Evaluation of Different Color Vision Tests in Children
Condition: Color Perception
Study type: Observational

Summary: 
      The purpose of this study is to investigate which clinical colour vision assessment fits best
      for preschool children and school children. The investigators are going to investigate
      children with a known colour vision affecting ocular disease, as well as healthy children
      without colour vision deficiency. The goal is to compare the usability and validity of three
      different clinical tests for colour vision assessment which are already well established in
      adults but not yet in children.
    

Detailed description: 
      Colour vision is an important part of the visual perception. There exist hereditary and
      acquired forms of colour vision deficiency. Hereditary forms affect 8% of males and 0.4% of
      females. Acquired forms can occur due to diseases which affect the retina, optic nerve or
      parts of the brain involved in colour vision such as the optic tract or visual cortex. Early
      diagnosis of colour vision deficiency is especially important in children to provide prompt
      aid through parents, teachers or other persons taking care. Moreover colour vision deficiency
      can be an early sign of beginning and progressive ocular diseases.

      Colour vision assessment is part of standard clinical testing in ophthalmology. In children,
      colour vision assessment can be difficult, as most of the tests were developed for adults.
      The investigators are going to investigate the suitability of some of these tests for
      children. It is planned to investigate 40 children without colour vision deficiency and 40
      children with a known colour vision deficiency. The data collection will take 1 year.

      The study involves an ophthalmologic examination and the assessment of 3 different colour
      vision tests. All examinations are non-invasive, performed once and last in total about 1 to
      1.5 hours. The visual acuity will be assessed by eye charts and refraction measurement
      followed by a slit lamp examination of the front sections of the eye and an optical
      examination of the eyeground. The three coulour vision tests are part of the standard
      repertoire of the Institute for ophthalmology of the University hospital of Zürich. Each
      colour vision test will be performed once as a test run and twice as a study examination. In
      the first test the child is asked to recognize known geometrical figures and pictures on
      charts. The second test involves the recognition of colored caps and the third test is a
      computer-assisted examination where the child should denote the position of a coloured area
      on the screen.

      In the children with a known optical disease there will be performed additionally an optical
      coherence tomography to quantify the disease based morphological changes of the retinal
      layers. Therefore the pupils have to be dilated with the application of specific eye drops
      medication. This can lead to transient decrease of visual acuity for about 2-4 hours. The
      child should not drive a bicycle during this time interval. The principal of Optical
      coherence tomography (OCT) is similar to medical ultrasonics. However in OCT, there are used
      light waves instead of ultrasound waves, which allow an exact examination of the retinal cell
      layers.

      All the examinations performed in this study are standardized procedures at the Institute of
      Ophthalmology of the University hospital of Zürich. No risks or harms are expected in
      relation with the planed examinations. No payment will be asked for the study related
      examinations. Neither for patients nor for their health insurances arise any additional costs
      related to the participation in this study.
    

Intervention name(s): only examination
Intervention type(s): Other
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        80 children (girls and boys) at the age of 3-10 years without (40 children) or with (40
        children) an ocular disease such as maculopathy, opticopathy or amblyopia will be included.
        Probands and patients are recruited from consultations at the eye clinic of the University
        hospital of Zürich. The ophthalmologic care is provided independently of the patient's
        decision whether to participate in the study or not. This decision is the own free will of
        the patient and his or her parents.