Cellular reactions on heparin surface-modified versus regular PMMA lenses during the first postoperative month. A double-masked and randomized study using specular microphotography

Outcome of cataract surgery in children affected by malignancies other than retinoblastoma with eye-lens radiation exposure

PURPOSE

To describe, retrospectively, the visual outcome, feasibility, and safety of cataract surgery in a pediatric population affected by iatrogenic cataract, secondary to systemic oncological treatment for malignancies other than retinoblastoma.

METHODS

Young patients, affected by radiation-induced cataract, who were referred to the San Paolo Ophthalmic Center in Padova between 2010 and 2017, were included in the study. All patients had previously received radiotherapy and/or chemotherapy treatment for malignancies, between 2004 and 2013. All medical records of infants who underwent cataract surgery were accurately reviewed.

RESULTS

Eighteen eyes out of 11 patients included in the study underwent cataract surgery. The mean age at surgery was 9.7 ± 3.6 years. The interval between tumor diagnosis and cataract development was around 3 years. Mean follow-up after surgery was 15.4 ± 6.3 months. All eyes underwent posterior chamber intraocular lens implantation, posterior capsulotomy, and anterior vitrectomy in one time surgery. No intraoperative complications were shown. Post-operatively, only one eye received laser capsulotomy due to posterior capsule opacification. At the end of follow up, best-corrected visual acuity was 20/20 (LogMAR 0) in all eyes and significantly improved (p < 0.01) compared to baseline.

CONCLUSIONS

Iatrogenic-cataract surgery in pediatric oncological patients is a safe and effective way to improve visual acuity. Posterior capsulotomy and anterior vitrectomy at the time of surgery reduce the rate of posterior lens opacification and guarantee an excellent visual acuity in these patients.

Intraocular lens optic capture in pediatric cataract surgery

Posterior capsule opacification (PCO) remains the most common complication of pediatric cataract surgery despite continuous efforts to reduce its incidence. For this reason, pediatric cataract surgeons have expended considerable effort into preventing and mitigating PCO. The intraocular lens (IOL) optic capture technique has been used for the prevention of PCO after pediatric cataract surgery for more than 20y, but there is still no professional consensus. However, recent research has shown encouraging results. The IOL optic capture technique can be performed without anterior vitrectomy to prevent PCO, even in younger children. The type and characteristics of IOLs used for optic capture technique, the location of IOL and the complications of IOL optic capture in children are here reviewed.

Outcomes of cataract surgery in patients with uveitis: a systematic review and meta-analysis

PURPOSE

To critically assess the evidence base regarding outcomes following cataract surgery in uveitic cases.

DESIGN

Systematic evidence-based review and meta-analysis.

METHODS

A comprehensive search query was performed on MEDLINE, EMBASE, CINHAL, and CENTRAL databases. Relevant publications were identified by reviewing query results and reference list searches.

RESULTS

A total of 89 articles met eligibility criteria. Among uveitic eyes with quiet or mostly quiet uveitis before cataract surgery, 20/40 visual acuity or better (≥20/40) was achieved in 68% following phacoemulsification, 72% following extracapsular cataract extraction, and 40% following pars plana lensectomy. More eyes undergoing cataract surgery with intraocular lens (IOL) implantation than eyes left aphakic achieved ≥20/40 postoperatively (71% vs 52%). Eyes receiving acrylic IOLs or heparin-surface-modified (HSM) polymethylmethacrylate had better visual outcomes than those receiving non-HSM polymethylmethacrylate or silicone IOLs. Active uveitis at the time of cataract surgery was associated with worse visual outcomes. Compared with other uveitis cases, the proportion achieving 20/40 or better post cataract surgery was better for Fuchs heterochromic cyclitis cases and worse for uveitis related to Behçet disease, Vogt-Koyanagi-Harada disease, or sympathetic ophthalmia, and also posterior uveitis in general.

CONCLUSION

Cataract surgery in eyes with uveitis resulted in normal range levels of visual acuity in most cases. The review suggests that preoperative control of uveitis, use of an acrylic or HSM IOL, and a diagnosis of Fuchs heterochromic cyclitis were associated with better outcomes. Posterior-involving uveitides tended to do worse, likely because of vision-limiting complications of uveitis. Average results may not be applicable to specific clinical scenarios.

Cataract and glaucoma surgery in pseudoexfoliation syndrome: a review

Pseudoexfoliation syndrome is a risk factor in cataract surgery because of the increased weakness of zonular apparatus and reduced pupillary dilatation. The surgical outcome of using phacoemulsification in the central zone, inducing minimal stress on the zonules, inserting a capsular tension ring in selected cases, and stretching the pupil mechanically in eyes with miotic pupils, may turn out to be uneventful in most cases. Postoperative fibrosis with subsequent shrinkage of the capsule is increased in these eyes, and these centripetal forces will further loosen the zonular fibres. Late in-the-bag intraocular lens dislocation is therefore anticipated to become a growing problem in the future. Despite the dysfunctioning of the blood-aqueous barrier in eyes with pseudoexfoliation syndrome, the frequency of postoperative inflammatory reaction is low due to the improvements made in surgical technique and equipment in recent years. Glaucoma frequently occurs in eyes with pseudoexfoliation syndrome. Compared with primary open-angle glaucoma, optic damage is more pronounced in these eyes at the time of diagnosis and response to medical therapy is poorer. Although responses to argon laser therapy and filtering surgery are roughly similar between the two types of glaucoma, there are indications that primary laser trabeculoplasty has a higher success rate in pseudoexfoliation glaucoma than in primary open-angle glaucoma.

