Posterior capsule opacification after cataract surgery in patients with uveitis

PURPOSE: To compare the incidence rate of posterior capsule opacification (PCO) after phacoemulsification and standard extracapsular cataract extraction (P/ECCE) in eyes with antecedent uveitis with the incidence rate in eyes without any history of intraocular inflammation. DESIGN: Review of records of 108 eyes of 78 patients with uveitis and 122 eyes of 106 patients with no uveitis who underwent P/ECCE. Rates of PCO were compared by the log-rank test of differences in the Kaplan-Meier survival curves. Proportional hazards regression models provided estimates of the relative risks of PCO among uveitic compared to nonuveitic eyes. MAIN OUTCOME MEASURES: Performance of neodymium: YAG laser posterior capsulotomy was used as a proxy measure for the main outcome of visually significant PCO. RESULTS: Study patients ranged in age from 6 to 81 years (median, 44.5 years) among those with uveitis and 27 to 96 years (median, 68.5 years) among those without uveitis (P = 0.0001). Crude incidence rates for visually significant PCO were 54% over a mean follow-up of 4.3 years in uveitic cases and 40% over a mean follow-up of 3.9 years among nonuveitic cases (P = 0.02). Estimates of PCO incidence (95% confidence interval) in uveitic eyes derived from the Kaplan-Meier models were 38.5% (range, 28.9%-48.2%) at 1 year and 56% (range, 45.8%-66.3%) at 3 years, and estimates among nonuveitic eyes were 11.5% (range, 6.2%-16.8%) at 1 year and 38.4% (range, 29%-47.8%) at 3 years. These rates of PCO among patients with uveitis and those patients without uveitis differed significantly by the log-rank test (P = 0.004). However, after adjusting for the younger age of patients with uveitis, the rates of PCO were no longer statistically different. CONCLUSIONS: The apparent higher rate of PCO in patients with uveitis is primarily due to their younger age at the time of surgery. A moderately increased independent risk of PCO from uveitis cannot, however, be ruled out by this study.     

Measuring the anterior capsule opening after cataract surgery to assess capsule shrinkage

PURPOSE: To measure anterior capsule opening (ACO) size after acrylic intraocular lens (IOL) implantation and study the natural course of ACO reduction. SETTING: Kimura Eye and Internal Medicine Hospital, Hiroshima, Japan. METHODS: This study comprised 32 patients (38 eyes) having continuous curvilinear capsulorhexis, phacoemulsification, acrylic IOL implantation, and a self-sealing incision performed by 1 surgeon. A retroillumination photograph of the ACO was obtained with the Anterior Eye Segment Analysis System and converted to a computer image. The images were used to measure ACO size postoperatively and calculate the reduction ratio. Follow-up was 6 months. RESULTS: The postoperative reduction ratio in ACO size was 2.14% at 1 week, 3.83% at 1 month, 4.29% at 3 months, and 5.03% at 6 months. In a few cases, the reduction was progressively severe throughout the follow-up. CONCLUSIONS: The anterior capsule opening shrank rapidly during the first month after acrylic IOL implantation, followed by a slower progressive reduction in the subsequent 6 months. When severe, progressive shrinkage occurs, an anterior neodymium:YAG laser capsulotomy should be performed within 2 months postoperatively.     

Cell proliferation on the outer anterior capsule surface after extracapsular lens extraction in rabbits

PURPOSE: To use light microscopy to evaluate the presence and distribution of cells that proliferate on the outer surface of the anterior capsule after experimental lens extraction in rabbit eyes. SETTING: Research Laboratory, Department of Ophthalmology, Wakayama Medical College, Wakayama, Japan. METHODS: Extracapsular lens extraction, with or without implantation of a poly(methyl methacrylate) intraocular lens, was performed in 10 adult albino rabbits under general anesthesia. Animals were killed 1 month postoperatively. Each eye was embedded in paraffin and examined by light microscopy. RESULTS: A capsular bag composed of the anterior and posterior capsules was observed. Mononuclear cells, presumed to be lens epithelial cells (LECs), had proliferated in the space between the capsules as well as on the outer surface of the anterior capsules, in association with an accumulation of extracellular matrix. CONCLUSION: After lens extraction, LECs migrated to and proliferated on the anterior surface of the anterior capsule.     

