Graeme Young

A multi‐centre study of lapsed contact lens wearers

Purpose:  Discontinuation from contact lens wear has been identified as a contributing factor in the lack of growth of contact lens use in Europe. The purpose of this study was to determine the proportion of lapsed contact lens wearers that can be refitted successfully with contact lenses and to evaluate the reasons for discontinuation from contact lens wear.

Prevalence of Ocular Surface Symptoms, Signs, and Uncomfortable Hours of Wear in Contact Lens Wearers: The Effect of Refitting with Daily-Wear Silicone Hydrogel Lenses (Senofilcon A)

Purpose. Many soft contact lens wearers have symptoms or signs that compromise successful lens wear. This study estimated the prevalence of problems in current wearers of soft contact lenses and tested the effect of refitting patients with senofilcon A silicone hydrogel lenses (ACUVUE Oasys). Methods. Prevalence was estimated from 1,092 current lens wearers for frequent or constant discomfort or dryness, at least 2 hours of uncomfortable wear, at least grade 2 limbal or bulbar hyperemia (0–4), or at least grade 3 corneal staining (0–15). In the second part of the study, 112 of the 564 wearers classified as problem patients were refitted with senofilcon A lenses and reassessed 2 weeks later. Results. Fifty-two percent (564 of 1,092) had some qualifying criteria, with dryness reported by 23%, discomfort by 13%, and at least 2 hours of uncomfortable wear by 27%. Six percent of subjects had qualifying limbal hyperemia; 10% had bulbar hyperemia; and 12% had corneal staining. After refitting 112 problem patients, 75% had less dryness; 88% had better comfort (P<0.0001 each); and 76% had fewer uncomfortable hours of wear (P=0.004). Although the average wearing time was unchanged, comfortable wearing time increased significantly (10.4 to 11.6 hours) (P=0.004). All (35 of 35) eyes with qualifying limbal hyperemia before the refit also improved (P<0.0001), as did 80% (40 of 50) of those with bulbar hyperemia (P<0.0001) and 76% (26 of 34) of those with corneal staining (P=0.005). Conclusions. Most soft lens wearers encounter clinically significant signs or symptoms with their current contact lenses. Refitting with new-generation silicone hydrogel lenses (senofilcon A) can alleviate some of these common problems.

Characteristics of the pre‐lens tear film during hydrogel contact lens wear

The integrity of the pre‐lens tear film I PLTF) is an important determinant of the clinical performance of contact lenses. The PLTF of eight hydrogel lenses, ranging from 36.5% to 85% water content, was assessed on six asymptomatic lens wearers in a randomized, double‐masked experiment. Using a specular reflection technique, the thicknesses of the lipid and aqueous phases were found to be greater on lenses of higher water content. Water content was measured before and after 90 min wear using a hand‐held refractometer. Non‐invasive tear break‐up lime was also found to be greater for higher water content lenses. No association was found between lens dehydration and PLTF characteristics. The differences in PLTF noted in this study may help to explain the differences noted between some lenses in their rates of surface deposition.

The TFOS International Workshop on Contact Lens Discomfort: Report of the Contact Lens Materials, Design, and Care Subcommittee

Jones, L., Brennan, N. A., Gonzalez-Meijome, J., Lally, J., Maldonado-Codina, C., Schmidt, T. A., … Nichols, J. J. (2013). The TFOS International Workshop on Contact Lens Discomfort: Report of the Contact Lens Materials, Design, and Care Subcommittee. Investigative Opthalmology & Visual Science, 54(11), TFOS37. https://doi.org/10.1167/iovs.13-13215

Subjective and objective measures of corneal staining related to multipurpose care systems.

An objective, digital-imaging method of measuring corneal staining was evaluated in 24 subjects wearing soft contact lenses. The method was used to compare the clinical performance of common multipurpose care systems (MPS) for soft contact lens care. Subjects used three different MPS, one containing polyquaternium-1 (PQ) and two containing polyhexanide (PX1 and PX2), for 2 weeks in a randomised, single-masked (investigator) crossover study. Corneal staining induced with the three MPS was analysed using an image-processing program (ImageTool, UTHSCSA Version 2, University of Texas, USA). Conjunctival hyperaemia and papillae were also evaluated. The intraclass correlation coefficient was similar with image analysis to that of investigator grading (0.876, 0.879, respectively). Significant differences in staining response were detected using the objective method. There was significantly less staining area with polyquaternium-1 (PQ) than polyhexanide (PQ: 0.12 mm(2), PX2: 0.91 mm(2)). Inferior palpebral papillae were significantly greater with PX2 than with PQ (1.0, 0.7 (0-4), respectively). The technique was shown to be an effective method of evaluating different corneal staining responses. Bilateral corneal staining in three or more quadrants is useful in the diagnosis of MPS-related staining.

