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.

The "demise" of diagnostic and research ocular pathology: temporary or forever?

PURPOSE

Several authorities have documented a significant decrease in support for modern eye pathology/pathology research laboratories. Indeed, many laboratories have closed or suffered marked cutbacks. The purpose of this report is to ask why this is so and to seek a possible means for reversing this trend.

METHODS

Observations from the senior author's experience and a case from author's facility are analyzed.

RESULTS

There are several reasons for ocular pathologists' difficulties, such as financial problems, lack of vision, personality conflicts, and problems with the departmental administration. Until recently, most research and development in several subspecialty fields of ophthalmology, including biodevices research, has been done primarily by engineers and in-house workers in industry. This precludes proper independent, nonbiased control and guidance from academia. Most ocular pathologists have not participated in this relatively new and wide-open field.

CONCLUSIONS

We suggest a new realm of activity for today's newly trained ocular pathologists. Based on personal experience of two decades of fruitful collaboration with industry, we believe that ocular pathologists are uniquely trained to apply their expertise to various new fields of research that most pathologists today have not utilized. An important example is research on clinicopathological aspects of implantable biodevices. In addition, support and oversight should be provided by the major ophthalmic societies, such as the American Academy of Ophthalmology, in order to retain (even regain) control over this field. This is mandatory in order to control the safety and efficacy of new drugs and devices being introduced almost daily. Only then can clear differentiation between profit and patient welfare be achieved as potentially dangerous devices and techniques are let loose on the market. The field of "routine, descriptive" eye pathology is severely wounded and will return only in an attenuated fashion. In general, full-time support for ocular pathologists will not be possible unless they seek extra support from the private sector, engage in a concurrent clinical practice, or are supported by an endowed chair (a wonderful alternative).

Epithelial downgrowth after clear cornea phacoemulsification: report of two cases and review of the literature

OBJECTIVE

To report two cases of diffuse epithelial downgrowth after clear cornea phacoemulsification and to review the different treatment options for this ominous disease.

DESIGN

Two interventional case reports.

METHODS

Retrospective review of two eyes from two different patients in whom epithelial downgrowth developed 7 and 3 months after uneventful clear cornea phacoemulsification. In the first case, the epithelial invasion seemed to be growing from the temporal incision site onto the corneal endothelium toward the visual axis. Cryotherapy was applied to the affected cornea, with control of the growing membrane. A penetrating keratoplasty was performed to restore visual function. In the second patient, the membrane was attached to the iris and posterior cornea and was confirmed by diagnostic argon laser photocoagulation. This case was surgically treated with en bloc excision and a corneoscleral graft.

MAIN OUTCOME MEASURES

Visual acuity at the final follow-up visit.

RESULTS

Surgical treatment of the epithelial downgrowth was different for both patients. In the postoperative period, a best-corrected visual acuity of 20/60 and 20/30 was achieved in each case. No regrowth of the membrane was observed.

CONCLUSIONS

Treatment of epithelial downgrowth is controversial. We present two cases of epithelialization of the anterior chamber with either clinical or histologic confirmation after clear cornea sutureless phacoemulsification. Surgical treatment should be attempted promptly to obtain a good visual prognosis.

[Diffuse lamellar keratitis: prophylactic treatment with ketorolac tromethamine 0.5% in an animal model]

PURPOSE

The objective of this study is to evaluate the use of a topical non-steroidal anti-inflammatory drug in the treatment of induced diffuse lamellar keratitis (DLK) in an animal model.

MATERIALS AND METHODS

A corneal flap was created in 40 eyes of 20 Dutch-belted rabbits using the ASC microkeratome. The interface was inoculated with either Pseudomonas Aeruginosa Lipopolysaccharide (LPS) endotoxin or Ultra Palmolive liquid dish washer. The rabbits were divided in two groups: Group I (n=20) treated with ketorolac tromethamine ophthalmic solution 0.5% 4 times a day and the group II (n=20) used as control. The rabbits were examined at the slit lamp at day 1, 3, 5 and 7 postoperatively. DLK was graded from I-IV.

RESULTS

At the end of the study 31 eyes were available for evaluation. 28 eyes (90%) developed DLK: 86% of the treated group and 94% of the control group during the follow-up. The treated group showed a lower rate of DLK as well as a lower severity. However, no statistically significant difference was found when comparing both groups (P>0.05).

CONCLUSION

Pseudomonas aeruginosa LPS endotoxin and Palmolive Ultra can induce DLK in rabbit eyes. The postoperative prophylactic treatment with a topical non-steroidal anti-inflammatory drug showed a tendency towards a lower DLK rate as well as the severity of the disease.