Two-photon absorption-controlled multidose drug release: a novel approach for secondary cataract treatment

Tens of millions of cataract surgeries are done every year and the number is increasing heavily. Posterior capsule opacification is the major postoperative complication with an incidence of 10 to 50% within 5 years, depending on the age of the patient. We present a novel approach for secondary cataract treatment in a noninvasive manner. Photochemically triggered drug release from a polymer enables repeated drug applications for cataract treatment years after implantation of the intraocular lens, just when needed. However, light in the visible spectral range must pass through the lens but must not induce drug release. We demonstrate that two-photon absorption photochemistry is a powerful tool to overcome this problem. With wavelengths in the visible regime, a photochemical reaction that requires energies in the UV is triggered. The high intensities needed for this process never occur in any lighting condition in daily lives, but may be easily obtained with focused laser beams routinely used in ophthalmology. The properties of the therapeutic system are specified and the function is demonstrated by in-vitro cell tests. Noninvasive multidose photochemically triggered drug release from implanted intraocular lenses carrying a drug depot may be a therapeutic as well as an economic choice to established treatments of secondary cataracts.

Hydrophobic acrylic versus heparin surface-modified polymethylmethacrylate intraocular lens: a biocompatibility study

BACKGROUND

The implant of intraocular lenses (IOLs) following cataract surgery induces a foreign-body reaction to the IOL and a response on the part of the lens epithelial cells (LECs). The purpose of this study was to compare these aspects after the implantation of two different IOL materials.

METHODS

Thirty-six cataract patients were randomised to receive two different foldable lens: an acrylic hydrophobic IOL (Acrysof MA30BA) and a heparin surface-modified (HSM) polymethylmethacrylate IOL (Pharmacia & Upjohn 809C) after phacoemulsification. Slit-lamp biomicroscopy with specular technique was used to assess the inflammatory cell adhesion on the anterior IOL surface, anterior capsule opacification (ACO) and membrane growth from the rhexis edge at 7, 30, 90, 180 and 360 days after surgery.

RESULTS

The 809C group showed a higher percentage of patients with slight inflammatory cell adhesion on the anterior cell surface and a higher small cellular density during the whole follow-up period. The epithelioid cell response was greater in the 809C group than the Acrysof group but the difference between the two groups was not statistically significant. The ACO increased during the follow-up in both groups but was significantly higher in the 809C group.

CONCLUSION

Acrysof lenses are more biocompatible than HSM IOLs, showing a lower grade of inflammatory cell adhesion and ACO. The implantation of these lenses may be particularly indicated in patients with pathologies predisposing to blood-aqueous barrier damage.

Effects of dexamethasone, diclofenac, or placebo on the inflammatory response after cataract surgery

AIM

To compare the inflammatory response after phacoemulsification and intraocular lens (IOL) implantation using postoperative treatment with dexamethasone, diclofenac, or placebo.

METHODS

A prospective, randomised, controlled double masked study including 180 patients enrolled for cataract surgery. The patients were 64-85 years old and had no eye disease other than cataract. After phacoemulsification and IOL implantation the patients were randomised to topical treatment with dexamethasone phosphate 0.1% (group I), diclofenac sodium 0.1% (group II), or placebo (saline 0.9%) (group III). The drops were administered four times daily during the first week and twice daily during the second, third, and fourth weeks. The inflammatory reaction in the anterior chamber was measured with laser flare photometry preoperatively and 1, 3, and 8 days, 2 and 4 weeks, 2 and 6 months, and 1, 2, and 4 years postoperatively. Inflammatory symptoms were registered. Biomicroscopy and visual acuity determinations were performed. The rate of Nd:YAG laser posterior capsulotomies after 2 and 4 years was determined.

RESULTS

After 3 and 8 days (p <0.0001), 2 weeks (p <0.0001), and 1 month (p = 0.0013) median flare was highest in group III. There were no significant differences between group I and II. Inflammatory symptoms and striate keratopathy were more common in group III.

CONCLUSION

Dexamethasone and diclofenac were equally effective in reducing postoperative inflammation after phacoemulsification and IOL implantation in eyes with no other disease than cataract. Both substances were more effective than placebo.

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.

