Effect of heparin surface modification in reducing silicone oil adherence to various intraocular lenses

PURPOSE

To evaluate surface properties of various intraocular lenses (IOLs), including a newly fabricated heparin-surface-modified (HSM) silicone IOL, with special reference to their efficiency in reducing potential silicone oil adherence to the IOL optics.

SETTING

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

METHODS

Five groups of rigid and foldable IOLs were analyzed in an in vitro test for the percentage of silicone oil adherence: a single-piece foldable hydrophilic-acrylic IOL (n = 9); a single-piece rigid poly(methyl methacrylate) (PMMA) IOL with HSM coating of the lens optic (n = 9); a 3-piece foldable silicone optic IOL with HSM coating of the optic (n = 10); a single-piece standard rigid PMMA IOL (n = 7); and a standard 3-piece foldable silicone optic IOL (n = 9). After the IOLs were immersed in water and then in silicone oil, gross photographs taken. Image analysis was performed to evaluate the percentage of silicone oil coverage of the anterior and posterior surfaces of each IOL optic.

RESULTS

The mean silicone oil coverage of the hydrophilic-acrylic IOLs was 5.6% +/- 2.5% (SD); of the HSM PMMA IOLs, 6.2% +/- 4.3%; of the HSM silicone optic IOLs, 6.7% +/- 3.2%; and of the standard PMMA IOLs, 20.3% +/- 13.3%. The mean silicone oil coverage was greatest on the standard silicone optic IOLs, 98.2% +/- 3.1%.

CONCLUSIONS

Intraocular lenses with a hydrophilic optic have less tendency toward adherence to silicone oil than more hydrophobic designs. A foldable silicone IOL with heparin surface modification can significantly reduce potential silicone oil adherence, comparable to the level achievable with the rigid HSM PMMA designs. Two new foldable IOL styles, the HSM silicone IOL and IOLs in the general class of hydrophilic-acrylic, were highly efficacious in reducing silicone oil adherence. There is now a real choice of foldable lenses for patients with actual or potential vitreoretinal diseases.

No-anesthesia clear corneal phacoemulsification versus topical and topical plus intracameral anesthesia. Randomized clinical trial

PURPOSE

To compare the intraoperative pain scores during clear corneal phacoemulsification under no anesthesia, topical anesthesia, and topical plus intracameral anesthesia.

SETTING

Dr. Agarwal's Eye Hospital and Eye Research Center, Chennai, India.

METHODS

Seventy-five patients were randomized to have phacoemulsification under no anesthesia, topical anesthesia, or topical plus intracameral anesthesia. Uncooperative or illiterate patients and those with hard cataract, a shallow anterior chamber, or small pupils were excluded. A protocol was established for supplemental anesthesia in case of breakthrough pain during the surgery. Each patient was asked to grade the overall severity of intraoperative pain immediately after surgery on a 10-point visual analog scale. Also evaluated were the general discomfort during surgery, discomfort from the microscope lights, surgeon stress during surgery, and total surgical time. Comparison among the 3 groups was performed using an analysis of variance.

RESULTS

No supplemental anesthesia was required in any group. No significant difference was noted in the mean scores of the subjective sensation of pain with or without topical anesthesia (P =.610). The mean scores of patient discomfort from the microscope lights and surgical time were also statistically insignificant. Patient discomfort and surgeon stress during surgery were significantly greater in the no-anesthesia group than in the topical and topical plus intracameral groups (P =.0235 and P = 0.0206, respectively).

CONCLUSION

No-anesthesia clear corneal phacoemulsification was performed by a highly experienced, skilled surgeon without causing an unacceptable level of pain. However, this technique is not suitable for every cataract surgeon or patient.

[Millenniums update on posterior capsule opacification (PCO) scores, centration, biocompatibility and fixation of foldable intraocular lenses (IOL) - an analysis of 1,221 pseudophakic post mortem globes]

BACKGROUND

The ongoing and fast evolution of foldable IOL designs established the necessity to evaluate the different abilities of each lens style. The large IOL database (over 16,500 specimens) acquired in our laboratory, has permitted us to perform a clinico-pathological analysis on pseudophakic autopsy globes provided from sources worldwide, especially many Lions Eye banks in the United States.

