Daniel Tilia

Comparison of ocular comfort, vision, and SICS during silicone hydrogel contact lens daily wear.

Objectives: The aim of this study was to investigate the relationship between solution-induced corneal staining (SICS) and silicone hydrogel contact lens comfort and vision. Methods: A retrospective analysis of a series of open-label studies were conducted with 24 groups of approximately 40 participants, each wearing 1 of 6 silicone hydrogel contact lenses with 1 of 4 lens care products bilaterally for 3 months of daily wear. The presence of SICS and subjective ocular ratings were collected at 2 weeks and at 1 and 3 months. Results: A total of 1,051 participants were enrolled. The participants with SICS rated significantly less favorably than did the participants without SICS for comfort during the day (7.9±1.7 vs. 8.5±1.4, P=0.03), comfort at the end of the day (6.6±2.1 vs. 7.4±1.9, P=0.03), overall dryness (7.4±1.9 vs. 8.0±1.7, P=0.04), dryness at the end of the day (6.7±2.2 vs. 7.5±2.1, P=0.01), feelings of burning and stinging (8.5±2.0 vs. 8.9±1.8, P=0.02), and overall vision (8.2±1.6 vs. 8.7±1.3, P<0.001). Conclusions: The participants with SICS had lower subjective comfort and vision compared with those who did not experience SICS.

Consequences of wear interruption for discomfort with contact lenses.

Purpose To establish whether increased end-of-day discomfort during soft contact lens wear is associated with short-term changes occurring to the lens itself. Methods Twenty-seven subjects wore hydrogel lenses (Focus Dailies; Alcon) bilaterally for 10 hours on two separate days. Comfort was reported using 1–100 numerical rating scales (1 = intolerable discomfort, 100 = lens cannot be felt). Day 1 ratings were taken before lens insertion and at 0.05, 5, and 10 hours post-insertion. Day 2 ratings occurred at similar times, but lenses were removed after the 5-hour assessment and either reinserted (n = 14) or newly replaced (n = 12). An additional rating was taken 5 minutes after re-insertion. Wear then continued to the 10-hour point. In a separate study, 24 different subjects repeated these procedures using a silicone hydrogel lens (AirOptix Aqua; Alcon) with wear taking place on 3 days to permit lens replacement to be with existing as well as new lenses in all subjects. Results For hydrogel lenses, comfort scores (mean ± 95% CI) reported after 10 hours were 79.4 ± 8.3 when lenses were worn un-replaced, compared with 73.2 ± 9.2 for replacement with the existing lens. When replacement was with a brand new lens, the corresponding values were 72.9 ± 10.9 (un-replaced) versus 69.2 ± 12.8 (new lens replacement). For silicone hydrogel lenses, 10-hour comfort was 90.3 ± 3.2 (un-replaced) versus 92.2 ± 2.9 (replacement with existing lens) versus 90.0 ± 3.3 (replacement with new lens). Differences between replacement conditions were not significant in any case (analysis of variance, p > 0.05). Conclusions Final comfort was not influenced by replacing lenses midway through the wearing period. Comfort decrements experienced by users of these daily contact lenses towards the later part of the wearing period are not caused by changes occurring to the lenses on this time scale. Possible alternative etiological factors include a fatigue-like response in one or more ocular tissues or stimulation of ocular surface nociceptors induced by the presence of the contact lens.

Effect of lens and solution choice on the comfort of contact lens wearers.

Purpose To determine if the ocular comfort of symptomatic contact lens (CL) wearers can be substantially influenced by choosing a better or worse performing CL–lens care product (LCP) combination. Methods Twenty-four symptomatic and 13 nonsymptomatic CL wearers were enrolled into a prospective, crossover, randomized clinical trial. Two CL-LCP combinations were chosen from studies previously conducted at the Brien Holden Vision Institute that were found to provide the best (galyfilcon A/polyhexanide, combination 1) and worst performance (balafilcon A/polyquaternium-1 and myristamidopropyl dimethylamine + TearGlyde, combination 2) in terms of end-of-day comfort. Subjects were not informed whether they were categorized as symptomatic or nonsymptomatic nor were they aware of the rankings of each CL-LCP combination. Subjects were randomly allocated to one of the CL-LCP combinations for 8 days on a daily wear basis. Contact lens fitting was assessed after insertion from the packaging solution. Take-home questionnaires assessing ocular comfort and dryness (1 to 10 numeric rating scale) were completed on insertion and after 2 and 8 hours of wear on days 2, 4, and 6. Ocular symptoms were assessed on days 2, 4, and 6 after 8 hours of wear. A 48-hour washout period during which CLs were not worn was applied, with the procedure repeated using the second combination. Results In symptomatic subjects, combination 1 was rated significantly better than combination 2 after 8 hours of wear for ocular comfort (7.7 ± 1.3 vs. 7.1 ± 1.5, p = 0.01) and ocular dryness (7.5 ± 1.6 vs. 7.0 ± 1.6, p = 0.045), with less frequent symptoms of ocular dryness (p < 0.01) and lens awareness (p < 0.01) reported. No significant differences were found in nonsymptomatic subjects. Conclusions Ocular comfort and symptoms in symptomatic CL wearers can be perceptibly improved by switching to an alternative CL-LCP combination. This finding provides justification for the efforts of both eye care practitioners and researchers to improve the comfort of CL wearers.

