Post-acute phase and sequelae management of epidermal necrolysis: an international, multidisciplinary DELPHI-based consensus

BACKGROUND

Long-term sequelae are frequent and often disabling after epidermal necrolysis (Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN)). However, consensus on the modalities of management of these sequelae is lacking.

OBJECTIVES

We conducted an international multicentric DELPHI exercise to establish a multidisciplinary expert consensus to standardize recommendations regarding management of SJS/TEN sequelae.

METHODS

Participants were sent a survey via the online tool "Survey Monkey" consisting of 54 statements organized into 8 topics: general recommendations, professionals involved, skin, oral mucosa and teeth, eyes, genital area, mental health, and allergy workup. Participants evaluated the level of appropriateness of each statement on a scale of 1 (extremely inappropriate) to 9 (extremely appropriate). Results were analyzed according to the RAND/UCLA Appropriateness Method.

RESULTS

Fifty-two healthcare professionals participated. After the first round, a consensus was obtained for 100% of 54 initially proposed statements (disagreement index < 1). Among them, 50 statements were agreed upon as 'appropriate'; four statements were considered 'uncertain', and ultimately finally discarded.

CONCLUSIONS

Our DELPHI-based expert consensus should help guide physicians in conducting a prolonged multidisciplinary follow-up of sequelae in SJS-TEN.

Adding value to remote monitoring: Co-design of a health literacy intervention for older people with chronic disease delivered by telehealth - The telehealth literacy project

OBJECTIVE

To co-design, test and evaluate a health literacy, chronic disease self-management and social support intervention for older people delivered by group videoconferencing into the home.

METHOD

The Telehealth Literacy Project (THLP) was a mixed methods, quasi-experimental, non-randomised trial nested within a telehealth remote monitoring study. An intervention group (n = 52) participated in five, weekly videoconference group meetings lasting for 1.5 h and a control group (n = 60) received remote monitoring only. Outcomes were measured using the nine-scale Health Literacy Questionnaire (HLQ) and two scales of the Health Education Impact Questionnaire (heiQ). Semi-structured interviews and focus group data were thematically analysed.

RESULT

At 3 month follow-up, univariate analysis identified small effects in the intervention group only, with improved health literacy behaviours (five HLQ scales) and self-management skills (two heiQ scales). ANOVA of HLQ scales indicated no significant differences between the two groups over time indicating a contributing effect of the remote monitoring project. Intervention participants reported improved perception of companionship, emotional and informational support.

CONCLUSION

The THLP delivered with telemonitoring indicates potential to improve social support and some health literacy factors in older people.

PRACTICE IMPLICATIONS

Patient education can be delivered by group videoconferencing.

Telehealth Interventions Delivering Home-based Support Group Videoconferencing: Systematic Review

BACKGROUND

Group therapy and education and support sessions are used within health care across a range of disciplines such as chronic disease self-management and psychotherapy interventions. However, there are barriers that constrain group attendance, such as mobility, time, and distance. Using videoconferencing may overcome known barriers and improve the accessibility of group-based interventions.

OBJECTIVE

The aim of this study was to review the literature to determine the feasibility, acceptability, effectiveness, and implementation of health professional-led group videoconferencing to provide education or social support or both, into the home setting.

METHODS

Electronic databases were searched using predefined search terms for primary interventions for patient education and/or social support. The quality of studies was assessed using the Mixed Methods Appraisal Tool. We developed an analysis framework using hierarchical terms feasibility, acceptability, effectiveness, and implementation, which were informed by subheadings.

RESULTS

Of the 1634 records identified, 17 were included in this review. Home-based groups by videoconferencing are feasible even for those with limited digital literacy. Overall acceptability was high with access from the home highly valued and little concern of privacy issues. Some participants reported preferring face-to-face groups. Good information technology (IT) support and training is required for facilitators and participants. Communication can be adapted for the Web environment and would be enhanced by clear communication strategies and protocols. A range of improved outcomes were reported but because of the heterogeneity of studies, comparison of these across studies was not possible. There was a trend for improvement in mental health outcomes. Benefits highlighted in the qualitative data included engaging with others with similar problems; improved accessibility to groups; and development of health knowledge, insights, and skills. Videoconference groups were able to replicate group processes such as bonding and cohesiveness. Similar outcomes were reported for those comparing face-to-face groups and videoconference groups.

