE

To investigate corneal endothelial cell loss in fresh phakic human autopsy cadaver eyes after phacoemulsification (PE) with a conventional handpiece or a new oscillatory handpiece.

SETTING

Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.

METHODS

Twenty fresh phakic human autopsy globes were randomized to PE with a conventional handpiece (n = 10) or an oscillatory handpiece (n = 10). The main parameters evaluated were age, nucleus density, amount of ophthalmic viscosurgical device (OVD) used, and mean PE time and ultrasound (US) power. After surgery, the corneas were excised and the endothelia were vitally stained with trypan blue and alizarin red. Light microscopy was used to assess the endothelial cell loss.

RESULTS

The mean age, density of the nucleus, OVD used, and US power were similar between the groups. The mean PE time was less with the NeoSoniX handpiece (0.71 minutes +/- 0.39 [SD]) than with the conventional handpiece (1.05 +/- 0.53 minutes). The mean number of dead endothelial cells was significantly lower in the oscillatory handpiece group (31.3 +/- 24.2 cells/mm(2)) than in the conventional handpiece group (60.4 +/- 46.8 cells/mm(2)) (P<.001, Mann-Whitney rank sum test).

CONCLUSIONS

Less corneal endothelial cell loss occurred after PE with an oscillatory handpiece than with a conventional handpiece. Further randomized clinical trials are recommended to validate this study.

Evaluation of preoperative and postoperative prophylactic regimens for prevention and treatment of diffuse lamellar keratitis

PURPOSE

To investigate preoperative and postoperative prophylactic treatment with different pharmacological agents before flap cutting and exposure to a diffuse lamellar keratitis (DLK) causative agent.

SETTING

Magill Research Center for Vision Correction, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.

METHODS

The study comprised 48 eyes of 24 Dutch-belted rabbits. Three days before a corneal flap was cut and the corneal interface was exposed to Pseudomonas aeruginosa lipopolysaccharide endotoxin, a DLK causative agent, the eyes were randomly assigned to treatment with a mast-cell stabilizer, a nonsteroidal antiinflammatory drug (NSAID), or a corticosteroid or left without treatment as controls. The treatment was maintained throughout the 1-week follow-up. Slitlamp examinations and photographs were performed at 1, 3, 5, and 7 days; DLK was graded by a masked observer from 0 (no DLK) to IV. Corneal interface scrapings were performed in selected eyes on day 7.

RESULTS

At the end of the follow-up, 36 eyes were available for evaluation. At 1 week, 100% of the control eyes and the eyes treated with the mast-cell stabilizer developed DLK; in the NSAID-treated and corticosteroid-treated eyes, the DLK rate was 86% and 70%, respectively. At 1 day, the severity of DLK was significantly lower in eyes treated with the mast-cell stabilizer (0.44) and at 7 days, it was significantly lower in corticosteroid-treated eyes (0.3) than in the control group (1.5 and 1.4, respectively) (P<.05, Wilcoxon test). Corneal interface scraping from an eye with grade III DLK showed numerous inflammatory cells.

CONCLUSIONS

Preoperative and postoperative treatment with corticosteroids significantly reduced the severity of DLK compared to the untreated control eyes in this animal model. Treatment with a mast-cell stabilizer and an NSAID had less effect on the postoperative course of DLK.

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.

Pharmacologic prevention of posterior capsule opacification: in vitro effects of preservative-free lidocaine 1% on lens epithelial cells

PURPOSE

To assess the in vitro effectiveness of preservative-free lidocaine 1% in removing lens epithelial cells (LECs) from the anterior capsule and to evaluate the effect of lidocaine on the LECs.

SETTING

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

METHODS

Eight rabbits (16 eyes) were used in the study. After the rabbits were killed, the eyes were enucleated and divided into 2 groups. In Group 1 (n = 8 eyes), LECs were exposed to preservative-free lidocaine 1% or balanced salt solution (BSS) for 1, 2, or 5 minutes. The anterior capsules were then stained with trypan blue and alizarin red. Photomicrographs of each capsule were taken and analyzed for LEC damage. In Group 2 (n = 8 eyes), hydrodissection was performed with 1 of the agents, followed by phacoemulsification and cortical cleanup. The LEC attachment to the anterior capsule was evaluated by histopathology.