Extracellular matrix of opacified anterior capsule after endocapsular cataract surgery

BACKGROUND: We determined the types and distribution of glycosaminoglycans (GAGs) and collagens, in anterior capsular opacification after endocapsular phacoemulsification and aspiration (ECPEA) and intraocular lens implantation. METHODS: Opacified anterior capsules were removed from human eyes after ECPEA. Immunohistochemical staining was performed to determine GAGs with monoclonal antibodies to chondroitin, chondroitin-4-sulfate (C4S), chondroitin-6-sulfate (C6S), dermatan sulfate (DS), and keratan sulfate (KS); collagens with monoclonal antibodies to types I, II, and III collagens; and cellular characteristics with monoclonal antibodies to vimentin, desmin, alpha-smooth muscle actin, and cytokeratin. Decorin mRNA and type I collagen mRNA were detected by in situ hybridization. RESULTS: In the capsules, the C6S, DS, KS, and types I and III collagens were similar to the chemical components found at the adhesion site of the anterior and posterior capsules after extracapsular cataract extraction, and cellular components contained vimentin, desmin, alpha-smooth muscle actin, cytokeratin, decorin mRNA, and type I collagen mRNA. CONCLUSIONS: The GAGs and collagens in opacified anterior capsule after ECPEA were similar to those found during wound healing, although KS is present in normal anterior segment tissue during development and only in the cornea postnatally. These chemical components may be produced by myofibroblast-like cells presumably transformed from lens epithelial cells.     

Photographic image analysis system of posterior capsule opacification

PURPOSE: To describe a morphological scoring system of posterior capsule opacification (PCO) that is not based on visual acuity testing. SETTING: Department of Ophthalmology, University of Heidelberg, Germany. METHODS: Following dilation of the pupil, standardized photographs of the pseudophakic anterior segments were obtained using a photo slitlamp. Posterior capsule opacification was scored by evaluating retroillumination photographs. The individual PCO score was calculated by multiplying the density of the opacification (graded from 0 to 4) by the fraction of capsule area involved behind the intraocular lens (IOL) optic. To evaluate the reliability of the morphological scoring system, six observers examined photographs of five eyes each (Experiment A, interindividual reliability). The same observer scored the PCO in three eyes on five different days (Experiment B, intraindividual reliability). RESULTS: Morphological PCO scores were very reliable. With PCO scoring from 0 to 4, the interindividual reliability showed standard deviations between 0.08 and 0.25. The intraindividual reliability showed standard deviations between 0.06 and 0.19 of the mean individual PCO scores. Standard deviation was 0.12 when different photographs of the same eye were scored. CONCLUSION: The morphological scoring system evaluates the entire area behind the IOL optic and thus includes a larger area of the posterior capsule than does visual acuity testing. The method revealed high reliability and insignificant investigator-dependent variations. When using a standardized photographic setup, systematic errors by the photographic technique were not relevant. This method may be an important tool to accurately test for differences in PCO formation with various IOL styles and surgical methods.     

