Presbyopia correction with multifocal contact lenses: Evaluation of silent reading performance using eye movements analysis

PurposeMany activities of daily living rely on reading, thus is not surprising that complaints from presbyopes originate in reading difficulties rather in visual acuity. Here, the effectiveness of presbyopia correction with multifocal contact lenses (CLs) is evaluated using an eye-fixation based method of silent reading performance.ΜethodsVisual performance of thirty presbyopic volunteers (age: 50 ± 5 yrs) was assessed monocularly and binocularly following 15 days of wear of monthly disposable CLs (AIR OPTIX™ plus HydraGlyde™, Alcon Laboratories) with: (a) single vision (SV) lenses – uncorrected for near (b) aspheric multifocal (MF) CLs. LogMAR acuity was measured with ETDRS charts. Reading performance was evaluated using standard IReST paragraphs displayed on a screen (0.4 logMAR print size at 40 cm distance). Eye movements were monitored with an infrared eyetracker (Eye-Link II, SR Research Ltd). Data analysis included computation of reading speed, fixation duration, fixations per word and percentage of regressions.ResultsAverage reading speed was 250 ± 68 and 235 ± 70 wpm, binocularly and monocularly, with SV CLs, improving statistically significantly to 280 ± 67 (p = 0.002) and 260 ± 59 wpm (p = 0.01), respectively, with MF CLs. Moreover, fixation duration, fixations per word and ex-Gaussian parameter of fixation duration, μ, showed a statistically significant improvement when reading with MF CLs, with fixation duration exhibiting the stronger correlation (r = 0.79, p < 0.001) with improvement in reading speed. The correlation between improvement in VA and reading speed was moderate (r = 0.46, p = 0.016), as was the correlation between VA and any eye fixation parameter.ConclusionAverage silent reading speed in a presbyopic population was found improved with MF compared to SV CL correction and was faster with binocular compared to monocular viewing: this was mainly due to the faster average fixation duration and the lower number of fixations. Evaluating reading performance using eye fixation analysis could offer a reliable outcome of functional vision in presbyopia correction.     

Randomized crossover trial of silicone hydrogel contact lenses

PurposeThe aim of the current study is to assess, using new technologies, the interaction of four monthly silicone hydrogel contact lenses on the ocular surface and the comfort over 15 days of use.MethodsProspective cross-over, randomized and double-masked study including four materials (lotrafilcon-B, samfilcon-A , comfilcon-A and filcom-V3). Clinical examination was performed in the following order: tear meniscus height, first break-up of the tear film, the average time of all tear film breakup incidents, bulbar redness, limbal redness (Keratograph 5M ,Oculus, Germany); central corneal thickness (Pentacam, Oculus, Germany), thermography values (FLIR A325; FLIR Systems Inc., USA), and slit-lamp evaluations, including ocular surface staining. Finally, subjective comfort was obtained from Contact Lens Dry Eye Questionnaire-8.ResultsThe impact of contact lens wear on the ocular surface didn’t show statistically significant changes over time except for corneal and conjunctival staining grades on day 15 compared to day 1 for the comfilcon A group (P = .003 and P = .01, respectively). Contact lens stability and impact on the ocular surface during contact lens wear didn’t show statistically significant changes over time except in the case of the comfilcon A material with respect to the irritation item (P = .01).ConclusionsThese results suggest that the impact of monthly silicone hydrogel contact lens materials on the ocular surface after and during contact lens wear, contact lens stability over time, and subjective comfort did not reveal any significant changes over 15 days of use for any of the materials.     

