Pediatric Vision Screening
Pediatric vision screening is intended to identify children with vision disorders including amblyopia (poor vision in an otherwise normal eye), strabismus (misalignment of the eyes), significant refractive error (need for glasses) or other eye abnormalities. Vision screening can be performed in the community setting such as at health fairs, in preschools, grade schools, or can be performed in the medical home (pediatrician or family doctor’s office).
Amblyopia can be caused by significant refractive error, misalignment of the eyes or deprivation (anything that blocks a clear image from reaching the retina) such as visually significant ptosis (droopy eyelid) or a cataract. Amblyopia is reversible with treatment in childhood, and it is generally believed that the earlier amblyopia risk factors are identified, and amblyopia treatment is initiated the more likely the child will develop normal vision. Left untreated amblyopia can lead to a permanent reduction in vision in one or both eyes and is the leading cause of vision loss in adults under the age of 40.
There are a variety of forms of pediatric vision screening methods that programs can choose from depending on the age of the children they plan to screen, the environment they are screening in and amount of money they have to invest. One of the keys to a successful pediatric vision screening program is to ensure that children who are identified as having potential amblyopia risk factors receive a complete pediatric ophthalmology examination including a dilated fundus examination, a dilated (cycloplegic) refraction and fundus examination by a pediatric ophthalmologist.
The American Association for Pediatric Ophthalmology and Strabismus have devised standards for comparing pediatric vision screening methods. These guidelines are set against a child’s cycloplegic pediatric ophthalmology examination in order to determine if the child’s vision screening should have prompted a referral to a pediatric ophthalmologist or if they should have passed the screening.
Types of Pediatric vision Screening
Subjective screening requires significant participation from a child to identify optotypes such as letters and shapes. It is most effective in verbal children age 5 and older, but may be attempted in younger verbal children. Subjective screening includes various forms of visual acuity testing.
Pediatric vision screening with acuity measurements is the most widely used method. This method is inexpensive, but can be difficult to execute properly. The testing distance can vary from 3 – 20 feet and it is critical that the child be tested at the appropriate distance for the chart. It is also important that an appropriate eye chart be selected. Optotypes that can be considered are: Sloan, HOTV, Lea symbols and Patti Pics. The optotypes should be presented in a line or singly with crowding bars, as isolated optotypes may over-estimate vision. The child should be seated comfortably in a chair or on their parents lap and encouraged not to lean forward. The testing distance needs to be measured from the child’s face to the eye chart, and if sitting on a parents lap this may alter the testing distance. A hand should never be used to cover one eye. The best method is to use a stick on eye patch, which can be purchased or can be fashioned out of fabric tape and a tissue. It is important that the examiner pay close attention that the child is not peaking from the side of the patch or holding their head sideways. Another alternative is pediatric occlusion glasses, which have black plastic over one eye and large foam animal shapes around the edges making peaking nearly impossible.
Computerized visual acuity testers are also available including: Vision Quest 20/20, Innova and M&S. These devices automate the testing protocol and are performed utilizing a computer monitor. Vision Quest is fully automated and uses crowded HOTV letters in a matching game disguised as a video game.
Objective screening requires less input from children and is faster. With objective screening, the child merely need to focus on a device long enough to obtain a measurement.
There are a number of autorefractors which can be used to evaluate for amblyopia risk factors. Most of these tests are done monocularly and therefore do not screen for strabismus. These devices are used on undilated eyes and will give the user an estimation of the child’s refractive error. Based on pre-determined referral criteria, the device or examiner can quickly determine if the child passed the screening or should be referred for further evaluation by a pediatric ophthalmology for a cycloplegic refraction and comprehensive examination. The advantage to autorefractive screening is that it can be performed not only on verbal children, but on pre-verbal and non-verbal children as well. It is also much faster than acuity screening
Current available autorefractors used for pediatric vision screening include: Grand Seiko binocular autorefractor, Retinomax and the SureSight. While the SureSight is specifically marketed as a vision screening device, both the Retinomax and SureSight auto refractors were validated in the Vision in Preschoolers Study (VIPS).
Photoscreeners take images of the corneal light reflex from a child’s pupil. The test is performed binocularly and is based on the reflexes an examiner or a computer program can analyze to determine if there is strabismus and/or significant refractive error. Photoscreeners can also detect other anatomical abnormalities, including cataract, coloboma or ptosis. The test is fast and can be performed on both verbal and pre-verbal children. This method is also much faster than acuity screening, but unlike autorefrefractive screening, it can directly screen for manifest strabismus.
Current available photoscreeners include: iScreen, MTI, plusoptiX, Spot, and Visiscreen. The MTI photoscreener, iScreen and Visiscreen use a visible light flash while plusoptiX and Spot utilize infrared light which is not visible to the child.
Visual Evoked Potential/Response (VEP/VER)
There is currently one device available from Diopsys which estimates visual acuity, or the difference in visual acuity between two eyes utilizing a sweep VEP. The machine analyze the results and give the user a pass/refer result.
- Performance Data of Commerically Available Instruments for Pediatric Photoscreening and Autorefraction.
- American Association for Pediatric Ophthalmology and Strabismus
- Childrens Eye Foundation
- See by Three
- American Academy of Pediatrics Section on Ophthalmology
- Alaska Blind Child Discovery
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