MATERIAL AND METHODS

We analyzed 6 foldable IOL styles commonly implanted in the United States, using one type of rigid IOL design (1-piece design rigid PMMA optics) as a comparison group. Posterior capsule opacification (PCO) score, decentration, fixation, presence or absence of a Nd:YAG laser posterior capsulotomy and area and intensity of Soemmerring's ring formation was discerned by examination under an operating microscope using the Miyake-Apple posterior photographic technique.

RESULTS

The four lenses with the lowest rates ranging between 3.8 % and 21.7 % are modern designs, mostly implanted after 1992. The two lenses with the higher rates ranging between 23.1 % and 30.4 %, were all older designs, already prevalent prior to 1992. IOL fixation with both haptics in the capsular bag showed the best centration values and PCO scores. Our studies to date have shown in a preliminary fashion that the AcrySoftrade mark IOL displays the the lowest (best) biocompatibility score.

CONCLUSIONS

Entering the new millenium, with evolution of modern surgical techniques and IOL designs, the incidence of the two major complications of cataract surgery, decentration and PCO are now finally diminishing.

[Postoperative opacification of posterior chamber intraocular lenses - a review]

Postoperative opacification of intraocular lenses (IOLs) is a very unpleasant complication for the ophthalmic surgeon and the patient. We report on our experiences with opacification of different foldable IOL designs and rigid poly (methyl methacrylate) (PMMA) posterior chamber lenses.1. Snowflake degeneration of PMMA IOLs: This condition is an unanticipated and surprising late postoperative finding 8 to 15 years after implantation. In our opinion, this complication is probably not related to the PMMA biomaterial itself, but rather it appears to represent a manufacturing problem that has affected a selected, albeit large number of lenses manufactured in the 1980s-mid 1990s.2. Degeneration of UV absorber material and calcium deposits within the optic of hydrophilic IOLs: Two years postoperatively degenerations of UV absorber material and calcium deposits within the optic of single piece hydrophilic acrylic lenses SC60B-OUV manufactured by MDR (Medical developmental research Inc. Clearwater FL, USA) can occur. Although the precise mechanism is not fully known, it was assumed that these opacifications are due to premature aging of the UV blocking agent incorporated in the lens biomaterial and calcification.3. Calcification on the surface of the Bausch & Lomb Hydroviewtrade mark IOLs: Twelve to 15 months postoperatively granular surface calcifications in Hydroviewtrade mark IOLs occured. The mechanism is not fully understood. According to Bausch and Lomb studies, part of the components of the packaging contained silicone, which may have come off the packaging onto the lens optic, where it then appears to be a catalyst for calcium precipitation. The manufacturer has correlated a change in packaging with the appearance of the opacification. The manufacturer now believes that this problem has been solved. However, final verification will require a careful 1 - 2 years clinical study.4. Glistenings in the hydrophobic acrylic AcrySoftrade mark IOLs: The time frame of glistenings in the AcrySoftrade mark IOLs is highly variable. It has been suggested that the occurrence of glistenings may be related to variations in the temperature of the lens just prior to and or during insertion into the eye. Formation of vacuoles may occur within the submersed acrylic polymer when there is a transient increase and then decrease in temperature during the surgical procedure. "Glistenings" may then subsequently form by ingress of anterior chamber fluid. Contrast sensitivity can been decreased in some patients, but clinically significant decrease of visual acuity has been rare.

Dense opacification of the optical component of a hydrophilic acrylic intraocular lens: a clinicopathological analysis of 9 explanted lenses

PURPOSE

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

SETTING

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

METHODS

Nine hydrophilic IOLs (SC60B-OUV, MDR Inc.) were explanted from 9 patients with decreased visual acuity. Most patients became symptomatic approximately 24 months after uneventful phacoemulsification and IOL implantation. Opacification was noted and appeared clinically to be associated with a fine granularity within the substance of the IOL optic. The IOLs were forwarded to the center and examined by gross and light microscopy. Full-thickness cut sections of the optics were stained with 1% alizarin red and the von Kossa method (special stains for calcium). Some were submitted for scanning electron microscopy and energy dispersive x-ray spectroscopy.