Soft contact lens-related dryness with and without clinical signs.

Purpose. To report demographics, wearing patterns, and symptoms from soft contact lens (SCL) wearers with significant SCL-related dryness symptoms with and without significant ocular signs of dryness. Methods. In a multicenter, prospective observational clinical trial, symptomatic SCL wearers reported significant SCL-related dryness via self-administered questionnaire of frequency and intensity of dryness after a dry eye (DE) examination. DE etiology was assigned post hoc by an expert panel, and those with and without significant DE-related signs were analyzed by univariate logistic regression. Possible DE etiologies were aqueous tear deficiency, SCL-induced tear instability, meibomian gland dysfunction, or “other.” Wearers without signs that qualified for any DE etiology were designated as No DE Signs (NDES). Results. Of the 226 SCL symptomatic wearers examined, 23% were without signs, 30% had aqueous tear deficiency, 25% had SCL-induced tear instability, 14% had meibomian gland dysfunction, and 8% had “other” diagnoses. The NDES wearers had significantly longer pre-lens break-up time (9.8 vs. 6.6 s, p < 0.0001), better lens wetting (3.4 vs. 2.4 0 to 4 scale, p < 0.0001), lower levels of film deposits on lenses (0.45 vs. 0.92, 0 to 4 scale, p < 0.0001), and of most slit lamp signs. The NDES wearers were significantly more likely to be male (36% vs.19%, p = 0.013), were less likely to have deteriorating comfort during the day (81% vs. 97%, p = 0.001), reported longer average hours of comfortable wear (11 ± 3 vs. 9 ± 4 h, p = 0.014), had older contact lenses (18 ± 14 vs. 13 ± 12 days, p = 0.029), and greater intensity of photophobia early and late in the day (p = 0.043 and 0.021). Conclusions. Symptoms of dryness in SCL wearers stem from a variety of underlying causes. However, nearly one-quarter of these symptomatic SCL wearers appear to be free of signs of dryness. The effective management of CL-related dryness requires a comprehensive range of clinical assessments and the use of a diverse range of management strategies.

Clinical Evaluation of Long-Term Users of Two Contact Lens Care Preservative Systems

Purpose: To clinically evaluate long-term users of two different contact lens care preservative systems and to investigate whether prolonged use is associated with an increase in the prevalence of dry eye. Methods: Eighty-nine wearers of group IV hydrogel or silicone hydrogel lenses participated in this one-visit, investigator-masked study. Subjects were required to have consistently used a polyhexamethylene biguanide (PHMB) or polyquaternium-1 (PQT) based solution for 2 years. Consistent use was defined as 80% for the past 2 years and 100% for the past year. Clinical assessments included: average and comfortable wear time; overall and end-of-day comfort; signs of dryness, discomfort, burning or stinging, grittiness or scratchiness and visual changes; non-invasive and fluorescein break-up-time; pre-ocular tear film lipids, tear meniscus height, Schirmer and fluorescein clearance tests; limbal and bulbar hyperemia; palpebral roughness; corneal and conjunctival staining; lens front surface wetting; and lens film deposits. Results: Significantly more grittiness or scratchiness was reported by subjects using a PHMB-containing system (67% vs. 44%; P = 0.02). Palpebral roughness and hyperemia were significantly greater in the PHMB group wearing group IV lenses (P = 0.01 and P = 0.05, respectively). Corneal staining was significantly higher in the PHMB users in all four peripheral sectors (P < 0.01). Nasal and temporal conjunctival staining was also significantly higher for users of PHMB-containing systems (P < 0.05). Front surface lens wettability was significantly better for group IV PQT users compared to PHMB users (P = 0.008), with 84% vs. 72%, respectively, with lenses graded by the investigator as having “good” or “excellent” wettability. Significantly higher levels of lens front surface film deposits were noted with PHMB users (P = 0.007), with 58% of group IV lenses treated with PHMB compared with 38% of group IV lenses treated with PQT showing some lens front surface film deposition. No significant differences between the two preservative system groups were noted for the range of dry eye evaluations nor the remaining clinical assessments. Conclusions: Differences in both ocular and lens characteristic were observed between long-term users of two preservative systems used in many contact lens multi-purpose solutions. The findings from this study did not support the hypothesis that prolonged use of PHMB-containing solutions leads to dry eye. Additional studies including a larger sample size and perhaps longer use of the systems could help to further elucidate differences in clinical performance between systems.

Hydrogel lens comfort in challenging environments and the effect of refitting with silicone hydrogel lenses.

