Building a Database of Results From People Without Eye Problems
Condition: Glaucoma
MeSH terms: Glaucoma
Study type: Observational [Patient Registry]

Summary: 
      The purpose of this study is to build a database of results from a new test that measures
      contrast sensitivity (the Spaeth-Richman Contrast Sensitivity Test (SPARCS)). Contrast
      sensitivity is an important part of your ability to see. When contrast sensitivity decreases,
      you are less able to see objects and detect motion. For instance, if you have decreased
      contrast sensitivity, you might be less able to read, see in the dark, drive, hit a ball, or
      walk safely. Decrease in contrast sensitivity leads to a decrease in quality of life.
    

Detailed description: 
      Objective: To build a normative database for the Spaeth / Richman Contrast Sensitivity Test
      (SPARCS).

      Background: Patients with glaucoma have diminished contrast sensitivity. SPARCS is a novel
      test designed to determine the contrast threshold in the central 5 degrees of vision as well
      as each of the 4 peripheral quadrants (superotemporal, superonasal, inferotemporal,
      inferonasal). It is performed on a standard computer with at least 1024 x 768 monitor
      resolution. The correct testing distance is 50 cm away from the computer screen. Appropriate
      refractive correction is used. Testing is performed in a room with standardized lighting (85
      cd / m2) and no windows in order to minimize glare and reflections. Testing is performed
      monocularly with the non-tested eye covered by an eye patch. The purpose of this study is to
      build a normative database for SPARCS.

      Study Design: Cross sectional observational study.

      Methods: Healthy volunteers will be recruited from the Wills Eye Institute after obtaining
      informed consent following the principles of the Helsinki Convention. Approximately 320
      people free of ocular disease will be recruited to form a portion of the normative database
      for SPARCS. A goal of 20 subjects per decade of life (10-19, 20-29, 30-39, 40-49, 50-59,
      60-69, 70-79, 80+) for both Caucasians and African Americans will be recruited. Other
      ethnicities will also be recruited, though without specific recruitment goals. Future study
      locations will help diversify the population of the normative database.

      After agreeing to participate in the study, subjects will be assessed to determine if they
      qualify. Potential participants will be asked if they have any known eye diseases or
      decreased vision. Best-corrected monocular visual acuities will be assessed using an ETDRS
      visual acuity chart. A slit lamp examination will be performed to confirm good ocular health.
      Subjects will be excluded if they have any apparent ocular disease that affects visual acuity
      or visual function. For example, people with glaucoma, macular degeneration, or diabetic
      retinopathy will be excluded. Additional exclusion criteria includes: visual acuity 20/40 or
      worse; cataract grade 2 3+ or worse; posterior capsular opacity grade 2 3+ or worse;
      refractive error greater than +5 or -5 diopters; and incisional eye surgery within the prior
      3 months.

      After a person qualifies for the normative database, he or she will then take SPARCS. A
      trained technician will position the patient to the correct testing distance, check room
      lighting, and then explain the test. Subjects will be told to fixate on the central area and
      when ready, click the central area once with a computer mouse. Vertical dark bars will
      briefly appear in 1 of the 5 tested areas on the computer monitor. A subject will then move
      the mouse to the area the image appeared and click it once. When the subject is ready for the
      next image to appear, he or she will click again on the central area. Subjects are also
      instructed to guess where the image appeared if unsure. Vertical square waves of varying
      contrast levels will then continue to appear in a random pattern until threshold has been
      reached for each area. After the testing algorithm has been completed, the test will
      automatically end.

      Each eye of an eligible subject will take the test twice after receiving instructions from a
      technician. The technician will remain in the testing room the first two times SPARCS is
      taken. A half hour later, the subject will then take SPARCS again without instructions from
      the technician and without the technician being present in the room.

      The mean score and standard deviation of each area and the total score will be analyzed for
      age, gender, race, and lens status. Spearman correlations will be used to examine continuous
      variables and Kruskal-Wallis analysis for categorical measures. Test-retest repeatability
      will be assessed using the Coefficient of Repeatability and the Intraclass Correlation
      Coefficient.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Healthy controls with no eye diseases
      
Keywords: Contrast Sensitivity