The effect of compliance on contact lens case contamination.

Purpose To determine the efficacy of written instructions on contact lens case hygiene and to quantify the effect of noncompliance on contact lens case contamination. Methods Data were retrospectively analyzed from 16 prospective, 3-month daily-wear studies during which six commercially available silicone hydrogel contact lenses and seven lens care solutions (LCS) were tested following a similar protocol. Verbal instructions regarding case hygiene (rinse case with LCS, not tap water) were given in nine studies, while the same instructions were given verbally and in written format in seven studies. A survey on contact lens, LCS, and lens case hygiene was completed at 1- and 3-month visits and compliance with case hygiene instructions was determined. Regular contact lens cases were used for 1 month and collected for microbial analysis at the 1- and 3-month visits. The rate of case contamination and the types of microbes contaminating cases were evaluated. Results Participants given verbal and written instructions were more likely to be compliant with case hygiene instructions than those just given verbal instructions (odds ratio [OR]: 2.19, p < 0.001, 95% confidence interval [CI]: 1.40–3.44). The overall case contamination rate was 79%. Use of tap water to rinse contact lens cases was associated with significantly more cases contaminated with Gram-negative bacteria (GNB) (30% vs. 10%, p < 0.001), a greater risk of GNB case contamination (OR: 2.91, p < 0.001. 95% CI: 1.72–4.92), and a higher quantity of GNB in cases (mean colony-forming unit/case ± SD: 28,286 ± 131,935 vs. 6477 ± 60,447, p < 0.001). Conclusions Lens case hygiene can be improved by effective communication of instructions. Contact lens wearers should be actively discouraged from rinsing contact lens cases with tap water because of the increased risk of GNB contamination.

Ocular discomfort responses after short periods of contact lens wear.

Purpose To investigate if contact lens–related discomfort is a function of the time of day at which lenses are worn. Methods This was a randomized, crossover, open-label clinical trial where subjective responses, with and without contact lenses, were assessed every 2 hours during five stages (A to E). Each stage began at the time when subjects would normally have inserted their contact lenses (T0). During stage A, no lenses were worn, whereas in stage B, lenses were worn continuously for 12 hours. In stages C to E, lenses were worn for only 4 hours. Contact lenses were inserted at T0 for stage C, but for stages D and E, lenses were not inserted until T0 + 4 and T0 + 8 hours, respectively. Mixed linear models were used for statistical analysis. Results In the absence of contact lenses, ocular comfort and dryness remained reasonably constant throughout the observation period. Ocular comfort and dryness decreased during 12 hours of continuous lens wear and became significantly worse from the 8-hour time onward compared with insertion (p < 0.023). There were no significant differences in terms of ocular comfort and dryness between any of the 4-hour lens wear stages (p < 0.82). During each 4-hour stage, both comfort and dryness behaved in a similar fashion (p > 0.05) to the first 4 hours of continuous contact lens wear. Comparing the scores of each of these stages with the no-lens response at the corresponding time showed no significant differences for comfort (p > 0.23) or dryness (p > 0.37). Conclusions Short periods of wear can be experienced at any time of day without significant change in ocular discomfort and dryness. This suggests that subjective responses at the end of the day are determined by the length of time lenses are in contact with the eye, rather than the time of day at which lenses are worn.

Short-Term Visual Performance of Novel Extended Depth-of-Focus Contact Lenses.