The effect of concentric and aspheric multifocal soft contact lenses on binocular vision in young adult myopes

PurposeMultifocal soft contact lenses (MFCLs) are prescribed to inhibit myopia progression; these include aspheric and concentric designs. The effects of MFCLs on visual quality, accommodation and vergence in young-adult myopes were evaluated.MethodsParticipants were twenty-six myopes (19–25 years, spherical equivalent ?0.50 to ?5.75D), with normal binocular vision and no past myopia control. Pupil sizes were 4.4 ± 0.9 mm during distance viewing and 3.7 ± 0.8 mm at near. In random order, participants wore four MFCLs: Proclear single vision distance, MiSight concentric dual focus (+2.00D), distance center aspheric (Biofinity, +2.50D) (CooperVision lenses), and NaturalVue aspheric (Visioneering Technologies). Testing included visual acuity, contrast sensitivity (Pelli-Robson), stereoacuity, accommodation response, negative and positive relative accommodation, horizontal phorias, horizontal fusional vergence and AC/A ratio, and a visual quality questionnaire.ResultsThe four lenses differed in distance (p = 0.001) and near visual acuity (p = 0.011), and contrast sensitivity (p = 0.001). Compared with the single vision lens, the Biofinity aspheric had the greatest visual impact: 0.19 ± 0.14 logMAR distance acuity reduction, 0.22 ± 0.15 log contrast sensitivity reduction. Near acuity was affected less than distance acuity; the reduction was greatest with the NaturalVue (0.05 ± 0.07 logMAR reduction). The MFCLs altered the autorefraction measure at distance and near (p = 0.001); the accommodation response was less with aspheric lenses. Negative relative accommodation reduced with the aspheric lenses (p = 0.001): by 0.9 ± 0.5D with Biofinity and 0.5 ± 0.7D with NaturalVue. Exophoric shifts were greater with aspheric lenses (1.8 ± 2.4Δ Biofinity, 1.7 ± 1.7Δ NaturalVue) than with the concentric MiSight (0.5 ± 1.3Δ).ConclusionsMFCLs alter visual performance, refraction and vergence; two aspheric lenses had greater effect than a concentric lens.     

Enhancing the approach to selecting eyewear (EASE): A multi-centre, practice-based study into the effect of applying contact lenses prior to spectacle dispensing

Purpose

To examine the impact of contact lens application in non-contact lens wearers prior to spectacle dispensing.

Methods

Ninety-one eligible subjects with no previous contact lens experience were randomly assigned into either a test group (52 subjects) or control group (39 subjects). The former group was offered contact lenses before spectacle dispensing. The latter group proceeded to spectacle dispensing in the normal way without being offered contact lenses. The response to the offer of contact lenses, fit success, the impact on the spectacle dispensing process and the longer term purchase of contact lenses were measured and compared for the test and control groups.

Results

Of the test group, 46 (88%) agreed to try contact lenses. All subjects were suitable for contact lenses after a slit lamp examination and lenses were successfully fitted to 45 of the 46 subjects (98%). The test group reported a superior subjective spectacle dispensing experience and spent £267 ± 143 (mean ± standard deviation) on their spectacle frames and lenses, 32% more than the control group (£202 ± 128). At 3 months post dispensing, 17 test patients (33% of original cohort) had purchased contact lenses compared with five control subjects (13%) (p = 0.001).

Conclusions

The opportunity to try contact lenses prior to spectacle dispensing was well received by subjects who generally reported a very positive experience. In particular, contact lenses assisted in seeing frame detail and suitability for wear. One third of subjects proceeded to purchase contact lenses. We recommend that practitioners consider offering contact lenses to all suitable patients who are proceeding to spectacle dispensing to optimise the dispensing process and to provide an opportunity to try contact lenses.     

