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.     

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.     

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.     

Inhibition of posterior capsule opacification with an immunotoxin specific for lens epithelial cells: 24 month clinical results

PURPOSE: To assess the safety and effectiveness of an immunotoxin, MDX-RA, designed to inhibit posterior capsule opacification (PCO). SETTING: Eleven private practices in the United States. METHODS: This study comprised 63 eyes of 63 patients having extracapsular cataract extraction by phacoemulsification; these patients were enrolled in a Phase I/II clinical investigation of the immunotoxin MDX-RA. At the close of surgery, 21 patients were treated with placebo, 23 patients with 50 units of the immunotoxin, and 19 patients with 175 units of the immunotoxin as an aqueous solution. The patients were monitored for 24 months after primary cataract surgery using external eye and slitlamp examinations, visual acuity assessment, ophthalmoscopy, pachymetry, tonometry, endothelial cell counts, and lens capsule photography. Posterior capsule opacification, recorded on lens capsule photographs, was graded independently by a committee of 3 cataract surgeons. The incidence of neodymium:YAG (Nd:YAG) capsulotomy was projected from the opacification results. RESULTS: The immunotoxin, at the 50 unit dose, was well tolerated and effective in inhibiting PCO. At the 175 unit dose, there was a trend toward increased postoperative inflammation that was transient with no residua. From 6 to 24 months postoperatively, the 50 unit dose significantly inhibited PCO compared with the placebo (P < .05). This significant reduction in PCO translated into a significantly lower projected need for Nd:YAG capsulotomy in the 50 unit than the placebo group (P < .004). About 60% in the placebo group and 4% in the 50 unit group were projected to need an Nd:YAG capsulotomy by 3 years postoperatively. CONCLUSION: The immunotoxin was well tolerated and was effective in reducing PCO for up to 24 months after cataract surgery. Although these preliminary results are encouraging, a larger study is underway to determine whether the reduction in PCO by the immunotoxin decreases the need for Nd:YAG capsulotomy.     

Comparison of methods to assess coronary heart disease prevalence in South Asians

BACKGROUND: Migrants from the Indian subcontinent (South Asian migrants) in the United Kingdom have high mortality from coronary heart disease (CHD) in comparison to the indigenous population. Few studies have assessed the prevalence of CHD in South Asians, and the applicability of conventional survey methods in this population is not known. In this pilot random population survey of South Asian men and women living in West London, the prevalence of CHD as judged by the Rose questionnaire, past cardiac history, cardiologist and resting electrocardiogram were compared. METHODS: Subjects aged 30-64 years from randomly selected households were invited for a cardiological assessment. A lay person administered the Rose questionnaire and recorded the past cardiac history. A cardiologist also made an independent assessment and a 12-lead electrocardiogram was recorded and analysed according to the Minnesota code. RESULTS: Three hundred and seventy-six individuals (192 men and 184 women) were assessed. The prevalence of angina in men and women, respectively, was 3.1% and 4.9% by the Rose questionnaire; 2.6% and 2.2% by past cardiac history; and 4.2% and 0.5% according to the cardiologist. The prevalence of myocardial infarction in men and women, respectively, was 5.2% and 2.2% by the Rose questionnaire, 3.6% and zero by past cardiac history and 3.6% and 0.5% by the cardiologist. Q/QS codes were present in 1.6% men and 0.5% women and ischaemic codes in 13% men and 14% women. Ischaemic changes were not associated with any cardiac history in 72% of men and 92% of women. For a diagnosis of CHD in men, there was poor agreement between the Rose questionnaire and either the past cardiac history or the cardiologist's assessment, but moderate agreement between the past cardiac history and the cardiologist. Agreement was poor between all three methods for a positive diagnosis of CHD in women. CONCLUSION: Current accepted epidemiological methods for assessing CHD prevalence may be inaccurate in South Asians, especially women. Electrocardiogram abnormalities suggestive of ischaemia are common in South Asians and are usually not associated with evidence of CHD. Thus, their value as indicators of CHD is questionable.     

