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A rotating random-phase-screen diffuser is sometimes employed on synchrotron x-ray imaging beamlines to ameliorate field-of-view inhomogeneities due to electron-beam instabilities and beamline optics phase artifacts. The ideal result is a broader, more uniformly illuminated beam intensity for cleaner coherent x-ray images. The spinning diffuser may be modeled as an ensemble of transversely random thin phase screens, with the resulting set of intensity maps over the detector plane being incoherently averaged over the ensemble. Whilst the coherence width associated with the source is unaffected by the diffuser, the magnitude of the complex degree of second-order coherence may be significantly reduced [K. S. Morgan, S. C. Irvine, Y. Suzuki, K. Uesugi, A. Takeuchi, D. M. Paganin, and K. K. W. Siu, Opt. Commun. 283, 216 (2010)]. Through use of a computational model and experimental data obtained on x-ray beamline BL20XU at SPring-8, Japan, we investigate the effects of such a diffuser on the quality of Fresnel diffraction fringes in propagation-based x-ray phase contrast imaging. We show that careful choice of diffuser characteristics such as thickness and fiber size, together with appropriate placement of the diffuser, can result in the ideal scenario of negligible reduction in fringe contrast whilst the desired diffusing properties are retained.

We seek to establish non-invasive imaging able to detect and measure aspects of the biology and physiology of surface fluids present on airways, in order to develop novel outcome measures able to validate the success of proposed genetic or pharmaceutical therapies for cystic fibrosis (CF) airway disease. Reduction of the thin airway surface liquid (ASL) is thought to be a central pathophysiological process in CF, causing reduced mucociliary clearance that supports ongoing infection and destruction of lung and airways. Current outcome measures in animal models, or humans, are insensitive to the small changes in ASL depth that ought to accompany successful airway therapies. Using phase contrast X-ray imaging (PCXI), we have directly examined the airway surfaces in the nasal airways and tracheas of anaesthetised mice, currently to a resolution of approximately 2 microm. We have also achieved high resolution three-dimensional (3D) imaging of the small airways in mice using phase-contrast enhanced computed tomography (PC-CT) to elucidate the structure-function relationships produced by airway disease. As the resolution of these techniques improves they may permit non-invasive monitoring of changes in ASL depth with therapeutic intervention, and the use of 3D airway and imaging in monitoring of lung health and disease. Phase contrast imaging of airway surfaces has promise for diagnostic and monitoring options in animal models of CF, and the potential for future human airway imaging methodologies is also apparent.

Purpose: To determine the utility of mass photoscreening for detecting visual anomalies in young, school-age children., Setting: Seventy elementary schools in Alabama, Florida, Georgia, North Carolina, and Virginia, USA., Methods: An off-axis photorefractive technique was used to screen 14,591 children in kindergarten, first, and fourth grades in 70 schools in 5 southeastern states in the United States., Results: A total of 14,075 (96.5%) of the screenings yielded analyzable photographs. Overall, 647 (4.6%) children had significant ocular findings; significant was defined as hyperopia 2.50 diopters (D) or more, myopia 1.00 D or more, anisometropia 1.00 D or more, astigmatism 2.00 D or more, media opacity 1.0 mm or more in diameter, or 5 degrees or more or 10.00 prism diopters or more of ocular misalignment. Another 950 (6.7%) had possibly significant findings, defined as the sign being present but in an amount less than that considered significant. The most common refractive error was myopia (4.5%), followed by anisometropia (3.1%), hyperopia (2.9%), and astigmatism (1.0%). Alignment problems were found in 1.7% and media opacities in 0.1%. Among the 1.0% with other ocular anomalies were cases of anisocoria greater than 2.0 mm or irregular pupils, ptosis greater than 2.0 mm, and subconjunctival hemorrhages. In all, 202 children had significant anomalies thought to predispose to amblyopia, including 196 with significant anisometropia and 6 with significant lens opacities. At a screening cost of $5 per child for the whole study, the cost of identifying these children with potentially blinding eye disease was $361 each., Conclusion: Mass photoscreening may be used to detect amblyogenic conditions in children early enough to prevent blindness with timely and appropriate treatment.

Cataracts in children present a greater management challenge, compared with cataracts in adults, because of the wider variety of causes and the vulnerability of the developing visual system. The fundamental principles--early diagnosis and treatment for visually significant cataracts--have not changed. Amblyopia remains a major problem in children with unilateral and asymmetrical cataracts. The use of vitrectomy instrumentation in the removal of infantile cataracts has become relatively standard; however, the tendency now is to leave a rim of posterior capsule sufficient to allow secondary placement of a posterior chamber intraocular lens at a later date. Intraocular lens implantation is being aggressively pursued in children and, with modern microsurgical techniques, may be desirable in children as young as 2 years of age or younger in special circumstances. Contact lenses continue to be ideal for the infant and growing child to provide flexibility as the refraction changes.

