Research Update

Research Update Issue 14

February 2018

In this issue, we continue our quest to understand the effects of soft contact lens wear on the tear film and include a review that summarizes key changes to the tears in CL wear. A group from Japan investigates the relationship between changes in ocular surface temperature and tear film stability 

February 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 14 – February 2018
 
In this issue, we continue our quest to understand the effects of soft contact lens wear on the tear film and include a review that summarizes key changes to the tears in CL wear. A group from Japan investigates the relationship between changes in ocular surface temperature and tear film stability.

From a special issue of Contact Lens & Anterior Eye on New Dry Eye Research – building on the latest TFOS report, DEWS II – we include a study that explores osmolarity, comfort and lid wiper epitheliopathy in CL wear. Proactive contact lens prescribing has been believed to result in converting spectacle wearers to CL users. A group of Indian FIACLEs compares two approaches to proactive prescribing.

We report on a scleral lens study that evaluates turbidity and thickness of the post-lens tear layer and effects on visual quality in patients with keratoconus. Finally, we include research that examines accommodation in early presbyopes fit with a bilateral or unilateral near add.

Happy reading!

The IACLE Education Team
 
 
 
Journals reviewed in this issue  

  JOURNAL VOLUME AND ISSUE NUMBER
 
  Clinical and Experimental Optometry 100:5, 100:6
  Investigative Ophthalmology & Vision Science 59:2
  Contact Lens & Anterior Eye 41:1, Articles in press
  Optometry and Vision Science 95:1
 
 
 
 
 
 TEAR FILM
 

Tear film in soft contact lens wear: a review
Soft contact lens (SCL) wear has the potential to adversely affect the tear film and anterior ocular surface. This review by Downie and Craig summarises current knowledge relating to the effects of SCL wear on the tear film and ocular surface. The review guides the clinician to recommend appropriate management of any tear film abnormalities. It describes a diagnostic approach to assessing tear film and ocular surface health, and includes a tear film lipid layer grading scale. The authors also summarize key changes to the tear film in CL wear and management strategies to improve tear film and ocular surface health.

Clin Exp Optom 2017;100:5 438-458. Click here for full text

 
 
 
 
 
 TEAR FILM
 

Ocular surface temperature and tear film stability
To investigate the association between changes in ocular surface temperature (OST) and tear film stability over soft contact lenses (SCLs), Itokawa et al measured OST of 20 eyes of 20 SCL wearers. Measurements were taken every second for 10s without blinking. Tear film stability was evaluated by non-invasive tear break-up time (NIBUT) and tear interference patterns on the contact lenses (TIPCL). The difference in OST correlated significantly with NIBUT without and with SCL. OST can be used to evaluate tear film stability in SCL wearers.

Invest Ophthalmol Vis Sci 2018;59 771-775. Click here for full text

 
 
 
 
 
 COMFORT
 

Contact lens comfort, osmolarity and lid wiper staining
To explore osmolarity, comfort and lid wiper epitheliopathy in CL wear, Stahl & Jalbert conducted this randomized, cross-over study where two different silicone hydrogel lens types were each worn for 10 days by 20 subjects. Comfort and tear stability decreased and upper lid wiper staining and foreign-body sensation increased with lens wear and were not affected by lens type. Relationships between comfort and CL osmolarity, and between tear osmolarity and tear stability and production, were found. The study could not demonstrate an association between comfort and tear osmolarity or lid wiper epitheliopathy.

Cont Lens Anterior Eye 2018;41:1 110-116. Click here for full text

 
 
 
 
 
 CL PRACTICE
 

Proactive contact lens prescribing
In this prospective, randomized, controlled, multi-centre study, Thite et al evaluated the impact of optometrists’ proactivity on the prescribing of CLs by assigning 60 neophytes each to two groups: conventional proactive recommendation (CPR), where subjects were offered CLs as a mode of vision correction; and the EASE (Enhancing the Approach to Eyewear Selection) approach, where CLs were offered as an aid to spectacle selection. Of these 120 subjects, 53% were prescribed CLs as a mode of vision correction within the 3-month study period. CPR showed a higher conversion rate from CL experience to prescribing than the EASE approach.

Cont Lens Anterior Eye 2018. DOI 10.1016/j.clae.2018.01.001. Click here for full text

 
 
 
 
 
 SCLERAL LENSES
 

Scleral lenses and tear turbidity
This experimental, short-term study was conducted by Carracedo et al to evaluate the turbidity (cloudiness or haziness) and thickness of the post-lens tear layer and its effect on visual quality in patients with keratoconus fit with scleral lenses. Distance visual acuity (VA), contrast sensitivity, pachymetry, post-lens tear layer height and post-lens tear layer turbidity were evaluated with optical coherence tomography in 26 patients before and after lens wear. VA decrease during wear of a scleral lens filled with preserved saline was due to increasing post-lens tear layer turbidity.

Clin Exp Optom 2017;100:6 577-582. Click here for abstract

 
 
 
 
 
 PRESBYOPIA
 

Accommodation in early presbyopes
Almutairi et al examined accommodation behavior, pupil responses, and resultant image quality in early presbyopes fit with either bilateral or unilateral (monovision) near vision adds. Accommodative response and pupil size of 19 subjects were measured with an aberrometer. Subjects were fit with different strategies: bilateral distance, bilateral +2D near add and unilateral +2D near add. Findings suggest many early presbyopes will not adopt an accommodation strategy to optimize image quality with monovision but accommodate to focus the distance-corrected eye.

Optom Vis Sci 2018;95:1 43-52. Click here for abstract

 
 
 
 
 
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