CONCLUSIONS

Groups delivered by videoconference are feasible and potentially can improve the accessibility of group interventions. This may be particularly useful for those who live in rural areas, have limited mobility, are socially isolated, or fear meeting new people. Outcomes are similar to in-person groups, but future research on facilitation process in videoconferencing-mediated groups and large-scale studies are required to develop the evidence base.

Delivering patient education by group videoconferencing into the home: Lessons learnt from the Telehealth Literacy Project

We examined the procedures for implementing group videoconference (VC) education for older people delivered into the home environment to identify the most common themes affecting the optimum delivery of VC home-based groups to older people. Participants (n = 52) were involved in a six-week group VC patient education program. There were a total of 44 sessions, undertaken by nine groups, with an average of four participants (range 1-7) and the facilitator. Participants could see and hear each other in real-time whilst in their homes with customised tablets or a desktop computer. The data presented here are based on a program log maintained by the facilitator throughout the implementation phase of the project and post intervention. The VC group experience is influenced by factors including the VC device location, connection processes, meeting times, use of visual aids and test calls. Social presence can be improved by communication protocols and strategies. Robust information technology (IT) support is essential in mitigating technical problems to enhance users' experience. Group patient education can be delivered by VC into homes of older people. However, careful pre-program planning, training and support should be considered when implementing such programs.

Can videoconferencing affect older people's engagement and perception of their social support in long-term conditions management: a social network analysis from the Telehealth Literacy Project

Social support is a key component in managing long-term conditions. As people age in their homes, there is a greater risk of social isolation, which can be ameliorated by informal support networks. This study examined the relationship between changes in social support networks for older people living in a regional area following weekly videoconference groups delivered to the home. Between February and June 2014, we delivered 44 weekly group meetings via videoconference to participants in a regional town in Australia. The meetings provided participants with education and an opportunity to discuss health issues and connect with others in similar circumstances. An uncontrolled, pre-post-test methodology was employed. A social network tool was completed by 45 (87%) participants either pre- or post-intervention, of which 24 (46%) participants completed the tool pre- and post-intervention. In addition, 14 semi-structured interviews and 4 focus groups were conducted. Following the intervention, participants identified increased membership of their social networks, although they did not identify individuals from the weekly videoconference groups. The most important social support networks remained the same pre- and post-intervention namely, health professionals, close family and partners. However, post-intervention participants identified friends and wider family as more important to managing their chronic condition compared to pre-intervention. Participants derived social support, in particular, companionship, emotional and informational support as well as feeling more engaged with life, from the weekly videoconference meetings. Videoconference education groups delivered into the home can provide social support and enhance self-management for older people with chronic conditions. They provide the opportunity to develop a virtual social support network containing new and diverse social connections.

Systematic review of integrated models of health care delivered at the primary-secondary interface: how effective is it and what determines effectiveness?

Integrated multidisciplinary care is difficult to achieve between specialist clinical services and primary care practitioners, but should improve outcomes for patients with chronic and/or complex chronic physical diseases. This systematic review identifies outcomes of different models that integrate specialist and primary care practitioners, and characteristics of models that delivered favourable clinical outcomes. For quality appraisal, the Cochrane Risk of Bias tool was used. Data are presented as a narrative synthesis due to marked heterogeneity in study outcomes. Ten studies were included. Publication bias cannot be ruled out. Despite few improvements in clinical outcomes, significant improvements were reported in process outcomes regarding disease control and service delivery. No study reported negative effects compared with usual care. Economic outcomes showed modest increases in costs of integrated primary-secondary care. Six elements were identified that were common to these models of integrated primary-secondary care: (1) interdisciplinary teamwork; (2) communication/information exchange; (3) shared care guidelines or pathways; (4) training and education; (5) access and acceptability for patients; and (6) a viable funding model. Compared with usual care, integrated primary-secondary care can improve elements of disease control and service delivery at a modestly increased cost, although the impact on clinical outcomes is limited. Future trials of integrated care should incorporate design elements likely to maximise effectiveness.

