Renee Garofalo

Corneal Staining and Subjective Symptoms With Multipurpose Solutions as a Function of Time

Purpose. Short-term changes in corneal staining and ocular symptoms were assessed at defined intervals to evaluate combinations of three soft lenses and four multipurpose solutions. Methods. A series of pilot studies were conducted over 11 months using a double-masked, randomized, crossover design. Asymptomatic, adapted, daily-wear soft lens users wore group II or IV soft hydrophilic or silicone hydrogel lenses for a maximum period each day. Before wear, new lenses were soaked overnight in one of four multipurpose solutions: Alcon OPTI-FREE Express MPDS, Bausch & Lomb ReNu MultiPlus Multipurpose Solution, CIBA Vision SOLO-Care PLUS Multipurpose Solution, or AMO Complete MoisturePLUS. Subjects rated comfort and ocular symptoms. Corneal staining type and area were evaluated at baseline and after lens removal. Results. Significantly increased extent of corneal staining, defined as the proportion of corneal zones showing staining of grade 1 or more severe, was observed at 1 and 2 hours when subjects wore group II lenses soaked in the polyhexamethylene biguanide-based systems. Significantly increased extent of staining was observed at 2 hours when subjects used silicone hydrogel lenses soaked in regimen 4. When subjects used regimen 1 and wore group II lenses, only a minimal staining response was observed at 1 and 2 hours of wear. Significant symptoms were not correlated with extent of staining. Conclusions. This study design is a promising tool that can discriminate between the performance of different soft lens and multipurpose solution combinations rapidly using small patient samples. With some lens-care product combinations, corneal appearance may vary according to the time of day the patient is examined.

Contact lens-induced circumlimbal staining in silicone hydrogel contact lenses worn on a daily wear basis.

Objectives: The principal objective of the study was to measure the conjunctival staining produced in the circumlimbal region by silicone hydrogel contact lenses with different edge designs. The secondary objective was to investigate the association between circumlimbal staining and comfort. Methods: Four silicone hydrogel contact lenses: ACUVUE OASYS (knife edge design), AIR OPTIX, Biofinity (chisel edge rounded edge combination), and PureVision (rounded edge design), and 1 hydrogel contact lens, ACUVUE 2 (knife edge design), were tested. The study was conducted on a cohort population of 27 established soft contact lens wearers, who wore each contact lens type, in a random order, for a period of 10 (±2) days. Circumlimbal staining was measured in a double-masked fashion through image analysis of digital photographs of lissamine green taken under controlled experimental conditions. Results: The results obtained showed that contact lens edge design was the primary factor controlling circumlimbal staining for silicone hydrogel lenses: a rounded edge away from the ocular surface produced the lowest staining (average, 0.19%) and a knife edge in close apposition to the ocular surface produced the highest staining (average, 1.34%). Contact lens material rigidity was also identified to affect circumlimbal staining and an inverse association between circumlimbal staining and contact lens comfort was demonstrated: the rounded edge design produced the lowest comfort (72 of 100) and the knife edge design produced the highest (87 out of 100). Conclusion: Soft contact lens wear induces circumlimbal staining, the level of staining being influenced by the contact lens edge design. However, high level of circumlimbal staining is not associated with decreased comfort.

The effect of soft contact lens care products on lens modulus

PURPOSE To examine the relative changes in modulus of nine soft contact lens materials when exposed to three lens care solutions. METHOD Measurements of elastic modulus were made using an Instron 3343 tensiometer of lenses which had been pre-soaked in ReNu Multi-Purpose (Bausch & Lomb), OPTI-FREE RepleniSH (Alcon), Clear Care (CIBA Vision) hydrogen peroxide, or a saline control solution for one week. The solutions were changed three times during the week-long soaking period. Following this, the lenses were measured for centre thickness and were cut into two samples of identical width. Youngs modulus was measured in the force range of 0.015-0.035 N. RESULTS Measurements in saline ranged form 0.31MPa for etafilcon A to 1.76 MPa for lotrafilcon A. All of the lenses, with the exception of senofilcon A, displayed a significant change in modulus with at least one of the solutions. Both etafilcon A and lotrafilcon B showed a significant change in modulus with all solutions. With lotrafilcon B in hydrogen peroxide solution, modulus reduced from 1.32 to 0.93 MPa (P<0.0001). Galyfilcon A decreased from 0.36 to 0.31 MPa in ReNu Multi-Purpose (P<0.0001) and lotrafilcon A decreased from 1.76 to 1.64 MPa in OPTI-FREE RepleniSH (P=0.04). Comfilcon A increased from 0.78 to 0.85 MPa (P<0.0001) in peroxide. CONCLUSIONS The use of some contact lens-solution combinations results in significant changes in modulus. In the case of the multi-purpose solutions, the changes probably relate to uptake of the formulation components and, in the case of peroxide, to chemical changes to the polymer.

