Characteristics, Behaviors, and Awareness of Contact Lens Wearers Purchasing Lenses Over the Internet.

OBJECTIVES: To describe the characteristics and hygiene habits of contact lens (CL) wearers who acquire CLs over the Internet, as well as their awareness of modifiable risk factors (RFs). METHODS: A web-based survey was conducted among clients of an online CL sales platform during 6 months. Demographic data, CL hygiene-related awareness, and compliance were collected and analyzed. RESULTS: The questionnaire was completed by 1,264 CL wearers: the average age was 40.8 years; most were women (71.1%), had myopia (76.4%), and wore monthly disposable CLs (63.6%). The frequency of eye examination was significantly lower among those buying the CL exclusively online (15.8% vs. 6.6%, P<0.001) and those who had begun CL use on their own (17.5% vs. 8.8%, P<0.001). Initiation to CL wear without the intervention of an eye care practitioner was more frequent in wearers with less experience. Common risk behaviors included water exposure (68.1% in swimming and 64.9% in the shower), use of the case (61.9%) and CL (65.1%) beyond the recommended replacement time, and reuse of the maintenance solution (31.9%). Ignorance of recommended hygiene increased the probability of risky behavior. CONCLUSION: There were no differences in compliance or awareness of risks between those purchasing exclusively online and other CL wearers. However, the growing frequency of self-taught initiation in CL wear among less-experienced online customers and online exclusive purchase was associated with a decrease in eye examination frequency and therefore worse compliance and increased risks. This finding underlines the importance of publicizing correct hygiene habits by all possible means so as to increase compliance.

Spectacle prescriptions review to determine prevalence of ametropia and coverage of frequent replacement soft toric contact lenses.

PURPOSE: To determine the prevalence of ametropia and astigmatism in a clinic population and to estimate the coverage of frequent replacement soft toric lenses. METHODS: A review of patient files was conducted at three clinical sites. Prescription data collected between January 2014 and March 2017 in a patient cohort 14 to 70 years of age inclusive were analyzed to determine prevalence of ametropia and astigmatism. The percent coverage of frequent replacement soft toric contact lenses has further been estimated using different ranges for sphere, cylinder and axis availability. RESULTS: In total 101,973 patients were included in the analysis of which 69.5% were considered myopic, 26.9% hyperopic and 3.5% emmetropic as determined by the eye with the larger absolute value of the spherical equivalent refraction. Astigmatism in at least one eye was found in 87.2% of the population, with 37.0% of the patients exhibiting astigmatism of at least -1.00DC in at least one eye. With-the-rule astigmatism was most prevalent in the 14 to 20 year-olds (53.0%), while against-the-rule astigmatism was most prevalent in the 41 to 70 year-olds (50.7%). For astigmatic eyes with a cylinder of at least -0.75DC (n = 83,540; 41% of all eyes), the coverage with toric soft lenses varied greatly depending on parameter availability and ranged between 30.7% (sphere: Plano to -3.00D, cylinder: up to -1.75DC, axes: 90 ±â€¯10° and 180 ±â€¯10°) and 96.4% (sphere: + 6.00D to -10.00D, cylinders: up to -2.75DC, 18 axes). CONCLUSION: Currently available frequent replacement soft toric contact lenses provide coverage for up to 96.4% of potential patients.

Is purchasing lenses from the prescriber associated with better habits among soft contact lens wearers?

PURPOSE: To compare the habits of United States (US) soft contact lens (SCL) wearers who bought SCLs from their eye care practitioner (ECP), on the internet/telephone, or at retail (not where they were examined) to test the effect of proximity to the prescriber on SCL wear and care practices. METHODS: Adult SCL wearers completed an adapted Contact Lens Risk Survey (CLRS) online that queried items related to risk factors for SCL-related complications. Responses from subjects who purchased at the ECP, via the internet/telephone, or at a retail store were compared (Chi-Square). RESULTS: Purchase sources were: ECP 646 (67%, 44±12 yrs, 17% male), Retail 104 (11%, 45±13 yrs, 28% male), and Internet/telephone 218 (23%, 45±12 yrs, 18% male); age (p=0.51), gender (p=0.021). Internet purchasers had fewer annual eye exams (79% ECP, 83% retail, 66% internet/telephone, p=0.007), purchased more hydrogel SCLs (34% ECP, 29% retail, 45% internet/telephone, p=0.0034), and paid for SCLs with insurance less often (39% ECP, 29% retail, 19% internet/telephone, p<0.0001). Other behaviors were similar across groups (p>0.05). CONCLUSIONS: In this sample, the purchase location of SCL wearers had limited impact on known risk factors for SCL-related complications. Internet purchasers reported less frequent eye exams and were more likely to be wearing hydrogel SCLs. Closer access to the ECP through in-office SCL purchase did not improve SCL habits or reduce the prevalence of risk behaviors.

A theoretical model for comparing UK costs of contact lens replacement modalities.

PURPOSE: To develop a theoretical 'cost-per-wear' model of contact lens wear, as tool for UK practitioners to assist patients in determining the most cost-effective lens replacement and wearing frequency protocols. METHODS: The annual cost of professional fees, contact lenses and solutions when wearing daily, two weekly and monthly replacement contact lenses was determined for spherical, toric and multifocal prescription types. This annual cost was divided by the number times lenses are worn per year, resulting in a cost-per-wear. RESULTS: The cost-per-wear for two weekly and monthly replacement contact lenses is similar, both decreasing with increasing frequency of wear. The cost-per-wear of daily replacement lenses is lower than for reusable lenses when worn 1-2 days per week (DPW), but higher when worn 4-7 DPW. The 'cross-over point' for spherical lenses at which the cost-per-wear is virtually the same for the three replacement frequencies, approximately £2.06, occurs at 3 DPW. The cross-over point for toric lenses is at 4 DPW with daily compared to two weekly replacement lenses (£2.06) and between 2-3 DPW with daily compared to monthly replacement contact lenses (£2.39). The crossover point for multifocal lenses of all replacement frequencies is between 4 and 5 DPW (£1.79). CONCLUSIONS: In general, daily replacement contact lenses are more cost-effective when worn on a part-time basis (1-3 DPW) and reusable lenses are more cost-effective when worn full-time (4-7 DPW). This cost-per-wear model will assist practitioners in making an informed decision when offering advice to patients relating to the most suitable replacement modality.

