Infiltrative keratitis with contact lens wear--a review

BACKGROUND: "Infiltrates" of white blood cells aggregating in the superficial cornea are common with corneal inflammation. The etiologies of such inflammation vary widely and include an association with contact lens wear. METHODS: This paper reviews the literature regarding corneal infiltrative keratitis with contact lens wear. Basic mechanisms in the development of corneal infiltrates as well as etiologies are presented. Associations and causes, clinical presentation, differential diagnosis, course, and treatment for corneal infiltrates in contact lens wearers are reviewed. CONCLUSIONS: Corneal infiltrates associated with contact lens wear may stem from a variety of causes including factors related to the lens material, design, condition; the lens wearing schedule; environmental factors such as external environment; and lens care patterns, procedures, and products. Individuals who wear contact lenses are also subject to the many non-contact lens-related stimuli to corneal infiltration. Accurate diagnosis and appropriate management of corneal infiltrates with contact lens wear is important, especially due to the possibility of infectious etiology.     

Gene organization, primary structure and RNA processing analysis of a ribosomal RNA operon in Lactococcus lactis

The introduction and development of soft lenses and rigid gas-permeable lenses has ushered in a new era in fitting athletes with contact lenses. Many of the well-known disadvantages associated with polymethylmethacrylate (PMMA)-type lenses have been either eliminated or minimized. Fitting athletes with contact lenses must still be viewed with caution, however, since athletes' visual needs are usually much more demanding than those of the general public. An indiscriminate choice of lens design can adversely affect athletic performance and may even create a hazardous situation. An intelligent choice of lens can provide some subtle advantages that may improve athletic performance and provide the margin for victory.     

Gonorrhoea in Coventry 1991-1994: epidemiology, coinfection and evaluation of partner notification in the STD clinic

BACKGROUND: Contact lens wearers are subject to increased risk of infection, and an attempt was made to determine which factors cause the overproportional risk of infection? PATIENTS: The aim of this paper is to explain with appropriate bibliographic support why people who wear contact lenses are at risk of infection. RESULTS: The relative risk of keratitis is a function of the lens material and the wearing time of the contact lenses. Extended wear of hydrogel lenses is associated with an overproportional risk of infection. According to the literature, the frequency of complications in contact lens wearers generally is the result of poor hygiene in 66% of the cases. The general lack of hygiene among contact lens wearers must, therefore, be regarded as one cause among pathophysiological mechanisms of the eye. The microbial spectrum favors gram-negative bacteria living in a wet environment such as Pseudomonas, Serratia and parasites like Acanthamoeba. CONCLUSION: The specific spectrum of pathogens and new problem organisms not only challenge the fitter but also the manufacturers to adapt hygiene (sanitary) measures and products to the new development. Disposable contact lens systems are the first step, but they do not solve all the problems of contact lens wearers. Therefore, the importance of contact lens hygiene must be especially emphasized when the ophthalmologist is giving instructions to the patient. On the other hand, hygiene should also not be neglected by the contact lens fitters since it is part of the whole problem.     

Clinical evaluation of Acuvue contact lenses with UV blocking characteristics

BACKGROUND: In response to increasing scientific evidence which indicates that ultraviolet radiation (UVR) is a potential threat to ocular health, Acuvue contact lenses (Vistakon, Johnson & Johnson Vision Products Inc., Jacksonville, Florida) have been developed which incorporate an ultraviolet (UV) blocker within the lens polymer. Data are presented for the first clinical evaluation of Acuvue lenses with UV blocking characteristics. METHOD: A double-masked, multicenter, prospective clinical trial involving 94 subjects was conducted. The study followed a randomized, parallel group design and consisted of 3 months of daily wear with two-weekly lens replacement. Two thirds of the subjects (61) wore the test lenses (Acuvue with UV blocker) and the remaining subjects (33) wore conventional Acuvue lenses (without UV blocker). RESULTS: Biomicroscopic evaluations indicated that the performance of the test and control lenses was clinically similar. No clinically relevant differences between the test and control lenses were noted in the subjective assessments of vision, comfort, or handling. In addition, no differences were shown for surface deposition, lens durability, visual acuity, and subjective symptoms. CONCLUSION: The study findings indicate that the addition of a UV blocker to Acuvue contact lenses has been achieved without affecting daily wear clinical performance. Because there is increasing evidence to suggest that the ocular tissues may be damaged by UVR, it is prudent for eye care practitioners to prescribe contact lenses that offer the benefits of both regular replacement and UV protection.     

