Natural history of cellular deposits on the anterior intraocular lens surface

Reversible deposition of inflammatory cells on the surface of an intraocular lens in a patient with uveitis: Case report and literature review

INTRODUCTION

The deposition of inflammatory cells on an intraocular lens (IOL) is a rare but potentially serious complication. We report a patient who presented with reversible severe deposition of inflammatory cells on the anterior surface of a hydrophobic IOL.

CASE DESCRIPTION

A 68-year-old woman with remissive uveitis presented with blurred vision in her right eye that persisted for 1 month. She had undergone cataract surgery and hydrophobic IOL (ZA9003, Johnson & Johnson Surgical Vision) implantation 3 months before presentation. Deposition of inflammatory cells was diagnosed by ocular examination. The IOL became transparent after 6 months of treatment with combined antibiotic/steroid eyedrops (tobramycin/dexamethasone eyedrops) and atropine. However, the cellular deposition recurred after either discontinuing the tobramycin/dexamethasone eyedrops or switching to steroid-only eyedrops (fluorometholone). Therefore, she was prescribed continuous tobramycin/dexamethasone eyedrops, twice-daily, and her IOL remained transparent at the time of submission of this article.

CONCLUSIONS

We have reported a case of reversible severe deposition of inflammatory cells on the anterior surface of a hydrophobic IOL in a patient with uveitis that was managed by continuous administration of combined antibiotic/steroid eyedrops. The morphology of the inflammatory cells deposits and the treatment differed from those of previously reported cases.

Evaluating the Biostability of Yellow and Clear Intraocular Lenses with a System Simulating Natural Intraocular Environment

PURPOSE

Blue light-filtering intraocular lenses (IOLs) are thought to protect the retina from blue light damage after cataract surgery, and the implantation of yellow-tinted IOLs has been commonly used in cataract surgery. To our knowledge, this is the first investigation measuring the long-term biostability of yellow-tinted IOLs using an in vitro system simulating natural intraocular environment.

METHODS

Six hydrophobic acrylic IOLs, three clear IOLs, and three yellow-tinted IOLs were included in the study. Each yellow-tinted IOL was a matching counterpart of a clear IOL, with the only difference being the lens color. The IOLs were kept in conditions replicating the intraocular environment using a perfusion culture system for 7 months. Resolution, light transmittance rate, and the modulation transfer function (MTF) were measured before and after culturing. Surface roughness of the anterior and posterior surfaces was also measured.

RESULTS

After culturing for 7 months, there were no changes in the resolution, the light transmittance rate, and MTF. The surface roughness of the anterior and posterior surfaces increased after culturing; however, this increase was clinically insignificant. There were no differences in surface roughness between the clear and yellow-tinted IOLs, either before or after culturing.

CONCLUSIONS

A novel in vitro system replicating intraocular environment was used to investigate the biostability of yellow-tinted IOLs. The surface roughness showed no clinically significant increase after culturing for 7 months.

TRANSLATIONAL RELEVANCE

This system is useful for evaluating the biostability of IOLs.

Pigment deposits on hydrophilic intraocular lenses after phacoemulsification cataract surgery

A heterogeneous group of conditions can cause changes to the intraocular lens (IOL) during or after implantation in uneventful cataract surgery. We describe a series of 5 patients presenting distinctive deposits on the surface of hydrophilic intraocular lenses, implanted during routine cataract surgery, with a follow-up of 1 to 24 months. Disposable forceps were found to be the source of the pigmented marks when used to hold the lens during the injector loading process. At the slit-lamp examination, the pigments were located in the centre of the lens optic, easily detectable. Although involving the visual axis, none of the patients were visually affected. To our knowledge, this is the first time such unusual occurrence has been described. The reported case-series shows the importance of in-house follow-up after cataract surgery.

Chemoattraction of inflammatory cells by various intraocular lens materials

PURPOSE

To compare the chemotactic activity induced by polymethyl methacrylate (PMMA), acrylic, and silicone intraocular lens (IOL) materials, regardless of the surgical and host factors.

METHODS

The chemotactic effect of five different IOLs was studied using a modified multi-well Boyden chamber. Two different non-coated PMMA IOLs, a heparin-coated PMMA IOL, an acrylic IOL, and a silicone IOL were assessed. Each mean migration distance of the IOLs was compared with the others using Student's t test.