[History of the development of intraocular lenses]

Even though cataract surgery has been practiced for over 2000 years, modern cataract surgery started just some 50 years ago. with the first IOL implantation by Sir Harold Ridley. The development of intraocular lenses was accompanied by great successes and disasters. With the fast development of cataract surgical techniques over the past 15 years (ECCE, Phacoemulsification, Capsulorhexis) a successful marriage between IOL-developments and surgery was established. Indication profiles for cataract surgery and IOL implantation extended to more and more patient groups. At this time classical cataract surgery is further developing into refractive intraocular lens surgery to correct higher ametropia in clear lens or phakic eyes. This development was only possible because of the improvements of surgical techniques and implants in classical cataract surgery.

Determination of heparin on intraocular lens surfaces by ion chromatography

A sensitive and selective method has been developed for the determination of heparin on heparin coated PMMA, poly(methyl methacrylate), intraocular lenses. Heparin was hydrolysed to glucosamine and glucuronic acid, and the content of glucosamine was determined using ion chromatography with pulsed amperometric detection. In order to verify that a complete hydrolysis was obtained for the heparin on the coated intraocular lenses, electron spectroscopy for chemical analysis (ESCA) was used for analysing traces of sulphur on the lens surfaces. The sensitivity of the method allows quantitative determination of 150 ng of heparin on one individual lens. The new method was compared to a standard spectrophotometric method, measuring the colour intensity of a heparin toluidine blue complex. Correlation between the methods was shown for samples prepared from PMMA lenses coated with different amounts of heparin.

Inflammatory cell adhesion and surface defects on heparin-surface-modified poly(methyl methacrylate) intraocular lenses in diabetic patients

PURPOSE

To evaluate the incidence of surface scratches on heparin-surface-modified (HSM) poly(methyl methacrylate) (PMMA) intraocular lenses (IOLs) and the possible influence of these alterations on the biocompatibility of HSM PMMA.

SETTING

University Eye Clinic of Trieste, Trieste, Italy.

METHODS

Twenty-six diabetic patients had phacoemulsification and implantation of an HSM PMMA IOL (809C, Pharmacia & Upjohn). Patients with proliferative diabetic retinopathy or iridopathy were excluded from the study. On postoperative days 7, 30, 90, and 180, specular microscopy was performed to study and photograph the anterior IOL surface. The presence of scratches on the anterior IOL surface was assessed and the inflammatory cell reaction noted and graded using a semiquantitative scale. Finally, the location of the inflammatory cells in relation to the surface scratches was established.

RESULTS

Scratches and other surface defects were found in 88.4% of cases. All patients had small cells on the IOL surface 7 days after surgery. At 30 days, small cells were observed in 88.4% of cases. The inflammatory cells were mainly located inside the scratches rather than throughout the IOL surface.

CONCLUSIONS

This in vivo cytology study provides further evidence of the effectiveness of heparin surface modification in improving the biocompatibility of PMMA. In diabetic patients, inflammatory cells adhered to the exposed PMMA surface more than to the HSM surface, suggesting that the use of HSM PMMA in patients with conditions predisposing them to increased postoperative blood-aqueous barrier breakdown is beneficial.

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.

Interaction between inflammatory cells and heparin-surface-modified intraocular lens

PURPOSE

To investigate the interaction and adherence of inflammatory cells to a heparin-surface-modified intraocular lens (HSM IOL).

SETTING

Department of Ophthalmology, Tokyo Medical University Hospital, Tokyo, Japan.

METHODS

Splenic mononuclear leukocytes from rats with experimental autoimmune uveitis were cultured with the optic of an HSM IOL for 96 hours. The number of adherent cells on the HSM IOL surface was measured with and without the addition of interphotoreceptor retinoid-binding protein and concanavalin A (ConA) to the culture medium. The adherent cells were observed under a light microscope or a scanning electron microscope.

RESULTS

Interphotoreceptor retinoid-binding protein and ConA increased the number of adherent cells on the HSM IOL relative to the control. Adherent cells on the HSM IOL were small and round, considered to be mainly lymphocytes.

CONCLUSION

Activated lymphocytes tended to adhere to the surface of the HSM IOL.

Effect of heparin-surface-modified intraocular lenses on postoperative inflammation after phacoemulsification: a randomized trial in a United States patient population. Heparin-Surface-Modified Lens Study Group

OBJECTIVE

To compare postoperative inflammation occurring with heparin-surface-modified (HSM) versus non-HSM polymethyl methacrylate intraocular lenses (IOLs) after phacoemulsification.

DESIGN

Randomized, double-masked, multicenter, parallel trial.

PARTICIPANTS

A total of 367 patients, consisting of routine (n = 220), glaucoma (n = 58), and diabetes (n = 89) patients, from eight US medical centers.

METHODS

Patients were observed for 1 year after phacoemulsification and lens implantation (week 1, months 1, 3, 6, 12).

MAIN OUTCOME MEASURES

Primary measures of postoperative inflammation defined as the presence of giant cells on the lens surface via specular micrography and cellular deposits via slit-lamp examination.