Multi-site videoconferencing for home-based education of older people with chronic conditions: the Telehealth Literacy Project

We examined the acceptability of multi-site videoconferencing as a method of providing group education to older people in their homes. There were 9 groups comprising 52 participants (mean age 73 years) with an average of four chronic conditions. Tablet computers or PCs were installed in participant's homes and connected to the Internet by the National Broadband Network (high-speed broad band network) or by the 4G wireless network. A health literacy and self-management programme was delivered by videoconference for 5 weeks. Participants were able to view and interact with all group members and the facilitator on their devices. During the study, 44 group videoconferences were conducted. Evaluation included 16 semi-structured interviews, 3 focus groups and a journal detailing project implementation. The participants reported enjoying home-based group education by videoconference and found the technology easy to use. Using home-based groups via videoconference was acceptable for providing group education, and considered particularly valuable for people living alone and/or with limited mobility. Audio difficulties were the most commonly reported problem. Participants connected with 4G experienced more problems (audio and visual) than participants on the National Broadband Network and those living in multi-dwelling residences reported more problems than those living in single-dwelling residences. Older people with little computer experience can be supported to use telehealth equipment. Telehealth has the potential to improve access to education about chronic disease self-management.

The internet as a source of health information in three disparate communities

A survey questionnaire was designed and implemented across three different communities to determine the current utilisation, importance, trust and future preference for the internet as a source of health information in three different socioeconomic groups. The following were the key results. Fewer respondents in the low socioeconomic group accessed online health information than the mid-high socioeconomic or university samples. The internet was a much more important source of health information for the university sample. The use of online health information and the importance ascribed to the internet as a source of health information was related to home internet access and the frequency of internet use in all three populations. Most respondents do not bring online health information to their doctor (>70% of those who access online health information). Age alone did not relate to the current use of the internet as a source of health information. Most respondents in all populations did not trust the internet. In all populations the internet was a more preferred source of health information than its current use would suggest, especially among those with home internet access and frequent users of the internet.

Community health information sources--a survey in three disparate communities

OBJECTIVE

To determine the current utilisation, importance, trust and future preference for contemporary sources of health information in three different socioeconomic groups.

DESIGN

A pilot study including key informant interviews and direct observation was conducted in a low socioeconomic community. From this work a survey questionnaire was designed and implemented across three different communities.

PARTICIPANTS AND SETTING

Semi-structured key informant interviews and focus groups capturing 52 respondents. Paper-based surveys were left in community organisations and local health practices in a low socioeconomic (LSE) community on the outskirts of Ipswich, Queensland, a mid-high socioeconomic (MSE) community in the western suburbs of Brisbane, and at a local university.

MAIN OUTCOME MEASURES

Rank of current and preferred future sources of health information, importance and trustworthiness of health information sources.

RESULTS

Across all three communities the local doctor was the most currently used, important, trusted and preferred future source of health information. The most striking difference between the three communities related to the current use and preferred future use of the internet. The internet was a more currently used source of health information and more important source in the university population than the LSE or MSE populations. It was also a less preferred source of future health information in the LSE population than the MSE or university populations. Importantly, currently used sources of health information did not reflect community members' preferred sources of health information.