RESULTS

All IOLs induced some amount of leukocyte chemotaxis. There was no statistically significant difference between the chemotactic activity of PMMA IOLs. However, chemotactic activity was significantly higher in acrylic (p<0.05) and silicone (p<0.05) IOLs compared to one of the PMMA lenses.

CONCLUSIONS

This limited study has proven that chemotaxis assay is a useful tool to assess the biocompatibility of IOLs. The IOL material itself might attract inflammatory cells to its surface in the absence of surgical and host factors. As PMMA IOLs do not cause an increase in inflammatory reaction, they may be considered safe to use. Further improvement in chemical composition and surface characteristics of IOLs should reduce the inflammatory reaction and increase the biocompatibility and safety of IOLs.

Tissue reaction to hydrophilic intraocular lenses

The implant of intraocular lenses (IOLs) following cataract surgery induces a foreign body reaction to the IOL and a lens epithelial cell reaction. The host response to the IOL is mainly influenced by biomaterial properties. With the increasing use of phacoemulsification and small incision cataract surgery, there is growing interest in the use of foldable IOLs made of different materials. Hydrophilic acrylic IOLs include a wide group of foldable biomaterials different in terms of water content. These lenses have been reported to show a good biocompatibility after implantation. Nevertheless, tissue reaction to the implant of hydrophilic lenses is variable and not directly related to the hydrophilicity of their surface. A different adsorption of proteins on the IOL optic surface might be responsible for the different cellular reaction and lens epithelial cell response. Other properties besides hydrophilicity should be taken into account to classify IOL biomaterials.

Biological compatibility of polymethyl methacrylate, hydrophilic acrylic and hydrophobic acrylic intraocular lenses

PURPOSE

Extensive clinical investigations of the biocompatibility of different intraocular lenses (IOLs) have been made in an effort to optimize the outcome of modern cataract surgery. The aim of this study was to add animal eye experimental implantation data regarding cellular reaction on the anterior surface of IOLs.

METHODS

Thirteen adult albino rabbits had phacoemulsification/aspiration of the crystalline lens followed by implantation of a posterior chamber IOL in each eye. Three types of IOLs were studied: Hydroview (Bausch and Lomb; n = 7), Acrysof (Alcon, USA; n = 7), and polymethyl methacrylate (PMMA; HOYA, Japan; n = 7). The animals were killed by intravenous pentobarbital 1, 4, or 8 weeks later. The IOLs were explanted and stained with hematoxylin and eosin, and observed under a light microscope. The shape of mouse ascites-induced macrophages on the anterior surface of the three different IOL types (Hydroview, PMMA, and Acrysof) was studied after 24 h of oven culture.

RESULTS

Hydrophilic acrylic IOLs showed the highest affinity for lens epithelial cell (LEC) outgrowth, and the lowest and slowest maturation rate reaction of macrophages. PMMA IOLs showed the lowest affinity for LEC outgrowth, and the highest reaction of macrophages. Hydrophobic acrylic IOLs showed intermediate results both regarding LECs and macrophages.

CONCLUSIONS

Results suggest that IOL biomaterial properties are the key factor that influences the quantity of monocytes/macrophages as well as the process of their maturation/senescence. LEC outgrowth is influenced both by the biomaterial of IOLs and by the monocyte/macrophage reaction.

A 1-year study on carbon, titanium surface-modified intraocular lens in rabbit eyes

PURPOSE

To evaluate biocompatibility of Carbon (C) and Titanum (T) surface modified Polymethyl-methacrylate (PMMA) Intraocular Lens (IOLs) in pseudophakic rabbit model.

METHODS

Extracapsule Cataract Extraction (ECCE) and IOLs implantation were performed in Japanese albino rabbit eyes. The white cell concentration from the aqueous humor in the eyes was counted within 3 months post operation. The inflammatory cells in the eyes were noted and graded by slit lamp using a semiquantitive scale up to 1-year post operation. The rabbit eyes were inspected under light microscopy, where pathology of the eyes was caracterized.

RESULTS

The white cell concentration in the aqueous humor was significantly attenuated in C and T IOL-implanted eyes compared with PMMA IOL-implanted eyes 1 week post operation. The exudate levels in the anterior ocular chamber and the posterior synechias were significant lower in T IOL-implanted eyes than in PMMA IOL-implanted eyes 1 week and 2 weeks after surgery. The exudate levels in the anterior chambers and the posterior synechias were not significantly different in C IOL-implanted versus PMMA IOL-implanted eyes.