RESULTS

The cross-sectional analyses showed that consistently fewer routine patients with HSM lens implants had giant cells on the IOL than those with non-HSM lens implants across all follow-up visits. The statistical significance (P < 0.05) was observed at all visits except month 12 for routine patients. The diabetes patients also demonstrated the same giant cell difference, and the statistical significance was observed at all visits including month 12. A similar trend was also observed in the glaucoma patients, with statistical significance only at the 3-month visit. For cell deposits, significant differences in favor of the HSM lens (P < 0.05) were observed at 3 months among routine and diabetes patients, and at 3 and 6 months among glaucoma patients. A longitudinal data analysis using the generalized estimating equation approach indicated statistically significant treatment effect of HSM lenses in reducing inflammation in all patients except for cellular deposits in diabetes patients. In all patient groups, sight-threatening complications were not reported either more frequently or with more severity than normally expected for patients who have undergone cataract extraction and IOL implantation.

CONCLUSIONS

The present study, the only one to have used phacoemulsification in virtually all patients (211/220 [96%] routine, 57/58 [98%] glaucoma, and 84/89 [94%] diabetes) is the largest to evaluate and compare concurrently routine, glaucoma, and diabetes patients. It is also the first US patient population study to document that heparin surface modification reduces postoperative inflammatory responses, as measured by specular micrography and slit-lamp examination, especially in the early postoperative period.

Evaluation of foldable intraocular lenses in patients with uveitis

OBJECTIVE

To evaluate various foldable posterior chamber intraocular lenses (IOLs) after phacoemulsification in patients with uveitis.

DESIGN

A prospective, noncomparative, interventional case series.

PARTICIPANTS

Forty-nine consecutive patients (60 eyes) with various types of uveitis (anterior, n = 20; posterior, n = 1; panuveitis, n = 37, intermediate, n = 2).

INTERVENTION

All patients underwent phacoemulsification with foldable posterior chamber IOL implantation. All eyes were free of active inflammation at the time of surgery. A variety of IOL biomaterials were implanted: acrylic (n = 30), silicone (n = 17), and hydrogel (n = 13).

MAIN OUTCOME MEASURES

Detailed examination was performed by one masked observer. Several parameters were compared for each implant biomaterial, including level of best corrected Snellen visual acuity at final follow-up, presence of posterior synechiae, anterior capsular phimosis, posterior capsule opacification, and the degree of cellular deposits on the IOL optic.

RESULTS

There were 26 males and 23 females, aged 9 to 83 years (mean, 48 years). Follow-up ranged from 1 to 33 months (mean, 17.03 months). At final follow-up, 56 eyes (93.3%) had an improvement in visual acuity compared with preoperative levels as follows: 34 eyes (56.6%) achieved an improvement of four or more Snellen lines, and 44 eyes (73.3%) achieved 20/30 or better. Giant cells, observed on the IOL optic in 19 eyes (31.7%), were most often seen on the acrylic biomaterial at the 1-month follow-up, although this was not found to be statistically significant. Scratch marks produced by the lens-introducing forceps were seen in 24 eyes (40.0%), mainly on the acrylic and hydrogel optics. Posterior capsule opacification (PCO) occurred in 49 eyes (81.7%), with only 5 eyes requiring laser capsulotomy. There was no association between PCO and the various lens biomaterials. Other causes for reduced visual acuity included glaucomatous optic neuropathy (n = 5) and cystoid macular edema (n = 8).

CONCLUSIONS

The use of foldable IOLs in eyes with uveitis is safe, but the optimal biomaterial has yet to be found.

Adhesion of soluble fibronectin, laminin, and collagen type IV to intraocular lens materials

PURPOSE

To evaluate soluble fibronectin, laminin, and collagen IV adhesion to poly(methyl methacrylate) (PMMA), heparin-surface-modified (HSM) PMMA, silicone, acrylate, and hydrogel intraocular lenses (IOLs).

SETTING

Department of Medical Biochemistry, University of Oulu, Oulu, Finland.

METHODS

Seventy-five IOLs were incubated for 24 hours at 37 degrees C with radioactive iodine labeled soluble fibronectin, laminin, or collagen type IV. Twenty-five IOLs were analyzed for each protein, 5 of each type. The amount of absorbed protein was measured with a gamma counter and expressed as counts per minute (cpm).

RESULTS

Fibronectin bound best to the acrylate IOL; the differences between the acrylate and the other materials, except PMMA, were significant (P < .01 to .001; PMMA P = .31). Although significantly more laminin bound to acrylate than to PMMA, HSM PMMA, or silicone (P < .05 to .001), hydrogel had the highest overall binding of this protein (P < .001 to .0001). Hydrogel also had significantly higher binding of type IV collagen than the other IOLs (P < .01 to .0001).

CONCLUSIONS

It can be hypothesized that if an IOL has more fibronectin bound to it, the IOL can also attach to the capsule better as it consists mainly of collagen. The stronger binding of fibronectin and laminin to acrylate IOLs could be an explanation for the better adhesion of the acrylate IOL to the anterior and posterior capsules and thus for the lower rate of posterior capsule opacification.

Heparin-surface-modified intraocular lenses in pediatric cataract surgery: prospective randomized study

PURPOSE

To evaluate the performance of heparin-surface-modified (HSM) intraocular lenses (IOLs) in pediatric eyes after cataract surgery.