RESULTS

Microscopic analyses revealed multiple fine, granular deposits of variable sizes within the lens optics, usually distributed in a line parallel to the anterior and posterior curvatures of the optic, with a clear zone just beneath the optic surface. The deposits stained positive with alizarin red and the von Kossa method. Energy dispersive x-ray spectroscopy of the internal substance of sectioned IOLs demonstrated the presence of calcium within the deposits.

CONCLUSION

This is the first clinicopathological report of optic opacification occurring with this hydrophilic acrylic IOL model. Studies of similar cases with this lens should be done to determine the incidence and possible mechanisms of the phenomenon.

Anterior capsule opacification: correlation of pathologic findings with clinical sequelae

OBJECTIVE

To evaluate the degree of anterior capsule opacification (ACO) in human eyes obtained postmortem containing various rigid and foldable posterior chamber intraocular lens (PC-IOL) designs and compare the findings with clinical sequelae of capsular shrinkage.

DESIGN

Comparative autopsy tissue study with clinicopathologic correlations.

MATERIALS

Three hundred formalin-fixed human eyes containing the following PC-IOL styles were analyzed: (1) one-piece polymethyl methacrylate (PMMA) optic-PMMA haptic (n = 50), one-piece silicone-plate IOL, with large (2) or small (3) fixation holes (n = 35), (4) three-piece PMMA optic-Prolene haptic (n = 50), (5) three-piece acrylic optic-PMMA haptic (n = 55), three-piece silicone optic with PMMA (6) or polyimide (7) haptics (n = 30), and (8) three-piece silicone optic-Prolene haptic (n = 80) lenses.

TESTING

The eyes were sectioned in the equatorial plane for gross examination of the capsular bag from a posterior view. The cornea and iris were then excised for evaluation from an anterior view.

MAIN OUTCOME MEASURES

ACO was scored in each eye from 0 to IV, according to the degree/area of capsule opacification. Capsulorrhexis size and IOL decentration were measured with calipers.

RESULTS

The overall differences among the IOL groups regarding the three parameters were significant (ACO score: P < 0.001; capsulorrhexis diameter: P = 0.036; IOL decentration: P = 0.012). Mean ACO scores were highest with the large- and small-hole one-piece silicone-plate lenses (2.543 +/- 0.950) and lowest with the three-piece acrylic optic-PMMA haptic lenses (0.600 +/- 0.710). Of 10 cases of capsulorrhexis phimosis observed in the study, 7 cases were associated with three-piece silicone optic-Prolene haptic lenses, which also presented the highest mean decentration (0.375 +/- 0.601 mm).

CONCLUSIONS

Our results confirm previous histopathologic observations that the rate of ACO is the lowest with acrylic lenses and higher with plate-haptic silicone IOLs. Nevertheless, clinical sequelae of capsular shrinkage are also very important with three-piece silicone optic-Prolene haptic designs. Thus, IOL material and design are significant factors in the development of ACO, but they ultimately also influence the clinical presentation of capsular shrinkage.

[Influence of surgery-related factors on the Nd:YAG laser capsulotomy rates of 3-piece silicone IOLs - analysis of 457 pseudophakic human globes obtained post mortem]

BACKGROUND

The purpose of this study was to analyze any possible surgical reasons which may have had caused posterior capsule opacification in 3-piece silicone IOLs that had required Nd:YAG laser treatment. Special attention was given to 1) quality of cortical clean up, 2) type of haptic fixation, and 3) continuous curvilinear capsulorhexis (CCC) size and shape.

MATERIALS AND METHODS

Human eyes obtained post-mortem implanted with 3-piece silicone optic - PMMA haptic (SI 40 NB) and 3-piece silicone optic - Prolene haptic (SI 30 NB) designs IOLs, accessioned between January 1993 and December 2000 were evaluated by gross examination from behind under an operating microscope using the Miyake-Apple posterior photographic technique. The area and intensity of Soemmerring's ring and type of fixation was studied in 457 eyes. The mean diameter of the CCC and relation of the CCC edge to the optic rim were analyzed in 221 eyes.

RESULTS

1) The amount of Soemmerring's ring formation was significantly larger in the group of IOLs requiring Nd:YAG capsulotomy in both the SI 40 NB and SI 30 NB design than in the IOLs without capsulotomies. 2) The percentage of not in-the-bag fixated IOLs in both the SI 40 NB and SI 30 NB design was larger in the "Nd:YAG groups", without being statistically significant. 3) The "Nd:YAG groups" showed a significant higher amount of non overlapping clock hours of the CCC edge in relation to the optic rim.

