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CONGENITAL ABNORMALITIES OF THE EYE- ANIRIDIA (Medical Mangement…
CONGENITAL ABNORMALITIES OF THE EYE- ANIRIDIA
Definition
It is the absence of the iris, usually involving both eyes. It is a congenital, hereditary, bilateral, extreme form of iris hypoplasia that may be associated with other ocular defects
Medical Mangement
Prophylaxis in patients with aniridia is directed toward the prevention of glaucoma, which includes treatment with
miotics
Limbal stem cell deficiency associated with aniridia can be treated with
Lubricating drops
Topical steroid pulses
Vitamin A ointments
Autologous serum drops
The medical treatment of aniridia is directed toward control of intraocular pressure,
Miotics
Beta-blockers
Sympathomimetics
Carbonic anhydrase inhibitors
Prostaglandin analogues
Pathophysiology
The pathogenesis of aniridia is attributed to a primary developmental arrest of the neuroectoderm and a secondary alteration of all 3 neural crest waves of the mesenchyme. The functional development of the anterior segment is a complex interrelationship between the neural ectoderm and the neural crest waves of the mesenchyme
Signs and Symptoms
Absence of iris
Nystagmus
Strabismus
Reduced vision
Causes
An identifiable chromosome deletion of the short arm of chromosome 11, including band p13.
Patients with aniridia who have a positive family history: Two genetic loci for aniridia have been identified, one (AN1) on chromosome arm 2p and one (AN2) on chromosome 11.
As an isolated ocular malformation, aniridia is an autosomal dominant disorder, which is caused by a mutation in the PAX6 (paired box gene family) gene.
Diagnostic Studies
Laboratory Studies
Histologic Findings
Surgical Management
Management of corneal opacification
Limbal stem cell transplantation
Keratoplasty
Keratoprosthesis
Management of cataract in patients with aniridia
In-the-bag lens implantation in cases without lens dislocation
Use of opaque intracapsular rings to produce an artificial pupil or use of a large intraocular lens with a clear central optic and an opaque periphery
In-the-bag IOL placement with intracapsular rings, when there is slight lens displacement
Management of glaucoma in patients with aniridia
Goniotomy: This includes prophylactic and early surgical therapy. In early surgical therapy, some risk to the crystalline lens and the zonules exists because the surgery is performed from the anterior approach.
Trabeculotomy is safer than goniotomy. The tissues can be defined more clearly, and accurate surgery can be performed. However, failures are common.
Health Education
Thoroughly educating the patient and parents about aniridia and the associated ocular anomalies and systemic problems is mandatory.
Nursing Care Plan
Nursing Management
Risk Factors
