Microphthalmia/Anophthalmia is a condition characterized by faulty development of the eye, leading either to small eyes or the total absence of one or both of the eyes. In most cases, microphthalmia/anophthalmia is seen as part of a syndrome, in association with several other developmental defects. Isolated microphthalmia is a rare occurrence. The condition can range in severity from only slightly smaller than normal eyes, resulting in almost normal vision, to a complete absence of both eyes. Those affected with the milder form may develop long-sightedness, nystagmus, or strabismus. The etiology of the disease condition remains unclear. However, researchers have suggested that gestational acquired infections, maternal vitamin A deficiency and/or chemical or radiation exposure could be contributing factors.
The condition can be diagnosed both pre- and post-natally via ultrasound, CT, or MRI scanning. Other ocular conditions, such as cryptophthalmos, cyclopia, and congenital cystic eye, need to be considered for differential diagnoses. Management depends upon the severity of the condition. Mild to moderate microphthalmia can be managed conservatively. If only one eye is affected, patching of the better eye can encourage enhanced vision in the affected eye. More severe forms and anophthalmia require more extensive intervention in the form of implants, expanders, grafts, and soft tissue reconstruction.
Kohn et al. (1988) described a large consanguineous Arab kindred in Palestine in which 19 persons over 3 generations had bilateral profound microphthalmia without associated anomalies and with normal intelligence. One female infant had tracheoesophageal fistula repaired in the neonatal period; when examined at 1 month of age, she had mild right hydronephrosis by intravenous pyelography and ultrasound. Kohn et al. (1988) stated that these abnormalities were 'undoubtedly unrelated to the microphthalmia'.
Bar-Yosef et al. (2004) studied 4 families (2 of Arab origin, 1 of Bedouin origin, and 1 of Persian Jewish origin) with autosomal recessive isolated microphthalmia/clinical anophthalmia and no associated eye anomalies. In the 2 Arab families, 1 of which had previously been reported by Kohn et al. (1988), they identified homozygosity for a missense mutation (1237G-A; R227W) and an approximately 4-kb deletion encompassing exon 3 of the CHX10 gene, respectively. No mutations were identified in the other 2 families.
In six affected individuals from two consanguineous families from Qatar with non-functional eyes (bilaterally) with very small globes and cloudy corneas, Faiyaz-Ul-Haque et al. (2007) identified homozygosity for an R200P mutation in the CHX10 gene. Craniofacial features, height, weight, and intelligence were normal in these patients. Unaffected parents were heterozygous for the mutation.