Prevention of posterior capsule opacification with the CO2 laser

BACKGROUND AND OBJECTIVE: Posterior capsule opacification (PCO) is a common complication after cataract extraction, despite the modern surgical techniques and lenses being used for this procedure. Its prevention challenged many investigators, because the current treatment of choice, capsulotomy with Nd:YAG laser, is associated with sight-threatening complications. In the present study, the authors investigated two approaches of preventing PCO using the CO2 laser. MATERIALS AND METHODS: A 15-W CO2 laser with a 17- or 18-gauge hollow probe was used on 20 sheep eyes and 14 rabbit eyes. Lens extraction was done by phacoemulsification. In the equatorial treatment study, the anterior chamber was filled with either air or a viscoelastic substance, and laser burns were applied to the equator of the lens capsule and to the peripheral anterior capsule to destroy the epithelial cells. In the capsulotomy study, a primary posterior capsulotomy was created by delivering 1 to 3 laser shots to the capsule behind an implanted intraocular lens (IOL). RESULTS: The CO2 laser was satisfactory in sheep eyes after filling the anterior chamber with air. In rabbit eyes, however, it was technically impractical to work with air. Using a viscoelastic material to maintain the anterior chamber, the hollow probe of the CO2 laser becomes plugged up and therefore is unable to affect the ocular tissue. However, by combining viscoelastic and air pumping, both the destruction of the lens epithelial cells and the creation of a central posterior opening behind a capsular-fixated IOL was repeatedly achieved. CONCLUSION: Using the CO2 laser for destruction of lens epithelial cells and the creation of controlled posterior capsulotomy is feasible and practical. A different design of the probe (closed gauge) is required to enable it to operate clinically in a fluid or viscoelastic environment.     

The frequency of secondary cataract after extracapsular cataract extraction

A complication of extracapsular cataract extraction is posterior capsule opacification (secondary cataract). In this study we found that 26.0% of patients operated for cataract with extracapsular technique were treated for secondary cataract. The average postoperative time to treatment with Nd-YAG-lasercapsulotomy was 15.2 months with a follow-up time of 34 months.     

Progression of diabetic retinopathy after cataract extraction

A prospective study of the effect of cataract extraction with intraocular lens implantation on the course of diabetic retinopathy (DR) in 44 patients (59 eyes) was carried out. It showed that in the 1-3 years following surgery, there was progression of DR (including development of newly formed retinopathy) in 35% of the patients (28.8% of eyes). Progression was more marked in patients with pre-operative bilateral DR compared to those without bilateral DR (77% and 16% respectively). Insulin dependence did not play a role in progression. Final visual acuity was better in patients without pre-operative DR, as well as in eyes without progressive retinopathy.     

The correction of diplopia after cataract extraction

The records of 12 patients with persistent diplopia after cataract extraction were reviewed. All patients were corrected surgically using an adjustable-suture technique. After strabismus surgery, the diplopia in nine of the 12 patients resolved without adjunctive therapy. Three patients had occasional diplopia postoperatively. Prismatic correction postoperatively was unwarranted in two patients because diplopia occurred on rare occasions, but the third required postsurgical prismatic correction with improvement.     

A systematic overview of the incidence of posterior capsule opacification

OBJECTIVE: Reported rates of posterior capsule opacification (PCO) vary widely and are based on various definitions of PCO, varying lengths and intervals of follow-up, and the use of different surgical techniques, intraocular lens (i.o.l.) designs, and methods of IOL implantation. This study was designed to obtain a more precise overall estimate of the incidence of PCO and to explore factors that might influence the rate of PCO development. DESIGN: A meta-analysis. METHODS: Published articles were selected for study based on a computerized MEDLINE search of the literature and a manual search of the bibliographies of relevant articles. Articles meeting selected inclusion criteria were reviewed systematically, and the reported data were abstracted and synthesized using the statistical techniques of meta-analysis. MAIN OUTCOME MEASURE: Pooled estimates of the proportion of eyes developing PCO at three postoperative timepoints--1 year, 3 years, and 5 years--were measured. RESULTS: There is significant heterogeneity among published rates of PCO. The overall pooled estimates (95% confidence limits) of the incidence of PCO were 11.8% (9.3%-14.3%) at 1 year, 20.7% (16.6%-24.9%) at 3 years, and 28.4% (18.4%-38.4%) at 5 years after surgery. There is no evidence of a significant decline in PCO incidence during the study period. CONCLUSIONS: Visually significant PCO develops in more than 25% of patients undergoing standard extracapsular cataract extraction or phacoemulsification with posterior chamber intraocular lens implantation over the first 5 years after surgery. Patient characteristics, surgical techniques, and differences in research design and reporting may account for some of the variability in reported rates. However, no specific factors were identified in the authors' analysis. More precise estimates of incidence and identification of risk factors for PCO will depend on the development of a standardized measurement of PCO and wider adoption of more rigorous study methodology.     

