Research Update

Research Update Issue 20

August 2018

Outdoor light has been debated as an important factor in the onset and progression of myopia. In this issue, we include a vital study on myopia prevention and outdoor light intensity 

August 2018  

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 20 – August 2018
Controlling Myopia Progression: Where Do We Stand Today?

Outdoor light has been debated as an important factor in the onset and progression of myopia. In this issue, we include a vital study on myopia prevention and outdoor light intensity. In another study, a Chinese group compares excimer laser refractive surgery and phakic intraocular lenses (PIOLs) for the treatment of myopia and astigmatism.

An Australian team attempts to understand the role of cohesion, coaggregation and growth in the build-up of biofilm formation of commonly isolated case contaminants. We include a study that ascertains the relationship between scleral asymmetry and corneal astigmatism in both astigmatic and non-astigmatic eyes.

Another paper reviews spectacle prescriptions to determine the prevalence of ametropia and coverage of frequent replacement soft toric contact lenses. And finally, we describe research that measures the effects of two different lens care systems on the integrity of eyelid tissue in silicone hydrogel contact lens wear.

Happy reading!

The IACLE Education Team
Journal reviewed in this issue  
  Ophthalmology 125:8
  Eye & Contact Lens 44:3
  Investigative Ophthalmology & Vision Science 59:7
  Cornea 37:8
  Contact Lens & Anterior Eye Articles in Press41:4

Could artificial lighting be effective in preventing myopia?
In his commentary on a study by Wu et al on myopia prevention and outdoor light intensity in a school-based cluster randomized trial, Morgan examines some important findings. The study reports protection from progression in children who were already myopic at baseline, with reduced myopic shifts and axial elongation. The daily light exposures measured objectively were quite low, with most of the outdoor exposures concentrated at less than 5000 lux. The findings raise two possibilities: the first is that increased time outdoors may slow the progression of myopia; the second is that lower than expected light exposures may be effective, enhancing the possibility of protection with bright light devices.

Ophthalmology 2018;125:8 1239-1250 (Wu et al) and 1251-1252 (Morgan). Click here for study abstract and here for full text of commentary


Excimer laser vs phakic intraocular lenses
To compare excimer laser refractive surgery and phakic intraocular lenses (PIOLs) for the treatment of myopia and astigmatism, Chen et al conducted a meta-analysis of randomized controlled trials (RCTs). From 219 initially identified studies, five RCTs were reviewed including 405 eyes. The range of myopia was 6.00D to 20.00D with up to 4.00DC of astigmatism. On the whole, there was no significant difference in efficacy and complications between the two kinds of surgeries. However, the analysis indicated that PIOLs were safer and more accurate within 12 months of follow-up compared with excimer laser procedures.

Eye & Contact Lens 2018;44:3 137-143. Click here for abstract


Interactions between bacteria from CL cases
Datta et al examined cohesion, coaggregation, and coculture between bacteria commonly isolated from contact lens cases. Staphylococcus epidermidis and haemolyticus, Micrococcus luteus, and Acinetobacter radioresistens (two strains each) were isolated from cases of two asymptomatic wearers. The degree of coaggregation varied between 30% and 54%. The highest coaggregation was seen between A radioresistens 22-1 and S epidermidis 22-1, isolated from the same lens case. Coaggregation, cohesion, and growth promotion may facilitate bacterial colonization of cases, raising the possibility of adding substances to CL disinfecting solutions that could prevent aspects of cohesion or coaggregation.

Invest Ophthalmol Vis Sci 2018;59:7 2729-2735. Click here for full text


Scleral shape and astigmatism
To assess the correlation between the scleral shape and corneal astigmatism, Consejo & Rozema investigated 22 participants: 16 females and six males (11 non-astigmatic and 11 astigmatic), aged from 19 to 36 years. Three-dimensional (3D) corneoscleral maps from both eyes (44 eyes) were acquired using a corneoscleral topographer. In astigmatic eyes, corneal and scleral asymmetry are highly correlated, but both appear independent of each other in non-astigmatic eyes. The findings suggest that astigmatism is not restricted to the cornea but should rather be considered a property of the entire eye globe.

Cornea 2018;37:8 1047-1052. Click here for abstract


Ametropia and coverage of soft torics
To determine the prevalence of ametropia and astigmatism in a clinic population and to estimate the coverage of frequent replacement soft toric lenses, Luensmann et al reviewed and analyzed prescription data from three clinical sites (for patients 14 to 70 years of age) to determine prevalence of ametropia and astigmatism. Of the 101,973 patients, astigmatism in at least one eye was found in 87% of the population, with 37% of the patients exhibiting astigmatism of at least −1.00DC in at least one eye. Currently available frequent replacement soft toric CLs provide coverage for up to 96% of potential patients.

Cont Lens Anterior Eye (2018), Click here for full text


Lens care system and eyelid tissue in SiHy lens wear
Guillon et al compared the effects of a hydrogen peroxide (H2O2)-based lens care solution and a polyhexamethylene biguanide (PHMB) multipurpose solution on the eyelids when used with two different silicone hydrogel (SiHy) contact lenses in a total of 74 symptomatic CL wearers. Hyperemia, papillae and lid margin staining of eyelid tissue were evaluated at enrolment, at dispensing and at 3-months’ follow-up. An H2O2-based lens care solution used with senofilcon A and balafilcon A lenses was better tolerated by eyelid tissues than was a PHMB-based solution and led to a decrease in clinical markers of eyelid inflammation.

Cont Lens Anterior Eye 2018;41:4 362-368. Click here for full text

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