Soft toric contact lens wear improves digital performance and vision-A randomised clinical trial

2022 Glenn A. Fry Award lecture: Enhancing clinical assessment for improved ophthalmic management

ABSTRACT

Detailed clinical assessment is critical to allow sensitive evaluation of the eye and its management. As technology advances, these assessment techniques can be adapted and refined to improve the detection of pathological changes of ocular tissue and their impact on visual function. Enhancements in optical medical devices including spectacle, contact, and intraocular lenses have allowed for a better understanding of the mechanism and amelioration of presbyopia and myopia control. Advancements in imaging technology have enabled improved quantification of the tear film and ocular surface, informing diagnosis and treatment strategies. Miniaturized electronics, large processing power, and in-built sensors in smartphones and tablets capacitate more portable assessment tools for clinicians, facilitate self-monitoring and treatment compliance, and aid communication with patients. This article gives an overview of how technology has been used in many areas of eye care to improve assessments and treatment and provides a snapshot of some of my studies validating and using technology to inform better evidence-based patient management.

Optical Quality and Visual Performance With Different Toric Contact Lens Designs

OBJECTIVES

To evaluate the optical quality of different toric contact lens (CL) designs and compare their on-eye visual correction performance.

METHODS

Twenty soft CL wearers aged 20 to 39 years were enrolled. Two daily disposable silicone-hydrogel toric CLs were tested: the "Eyelid Stabilized Design" (ESD-CL) and prism-ballast design (PB-CL); a spherical daily disposable silicone hydrogel CL (spherical CL) was used as a control. On-eye performance was compared for corrected distance visual acuity (CDVA), astigmatism, and ocular higher-order aberrations (HOAs); astigmatism and ocular HOAs were measured with a wavefront sensor. The subjective quality of vision, rated for "blurred vision" and "double vision," lens rotation, and fitting were also compared.

RESULTS

The ESD-CLs, PB-CL, and no-CL provided better CDVA than spherical CL ( P <0.05). Compared with spherical CL and no CL, PB-CL and ESD-CLs caused significantly lesser astigmatism ( P <0.05). Coma was significantly lesser with ESD-CLs than that with PB-CL ( P <0.05); total HOAs did not differ among the four conditions. The subjective ratings for blurred and double vision were significantly lower with ESD-CLs than those with spherical CL ( P <0.05).

CONCLUSIONS

Toric CLs provide a better CDVA than spherical CLs. However, differences in coma and subjective symptoms may occur because of the design of toric CLs.

Clinical performance and Willingness To Pay for soft toric contact lenses in low and moderate astigmats

PURPOSE

To determine clinical performance and the 'Willingness To Pay' for toric vs. spherical soft contact lenses in an astigmatic population.

METHODS

In the clinical study, subjects with binocular low to moderate astigmatism (-0.75DC to -1.50DC) wore pairs of soft toric (Biofinity toric) and spherical (Biofinity) contact lenses in random sequence. Visual acuity (high and low contrast, monocular and binocular), subjective comfort and subjective vision were recorded. In the economics study, first subjects who had participated in the clinical study were presented with a series of randomised economic scenarios in order to determine their Willingness To Pay a premium (i.e. an increase) for toric lenses. Then, a similar set of scenarios were presented to a much larger group of online respondents and again, Willingness To Pay was established.

RESULTS

For the four measures of visual acuity, the Biofinity toric lens out-performed the Biofinity spherical lens by 0.6 to 1.1 lines.. Subjective vision performance was statistically significantly better with the toric lens for the distance task only. Comfort scores were not significantly different. Similar findings for Willingness To Pay were established for the clinical subjects and for the online respondents. The Willingness To Pay premium (additional fee) for a monthly supply of toric lenses (over spherical lenses) was between £13 and £16, if a toric lens provides better vision and similar comfort, as shown in the clinical study.

CONCLUSION

Consumers are willing to pay a monthly premium of around 50% to benefit from the typical experience of better vision and similar comfort for toric vs. spherical lenses. The level of additional cost for toric lenses compared to their spherical equivalents is less than this in the market, so eye care professionals should consider that toric lenses are delivering a greater clinical return than anticipated by wearers for the relatively small increase in price.