Effect of Daily Contact Lens Cleaning on Ocular Adverse Events during Extended Wear

Adhesion of Asian Dust Particles to Verofilcon a Soft Contact Lenses

PURPOSE

Asian dust poses a serious global health hazard. Airborne particles adhering to contact lenses may cause substantial damage to the ocular surface. The recently released one-day disposable silicone hydrogel soft contact lens (SCL), the verofilcon A, has a smooth surface with SMARTSURFACE^® technology, which is designed to prevent adhesion of protein components and foreign bodies. The purpose of this study was to verify the protective quality of verofilcon A SCL against adhesion of Asian dust particles to its surface.

METHODS

Verofilcon A and etafilcon A (control lens) SCLs were used (n=16 per group), and 0.2 mL of physiological saline containing 0.01 mg/mL of Asian dust particles was dropped on the surface of SCLs, allowed to stand for 1 hour, shaken for 1 minute, and rinsed three times with saline (after rinsing). In addition, the samples were agitated by a vortex mixer for 1 minute and rinsed three times with saline (after vortex). The number of Asian dust particles adhering to the SCLs and percentage of the surface area occupied by the Asian dust particles was determined before washing, after rinsing, and after vortexing.

RESULTS

The number of adherent Asian dust particles was lower on verofilcon A SCL (297 ± 116 after rinsing, and 5 ± 14 after vortexing) than on etafilcon A SCL (523 ± 212 after rinsing, p=0.003, and 378 ± 268 after vortexing, p<0.001). The Asian dust adhesion area was also lower on verofilcon A SCL (3.6 ± 2.3% after rinsing and 0.0 ± 0.1% after vortexing than on etafilcon A (10.2 ± 2.1% after rinsing, p=0.002, and 5.2 ± 3.0% after vortexing, p<0.001).

CONCLUSION

These findings indicate that verofilcon A SCL has the property of low adhesion of Asian dust particles. Verofilcon A SCL can be recommended for SCL wearers during windy and Asian dust days.

Evaluation of Pollen Adhesion to Verofilcon-A Soft Contact Lenses

Purpose:

A new 1-day disposable soft contact lens (SCL), verofilcon-A, constructed of silicone hydrogel material, has recently become available in Japan. This SCL has a very smooth surface produced by using the SMARTSURFACE ® Technology, and it was expected that pollen particles and protein components would not adhere easily to its surface. We examined the degree of pollen adhesion to the surface of the verofilcon-A material SCL and compared the results with those of other 1-day disposable SCLs (1DSCL).

Methods:

To determine the number of pollen grains attached to the surface of different types of SCLs, 0.01 mg/ml of cedar pollen solution was dropped onto the surface of 13 types of 1DSCL. After 24 h, each 1DSCL was rinsed in a shaker and washed five times with saline (n = 10 for each 1DSCL type). The number of pollen particles adhered to the 1DSCL and the percentage of surface area occupied by pollen was determined.

Results:

The number of pollen particles on the 1DSCLs ranged from 0 to 185 in the 200 × 200 µm area. The number of particles was lowest in the delefilcon-A and verofilcon-A SCLs with 0 particles, and the number was higher in the other 11 1DSCLs. The number of pollen particles was negatively correlated with the water content (r = −0.48), oxygen permeability (Dk; r = −0.43), oxygen transmissibility (r = −0.42), and center thickness (r = −0.33) of the 1DSCLs. The pollen adhesion area ranged from 0.0% to 3.1% and was lowest in the delefilcon-A and verofilcon-A 1DSCLs. There were significant differences in the pollen adhesion area between colored 1DSCLs (2.73 ± 1.97%) and clear 1DSCLs (1.03 ± 1.01%, P<0.001) and between hydroxyethyl methacrylate-based 1DSCLs (1.84 ± 1.45%) and silicone hydrogel-based 1DSCLs (0.05 ± 0.16%, P<0.001).

Conclusion:

These findings indicate that the verofilcon-A 1DSCL processed with SMARTSURFACE™ Technology is an excellent option for SCL users with allergic conjunctivitis during the high pollen season.

