Research Update Issue 25

January 2019

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 …

January 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 25 – January 2019

Presenting to you the first issue of 2019! We begin the new year with diverse topics in the field of contact lenses.

An Australian group highlights the differences between modern daily disposable multifocal soft contact lenses. We include a study that compares the effects of toric vs spherical lenses on visual performance. Another examines the relationship between water content and silicon content of silicone hydrogels. And a report from Ghana warns of microbial contamination of fluorescein solutions in multiple-use bottles.

Spanish researchers find that keratoconus onset has an impact on the whole anterior segment. Among contributions to a special issue on scleral lenses, a European group looks at how the anterior eye surface is affected by short-term miniscleral contact lens wear. Finally, we include a study that explores whether orthokeratology has a dose-response effect on axial length growth and reduces the interocular difference in axial length in anisomyopic children.

Happy reading!

The IACLE Education Team
Journal reviewed in this issue
JOURNAL VOLUME AND ISSUE NUMBER
Optometry and Vision Science 95:12, 96:1
Eye & Contact Lens 45:1
Clinical and Experimental Optometry 102:1
Contact Lens & Anterior Eye 41:6,
42:1 (Scleral Lens Special Edition)
 MULTIFOCALS

Visual performance of daily disposable multifocal lenses
Sha et al recruited 72 presbyopes to this prospective, randomized, double-blind, crossover clinical trial. Three daily disposable simultaneous-vision multifocal soft lens types were fitted according to manufacturers’ guidelines and worn for 1 week. High- and low-contrast visual acuities were measured. Subjective performance was assessed (1-10 scales) for clarity, ghosting, driving vision, vision stability, ease of focusing, overall vision satisfaction and ocular comfort. BioTrue had better distance performance than near, whereas 1-Day Acuvue Moist performed conversely. Dailies AquaComfort Plus performed reasonably overall.

Optom Vis Sci 2018;95:12 1096-1104. Click here for abstract

 TORICS

Effect of toric vs spherical CLs on vision and eyestrain
In this subject-masked, randomized, cross-over study, Berntsen et al compared the effect of toric vs spherical soft contact lenses on objective measures of visual performance. Current soft CL wearers with -0.75 to -1.75D astigmatism in each eye were binocularly fitted with daily disposable toric and spherical CLs. High and low-contrast visual acuities were measured. Electromyography of the orbicularis oculi muscle was used to evaluate eyestrain. Toric CLs provided improved objective measures of vision in low-to-moderate astigmats.

Eye & Contact Lens 2019;45:1 28-33. Click here for full text

 MATERIALS

Silicone hydrogels: silicon, fluorine and water content
Dupre & Benjamin examined the relationship between water (W) content and silicon (Si) content of silicone hydrogel (SiHy) CL materials. SiHy materials were obtained from 16 CL brands. Fluorine (F) content was included in the analysis for the three materials containing a fluoropolymer. A fundamental negative linear relationship exists between Si and W contents for SiHys above 35% W content that is followed when F content and hydrogel coatings are empirically added to the analysis below 35% W content. The relationship between (Si+F) and W seems to be based on composition rather than structure of available SiHys.

Eye & Contact Lens 2019;45:1 23-27. Click here for abstract

 LENS CARE

Microbial contamination of multiple-use fluorescein
To investigate the possible microbial contamination of fluorescein sodium dye solutions used in eye clinics in Ghana, Kyei et al collected 21 samples of multiple-use fluorescein ophthalmic solutions from clinics (in-use) and 18 unopened bottles (yet to be used) from the same facilities. The solutions were inoculated in different culture plates. Microbial growth was identified using standard techniques. Positive cultures were recorded for all 21 multiple‐use bottles. Multiple-use bottles of fluorescein solution were contaminated with clinically important strains of bacteria and fungi.

Clin Exp Optom 2019;102:1 30-34. Click here for abstract

 KERATOCONUS

Anterior chamber parameters in keratoconus
Mas-Aixala et al investigated whether structural changes in keratoconus are predominantly corneal, limbal/scleral, or a combination of both, and possible differences between anterior segment meridians. A total of 84 eyes with keratoconus and 49 healthy eyes were included. Anterior chamber depth from the endothelium and corneal thickness, anterior chamber depth and sagittal depth (SAGT) from the epithelium, and distance from the end-point of SAGT to the anterior surface of the lens were measured. Keratoconus onset has an impact on the anterior segment as a whole, not only on corneal structures.

Cont Lens Anterior Eye 2018;41:6 538-541. Click here for full text

 SCLERAL LENSES

Anterior eye surface changes after miniscleral wear
To quantify the effect of short-term miniscleral CL wear on the anterior surface, Consejo et al fitted12 healthy subjects with a highly gas-permeable,16.5 mm diameter miniscleral worn for a 5h period. Topography-based corneo-scleral limbal radius estimates were derived from height measurements. Elevation differences in corneal and scleral regions were calculated and sclero-conjuctival flattening within different sectors analysed. A relatively short period of optimally fitted miniscleral lens wear in healthy eyes alters corneo-scleral and sclero-conjuctival topography but, on average, no significant corneal shape changes were found.

Cont Lens Anterior Eye 2019;42:1 70-74. Click here for full text

 ORTHOKERATOLOGY

OrthoK and axial elongation in anisomyopic children
This retrospective, cohort study was conducted by Zhang & Chen to compare the effect of ortho-k on axial length elongation between the fellow eyes of anisomyopic children. Myopic children were categorised into four groups (n=49 in each group): anisomyopic ortho-k, high-isomyopic ortho-k, low-isomyopic ortho-k and anisomyopic spectacles (control). Axial length was measured at baseline and at 1 and 2-year visits. Axial length elongation and interocular difference in axial length were compared. Ortho-k could reduce the amount of anisomyopia in children primarily through stronger myopia control in the more myopic eye.