SETTING

L.V. Prasad Eye Institute, Hyderabad, India.

METHODS

This prospective, randomized, double-masked, controlled clinical trial comprised 90 children aged 2 to 14 years with cataract. The patients were consecutively randomized to receive an HSM (Group 1) or an unmodified (Group 2) poly(methyl methacrylate) (PMMA) IOL. Extracapsular cataract extraction (ECCE) with IOL implantation was performed in children 8 years and older and ECCE with primary posterior capsulotomy, anterior vitrectomy, and IOL implantation in children younger than 8 years. Outcome parameters were inflammatory cell deposits on the IOL surface, posterior synechias, and anterior chamber reaction.

RESULTS

Follow-up data were available for 73, 70, 60, and 68 patients at 1 week, 1 month, 3 months, and 6 months, respectively. Significantly fewer cell deposits were noted in Group 1 at 1, 3, and 6 months (P < .001). Synechia formation and anterior chamber reaction were comparable in the 2 groups.

CONCLUSION

The lower incidence of inflammatory cell deposit formation in eyes with HSM PMMA IOLs indicates that these IOLs have greater bicompatibility than unmodified IOLs in pediatric cataract surgery.

Endophthalmitis after cataract surgery: risk factors relating to technique and events of the operation and patient history: a retrospective case-control study

OBJECTIVE

This study aimed to investigate the relationship between postoperative endophthalmitis and current changes in the cataract operative technique.

DESIGN

A retrospective case-control study.

PARTICIPANTS

The 22,091 cataract operations performed from 1990 through 1993 at St Eriks Hospital formed the basis for this investigation. In a random fashion, 220 control subjects were selected to be compared with the endophthalmitis cases.

MAIN OUTCOME MEASURES

Numerous variables pertaining to the cataract extraction procedure and to the ocular and general health of patients with cataracts were analyzed regarding the development of postoperative intraocular infection. Patient age, presence of diabetes or immunosuppression, type of cataract extraction and intraocular lens (IOL), and intraoperative or postoperative complications were the principal variables assessed.

RESULTS

Fifty-seven patients with endophthalmitis were diagnosed, resulting in an overall frequency of 0.26%. Immunosuppressive treatment (P = 0.019), wound abnormality (P = 0.03), and the use of IOLs without a heparinized surface (P = 0.0023) were the only significant risk factors found in a logistic regression model.

CONCLUSIONS

The results suggest that cataract operating practice may alter the risk for endophthalmitis in that implanting a heparinized IOL and creating a tight section both seem to provide protection against this dreaded complication. Regarding patient history, an increased susceptibility was found among subjects treated with immunosuppressants. Designing a prophylactic protocol that protects against endophthalmitis more efficiently than did the study prophylaxis of 20 mg of subconjunctival gentamicin, is important not only for this patient subgroup but also for the cataract operated population at large.

Lens epithelial cell regression on the posterior capsule with different intraocular lens materials

BACKGROUND/AIMS

Posterior capsular opacification (PCO) is caused by proliferation and migration of lens epithelial cells (LECs) across the posterior capsule and is the commonest cause of reduced vision after cataract surgery. The influence of intraocular lens (IOL) material on the process of LEC migration was studied.

METHODS

90 eyes underwent standardised extracapsular surgery, with capsulorhexis and "in the bag" IOL placement. They were randomised to receive a three piece 6 mm lens of PMMA, silicone, or polyacrylic (AcrySof, Alcon, Fort Worth, TX, USA). On days 7, 30, 90, 180, and years 1 and 2 high resolution digitised retroillumination images were taken of the posterior capsule. The presence of LECs was determined at 90 days and 2 years, and their progression or regression was established by serial examination of images.

RESULTS

LECs were seen in 93% of silicone and 97% of PMMA IOLs at 90 days, compared with 46% of polyacrylic (p < 0.001). At year 2 LECs were present in all patients with silicone or PMMA lenses, whereas 62% of patients with polyacrylic IOLs had LECs (p < 0.001). Of those patients with LECs at day 90 LEC regression occurred in 8% with silicone IOLs and 15% of PMMA cases, compared with 83% of patients with polyacrylic IOLs (p < 0.0001).

CONCLUSION

The presence of LECs on the posterior capsule was considerably lower with polyacrylic than PMMA or silicone IOLs and LEC regression occurred more frequently. The lower incidence of LECs and the higher rate of regression may explain why PCO formation appears to be reduced with polyacrylic lenses. This has important clinical implications for the prevention of PCO.

Posterior capsule opacification and neodymium: YAG capsulotomy with heparin-surface-modified intraocular lenses

PURPOSE

To compare the effect of heparin-surface-modified (HSM) and conventional unmodified poly(methyl methacrylate) (PMMA) intraocular lenses (IOLs) on the formation of posterior capsule opacification (PCO).

SETTING

Department of Ophthalmology, Vejle Hospital, Denmark.