A 60-year-old Native American diabetic female patient had a history of nine episodes of peritonitis (both relapsing and persistent) during the year that she was treated with continuous ambulatory peritoneal dialysis (CAPD). At the start of CAPD the patient had an inverted CD4 to CD8 ratio that decreased from 0.97 to 0.50 in 1 year. This finding was due to a decrease in CD4+ cells and an increase in CD8+ cells that were also positive for CD57 (Leu-7) and HLA-DR (Ia) antigen, suggesting a state of activation. The serology indicated a cytomegalovirus immunoglobulin G titer of 1:2,048. The patient also had significantly increased natural killer cells. These alterations suggest the presence of a chronic viral infection that may have caused the patient to be immunosuppressed, thereby predisposing her to repeated episodes of peritonitis.

Traditional methods of visual assessment in preverbal pediatric patients rely on refined but subjective measurement techniques. A standard ophthalmologic examination includes evaluation of a child's fixation patterns, with performance ranked on the basis of ability to fix and follow an object (F & F) or maintain central, steady fixation (CSM). In the hands of a skilled clinician, these evaluations are important for diagnosis and treatment. Documentation of quantitative changes in visual abilities of preverbal patients, however, has only recently become feasible. We began using the acuity card procedure in our pediatric clinical practice more than 3 years ago. This assessment, a modified version of the standard Forced-Choice Preferential Looking paradigm (FPL), provides quantitative evaluation of visual functioning in preverbal patients. The total number of patients assessed on one or more occasions exceeds 900. Of this group, we followed 83 patients with at least four acuity card evaluations on separate visits. Thirty of these patients, all with different diseases, have been evaluated with acuity cards on six or more visits. We found the information provided by the acuity card assessments extremely helpful in quantifying the developmental and therapeutic changes in vision, previously monitored only qualitatively.

Corneal curvature was evaluated in 70 children by central keratometric measurements. The mean keratometric reading in each age group was seen to decline systematically from birth to about 54 months of age. The mean in the newborn-to-6-month-old group was 47.59 D; in the 12-18-month-old group it had decreased to 45.56 D. The cornea appears to stabilize at about 54 months, with an average reading of 42.69 D. Evaluation of 11 eyes diagnosed as having persistent hyperplastic primary vitreous revealed that eyes with this diagnosis generally have steeper corneas than normal eyes at any given age.

The survival rate of children with localized orbital rhabdomyosarcoma is now greater than 90% 3 years after diagnosis as a result of advances in radiation and chemotherapy. Ninety percent of these children develop cataracts within 1 to 4 years after the completion of radiotherapy. The correction of aphakia in these children is complicated by the concurrent keratoconjunctivitis and dryness associated with radiotherapy. Three patients with a diagnosis of orbital rhabdomyosarcoma underwent treatment for uniocular cataract. Two of the patients were unable to use extended wear contact lenses. Both underwent epikeratophakia with poor results. One patient who had clinically significant ocular drying prior to cataract extraction underwent successful implantation of an intraocular lens as a primary procedure, with excellent visual results. Clinicians should be aware of the difficulties associated with contact lens wear and epikeratophakia tissue lenses in children who have had high doses of radiation for orbital rhabdomyosarcoma. Such patients are probably best served by primary intraocular lens implantation or by preservation of the posterior capsule at the time of cataract extraction to allow secondary lens implantation if contact lens wear is unsuccessful.

Acyclovir [9-(2-hydroxyethoxymethyl)guanine] is a new antiviral agent which has specific activity in virus-infected cells. The drug has a high therapeutic index in animal and laboratory models but had not been tested for toxicity in human eyes at the time of this study. A randomized double-blind study on patients requiring antiviral therapy for treatment or prophylaxis of herpetic ocular infections revealed minimal irritation associated with topical administration. Further controlled studies will be necessary to evaluate this compound's clinical efficacy.

The study of occlusion amblyopia and its therapy has involved animal models of stimulus deprivation achieved by various means, none of which closely simulates human congenital cataract. The authors used the Nd-YAG laser as a means of inducing cataracts in rabbit eyes. Twenty rabbit eyes were treated at various frequency and power settings. High energy YAG laser pulses of 10 mJ produced cataracts that at first resembled large bubbles. Over several days, these bubbles coalesced into smaller opacities. With multiple treatments (usually 150-200 pulses), the authors could create a cataract of a specific size and position. Six months later, 100% of these laser-treated rabbit eyes showed persistent cataracts that resembled human congenital cataracts. It appears that the YAG laser can provide a reproducible and reliable method of inducing specific types of cataracts in animal eyes without damaging other ocular structures.