Evolution of C4 photosynthesis in response to changes in carbon and oxygen concentrations in the atmosphere through time

This work is a survey of 82 cases of keratoconus which have been followed up for 1 to 12 years. Among them only 66 were fitted with contact lenses. The contra-indications for them are: 1. a better visual acuity with spectacles than with contact lenses, 2. advanced cases (4th degree of Amsler) whose fitting is impossible, 3. unilateral keratoconus, 4. associated diseases such as trachomatous pannus, allergic kerato-conjunctivitis. Hard corneal lenses are now in use in most of the cases. Scleral lenses are much less used than they were 10 years ago, owing probably to the great improvement of the corneal lenses during this time. These hard corneal lenses have a short Ro (4 to 7 mm), an overall diameter between 8 and 11 mm, and an optic diameter of 5 mm. They are fitted under fluorescein control. The mobility must be good too. One case was fitted with soft lenses. The visual acuity is good and so is the tolerance: 80% of the patients wear their lenses 10 hours a day or more. Contact lenses do not affect the progression of keratoconus thus finally a keratoplasty must be performed in many cases. After the operation a contact lens is very often necessary, but its daily wearing time must be divided by two, to avoid corneal neo-vascularisation. Soft corneal lenses may be used in some cases of keratoconus. They are indicated when the hard lenses are no longer tolerated and before a keratoplasty. The base curves of these soft lenses are not related to the radii of the conic cornea. In most of the cases they are between 7.50 and 8.60 mm. The diameter is large: 14 or 15 mm. The lenses must not move too much: 1 mm up or down when the patient blinks. The edge of the lens must not depress the bulbar conjunctiva and there must be no air bubble under the lens. In many cases a cylindrical spectacle lens is necessary to obtain a good visual acuity. Some authors prefer to fit a hard corneal lens over the soft one: this is the "piggy back" method. Sometimes keratoconus has appeared in patients already fitted during several years to correct a myopic astigmatism. It is not clear whether these keratoconus have been produced or not be the contact lenses.     

Superposition of sphero-cylindrical lenses using contour graphs

BACKGROUND: The superposition of thin sphero-cylindrical lenses with arbitrary angles between cylindrical axes is sometimes required in a clinical setting. For example, it may be useful in some instances to perform an overrefraction which, added to the spectacle or toric contact lens in place on the eye, yields a final correcting lens. METHODS: Computer calculations have been used to create contour graphs allowing a graphical solution to the problem of combining sphero-cylindrical lenses. Although conceptually strightforward, the method has not been presented before. RESULTS: The use of contour graphs to superpose sphero-cylindrical lenses is shown by examples to be accurate and much simpler than calculational methods. CONCLUSIONS: Lacking a pre-programmed computer, the method of contour graphs offers a practical method of combining sphero-cylindrical lenses.     

Prepare to negotiate your next employment agreement

PURPOSE: The purpose of this study was to evaluate the outcome of patients with healed moderate to severe contact lens-associated corneal infectious ulcers who were re-fit with contact lenses. METHODS: We retrospectively studied patients who were fit with contact lenses on our service and who had had moderate to severe corneal infectious ulcers associated with previous contact lens use. Six patients were included in the study. RESULTS: Gas permeable contact lenses were fit in five patients, and a soft contact lens was fit in one patient. Successful fit was achieved in all cases and visual acuities were equal to or better than 20/30 in all patients. No significant complications were observed after a mean follow-up of 23 months (range, 6-45 months). CONCLUSION: In this small series of patients with a history of moderate to severe contact-lens related infectious keratitis, no complications were observed after contact lenses were refit. Contact lens wear in patients with a history of infectious keratitis may be safe and useful in order to achieve visual rehabilitation.     