CONCLUSION

1) The data confirm the clinical assumption that the incidence of PCO is correlated with the cortical clean up. 2) Our findings also support the clinical assumption, that poor IOL fixation increases the risk of PCO. 3) This study also verifies the relation of the CCC to PCO, namely a relatively small CCC covering the entire optic rim is best to reduce the Nd:YAG laser rate.

Effect of in-the-bag intraocular lens fixation on the prevention of posterior capsule opacification

PURPOSE

To compare the incidence of posterior capsule opacification (PCO) after extracapsular cataract extraction (ECCE) and phacoemulsification and to evaluate the role of posterior chamber intraocular lens (PC IOL) haptic fixation and biomaterial/design in reducing the incidence.

SETTING

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

METHODS

This study comprised 278 eyes of 263 patients having ECCE and 318 eyes of 297 patients having phacoemulsification with PC IOL implantation. Posterior capsule opacification leading to a decrease in Snellen visual acuity of 2 or more lines was considered visually significant. The presence of PCO and IOL haptic fixation were evaluated postoperatively using slitlamp biomicroscopy. Haptic position was noted as in-the-bag (B-B), 1 haptic in the bag and 1 in the sulcus (bag-sulcus [B-S]), or both haptics out of the bag (sulcus-sulcus [S-S]). In addition, the rate of visually significant PCO was compared among 3 IOL biomaterials: poly(methyl methacrylate), silicone, and hydrophobic acrylic.

RESULTS

Visually significant PCO occurred in 42.45% of eyes having ECCE and 19.18% of eyes having phacoemulsification (P <.001, chi-square test) after a mean follow-up of 2.4 years +/- 0.7 (SD). In both groups, visually significant PCO was significantly less in eyes with B-B fixation than in those with B-S or S-S fixation (P <.001). The rate of visually significant PCO in all eyes in the phacoemulsification group with B-B fixation was low (11.90%) and was significantly lower in eyes with a hydrophobic acrylic IOL (2.22%; P <.05, chi-square test).

CONCLUSIONS

In-the-bag PC IOL fixation is required to consistently reduce the incidence of PCO. Thorough removal of lens substance, including hydrodissection-assisted cortical cleanup, and in-the-bag PC IOL fixation seem to be the most important factors in reducing PCO, regardless of surgical procedure or IOL type used. Intraocular lens biomaterial and design also help prevent PCO.

Eradication of posterior capsule opacification: documentation of a marked decrease in Nd:YAG laser posterior capsulotomy rates noted in an analysis of 5416 pseudophakic human eyes obtained postmortem

OBJECTIVE

(1) To report the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser posterior capsulotomy rate (%) of eight rigid and foldable intraocular lens (IOL) designs in a series of 5416 pseudophakic human eyes obtained postmortem, accessioned in our center between January 1988 and January 2000. (2) To identify factors that are instrumental in reducing the incidence of posterior capsule opacification, (PCO, secondary cataract) and hence the need for Nd:YAG laser posterior capsulotomy.

DESIGN

Comparative autopsy tissue analysis.

PARTICIPANTS

A total of 5416 globes with posterior chamber intraocular lens (PC-IOLs) obtained postmortem received from Lions Eye Banks between 1988 and 2000.

METHODS

Miyake-Apple posterior photographic technique. Special reference was given to the presence or absence of Nd:YAG laser posterior capsulotomy orifice on the posterior capsule of each eye.

MAIN OUTCOME MEASURES

The Nd:YAG laser posterior capsulotomy rate (%) as of January 2000 was documented. In addition, the Nd:YAG laser posterior capsulotomy rate for each lens was plotted on a monthly basis for the same period, creating a computerized trend or "timeline" for each IOL style.

RESULTS

Relatively high Nd:YAG laser posterior capsulotomy rates ranging from 20.3% to 33.4% were noted with four relatively older designs (high incidence of implantation between 1988 and the early 1990s). Four modern foldable IOLs manufactured from silicone and acrylic materials had significantly lower Nd:YAG laser posterior capsulotomy rates ranging from 0.9% (Alcon Acrysof) to 17.1%. The difference in Nd:YAG rates among the eight IOL designs was found to be significant (P < 0.0001, chi-square test). Comparing foldable versus rigid designs, the foldable IOLs were associated with a much lower Nd:YAG laser posterior capsulotomy rate (14.1% vs. 31.1%).