Purpose To compare the objective and subjective visual performance of a novel contact lens which extends depth of focus by deliberate manipulation of higher-order spherical aberrations and a commercially available zonal-refractive multifocal lens. Methods A prospective, cross-over, randomized, single-masked, short-term clinical trial comprising 41 presbyopes (age 45 to 70 years) wearing novel Extended Depth of Focus lenses (EDOF) and ACUVUE OAYS for Presbyopia (AOP). Each design was assessed on different days with a minimum overnight wash-out. Objective measures comprised high-contrast visual acuity (HCVA, logMAR) at 6 m, 70 cm, 50 cm, and 40 cm; low-contrast visual acuity (LCVA, logMAR) and contrast sensitivity (log units) at 6 m; and stereopsis (seconds of arc) at 40 cm. HCVA at 70 cm, 50 cm, and 40 cm were measured as “comfortable acuity” rather than conventional resolution acuity. Subjective performance was assessed on a 1–10 numeric rating scale for clarity of vision and ghosting at distance, intermediate and near, overall vision satisfaction, ocular comfort, and lens purchase. Statistical analysis included repeated measures ANOVA and paired t tests. Results HCVA, clarity of vision, and ghosting with EDOF were significantly better than AOP (p < 0.01); however, differences were dependent on testing distances and add groups. Post hoc analysis showed EDOF was significantly better than AOP for HCVA at 70 cm (0.11 ± 0.11 vs. 0.21 ± 0.16, p < 0.001), 50 cm (0.26 ± 0.17 vs. 0.36 ± 0.18, p = 0.003), 40 cm (0.42 ± 0.17 vs. 0.52 ± 0.21, p = 0.001), and LCVA at 6 m (0.22 ± 0.08 vs. 0.27 ± 0.12, p = 0.024). EDOF was significantly better than AOP for clarity of vision at distance (7.7 ± 1.6 vs. 6.8 ± 2.3, p = 0.029), intermediate (8.8 ± 1.4 vs. 7.0 ± 2.2, p < 0.001), and near (7.4 ± 2.4 vs. 5.2 ± 2.7, p < 0.001), ghosting at distance (9.1 ± 1.2 vs. 8.1 ± 2.5, p = 0.005), and overall vision satisfaction (7.6 ± 1.6 vs. 6.0 ± 2.6, p < 0.001). More participants chose to purchase EDOF compared to AOP (61 vs. 39%) and significantly more chose to only-purchase EDOF compared to only-purchase AOP (27 vs. 5%, p = 0.022). Conclusions When compared with AOP, EDOF lenses provide better intermediate and near vision performance in presbyopic participants without compromising distance vision.

Prompt diagnosis and treatment of microbial keratitis in a daily wear lens.

Purpose. Microbial keratitis (MK) is a serious sight-threatening complication occurring with and without contact lens wear. The task of diagnosing MK is difficult because each presentation of the disease is different and can be mistaken for noninfectious ulcers such as contact lens peripheral ulcer (CLPU). The purpose of this article is to present a case report of MK initially diagnosed as a CLPU. Case Report. We report the incidence of a 21-year-old female presenting with signs and symptoms in her left eye, which initially suggested a CLPU. At the 24-h follow-up, contrary to expected indications of healing, her condition had deteriorated. The diagnosis was reevaluated as an MK. Ciloxan was prescribed under care of an ophthalmologist. Despite initial misdiagnosis, due to aggressive topical treatment and the peripheral location of the lesion, <1 line of vision was lost. Discussion. Defined signs and symptoms criteria have been established for the differential diagnoses of MK and CLPU. However, there is often an overlap in the signs and symptoms that can complicate the diagnosis. A critical sign, however, is progress immediately after lens wear is discontinued. Prophylaxis and rapid appropriate treatment and follow-up are vitally important if there is any doubt and to ensure correct diagnosis and resolution. Conclusion. Any diagnosis of CLPU must be monitored carefully to ensure it is not MK. Prompt diagnosis and treatment of MK are essential for a good visual outcome.

Short-term visual performance of soft multifocal contact lenses for presbyopia.