High-resolution digital retroillumination imaging of the posterior -004 capsule after cataract surgery

PURPOSE: To develop a system for high-resolution imaging of the posterior lens capsule after intraocular lens surgery for objective assessment of posterior capsule opacification (PCO). SETTING: Department of Cataract and Refractive Surgery, St. Thomas' Hospital, London, United Kingdom. METHODS: A system was developed that uses coaxial illumination and imaging based on Zeiss components with a digital camera directly linked to a computer for online image verification and image analysis. RESULTS: The system produced high-resolution digital images with even background illumination of sufficient quality to demonstrate progressive lens epithelial cell changes that are amenable to computer image analysis. CONCLUSION: This system produced excellent images for objective documentation and quantitative measurement of PCO.     

Comparison of methods to assess visual impairment from glare and light scattering with posterior capsule opacification

PURPOSE: To compare 2 glare tests to determine their relative usefulness in the assessment of posterior capsule opacification (PCO) and to evaluate the potential benefits of combined visual, acuity, contrast sensitivity, and glare testing. SETTING: Teaching hospital ophthalmology department. METHODS: Sixteen patients had glare, visual acuity, and contrast sensitivity testing before and after neodymium:YAG (Nd:YAG) capsulotomy. Results with the Brightness Acuity Tester (BAT, Mentor), which measures disability glare, and the Straylightmeter (Foundation for Eye Research, The Netherlands), which quantifies forward scatter by direct compensation techniques, were compared. The correlation between glare, ETDRS visual acuity, and Pelli-Robson contrast sensitivity was determined. RESULTS: Pretreatment visual acuity was significantly correlated with contrast sensitivity (P < .01). However, visual acuity and contrast sensitivity were poorly correlated with both the BAT and Straylightmeter (P > .05), indicating that visual acuity is predictive of contrast sensitivity but a poor predictor of glare. Glare was significantly improved (Straylightmeter, P < .0001; BAT, P < .05) following capsulotomy. While the Straylightmeter consistently measured precapsulotomy forward scatter that improved with treatment, corresponding BAT disability glare was unmeasurable in 18.8% of patients with PCO, as their visual acuities improved rather than deteriorated with glare testing. CONCLUSIONS: Glare testing provided more information than contrast sensitivity when combined with visual acuity in the evaluation of PCO. Glare related to PCO is better assessed using the Straylightmeter because the BAT may yield aberrant disability glare results.     

Results and complications after extracapsular cataract extraction in eyes with pseudoexfoliation syndrome

Postoperative results and complications in 136 eyes with pseudoexfoliation syndrome were compared to 744 eyes without pseudoexfoliation syndrome in a consecutive study. The patients were followed for 4 months postoperatively. Excluding cases with glaucoma, 81.4% of the pseudoexfoliation eyes and 83.0% of the eyes without pseudoexfoliation achieved a corrected visual acuity of 5/8.5 or better. IOL malposition was rare in both groups (1.5% in the pseudoexfoliation group and 1.6% in the group without pseudoexfoliation). IOP elevation the first day postoperatively occurred most often in the pseudoexfoliation eyes. In the pseudoexfoliation eyes, postoperative iritis and cellular precipitates were demonstrated in 16.2% and 11.0%, respectively, compared to 3.8% and 3.2% in the eyes without pseudoexfoliation (p < 0.001). The frequency of an inflammatory reaction was highly correlated to small pupil size during operation in both groups.     

Peroperative microbial contamination of anterior chamber aspirates during extracapsular cataract extraction and phacoemulsification

BACKGROUND: The normal conjunctival flora is one of the main sources of intraocular contamination during cataract surgery. The theory that the positive anterior chamber (AC) pressure during phacoemulsification (phaco), and the smaller wound utilised, might reduce the rate of contamination was studied. METHODS: The peroperative AC aspirates of 210 consecutive patients undergoing cataract surgery were assessed. In group 1, 100 patients underwent a standard extracapsular cataract extraction (ECCE). In group 2, 110 patients underwent phacoemulsification of the crystal-line lens through a scleral tunnel. AC aspirates from the Simcoe irrigation/aspiration cannula (group 1) and phaco probe (group 2) were collected and microbiological studies performed after direct and enrichment cultures. RESULTS: There were 29 (29%) positives in the ECCE group compared with 22 (20%) positive cultures from AC aspirates in the phaco group. Coagulase negative staphylococcus (CNS) was the commonest contaminant in both groups. CONCLUSION: Although there was a higher rate of AC contamination during ECCE, the difference was not statistically significant (p > 0.10, chi 2 = 2.31).     