CONCLUSIONS

People in different socioeconomic communities obtain health information from various sources. This may reflect access issues, education and awareness of the internet as a source of health information, less health information seeking as well as a reluctance by the e-health community to address the specific needs of this group.

n=1: Some challenges and opportunities for integrating patient care

I AM A JUNIOR DOCTOR working in a Brisbane hospital. I recently completed a PhD investigating the use of eHealth strategies to improve community access to relevant health information, with a particular focus on low socioeconomic communities and their needs.1 Like many products of the postgraduate medical course, I came to medicine after studying other disciplines ? economics and government as part of a Bachelor of Arts, and medical sciences as part of a Bachelor of Science. I?ve long had an interest in policy, and after several years of communitybased field work in a community with an average household income of $25 000, and two years of hospital-based clinical experience, I have come to realise that the health system fails to integrate services to provide a systematic approach to dealing with patients? needs. In this n=1 I outline some of the deficiencies I encounter in everyday clinical practice, from admission to discharge, and beyond, to community- based care. Let me make it clear at the outset that I believe these deficits do not arise from a lack of compassion or care on the behalf of dedicated clinicians and hospital support staff, but rather from a system failure. Indeed, in my own experience, most health care workers give too much, to the detriment of their own health and quality of life. Some of my comments are supported by ?systematic research? (fieldbased observation and survey data), while others come from my own daily encounters.

Evaluation for farming systems improvement: looking backwards, thinking forwards

Based on personal reflection, this paper presents program evaluation as a vehicle to bring about better project results and perhaps even a better world. New paradigm approaches to farming systems improvement feature multiple collaborators in work that is increasingly participatory, process-oriented and diverse in outcome. This is often accompanied by pressure for rapid feedback and dialogue. Conventional objectives-based evaluation methods are insufficient to capture the range of unanticipated outcomes that this work may produce, and may be incompatible with a participatory ethos. In the contemporary farming systems improvement context, evaluation is most valuable when it has short-cycles and fosters reflection. Two contrasting techniques that offer promise for meeting these needs are the most significant change technique, and participatory approaches to program logic. Presenting a radical departure from conventional monitoring against quantitative indicators, most significant change technique involves the regular collection and participatory interpretation of ‘stories’ about change rather than predetermined quantitative indicators. Program logic is the rationale behind a program or project — what are understood to be the cause and effect relationships between project activities, outputs, intermediate outcomes, and ultimate outcomes. When done in group situations, program logic offers many benefits by enabling participants to question the cause and effect assumptions to improve project design. These techniques can supplement traditional approaches; closing some of the information gaps identified by contemporary farming systems improvement work.

Corneal toxicity: the epithelium and stroma in iatrogenic and factitious disease

Corneal toxicity is caused by chemical trauma and by iatrogenic and factitious disease, which are often overlooked, and which are reviewed here. The clinical signs of iatrogenic disease are usually nonspecific and identical to those resulting from other causes of surface disease. Factitious disease is either the result of mechanical trauma or the abuse of toxic eye drops. One epidemiological study, in a tertiary setting, identified 13% of keratoconjunctivitis cases as iatrogenic. Healing was prolonged taking 7-93 (median 28.5) days. Pathogenic mechanisms vary widely with different drugs and include subclinical scarring, pseudopemphigoid, drug-induced ocular cicatricial pemphigoid, and toxic follicular reactions. There is little readily available data either on the probability of the development of adverse reactions or for the comparison of different drugs. The assessment of the toxicity of topical drugs is currently by the Draize test in rabbits. New in vitro tests on human corneal epithelial cell cultures include ATP assays for cell viability, scanning EM of epithelial microvilli, and vital staining to assess cell membrane permeability and intracellular esterase. Despite their simplicity, these test systems can correlate well with clinical toxicity and provide a toxicity index for drug comparisons. Treatment requires drug withdrawal or substitution by non-preserved and less toxic preparations. Factitious injury is rare, difficult to diagnose, and should only be considered when all other diagnoses have been excluded. Prevention requires a high level of awareness of the potential for iatrogenic disease, particularly in the high-risk setting of chronic ocular surface disease.

Use of myocardial backscatter as a quantitative tool for dobutamine echocardiography: feasibility, response to ischemia and accuracy compared with coronary angiography

BACKGROUND

Integrated backscatter (IB) changes with ischemia, but most prior studies have involved parasternal imaging, which limited the number of evaluable segments. We sought to assess the efficacy and feasibility of IB from the apical views, and compare this to myocardial Doppler findings and wall motion analysis during dobutamine echocardiography.