[Diffuse lamellar keratitis. Postoperative prophylactic treatment with corticosteroids in an experimental animal study]

PURPOSE

The aim of this experimental ani-mal study was to induce diffuse lamellar keratitis (DLK), and investigate a prophylactic treatment with corticosteroids.

MATERIALS AND METHODS

A corneal flap was cut in 40 eyes from 20 Dutch-belted rabbits and the interface inoculated with either Pseudomonas aeruginosa lipopolysaccharide (LPS) endotoxin ( n=21) or Palmolive Ultra soap ( n=19). Half of the eyes were treated with topical corticosteroids and the other half remained untreated. Slitlamp examinations were performed 1, 3, 5 and 7 days postoperatively and DLK was graded from I-IV.

RESULTS

At the end of the study 33 eyes were available for evaluation and 94% of the non-treated eyes developed DLK. Out of those eyes treated with steroids 19% developed DLK during the 1 week follow-up period. This was statistically significantly lower ( P=0.018) when compared to the untreated group.

CONCLUSION

Pseudomonas aeruginosa LPS endotoxin as well as Palmolive((R)) Ultra caused a very high rate of DLK in rabbit eyes. The postoperative prophylactic treatment with corticosteroids showed a statistically significant lower DLK rate in this rabbit eye model.

[Miyake-Apple video analysis of movement patterns of an accommodative intraocular lens implant]

BACKGROUND

The potentially accommodative intraocular lens (IOL) is a new development in IOL design

METHODS

We evaluated the new Humanoptics 1CU accommodative IOL in a laboratory study with human post mortem autopsy eyes. Using the Miyake-Apple posterior view video technique, the movement pattern of the IOL was tested and observed from the posterior perspective. RESULTS. A circular bend at the level of the ciliary body applied slight circular force onto the sclera allowing the relaxation of the zonules. The shift of focus was demonstrated by using a reading target. In addition, viscoelastic was injected into the vitreous resulting in the same anterior movement of the IOL optic.

CONCLUSIONS

The 1CU Humanoptics accommodative IOL showed potential accommodative behaviour in the laboratory. The accommodative (respectively pseudoaccommodative) effect was based on the anterior shift principle with anterior movement of the IOL-optic in the state of relaxing zonules. Whether this reflects the clinical situation, especially to this extent, must be further evaluated.

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.

Endothelial decompensation after laser in situ keratomileusis

We report the results of laser in situ keratomileusis (LASIK) in a 58-year-old woman with a history of corneal guttata in the right eye and mild Fuchs' dystrophy in the left eye. Preoperative pachymetry was 586 microm and 656 microm, respectively. The surgical treatment was +1.50 diopters (D) in the right eye and +3.25 D in the left eye. Surgery was performed using a VISX S2 Star laser and a Hansatome microkeratome with a 9.5 mm ring. Postoperatively, edema in the right eye resolved and pachymetry returned to 585 microm, but the left cornea decompensated despite maximum medical therapy and had a final pachymetry of 779 microm. The patient was referred to our cornea service for penetrating keratoplasty, which was performed 14 months after the LASIK treatment.

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.

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.

Snowflake degeneration of polymethyl methacrylate posterior chamber intraocular lens optic material: a newly described clinical condition caused by unexpected late opacification of polymethyl methacrylate

OBJECTIVE

To report 25 cases of gradual, but sometimes progressive, late-postoperative degeneration of polymethyl methacrylate (PMMA) optics of posterior chamber (PC) intraocular lens (IOL) implants, often resulting in a clinically significant visual decrease long after the implantation, sometimes to a severity that required IOL explantation/exchange.

DESIGN

Analysis of explanted PC IOLs, clinical histories, and photographs.

PARTICIPANTS

We analyzed 25 case histories/photographs and/or explants from 18 patients implanted in the 1980s to mid-1990s with three-piece PC IOLs with PMMA optics and with polypropylene or PMMA haptics. The IOL optic from each case had characteristic snowflake or crystalline opacifications. This condition occurred with more than one manufacturer and in some cases was restricted to certain lot numbers.

METHODS

The explanted IOLs (n = 10) were studied by gross inspection and by light and scanning electron microscopy, as well as confocal and energy dispersive spectroscopy.

MAIN OUTCOME MEASURES

The snowflake lesions were noted within the IOL optics. The nature of these lesions was investigated.

RESULTS

Assimilation of clinical information with pathologic and morphologic profiles of all cases suggested that the snowflake opacification was a small spherical lesion surrounded by an outer pseudocapsule composed of compressed, degenerated PMMA, with a central core containing convoluted fragments of PMMA. The lesions were classified into four clinical and pathologic grades according to their density and severity.