METHODS

This prospective, randomized, double-blind study comprised 250 eyes of 246 patients who had uneventful extracapsular cataract extraction in otherwise healthy eyes with implantation of a biconvex IOL or a convex-plano lens with a continuous laser ridge. Patients were examined once a year for 3 years, at which time the degree of PCO was recorded. A neodymium:YAG laser capsulotomy was performed if certain criteria were met.

RESULTS

The incidence of PCO was statistically significantly higher in eyes with an HSM convex-plano laser-ridge IOL than in those with an unmodified convex-plano lens (P < .005). There were no significant differences between any other groups.

CONCLUSION

The incidence of PCO was higher in eyes with an HSM convex-plano IOL with a laser ridge.

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.

Intraocular lens materials and styles: a review

Biomaterial science has lead to the development of a variety of foldable intraocular lens (IOL) biomaterials. This literature review examines these lenses from both a basic science and a clinical perspective. By most parameters, hydrogel, soft acrylic and silicone IOL are better than polymethylmethacrylate (PMMA) lenses. Plate haptic silicone IOL have the lowest incidence of cystoid macula oedema and posterior capsule opacification, but these lenses require an intact anterior capsularhexis and posterior capsule. Yttrium aluminium garnet (YAG) laser capsulotomy must be delayed at least 3 months to avoid posterior lens dislocation. Silicone has the lowest threshold for YAG laser damage of all IOL materials and also adheres irreversibly to silicone oil with subsequent optical impairment. Three piece silicone IOL with polypropylene haptics have a higher incidence of decentration, pigment adherence and capsule opacification compared with PMMA haptics. Hydrogel lenses are very biocompatible and resistant to YAG laser damage, but pigment adheres to the surface more readily than PMMA. Soft acrylic IOL unfold slowly, resulting in controlled insertion, but it is possible to crack the lens and some lenses develop glistenings due to water accumulation. There are significant socioeconomic implications to the large differences in posterior capsule opacification rates between the various biomaterials and the lens styles.

The effect of heparin-coated intraocular lenses on intraocular pressure following combined trabeculectomy and cataract surgery

PURPOSE

To review the effects on intraocular pressure control of the use of standard and heparin-coated intraocular lenses (IOLs) following combined cataract and glaucoma surgery after a minimum period of 2 years.

METHODS

Case note review of all patients with glaucoma who required cataract extraction combined with trabeculectomy and who were randomized to either of the two IOL types. The number of ocular hypotensive medications and the intraocular pressures were recorded pre-operatively and at 3, 6, 18 and 24 months following surgery.

RESULTS

The two groups (9 receiving standard IOLs and 10 heparin-coated IOLs) were comparable for age, sex and follow-up, as were the pre-operative intraocular pressures and number of treatments. Post-operatively, all patients achieved an intraocular pressure < 21 mmHg at the final visit, with only one patient in each group requiring topical medication, but the standard lens group had a higher intraocular pressure at 2 years (p<0.05). The magnitude of the fall from the pre-operative values was greater in the heparin-coated lens group at 2 years after surgery (p<0.02). The presence of a visible drainage bleb occurred equally frequently in the two groups.

CONCLUSIONS

Use of a heparin-coated IOL does not adversely affect the intraocular pressure control following combined cataract and drainage surgery. The greater fall in intraocular pressure at 2 years in those receiving a heparin-coated IOL may have occurred by chance.

Cellular reaction on the anterior surface of poly(methyl methacrylate) intraocular lenses

PURPOSE

To assess the cellular reaction on the anterior surface of poly(methyl methacrylate) (PMMA) intraocular lenses (IOLs) implanted by phacoemulsification with continuous curvilinear capsulorhexis (CCC) or by extracapsular cataract extraction (ECCE) with a linear capsulotomy.

SETTING

Cataract and Refractive Surgery Research Unit. Department of Ophthalmology, St. Thomas' Hospital, London, United Kingdom.

METHODS

To document morphology, topography, and severity of the cellular reaction, specular microscopy of the anterior IOL surface was performed at 1 day, 1 week, and 1 and 3 months postoperatively in two parallel groups of 31 consecutive cataractous eyes operated on by phacoemulsification with CCC or by ECCE with a linear capsulotomy.

RESULTS

The local tissue response consisted of a nonspecific foreign-body reaction to the IOL and a lens epithelial cell reaction. The foreign-body reaction was significantly less severe in the phacoemulsification group than in the ECCE group, and the number of IOLs without inflammatory cells was significantly higher.

CONCLUSION

The foreign-body reaction to PMMA IOLs is significantly reduced when the lens is implanted by phacoemulsification with CCC. This could be of clinical benefit in high-risk eyes prone to the inflammatory complications of cataract surgery.

Correlation between intraocular lens hydrophilicity and anterior capsule opacification and aqueous flare

PURPOSE

To study the correlation between a basic parameter of intraocular lens biocompatibility, hydrophilicity, and two clinical parameters, postoperative inflammation and anterior capsule opacification.

SETTING

Miyake Eye Hospital, Nagoya, Japan.

