Repeatability and Agreement of Anterior Segment Optical Coherence Tomography (AS-OCT) and Thermography
Condition: Dry Eye Syndromes
MeSH terms: Dry Eye Syndromes
Study type: Interventional

Summary: 
      Dry eye is a common condition that affects vision and quality of life in patients. Dry eye
      clinical research is limited to follow up of disease progression. Currently, most research
      outcomes are based on subjective patient complaints rather than objective assessment of the
      condition. Only few objective measurements for dry eye are available today and this is mainly
      the result of poor repeatability and inaccuracy.

      This current study aims to evaluate 2 new non-invasive imaging techniques suitable for dry
      eye assessment.

      Anterior segment optical coherence tomography (AS-OCT) is an imaging device that has the
      ability to image the tear meniscus of the eye in a safe and non-invasive manner. Image
      analysis can then indirectly determine the tear film volume. Improvements in the image
      resolution of these devices require a study that compares the repeatability and agreement of
      an older (Visante AS-OCT) and a newer instrument (Cirrus AS-OCT) which the current study aims
      to address.

      Another method of evaluating dry eye disease is a novel technique that uses functional
      infrared thermography to measure tear evaporation rate. This study will also establish
      repeatability of measurements of the ocular surface temperature which are used to calculate
      tear evaporation rates.

      Should these methods are found to be repeatable, they can be used in future clinical trials
      as an additional tool to investigate dry eye treatments.
    

Detailed description: 
      Study Objectives and Purpose:

      Part A - AS-OCT repeatability and agreement

        1. The primary purpose of Part A is to compare the repeatability of the Cirrus with the
           Visante AS-OCT imaging system.

        2. The second objective is to identify the level of agreement in the tear meniscus
           measurements taken by the Cirrus and Visante AS-OCT.

      Part B - Tear evaporimetry with functional infra-red thermography

        1. To evaluate the repeatability of Infrared thermography for ocular surface temperature
           measurements that are used for calculation of tear evaporation rates. If this is found
           to be acceptable, it will be correlated to tear meniscus parameters.

        2. To determine whether this method is able to detect temperature changes of the ocular
           surface.

      Study design:

      Part A. Cross sectional study. Part B. Prospective study

      Rationale:

      Part A - AS-OCT repeatability and agreement Repeatability is an important issue in the
      objective assessment of dry eye. While previous studies have compared various methods of
      measuring the tear meniscus, including the use of Visante AS-OCT, current literature lacks
      studies that investigated the Cirrus AS-OCT for assessment of dry eye. With a higher
      resolution, the Cirrus is potentially useful as a non-invasive procedure for objective
      measurements of the tear meniscus.

      Part B - Tear evaporimetry with functional infra-red thermography Current available methods
      to measure of tear evaporation rate have major limitations. This new method, however, is
      non-invasive, has no need for special eye drops or chambers and takes temperature
      measurements very quickly. This method is therefore extremely practical and provides many
      exciting possibilities for future trials.

      Methods:

      Participants and target sample size 40 volunteers from Singapore Eye Research Institute will
      be recruited for this study. Each volunteer will be given a study serial number to ensure
      anonymity.

      20 will participate in the AS-OCT study. 20 will participate in the tear evaporimetry study.

      Part A - AS-OCT repeatability and agreement Two AS-OCT imaging systems, namely Cirrus and the
      Visante, will be tested. All participants undergo acquisition of 2 images by the Visante
      AS-OCT, then 2 images by the Cirrus AS-OCT. Both images will be acquired by the same
      technician.

      Part B - Tear evaporimetry with functional infra-red thermography In total, four pairs of
      thermographic sequences on the ocluar surface temperature from volunteers will be taken.

        1. The volunteer will be seated in front of the thermographic camera and on each eye on
           thermographic sequence will be captured.

        2. After 20 minutes, a second pair of thermographic sequences will be captured.

        3. An eye mask with a temperature of not more than 40 deg C (confirmed by thermometer) will
           be worn by the volunteer for 5 minutes.

        4. A third pair of thermographic sequences will be captured immediately after mask removal.

        5. A fourth pair of thermographic sequences will be captured 1 hour after mask removal.

      Between sequence acquisitions, the volunteer is allowed to move freely in the room. The
      temperature and humidity of the room will be kept constant during measurements.

      Visit schedules:

      Only one examination per ASOCT instrument for Part A is required. For Part B, all
      thermography will be performed on the same day.

      If participants agree to have both ASOCT and tear evaporimetry done, then they will undergo
      Parts A and B. If not, they will be recruited for either Part A or Part B.

      Duration of study: 1 day
    

Intervention name(s): EyeGiene
Intervention type(s): Device
Intervention description(s): The eye mask with a temperature of not more than 40 deg C (confirmed by thermometer) will be worn by the volunteer for 5 minutes.
Other intervention name(s): EyeGiene (Eyedetec Medical Inc., US)
Allocation: Non-Randomized
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Screening
Keywords: Visante AS-OCT; Cirrus AS-OCT; Thermography; Tear evaporation; Tear evaporimetry