Exploring contact lens opportunities for patients above the age of 40 years

PurposeContact lenses offer a good option for patients with presbyopia, especially with improved optical designs available in modern multifocal contact lenses. Due to the ageing population there is good opportunity to increase contact lens penetration by managing these patients better. However, multifocal contact lenses achieve low penetration in the market.MethodsA questionnaire was administered to people aged above 40 years, to investigate their perceptions of contact lenses for presbyopia. Only people, with presbyopia, who were existing contact lens wearers or willing to try contact lenses were included. Participants were recruited from United Kingdom (UK), United States of America (USA), Netherlands, Germany, France, Spain and Italy.ResultsData from 1540 participants above the age of 40 years was collected, 57.9% were females and 42.1% males. Overall, 50.8% of the participants wore contact lenses, but contact lens wear was less common amongst older participants. Some data supported earlier studies, such as 6.1% wore gas permeable lenses. However, only 25% of the contact lens wearers used multifocal contact lenses. The reasons the participants wanted to wear contact lenses were similar to younger patient such as sports or cosmesis reasons. Reasons why participants had dropped out of contact lenses included discomfort and dry eye related issues. Poor visual performance with contact lenses was a reason to dropout of contact lenses for the older participants.ConclusionsThe study highlights some failings by eye care practitioners in the management of patients with presbyopia. It seems that patients of this age group are seeking suggestions and recommendations from their eye care practitioner including upgrading contact lenses and dual wear options. The day-to-day problems encountered by the contact lens wearers in this study seem to be, in the main, things that could be easily tackled by additional counselling and instruction from the eye care practitioners.     

Accuracy,inter-observer and intra-observer reliability in topography assessment of multifocal contact lens centration

PurposeTo evaluate the accuracy and reliability (inter and intra-observer) of a method to assess multifocal contact lenses (MCLs) centration using a corneal topography unit.MethodDaily-disposable MCLs (Fusion 1 day Presbyo) were fitted on both eyes of the subjects. For each lens fit a slit lamp digital picture and videokeratograph image were taken in a rapid but randomised sequence. Photo-editing software was used to assess the position of the MCL centre with respect to pupil centre as taken from the slit lamp photograph. The position of the MCL centre was automatically detected as the point of maximum curvature from the videokeratography. Three further manual and qualitative procedures to detect MCL centre, comparing a template of CLs optic zones to the videokeratographic image were performed by 4 practitioners using 3 different algorithms to represent the topographic map. Each manual reading was repeated 3 times.ResultsTwenty-two subjects (11 males) aged 22.8 ± 1.9 years (range 20.8–27.0 years) were recruited. The accuracy of the 4 topographic assessments in determining the centre coordinates of the MCL with respect to SL assessment was good: no differences were found in the left eyes and although in the right eyes a more temporal and superior position of MCLs was determined (paired t-test, p < 0.05) the difference was clinically negligible (0.16 ± 0.36 mm horizontally, 0.23 ± 0.48 vertically). Amongst the 4 practitioners one-way Anova for repeated measures showed no differences for any of the 3 manual assessments. Intra-class correlation coefficient was calculated among the 3 readings for each manual procedure and was very good (between 0.75 and 0.98) in 3 practitioners and moderate (between 0.49 and 0.92) in the fourth.ConclusionsThe assessment of MCL centration by performing corneal topography over the MCL is an accurate method. Furthermore, inter and intra-practitioner reliability showed by manual procedures appeared very good.     

Impact of soft contact lenses on lid- parallel conjunctival folds

PurposeLid-parallel conjunctival folds (LIPCOF) are related to dry eye symptoms and appear to be related to mechanical forces in blinks. The primary aim of this longitudinal, parallel group study was to investigate impact of contact lens wear (CLW) on LIPCOF and secondly the impact of contact lens wear on lid-wiper epitheliopathy (LWE) and dry eye symptoms.MethodsAfter a 2-week wash-out phase with a hydrogen peroxide care regimen, 30 experienced contact lens wearers (female: 25, male: 5; median age: 34.5 years) with at least LIPCOF Sum grade 1 (nasal + temporal LIPCOF, either eye) were randomised into three groups: one which discontinued CLW (SPEC), one which were refitted with senofilcon A two-weekly replacement daily wear silicone hydrogel (OAS) and one which continued to wear their habitual lenses (HCL). LIPCOF Sum and LWE were evaluated at the enrolment visit and over a period of 12 weeks. LIPCOF were classified by fold number using a four-grade scale. LWE was classified using a five-point scale after staining with lissamine green and fluorescein. Symptoms were evaluated with the Ocular Surface Disease Index (OSDI).ResultsOn enrolment, there were no differences between groups for LIPCOF Sum (median 2.0), LWE (1.0) and OSDI scores (12.5) (Kruskal-Wallis, p > 0.718). Median changes at 12-weeks follow-up compared to the enrolment visit were (HCL-group: 0.5, 0.0, 0.0; OAS-group: −1.0, −0.5, −10.42; SPEC-group: −0.5, −0.5, −5.21; LIPCOF, LWE and OSDI, respectively). LIPCOF (Friedman-Test, p = 0.178), LWE (p = 0.791) and OSDI (p = 0.874) were unaltered over the period of observation in the HCL group. LWE (p = 0.120) was unaltered in OAS group but LIPCOF (p = 0.001) and OSDI (p = 0.003) significantly improved. In the SPEC group LIPCOF (p = 0.031), LWE (p = 0.002) and OSDI (ANOVA repeated measurements, p = 0.034) changed significantly.ConclusionsRefitting experienced CLW with senofilcon A daily wear, 2-week reusable contact lenses, or ceasing lens wear, improved LIPCOF, LWE and dryness symptoms.     

