[Possibilities and limitations of amblyopia screening with auto-refractometers]

Amblyopia is a frequent vision disorder with a prevalence of 3-6%, for which early treatment is more effective. More than half of the cases of amblyopia are due to refractive errors so that they are not obvious due to strabismus or other ocular abnormalities; therefore, examinations for early recognition are essential. Because no nationwide ophthalmological examination of infants with cycloplegia has been established in Germany, screening for refractive errors in the first 3 years of life could be very helpful. Only children with a very high risk of ametropia should be referred for a full ophthalmological and orthoptic assessment of cycloplegia in order to prevent excess prescription of eyeglasses. Mild amblyopia with a borderline refraction error can be more reliably detected with visual acuity tests at a later age of 3-4 years and still be treated successfully before entering school. Even with a good sensitivity and specificity of approximately 90%, refraction screening with handheld binocular video refractometers has a positive predictive value of 30%, which should be considered acceptable; however, screening with refractometers alone is insufficient to detect all types of amblyopia. Cataracts can easily be detected in >95% of patients but microstrabismus <6° cannot be detected with sufficient reliability. If other risk factors, such as a negative Lang stereopsis test, ptosis, other ocular abnormalities, developmental delay or a positive family history are present, a full ophthalmological evaluation with cycloplegic refraction is necessary.