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| microphthalmos [2026/07/27 12:01] – [Associated Conditions] Scott Larson | microphthalmos [2026/07/27 12:06] (current) – [Definition] Scott Larson |
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| ===== Definition ===== | ===== Definition ===== |
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| **Microphthalmos** (also spelled microphthalmia) is a congenital eye malformation characterized by a **reduction in the volume of the eye**, typically defined as a corneal diameter less than 10 mm or an anteroposterior globe diameter less than 20 mm (or an axial length below 2 standard deviations for chronological age).[1][2] One or both eyes may be affected. In severe cases the eyeball may appear absent, though residual eye tissue is generally present; this severe form should be distinguished from true anophthalmia, in which no eyeball forms at all.[3] Microphthalmos exists on a phenotypic continuum with anophthalmia and coloboma, collectively referred to as the **MAC spectrum** (microphthalmia/anophthalmia/coloboma).[4][2] | **Microphthalmos** (or microphthalmia) is a congenital eye malformation characterized by a **reduction in the volume of the eye** |
| | * Corneal diameter typically < 10 mm |
| The combined birth prevalence of anophthalmia and microphthalmia is estimated at **up to 30 per 100,000 population**, with microphthalmia reported in up to 11% of blind children.[5] Microphthalmia may or may not result in significant vision loss, and it can occur in isolation (nonsyndromic) or as part of a broader syndrome (syndromic) in approximately one-third to one-half of cases.[3][5] | * Anteroposterior globe diameter less than 20 mm (or an axial length below 2 standard deviations for chronological age).[1][2] |
| | * One or both eyes may be affected. |
| | * Severe cases the eyeball may appear absent, though residual eye tissue is generally present; this severe form should be distinguished from true anophthalmia, in which no eyeball forms at all.[3] |
| | * Microphthalmos exists on a phenotypic continuum with anophthalmia and coloboma, collectively referred to as the **MAC spectrum** (microphthalmia/anophthalmia/coloboma).[4][2] |
| | * Combined birth prevalence of anophthalmia and microphthalmia is estimated at **up to 30 per 100,000 population**, |
| | * Microphthalmia reported in up to 11% of blind children.[5] |
| | * Isolated (nonsyndromic) 66% |
| | * Part of a broader syndrome (syndromic) 33%.[3][5] |
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| ===== Associated Conditions ===== | ===== Associated Conditions ===== |