We have identified an activity which alters the morphology and developmental timing of post-compaction mouse embryos. A 15-min exposure of 4- and 8-cell mouse embryos to sera containing this activity induced monolayer formation, changing the normal positions of blastomeres at the 16- to 64-cell stages. Recovered embryos form normal blastocysts, based on morphology and in vitro production of trophectoderm and inner cell mass derivatives. These results suggest that under certain circumstances blastomeres remain developmentally labile as late as the sixth or seventh cleavage cycle.

Five patients required secondary surgical procedures after receiving epikeratophakia grafts. A neonate underwent epikeratophakia in combination with extracapsular cataract extraction, followed one week later by peripheral iridectomy and nine months later by strabismus surgery. A 53-year-old male had surgery to correct retinal detachment 4-1/2 months after epikeratophakia surgery for the correction of aphakia. A five-year-old male had epikeratophakia after removal of a traumatic cataract; five weeks later, retinal detachment necessitated vitrectomy, 360 degrees buckle, and cyclocryotherapy. A 4-1/2-year-old female had epikeratophakia for aphakia, followed nine months later by strabismus surgery. A 38-year-old female with keratoconus received a plano epikeratophakia graft, in combination with an extracapsular cataract extraction and anterior vitrectomy, followed two weeks later by an Ocutome vitrectomy. In all cases, the epikeratophakia grafts and interfaces remained clear, and in four of the five patients in whom secondary procedures were successful, vision continued to improve with time.

In the nationwide study of epikeratophakia, 154 ophthalmic surgeons who had attended a training course performed 519 procedures for the correction of aphakia in adults: 310 of the eyes had 30 or more days of follow-up after suture removal. Of 229 eyes, 172 (75%) were within 3 diopters of emmetropia after surgery. Of 259 eyes, 245 (95%) demonstrated improved uncorrected visual acuity; 138 (53%) improved by four or more Snellen lines. Of 265 eyes, 209 (78%) achieved within two lines or improved their best corrected visual acuity. Of the 119 patients who achieved or improved their preoperative best corrected visual acuity, 110 (92%) were within two Snellen lines or better by 30 to 60 days after suture removal. Of the 127 patients with more than three months of follow-up after suture removal, 124 (98%) of those between 18 and 70 years of age but only 13 of 23 (54%) of those between 81 and 87 years of age achieved within two lines or better of their best corrected visual acuity. Corneal astigmatism measured by keratometry changed from a preoperative mean (+/- S.D.) of 2.1 +/- 1.8 diopters to a postoperative mean of 2.7 +/- 2.6 diopters. Of the 519 tissue lenses, 22 (4%) were removed, and one third of these patients underwent a second, successful epikeratophakia procedure.

Epikeratophakia provides a permanent optical correction for aphakia in children with congenital or traumatic cataracts; suturing the epikeratophakia graft onto the cornea eliminates the problems of contact lens or spectacle non-compliance in these young and generally uncooperative patients and provides tectonic support to scarred and irregular corneas. Eighteen children under the age of six years underwent epikeratophakia for the correction of aphakia after the removal of trauma-induced cataracts. Graft success rate was 88%; the average change in keratometry in the patients with successful grafts was 14.82 +/- 2.0 diopters. In the 13 patients eligible for visual acuity tabulation, preoperative acuities ranged from light perception to 20/200, and postoperative acuities ranged from hand motions to 20/30. Ten (77%) had acuities of 20/80 or better. Poor results in three patients with less than 20/200 acuities were likely the results of non-compliance with amblyopia therapy. Present work indicates that in cases of traumatic cataract, the epikeratophakia procedure facilitates amblyopia therapy and decreases the astigmatism in scarred and irregular corneas.

Seven Shearing lenses were inserted in four dogs that were selected because their ciliary body sulcus diameter was approximately equal to that of humans. These animals were killed at intervals ranging from 4.5 to 11 months and the eyes submitted for histopathology. In all instances, gross examination revealed the lenses to be well tolerated; however in two eyes there was migration of the peripheral loop into the peripheral iris stroma and in one case, ciliary body sulcus necrosis was seen. No vitreous hemorrhage was found in any of the eyes. One intraocular lens was removed before the animal was killed and the eye did not appear to be damaged. This study raises the possibility of ciliary body damage in those eyes in which the lens is slightly displaced so that one loop exerts pressure on the ciliary body. For this reason, we feel that posterior vitreous hemorrhages must be carefully looked for.