CONCLUSIONS

This is the first clinicopathologic correlative report on this complication. We postulate that manufacturing variations in some IOL models fabricated in the 1980s and early 1990s are responsible. The snowflake lesions seem to represent a destruction of the PMMA material. The cluster of lesions in implanted lenses manufactured by Surgidev was less progressive than some other models, including lenses made by IOPTEX Research Corporation. This identification of a condition previously unreported is important to alert clinicians regarding these perplexing lesions that may otherwise be considered idiopathic, with no obvious clinical hint as to their origin. The prevalence noted thus far is still too low to in any way suggest that this condition would occur in 100% of PMMA IOLs from these manufacturers. However, these late-occurring lesions, present in lens models that were implanted in hundreds of thousands of patients in the last decade or so, could have constituted a true epidemic, except that many of the patients are now deceased.

Evaluation of neodymium:yttrium-aluminum-garnet capsulotomies in eyes implanted with AcrySof intraocular lenses

PURPOSE

As of December 31, 2000, the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser posterior capsulotomy rate for the Alcon AcrySof intraocular lens (IOL) as measured in our database was 3.3%. This was the lowest of any IOL model used in the United States. Only 12 of 361 cases required treatment. We analyzed possible surgical reasons that may have been responsible for the posterior capsule opacification (PCO) in this small group. Special attention was given to the three surgical factors that we had previously identified as being important for PCO reduction: (1) quality of cortical clean up, (2) type of haptic fixation, and (3) continuous curvilinear capsulorhexis (CCC) size and shape.

DESIGN

Comparative autopsy tissue analysis.

PARTICIPANTS

Three hundred sixty-one human eyes obtained postmortem with Alcon AcrySof IOLs, accessioned between January 1995 and December 2000 from Lions Eye Banks.

METHODS

The eyes were evaluated by the Miyake-Apple posterior photographic technique.

MAIN OUTCOME MEASURES

The area and intensity of Soemmering's ring and type of fixation were studied in 361 eyes. The size and shape of the CCC and relation of the CCC edge to the IOL's optic rim were analyzed in 168 eyes.

RESULTS

The amount of Soemmering's ring formation was significantly larger in the group of IOLs requiring Nd:YAG capsulotomy (Nd:YAG group). The not in-the-bag fixated IOLs required more Nd:YAG capsulotomies. Although the trend was clear, the number of specimens was not large enough to acquire statistical significance. The Nd:YAG group showed a highly significant difference compared with the No Nd:YAG group with regard to the amount of clock hours of the CCC edge on the optic rim's surface (P < 0.001). Mean CCC diameters were significantly larger in the Nd:YAG group (P < 0.05).

CONCLUSIONS

The amount of Soemmering's ring correlates with the quality of cortical clean up. Cells within the Soemmering's ring are the direct precursors of PCO. This study confirms our previous laboratory studies and the clinical assumption that the incidence of PCO and thus the need for Nd:YAG capsulotomy is correlated with the cortical clean up. A second clinical assumption, that poor IOL fixation increases the risk of PCO, is also strongly suggested in this study. This study also verifies the relation of the CCC to PCO and the Nd:YAG laser, namely that a relatively small CCC without tears is best to prevent this complication. Use of a high-quality IOL combined with diligent attention to these three surgical factors should lower further the incidence of PCO.

Interface fungal infection after laser in situ keratomileusis presenting as diffuse lamellar keratitis. A clinicopathological report

PURPOSE

To report clinicopathological analyses of 3 cases of interface fungal infection following laser in situ keratomileusis (LASIK) and diffuse lamellar keratitis (DLK).

SETTING

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

METHODS

Clinicopathological analysis of 5 eyes of 3 patients who developed culture-proven interface fungal infection after LASIK was performed. Detailed pathological analysis of the amputated flap from 1 case included light, scanning, and transmission electron microscopy.

RESULTS

Culture and pathological analysis revealed Candida albicans in all 3 cases. Common links among the cases were early onset of DLK following intensive corticosteroid and antibiotic treatment and later onset of interface fungal infection. All cases resolved, and good visual acuity was restored after medical treatment with antifungal agents.

CONCLUSIONS

Interface fungal infection after LASIK can be sight-threatening. Early lifting of the flap, fungal culture, and aggressive antifungal treatment are required to treat this complication and avoid deleterious sequelae.

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.

Effect of haptic angulation on posterior capsule opacification in modern foldable lenses with a square, truncated optic edge

PURPOSE

To analyze the effect of different haptic angulations on posterior capsule opacification (PCO) in a modern foldable intraocular lens (IOL) with a square-edged optic designed to reduce the incidence of PCO.

SETTING

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

METHODS

Ten Dutch Belted, serum Pasteurella-free pigmented rabbits of the same age and sex had bilateral phacoemulsification with endocapsular IOL implantation. The eyes were implanted with Centerflex IOLs (Rayner) with haptic angulations of 0 degree (n = 8), 5 degrees (n = 4), 10 degrees (n = 4), or 15 degrees (n = 4).