Enhanced hepatotoxicity of acetaminophen in the alcoholic patient. Two case reports and a review of the literature

PURPOSE: Bacterial adherence or binding to the target cell is a prerequisite for the initial stage of most infections and seems to be mediated by lectin-like ligands on the bacterial surface and specific receptors on the target cell membrane. The purpose of this study was to establish whether contact lens wear under closed eye conditions changes the glycocalyx layer, whether it exposes more lectin receptors than eye closure without a contact lens, and whether wear of low oxygen transmissibility (Dk/L) contact lenses exposes more receptors than high Dk/L contact lenses. METHODS: The eyes of six rabbits under general anesthesia were fit with either a high Dk/L soft contact lens (40 x 10(-9), boundary corrected) or a low Dk/L soft contact lens (2 x 10[-9]) or were left without a lens as controls. All eyes were kept closed by suturing for 24 hours. After removal of the contact lenses, all corneas were excised, put in glutaraldehydeforfixation, rinsed, incubated with plant-derived lectins (wheat-germ agglutinin [WGA]) conjugated with gold particles, and prepared for electron microscopy. Membrane associated gold particles were counted and the results were processed statistically. RESULTS: After 24 hours of lens wear under closed eye conditions, the glycocalyx layer showed physical changes in the form of thinning or compression and signs of biochemical changes reflected as an increase in number of WGA receptors. The average number of membrane associated gold particles per 750 micro length of corneal epithelium in control corneas was 1,287.5 +/- 92.5. Particles were significantly (P<0.001) more numerous after wear of high Dk/L contact lenses (3,230.0 +/- 294.5) and after wear of low Dk/L contact lenses (4,611.3 +/- 223.3). The figure after wear of low Dk/L contact lenses was significantly (P<0.01) higher than the figure after wear of high Dk/L contact lenses. CONCLUSION: Our results indicate that lens wear under closed eye conditions seems to change the corneal glycocalyx layer physically as well as biochemically. Significantly larger numbers of WGA receptors were exposed after contact lens wear than without a contact lens. Significantly more receptors were exposed after wear of low Dk/L contact lenses than after wear of high Dk/L contact lenses. These changes may be of importance in relation to the risk of bacterial keratitis.     

The Support Network: Crisis intervention for extrafamilial child sexual abuse.

Describes the establishment of the Support Network, a community-based treatment program for children and families facing crises due to extrafamilial child sexual abuse. The components necessary to establish a Support Network are discussed. A crisis intervention model of treatment is proposed that provides these children and families with immediate contact with a therapist, emotional support, education, and problem-solving strategies, thus enabling some resolution of the crisis and a return to precrisis routines and adaptation. Termination and follow-up issues are also addressed, and a case example of 4-yr-old sexually abused girl is presented to illustrate the usefulness of the Support Network. It is contended that, by providing services to these children and their families, Support Network therapists also help to sensitize and educate other community professionals to the needs of the sexually abused child and his/her family. A list of selected references for use with children and families is appended. (48 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contact lenses. 2: Contact lens associated infections

Contact lens wearers, especially those who wear soft or extended wear contact lenses, are at increased risk of suffering from keratitis. Among the causes of corneal infections, an inadequate hygiene or overextended wear play an important role. An insufficient cleaning and disinfection leads to contamination with pathological germs. Sites of entry for these germs are corneal microlesions, caused by the setting and removal of contact lenses, and epithelial defects, as a result of the wearing of old or defective contact lenses. Primary eye diseases of patients who wear contact lenses can be altered by their wearing, and vice-versa. Even more, miscellaneous infections may lead to infectious corneal ulcerations. Having an adequate hygiene, a proper patient orientation during the medical visit, and a regular control are therefore of great importance for the reduction in the frequency of such infections by patients who wear contact lenses.     