CONCLUSIONS

By use of the six factors regarding surgical technique and IOL choice described in this article, we strongly believe that the overall incidence of PCO and hence the incidence of Nd:YAG laser posterior capsulotomy is now rapidly decreasing from rates as high as 50% in the 1980s to early 1990s. Surgical tools and IOLs are now available to bring these rates down to single digits. Careful application and use of these tools by surgeons can genuinely lead in the direction of virtual eradication of secondary cataract, the second most common cause of visual loss worldwide.

Complications of cataract and refractive surgery: a clinicopathological documentation

PURPOSE

To present selected complications of keratorefractive and phakic intraocular lens (IOL) surgery and a series of IOLs that required explantation because of various postimplantation opacification of the IOL optic.

METHODS

Two specimens obtained after keratorefractive surgery, 2 phakic IOLs, and a total of 23 explanted IOLs from cases in which postimplantation opacification of the IOL optic had occurred were studied. These included 6 Bausch and Lomb (B&L) Hydroview H60 M designs, 9 Medical Developmental Research (MDR) SC60B-OUV designs, and 24 IOLs with rigid PMMA optics that had been implanted in the 1980s and early 1990s. Of the latter, 8 required late explantation because of decreased visual acuity. Analyses performed included gross and light microscopic evaluation, histochemical staining, electron microscopy, and energy-dispersive spectroscopy.

RESULTS

We provide examples of 3 postrefractive surgery complications: (1) fungal keratitis after LASIK, (2) post-LASIK corneal decompensation, and (3) cataract formation after implantation of phakic posterior chamber IOLs. Regarding the IOL optic opacities, classifications of 3 types are described: (1) a surface calcification of the B&L Hydroview IOL; (2) diffusion of calcium into the substance of the optic of the hydrophilic "acrylic" SC60B-OUV MDR foldable IOL design, sometimes leading to total opacification of the IOL optic and also its haptics; (3) a distinct pattern of intraoptical opacification with rigid PMMA designs that we term a snowflake degeneration. This term is based on the clinical and pathologic appearance of the individual lesions. Each snowflake lesion represents a focal breakdown of PMMA material as opposed to deposition of exogenous material.

CONCLUSIONS

Analysis of complications of refractive surgery represents a new field of ocular pathology. The clinicopathological reports presented here provide an overview of selected complications after refractive surgery. We also help define 3 newly recognized, clinically significant conditions based on postoperative IOL optic opacification. The calcification processes noted on the 2 modern foldable designs studied here (B&L and MDR lenses) need further review by the manufacturers in order to reassess production processes, especially in terms of polymer selection, manufacturing techniques, and other factors required to produce a safe and effective lens. Any lens not meeting today's high standards should not be marketed. The important fact in recognizing the snowflake complication of PMMA IOLs as described here is to alert surgeons about the nature of the lesion so that they will not alarm patients or require extensive and unnecessary testing in trying to determine its pathogenesis. There is no reason why successful explantation cannot be performed in cases where severe visual decrease or loss has occurred.

Postoperative deposition of calcium on the surfaces of a hydrogel intraocular lens

OBJECTIVE

To report clinical, pathological and histochemical features of 5 Hydroview intraocular lenses (IOLs) explanted from five patients who had visual disturbances caused by postoperative deposits on the lens surfaces.

DESIGN

Noncomparative small case series with clinicopathologic and histochemical correlations.

PARTICIPANTS

Five hydrophilic IOLs explanted from five different patients. All patients presented with decreased visual acuity and glare circa 12 months after uneventful phacoemulsification and IOL implantation, associated with a red-brown granularity on the optical surfaces of the IOLs.

METHODS

The lenses were explanted, fixed in buffered formaldehyde and examined by gross and light microscopy.

MAIN OUTCOME MEASURES

Staining of the IOLs with 1% alizarin red and with the von Kossa method (both stains for calcium). Two additional IOLs were also stained and included as controls.

