Impact of a Rub and Rinse on Solution-Induced Corneal Staining

A novel scale for describing corneal staining

The assessment of corneal staining is a commonly conducted procedure in both clinical practice and as part of various research studies. Different grading scales are employed by many clinicians and researchers to undertake this procedure for corneal staining comparisons between eyes, products and over time. This paper describes the development and use of a grading scale for corneal staining undertaken at an academic research site. The scale involves assessment of three factors across five corneal zones: type, area and depth. Staining type and area are graded on a 0–100 scale, and depth is graded on a 0–4 scale. These factors can be combined to create a three- or two-factor staining grade, or the factors may be reported individually. An additional benefit of this scale is that the staining scores may be reported by zone as “zone staining scores” or the scores of zones may be combined to provide an overall corneal “global staining score”.

Daily versus monthly disposable contact lens: Which is better for ocular surface physiology and comfort?

PURPOSE

To investigate the effect of soft contact lenses (SCL) wearing modality and lens materials on the changes in conjunctival bulbar and limbal redness and conjunctival and corneal staining after two months of SCL wear. Comfort level was also analyzed.

METHODS

In this longitudinal clinical trial, forty-seven neophyte myopic subjects were fitted with a monthly disposable lens (lotrafilcon-B or comfilcon-A or balafilcon-A) in one eye and a daily disposable lens (nelfilcon-A or stenofilcon-A or nesofilcon-A) in the other eye, randomly selected. Conjunctival bulbar and limbal redness and conjunctival and corneal staining were evaluated before and after lens wear. Effect of lens wearing modality and lens materials on these changes was also determined. Level of comfort was evaluated subjectively twice per day. Comfort level and reduction in end-of-day comfort were compared between different lens wearing modalities and materials.

RESULTS

Bulbar and limbal redness and conjunctival and corneal staining were increased (p<0.001) after lens wear, and changes were similar with daily and monthly disposable lens wear (p>0.05). Limbal redness was associated with lens materials, and lotrafilcon-B induced the least among the studied lenses (p<0.05). There was no significant association between the wearing modality and the average comfort level and reduction of end-of-day comfort (p>0.05).

CONCLUSION

Two months of SCL wear increased conjunctival redness, conjunctival and corneal staining, which were not associated with the lens wearing modality. There was a reduction in end-of-day comfort, similar to daily and monthly lenses. The change in limbal redness and reduction in end-of-day comfort were associated with the characteristics of the lens material.

Pilot Study to Determine the Effect of Lens and Eye Rinsing on Solution-Induced Corneal Staining (SICS)

PURPOSE

The main purpose of this study was to determine whether two interventions (rinsing the lens before lens insertion and rinsing the ocular surface post-lens removal) had any impact on solution-induced corneal staining (SICS). In addition, the presence of hyper-reflective epithelial cells in the presence of SICS was investigated.

METHODS

Twenty subjects wore new balafilcon A lenses, which had been soaked overnight in a multipurpose care product containing polyhexamethylene biguanide for 2 hours. The study was conducted across three phases. In phase 1 (investigator and subject masked, randomized eye), one lens was rinsed with nonpreserved saline before lens insertion. In phase 2 (investigator masked, randomized eye), one eye was rinsed with nonpreserved saline after lens removal, before staining assessment. Corneal staining was recorded as the percentage area of the cornea exhibiting superficial punctate staining. In both phases, ocular comfort and presence of specific symptoms were captured. In phase 3, there was no randomized treatment; confocal images of the epithelium were obtained after 2 hours of wear.

RESULTS

In phase 1 (lens-rinse), there was no significant difference in staining between the treated and untreated eyes (84 vs. 92%, respectively; p = 0.06). In phase 2 (eye-rinse), there was also no significant difference between the treated and untreated eye (86 vs. 86%, p = 0.92). Most subjects were asymptomatic. In phase 3, images of hyper-reflective cells were captured in 97% of the eyes imaged.

CONCLUSIONS

The two rinsing procedures did not affect the level of the SICS response. Hyper-reflective epithelial cells were found to be present in a significant number of eyes exhibiting SICS, and their presence warrants further investigation.

Short-term clinical comparison of two dual-disinfection multipurpose disinfecting solutions

OBJECTIVE

To compare the short-term clinical performance of two dual-disinfectant multipurpose disinfecting solutions (MPDS) when used in conjunction with two silicone hydrogel contact lenses.

METHODS

Participants wore galyfilcon A and balafilcon A lenses, randomly allocated one type to each eye. Multipurpose disinfecting solutions were double-masked and allocated using a randomized crossover design. Lenses were presoaked overnight in the allocated MPDS, containing either polyquaternium-1/alexidine dihydrochloride (PQ-alexidine) or polyquaternium-1/myristamidopropyl dimethylamine (PQ-MAPDA). Lenses were worn daily for 4 days and disinfected with the same MPDS in which they had been soaked. Clinical assessments occurred immediately after insertion, 2 hours after insertion, and after 2 hours of wear on day 4. Subjective ratings were collected at each assessment and after 6 hours of wear on days 1 to 3. Linear mixed models were used for statistical analysis.

