Wearable Dark-adaptometer in Normal Adult Healthy Volunteers

Evaluation of a Novel Wearable Light-emitting System for Measuring Dark-adaptation Thresholds in Normal Adult Healthy Volunteers

Conventional dark-adaptometers are unsuitable as a mass screening tool due to their high cost, lack of easy portability, need of trained staff and a totally dark room to be operated, arbitrary testing procedures, associated time waste in clinic and patient burden to mention a few. Consequently, dark adaptometers are not routinely used as clinical tools for retinal diagnosis and monitoring despite the inherent benefits over other visual electrophysiology equipment such as the ERG system, whose cost and features may often be surplus to optometrists' requirements.

This trial will assess the dark-adaptometry testing performance of a novel light-emitting system by generating full dark-adaptation threshold functions in normal adult healthy volunteers.

The novel system has been proposed to overcome the issues associated with current instrumentation; it is semi-automatic and easy to use without the need of any skilled operator.

It is envisaged that this system could spread the practice of dark-adaptometry testing and its adoption by high-street optometrists. This will allow diagnosing a number of retinal pathologies more quickly and more reliably that, faced with an ageing population, represents a major asset to the Health Community and the NHS.

This trial will involve 20 healthy volunteers, distributed in equal number in 2 groups of 18-40 and 50-70 years old, respectively. Proven the good health and eye condition of the participants, one of their eyes will be randomly-allocated and undergo dark-adaptometry testing 3 times on separate days within 3 weeks.

Testing will clarify whether by using the novel system it is possible to reproduce state-of-the-art threshold measurements as good or better than those produced by commercially-available dark-adaptometers. Threshold measurements in the elderly will be compared with literature data adjusted to exclude aged crystalline lens and pupillary miosis contributions. Data variability and system usability will be also assessed.

Study Overview

• Status: Completed
• Conditions: Photoreceptor Sensitivity Thresholds
• Intervention / Treatment: Device: Dark Adaptometer

Detailed Description

All details elsewhere in the documentation

• Study Type: Observational
• Enrollment (Actual): 20

Contacts and Locations

Study Locations

• United Kingdom
  • Merseyside
    • Liverpool, Merseyside, United Kingdom, L78TX
      • University of Liverpool

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Healthy adult volunteers with no prior/current eye problems or family history of genetic eye diseases and good general health.

Description

Inclusion Criteria:

• Refractive error: ≤ ±5 dioptres spherical (myopia/hyperopia) equivalent; ≤ 3 dioptres cylinder (astigmatism) equivalent.

Exclusion Criteria:

• Subjects not in age range and/or unable to fully understand the informed consent and/or unable to comply with study procedures.
• Self-reported history of depression, lack of sleep, psychiatric disorders, or neurological diseases such as Alzheimer's and Parkinson's disease.
• Self-reported history of diabetes, stroke, or multiple sclerosis.
• Self-reported hypovitaminosis A, alcoholism, liver or intestinal disease, malabsorption, protein calorie malnutrition, or sickle cell anaemia.
• Use of psychoactive drugs (including lithium salts for mood stabilisation).
• Use of dietary intake of ascorbic acid, vitamin A, B, E or other antioxidant supplements in the last two weeks.
• Recurrent practice of activities that expose the retina to ultra-violet radiation such as sailing, fishing, sunbathing or tanning saloons.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Young adults (18-40); Healthy adult volunteers, aged between 18 and 40, with no prior/current eye problems or family history of genetic eye diseases and good general health.	Device: Dark Adaptometer
Older adults (50-70); Healthy adult volunteers, aged between 50 and 70, with no prior/current eye problems or family history of genetic eye diseases and good general health.	Device: Dark Adaptometer

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time to Rod-cone Break (RCB)	RCB (time) values were determined by recording the time required for the participant to observe a light stimulus of a particular luminosity. Participants viewed the light stimuli without their optical correction. These consisted of a white (λpeak = 464 nm; chromaticity coordinates - 2° observer: x = 0.269, y = 0.324) circular test target of 0.255 mm radius, forming a visual angle of around 33°. Participants were asked to press a response button on the handheld joystick when the test target was visible and had 750 ms to make a response after target onset. Target intensity started at approximately 4.865 cd*m-2. Light stimuli were presented approximately every 2.6 s for a duration of 150 ms each. If the subject under test did not respond to the stimuli, the target intensity remained at the same initial level of approximately 4.865 cd*m-2 until the subject responded. If the subject reported perception of the light stimulus within the response window, the luminance was reduced by 0	40 minutes
Absolute Threshold	Rod sensitivity (absolute threshold luminance) values measured in cd*m-2	40 minutes
Absolute Threshold Time	Time taken to reach absolution threshold measured in minutes	40 minutes

Collaborators and Investigators

• Sponsor: University of Liverpool
• Investigators: Principal Investigator: Rachel L Williams, PhD, University of Liverpool

Study record dates

Study Major Dates

• Study Start: September 1, 2016
• Primary Completion (Actual): May 1, 2018
• Study Completion (Actual): July 1, 2018

Study Registration Dates

• First Submitted: January 27, 2016
• First Submitted That Met QC Criteria: February 1, 2016
• First Posted (Estimated): February 4, 2016

Study Record Updates

• Last Update Posted (Estimated): July 1, 2024
• Last Update Submitted That Met QC Criteria: June 19, 2024
• Last Verified: June 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Immune System Diseases; Hypersensitivity
• Other Study ID Numbers: UoL001185