Congenital Anophthalmia Classification



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Congenital Anophthalmia
Classification

  1. Syndromic

  2. Non-syndromic


Evisceration is the removal of the contents of the globe while leaving the sclera and extraocular muscles intact.

Enucleation is the removal of the eye from the orbit while preserving all other orbital structures.

Exenteration is the most radical of the three procedures and involves removal of the eye, adnexa, and part of the bony orbit.
Incidence

    • M=F

    • 1 in 50,000 births

    • True anophthalmos

      1. complete absence of the globe through failure of formation of the optic vesicle, and it is an extremely rare condition.

    • Micropthalmos

      1. Unilateral in 75%

      2. presents most often as an isolated finding or within the spectrum of otomandibular dysostosis.


Embryology

  • developmental-field defect located in Pfeifer’s diacephalic region

  • defined as the (bilateral) border zone between the frontonasal and the posterolateral regions of the face and stretches from the temple, crossing the orbit and the lateral parts of the nose, including the ala nasi, running along the philtral column of the upper lip, and ending between the premaxilla and the posterolateral part of the palate and the upper jaw at the nasopalatine duct



  • types of craniofacial malformations that occur here include isolated clefts of the lip (alveolus and palate) or of the nose, most of the Tessier-type clefts (numbers 2, 3, 4, 8, 9, 10, 11, and 12), as well as cryptophthalmia, microphthalmia, and anophthalmia.

  • Thus, microphthalmia and anophthalmia also may be found in conjunction with hypertelorism (a malformation of the frontonasal region) or with hemifacial microsomia (a disorder of the posterolateral region).

  • At the time of birth normal globes are said to have a volume of 2.5 ml.

  • eye and the orbit grow the fastest during the first year of life.

  • 70% of the increase of the globe’s volume occurs by 4 years of age and 90 percent by age 7.

  • While growth of the eye ends at age 14, the growth of the orbit ends at age 11 in females and at age 15 in males

  • This is why enlarging the orbit in the first years of life should be attempted

  • It is known that the developing eye, being part of the “functional matrix,” has a marked effect on orbital growth.



Considerations

  • globe plays a role of essential importance in orbital growth, and its diminished contribution in the congenitally anophthalmic orbit causes:

  1. microorbitism

  2. conjunctival sac atresia

  3. short, phimotic lids (microblepharism)

  • In severe microphthalmos, the eye is grossly hypoplastic and blind.

  • Unilateral clinical anophthalmia always results in hypoplasia of the ipsilateral bony orbit, as there is no stimulus inducing growth of the orbital socket.

  • This, in turn, leads to facial asymmetry with hypoplasia of the ipsilateral midface, a canted occlusal plane, and a short ascending ramus of the mandible.

  • In contrast, bilateral anophthalmia may lead to symmetrical microsomia of the midface as a whole


Management

  • Formerly, microphthalmia and anophthalmia were treated by osteotomy of the bony orbit followed by lengthening of the lashbearing lid and grafting of mucosa to the socket




  • Early management consists of eviscerated (removal of its contents, preserving the sclera with its extraocular muscle attachments and Tenon’s capsule) or enucleated (removal of the globe, preserving Tenon’s capsule) and replaced by a spherical implant




  • Asscess is usually through combined bicoronal and lid incisions

Methods


    1. Serial expansion with fixed sized expanders

      • implant serves as a support for the eyelids and conjunctival sac anteriorly and maintains the volume of the orbit. Exchanged every 6 months for larger prostheses

      • In a second stage, a removable ocular prosthesis that mimics the eye is fitted to the contours of the conjunctival sac

    2. dermis fat grafts

      • idea was that this would grow and exert some pressure onto the bony walls of the orbit.

    3. expansion osteotomy

      • three wall orbital expansion (Tessier)

      • lateral wall osteotomy and temporalis transfer for bulk and vascularised bed to support SSG (Lee PRS 1999)



    1. osteotomy and tissue expander

      • several shortcomings: decrease of interorbital distance and a high percentage of extrusions of these expanders.

    2. hydrophilic (self-inflating) expanders

      • copolymer of methylmethacrylate andN-vinylpyrrolidon

      • PRS Oct 2005 – reported that palpebral fissure lengthened, the conjunctival sac expanded and the bony orbit stimulated to grow by these expanders



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