Zeta potential of tear samples: A tool to explore the effects of wear of contact lenses

PurposeThe aim was to develop a method to assess the electrostatic properties of human tear samples, and to evaluate their modifications induced by the wear of contact lenses (CLs).MethodThe barrier method was developed for the measurement of the isoelectric point (IEP) on relatively small quantities. The method was applied to compare three groups: tears (T_NW) of non-wearers, tears (T_{W_etaf}) of regular wearers of etafilcon A CLs, and tears (T_{W_omaf}) of regular wearers of omafilcon A CLs. Zeta potential (ζ) as a function of pH was measured by a Zetasizer Nano ZS90 (Malvern Instruments) on 40%-diluted samples, obtained by mixing 57 μL of tears of different subjects of the same group with 85 μL of HCl aqueous solution. IEP was deduced as the pH at which ζ is zero, i.e. the net electric charge on tear constituents being neutralized.ResultsWithin an error of about 0.05, IEPs were found to be 2.90 (T_NW), 2.80 (T_{W_omaf}), and 3.16 (T_{W_etaf}). On average, a lower H⁺ concentration is needed to neutralize the surface charge of the tear components of etafilcon A wearers, compared to both T_NW and T_{W_omaf}.ConclusionIEP measurements on tear samples of wearers of different types of CLs are proposed in order to enhance the knowledge on the modifications of the profile of charged species in tears. The T_{W_etaf} results, compared to those of the other groups, are compatible with an increase, due to the wear of etafilcon A CLs, of the relative concentration of high-IEP proteins.     

In vitro analysis of the interaction of tear film inflammatory markers with contemporary contact lens materials

PurposeSeveral clinical studies have suggested that reusable silicone hydrogel contact lens materials exhibit a two-times increased rate of corneal infiltrative events compared to reusable hydrogels. One potential factor contributing to this complication relates to the differential uptake of tear film-based pro-inflammatory cytokines. The purpose of this study was to use an in vitro assay to investigate whether four pro-inflammatory cytokines differed in their uptake onto six contemporary contact lens materials.MethodsConventional hydrogel (etafilcon A, omafilcon A) and silicone hydrogel (balafilcon A, comfilcon A, senofilcon A, somofilcon A) contact lens materials were soaked in solutions containing pro-inflammatory cytokines IL-1β, IL-6, IL-8 and TNF-α. Samples of the soaking solutions were collected over various time points and analyzed using the Meso Scale Discovery system, which served as a measurement of cytokine uptake onto the contact lens materials.ResultsBoth conventional hydrogels (etafilcon A, omafilcon A) and two of the four silicone hydrogels tested (balafilcon A, comfilcon A), exhibited some uptake of IL-1β, IL-8 or TNF-α (p < 0.05). Senofilcon A and somofilcon A did not exhibit uptake of any of these cytokines (p > 0.05). There was no uptake of IL-6 onto any of the contact lens materials investigated (p > 0.05).ConclusionThe contact lens materials tested did not exhibit any uptake of IL-6 and furthermore, did not exhibit more than 10 ± 3 % to 25 ± 12 % uptake of IL-1β, IL-8 or TNF-α. Numerous factors could contribute to the reported increase in corneal infiltrative events with reusable silicone hydrogel materials, however, based on these results, it appears that uptake of these four cytokines are unlikely to contribute to this finding.     