RESULTS

Anterior capsule fragments irrigated with BSS showed no LEC nuclear staining; ie, no direct toxic effect. In those irrigated with preservative-free lidocaine 1%, the LECs showed mild toxicity; some cells showed blue nuclear staining. After hydrodissection with lidocaine, the capsules were almost free of LECs; after hydrodissection with BSS, the capsules showed a normal layer of LECs attached to the anterior capsule.

CONCLUSIONS

Preservative-free lidocaine 1% may help diminish the amount of live LECs by facilitating cortical cleanup, by loosening the desmosomal area of cell-cell adhesion with decreased cellular adherence, or by a direct toxic effect. The use of this agent may help prevent posterior capsule opacification.

Management of bipseudophakia with implantation of an iris claw lens

We discuss a case of bipseudophakia with secondary dislocation of a posterior chamber intraocular lens (IOL) into the anterior chamber that was managed by explantation of the anterior and posterior chamber IOLs and implantation of an iris claw IOL.

Cataract treatment in the beginning of the 21st century

PURPOSE

To describe the principles upon which present day cataract treatment success resides.

DESIGN

Literature review and collective experience of the authors.

RESULTS

Surgical removal remains the standard treatment for cataract now and in the foreseeable future. Ultrasound cataract removal with a foldable "in-the-bag" intraocular lens with a truncated edge treated for dysphotopsia best correlates with core treatment principles, as we now understand them. Improving refractive results is an important trend. The worldwide burden of this problem is immense.

CONCLUSIONS

While results for treatment of cataracts are excellent today, improvements in safety and refraction precision are needed. Other approaches are desperately needed to stem the worldwide tide of cataract related ocular dysfunction.

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.

Corneal flap complications in refractive surgery: Part 1: development of an experimental animal model

PURPOSE

To report the outcome, learning curve, and complication rates of an experimental animal model for corneal flaps in refractive surgery.

SETTING

Magill Research Center for Vision Correction, Storm Eye Institute, Charleston, South Carolina, USA.

METHODS

Corneal flaps with a nasal or a temporal hinge were created in 190 eyes of 95 Dutch Belted rabbits using the Automated Corneal Shaper microkeratome (Bausch & Lomb Surgical). Diffuse lamellar keratitis (DLK) was induced by inoculating the corneal interfaces with 1 of 7 substances. Postoperatively, the eyes were examined with a slitlamp. Special emphasis was placed on corneal flap complications and the relationship between slipped flaps and hinge position and/or inoculation agent.

RESULTS

A good corneal flap was achieved in 174 eyes (92%). The eyes with a nasal hinge had a lower incidence of slipped flaps (14%) than eyes with a temporal hinge (37%) (P =.02).

CONCLUSION

With the animal model described, corneal flaps were created in a precise and reproducible way in more than 90% of eyes. Nasal hinged flaps showed less postoperative displacements than temporal hinged flaps and are adequate for further study.

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.

Corneal flap complications in refractive surgery: Part 2: postoperative treatments of diffuse lamellar keratitis in an experimental animal model

PURPOSE

To induce diffuse lamellar keratitis (DLK) and investigate a prophylactic treatment with pharmacological agents.

SETTING

Magill Research Center for Vision Correction, Storm Eye Institute, Charleston, South Carolina, USA.

METHODS

In 100 eyes of 50 Dutch Belted rabbits, a nasal corneal flap was cut and the interface inoculated with Pseudomonas aeruginosa lipopolysaccharide endotoxin (n = 50) or Palmolive Ultra soap (n = 50). The eyes were randomly assigned to treatment with a mast-cell stabilizer, a nonsteroidal antiinflammatory drug (NSAID), a fluoroquinolone antibiotic agent, a corticosteroid, or left without treatment as a control. Slitlamp examinations and photographs were performed 1, 3, 5, and 7 days postoperatively, and DLK was graded by a masked observer from 0 (no DLK) to stage 4.