Secondary intraocular lens implantation after cataract surgery in children

PURPOSE: To report results of secondary intraocular lens implantation after cataract surgery in children. METHODS: We reviewed clinical records for a 5-year period of patients who had cataract surgery in childhood and received a secondary intraocular lens implant. We studied indications for secondary intraocular lens placement; surgical procedures for intraocular lens implantation; preoperative and postoperative visual acuity, refractive error, and binocular status; and complications of the procedure. RESULTS: A secondary intraocular lens was placed in 28 eyes of 25 patients who had cataract surgery in childhood. In 20 eyes, the lenses were placed in the ciliary sulcus. The other eight eyes had insufficient capsular support for an intraocular lens; in two, the intraocular lens was placed in the anterior chamber and, in six, in the posterior chamber with suture fixation to the sclera. Twenty of 28 eyes (71%) had measurable improvement in visual acuity; only one eye had a decrease in visual acuity of 2 lines. Fifteen patients (54%) had a final refraction within 1.50 diopters of the fellow eye; 21 (75%) were within 3.00 diopters. During follow-up, two eyes developed glaucoma. One had transient pressure elevation; one required two filtration procedures. Three patients required Nd:YAG capsulotomy. Six patients demonstrated Worth fusion at distance and near; three demonstrated 200 seconds of arc or better stereo visual acuity. CONCLUSION: Secondary placement of an intraocular lens in the posterior chamber appears to be a safe, effective alternative for correction of aphakia in the contact lens- or spectacles-intolerant child or young adult.     

Production of inflammatory mediators and cytokine responsiveness of an SV40-transformed human proximal tubular epithelial cell line

PURPOSE: The clinical importance of the edge lift of rigid contact lenses is often neglected, possibly due to previous difficulties in its measurement. A new method of measuring axial edge lift (AEL) and radial edge lift (REL) using standard contact lens verification equipment, such as an optical spherometer, a thickness gauge, and contact lens V gauge, is described. METHODS: The technique was validated for trueness (accuracy) and precision (repeatability) by measuring the edge lift of a number of monocurve lenses, manufactured both with and without a normal edge finish. RESULTS: Edge lift was measured to an accuracy of 0.01 mm. CONCLUSIONS: As long as a mean of eight independent measurements of back optic zone radius (BOZR), sagitta, and one measurement of center thickness are taken, the pillar and collar technique is capable of producing accurate and repeatable measurements of the edge lift of a rigid contact lens.     

Antiretroviral therapy for pediatric and adolescent HIV

As the number of children infected in the HIV epidemic increases, the school nurse can play an important role in ensuring that these children receive comprehensive health care. Compliance with following an immunization program for HIV-infected children is a potential problem for various reasons. Many of these children come from homes where the mother also has HIV/AIDS. She is likely to be involved in keeping her family together, caring for her own health needs, and meeting financial and social needs of her family. Access to health care may be limited. The majority of vaccines administered within the first few months of life are parenteral and consist of inactivated antigens. Children or infants who are immunosuppressed may be unable to respond to the immunogen, thus rendering them susceptible to many infectious diseases. Heterosexual transmission and pregnancy compound the problems of HIV/AIDS (Flynn, 1994). Compliance following an immunization schedule becomes a greater challenge when working with the adolescent population. Parents may not understand that the risk of receiving vaccine, MMR for example, is less than the risk of severe complications associated with the diseases themselves. Coordination of care between the child, parent, and school district personnel is imperative to minimize the risk of further health-related problems of the HIV-infected child. Encouraging regular immunizations can decrease the child's susceptibility to infection, and administering medications properly can enhance the benefits of the drug therapy. An excellent resource for answering questions of school nurses related to HIV/AIDS is the National Pediatric and Family HIV Resource Center; contact Elaine Gross, R.N., M.S. at 1-800-362-0071.     