Optom Vis Sci 2019;96:1 43-47. Click here for abstract

For more information on Research Update visit www.iacle.org.

Research Update Issue 24

December 2018

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 

December 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 24 – December 2018
 
It gives us great pleasure to present the last issue of 2018. The ‘epidemic’ of myopia continues to be an important topic. In this issue, we include a review of the nature vs nurture debate on myopia prevalence. Another review covers various aspects of myopia and myopia control interventions.

US researchers attempt to help practitioners and educators better understand the characteristics of contact lenses and the components of lens care solutions. We report on a study that evaluates a proposed protocol for testing the efficacy of multipurpose solutions against Acanthamoeba. And a group from Australia assesses how well currently available daily disposable soft lenses have achieved the goal of replicating non-wearer experience. Finally, we end the year with a look at patient and prescriber perceptions of contact lenses as a potential ocular drug delivery system.

Wishing you happy holidays and a very happy 2019!

The IACLE Education Team
 
 
 
Journal reviewed in this issue  
  JOURNAL VOLUME AND ISSUE NUMBER
  Clinical and Experimental Optometry 102:1, Early view
  Eye & Contact Lens 44:6
  Optometry and Vision Science 95:12
  Contact Lens & Anterior Eye Article in press
 
 
 
 
 
 MYOPIA
 

Is the nature vs nurture debate finally over?
In this review, Morgan & Rose address the question raised by the current epidemic of myopia: does school myopia appear in individuals with particular genetic backgrounds, or in those exposed to specific environmental conditions? Kepler linked myopia to education over 400 years ago. But it was often argued this association could result from self-selection of academic pathways or near work-intensive occupations by genetically myopic people. Since then, the emphasis has shifted from environment to genetics and back again. Current evidence suggests environmental factors have played a major role in the myopia epidemic, while genetic factors have not.

Clin Exp Optom 2018;102:1 3-17. Click here for full text

 
 
 
 
 
 MYOPIA
 

Review of myopia and orthokeratology
Cho & Tan review important aspects of myopia such as prevalence in children, age of onset, progression rate, associated ocular diseases, mechanism of progression, orthokeratology – its safety and effectiveness – future directions for myopia control and combined treatments. Several studies have shown orthokeratology to be effective in slowing axial elongation and it is a well-accepted treatment, particularly in East Asia. In the near future, a greater demand for effective prophylaxis against childhood myopia is envisaged. A combined treatment of orthokeratology and atropine may have great potential to maximize the effectiveness of myopia control interventions.

Clin Exp Optom 2018; Oct 31. DOI: 10.1111/cxo.12839. [Epub ahead of print]. Click here for abstract

 
 
 
 
 
 LENS CARE
 

Lens care solutions and contact lens discomfort
To understand the impact of solutions on contact lens discomfort, Kuc & Lebow reviewed the published literature. Practitioners should prescribe by pairing the ideal lens material with the appropriate solution. Solution-related corneal staining has been widely studied, yet more research is needed to link the findings to discomfort and increased risk of corneal infection. Understanding individual solution components, antimicrobial and cleaning abilities, and potential solution complications will make the selection easier for traditional daily wearers.

Eye & Contact Lens 2018;44:6 355-366. Click here for abstract

 
 
 
 
 
 LENS CARE
 

Protocol for testing MPS against Acanthamoeba
Fedorko et al used Acanthamoeba castellanii and Acanthamoeba polyphaga and four multipurpose solutions (MPS) with different biocidal agents to evaluate the reproducibility of a proposed protocol for disinfection efficacy. Testing in triplicate and duplicate demonstrated the reproducibility of the protocol both within each laboratory and between the laboratories. The authors conclude this a well-controlled and reproducible procedure that can effectively evaluate the efficacy of MPS against Acanthamoeba trophozoites, although some variability was observed when testing the cyst stage.

Eye & Contact Lens 2018;44:6 367-371. Click here for abstract

 
 
 
 
 
 
 DAILY DISPOSABLES
 

 
Measuring CLs against non-wearer benchmarks
To assess comfort, vision and adverse events in CL wearers relative to spectacle wearers and emmetropes, Lazon de la Jara et al retrospectively analysed seven studies. Five studies involved daily disposable CL wear and had identical inclusion/exclusion criteria, one enrolled full-time spectacle wearers with no prior history of CL wear, and one enrolled emmetropic non-CL wearers. Vision quality and comfort were assessed at the start and end of the day. Corneal infiltrative events were recorded. Comfort and vision with some contemporary daily disposables were indistinguishable from the experience of non-wearing emmetropes.

Optom Vis Sci 2018;95:12 1088-1095. Click here for full text

 
 
 
 
 
 NEW APPLICATIONS
 

Acceptance of CLs for ocular drug delivery
In this cross-sectional survey, Ghazal et al investigated patient acceptance and perceptions of healthcare professionals (HCPs) of the use of CLs as a method for ocular drug delivery. A majority of patients and HCPs showed acceptance of the use of CLs as part of an ocular drug delivery system. The main benefit related to their potential to offer long duration of action. Half of HCPs were not aware of CLs as an ocular drug delivery method. The main reservations were related to cost, ease of use and risk of infection.

Cont Lens Anterior Eye 2018; Nov 13. DOI: 10.1016/j.clae.2018.10.023. [Epub ahead of print]. Click here for full text

 
 
 
 
For more information on Research Update visit www.iacle.org.