RESULTS

Solution-induced corneal staining (SICS) incidence was significantly different between MPDS lens combinations (P=0.01) with PQ-MAPDA-balafilcon A showing the highest incidence (27.8%). The incidence of SICS was significantly higher when balafilcon A lenses were worn compared with galyfilcon A (19.4% vs. 2.8%; P=0.04). There was no significant difference in SICS incidence between MPDS (PQ-alexidine=5.6%, PQ-MAPDA=16.7%; P=0.08). Polyquaternium-1/alexidine dihydrochloride was associated with significantly fewer symptoms of burning/stinging (9.7±0.6 vs. 9.1±2.2; P=0.03) and self-assessed redness (9.8±0.5 vs. 9.2±1.9; P=0.03) on initial lens insertion. There were no significant differences between MPDS for comfort ratings (P>0.05).

CONCLUSION

These short-term clinical results provide an initial indication that PQ-alexidine is associated with fewer symptoms on insertion but no significant difference in ocular comfort compared with PQ-MAPDA. Longer studies are required to provide further evidence.

Predisposing factors for solution-induced corneal staining

PURPOSE

To evaluate predisposing factors in subjects susceptible to solution-induced corneal staining (SICS).

METHODS

Four hundred forty-six existing soft contact lens wearers were randomly fitted with one of two study lenses (lotrafilcon B, CIBA Vision, or omafilcon A, CooperVision) and used a hydrogen peroxide care system (Clear Care, CIBAVision) for a 1-month period. Each subject was then challenged with the same lenses presoaked in a multipurpose solution (ReNu MultiPlus, Bausch & Lomb) and assessed after approximately 2 h to be categorized as either "stainers" or "non-stainers" based on whether they showed a classic SICS pattern (diffuse punctate corneal staining in three or more peripheral quadrants).

RESULTS

Overall, 36% (155 of 425) of eligible subjects were classified as stainers and included a higher proportion of omafilcon wearers: 44% (91 of 205) vs. 29% (64 of 220). After using the peroxide system, the stainers were more likely to show poorer wetting (odds ratio [OR] = 1.76, p = 0.02) compared with the non-stainers. Lens wetting showed a significant negative correlation with film deposits (r = -0.63, p < 0.0001, n = 425). Furthermore, on slit lamp examination, the stainers were more likely to show higher levels of upper- and lower-palpebral hyperemia (OR = 2.18, p = 0.02; OR = 1.93, p = 0.04), tarsal roughness (OR = 1.71, p = 0.01), corneal staining (OR = 17.1, p < 0.0001), and conjunctival staining (OR = 1.94, p = 0.004). Although not exposed to preservatives, twice as many eyes in the stainers group had some level of corneal staining: 51% vs. 25%. There were no significant differences between the stainers and non-stainers with respect to age, sex, refraction, or keratometry (p > 0.05).

CONCLUSIONS

This study highlighted some notable trends in patients susceptible to SICS. The findings point toward poor tear quality as a predisposing factor for SICS.

Multipurpose soft contact lens care in Japan

Purpose

To assess the use of multipurpose lens care products via an online survey conducted among soft contact lens (SCL) wearers in Japan.

Methods

The subjects were 1000 men and women aged 15–44 years who reported that they cleaned their SCL by using multipurpose solution at least twice a week. Via the internet, they were asked questions about SCL care, the use of a rubbing step when cleaning SCL, cleaning and replacing lens cases, and recommended SCL care methods.

Results

Of the 1000 SCL wearers enrolled, 94.3% performed lens care every day lenses were worn, 64.2% reported rubbing the lenses every time, 57.9% rubbed the lenses for at least 10 seconds per side, and 64.7% reported they rubbed the lenses on both sides. Further, 61.2% reported that they had been given an explanation of SCL cleaning at an eye clinic or contact lens store. Only 49.8% of subjects reported that they cleaned the lens case every time and 61.7% replaced the case within 3 months. Only 19.5% had been given an explanation about lens case care. Half of the subjects reported they had been given no recommendation to use specific SCL care products or could not remember whether or not they had. The most common reason for the recommendation was good compatibility with their type of lens.

Conclusion

More education is needed in Japan regarding methods of SCL care to ensure correct lens cleaning with inclusion of a rubbing step, as well as sufficient cleaning and replacement of the lens case. Of particular interest is the finding that many subjects were not given an explanation about proper SCL care and lens case cleaning and replacement at the time of lens purchase or prescription.