METHODS

Three combinations of IOLs that were identical in shape but had distinct contact angles of water were used in this prospective double-masked study: (1) experimental comparison of collagen type IV and poly(methyl methacrylate) (PMMA) IOLs in rabbit eyes; (2) clinical comparison of heparin-surface-modified and PMMA IOLs; (3) clinical comparison of three foldable IOLs, silicone, acrylic, and memory. One of the two IOLs being compared in each situation was randomly assigned to both eyes of each animal or patient. At 1 and 3 months postoperatively, the degree of anterior capsule opacification and the amount of flare in the anterior chamber were determined.

RESULTS

In all three comparative situations, greater postoperative inflammation and more rapid anterior capsule opacification was seen in the eyes with hydrophobic IOLs.

CONCLUSION

There was a correlation between the hydrophilicity of an IOL and the severity of postoperative inflammation and the speed of anterior capsule opacification.

A retrospective analysis of heparin-surface-modified intraocular lenses versus regular polymethylmethacrylate intraocular lenses in patients with uveitis

BACKGROUND

Several studies described the benefits of the heparin-surface-modified intraocular tens (HSM IOL) with regard to the reduced inflammation in routine extracapsular cataract extractions. However, limited information is available about the advantages of the HSM IOL in patients with an intraocular inflammation.

AIM

To assess the eventual benefits of the HSM IOL compared to the regular polymethylmethacrylate intraocular lens (PMMA IOL) in patients with uveitis.

METHODS

A retrospective study of 43 patients with uveitis of various origins who underwent an extracapsular cataract extraction (24 with HSM, 19 with PMMA IOL). The activity of intraocular inflammation, visual acuity, eventual complications, and medications were examined. Standardized follow-up dates were used (before surgery, one and fourteen days, five and eleven months after surgery.)

RESULTS

No difference in the inflammatory, activity was noted between HSM and PMMA groups; neither at short term clinical evaluation, nor at five months after surgery. Despite a slightly better visual acuity in the HSM group before surgery, no long term differences were observed. After surgery the increase in visual acuity was similar for both groups, as well as the frequency of cystoid macular oedema (CMO) and synechiae. Fewer patients in HSM group required Nd:YAG posterior capsulotomy, but the difference was not significant.

CONCLUSION

No clinical advantage was found when the HSM IOL was compared with the regular PMMA IOL in 43 patients with uveitis.

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.

Natural history of cellular deposits on the anterior intraocular lens surface

Previous cytopathological studies have demonstrated the presence of cellular deposits on the poly(methyl methacrylate) (PMMA) intraocular lens (IOL) surface. In this prospective study, IOL surface specular microscopy was used to document the natural history of these deposits in the first year following PMMA IOL implantation. Intraocular lens surface specular microscopy was performed 1, 3, 6, and 12 months after endocapsular cataract surgery in 27 otherwise normal eyes. Postoperatively, IOLs were assessed for the presence of inflammatory cells, with the number of cells graded from 0 (none) to 4 (many). Two inflammatory cell types were visualized: small and giant cells. Small cells were found on 81.5% of IOLs at 1 month, 73.1% at 3 months, and 30.4% at 12 months. Small cells were found in only small numbers (peak mean cell score of 1.26 +/- 0.94 at 1 month). Giant cells were found on 59.3% of lenses at 1 month, 73.1% at 3 months, and 39.1% at 12 months. The number of giant cells on each lens peaked at 3 months (mean cell score 2.0 +/- 1.55), when 50% of lenses achieved a giant cell score of 3 or 4. Inflammatory cell deposits are, therefore, a normal occurrence on the PMMA IOL surface for up to 1 year after surgery. This cellular response consists of two distinct processes: a small cell response, which peaks by 1 month, and a later giant cell response, which peaks at 3 months.

Inflammation after cataract extraction and intraocular lens implantation in patients with rheumatoid arthritis

AIMS

The purpose of this study was to examine whether preoperative activity of rheumatoid arthritis influences the extent of anterior chamber inflammation after cataract extraction and intraocular lens implantation.

METHODS

The medical records of 23 consecutive patients (33 eyes) with rheumatoid arthritis, who underwent cataract extraction with intraocular lens implantation, were reviewed during a 4 year period from April 1990 to March 1994.

RESULTS

Eleven patients who still showed a 1+ level of aqueous cells 1 month after the surgery had significantly higher titres of rheumatoid factor preoperatively, compared with the other 12 patients who showed no aqueous cells (p = 0.0019, Mann-Whitney U test). The persistence of aqueous cells also had a significant correlation with extracapsular cataract extraction compared with phacoemulsification (p = 0.0391, chi 2 test). Multivariate analysis showed that the titre of rheumatoid factor was the more significant element to determine the persistent aqueous inflammation. All the eyes, except for four which had a macular hole, optic disc atrophy, or retinitis pigmentosa gained visual acuity of 20/30 or better. The aqueous cells cleared 3 months after the surgery and left no complications in any of the eyes.