CONCLUSIONS

This in vivo study provides evidence of effectiveness of Carbon and Titanium IOLs in improving the biocompatibility of PMMA IOLs.

Cell response to AcrySof intraocular lenses in an Indian population

PURPOSE

To evaluate the quantitative cytological response to AcrySof (Alcon) intraocular lenses (IOLs) in an Indian population by studying the incidence, fate, progression, and severity of cell deposits after uneventful phacoemulsification.

SETTING

Iladevi Cataract & IOL Research Center, Ahmedabad, India.

METHOD

This clinical prospective study comprised 64 eyes of 64 healthy patients with senile cataract and no other ocular pathology having phacoemulsification and implantation of an AcrySof IOL. The eyes were observed for cell deposits. One week and 1, 3, 6, 12, and 15 months postoperatively, specular reflex was obtained by slitlamp biomicroscopy under x 20 magnification to record the incidence, progression, morbidity, and severity of small and large (including giant) cells on the IOLs.

RESULTS

The highest incidence of small cells was 18.7%. The cell deposits appeared at 1 week, peaked at 1 month, and were gone after 6 months. The severity was never more than grade 2 (5 to 10 cells). The highest incidence of large cells, including giant cells, was 23.4%. The deposits appeared at 1 month, peaked at 3 months, and were gone after 12 months. The severity was never more than grade 2 (3 to 5 cells). The highest incidence of giant cells was 6.2%. The deposits appeared at 3 months and were gone by 15 months. Severity was never more than grade 1 (2 cells). No IOL had cell deposits at the last follow-up (mean 14 months +/- 3.25 [SD]).

CONCLUSIONS

The incidence, and especially the severity, of cell deposits in the Indian population was low. All cell types, including giant cells, disappeared within 12 months. This could reflect the biocompatibility of the AcrySof IOL and the appropriate surgical technique.

Biocompatibility of hydrophilic intraocular lenses

PURPOSE

To assess the biocompatibility of 3 hydrophilic acrylic intraocular lenses (IOLs) by evaluating the postoperative cell reaction on the IOL surface, anterior capsule opacification (ACO) rate, and presence of membrane growth over the anterior IOL surface.

SETTING

University Eye Clinic of Trieste, Trieste, Italy.

METHODS

In this prospective study, 73 patients were randomized to receive 1 of 3 types of hydrogel IOLs after phacoemulsification: Storz Hydroview H60M, Corneal ACR6D, or Ioltech Stabibag. To analyze and photograph the anterior IOL surface, slitlamp biomicroscopy and specular microscopy were performed 7, 30, 90, and 180 days after surgery. Small, epithelioid, and giant inflammatory cell reaction was evaluated. In addition, ACO and membrane growth on the anterior IOL surface were assessed.

RESULTS

Low inflammatory cell adhesion was observed on the anterior surface of all 3 IOLs. The Stabibag group had a significantly higher grade of small inflammatory cell reaction 7 and 30 days after surgery. A significantly higher rate of ACO was observed in the ACR6D group. The Hydroview and ACR6D groups had a significantly higher percentage of membrane growth from the capsulorhexis edge onto the anterior IOL surface than the Stabibag group.

CONCLUSIONS

Clinically, the 3 hydrophilic IOLs behaved in a different manner, showing the different forms of biocompatibility. Results indicate that a different chemical composition determines correspondingly different protein absorption on IOL surfaces. This might result in a different adhesion pattern and spreading of lens epithelial and inflammatory cells.

Cytopathology of explanted intraocular lenses and the clinical correlation

PURPOSE

To study the cytopathological features of explanted intraocular lenses (IOLs) and correlate the features with their clinical presentation.

SETTING

Ocular Pathology Department, Medical and Vision Research Foundation, Sankara Nethralaya, Chennai, India.

METHODS

The study comprised 61 explanted IOLs (48 posterior chamber IOLs and 13 anterior chamber IOLs) removed for the following reasons: pseudophakic bullous keratopathy (36), recalcitrant uveitis (7), retinal detachment (10), endophthalmitis (5), uveitis (7), IOL subluxation (2), and painful blind eye (1). The IOLs were stained with hematoxylin and eosin using a simple cytological technique. The cytopathological features were studied and correlated with the clinical presentations.

RESULTS

The mean time of IOL explantation was 10.1 months after surgery. Twenty-one IOLs had granulomatous and nongranulomatous inflammations and 4, nongranulomatous inflammations. One IOL had fungal filaments on the surface.