Inhibition of posterior capsule opacification by an intraocular-lens-bound sustained drug delivery system: an experimental animal study and literature review

PURPOSE: To find a way to prevent or significantly reduce posterior capsule opacification (PCO) with modern phacoemulsification and in-the-bag intraocular lens (IOL) implantation. SETTING: Department of Ophthalmology and Institute for Pharmaceutical Technology and Biopharmacy, Ruprecht-Karls-University of Heidelberg, Germany. METHODS: We evaluated the effects of an IOL-bound sustained drug delivery system (SDDS) consisting of the carrier substance poly-DL-lactid and the drug daunorubicin or indomethacin. The system was applied to the IOL surface and implanted in rabbit eyes. At 8 weeks postoperatively, PCO wet mass was determined. Toxic and inflammatory effects were documented by histopathology. RESULTS: The average PCO wet mass was 54.6 mg in the control group, 28.6 mg with daunorubicin, and 64.1 mg with indomethacin. Statistical analysis showed a significant reduction of PCO with daunorubicin (Mann-Whitney U-test, P = .025) and no PCO-reducing effect with indomethacin. Light microscopy of the specimens revealed mild inflammation, especially at the limbus, and some endothelial cell loss in the daunorubicin group and iris and ciliary body inflammation in the indomethacin group. CONCLUSION: In the rabbit eye, slow release of daunorubicin reduced PCO formation by approximately 50%. It must be determined whether the endothelial side effects are specific to the rabbit species or whether the human cornea is as sensitive. The principle of the IOL-bound SDDS and the evaluation procedure can be standardized and used for systematic tests in the future.     

Platelet aggregation in acute coronary syndromes: use of a new aggregometer with laser light scattering to assess platelet aggregability

PURPOSE: To describe the computed tomographic (CT) appearance of hepatic infarcts resulting from arterial insufficiency in native livers. MATERIALS AND METHODS: The authors retrospectively reviewed the clinical and imaging findings in 10 patients (five men, five women; age range, 28-70 years) with 14 hepatic infarcts seen over 3 years. CT scans were analyzed for infarct appearance, vessel patency, and evolution of infarct pattern over time. RESULTS: Hepatic infarction resulted from hepatobiliary surgery (n = 6), radiologic intervention (n = 3), and celiac occlusion secondary to antiphospholipid syndrome (n = 1). All 14 infarcts were of low attenuation, peripheral, and wedge-shaped. Occluded arterial vessels were identified in eight patients. Follow-up CT revealed infarct diminution with parenchymal atrophy and scarring (n = 5), progressive liquefaction (n = 2), or both parenchymal atrophy and progressive liquefaction (n = 1). CONCLUSION: Sudden interruption of hepatic arterial flow may cause acute native liver infarction. Patients at risk include those with underlying vascular disease who undergo complicated surgical procedures and those undergoing peripheral arterial embolization.     

Intraoperative miotics and posterior capsular opacification following phacoemulsification with intraocular lens insertion

BACKGROUND AND OBJECTIVES: Posterior capsular opacification (PCO) is a frequent complication following phacoemulsification with intraocular lens (IOL) implantation. A series of consecutive patients receiving capsular bag-fixated, silicone IOL implants were assessed for both incidence of PCO and the administration of intraoperative miotics. PATIENTS AND METHODS: During a 5-year period, 477 consecutive eyes were retrospectively evaluated. Surgeries were grouped according to intraoperative miotic agent: 0.01% carbachol or 1.0% acetylcholine. Patients receiving no miotic drug served as a control group. Yttrium-aluminum-garnet (YAG) laser posterior capsulotomy was performed on patients with clinically significant PCO. RESULTS: The percentage of eyes requiring YAG laser capsulotomy was similar for the three groups: 21.6% (25 of 91) for the carbachol group, 18.4% (14 of 62) for the acetylcholine group, and 18.6% (53 of 232) for the control group. A chi-squared analysis indicated that the difference among the groups was not statistically significant. The three groups also had similar average follow-up times between surgery and YAG capsulotomy (carbachol group = 52.2 weeks, acetylcholine group = 47.5 weeks, and control group = 48.3 weeks). CONCLUSION: Intraocular miotics do not increase the incidence of PCO.     

Cell biological analysis with respect to cause of fibrous opacification of the anterior capsule after cataract extraction

To assess whether juvenile-onset epilepsy or motor disability is complicated by an increased number of mental health disorders or experience of psychosomatic symptoms in young adulthood, we studied 81 subjects with epilepsy and 52 with motor disabilities at the age of 19 to 25 years and compared them with 211 controls. The main diagnostic tool, the Present State Examination, was administered to those attending the interviews in person who were of normal intelligence; there were 62, 38, and 123 subjects in the three categories, respectively. Compared with the controls, the subjects with epilepsy showed an equal prevalence of psychiatric disorders whereas those with motor disabilities had a significantly higher prevalence, particularly of depressive disorders. The reported prevalence of psychosomatic symptoms confirmed this main result. Psychological illness affected everyday life of two out of five subjects with motor disabilities, but only half of those in the other two groups. It is concluded that motor disability since childhood, but not epilepsy, could be a factor that increases susceptibility to psychiatric morbidity, especially depression, and causes a large number of psychosomatic symptoms. The results challenge staff of clinics working with such adolescents to find individual approaches in preventing the negative influence of psychological disorders on social life.     