RESULTS

The optical surfaces of all five IOLs were covered by a layer of irregular granular deposits, composed of multiple fine, translucent spherical-ovoid granules. The deposits stained positive for calcium in all cases. No deposit or positive staining was observed on the IOLs haptics. Staining of the control IOLs was also negative.

CONCLUSION

This is the first histopathological report of calcified deposits on the surfaces of this hydrogel IOL model. Further studies on other similar cases with this lens should be done to determine the incidence and possible mechanisms of this phenomenon.

Adhesion of fibronectin, vitronectin, laminin, and collagen type IV to intraocular lens materials in pseudophakic human autopsy eyes. Part 2: explanted intraocular lenses

PURPOSE

To evaluate fibronectin, vitronectin, laminin, and collagen type IV adhesion to poly(methyl methacrylate) (PMMA), silicone, hydrophobic soft acrylate, and hydrogel intraocular lenses (IOLs) in human pseudophakic autopsy eyes.

SETTING

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

METHODS

Thirty-two autopsy eyes containing PMMA, silicone, soft acrylate, or hydrogel IOLs were assessed. The IOLs were explanted from the capsular bag, and both sides of the IOLs were immunohistochemically stained for fibronectin, vitronectin, laminin, or collagen type IV. The number of cells on the IOL surfaces was counted. The capsular bag from 1 eye containing a soft acrylate IOL was examined for fibronectin and vitronectin.

RESULTS

Hydrophobic soft acrylate IOLs had significantly more fibronectin adhering to their surfaces than PMMA (P <.01) or silicone (P <.01) IOLs, as well as more vitronectin. Silicone IOLs had more collagen type IV adhesion than the other IOLs (P <.05-.06). Collective protein adhesion differed significantly between soft acrylate IOLs and PMMA and silicone IOLs, but not between PMMA and silicone IOLs.

CONCLUSIONS

The greater amount of protein on the hydrophobic soft acrylate (AcrySof(R)) IOLs seems to support an adhesive mechanism for their attachment to the capsular bag. Fibronectin and vitronectin have functional domains to bind them to lens epithelial cells and the collagenous capsule. This kind of attachment could be a true bioactive bond and may be 1 reason the PCO and neodymium:YAG capsulotomy rates are lower in eyes with a soft acrylate IOL.

Adhesion of fibronectin, vitronectin, laminin, and collagen type IV to intraocular lens materials in pseudophakic human autopsy eyes. Part 1: histological sections

PURPOSE

To evaluate fibronectin, vitronectin, laminin, and collagen type IV adhesion to poly(methyl methacrylate) (PMMA), silicone, hydrophobic soft acrylate, and hydrogel intraocular lenses (IOLs) in pseudophakic human autopsy eyes.

SETTING

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

METHODS

Thirty-eight autopsy eyes containing PMMA, silicone, hydrophobic acrylate, or hydrogel IOLs were assessed. Histological sections were prepared from each eye, and immunohistochemical analyses were performed for fibronectin, vitronectin, laminin, and collagen type IV. One hundred fifty-two specimens were analyzed.

RESULTS

A sandwich-like structure (anterior or posterior capsule/fibronectin/1 cell layer/fibronectin/IOL surface) was seen in 12 of 14 autopsy eyes with soft acrylate IOLs, 3 of 10 with a PMMA IOL (P =.0094), 1 of 10 with a silicone IOL (P =.0022), and 0 of 4 with a hydrogel IOL (P =. 0041). The thicker fibrocellular tissue on the inner surface of the anterior or posterior capsule that was in contact with silicone IOLs was lined with collagen type IV. Vitronectin and laminin were not found at the fibrocellular tissue-IOL interface in any specimen.

CONCLUSIONS

This study seems to confirm the sandwich theory of posterior capsule opacification in eyes with an IOL and suggests that fibronectin may be the major extracellular protein responsible for the attachment of hydrophobic soft acrylate (AcrySof(R)) IOLs to the capsular bag. This may represent a true bioactive bond between the IOL and lens epithelial cells or between the IOL and the capsular bag and may be one reason the PCO and neodymium:YAG capsulotomy rates are lower in eyes with a soft acrylate IOL.