CONCLUSIONS

Intraocular lenses can produce both granulomatous and nongranulomatous inflammation. Granulomatous inflammation was the most common in this series. The surface of IOLs explanted because of intraocular infection may show infective agents.

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.

Pit defects on the anterior surface of hydrophilic foldable intraocular lenses

A series of pits varying in depth and size appeared on the anterior surface of hydrogel intraocular lenses (IOLs) soon after they were implanted. In all cases, the pits increased in size but not in number during a 1 year follow-up. The origin of the pit defects is unknown and does not seem related to inflammatory or lens epithelial cell activity. Hydration of the IOL could be a cause even if a manufacturing defect were present. This IOL surface alteration did not seem to impair visual function or cause visual disturbances.

Phacoemulsification in eyes with a small pupil

PURPOSE

To evaluate the intraoperative difficulties and long-term outcome of phacoemulsification through a small pupil using minimal iris manipulation.

SETTINGS

Iladevi Cataract & IOL Research Centre, Ahmedabad, India.

METHODS

This prospective study included 30 consecutive eyes with a maximally dilated pupil size of 4.0 mm or smaller. Except synechiolysis and occasional pupil retraction with a chopper, no iris manipulation was performed. The phacoemulsification technique included creation of deep central space, use of a low aspiration flow rate with appropriate vacuum, and step-by-step chop in situ and lateral separation of the nucleus. Patients were examined 1 day, 1 week, 1 and 3 months, and 1 year postoperatively. Specular microscopy was performed at 1 month and 1 year.

RESULTS

Fourteen eyes had chronic iritis, 12 had glaucoma surgery, 2 had pseudoexfoliation, and 2 had a rigid pupil. Mean follow-up was 13.6 months. Eighteen eyes (60%) had hard cataract. Mean preoperative pupil size was 2.80 mm +/- 0.75 (SD). Mean pupil size before the capsulorhexis was initiated was 4.42 +/- 0.58 mm. The iris was bruised in 10 eyes during cortex removal. Trace amounts of cortex were left in 4 cases. Two eyes had increased intraocular pressure in the early postoperative period. Six patients had a minimal amount of retained viscoelastic material (pseudofibrin), and 2 patients developed a sterile hypopyon. Sixteen eyes had cell deposits on the IOL surface and 12 eyes, fine uveal pigments. In 2 eyes with previous glaucoma surgery and in all eyes with iritis except 2, posterior synechias reformed.

CONCLUSIONS

Successful phacoemulsification was done with minimal or no pupil-widening maneuvers, restoring the preoperative pupil configuration.

Evaluation of giant-cell deposits on foldable intraocular lenses after combined cataract and glaucoma surgery

PURPOSE

To compare the incidence of inflammatory giant-cell deposits (IGCDs) on various foldable intraocular lenses (IOLs) after combined cataract and glaucoma surgery.

SETTING

The Phillips Eye Institute, Minneapolis, Minnesota, USA.

METHODS

In this prospective randomized clinical trial, 128 patients were randomized to receive a single-piece, first-generation silicone lens (n = 36); a 3-piece acrylic lens (n = 40); or 3-piece, second-generation silicone lens (n = 52). All patients had combined phacoemulsification and trabeculectomy with mitomycin-C by 1 surgeon using a standardized technique. Dilated biomicroscopy was used to identify and quantitate IGCDs on the surface of the IOLs using a 6-point grading scale.

RESULTS

Inflammatory giant-cell deposits were identified on 21 of 128 IOLs. Lens design was the most significant risk factor for deposit formation (P =.004). Inflammatory giant-cell deposits were most common in the first-generation silicone plate lens group (33%), less common in the acrylic lens group (15%), and least common in the 3-piece, second-generation silicone group (5.8%). Density of the deposits was significantly greater on the plate lens than the acrylic or the 3-piece silicone lenses (P <.0001). Although IOL design was the most significant risk factor for IGCD formation, other significant risk factors included intraoperative pupil stretch (P =.02) and preoperative miotic use (P =.04).

CONCLUSION

Inflammatory giant-cell deposit formation was significantly greater on first-generation silicone plate IOLs than on acrylic or second-generation silicone IOLs. The deposits were somewhat more common on acrylic IOLs than on second-generation silicone IOLs. However, this difference was not clinically or statistically significant.

