Refractive criteria based on the literature
| Refractive error | Normal refraction | Borderline refractive error | Abnormal refractive error |
|---|---|---|---|
| Clinically cylinder errors are recorded in minus cylinder form, hence the cylinder criteria are in minus values. A child’s refraction was categorised on the basis of the eye with the greatest error—for example, right +3.50/−1.00, left +3.50/−1.50 would be categorised as an abnormal refractive error on the basis of the left eye. | |||
| Hypermetropia | <+3.00 DS | +3.00 to < +4.00 DS | ⩾+4.00 |
| Myopia | <−1.00 DS | −1.00 to −2.00 DS | >−2.00 DS |
| Astigmatism | <−1.00 DC | −1.00 to <1.50 DC | ⩾−1.50 DC |
| Anisometropia | <1.00 DS/DC | <1.00 DS/DC | ⩾1.00 DS/DC |