The effect of temperature on soft contact lens modulus and diameter.

Purpose: To examine the relative changes in diameter and modulus of soft contact lenses when the temperature is raised from room temperature (RT) to eye temperature (ET). Methods: Thirteen lens types including 9 silicone hydrogel lenses were measured for diameter and elastic modulus at RT (20 ± 1°C) and ET (34 ± 1°C). Lens diameter measurements were undertaken after equilibration in ISO saline in a temperature-controlled lens analyzer (Optimec, Ltd, Malvern, United Kingdom). Measurements of flexural modulus of elasticity were made using an Instron 3343 tensiometer (Instron, Norwood, MA) with the samples suspended in a temperature-controlled saline bath. Results: All lens types reduced in diameter when raised to ET. The largest mean changes with silicone hydrogel and conventional hydrogel lenses were with Biofinity (Δ0.35 mm) and Acuvue 2 (Δ0.28 mm), respectively. All the silicone hydrogels showed a statistically significant reduction in modulus when raised to ET ranging from Δ0.06 MPa with comfilcon A to Δ0.78 MPa with balafilcon A. All the conventional hydrogels showed relatively small changes (<0.05 MPa) in modulus. Two of the four conventional hydrogels showed a statistically significant change in modulus (etafilcon A and ocufilcon A), but these were small and believed to be clinically insignificant. Conclusions: This study has highlighted some clinically relevant changes in soft contact lens modulus and diameter when raised from RT to ET. It has also shown the importance of standardizing modulus measurement technique.

Contact lens lipid spoliation of hydrogel and silicone hydrogel lenses.

Purpose The purpose of the study was to measure contact lens lipid spoliation of silicone hydrogel PureVision (balafilcon A) and hydrogel Acuvue 2 (etafilcon A) contact lenses worn for 10 hours single use (DD) and 7 days of extended wear (EW). Methods Two similar study populations (DD, n = 55; EW, n = 53), were enrolled at four study sites. In each population, a bilateral, randomized, crossover (lens material), subject-masked experimental design was followed. Worn contact lenses were analyzed for lipid uptake using high-performance liquid chromatography by two laboratories: Alcon Laboratories (right lens total uptake) and OTG Research & Consultancy (left lens total uptake and individual lipid classes). Results Lipid uptake was different for the two materials: total lipid (p < 0.007), cholesterol esters (p < 0.001), cholesterol (p < 0.001 EW only), and triglycerides/phospholipids (p < 0.001) were higher for balafilcon A, whereas fatty acid (p < 0.0025 EW only) was higher for etafilcon A. The ratio of the extracted lipids was also different: higher percentages of triglycerides/phospholipids (p < 0.001) and cholesterol (p < 0.001 EW only) for balafilcon A and higher percentages of fatty acids/di- and monoglycerides (p < 0.014) for etafilcon A. Conclusions Total lipid uptake was highly material dependent. Both laboratories measured a greater uptake of lipids by the silicone hydrogel than the hydrogel material, a difference that was evident after only 10 hours of DD. Total lipid uptake was greater after 7 days of EW compared with 10 hours of DD. Of interest for contact lens spoliation and its avoidance was the differential lipid uptake profile, indicating material selectivity. Whereas greater differentiation between materials was possible after 7 days of EW for each material, the lipid uptake profile was similar for DD and EW, indicating a greater material effect than a wear modality effect.