Adhesion of Pollen Particles to Daily Disposable Soft Contact Lenses

PURPOSE

Pollen and proteins attached to soft contact lenses (SCLs) exacerbate allergic conjunctivitis. The material of SCLs may affect the pollen adhesion to the SCLs. The factors associated with the number of pollen particles that are adherent to daily disposable SCL were investigated.

METHODS

Pollen particles were experimentally exposed to the contact lens surface of 12 types of SCLs for 1 hour, and the SCLs were washed and rinsed with a physiological saline (n=10 for each SCL type). A total of 120 contact lenses were used in this study. The pollen particles attached to the SCL were observed and photographed under a microscope. The influence of the materials of the SCLs on the degree of pollen adhesion were investigated.

RESULTS

The number of residual pollen particles attached to SCLs was in the range from 0-293/area of 200×200 µm. Percentage of pollen adhesion area of the surface of the SCL was in the range from 0.01% to 3.25%. There were significant differences in both the number and adhesion area of pollen particles among the 12 types of SCLs tested (P<0.0001 and P<0.0001, respectively). The number of pollen particles adhered to SCLs was significantly higher in colored SCLs than clear SCLs (unpaired t-test, p<0.001). The portion of pollen adhesion area was the lowest in the silicone hydrogel SCLs made with delefilcon-A (0.01 ± 0.02%).

CONCLUSION

Pollen adhesion in daily disposable SCLs depends on the characteristics and materials of the SCLs and was high in colored SCLs and lowest in delefilcon-A silicone hydrogel SCL. These results suggest that colored SCLs are not preferred during pollen season.

Comparative Analysis of Adverse Events From a Series of Proof-of-Principle Extended Wear Studies

AIM

A series of proof-of-principle extended wear (EW) contact lens studies were conducted to assess what effect different interventions had on adverse events (AEs). Comparative analysis of AEs across studies was conducted to determine whether some interventions were more effective at reducing inflammatory AEs.

METHOD

Multiple logistic regression analysis of AEs from 30-day EW studies each with a different intervention including (1) nightly replacement (NR) of lenses, (2) morning replacement (MR) of lenses, (3) instillation of prophylactic antibiotic drops (AB) each morning/evening, (4) daily lens cleaning (LC) each morning. All studies conducted at the same site using same lens type (lotrafilcon A) and EW schedule.

RESULTS

Comparison of the different interventions to the individual control groups showed no difference in significant corneal infiltrative event (CIE) or mechanical events. Replacing lenses nightly, during an EW schedule, had the highest incidence of significant CIEs (4.9% [NR] vs. 2.5% [MR] vs. 1.8% [AB] vs. 0% [LC]); however, adjusted logistic regression analysis of the combined control data compared with the individual interventions showed no difference in significant CIEs (P=0.086) or mechanical AEs (P=0.140).

CONCLUSIONS

Replacing lenses each night seemed to be inferior compared with the other interventions of replacing lenses each morning, daily lens cleaning, and daily antibiotic drop instillation during EW. The results of the collective studies and additional analysis suggest that overnight wear of contact lenses seems to create an adverse environment that remains, despite the various interventions intended to improve this adverse environment.

Emerging trends in contact lens-related infections

PURPOSE OF REVIEW

This article reviews the literature on past and recent trends in contact lens-related microbial keratitis from bacterial, fungal, and Acanthamoeba infections.

RECENT FINDINGS

Contact lens wear is the most important risk factor for microbial keratitis. Despite increased use of daily disposable contact lens wear, the incidence of bacterial ulcers related to contact lens wear remains high. Overnight contact lens wear is the leading risk factor in contact lens-related bacterial infections. There may be a trend towards increasing antibiotic resistance of Gram-positive bacteria to fourth-generation fluoroquinolones. The incidence of Acanthamoeba and fungal infections, despite resolution of two outbreaks involving multipurpose solutions, are also on the rise.

SUMMARY

Contact lens-related microbial keratitis is rising and may be associated with more severe, vision threatening, infections.