Methods of screening for dementia: a meta-analysis of studies comparing an informant questionnaire with a brief cognitive test

OBJECTIVE: The Canadian Ophthalmological Society was asked by the Royal Canadian Mounted Police (RCMP) and the Canadian Human Rights Commission to render an opinion on the acceptability of contact lenses as a reasonable accommodation to the uncorrected visual acuity standard. DESIGN: Survey by mailed questionnaire. SETTING: Canada. SUBJECTS: All RCMP general duty constables with a visual acuity code of V3, V4, V5 or V6 (n = 348) and a random sample of approximately 25% of the constables with an acuity code of V2 (n = 809). Of the 1040 questionnaires returned, 1037 were usable (final response rate 89.6%). Of the 1037 respondents 316 were in the V3 to V6 group and 721 were in the V2 group. OUTCOME MEASURES: Reported frequency of problems with spectacles or contact lenses, weighted according to sampling fraction. RESULTS: A total of 934 respondents indicated that they used some form of visual acuity correction while on duty; of the 934, 360 reported that they wore contact lenses at least some of the time. Approximately 75% of the spectacle wearers reported having to remove their spectacles because of fogging or rain. Although contact lens dislogement or fogging (21.2%) was less frequent than spectacle dislogement (59.2%), 35.4% of the contact lens wearers reported that they were unable to wear their lenses because of irritation on at least one occasion in the previous 2 years; the median length of time was 3.14 days. When the additional amount of time due to other causes is factored in, it is clear that contact lens users wear spectacles for substantial periods while on duty. CONCLUSIONS: Not only are RCMP general duty constables who usually wear contact lenses likely to have to wear spectacles at some time, but it is also possible that they will have to remove their spectacles and function in an uncorrected state in critical situations. Thus, altering the current standard to allow the use of contact lenses as a reasonable accommodation would not ensure effective and safe job performance.     

The peripheral blood levels of TNF alpha and PLA2 activities in dialysis and non-dialysis patients with uremia

PURPOSE: The purpose of our study was to assess the long-term tolerance of aphakic contact lenses in an elderly male population. METHODS: We conducted a follow-up study of Bausch & Lomb CW 79 aphakic extended wear contact lenses fit since 1982. A total of 109 patients (115 eyes) were identified. Records of 37 patients (43 eyes) were available to determine the course of contact lens wear. RESULTS: Thirty-six eyes were contact lens dropouts. The average time to failure was 22 months. Seventeen eyes from the failure group elected to receive secondary intraocular lenses (IOLs). Seven eyes were still wearing CW 79 contact lenses at the conclusion of the study. The average length of wear in these seven eyes was 91 months. CONCLUSIONS: We concluded that the CW 79 aphakic extended wear contact lenses were successful in selected cases. However, a high failure rate was found on long-term follow-up, and approximately half of the failure were converted to secondary IOLs.     

Complex refractive errors in pediatric patients: cause, management, and criteria for success