RESULTS

There was no statistical difference in central PCO, peripheral PCO, and measured IOL decentration among the angulation groups.

CONCLUSION

With the Centerflex IOL, haptic angulation did not seem to be a significant factor influencing PCO. It appears that the barrier effect of the IOL's truncated, square-edged optic overrides the angulation factor in preventing PCO.

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.

Aqueous infiltration into an implantable miniaturized telescope

The implantable miniaturized telescope (IMT) is the first intraocular magnifying system proposed for optical correction in patients with age-related macular degeneration (ARMD). The optical component is embedded in a carrying device designed as an intraocular lens that is implanted after cataract surgery. In this study, we report findings on an IMT that was explanted because of aqueous infiltration into its optic and describe the configuration of this device and the surgical technique required for its implantation. The patient, a 75-year-old male with bilateral cataract and nonexudative ARMD, underwent phacoemulsification with implantation of an IMT in the right eye. The rigid device, weighing 46.1 mg in aqueous, has an overall diameter of 13.5 mm and requires implantation through a large limbal incision. It is fixated at the 6 to 12 o'clock meridian. Follow-up examination revealed the presence of numerous droplets inside the IMT optic. The device was explanted and sent to our center for evaluation. A large fissure was found on the carrying device. However, it was unlikely the site for aqueous infiltration. Microdefects at the level of the sealing of the optical cylinder appeared to provide the opening for the inflow of aqueous that formed droplets. Based on the findings of this report the manufacturer has modified the sealing technique to avoid this complication. Current clinical trials are now ongoing to assess the efficacy of this device in providing visual rehabilitation for ARMD patients.

Rates and causes of intraoperative removal of foldable and rigid intraocular lenses: clinicopathological analysis of 100 cases

PURPOSE

To analyze the rates of and reasons for intraoperative explantation of foldable and rigid intraocular lenses (IOLs) to determine the complication profile of each IOL design.

SETTING

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

METHODS

The study comprised data analysis of foldable (n = 85) and rigid (n = 15) IOL specimens that were explanted immediately after primary implantation.

RESULTS

Eighty-five foldable intraoperative explants were accessioned. These comprised 14.5% of the 586 foldable IOL explants received between January 1988 and September 2000. There were 15 rigid poly(methyl methacrylate) (PMMA) intraoperative explants out of 2077 rigid explant specimens (0.7%). Fifty-one (60%) of the foldable IOLs requiring intraoperative explantation were the 1-piece silicone plate-haptic large-hole design, and 29 (34.1%) were the 3-piece silicone polyimide-haptic design. The most frequent reason for explantation of both designs was optic damage, 37.3% in the large-hole design and 55.2% in the polyimide design. Optic damage did not occur in rigid PMMA IOLs.

CONCLUSION

Some foldable IOL designs have a higher risk of damage during surgical insertion than rigid designs. Two modern foldable IOLs, the silicone plate-haptic large-hole and the silicone polyimide-haptic, appear to be more prone to damage during folding, loading, and implantation than other IOLs.

Loop memory of haptic materials in posterior chamber intraocular lenses

PURPOSE

To compare the shape recovery ratios after compression of haptic materials used in the manufacture of intraocular lenses (IOLs).

SETTING

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

METHODS

The loop memory of 40 silicone-optic posterior chamber IOLs was studied. All the IOLs had modified-C haptics made of poly(methyl methacrylate) (PMMA; n = 10), polyimide (n = 10), polyvinylidene fluoride (PVDF; n = 10), and polypropylene (PP; n = 10). After the overall diameter of each lens was measured (day 0), the lenses were inserted into plastic wells (9.5 mm in diameter) and immersed in water (37 degrees C) for 1 month. They were then placed on an open plate and allowed to reexpand for 2 months. Overall diameter measurements were performed within 5 minutes of the IOLs' removal from the wells and at subsequent time points (days 14, 28, 30, 60, 74, 88, and 95).

RESULTS

The loop memory of each lens was expressed as the difference between the initial overall diameter measurement (pretest) and the measurement at each time point; the lower the value, the higher the memory. The overall difference among the 4 groups was statistically significant at each time point (P < or = .001). From days 30 to 95, silicone-PMMA, silicone-elastimide, and silicone-PVDF IOLs had similar loop memory mean values, which were significantly lower than the mean value of silicone-PP IOLs (P <.05). The latter design tended to be deformed after removal from the wells, with increased optic-haptic angulation.

CONCLUSION

Studying the loop memory of haptic materials (PMMA, polyimide, PVDF, and PP) used in the manufacture of posterior chamber IOLs can help surgeons choose an appropriate IOL for each patient.