| 1. | Up to the age of three months, many children such as seen in SLIDE 1 may demonstrate transient esotropia or exotropia. However by three months of age their eyes should be properly aligned and they should be able to fix and follow with each eye separately. |
| 2. | Demonstrates pseudoesotropia related to epicanthal folds. These are present because of the lack of development of the bridge of the nose which does not occur until age four and at which time the epicanthal folds are dragged out of the corners of the eyes to produce a more adult appearance. |
| 3. | Shows how little sclera is normally visible nasally in small children as it is covered by the epicanthal fold. |
| 4. | The appearance of esotropia, as seen in SLIDE 4 is most noticeable inside gaze when the eye slips under the epicanthal fold simulating the appearance of esotropia. |
| 5. | Children with true congenital esotropia as seen in SLIDE 5 may also have epicanthal folds, but in this case a large angle of esodeviation is apparent. |
| 6-8. | Epicanthal folds may be quite impressive (as seen in 6-8) and cause the appearance of a pseudoesotorpia in gaze to either side. Because of the sloping walls of the orbit the eye actually is aimed a little bit temporal of perpendicular in the orbit. This leads to a discrepancy between the visual axis and the pupillary axis and exaggerations of this angle kappa may simulate various types of strabismus. Normally the corneal light reflex is centred slightly nasal of centre (positive angle kappa). |
| 9. | Shows a large negative angle kappa of the right eye with the light reflex decentred temporally, simulating an esotropia. |
| 10. | However covering the left eye SLIDE 10 indicates no movement of the eye and therefore no strabismus. |
| 11. | Shows a large positive angle kappa of the left eye, in this case caused by mild retinopathy of prematurity and temporal drag of the macula. |
| 12. | Covering the right eye reveals no movement of the left eye indicating that the eye is lined up with the macula and strabismus is not present. |
| 13. | Shows marked facial asymmetry with the left orbit being higher than the right, simulating a vertical deviation (hypertropia). |
| 14. | demonstrates this orbital asymmetry, and a cover test of either eye will demonstrate no deviation of the either eye. |
| 15-16. | Children whose eyes are set close together (15) often look esotropic, while children whose orbits and eyes are set further apart (16) may look exotropic. Both these children have straight eyes. |