Ten years of disposable contact lenses - a review of benefits and risks

The performance and benefits as well as the risks and complications of disposable soft lenses (single use disposable or re-used 2-4 weeks) are reviewed in relation to corneal physiology. Modern designs and advanced technology have resulted in disposable lenses providing excellent visual performance. Fewer subjective symptoms (e.g. dryness and grittiness), slit-lamp findings (such as injection and tarsal abnormalities), and inflammatory responses (papillary conjunctivitis; contact lens-induced acute red eye) have been reported with disposable lenses than with conventional soft lenses. The risk of contact lens-induced keratitis (CLIK) has been reported to be higher for daily wear of disposable lenses than for other lens types by UK investigators. Other studies have shown the risk of CLIK with disposable lenses to be equal to that with conventional soft lenses, and in two extensive Swedish studies, the incidence of severe keratitis was found to be significantly lower for daily wear (DW) of disposable lenses than for DW of conventional soft and rigid gas permeable lenses. Both the total complication rate and the number of unscheduled visits are found to be significantly lower for disposable lenses than for conventional soft lenses in several studies. Comfort has been reported to be significantly better and overall satisfaction significantly greater with disposable lenses than with conventional soft lenses according to many studies. These may be important reasons why the success rate for disposable lens wear is reported to be fairly high, generally 70-90%. The importance of appropriate care for 're-usable disposable lenses' must be stressed. One day disposable lenses, if used as directed, will eliminate the risk factors of inadequate cleaning and disinfection as well as contaminated lens cases.     

Characterization of patients who report compliant and non-compliant overnight wear of soft contact lenses

Purpose

To describe compliant and non-compliant overnight wear (EW) of soft contact lenses from a large observational study.

Methods

A retrospective chart review of 3211 SCL patients with known EW status (aged 8–33 yrs, SCL power +8.00 to −12.00 D) captured data from 10,516 clinical visits (2006–2009). Status of EW was either daily wear (DW), compliant EW (overnight wear of US Food & Drug Administration (US FDA) EW-approved lenses), non-compliant EW (overnight wear of DW-approved lenses). The effect of demographic and clinical characteristics on the likelihood of reporting EW was examined using logistic regression. Additionally, the effect of these same characteristics on the likelihood of non-compliant EW was assessed with logistic models.

Results

Eight-hundred and eight patients (25.2%) reported EW. Non-compliant EW was reported by 6% of wearers (13 hydrogel, 2 silicone hydrogel brands) In multivariate models, patient age and lens replacement schedule were significant factors for EW (vs. DW) and for non-compliant (vs. compliant) EW (p < 0.0001). Other factors significantly related to EW were gender, smoking, lens material, sphere power, and years of CL wear (p ≤ 0.007, all).

Conclusions

Young people (ages 18–25 yrs), males, smokers, myopes, silicone hydrogel lens wearers and patients with >1 yr of CL wear were significantly more likely to report EW. Non-compliant EW occurred often in young people and daily disposable wearers, though many brands had non-compliant EW use. Understanding who is likely to wear EW and non-compliant EW will help clinicians pointedly counsel patients more at risk on best practices with EW.     

