Adhesion of Pollen Particles to Daily Disposable Soft Contact Lenses

Comparison of comfort and tear stability with two novel silicone-hydrogel daily disposable contact lenses

BACKGROUND

The surface wettability of soft contact lenses (SCLs) affects the wearing comfort. Verofilcon A is a daily disposable silicone hydrogel contact lens with SMARTSURFACE® technology, ensuring high surface wettability.

PURPOSE

To evaluate tear stability on the surface of verofilcon A and narafilcon A SCLs and correlate these findings with clinical parameters and patients' discomfort.

METHODS

Sixty-two SCL wearers (124 eyes) with SCL discomfort were randomly assigned to use narafilcon A (control SCL) and verofilcon A for 2 weeks each by crossover. The noninvasive tear break-up time (NIBUT) of the naked eye at baseline and pre-lens NIBUT (PL-NIBUT) of the SCL surface after 2 weeks of using each SCL were measured using the DR-1α® dry eye observation device. Corneal superficial punctate keratopathy (SPK) (0-3) and conjunctival hyperemia (0-3), and comfort level of SCL wear (1-10) were also evaluated.

RESULTS

NIBUT and PL-NIBUT values were 4.6 ± 2.3 s for the naked eye, 6.6 ± 6.6 s for narafilcon A, and 11.3 ± 3.5 s for verofilcon A. verofilcon A had significantly higher PL-NIBUT than the naked eye and narafilcon A (p < 0.05). SPK (0.16 ± 0.48 vs. 0.00 ± 0.00, p < 0.01) and conjunctival hyperemia (1.15 ± 0.82 vs. 0.49 ± 0.50, p < 0.01) scores were lower when wearing verofilcon A than narafilcon A. The ocular comfort score of wearing SCLs was higher with verofilcon A than with narafilcon A (8.7 ± 1.8 vs. 9.8 ± 0.5, p < 0.01). The ocular comfort score for wearing verofilcon A was higher, regardless of the baseline NIBUT.

CONCLUSION

The results of this study showed a consistent surface-wetting advantage of verofilcon A in patients with ocular discomfort. verofilcon A was used comfortably in patients with low NIBUT scores at baseline. The findings suggest that verofilcon A is recommended for SCL wearers experiencing SCL-related dry eye symptoms and discomfort.

Physical Properties and Interaction With the Ocular Surface of Water-Gradient Contact Lenses

ABSTRACT

Since the introduction of silicone hydrogel contact lenses, many silicone-hydrogel materials have been produced, including water-gradient contact lenses with a silicone hydrogel core and a thin hydrogel outer layer (e.g., delefilcon A, verofilcon A, and lehfilcon A). Their properties have been investigated in various studies assessing both the chemical-physical characteristics and the comfort, but the overall picture is not always consistent. In this study, water-gradient technology is reviewed by looking at basic physical properties both in vitro and in vivo and at the interaction with the human ocular surface. Surface and bulk dehydration, surface wetting and dewetting, shear stress, interaction with tear components and with other environmental compounds, and comfort are discussed.

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.