Decrease of capsular opacification with adjunctive mitomycin C in combined glaucoma and cataract surgery

OBJECTIVE: The authors investigated the incidence of capsular opacification requiring YAG capsulotomy after primary trabeculectomy combined with phacoemulsification and implantation of all polymethylmethacrylate intraocular lenses. DESIGN: A prospective randomized study. PARTICIPANTS: One hundred seventy-four eyes of 174 nonselected patients with primary open-angle glaucoma (POAG) were randomized to either no adjunctive mitomycin C (MMC) control group of 93 eyes of 93 patients) or adjunctive subconjunctival MMC (MMC group of 81 eyes of 81 patients) during the primary glaucoma triple procedure (PGTP). INTERVENTION: Primary glaucoma triple procedure with and without MMC and YAG laser capsulotomy for posterior capsular opacification (PCO) was performed. MAIN OUTCOME MEASURES: The incidences of YAG capsulotomy for PCO were compared between the control and MMC groups and also between the control group and the MMC subgroups (1 minute, 3 minutes, and 5 minutes of MMC application) using Kaplan-Meier analysis with Mantel-Cox log-rank test. Cox proportional hazard regression analysis also was performed to identify significant factors affecting capsular opacification. RESULTS: The control and MMC groups were similar in preoperative characteristics. However, the probability of PCO requiring YAG capsulotomy was significantly lower in the MMC group than in the control group (P = 0.004). Among the MMC subgroups, MMC application for 3 minutes was most effective and significant when compared with that of the control group (P = 0.002). Although not as significant as the intraoperative use of MMC (P = 0.002), old age (P = 0.026) and presence of diabetes mellitus (P = 0.035) were also identified as significant beneficial factors for decreasing the incidence of YAG capsulotomy for PCO in Cox proportional hazard regression analysis. CONCLUSION: Intraoperative subconjunctival MMC application during combined glaucoma and cataract surgery has a beneficial effect of inhibiting PCO after combined surgery in patients with POAG. Thus, after intraoperative subconjunctival application of MMC at the concentration of 0.5 mg/ml for 3 minutes, the aqueous MMC level must have been great enough to inhibit the lens epithelial cell proliferation to result in a long-term decrease in PCO.     

Long-term intraocular pressure control after cataract extraction with trabeculectomy: phacoemulsification versus extracapsular technique

Mutations of the p53 gene are associated with a number of non-lymphoid cancers of the dog. The present study investigates the p53 gene status within canine patients treated for primary and secondary lymphoma. Three out of eight patients exhibited p53 gene mutations. These included one patient with a germ line mutation and two patients with de novo p53 mutations associated with the secondary lymphoma. Allelic loss of the p53 gene was also observed within primary and secondary tumours of the three canine patients. The results indicate that germ line p53 mutations exist in dogs and may be involved in the known predisposition of some breeds to cancer. The presence of therapy-related p53 point mutations was found to be associated with chemoresistant secondary lymphomas. A causative role for DNA-damaging chemotherapy in de novo mutation of the p53 gene is discussed. Characterization of p53 inactivation in canine tumorigenesis may provide a valuable clinical model for assessing the efficacy and optimal therapeutic regimens of anti-cancer agents.     

Corneal endothelium in patients with diabetes after extracapsular cataract extraction with intraocular lens implantation in the posterior chamber

We have examined endothelial cell density before and 3, 6, 12 months after extracapsular cataract extraction with intraocular lens implantation (posterior chamber) in diabetic patients and in non-diabetics. We have not found statistically significant differences between the mean loss of endothelial cells due to surgery in diabetic and non-diabetic patients.