Research Update

Research Update Issue 29

IACLE - International Association of Contact Lens Educators
May 2019  
Welcome to our monthly research update
Research Update is a resource available exclusively to IACLE and BCLA members to support your teaching and practice. Each month we send you a summary of some of the interesting findings appearing in peer-reviewed journals that month. Our aim is to help you keep up to date with the latest contact lens and anterior eye research, and to locate articles when you want to know more about a particular topic.
More information on Research Update and how to use it in your contact lens teaching here. Access archived issues via Member Login under Research.
Issue 29 – May 2019
We begin with the most burning issue of the day: myopia control. A meta-analysis assesses the benefit of outdoor activities on myopia onset and myopic shift among school-aged children. Another study examines the impact of contact lens optical design on accommodative behaviour of children.

Two Turkish studies are reviewed this month. One examines the effect of pregnancy on the lacrimal system through tear osmolarity measurement and the Schirmer test. The other evaluates the effects of different contact lens replacement schedules and materials on the ocular surface and tear function. 

A team from China tries to introduce virtual simulation and 3D printing technology to the teaching of contact lens fitting. We include a study that compares the biocidal efficacy of hydrogen peroxide solutions with and without a novel wetting agent. And finally, scientists from Australia explore the link between subjective vision responses and willingness to purchase simultaneous-image contact lenses in presbyopes.

Happy reading!

The IACLE Education Team
Journal reviewed in this issue  
  Optometry and Vision Science 96:4
  Ophthalmic & Physiological Optics 39:3
  Contact Lens & Anterior Eye 42:2
  Cornea 38:5
  Eye & Contact Lens 45:3
Outdoor activities and myopia control
To investigate the protective effect of outdoor activities in myopia control, Deng & Pang conducted a meta-analysis of five prospective intervention clinical studies. Three outcomes were used to assess the benefit of intervention: relative risk, difference in myopic shift rate, and difference in axial elongation rate. The authors found an overall protective effect against myopic shift and axial elongation with outdoor activities. However, the overall treatment sizes for both outcomes (0.13D/year and 0.03mm/year) were small and clinically nonsignificant.

Optom Vis Sci 2019;96:4 276-282. Click here for abstract
Accommodation and myopia control with a soft CL design
Cheng et al evaluated the impact on accommodation and convergence in children wearing investigational soft contact lenses with positive spherical aberration designed for myopia control. Post-hoc analysis was conducted on data from 109 subjects aged 8-11 years from a single-site, 1-year, prospective, randomised, controlled, double-masked clinical trial. The soft lens design resulted in an apparent decrease in accommodation. Reduced accommodative response correlated with greater myopia progression. 

Ophthalmic Physiol Opt 2019;39:3 162-171. Click here for abstract
Pregnancy and tear osmolarity
To examine the influence of pregnancy on tear osmolarity and symptoms of dry eye, Duran & Güngör performed this prospective case-control study among 60 women (30 pregnant and 30 non-pregnant) with no ocular or systemic disease. Tear osmolarity measurement with the TearLab system and tear function test Schirmer 1 were carried out on one, randomly chosen eye of each participant. Tear osmolarity and Schirmer values decreased significantly towards the end of pregnancy, suggesting a decrease in both test results may have a protective role in the ocular surface during pregnancy.

Cont Lens Anterior Eye 2019; 42:2 196-199. Click here for full text
Which lens replacement schedule causes less damage?
To evaluate the effects of different contact lens (CL) replacement schedules and materials on the ocular surface and tear function, Muhafiz et al recruited 71 neophyte subjects to this prospective study. Subjects were divided into three groups and fitted with three different types of CLs: daily disposable hydrogel, daily disposable silicone hydrogel and reusable silicone hydrogel. Tear function tests and inflammatory cytokine levels were evaluated before and after CL use. Wear of daily disposable CLs can be considered to cause less damage to the ocular surface and less increase in proinflammatory cytokines.

Cornea 2019;38:5 587-594. Click here for abstract
3D printing to simulate RGP lens fitting
To introduce a new approach to simulating the fitting process of rigid gas-permeable (RGP) contact lenses using 3D printing technology, Zhao et al created a hemispherical or parabolic 3D model using 3D Builder or Tinkercad software. A solid model was printed using a 3D printer and used to simulate RGP lens fitting. Models were tested for their ability to simulate common corneal morphologies. 3D printing technology can be applied in the simulation of RGP contact lens fitting, which may become a new teaching method in optometry.

Cont Lens Anterior Eye 2019;42:2 165-169. Click here for full text
Biocidal efficacy of hydrogen peroxide with wetting agent
Gabriel et al compared the antimicrobial effects of a 3% hydrogen peroxide (H2O2) solution and a solution consisting of the 3% H2O2 solution plus a novel wetting agent, polyoxyethylene-polyoxybutylene (EOBO-21). Three lots of each solution were tested against five compendial microorganisms required by the Food and Drug Administration and International Organization for Standardization, and other clinically relevant microorganisms. The addition of EOBO-21 to enhance lens wettability had no impact on antimicrobial efficacy.

Eye & Contact Lens 2019;45:3 164-170. Click here for abstract
Vision and purchase of simultaneous image CLs
Jong et al retrospectively analysed visual acuity (VA) measurements and subjective responses of 141 participants from two randomized, masked, crossover, dispensing trials. The purpose was to investigate the relationship between VAs, subjective vision ratings, and willingness to purchase simultaneous-image contact lenses in presbyopes. Subjective vision ratings were a better indicator of simultaneous-image contact lens performance than VA and hence should be used to evaluate performance rather than VA alone.

Optom Vis Sci 2019;96:4 283-290. Click here for abstract
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