To establish the absolute risk of contact lens (CL)-related microbial keratitis, the incidence of vision loss and risk factors for disease.
A prospective, 12-month, population-based surveillance study.
New cases of CL-related microbial keratitis presenting in Australia over a 12-month period were identified through surveillance of all ophthalmic practitioners (numerator). Case detection was augmented by records' audits at major ophthalmic centers. The denominator (number of wearers of different CL types in the community) was established using a national telephone survey of 35,914 individuals.
Cases and controls were interviewed by telephone to determine subject demographics and CL wear history. Visual outcomes were determined 6 months after the initial event. Annualized incidence and confidence intervals (CI) were estimated for different severities of disease and multivariable analysis was used in risk factor analysis.
Annualized incidence (with CI) of disease and vision loss by CL type and wear modality and identification of independent risk factors.
We identified 285 eligible cases of CL-related microbial keratitis and 1798 controls. In daily wear rigid gas-permeable CL wearers, the annualized incidence per 10,000 wearers was 1.2 (CI, 1.1-1.5); in daily wear soft CL wearers 1.9 (CI, 1.8-2.0); soft CL wearers (occasional overnight use) 2.2 (CI, 2.0-2.5); daily disposable CL wearers 2.0 (CI, 1.7-2.4); daily disposable CL wearers (occasional overnight use) 4.2 (CI, 3.1-6.6); daily wear silicone hydrogel CL wearers 11.9 (CI, 10.0-14.6); silicone hydrogel CL wearers (occasional overnight use) 5.5 (CI, 4.5-7.2); overnight wear soft CL wearers 19.5 (CI, 14.6-29.5) and in overnight wear of silicone hydrogel 25.4 (CI, 21.2-31.5). Loss of vision occurred in 0.6 per 10,000 wearers. Risk factors included overnight use, poor storage case hygiene, smoking, Internet purchase of CLs, <6 months wear experience, and higher socioeconomic class.
Incidence estimates for soft CL use were similar to those previously reported. New lens types have not reduced the incidence of disease. Overnight use of any CL is associated with a higher risk than daily use.
"Furthermore Wu et al.  reported that wearers purchasing lenses from Internet suppliers are more likely to overlook aftercare visits. This cohort of patients has also been associated with a higher risk of developing serious complications, such as microbial keratitis . Internet supply of contact lenses poses additional threats to optometric practices, by directly impacting sales and indirectly affecting the awareness of the practice by reducing footfall . "
[Show abstract][Hide abstract] ABSTRACT: Background
Optometric practices offer contact lenses as cash sale items or as part of monthly payment plans. With the contact lens market becoming increasingly competitive, patients are opting to purchase lenses from supermarkets and Internet suppliers. Monthly payment plans are often implemented to improve loyalty. This study aimed to compare behavioural loyalty between monthly payment plan members and non-members.
BBR Optometry Ltd offers a monthly payment plan (Eyelife™) to their contact lens wearers. A retrospective audit of 38 Eyelife™ members (mean ± SD: 42.7 ± 15.0 years) and 30 non-members (mean ± SD: 40.8 ± 16.7 years) was conducted. Revenue and profits generated, service uptake and product sales between the two groups were compared over a fixed period of 18 months.
Eyelife™ members generated significantly higher professional fee revenue (P < 0.001), £153.96 compared to £83.50, and profits (P < 0.001). Eyelife™ members had a higher uptake of eye examinations (P < 0.001). The 2 groups demonstrated no significant difference in spectacle sales by volume (P = 0.790) or value (P = 0.369). There were also no significant differences in contact lens revenue (P = 0.337), although Eyelife™ members did receive a discount. The Eyelife™ group incurred higher contact lens costs (P = 0.037), due to a greater volume of contact lens purchases, 986 units compared to 582.
Monthly payment plans improve loyalty among contact lens wearers, particularly service uptake and volume of lens purchases. Additionally the greater professional fees generated, render monthly payment plans an attractive business model and practice builder.
"The tears play a major role in delivering adequate oxygen to the cornea and maintaining adequate lubrication for the cornea. Studies have shown that continuous overnight use of CL is a major risk factor for corneal ulcer formation.8 CL wear during sleep results in reduced tear flow and oxygen delivery to the cornea. "
[Show abstract][Hide abstract] ABSTRACT: Purpose:
To review the microbiologic profile, clinical course, treatment, and outcome of patients with cosmetic contact lens (CL)-associated ulcerative keratitis.
Materials and Methods:
Observational noncomparative case series selected from an ongoing prospective series. Forty-six subjects examined at a corneal specialty practice in Abha, southern Saudi Arabia between April 2012 and June 2013, who presented with corneal stromal infiltrate on slit-lamp examination, were included in the study.
All patients were emmetropic, and lenses were worn solely for cosmetic purposes. Nine (19.5%) of 46 CL-wearing patients presented with laboratory-proven infectious keratitis. Pseudomonas was the most common organism (6/9; 66.6%). Staphylococcus species were the second most common, occurring in two (22.2%) of the nine cases. Streptococcus viridans in one case (11%). Laboratory-based medical therapy led to the healing of ulcers in all cases. Thirty-seven (80.4%) patients had sterile infiltrates.
Over-the-counter use of cosmetic lenses is rapidly increasing. The easy availability of these lenses is resulting in severe sight-threatening complications in some young emmetropic individuals. Prompt treatment of microbial keratitis is important to prevent vision loss.
Middle East African journal of ophthalmology 07/2014; 21(3):232-5. DOI:10.4103/0974-9233.134677
"Several risk factors for MK have been identified, the most common ones being contact lens use in the young and ocular surface diseases in the elderly; these render the corneal epithelium more vulnerable to microbial infection . In the developed world, wearing contact lenses is probably the most important risk factor for MK, particularly in individuals with healthy eyes . MK is caused by a variety of microorganisms, with Pseudomonas aeruginosa (P. "
[Show abstract][Hide abstract] ABSTRACT: Pseudomonas aeruginosa (P. aeruginosa) microbial keratitis (MK) is a sight-threatening disease. Previous animal studies have identified an important contribution of the complement system to the clearance of P. aeruginosa infection of the cornea. Mannose-binding lectin (MBL), a pattern recognition receptor of the lectin pathway of complement, has been implicated in the host defense against P. aeruginosa. However, studies addressing the role of the lectin pathway in P. aeruginosa MK are lacking. Hence, we sought to determine the activity of the lectin pathway in human MK caused by P. aeruginosa.
Primary human corneal epithelial cells (HCECs) from cadaveric donors were exposed to two different P. aeruginosa strains. Gene expression of interleukin (IL)-6, IL-8, MBL, and other complement proteins was determined by reverse transcription-polymerase chain reaction (RT-PCR) and MBL synthesis by enzyme-linked immunosorbent assay and intracellular flow cytometry.
MBL gene expression was not detected in unchallenged HCECs. Exposure of HCECs to P. aeruginosa resulted in rapid induction of the transcriptional expression of MBL, IL-6, and IL-8. In addition, expression of several complement proteins of the classical and lectin pathways, but not the alternative pathway, were upregulated after 5 h of challenge, including MBL-associated serine protease 1. However, MBL protein secretion was not detectable 18 h after challenge with P. aeruginosa.
MK due to P. aeruginosa triggers activation of MBL and the lectin pathway of complement. However, the physiologic relevance of this finding is unclear, as corresponding MBL oligomer production was not observed.
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