• By Galton Vasconcelos, MD; Luciene C. Fernandes, MD
    Low Vision

    Introduction

    In the practice of eye care, the World Health Organization (WHO) defines a low-vision child as "a child who has impairment of visual functioning even after treatment and/or standard refractive correction, and has a visual acuity (VA) of less than 20/60 (6/18) to light perception, or a visual field of less than 10 degrees from the point of fixation, but who uses, or is potentially able to use, vision for planning and/or execution of a task."1

    Low vision can restrict life experiences, speed of working, motor development and orientation, and skill in practical subjects. It can affect the child's education as well as social and emotional development.1

    The WHO suggests that low-vision care should be offered at primary, secondary, and tertiary levels. At the primary level, community-based workers identify and refer people with low vision to a higher level of service and advice on environmental modification. At the tertiary level, a team of trained professionals offer advanced care in a specially developed low-vision clinic or hospital. The critical interface between these 2 levels is the secondary level of care, a district-level low-vision care.1,2

    It is important to consider population density, geographical coverage, and accessibility while planning for low-vision care.

    Levels of Low-Vision Care for Children

    Primary Level

    At the primary or community level, community-based workers identify and refer the child with low vision to a higher level of service and advice on environmental modification and optical interventions.

    It is recommended that primary level care be able to meet the needs of 30% of the low-vision population.3

    Human Resources

    A child is assessed by a pediatrician or family doctor who is responsible for care of the child at birth as well as nurses, ophthalmic nurses, community-based workers, and other mid-level personnel.1,2

    Purposes

    • Identify children who might have low vision
    • Refer them for diagnosis, prognosis, and good refraction
    • Refer older children who have useful vision to low-vision services at the secondary level
    • Refer young children with complex needs to the tertiary level
    • After diagnosis, refraction, and referral for low-vision care, advice on optical interventions and environmental modifications. Later, the child should be referred for educational support and community-based rehabilitation if needed1,2

    Relevant activities should be integrated with existing maternal and child health programs, immunization programs, and other community-directed health services. Treatment of simple eye infections, prevention of corneal trauma, and immunization are best managed at the primary level.

    Recommendations for Community and School Screening Programs

    At the primary care setting, the American Academy of Ophthalmology (AAO), the American Academy of Pediatrics (AAP), and the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) recommend vision screening prior to kindergarten. They also recommend that a comprehensive eye exam be performed whenever questions arise about the health of the visual system of a child at any age. In addition, even in the absence of specific signs or symptoms, they recommend that infants and children be routinely screened for vision problems as follows and that any child who does not pass one of more of these screening tests have a comprehensive ophthalmological examination.

    Many serious ocular conditions are treatable if identified through screening during the preschool and early school years. Many of these conditions are associated with a positive family history. Therefore, additional emphasis should be directed to screening high-risk infants and children, and when necessary, screeners should readily refer such children to an ophthalmologist for a comprehensive eye evaluation.4,5

    Secondary Level

    At the secondary or district level, low-vision care is aimed mainly at older children who want to access print or perform tasks that require good near vision.2,6 The WHO has produced estimates of 50% of the low-vision population could be appropriately met in a secondary level.3

    Human Resources

    Assessment at this level includes ophthalmologists and optometrists; refractionists, orthoptists, technicians, and nurses.2

    Personnel will require additional training in assessment of visual function, calculation of magnification needs, prescription of low-vision devices, and counselling skills to provide guidance on education, vocation, and environment.

    Purposes

    Personnel should have good communication skills and be able to do the following:1,2

    • Test distance and near VA
    • Perform objective and subjective refraction
    • Perform minimum essential low-vision assessments
    • Prescribe essential low to medium magnification devices for near and distance, with training in the use of these devices
    • Advise patients on optical interventions and environmental modifications
    • Refer people to the most appropriate person or organization for further training, financial help, and education
    • Refer young children and those with complex needs to the tertiary level
    • Ensure regular follow-up of children who were seen at the tertiary level

    Management of ocular injuries, corneal ulcers, and other more severe diseases and the provision of spectacles take place at the secondary level.

    Tertiary Level

    At the tertiary level a team of trained professionals provide care that involves assessment of visual function, refraction, prescription, and use of full-range optical, optical and electronic devices, multidisciplinary rehabilitation, and training in visual skills and mobility, including orientation and mobility training. Approximately 20% of patients with low-vision needs will be met by the tertiary level care.3

    Purposes

    Well-trained, dedicated, low-vision staff can provide the following:1,2

    • Complex assessment tests
    • Refraction of people with complex problems
    • Provision of a wide range of devices, including electronic devices
    • Good links to education and rehabilitation services
    • Training in the use of low-vision devices

    Prevention and treatment of retinopathy of prematurity, surgical treatment of eye conditions, and provision of optical devices all take place at the tertiary level.

    References

    1. World Health Organization - Programme for the Prevention of Blindness - Management of low vision in children - Report of a WHO Consultation. Bangkok: 1992. WHO/PBL/93.37.
    2. van Dijk K. Low vision care: who can help? Community Eye Health. 2012;25(77):14‑15.
    3. Ryan Models of low vision care: past, present and future. Clin Exp Optom. 2014;97:209‑213.
    4. American Academy of Ophthalmology. Preferred Practice Patterns: Vision Rehabilitation.
    5. AAPOS Vision Screening Recommendations. American Association for Pediatric Ophthalmology and Strabismus.
    6. Minto H, Awan H. Establishing Low Vision Services at Secondary Level. Community Eye Health. 2004;17(49):5.