Capsule contraction after continuous curvilinear capsulorhexis: poly(methyl methacrylate) versus silicone intraocular lenses

PURPOSE

To evaluate the progressive contraction of the anterior capsule opening after in-the-bag implantation of 2 types of intraocular lenses (IOLs).

SETTING

Department of Ophthalmology, University of Brest, Brest, France.

METHODS

In this prospective study, 32 single-piece poly(methyl methacrylate) (PMMA) (Pharmacia 812 C) and 30 3-piece silicone IOLs with PMMA haptics (Allergan SI-40NB) were implanted in the bag after standardized phacoemulsification performed by the same surgeon. All patients were older than 70 years, and none had zonular weakness. The surface of continuous curvilinear capsulorhexis (CCC) was measured 1, 30, and 150 days postoperatively using a 3 charge-coupled device camera and a digitized computer analysis system.

RESULTS

A significant progressive constriction was observed at 150 days in 70% in the silicone group and 32% in the PMMA group. In addition, CCC contraction was greater in silicone group (P < .05). The mean surface decrease was 4.20 mm2 in the silicone group and 1.53 mm2 in the PMMA group. There was no correlation between sex, age, initial capsulorhexis area, final capsule shrinkage. In some eyes, especially in those with a single-piece PMMA IOL (41%), there was no constriction, but fine changes in the capsule opening were seen.

CONCLUSION

Evolutive anterior capsulorhexis modifications were observed in all patients; however, the contraction rate was statistically higher in the silicone group. These results suggest that silicone IOL implantation should be avoided in eyes at risk for CCC constriction.

Evaluation of teflon-coated intraocular lenses in an organ culture method

An amorphous and transparent form of Teflon is proposed as a coating of polymethylmethacrylate (PMMA) intraocular lenses (IOLs), rendering them highly hydrophobic. We used an organ culture method to evaluate cell adhesion, proliferation, and migration on Teflon-coated IOLs. Corneal explants from 14-day-old chicken embryos were placed on a semisolid culture medium and covered with uncoated PMMA (n = 36) and Teflon-coated PMMA (n = 36) IOLs and two controls, Thermanox (n = 84) and latex (n = 36). After incubation (7 days at 37 degrees C), a digital imaging system was used to measure the areas of the cell migration layers on the materials. The cells were then removed with tripsin-ethylenediaminetetraacetic acid and the cells detached at times up to 75 min were counted (Coulter(R) Multisizer System). The values were used to construct a cell disconnecting curve for each material. The areas of cell migration layers on uncoated and Teflon-coated IOLs were significantly different (p <.05). Cell disconnecting curves demonstrated that cells adhered less strongly to Teflon-coated IOLs than to the other materials. This organ culture method demonstrated that the coating of PMMA IOLs with Teflon AF(R) is correlated with antiadhesive and antiproliferative properties.

Cell biology of posterior capsular opacification

Posterior capsular opacification (PCO), a major complication of modern cataract surgery, necessitates further surgical intervention in 10-50% of patients. PCO results from the growth and transdifferentiation of lens epithelial cells left on the anterior capsule at the time of cataract surgery. These cells proliferate to form monolayers on the capsular surfaces, and such monolayers continue to line the anterior capsule leaflet many years after surgery. Some cells, however, differentiate or undergo a transition to another cell type, and these processes greatly contribute to PCO. Equatorial differentiation of cells to fibre-like structures leads to Soemmerring's ring formation and peripheral thickening of the capsular bag. Closer to the rhexis, cell swelling can result in globular Elschnig's pearls, which may occlude the visual axis. Cells at the rhexis edge and those in the space around the optic appear to undergo epithelial-mesenchymal transition. The resulting cells are fibroblastic in morphology, express the smooth muscle isoform of actin and secrete extracellular matrix containing proteins not normally present in the lens.

Measurement of electrostatic charge on intraocular lenses

PURPOSE

An electronic meter that measures electrostatic charge was designed and built. The hypothesis tested was that an intraocular lens (IOL) attains a charge during handling in the operating theatre and that washing the IOL with balanced salt solution (BSS) would result in a reduction in the surface charge. Once exposed to the air a charged IOL may attract particulate matter to its surface before implantation into the eye.

METHODS

This experiment was performed in the operating theatre under sterile conditions mimicking cataract surgery. The lens box was opened onto a trolley and the lens container opened by a scrubbed assistant. The operator (also scrubbed) removed the lens with MacPherson's forceps. The charge on the lens was then measured without delay, or after the lens had been washed with 1-2 ml of BSS.