Patients’ and prescribers’ perception of contact lenses as a potential ocular drug delivery system

Contact lenses (CLs) designed to deliver medication gradually to the eye are being developed and investigated for the use in ocular drug delivery. The aim of the current research is to determine patients’ acceptance of the use of lenses for ocular drug delivery. In addition, the study aimed to seek the views and perceptions of healthcare professionals (HCPs) on CLs as a method of ocular drug delivery and whether it will be prescribed to treat ocular conditions.This was a cross-sectional survey targeted at patients and HCPs. Two separate questionnaires were created with open-closed ended and multiple response questions, gauging the perceptions and acceptance of CLs as drug delivery tool. The patients’ survey was distributed in John Radcliffe (JR), Oxford and Moorfields eye hospital (MEH), London, UK. The HCPs’ questionnaire was manually distributed and was also devised on Survey Monkey and sent by email to ophthalmologists, optometrists, opticians, GPs and hospital and community pharmacists. The data were analysed using SPSS statistical software and Excel.Over 60% (92/151) of patients would accept the use of CLs for their ocular treatment with the highest acceptance being reported by patients in the age group of 30–49 years old. The most frequently used conventional treatment formulation was eye drops as indicated by 87% (131/151) of the responses. More than half of eye drop users (57%, 75/131) indicated that they would accept using CLs expecting them to reduce the frequency of application of the medicine and be less time consuming. Interestingly, half of HCPs were not aware of CLs as an ocular drug delivery method; nevertheless, a total of 65 HCPs out of the 112 surveyed stated that they would prescribe/dispense CLs to treat ocular disease.     

Performance evaluation of delefilcon a water gradient daily disposable contact lenses in first-time contact lens wearers

Purpose

To evaluate the tolerability of and subject and investigator satisfaction with delefilcon A (DAILIES TOTAL1^®) daily disposable contact lenses in first-time contact lens wearers.

Discrimination of subjective responses between contact lenses with a novel questionnaire

Purpose

To describe a ranked symptoms scale (RSS) discriminating subjective responses in contact lens (CL) wear in various situations.

Patterns of prescribing extended wear contact lenses

Patterns of prescribing extended wear contact lenses in the UK were determined by mining through data gathered from annual contact lens fitting surveys conducted over the past 12 years. The increased rate of extended wear prescribing this century - which in 2007 had reached 7% and 19% of all soft lens new fits and refits, respectively - probably reflects the superior clinical performance of silicone hydrogel lenses for this purpose.     

International survey of contact lens fitting for myopia control in children

PurposeTo determine the extent of contact lens fitting for myopia control (MC) in children (defined as ≤ 17 years of age) worldwide and to characterize the associated demographics and fitting patterns.MethodsSurvey forms were sent to contact lens fitters in 66 countries between January and March every year for eight consecutive years (2011–2018, inclusive). Practitioners were asked to record data relating to the first 10 contact lens fits performed after receiving the survey form. Data were analysed for those countries reporting ≥ 100 contact lens fits to children.ResultsData were analysed for 535 MC fits and 23,295 other (non-MC) lens fits undertaken in 31 countries reporting ≥ 100 contact lens fits to children, with 52.1% of MC fits and 12.0% of non-MC fits being with rigid lenses (p < 0.0001). Overall, MC lenses represented 2.3% of all contact lens fits to children, with significant differences between nations (p < 0.0001), ranging from no MC fits recorded in the Czech Republic, Greece, Japan, South Korea and Puerto Rico, to 24.9% in Austria. There has been an increase in contact lens fitting for MC over the survey period (p < 0.0001). MC contact lenses were fitted to younger children compared to non-MC lenses (MC, median 13 years vs. non-MC, median 15 years) (p < 0.0001). There was no sex bias in the fitting of MC lenses (p = 0.89).ConclusionsMC lenses are currently being prescribed for younger children in equal measure in terms of soft vs. rigid lenses and males vs. females. The extent of MC fitting is low and varies between nations. The gradual increase in MC fitting throughout the survey period perhaps reflects growing concerns among practitioners over the myopia epidemic.     

Comparison of the influence of corneo-scleral and scleral lenses on ocular surface and tear film metrics in a presbyopic population

Purpose

To assess and compare the effect of the corneo-scleral lenses (C-ScL) and scleral lenses (ScL) on tear film parameters and central corneal thickness (CCT) in healthy presbyopic subjects.