METHODS AND RESULTS

Forty-one patients undergoing dobutamine echocardiography had gray scale images and color myocardial Doppler acquired in three apical views. Cyclic variation IB (CVIB), time to peak IB (tIB, corrected for QT interval) and Doppler peak velocity (PV) in the same segment at rest and peak stress were assessed offline from digital cineloops at 80-120 frames/s. Significant coronary disease was defined by quantitative angiography as > 50% stenosis. Analysis of the waveform in the apical views was feasible in 82% of segments. The backscatter curve was shown to be biphasic, with correlation of the first peak with peak tissue velocity, and significant regional variation. However, the response to normal segments was different with tissue Doppler (increased velocity) and backscatter (no change). Ischemia was associated with a lower peak tissue velocity and lower CVIB. Only resting tissue velocity and tIB (not CVIB) distinguished scar from ischemic segments. Using an optimal cutoff of < 5.3 dB at rest achieved a sensitivity of 55%, a specificity of 76% and an accuracy of 75% when compared to angiography. The same cutoff at peak achieved a sensitivity of 58%, a specificity of 80% and an accuracy of 76%.

CONCLUSIONS

CVIB and tissue velocity responses to stress are different, but both may be used to identify abnormal segments in patients with CAD. However, while measurement of CVIB is feasible in the apical views, the variability caused by anisotropy limits the accuracy of a single cutoff.

Use of cyclic variation of integrated backscatter to assess contractile reserve and myocardial viability in chronic ischemic left ventricular dysfunction

The detection of viable myocardium has important implications for management, but use of stress echocardiography to detect this is subjective and requires exposure to dobutamine. We investigated whether cyclic variation (CV) of integrated backscatter (IB) from the apical views could provide a resting study for detection of contractile reserve (CR) and prediction of myocardial viability in 27 patients with chronic ischemic left ventricular (LV) dysfunction. Repeat echocardiography was performed after 6.7 +/- 3.8 months of follow-up; 14 patients underwent revascularization and 13 were treated medically. Using a standardized dobutamine echocardiography (DbE) protocol, images from three apical views were acquired at 80-120 frames/sec at rest and during stress. CR was identified if improvement of wall motion was observed at low dose (5 or 10 microg/kg/min) DbE. Myocardial viability was characterized by improvement at follow-up echocardiography in patients with revascularization. CVIB at rest and low dose dobutamine were assessed in 194 segments with resting asynergy (severe hypokinesis or akinesis), of which 88 (45%) were in patients who underwent revascularization. Of these, CVIB could be measured in 190 (98%) segments at rest and 185 (95%) at low dose dobutamine. Sixty-two (33%) segments had CR during low dose DbE and 50 (57%) segments showed wall-motion recovery (myocardial viability) at follow-up echocardiography. Segments with CR had significantly higher CVIB at rest (P < 0.001) and low dose dobutamine (P = 0.005) than segments without CR. Using optimal thresholds of CVIB (> 8.2 dB) at rest, the accuracy of CVIB for detecting CR was 70%. Compared with nonviable segments, viable segments had significantly higher CVIB at rest (P < 0.001) and low dose dobutamine (P < 0.001). Using optimal thresholds of CVIB (> 5.3 dB) at rest, the accuracy of CVIB for detecting myocardial viability was 85%, which was higher than that in conventional DbE (62%, P < 0.01). Thus, assessment of CVIB from the apical views is a feasible and accurate tool for detecting CR and predicting myocardial viability in chronic LV dysfunction.

