Pediatric low vision refers to irreversible permanent visual impairment or loss of vision in people aged below 21, which medical treatment, refractive error correction, or surgery cannot help. Unlike adults, children with low vision experience worrisome challenges to reach their milestones in development. They are disadvantaged in education, social interactions, and independence. Pediatric low vision is often misdiagnosed as a systemic health issue or intellectual disability.
According to the World Health Organization (WHO), pediatric low vision describes visual acuity of less than 6/18 to light perception or a visual field less than 10 degrees from the fixation point. A child with low vision can also suffer from both decreased vision and decreased field of vision. These children are not blind since they retain a little useful vision.
Children with low vision lack central, peripheral, and clear vision alongside a lack of contrast sensitivity, depth perception, and ability to process visual images. They cannot perform many daily activities like playing with others, writing at the same speed as others, reading from the board, and recognizing people in the streets.
Causes & Risk Factors
The causes of pediatric low vision are many and varied, such as eye’s structural abnormalities, a systemic or genetic disease, or cortical visual impairment (CVI). Structural abnormalities include corneal opacification, primary aphakia, congenital cataract, optic nerve hypoplasia, chorioretinal coloboma, and foveal hypoplasia. Eye conditions can also contribute to low vision, such as congenital nystagmus, ocular trauma, retinal dystrophy, limbal stem cell deficiency, iatrogenic damage, and aniridia. Systemic and genetic diseases contributing to pediatric low vision include Leber congenital amaurosis, retinitis pigmentosa, Stargardt disease, ocular albinism, and achromatopsia. Other syndromes include Berdet Beidl, Axenfeld-Rieger, Sturge Weber, CHARGE, Lowe, Hurler, Usher, and Stickler syndrome.
Signs & Symptoms
Signs and symptoms of low vision include:
- Difficulty in recognizing familiar faces
- Difficulty in recognizing potential hazards such as a wall
- Reading difficulties. Printed matter appears distorted or broken
- Unlike adults, children have impaired mental health which manifests in symptoms such as mood swings, changes in cognition, nightmares, and headaches
The signs and symptoms are best understood by looking at age and expected milestones. These include:
- Birth to four months – An average child should focus and track familiar objects. Signs of visual impairment include delays in smiling, absent or delayed blink reflex, and reduced sensitivity to bright light
- Five to eight months – There is the normal development of color vision, depth perception, and recognizing faces. Signs of low vision include unable to recognize familiar faces, delayed or no eye contact, and inability to fixate on an object
- Nine to 24 months – The child can crawl, grasp objects, and do hand and eye coordination. Abnormalities include undirected hand and/or arm movements and lack of awareness of their own hands
- More than 24 months – Children at this age should be crawling, walking, and exploring the environment. Signs of visual impairment manifest where the child crawls awkwardly, has problems reaching toys, trips frequently, has problems climbing steps or navigating curbs, and holds objects close to the face
- School-going age – By this age, a normal child should have no problem reading. Signs of low vision may include a headache and difficulties with reading
Diagnosis varies, and the order and components of the examination depend on the child's age and ability to participate. If there is suspicion of low vision, children are referred to an ophthalmologist as early as possible for visual assessment. Usually, ophthalmology assessment is ideal when children attain school-going age or once they are old enough to describe symptoms such as blurry vision. However, some parents seek medical attention immediately they notice abnormalities with visual behavior. The following can help diagnose the condition:
- History – The ophthalmologist seeks information about when the symptoms began, their progress, and severity. If the child can describe their symptoms, their participation is encouraged to build self-confidence. The ophthalmologist obtains the family's visual impairment history, the extent of the impairment, the impact of the visual symptoms on the child's psychosocial functioning and well-being, refractive errors and whether the child has used glasses and low vision aids, and near tasks or mobility difficulties
- Refractive error tests such as the cycloplegic refraction test
- Contrast sensitivity – Hiding Heidi contrast face test can help
- Color vision test – Using validated color tests such as the Ishihara test
- Visual field test – Goldman test is useful in cooperative children about six years old and above
- Visual acuity test – Use of charts to determine a child’s visual acuity which is measured with school performance, cognitive ability, and age in mind. Teller acuity cards are used for children aged 0-36 months, LEA symbols for those aged four to seven years, while the LogMAR chart is best for children aged eight to 13 years
- Other tests such as electroretinogram, ocular coherence tomography, and visually evoked potential
Treatment is aimed at rehabilitation rather than cure. The aim is to find ways to help a child maximize the little vision that remains. It's about assisting children in functioning in education and play. The child is seen by a team of interdisciplinary professionals who provide the components of low vision care. Diverse groups are involved, such as schools, community programs, and eye specialists, to give the child comprehensive care. Management depends on the child’s low vision level and age. Acute ocular problems are treated. Surgery is performed if there is a need, such as cataracts surgery. For refractive errors, contact lenses and eyeglasses can help.
Low Vision Devices
The standard gold treatment for low vision is the use of low vision devices. Early intervention is necessary, especially for children aged below three years, where special education professionals work together with family members to develop a suitable program. The program should involve a teacher and sometimes speech, occupational, and physical therapist. Low vision devices include telescopes, hand-held magnifiers, single-vision spectacle magnifiers, tinted lenses, and binoculars. Non-optical devices such as a closed-circuit TV (video magnifiers) and books with large prints can help. Others include smartphone applications and assistive technology such as voice recognition, audio books, email screen readers, audio conversion for text messages, etc.
Prognosis & Long-Term Outlook
The prognosis depends on the severity and early intervention. Some children have mental health concerns compared to better-seeing children. This is because of a high dependency rate on parents and caregivers for day-to-day activities. If detected early, a child can lead a quality life with more robust academic performance.
Prevention & Follow Up
Because a child’s visual needs can change rapidly, regular follow-up is recommended.