CONCLUSION

Intraocular lens implantation is basically a safe procedure for patients with rheumatoid arthritis, although postoperative aqueous inflammation tends to be persistent in patients with high titres of rheumatoid factor.

Correlations between aqueous flare and cells and lens surface cytology in eyes with poly(methyl methacrylate) and heparin-surface-modified intraocular lenses

A prospective, single-surgeon study was performed on 59 patients randomized to receive a poly(methyl methacrylate) intraocular lens or a heparin-surface-modified lens after standardized endocapsular cataract surgery with a routine postoperative regimen. The anterior chamber laser flare and cell measurements and the cellular reaction on the anterior lens surface were monitored for a year following surgery. This report examines the correlations between the anterior chamber flare and cell reaction and the anterior IOL surface cellular reaction. The findings suggest that the early postoperative blood-aqueous barrier breakdown is primarily caused by surgical trauma; by one month the blood-aqueous barrier function is determined by inflammatory mediators released by small monocyte-derived cells on the IOL surface. Giant cells on the IOL surface did not correlate with aqueous flare, which suggests an insignificant capacity to release inflammatory mediators.

Heparin-surface-modified intraocular lens implantation in patients with glaucoma, diabetes, or uveitis

We investigated the clinical outcome in two groups of patients who had an extracapsular cataract extraction and implantation of a heparin-surface-modified intraocular lens (HSM IOL) (Group 1) or a conventional poly(methyl methacrylate) (PMMA) lens (Group 2). Nineteen patients in Group 1 had bilateral cataract extraction with implantation of an HSM IOL in one eye and a conventional lens in the fellow eye. All patients had glaucoma, diabetes, or uveitis. Over the long term, there was no statistically significant difference between groups in visual acuity, corneal edema, anterior chamber reaction, and amount of posterior synechia formation and IOL deposits. Yet short-term clinical evaluation revealed significantly less reaction in eyes with the HSM IOL than in those with the PMMA lens. In patients with both lens types implanted, early postoperative anterior chamber reaction was less and IOL deposits fewer in the eye with the HSM IOL.

Cell reaction and pigment deposits on the posterior chamber intraocular lens

Cellular reaction and pigment deposits on the intraocular lens were evaluated by biomicroscopy in 220 eyes which had undergone estracapsular cataract extraction and implantation of a posterior chamber intraocular lens 3 months previously. No cells or pigment were observed on the intraocular lens in 32% of the eyes, while small cells and/or pigment were found in 32% and giant cells with or without pigment and small cells were seen in 35%. In a sample of 28 eyes the clinical findings correlated with the findings in specular microphotographs. The corresponding percentages were 32, 36 and 32% in biomicroscopy and 14, 36 and 50% in specular microphotography. The giant cell reaction was notably (p < 0.001) associated with the presence of exfoliation. Previous ocular diseases and operations did not increase the frequency of cellular reaction.

Specular microscopy of the anterior intraocular lens surface

Until recently the cytological assessment of the intraocular lens (IOL) surface was only possible using in vitro cytopathological techniques on explanted lenses or in animal models. Specular microscopy provides an in vivo method for the observation of the IOL surface at high magnification. We have used this technique to examine the IOL surface of 27 normal pseudophakic eyes in the first 3 months following implantation. Cellular deposits consisting of small and giant inflammatory cells were found to be a normal occurrence in otherwise clinically successful cataract surgery. It was also possible to visualise the anterior capsule and its attachment to the IOL surface, an amorphous surface membrane, pigment, surface contaminants (starch granules and fibres), and the markings caused by instrumentation at the time of implantation. The technique of IOL surface specular microscopy therefore provides a useful method for the visualisation of the IOL surface and the cytological reaction that occurs there, and thus allows an assessment of IOL biocompatibility.

Biocompatibility of surface-modified intraocular lenses

We evaluated the biocompatibility of three kinds of intraocular lenses: heparin-surface-modified, surface-passivated, and regular poly(methyl methacrylate). Each lens type was implanted in 30 eyes. The cases were followed for one year. Biocompatibility was assessed by the degree of postoperative inflammation and capsule opacification. There was no significant difference between the surface-passivated and regular groups on both indices, but there was less postoperative inflammation in the heparin-surface-modified group. The incidence of posterior capsule opacification was greater in the heparin-surface-modified group than in the surface-passivated and regular groups, but the difference was not statistically significant.

Comparing the cell population on different intraocular lens materials in one eye

We developed a method to evaluate cell adherence to different intraocular lens (IOL) materials in one eye in which we coated one half of the anterior surface of a poly(methyl methacrylate) (PMMA) IOL with poly(dimethyl siloxane), a silicone material. The lenses were implanted in the anterior chamber of rabbit eyes without lens extraction. Postoperative cellular reaction on the IOL surfaces was studied by specular microscopy. The IOLs were fixed in situ, removed from the eyes, and stained with hematoxylin-eosin so we could evaluate the cell population on the silicone and PMMA surface. Fewer cells were scattered on the silicone surface than on the PMMA surface. This method excludes surgical effects and allows a comparison of various IOL materials in the same eye.