Antenatal diagnosis of anophthalmia by three-dimensional ultrasound: a novel application of the reverse face view

Authors


Abstract

The prenatal diagnosis of anophthalmia can be made on the demonstration of absent eye globe and lens on the affected side(s) on two-dimensional ultrasound examination, but when the fetal head position is unfavorable three-dimensional (3D) ultrasound may reveal additional diagnostic sonographic features, including sunken eyelids and small or hypoplastic orbit on the affected side(s). We present two cases of isolated anophthalmia diagnosed on prenatal ultrasound examination in which 3D ultrasound provided additional diagnostic information. The reverse face view provides valuable information about the orbits and the eyeballs for prenatal diagnosis and assessment of anophthalmia. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.

Case Reports

Case 1

A 25-year-old woman, gravida 2 para 1, was referred because of unusually echogenic orbital contents bilaterally with no discrete globe or lens detectable on fetal morphology ultrasound scan at 20 weeks' gestation. She had one normal child and no family history of congenital abnormalities. On two-dimensional (2D) ultrasound examination using an iU22 ultrasound machine (Philips, Bothell, WA, USA), the fetal globes and the lenses could not be identified and the orbits appeared small (Figure 1a). These findings were confirmed on three-dimensional (3D) ultrasound using a 6–2-MHz curved 3D transducer, which showed the ‘sunken eyelid’ appearance and hypoplastic orbits (Figure 1b). No other structural abnormalities were detected. Amniocentesis was performed and karyotyping revealed a normal fetal karyotype. Isolated bilateral anophthalmia was diagnosed. The couple opted for termination of pregnancy, and the diagnosis was confirmed on postmortem examination.

Figure 1.

(a) Two-dimensional ultrasound image at 20 weeks' gestation in a case of bilateral anophthalmia (Case 1), showing that the orbits were small and the globes and the lenses were not demonstrable. (b) Three-dimensional ultrasound image at 20 weeks' gestation showing that the orbits appeared small in the skull.

Case 2

A 25-year-old woman, gravida 4 para 0, was referred because of a history of recurrent miscarriages. Serial ultrasound scans were performed every 4 weeks to assess fetal growth. The fetal face could not be clearly visualized owing to the fetal head position on morphology scan at 20 weeks' gestation, and the fetal head position remained unfavorable for examination of the fetal face throughout the pregnancy. The right globe was seen to be absent on 2D ultrasound examination. On 3D ultrasonography, performed at 31 and 38 weeks' gestation, there was asymmetry of the fetal face and the right eyelids were sunken (Figure 2a). The globe and the lens could be identified in the left eye (Figure 2b and 2c) but not in the right (Figure 2c). The lack of the right globe (Figure 2c) and a rudimentary orbit (Figure 2d) could be easily identified on the reverse face view. Moreover, the right orbit was seen to diminish in size progressively in utero (Figure 3). The diagnosis of right anophthalmia was confirmed after birth.

Figure 2.

Three-dimensional ultrasound images at 38 weeks' gestation in a case of unilateral anophthalmia (Case 2). The fetal face appeared asymmetrical with sunken right eyelids (a). The globe and the lens could be seen within the left orbit (b, arrow) but were not demonstrable on the right side (c). On reverse face view, absent globe and lens (c) and a rudimentary orbit (d) were demonstrable on the right side. The arrow in (c) indicates the left-eye lens.

Figure 3.

Three-dimensional reverse face view ultrasound images at 31 weeks' gestation in a case of unilateral anophthalmia (Case 2), showing the presence of the right orbit (a), which was smaller than the left one but was proportionately more similar in size than it was 7 weeks later (cf. Figure 2d). (b) The contents of the left orbit including the lens (arrow) could be identified but the contents of the right orbit could not (cf. Figure 2c).

Discussion

Congenital anophthalmia is a rare condition with a prevalence of 0.6 per 10 000 births1. About 10% of cases appear isolated and the rest are associated with other anomalies. True or primary anophthalmia is incompatible with life because, in such cases, the primary optic vesicle stops developing within the first few weeks after conception and the abnormal development involves major defects in the brain2. The term ‘anophthalmia’ has been used as a synonym for ‘extreme microphthalmia’ or ‘clinical anophthalmia’3. In all cases of congenital anophthalmia, the soft tissue hypoplasia and restricted development of bony orbital structures begin in utero, but in most cases an ocular remnant can be detected in the orbit4. These changes appear to have been progressive in utero in our Case 2 (Compare Figures 2d and 3). Postnatally, a suitable prosthesis has to be put in place as soon as possible to avoid cosmetically devastating midface asymmetry and to reduce the social and psychological implications for the parents and the patient. Prenatal diagnosis may allow psychological preparation and planning of management.

The use of 2D5, 6 and 3D7 ultrasonography in the antenatal diagnosis of unilateral anophthalmia, in which the diagnosis was based on the non-visualization of the eyeball and lens, has been described previously. In one of these reports, 3D ultrasound was noted to be superior to 2D when the fetal head position was unfavorable for the demonstration of the fetal face on 2D ultrasound7, as in our Case 2.

The use of 3D ultrasound in the prenatal diagnosis of fetal facial abnormalities is well known7. The application of the reverse face view was first described for facial cleft8, but proved to be invaluable in providing a quick and easy diagnosis of anophthalmia in our Case 2, when imaging with 2D ultrasound was unsatisfactory owing to the fetal head position. Since the reverse face view is relatively free of the problem of shadowing8, a satisfactory 3D volume taken at the time of acquisition, with adequate inclusion of both orbits (Figure 2a), will enable effective examination of the orbits (Figure 2c) and eyeballs (Figure 2d). It may also provide information on the size of the affected orbit and remnant of its contents for postnatal management. Anophthalmia may be associated with other fetal structural3, 5, 9, syndromal1, genetic3 or chromosomal1 abnormalities, and 3D ultrasound may further aid in the identification of these abnormalities.

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