RESULTS

At the end of the study, 80 eyes were available for evaluation. Ninety-four percent of the untreated eyes developed DLK compared to 56% of eyes treated with NSAIDs and 63% of eyes treated with steroids (P<.05, Fisher exact test). The DLK rates with the mast-cell stabilizer and fluoroquinolone antibiotic agent were 86% and 76%, respectively. The DLK incidence in the latter 2 groups was not significantly different from that in the control eyes (P>.05, Fisher exact test).

CONCLUSIONS

Postoperative prophylactic treatment with NSAIDs and corticosteroids led to a statistically significantly lower incidence of postoperative DLK. The study demonstrated that corticosteroids and NSAIDs can be used to treat DLK after LASIK. While steroids are a generally accepted treatment for DLK, NSAIDS may offer an additional potent modality.

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.

Diffuse lamellar keratitis: evaluation of etiology, histopathologic findings, and clinical implications in an experimental animal model

PURPOSE

To induce diffuse lamellar keratitis (DLK) and investigate the potential causative agents in an animal model.

SETTING

Magill Research Center for Vision Correction, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.

METHODS

In 70 eyes of 35 Dutch Belted rabbits, a corneal flap was cut and the interface randomly exposed to 1 of 7 substances: Pseudomonas aeruginosa endotoxin, 1 of 2 Staphylococcus aureus exotoxins, meibomian gland secretion, povidone-iodine 10%, Palmolive Ultra soap, and Klenzyme soap. Slitlamp examinations were performed 1, 3, 5, and 7 days postoperatively. The DLK was staged from 1 to 4. On day 7, the rabbits were killed and the eyes enucleated and processed for histopathologic examination.

RESULTS

At the end of the study, 54 eyes (46 exposed, 8 control) were available for evaluation. The 8 eyes studied concurrently in the control group remained clear and did not show interface inflammation. Thirty-one of 46 eyes (67%) treated with the various test substances developed DLK. The highest DLK rates were found with the cleaning soap Palmolive Ultra (100%; P =.022) and P. aeruginosa lipopolysaccharide endotoxin (90%; P =.026).

CONCLUSIONS

Interface inflammation was consistently induced in the animal model. All 7 agents caused DLK in at least some eyes. The histopathologic evaluation showed the morphologic profile of the marked inflammatory cellular reaction that occurred in almost all the specimens.

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.

Randomized, clinical trial of multiquadrant hydrodissection in pediatric cataract surgery

PURPOSE

Evaluate efficacy of multiquadrant cortical-cleaving hydrodissection in pediatric cataract surgery.

DESIGN

Randomized multicenter clinical trial.

METHODS

Surgery performed at Iladevi Cataract & IOL Research Center (57 eyes, 42 patients) and Postgraduate Institute of Medical Education and Research (23 eyes, 17 patients). Study population comprised 59 consecutive patients (80 eyes) 12 years old and younger undergoing cataract aspiration. The intervention procedure involving envelope randomization was used to assign patients to multiquadrant cortical-cleaving hydrodissection (HY) (40 eyes), or no hydrodissection (HN) (40 eyes). The main outcome measures were as follows: (1) lens-substance removal time and volume of fluid used and (2) ease of lens substance removal. Presence or absence of residual fibers on the posterior capsule was recorded.

RESULTS

The mean +/- standard deviation lens substance removal time was significantly less in the HY group (156.1 +/- 86.8 seconds) than in HN group (210.7 +/- 73.8 seconds; P =.003). Fluid used for lens substance removal was significantly less in the HY (91.0 +/- 47.5 ml) than in the HN group (156.9 +/- 87.2 ml; P <.001). In the HY group, lens substance removal was ranked as easy in 36 eyes (90.0%), average in 2 eyes (5.0%), and difficult in 2 eyes (5.0%). In the HN group, removal was easy in 19 eyes (47.5%), average in 12 eyes (30.0%), difficult in 5 eyes (12.5%), and very difficult in 4 (10.0%) eyes (P =.0005). Residual cortical fibers on the posterior capsule were noted in 12.5% of the HY group and 22.5% of HN group, but the difference was not statistically significant (P =.2).

CONCLUSIONS

Multiquadrant cortical-cleaving hydrodissection decreases lens substance removal time, lessens fluid volume used for lens substance removal, and facilitates lens substance removal in pediatric cataract surgery.