Assessment of regional long-axis function during dobutamine echocardiography

Echocardiographic analysis of regional left ventricular function is based upon the assessment of radial motion. Long-axis motion is an important contributor to overall function, but has been difficult to evaluate clinically until the recent development of tissue Doppler techniques. We sought to compare the standard visual assessment of radial motion with quantitative tissue Doppler measurement of peak systolic velocity, timing and strain rate (SRI) in 104 patients with known or suspected coronary artery disease undergoing dobutamine stress echocardiography (DbE). A standard DbE protocol was used with colour tissue Doppler images acquired in digital ciné-loop format. Peak systolic velocity (PSV), time to peak velocity (TPV) and SRI were assessed off-line by an independent operator. Wall motion was assessed by an experienced reader. Mean PSV, TPV and SRI values were compared with wall motion and the presence of coronary artery disease by angiography. A further analysis included assessing the extent of jeopardized myocardium by comparing average values of PSV, TPV and SRI against the previously validated angiographic score. Segments identified as having normal and abnormal radial wall motion showed significant differences in mean PSV (7.9 +/- 3.8 and 5.9 +/- 3.3 cm/s respectively; P < 0.001), TPV (84 +/- 40 and 95 +/- 48 ms respectively; P = 0.005) and SRI (-1.45 +/- 0.5 and -1.1 +/- 0.9 s(-1) respectively; P < 0.001). The presence of a stenosed subtending coronary artery was also associated with significant differences from normally perfused segments for mean PSV (8.1+/-3.4 compared with 5.7+/-3.7 cm/s; P < 0.001), TPV (78 +/- 50 compared with 92 +/- 45 ms; P < 0.001) and SRI (-1.35 +/- 0.5 compared with -1.20 +/- 0.4 s(-1); P = 0.05). PSV, TPV and SRI also varied significantly according to the extent of jeopardized myocardium within a vascular territory. These results suggest that peak systolic velocity, timing of contraction and SRI reflect the underlying physiological characteristics of the regional myocardium during DbE, and may potentially allow objective analysis of wall motion.

Split thickness buccal mucous membrane grafts and beta irradiation in the treatment of recurrent pterygium

BACKGROUND

Pterygium is a common problem and after surgical removal may recur in up to 80% of cases, depending on the technique of primary excision. Recurrent pterygia can be aggressive and repeated excision may result in severe conjunctival scarring and shortening, resulting in insufficient conjunctiva to perform further grafting and lid surgery. When there is insufficient autologous conjunctiva, mucous membrane must be obtained from other sites. Full thickness buccal mucous membrane grafts have been described, but they may result in a beefy red appearance, with graft contraction and a poor tear film.

METHOD

The use of split thickness buccal mucous membrane grafts is described in three patients with recurrent pterygium, two in combination with lamellar keratoplasty. beta Irradiation was used as adjuvant therapy in all cases.

RESULTS

In all three cases an acceptable cosmetic appearance was achieved, with no recurrence of the pterygium, and a good range of eye movements.

CONCLUSIONS

It is recommended that split thickness buccal mucosal grafts, combined with beta irradiation, should be considered in complex cases of pterygium recurrence when there is insufficient autologous conjunctiva and conjunctival shortening with restricted eye movements.

Natural history of recurrent erosion syndrome--a 4 year review of 117 patients

AIMS/BACKGROUND

Recurrent erosion syndrome encompasses a group of mixed aetiologies for which there are a number of methods of management which may influence the course of the disease.

METHODS

The outcomes of a cohort of patients initially treated with topical lubricants were studied. 117 consecutive patients presenting over 1 year with a history of recurrent erosions were enrolled, baseline characteristics were documented, and treatment with lubricants was initiated. Patients were surveyed 4 years later inquiring about symptoms and treatments required.

RESULTS

A total of 94 (80%) of the initial cohort were contacted. The mean age was 44 years and the sex distribution was 44 males to 50 females. The mean period of follow up was 48 months. 55 (59%) were still symptomatic with attacks occurring at a median frequency of 60 days. 13 patients (24%) complained of an episode at least every week and 28 patients (51%) suffered at least every month. The median pain score (analogue scale of 1-10) was 2.5. Seventy five per cent (n = 21) of patients with epithelial basement membrane dystrophy (EBMD) were symptomatic compared with those with a traumatic aetiology among whom 46% (n = 28) were symptomatic. This difference was significant (p = 0.02). Those with EBMD were more likely to be continuing to use topical lubricants than the trauma group.