Novel silicone elastomer contact lenses designed for simultaneous viewing of distance and near eye displays

SignificanceAs technology advances, there is a need for a safe and well-fitting contact lens that can be utilized to carry embedded components without concerns of decreasing oxygen permeability to the eye.PurposeThe purpose of this study was to assess fitting characteristics, vision and performance of a novel ultra-high Dk silicone elastomer contact lens having a fully encapsulated two-state polarizing filter and a high-powered central lenslet that allows viewing at distance and viewing of a near eye display, while managing the concomitant high water vapor permeability of the material.Methods15 participants were fit with the silicone elastomer study lenses. Biomicroscopy was conducted before and after lens wear. Visual acuity with manifest refraction and visual acuity with an over-refraction while wearing the plano-powered study lenses were measured. Participants wore spectacles with micro-displays at the focal length of the lenslet on each eye. Lens fit was assessed including ease of lens removal. Subjective assessments of viewing the micro-displays were completed on a 1(unable) to 10(immediate/profound/stable) scale.ResultsBiomicroscopy revealed no eyes had moderate or severe corneal staining after study lens wear. Mean (±standard deviation) LogMAR acuity for all eyes was −0.13(0.08) with best corrected refraction and −0.03(0.06) with the study lenses and over-refraction. Mean spherical equivalent of the manifest refraction for both eyes was −3.12 D and was −2.75 D over the plano study lenses. Subjective assessments revealed a mean score of 7.67(1.91) for ease of obtaining fusion; 8.47(1.30) for ease of observing three-dimensional vision, and 8.27(1.49) for stability of the fused binocular display vision.ConclusionThe silicone elastomer study lenses with a two-state polarizing filter and central lenslet allow for vision at distance and on spectacle mounted micro-displays.     

Trends in the use of silicone hydrogel contact lenses for daily wear

Although the first silicone hydrogel contact lenses introduced onto the world contact lens market in 1999 held approval for both daily wear and extended wear use, the latter modality was promoted much more heavily by the manufacturers. The first silicone hydrogel lenses specifically promoted for daily wear were introduced in 2003. Data that we have gathered from annual contact lens fitting surveys demonstrate an immediate increase in market share whereby this lens type now represents more than one-third of soft lens fits in the United Kingdom. The success of this lens category is attributed to the health and safety benefits of silicone hydrogel materials and the positive impact of lens manufacturers by way of the effective marketing and distribution of these products.     

Purchase of contact lenses and contact-lenses-related symptoms following the Contact Lenses in Pediatrics (CLIP) Study

Background

The rate and reasons for discontinuation of contact lens wear by young patients are not well known. The Contact Lenses in Pediatrics (CLIP) Study surveyed participants 3 months after the final study visit to determine the percentage of participants who continued to wear contact lenses after study conclusion. The factors associated with continued contact lens wear and differences in behaviors between the children and teens were also determined to provide insights to practitioners who provide refractive correction for patients in those age groups.

Methods

Three months after the CLIP Study completion, participants and parents returned mailed surveys that assessed post-study lens purchase and symptoms related to contact lens wear if contact lenses wear had been continued. Responses were compared between the children and teens using χ² or Fisher's exact test.

Results

Almost 92% of the surveys were returned. Eighty percent of teens’ parents reported purchasing lenses after the study, vs. 63% of the children's parents (p = 0.02). Symptoms reported at the last study visit were not significantly associated with future purchase, though there was a trend towards more light sensitivity in those who did not purchase more contact lenses (23.1% vs. 11.8%). Satisfaction with contact lenses was high among both those purchasing additional contact lenses and those who did not. Both children and teens reported similar frequencies of symptoms such as burning, itching or tearing eyes 3 months following study completion. Teens reported having contact-lens-related dry eyes more frequently than children.

Conclusions

A large proportion of children and an even higher proportion of teens continued wearing their lenses 3 months after completing the CLIP Study. Children and teens reported similar contact lens comfort and low frequencies of most symptoms, though teens experienced more dry-eye symptoms. Overall, reports of symptoms in this sample were lower than had been reported in adult populations by other investigators.