The conformity of a soft contact lens on the eye.

An axisymmetric elastic shell deformation model has been created to predict the conformity of a soft contact lens when pressed against the eye. Regions of contact and gap may be predicted, and the nonuniform reaction pressure between the lens and eye may also be found. This is important for issues like abrasion and comfort. Bending, membrane and transverse shear loads within the lens are also computed. Commercial soft contact lenses and a representative eye shape are used for the examples. We find that the uniformity of loading against the eye is strongly affected by the degree to which the lens is shaped to fit the eye, and relatively unaffected by the thickness of the lens.

The socioeconomic aspects of laser refractive surgery.

Excimer laser photorefractive keratectomy (PRK) has shown promising results in preliminary studies. However, even if long-term safety and efficacy are demonstrated, questions have been raised about its viability from a cost-effectiveness perspective. We analyzed the economic investment of elective excimer laser PRK both from the societal and individual perspectives. When the present value of likely expenses associated with excimer laser PRK and follow-up care are compared with those entailed in wearing soft contact lenses, PRK is roughly equivalent to daily wear soft contact lenses over a 10-year horizon and considerably less expensive than extended-wear soft contact lenses. When the analytic perspective is extended to 20 years, excimer laser PRK is a less expensive investment than both daily wear and extended-wear soft contact lenses.

Disposable contact lens wear systems.

The majority of problems associated with soft lens wear in general are related to lens deterioration, deposits, care systems, and lack of patient compliance. The greatest problem with soft lenses is that they can never be totally cleaned. The point of a disposable lens wear program is to discard the lens while it is still in relatively good condition. If either the patient or the practitioner wishes to use the lens until problems occur, the entire system is rendered useless. Practitioners must emphasize to new patients that soft lenses become dirty and deteriorate regardless of the level of care; this deterioration will affect comfort and visual acuity; and frequent replacement avoids these negative factors.

Use of hyper-thin, low water content hydrophilic lenses for extended wear.

A study was conducted to determine the efficacy of low water content, hyper-thin lenses for extended wear by myopic patients. Patients selected had from 1 to 7 D of simple myopia or myopia with up to 2 D of astigmatism. Patients were either first time wearers or previously successful soft lens wearers. All patients were fitted with Bausch & Lomb O3 or O4 series lenses and were evaluated for 6 months. Either heat or a chemical disinfection system was used. The study shows that Bausch & Lomb O Series lenses may be used successfully for up to 1 week of continuous wear. Visual acuity, patient comfort, lens life, and physiological tolerance compared favorably with those achieved when the currently available high water content lenses were used for extended wear.

Extended wear hydrogel lenses. Long-term effectiveness and costs.

During the period 1976-79, 1,201 of 1,552 aphakic patients were successfully fitted with third generation extended wear hydrogen lenses of thin-membrane design (CSI¿ lens) and highly hydrated polymer design (Permalens,¿Sauflon¿) without significant or permanent visula loss. Between 79% and 82% of the patients who failed did so in the first 90 days, and thereafter failure rates declined with time. Replacement rates for lenses approximated one lens per eye per year. Rates of required removal for cleaning varied. Ten to 13% of patients required cleaning at less than three-month intervals, and 5-6% at less than one month. For average patients with unilateral devices and no complication, extended wear lenses in Georgia are estimated to cost approximately three times as much as an intraocular lens over a 20-year follow-up period. General advantages ofextended wear third generation lenses include: (1) an acceptably savce and visually effective way to correct aphakia when patients are carefully selected, fitted, educated, and followed; (2) can be easily removeed, refitted or updated as technology advances; and (3) will not replace intraocular lenses, but can be used when implantation is contraindicated and should prevent the need for secondary or bilateral implantation or keratophakia in most cases.

Prolonged wear soft contact lenses.

Of 78 patients eligible for prolonged wear contact lenses, 50 (65%) were successfully fitted and followed for four months to four years. The most serious complication was peripheral corneal ulceration, occurring in 5 (10%) patients. None of these patients suffered permanent visual loss. The fitting of prolonged wear lenses required six or seven office visits during the first year and at least one lens per eye during the first year, for uncomplicated cases. In difficult cases the number of office visits and the number of replacement lenses increased significantly. In terms of the number of office visits and replacement lenses, the soft contact lens compares unfavorably with the intraocular lens. It is our feeling that the prolonged wear soft contact lens should be used when a lens implant is contraindicated or as an alternative to secondary lens implantation.

[Some special indications for wearing contact lenses (author's transl)]. / Spezielle Indikationen zur Kontaktlinsenversorgung.

The typical distinguishing features of special cases which require contact lenses for satisfactory vision are described. Hence in the first case with anisometria associated with irregular astigmatism of one eye, to which a toric soft contact lens was adapted. In the second case a visual acuity of only 0,6 monocular was attained with the best spectacle lens, however with contact lense the visual acuity was 1.25. Here a verdict from a social court is mentioned, which obliged the sickness insurance to take over the costs for such a case. In the third case the adaptation of contact lenses was undertaken after radical bilateral keratoplasty because of parenchymatous keratitis, and an improvement in visual acuity of at least 400% resulted.