Opacification of piggyback IOLs associated with an amorphous material attached to interlenticular surfaces

PURPOSE

To report the pathological and ultrastructural features and interval surgical management of an atypical case of opacification between piggyback intraocular lenses (IOLs).

SETTING

Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, and Nature Coast EyeCare Institute and Surgery Center, Perry, Florida, USA.

METHODS

Opacification between 2 acrylic piggyback lenses was observed 16 months after implantation, with decreased best corrected visual acuity and a hyperopic shift. Elschnig pearls were observed in the peripheral interface between the lenses, and the central interface was occupied by an amorphous material. The pearls were surgically aspirated, but attempts to remove the central material were unsuccessful. The lenses were explanted and sent to the laboratory. Staining with hematoxylin and eosin (H&E), examination under a light microscope, and scanning electron microscopic analysis were performed.

RESULTS

The surfaces of the anterior IOL were relatively clear. The amorphous material, mostly attached to the center of the anterior surface of the posterior IOL, was homogeneously stained with H&E. No cell nucleus was observed in this region. Scanning electron microscopy showed that the IOL edge presented a smooth, regular surface relatively free of deposits. The most central region was covered by an irregular layer of an amorphous compact material with some cracks, fissures, or both on its surface.

CONCLUSIONS

Although the exact composition of the material between the lenses could not be established, hypotheses were advanced to understand the pathological mechanism associated with this condition. This case is different from those in previous reports of opacification composed of cortex and cells between piggyback IOLs.

Macular translocation: histopathologic findings in swine eyes

PURPOSE

Macular translocation has been proposed as an alternative technique in the treatment of some cases of choroidal neovascularization. The purpose of the paper is to report the histopathologic findings in the retina of swine eyes undergone macular translocation.

METHODS

Ten eyes of ten Yucatan pigs underwent posterior pars plana vitrectomy and scleral imbrication to achieve macular translocation. Mattress sutures were preplaced at the equator of the eyes. After a pars plana vitrectomy, balanced saline solution was injected under the temporal retina to produce a retinal detachment. Scleral imbrication was achieved by tightening the mattress sutures. An air-fluid exchange was performed and the eye was filled with sulfur hexafluoride 18%. The eyes were enucleated 2, 4, 8 and 12 weeks after surgery and analyzed under light and electron microscopy.

RESULTS

Macular translocation was achieved in all cases. The major findings consist of a minimal decrease in the number of photoreceptors outer segments; also a change in the morphology was noted. This included some degree of loss of vertical alignment and an increase in the interphotoreceptor space. There was a recovery in the morphology of the photoreceptors over time.

CONCLUSIONS

Minimal changes in the photoreceptors and retinal pigment epithelium are observed when macular translocation is performed with recovery of these changes over time. Scleral imbrication is an effective technique to achieve translocation of the fovea.

Dye-enhanced cataract surgery. Part 3: posterior capsule staining to learn posterior continuous curvilinear capsulorhexis

PURPOSE

To evaluate the use of 2 dyes for staining the posterior capsule to enhance visualization during posterior continuous curvilinear capsulorhexis (PCCC).

SETTING

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

METHODS

Indocyanine green 0.5% (ICG) and trypan blue 0.1% were used to stain the posterior capsule for performing PCCC in 8 human eyes obtained postmortem. The eyes were prepared according to the posterior video technique of Miyake-Apple. After CCC and hydrodissection/delineation were performed, the nucleus was carefully delivered by hydroexpression. Cortical cleanup was completed by irrigation/aspiration. The posterior capsule was stained by instilling 1 microdrop of ICG (4 eyes) or trypan blue (4 eyes) in the capsular bag. A PCCC was then performed by 2 independent surgeons (4 eyes/surgeon) not familiar with this technique. Each surgeon also performed PCCC in 2 eyes without the use of dye.

RESULTS

Both dyes facilitated the performance of PCCC after staining the otherwise transparent posterior capsule. It was easier to differentiate the stained posterior capsule flap from the underlying transparent anterior hyaloid phase of the vitreous. In addition, optic capture of an intraocular lens, with or without anterior vitrectomy, was easily accomplished because of the enhanced visualization by posterior capsule staining.

CONCLUSIONS

Posterior capsule staining can be successfully used to learn and perform the PCCC procedure, combined with optic capture, anterior vitrectomy, or both.