CONCLUSION

Patients with a traumatic aetiology are less likely to suffer chronic recurrent erosion syndrome than those with EBMD.

The inside story: why contact lens cases become contaminated

Contact lens case contamination has become an enigma, both because its role in the pathogenesis of lens-related keratitis has remained uncertain, and because current contact lens disinfection systems have been ineffective in eliminating it. This lecture reviews the evidence regarding the role of lens case contamination in the pathogenesis of keratitis and examines the reasons for the failure of disinfection systems to minimise lens case contamination.

Biomechanical analysis of two change-of-direction maneuvers while running

Many research efforts focus on unidirectional gait. However, few functional activities are exclusively linear: people regularly change directions to evade obstructions. Directional changes have been identified as particularly hazardous, but rarely studied. The purpose of this study was to examine the kinetics of abrupt changes of direction while running. Twelve adult volunteers performed 10 trials each for 45 degrees and 90 degrees change-of-direction conditions. Orthogonal force and moment (torque) records were obtained using a computer-interfaced force platform system. Vertical, braking, and propulsive force and applied torque variables were extracted for statistical analysis. Significant force differences (p < .01) were identified between conditions. Applied torques were highly variable and not significantly different. Functionally, these data suggest that applied forces serve as the principal impetus of directional change.

Pseudomonas keratitis associated with biofilm formation on a disposable soft contact lens

Images

Nonulcerative complications of contact lens wear. Relative risks for different lens types

A case-control study was used to evaluate the relative risk (RR) of acute contact lens-related disorders. The study sample comprised new patients wearing contact lens presenting at the accident and emergency department at Moorfields Eye Hospital, London, England, in 12 months. Disorders were classified by pathogenesis. Compared with gas-permeable hard contact lenses (the referent), extended-wear soft contact lenses were related to the largest overall RR for any complication (2.7 [95% confidence limits, 1.73, 4.16]), whereas for daily wear soft contact lenses the overall RR was 1.3 (confidence limits, 1.0, 1.72). Relative risks were greatest for extended-wear soft contact lens wearers with metabolic disorders (2.1 [confidence limits, 1.28, 3.4]) and for such wearers with sterile infiltrates (2.4 [confidence limits, 1.22, 4.84]). Among those using daily wear contact lenses, RR was highest for those with toxic/hypersensitivity disorders (5.9 [95% confidence limits, 3.27, 10.49]). Severe complications involving greater morbidity occurred more frequently with extended-wear soft contact lenses. This could be reduced by selecting a more appropriate lens type to correct low refractive errors.

Possible environmental sources of Acanthamoeba spp in contact lens wearers

The water supply and dust samples from the home environment (bathrooms and kitchens) of 50 wearers of contact lenses (CLs) were cultured for the presence of free-living amoebae. CL cases, solutions, and water taps were cultured for bacteria, which amoebae require for growth. Acanthamoeba spp were isolated from water drawn from six bathroom cold water taps (tank supplied), five in the presence of limescale, and from one kitchen cold water tap (mains supplied). There was an association between the presence of limescale in water and direct culture for free-living amoebae, suggesting that scale provides a favourable microenvironment for amoebae. Acanthamoebae were also found in dust from around one washbasin. Nineteen of 50 CL cases, 12/122 CL care rinsing solutions, and 59/100 cold water taps yielded Gram negative bacteria which could be ingested by amoebae. It is concluded from this study that CLs should not be washed in first-drawn tank-fed cold water, especially if limescale is present, and that soft CLs should be rinsed in manufactured single-use, sterile solutions. Rigid CL and CL cases should only be washed with boiled tap water (preferably hot), or single-use sterile solutions, and stored dry to prevent multiplication of amoebae and Gram negative bacteria.