BACKGROUND: Uncorrected refractive error in children is an important contributor to permanent neurological visual impairment (amblyopia). Spectacles are often inadequate for certain refractive errors that occur in the pediatric population. Therefore, the purpose of this paper is to present the diagnostic and therapeutic considerations of infants and children referred to a hospital specialty contact lens practice during a 30-month period. METHODS: A retrospective cohort design was used to study patients 12 years or younger referred to a hospital-based contact lens service and cared for by the author. Sixty patients were first examined during the enrollment period. Follow-up data were collected after a period of no less than 3 years from the initial visit. Success with the prescribed therapy was assessed by comparing the final method of optical correction with that prescribed at the initial presentation. RESULTS: Aphakia and trauma were the two most common causes for referral, representing 57% of the patients younger than age 12. Contact lenses were prescribed for 51 of the 60 patients (85%) at presentation. Seventy-five percent of patients with unilateral aphakia attributable to congenital cataract were wearing a contact lens at the most recent follow-up examination. This was reduced to 60% with aphakia after trauma and just 50% with bilateral aphakia. The frequency of a visual acuity of 20/40 or better was 67% for bilateral aphakia, 47% after trauma with aphakia, and 25% for unilateral aphakia. CONCLUSIONS: The results presented here suggest that patients with unilateral aphakia attributable to congenital cataract have the most consistent contact lens wear, followed by patients with unilateral aphakia attributable to trauma. Patients with bilateral aphakia were more likely to have changed to spectacle lens wear. Patients wearing contact lenses at the most recent follow-up examination were more likely to have good visual acuity.     

The role of Pseudomonas aeruginosa biofilm in the attachment of Acanthamoeba to four types of hydrogel contact lens materials

PURPOSE: The effect of the previous coating of a contact lens surface with Pseudomonas biofilm on adsorption of Acanthamoeba onto four types of hydrogel materials was investigated. METHODS: Hydrogel contact lens quarters from each of the four FDA groups of hydrogel materials were incubated for at least 12 h in a suspension of 10(7)/ml of Pseudomonas aeruginosa (ATCC 27853) to coat their surfaces with biofilm. After rinsing, the lenses were incubated for 90 min in 5 x 10(5)/ml of Acanthamoeba castellanii trophozoites. New, uncoated lens quarters were incubated in the Acanthamoeba suspension as controls. After rinsing, all adsorbed trophozoites on one surface of each lens quarter were counted by direct light microscopy. Adsorption was expressed as numbers of amoebae per square centimeter of lens surface, and nonparametric data analysis was performed. RESULTS: Acanthamoeba adsorption to new, uncoated lenses was greater for ionic materials (groups 3 and 4) than for the nonionic materials (groups 1 and 2). Pseudomonas biofilm increased adsorption on all four lens types. CONCLUSION: Pseudomonas biofilm enhanced adsorption of Acanthamoeba on all lens types studied, but the adsorption to nonionic materials was significantly less. This suggests that all lens wearers may be at increased risk for Acanthamoeba infection if lenses are previously contaminated with bacterial biofilm, but this risk may be reduced by the use of certain lens types (low water content, nonionic materials).     

Pediatric cataract management with variations in surgical technique and aphakic optical correction

PURPOSE: The purpose of the study was to compare the results of three techniques of cataract surgery in children. Two methods included intraocular lens (IOL) implantation and one used contact lens correction of aphakia. DESIGN: Nonrandomized clinical trial. PARTICIPANTS: Seventy-seven eyes of 50 children between the ages of 2 1/2 and 16 years who had cataract surgery for the treatment of uncomplicated cataract. INTERVENTION: Thirty-one eyes underwent a "conventional" style of implantation, and a "phaco-style" of surgery was used in 24 eyes. A contact lens was used as the primary means of aphakic correction in 22 eyes. MAIN OUTCOME MEASURES: The visual results and complications of each type of surgery were compared. RESULTS: Corrected visual acuities did not differ significantly between the three groups 6 months after surgery. The incidence and type of complications were significantly different. Better lens centration, less long-term iris changes, or wound-related problems were observed with "phaco-style" modification of the technique of IOL insertion. CONCLUSIONS: Pediatric IOL insertion eliminated the need for contact lens wear and did not lead to a significantly different corrected visual acuity 6 months after surgery compared with lensectomy with contact lens correction. Adoption of some of the techniques of modern small-incision cataract surgery for pediatric IOL procedures produces a significant reduction in postoperative anterior segment complications compared with a standard limbal approach. Such modifications allow pediatric IOL insertion to be a safe alternative for the correction of pediatric aphakia.