Korean J Ophthalmol.  2010 Oct;24(5):314-317. 10.3341/kjo.2010.24.5.314.

Two Cases of Mirror-Image Eye Anomalies in Monozygotic Twins

• Kim WK
• Chung SA
• Lee JB

• KMID: 974328
• DOI: http://doi.org/10.3341/kjo.2010.24.5.314

Abstract

We report two cases of mirror image anomalies in two different pairs of monozygotic twins. In case 1, the twins exhibited mirroring of strabismus and refractive errors. Twin 1 had 35 prism diopters (PD) right intermittent exotropia at distant fixation and myopic anisometropia that was spherical 2.00 diopters more myopic in the right eye. Twin 2 had 35 PD left intermittent exotropia at distant fixation and her left eye was more myopic by - spherical 1.00 diopters. In case 2, the twins were diagnosed with infantile nystagmus with upbeat jerk. Twin 1 exhibited a habitual head turn of 30degrees to the left with dampening of her nystagmus in dextroversion. Twin 2 also exhibited abnormal head position, but in his case the habitual turn was 30degrees to the right. We believe that this is the first report describing mirror imaged intermittent exotropia with anisometropia and infantile nystagmus with opposite abnormal head positions in pairs of monozygotic twins.

Keyword

Anisometropia; Identical twins; Infantile nystagmus; Intermittent exotropia; Mirror image anomaly

MeSH Terms

Child
Eye Abnormalities/*diagnosis/genetics/surgery
Eyeglasses
Female
Humans
Male
Twins, Monozygotic
Visual Acuity

Figure

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  Fig. 1 Postoperative image of 8-year-old identical twins who underwent 8.5 mm bilateral lateral rectus recessions at 1 month of ago. Before surgery, Twin 1 had 35 prism diopters (PD) right intermittent exotropia, while twin 2 had 35 PD left intermittent exotropia at distant fixation.

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  Fig. 2 These identical twins exhibited the up beat jerk type of infantile nystagmus. Twin 1 (right) had a habitual head turn of 30° to the left with dampening of nystagmus in dextroversion, while twin 2 (left), had a habitual head turn of 30° to the right.

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  Fig. 3 Vertical electronystagmography of identical twins with infantile nystagmus shows that twin 1 had upbeat jerk type nystamus (B) with dampening of nystagmus in dextroversion (D), and that twin 2 also had up beat jerk type nysgagmus (A) with dampening in levoversion (C). This result is consistent with the preferred abnormal head positions of these identical twins.

Reference

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