PURPOSE To compare visual acuity (VA), contrast sensitivity, stereopsis, and subjective visual performance of Acuvue® Oasys® for Presbyopia (AOP), Air Optix® Aqua Multifocal (AOMF), and Air Optix® Aqua Single Vision (AOSV) lenses in patients with presbyopia. METHODS A single-blinded crossover trial was conducted. Twenty patients with mild presbyopia (add ≤+1.25 D) and 22 with moderate/severe presbyopia (add ≥+1.50 D) who wore lenses bilaterally for 1 h, with a minimum overnight washout period between the use of each lens. Measurements included high- and low-contrast visual acuity (HCVA and LCVA, respectively) at a distance, contrast sensitivity (CS) at a distance, HCVA at intermediate (70 cm) and near (50 cm & 40 cm) distances, stereopsis, and subjective questionnaires regarding vision clarity, ghosting, overall vision satisfaction, and comfort. The test variables were compared among the lens types using repeated-measures ANOVA. RESULTS Distance variables (HCVA, LCVA, and CS) were significantly worse with multifocal lens than with AOSV lens (p≤0.008), except for AOMF lens in the mild presbyopia group in which no significant difference was observed (p>0.05). Multifocal lenses had significantly greater HCVA at 40 cm than AOSV lens (p≤0.026). AOMF lens had greater intermediate HCVA than AOP lens (p<0.03). AOP lens demonstrated greater improvements in stereopsis than AOMF and AOSV lens in the moderate/severe presbyopia group (p≤0.03). Few significant differences in subjective variables were observed, with no significant difference in the overall vision satisfaction observed between lens types (p>0.05). The proportions of patients willing to buy AOSV, AOMF, and AOP lenses were 20%, 40%, and 50%, respectively, in the mild presbyopia group and 14%, 32%, and 23%, respectively, in the moderate/severe presbyopia group; however, these differences were not statistically significant (p≥0.159). CONCLUSIONS Further development of multifocal lenses is required before significant advantages of multifocal lenses over single vision lens are observed in patients with presbyopia.

Extended depth of focus contact lenses vs. two commercial multifocals: Part 2. Visual performance after 1 week of lens wear

Purpose To compare the visual performance of prototype contact lenses designed via deliberate manipulation of higher-order spherical aberrations to extend-depth-of-focus with two commercial multifocals, after 1 week of lens wear. Methods In a prospective, participant-masked, cross-over, randomized, 1-week dispensing clinical-trial, 43 presbyopes [age: 42–63 years] each wore AIROPTIX Aqua multifocal (AOMF), ACUVUE OASYS for presbyopia (AOP) and extended-depth-of-focus prototypes (EDOF) appropriate to their add requirements. Measurements comprised high-contrast-visual-acuity (HCVA) at 6 m, 70 cm, 50 cm and 40 cm; low-contrast-visual-acuity (LCVA) and contrast-sensitivity (CS) at 6 m and stereopsis at 40 cm. A self-administered questionnaire on a numeric-rating-scale (1–10) assessed subjective visual performance comprising clarity-of-vision and lack-of-ghosting at various distances during day/night-viewing conditions and overall-vision-satisfaction. Results EDOF was significantly better than AOMF and AOP for HCVA averaged across distances (p ≤ 0.038); significantly worse than AOMF for LCVA (p = 0.021) and significantly worse than AOMF for CS in medium and high add-groups (p = 0.006). None of these differences were clinically significant (≤2 letters). EDOF was significantly better than AOMF and AOP for mean stereoacuity (36 and 13 seconds-of-arc, respectively: p ≤ 0.05). For clarity-of-vision, EDOF was significantly better than AOP at all distances and AOMF at intermediate and near (p ≤ 0.028). For lack-of-ghosting averaged across distances, EDOF was significantly better than AOP (p < 0.001) but not AOMF (p = 0.186). EDOF was significantly better than AOMF and AOP for overall-vision-satisfaction (p ≤ 0.024). Conclusions EDOF provides better intermediate and near vision performance than either AOMF or AOP with no difference for distance vision after 1 week of lens wear.

Predicting Short-term Performance of Multifocal Contact Lenses

Objective: To investigate if initial multifocal contact lens (MFCL) performance predicts short-term dispensing performance. Methods: A retrospective analysis of 55 participants (Px) in a masked, crossover, clinical trial, using ACUVUE OASYS for Presbyopia and AIR OPTIX AQUA Multifocal. Subjective questionnaires were administered at the following instances: initial fitting, two take home questionnaires (THQ) completed between days 2 and 4 and at assessment, ≥5 days after fitting. Questionnaires included vision clarity and lack of ghosting at distance, intermediate and near at day/night time points rated on a 1 to 10 (1-step, 10 most favorable) rating scale. Vision stability, vision while driving, overall vision satisfaction, willingness to purchase and comfort, as well as acuity-based measures were also collected. Results: There were no statistical differences in comfort and vision at all distances, in vision stability or driving at either time points between THQ and assessment (P>0.05). However, there was a statistical decline in subjective overall vision satisfaction and comfort between fitting and assessment visits (P<0.001). Willingness to purchase remained the same at fitting and assessment in 68% of Px, whereas only 4% of Px converted to a positive willingness to purchase at assessment. The majority of acuity-based measures remained constant between fitting and assessment visits. Conclusion: Initial performance at fitting was not able to predict short-term performance of MFCL. Subjective measures peaked at fitting and declined thereafter whereas acuity-based measures remained constant. Utility of subjective rating tools may aid practitioners to gauge success of MFCL.