Purpose. The purpose of this analysis was to measure the proportion of soft contact lens wearers who wear lenses in challenging environments and to evaluate their resulting comfort in those conditions. A second objective was to determine whether refitting with silicone hydrogel lenses affects lens comfort among subjects who wear lenses in these environments. Methods. Baseline data were collected from 496 hydrogel soft lens wearers on the frequency of use of contact lenses and the associated comfort in 12 challenging environments. Subjects were then refit into second generation silicone hydrogel lenses: senofilcon A (n = 228), galyfilcon A (n = 132), or lotrafilcon B (n = 136). Comfort responses were compared for subjects who “always” or “frequently” used lenses in the queried environments after 2 weeks of silicone hydrogel daily lens wear. Results. More than 80% of subjects used habitual lenses “always” or “frequently” while reading, sitting in an air-conditioned or heated car, using a computer and while driving at night. Less than 40% used lenses “always” or “frequently” while riding in an airplane, at high altitudes, or while napping or sleeping. The least comfortable environments were in dusty, polluted or smoky environments (30% comfortable), and the most comfortable were while reading and using a computer. After 2 weeks use of senofilcon A and galyfilcon A lenses, comfort in all environments improved significantly (Wilcoxon signed rank) except for using a computer with galyfilcon A. After 2 weeks with lotrafilcon B lenses, there was improved comfort while using lenses in all environments except driving at night, using a computer and sitting in an air-conditioned or heated car (p < 0.04, Wilcoxon signed rank). Conclusions. Daily wear contact lens wearers limit use of lenses during air travel or while napping. Use of daily wear silicone hydrogel lenses improved comfort significantly in most environments, allowing subjects to wear them in challenging environments.

Clinical evaluation of factors influencing toric soft contact lens fit.

Purpose. Some knowledge of the orientation position of toric soft lenses is required as part of the fitting process. Although it is known that factors such as lid anatomy, lens design, and fit are important, there is little detailed understanding of how these relate to toric lens orientation. The purpose of this study was to evaluate various patient and lens factors that might influence toric soft lens fit and to determine the predictor variables for lens orientation. Methods. This was a clinical study in which 45 subjects were fitted with a prism-stabilized, mid-water, cast-molded, back surface toric soft lens. The lens was representative of commonly used designs for frequent replacement toric soft lenses. Patient and lens fit variables were assessed, including a range of lid topography features, which were measured using a digital photographic technique. Results. The main patient factors associated with lens orientation and stability were degree of myopia, palpebral aperture, and several angles relating to lid anatomy. Greater upward incline of the temporal lids was associated with increasing inferior-temporal lens orientation; lower myopia and smaller palpebral aperture size were associated with more stable lens orientation. The principal lens fit characteristics affecting lens orientation were postblink movement and lens tightness. Less movement was associated with more stable lens orientation, and increased tightness was associated with slower reorientation speed. Weaker but significant correlations were also shown between a number of other patient and lens variables. Conclusions. A number of patient factors and lens fit characteristics influencing toric soft lens orientation were identified. The findings fall short of allowing practitioners to accurately predict toric lens orientation; however, they do provide some factors to consider when fitting toric soft lenses.

Comparative evaluation of Asian and white ocular topography.

Purpose To provide comparative ocular topography data from a substantial population of East Asian and white eyes. Methods This study evaluated 675 subjects from three ethnic groups: white (n = 255), Chinese (n = 299), and Japanese (n = 121) at investigational sites in four locations: Wenzhou, China; Melbourne, Australia; Tokyo, Japan; and Jacksonville, USA. Subjects underwent the same measurements of ocular topography using identical equipment and protocols. A videokeratoscope (Medmont E300) was used to measure apical corneal radius, simulated K-reading (K), corneal shape factor (CSF), and corneal sagittal height at 10 mm in the two principal meridians. Digital photography was also used to measure ocular parameters including horizontal visible iris diameter (HVID), vertical palpebral aperture (PA), the intercanthal angle (ICA), and upper and lower lid angles. Results Mean HVID measurements were significantly smaller for the Chinese and Japanese groups than whites: 11.26, 11.10, and 11.75 mm, respectively. Horizontal K was significantly steeper for the white than the Chinese and Japanese groups: 7.79, 7.86, and 7.92 mm, respectively. The Chinese eyes showed significantly higher mean vertical CSF (i.e., more prolate) than the other two groups. The Chinese group had significantly narrower PA and steeper ICA than the other two groups: the mean PA and ICA values were 9.71, 10.31, and 10.58 mm and 7.56, 6.32, and 6.27 degrees, for the Chinese, Japanese, and white groups, respectively. One-third of the Chinese (32%) and 31% of the Japanese subjects showed no apparent supratarsal fold (“single eyelid”). There were also significant differences between groups for corneal sagittal height at 10 mm and upper and lower lid angles, but no significant differences for vertical K and horizontal CSF. Conclusions This study has highlighted some differences in ocular topography between Chinese, Japanese, and white ethnic groups that may be relevant to soft contact lens fit.