RESULTS

The mean charge on unwashed lenses was 1.43 x 10(-10) C (n = 12) and on washed lenses was 0.59 x 10(-10) C (n = 10). The difference in the charges was significant (p = 0.03, unpaired t-test).

CONCLUSION

Washing of an IOL prior to implantation will reduce the surface charge and is therefore also likely to reduce the chance of contamination.

Biocompatibility of poly(methyl methacrylate), silicone, and AcrySof intraocular lenses: randomized comparison of the cellular reaction on the anterior lens surface

PURPOSE

To determine the foreign-body response to three intraocular lens (IOL) biomaterials (poly[methyl methacrylate] [PMMA], silicone, and AcrySof) and use this as an indicator of their comparative biocompatibility postoperatively within the eye.

SETTING

A British teaching hospital eye department.

METHODS

Ninety eyes were prospectively randomized to receive a PMMA, silicone, or AcrySof IOL. All lenses had 6.0 mm optics with PMMA haptics. A standardized surgical protocol was performed by a single surgeon using an extracapsular technique with capsulorhexis; eyes that experienced a surgical complication were excluded. All patients had standardized postoperative medication and follow-up. Specular microscopy of the anterior IOL surface was carried out after pupil dilation on days 1, 7, 30, 90, 180, 360, and 720 to assess small cell and giant cell reactions.

RESULTS

All three IOL types produced a mild degree of nonspecific foreign-body response, which resolved over the study period without detrimental effect. The silicone group had significantly higher small cell counts than the PMMA and AcrySof groups (P = .02); the AcrySof group had significantly lower giant cell counts than the other two groups (P = .003).

CONCLUSION

The three IOL types were sufficiently biocompatible to function in normal eyes with age-related cataracts. However, AcrySof IOLs were associated with lower giant cell counts than PMMA and silicone IOLs and might produce better results in eyes with pre-existing blood-aqueous barrier damage.

Continuous curvilinear capsulorhexis and intraocular lens biocompatibility

PURPOSE

To study the influence of continuous curvilinear capsulorhexis (CCC) on poly(methyl methacrylate) (PMMA) intraocular lens (IOL) biocompatibility.

METHODS

Biocompatibility was assessed by measuring the postoperative blood-aqueous barrier breakdown and the cellular reaction at the anterior capsule-IOL interface. In a prospective study, 30 consecutive eyes, normal except for having extracapsular cataract extraction (ECCE) with CCC by a single surgeon, has laser flare and cell measurements and specular microscopy of the anterior IOL surface at 1 day, 1 week, and 1 and 3 months postoperatively.

RESULTS

In addition to the foreign-body reaction previously described in eyes that had other capsulotomy types, the eyes in this study also had a lens epithelial cell (LEC) reaction. The severity of the foreign-body reaction and postoperative aqueous flare and cells was significantly less in eyes with an intact CCC than in those with rim tears in the capsulorhexis and in those having an ECCE with a linear or can-opener capsulotomy, as previously reported.

CONCLUSIONS

Continuous curvilinear capsulorhexis improves the biocompatibility of PMMA IOLs to a degree that could be of clinical benefit. In eyes with CCC, most cells seen on the anterior IOL surface were LECs.

Comparison of the postoperative inflammatory response in the normal eye with heparin-surface-modified and poly(methyl methacrylate) intraocular lenses

Evidence that poly(methyl methacrylate) (PMMA) is not inert in the eye has led to the introduction of intraocular lens (IOL) surface modification. In this prospective, double-blind, randomized study, we evaluated the effects of heparin surface modification (HSM) on anterior segment inflammation for one year after endocapsular cataract surgery. Fifty-four eyes were randomized to receive an HSM IOL (29 eyes) or a PMMA IOL (25 eyes) and were assessed postoperatively by corneal endothelial photography, laser flare and cell measurements, fluorophotometry, and IOL surface specular microscopy. Corneal endothelial loss, mean aqueous flare and cells, and fluorophotometry did not differ significantly between the groups, although fewer eyes in the HSM group had high flare values on the first postoperative day. The number of giant cells was significantly less in the HSM group for up to one year after surgery. Although there was no statistical difference in overall visual outcome, more patients in the HSM group (17%, 5/29) achieved a postoperative visual acuity of 20/15 than in the PMMA group (0). These results demonstrate that HSM enhances IOL biocompatibility and these effects are detectable in the low-risk, normal eye.