Poster 16 - Correlating Biocide Uptake and Release Profiles with Corneal Staining and Subjective Symptoms

Purpose: To determine if the interactions of lens care preservatives with contact lenses is an important factor in clinical signs and symptoms. Methods: This study evaluated uptake and release profiles of two preservatives used in MPS products, alexidine contained in ReNu® with MoistureLocTM and POLYQUAD® (polyquaternium-1) contained in OPTI-FREE® Express®. Three lens materials were used in a cross over study design: SofLensTM 66 (alphafilcon A), Acuvue® 2 (etafilcon A) and Acuvue® AdvanceTM (galyfilcon A, with HYDRACLEARTM). Asymptomatic, adapted daily wear soft lens users wore groups I and IV soft hydrophilic or silicone hydrogel lenses for a maximum of 2, 4 and 6 hrs each day. New lenses were dispensed for each wear period. The worn lenses were analyzed for preservative content using HPLC and release profiles calculated. Short-term changes in corneal staining and ocular symptoms were assessed at defined time intervals following lens insertion in order to compare these ocular findings with laboratory uptake and release properties. Results: All three lens types uptake alexidine during an overnight soaking period. The rate of preservative release during wear depended on the lens type. After 2 hours, Acuvue® 2 and SofLensTM 66 released 46% and 77% of alexidine, respectively. Acuvue® AdvanceTM released 27% of the preservative in two hours. Clinically significant corneal staining was observed at 2 and 4 hours when subjects wore Acuvue® 2 and Acuvue® AdvanceTM lenses soaked in the alexidine-based system. At the 2 hour interval, extent of corneal staining increased in all subjects with Acuvue® 2 lenses, and 50% of the subjects with Acuvue® AdvanceTM lenses. Only minimal staining was observed for SofLensTM 66 at 2, 4 and 6 hours. Symptoms were not correlated with the extent of staining. Lenses cycled in the POLYQUAD® based product showed minimal uptake into lenses and corneal staining was low with all lens materials tested. Conclusions: The study demonstrated the difference in uptake/release profiles for MPS products preserved with alexidine or POLYQUAD ® using 3 soft lens materials. For some lens materials these differences in biocide uptake/release appear to be correlated with corneal staining patterns but not symptoms.

Clinical evaluation of a new multi-purpose disinfecting solution in symptomatic wearers of silicone hydrogel contact lenses

Correspondence: Renee Garofalo Alcon Research Ltd, 6201 South Freeway, TC-44, Fort Worth, TX 76134, USA Tel +1 817 615 2712 Fax +1 817 615 4602 Email renee.garofalo@alconlabs.com Background: The purpose of this study was to evaluate the safety and efficacy of a new multi-purpose disinfecting solution containing a diblock copolymer, poly(oxyethylene)poly(oxybutylene), designed to improve the wetting properties of silicone hydrogel lenses in patients with symptoms of discomfort. Methods: This 30-day, randomized, concurrently controlled, double-masked, multi-site study involved 589 subjects at 42 investigational sites in the US. Existing symptomatic lens wearers were randomly assigned to either regimen 1 (OPTI-FREE PureMoist, Alcon Laboratories Inc,) a newly developed formulation containing the diblock copolymer), or regimen 2 (renu freshTM multi-purpose solution Bausch + Lomb, Inc). On days 0, 14 and 30, subjects assessed acceptability and comfort using seven Likert-type questions, rated the intensity of ocular symptoms (comfort, dryness, irritation, scratchiness, burning, stinging) on a visual analog scale (0–100), as well as reported lens wearing time, comfortable lens wearing time, and rewetting drop frequency. The investigators assessed slitlamp findings (including circumlimbal conjunctival lissamine green staining and corneal fluorescein staining), on-eye lens surface wettability and deposits, visual acuity, and adverse events. Results: Differences favoring regimen 1 were noted on Day 30 for the primary Likert statement “I can comfortably wear my lenses” (P = 0.047) and for comfortable lens wear time (P = 0.041). Symptoms of ocular scratchiness, ocular burning, and ocular stinging were all rated lower after 30 days of use by subjects using regimen 1 compared with those using regimen 2 (P # 0.024). Circumlimbal conjunctival staining (sum score) was significantly lower with regimen 1 (P , 0.0001). Other parameters did not show any difference between the two treatment regimens. Conclusion: This study shows that the new multi-purpose disinfecting solution is safe and effective when used by symptomatic silicone hydrogel contact lens wearers. By improving symptoms of scratchiness, burning, stinging, and comfortable wear time, and decreasing circumlimbal conjunctival staining, the new multi-purpose disinfecting solution enhances the patient’s wearing experience and helps maintain optimal lens performance.