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Research Update #47

Welcome to Research Update, our monthly summary of important and interesting contact lens-related papers published in the peer-reviewed literature

Myopia control continues to intrigue researchers and academicians alike. This issue begins with a paper on higher order aberrations and axial elongation in combination therapy of atropine with orthokeratology. The COVID-19 pandemic has challenged and disrupted the educational environment. An editorial discusses pandemic-driven innovations in optometric education. 

A study investigates the role of diurnal variation of corneal sensory processing in contact lens discomfort. A Swiss team explores whether lid margin and general pain sensitivity at baseline may help predict subjective comfort of gas-permeable lens wear. Another study looks at the effects of blink type on tear film surface quality.

A group from the US emphasizes the value of routine examination in successful contact lens wear. And finally, we include a paper that compares accommodative micro fluctuations with different lens designs. 

Happy reading!!

The IACLE Education Team

JOURNALS

Journal reviewed in this issue:

Ophthalmic & Physiological Optics  40:6 

Optometry and Vision Science  97:10, 97:11 

The Ocular Surface  18:4  

Clinical and Experimental Optometry  103:6  

Contact Lens & Anterior Eye  43:5

MYOPIA

Combining 0.01% atropine with orthokeratology

In this prospective, randomised study, Vincent et al compared changes in higher order aberrations (HOAs) for photopic and mesopic pupil diameters in children undergoing orthokeratology treatment (OK) or combined 0.01% atropine with orthokeratology treatment (AOK), and the association with axial elongation. Baseline and 6-month data from 25 AOK and 28 OK participants were analyzed. AOK treatment resulted in increased photopic pupil size and HOAs, and significantly less axial elongation compared to OK treatment alone.

Ophthalmic Physiol Opt 2020;40:6 728-737. Read the abstract

CORONAVIRUS

Pandemic-driven innovations in optometric education

As COVID-19 infection rates rose in early 2020, it was clear that significant changes in education were imminent. In this editorial, Twa discusses pandemic-driven changes in delivery of education in the US. Schools were forced to find ways to maintain the continuity of their didactic and clinical training programs in the absence of face-to-face instruction. This drove most didactic courses toward online delivery. In the absence of direct patient-based learning experiences, patient simulations have become increasingly valuable. And, in clinical practice, telehealth started gaining acceptance. 

Optom Vis Sci 2020;97:10 831-832. Read the full text

COMFORT

Diurnal variation of sensory function in CL discomfort

To test the hypothesis that dysfunction of the sensory function and tear secretion underlies the increasing symptoms of discomfort at the end of the day in CL wearers, Situ et al recruited 26 symptomatic and 25 asymptomatic wearers and 15 asymptomatic non-CL wearing controls. Cooling thresholds, symptoms and tear meniscus height (TMH) were measured on each of three measurement days (random order) at different times. Corneal sensitivity and symptoms, but not TMH, increased diurnally irrespective of CL wear in symptomatic CL wearers, revealing the role of neurosensory abnormalities in CL discomfort.

The Ocular Surface 2020;18:4 770-776. Read the abstract 

Pain perception with rigid contact lenses

To explore whether knowledge of lid margin and general pain sensitivity of prospective RGP CL wearers at baseline may help to improve predictability of successful RGP CL wear, Nosch et al recruited 34 volunteers (18-40 years of age). Subjects completed a pain sensitivity questionnaire and relevant clinical tests were performed at baseline and a subsequent visit. The results suggest that lid margin sensitivity may not play an important role in spontaneous RGP CL comfort. Use of the pain sensitivity questionnaire may help select patients who are more likely to show good spontaneous tolerance of RGP CLs.

Clin Exp Optom 2020;103:6 766-771. Read the abstract

TEAR FILM

Blinking and tear film stability

Szczesna-Iskander & Llorens Quintana conducted this experiment to determine to what extent type of blink affects tear-film breakup time, and its assessment using two types of video-keratoscopes and the fluorescein test. In 33 subjects, they considered two different types of blinks: natural (short) and forced (unnaturally prolonged). Objective non-invasive breakup time was estimated using Oculus Keratograph 5M and Medmont E300. The authors found that forced blinks affect the assessment of tear-film stability. Hence, attention should be given to instructing subjects before tear-film breakup time evaluation.

Optom Vis Sci 2020;97:11 954-961. Read the abstract 

EYE EXAMINATION

Routine evaluation in asymptomatic soft CL wearers

To document complications diagnosed when subjectively successful planned replacement soft CL patients are evaluated to renew their existing prescriptions, Chen et al conducted this prospective, cross-sectional, non-interventional study. Asymptomatic soft CL patients who presented at two centers, for routine CL examination to renew existing prescriptions, were evaluated and complications were documented. Over half of the 202 patients (52%) exhibited at least one undiagnosed health complication and, of those, 70% were CL driven. The high complication rate in asymptomatic lens wearers suggests that all CL wearers require routine professional evaluation.

Cont Lens Anterior Eye 2020;43:5 484-488. Read the full text

ACCOMMODATION

Micro-fluctuations in CLs of different designs

Kajita et al conducted this prospective, multi-centre, randomized, cross-over, subject-masked study to compare changes in accommodative micro-fluctuations (AMF) when wearing CLs of two different optical designs. AMF was measured using an auto-refractometer in accommodation analyzer mode for 68 adapted CL wearers aged 25-35 years who wore spherical and aspheric silicone hydrogel lens designs. The authors found smaller changes in AMF when subjects used lenses with aspheric design. CL wearers who frequently use digital devices and are experiencing eye strain may benefit from switching from a spherical design to one that incorporates aspheric optics, they say.

Cont Lens Anterior Eye 2020;43:5 493-496. Read the full text

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© International Association of Contact Lens Educators 2020

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