Research Update

Research Update Issue 23

November 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 23 – November 2018
The last outbreak of Acanthamoeba infections in US and UK contact lens wearers occurred in the 1990s. In this issue, we include a study that confirms a further outbreak in the UK starting in 2010-2011. Another discusses the challenges faced by the US Food & Drug Administration in developing a standard protocol for disinfection efficacy testing for Acanthamoeba.

Researchers from Canada bring our attention back to hand hygiene and its link to corneal infection and inflammation. A prospective, cross-over study examines the impact of monovision CL correction on reading. And a group of scientists from Spain evaluates light disturbances in children wearing myopia control lenses.

Could early diagnosis of clinical markers of CL discomfort help clinicians set realistic expectations and provide prophylactic management? A team in Australia investigates. And, finally we include a survey that explores current practice in the use of scleral lens therapy.

Happy reading!

The IACLE Education Team
Journal reviewed in this issue  
  British Journal of Ophthalmology 102:12
  Eye & Contact Lens 44:6
  Contact Lens & Anterior Eye Articles in Press
  Scientific Reports (Nature) 8:1
  Optometry and Vision Science 95:11

Acanthamoeba keratitis: UK outbreak and risk factors
To test claims that the UK incidence of Acathamoeba keratitis (AK) may have increased in 2012-2014 and to evaluate potential causes, Carnt et al collected incidence data from January 1984 to December 2016. Case-control subjects were recruited between April 2011 and June 2017. Reusable CL users with AK were recruited retrospectively and prospectively. The outbreak started in 2010-2011 with an incidence 3X higher than in 2004-2009. Risk factors included: Oxipol disinfection, CLs made of group IV materials, poor lens or hand hygiene, and use of CLs while swimming or bathing.

Br J Ophthalmol 2018;102:12 1621-1628. Click here for full text


Disinfection efficacy testing for Acanthamoeba
In this review, Brocious et al discuss the challenges in developing a standard protocol for disinfection efficacy testing for Acanthamoeba. Two distinct life stages (trophozoite and cyst), different growth methods and encystment techniques, and many other parameters that can affect testing outcomes, make it difficult to create a standard protocol. A 2014 workshop noted a 2- or 3-log kill for trophozoites was adequate for disinfection, but more research was needed to establish a criterion for cyst kill. The US Food & Drug Administration has embarked on research to provide a recommended testing protocol for CL care products.

Eye & Contact Lens 2018;44:6 351-354. Click here for abstract


Hand hygiene: corneal infection and inflammation
Fonn & Jones draw attention to public health literature in support of hand washing and how education can influence patients’ hand hygiene behavior. Many CL wearers are not compliant with hand-washing procedures (up to 50% in some reports) and this increases the risk of microbial contamination of CLs, which in turn may increase the risk of developing microbial keratitis and corneal inflammatory events. Education strategies should improve hand-washing behavior, but there is little research to substantiate the claim.

Cont Lens Anterior Eye 2018 Nov 7. DOI: 10.1016/j.clae.2018.10.022. [Epub ahead of print]. Click here for full text


Reading eye movements with monovision
Zeri et al examined the impact of monovision CL correction on reading by recording eye movements (EM) while 15 participants read text passages, and arrays of unrelated words and non-words. Three conditions were compared: baseline (near correction in both eyes), conventional monovision (distance correction in dominant eye, near correction in non-dominant eye), and crossed monovision (reversal of conventional monovision). Monovision did not appreciably alter visual processing when reading meaningful texts but some limited stress of the EM pattern was observed with arrays of unrelated or meaningless items.

Scientific Reports 2018;8:15574. DOI:10.1038/s41598-018-33934-6. Click here for full text


Light disturbance with dual focus contact lenses
In this randomized, controlled clinical trial (MiSight Assessment Study Spain) Ruiz-Pomeda et al evaluated perception of light disturbances (LD) in children wearing Dual Focus (DF) CLs for myopia control compared with children wearing single-vision spectacles (SV). LD was determined at baseline, 12 and 24 months in 74 subjects (41 DF, 33 SV) with a Light Disturbance Analyzer. DF lenses increased monocular light disturbance perception compared with SV. However, this effect decreased over the follow-up time, with a significant binocular attenuation effect.

Cont Lens Anterior Eye 2018 Nov 15. DOI: 10.1016/j.clae.2018.11.006. [Epub ahead of print]. Click here for full text


Predictors of contact lens discomfort
To evaluate the potential for eyelid- and tear film-related clinical markers as predictive factors for diagnosing discomfort in CL wearers, Siddireddy et al conducted this cross-sectional study on 30 subjects. Eyelid signs and tear film characteristics were evaluated during a single visit, and subjects completed the Contact Lens Dry Eye Questionnaire-8 to evaluate ocular discomfort. Clinical signs related to meibomian gland secretions and morphology, tear evaporation, lid-parallel conjunctival folds, and palpebral conjunctival health may successfully predict symptoms of discomfort in CL wearers.

Optom Vis Sci 2018;95:11 1035-1045. Click here for abstract


Current practice in scleral lens therapy
To describe current practice in the use of scleral contact lens therapy, Shorter et al administered an electronic survey to eye care providers. Of 723 respondents, 629 ranked options for management of corneal irregularity and 612 ranked options for management of ocular surface disease. Corneal RGPs were the first option for management of corneal irregularity for 44% of respondents while scleral lenses were the first option for 34%. Scleral lenses rank second only to RGPs for management of corneal irregularity.

Eye & Contact Lens 2018;44:6 372-378. Click here for abstract

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