Six methods to assess potential radioactive air emissions from a stack

1. The individual long-term effects of the antidepressant drugs zimeldine, viloxazine, imipramine, amitriptyline, nortriptyline, maprotiline, or nomifensine, on brain mitochondrial monoamine oxidase (MAO) activity, were studied in mice that were given daily intraperitoneal injections (30 mg/kg) of these reagents for 4 weeks. 2. Both the A-form (MAO-A) and B-form (MAO-B) of MAO were inhibited after long-term administration of all the drugs except nortriptyline (MAO-A was not affected) and maprotiline (neither MAO-A nor MAO-B were affected). 3. Kinetic analysis showed a significant decrease in Vmax values, and an increase in K(m) values for MAO-B during treatment. 4. All seven drugs are competitive inhibitors of MAO-A, noncompetitive inhibitors of MAO-B, and were more potent in vitro for MAO-B. 5. MAO-A was inhibited by the following drugs (in ascending order of potency) : nortriptyline, amitriptyline, imipramine, maprotiline, zimeldine, nomifensine, and viloxazine. 6. MAO-B was inhibited by the following drugs (in ascending order of potency): nortriptyline, imipramine, maprotiline, amitriptyline, zimeldine, nomifensine, and viloxazine.     

Empirically based methods to assess the preferences of individuals with severe disabilities

A literature review was conducted to provide a synthesis of 18 years of research on preference assessment with individuals who have severe disabilities (e.g., severe mental retardation, autism, multiple disabilities). Through this synthesis, several procedural variables were identified that may influence the outcome of preference assessment, including context, assessment stimuli, selection response, and format. Recommendations were given for designing preference assessment, and questions were raised for future research.     

Perceived overprotection and distress in adults with visual impairment.

Objective: To investigate the role of perceived overprotection, a problematic aspect of social support, as a risk factor for distress among adults with chronic vision impairment. Study Design: Cross-sectional study using telephone interviews. Setting: Vision rehabilitation agency. Participants: One hundred fourteen adults with vision impairment (ages 24-64). Measures: 18-item Overprotection Scale for Adults, 20-item Center for Epidemiological Studies-Depression Scale, 21-item Beck Anxiety Inventory. Results: Hierarchical multiple regression analyses demonstrated that higher levels of perceived overprotection were associated with higher levels of depressive symptomatology as well as higher levels of anxiety. Conclusions: Vision rehabilitation programs should address issues around perceived overprotection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Crystallins from rat lens are especially susceptible to calpain-induced light scattering compared to other species

PURPOSE: To compare the susceptibility of crystallins from various animal species to formation of light scattering elements after proteolysis by calpain II enzyme (EC 3.4.22.17). METHODS: Lens, total soluble proteins from: 12-day and 4-week old rat, fetal and adult bovine, 16-day embryonic and 10-week chicken, and young human cortex and nucleus were proteolyzed by either endogenous lens calpain or addition of purified calpain II for 24 h followed by incubation for up to 11 days. Absorbance of light at 405 nm estimated light scattering by crystallins; SDS-PAGE and 2D-electrophoresis assessed proteolysis on the crystallins. RESULTS: Most rapid light scattering occurred with total soluble proteins from young rat lens, either after adding purified calpain or by activating endogenous lens calpain with calcium. (Only rat lens showed activation of endogenous calpain II.) beta-crystallin polypeptides from rat, bovine, human, and to a more limited extent, chick lens were partially proteolyzed by addition of purified calpain II. In spite of this proteolysis, total soluble proteins from chicken, bovine, and human lenses showed no obvious light scattering by action of calpain. Crystallins from older rat lens showed approximately 50% of the light scattering displayed by crystallins from younger rats after 3 days, but only when purified calpain was added. CONCLUSIONS: Our results indicate an unusually high susceptibility of crystallin polypeptides from young rat lens to formation of light scattering elements after limited proteolysis. Thus, young rat lens provides a unique opportunity to investigate how properties of crystallins influence the development of light scattering found in cataract.