Impact of contact lens type and blinking patterns on tear film stability and halos

Authors:
Bodas-Romero, Julia¹; Romaguera, María¹; Valdes-Soria, Gonzalo ¹; Batres, Laura¹; Carracedo, Gonzalo ¹

1 Ocupharm Research Group, Department of Optometry and Vision, Faculty of Optics and Optometry, University Complutense of Madrid.

The authors of this work express their gratitude for the support provided by CooperVision, Inc.
 

Objective:
To assess the impact of blinking frequency patterns and contact lens type (materials and optical designs) on tear film stability and visible halos. 

Methods:
Twenty non-presbyopic (aged 21–39 years) myopes (spherical equivalents -0.50D to -8.00D and ≤0.75D of astigmatism) were fitted with four types of soft contact lenses (CLs): three single-vision designs (stenfilcon A, senofilcon A, lotrafilcon A) and one multifocal design (MFCL, senofilcon A). Halo size was measured monocularly at 2 metres using the Light Disturbance Analyzer (LDA, BinaryTarget, Portugal) under mesopic conditions. To quantify halo size, subjects fixated on a central 5 mm LED light, while 1 mm peripheral LED lights of low intensity appeared until the subjects could detect them.   Measurements were conducted during free and hold blinking conditions (20 seconds between blinks) with CL and spectacles (baseline). Tear film surface quality (TFSQ), assessed using a 20 seconds dynamic topography, which indicates the tear film stability, with values >0.3 indicating low surface wetting. The statistical analysis was performed using SPSS Statistics V27.0, with p<0.05 considered significant. One-way ANOVA test and Spearman correlation was used to assess the relationship between variables.
 

Results: 
Halo size differences between free and hold blinking were statistically significant for all lenses (p<0.01), with larger halos observed during hold blinking. Compared with stenfilcon A (10.48±2.82mm), halos were significantly larger with spectacles (12.96±3.88mm) and MFCL (12.91±2.93mm) during free blinking conditions (p<0.01).  TFSQ scores were significantly higher with all CLs than with spectacles (p<0.05) but no significant differences were found between the contact lenses (p>0.05). No significant correlation was found between TFSQ scores and halo sizes in hold blinking conditions.
 

Conclusions: 
Lens design and blink frequency significantly influence halo size and visual quality. Despite tear film disruption reducing optical quality, no correlation was found between TFQS levels and halo sizes.