216 CHAPTER 15 Ocular manifestations of systemic disorders
Congenital rubella
DEFINITION/OVERVIEW AND ETIOLOGY
Since the introduction of the vaccine, rubella is rare in the US. It does, however, remain a major cause of blindness in developing countries. Transplacental infection occurs during the viremic phase in the mother. The incidence of congenital infection is dependent on the month of gestation of the viremia.91 The diagnosis is confirmed by the presence of IgM antibodies in the cord blood. Table 17 presents the incidence and rate of infection with gestational age.
Systemic manifestations include:
•Hearing loss.
•Intrauterine growth retardation.
•Heart disease.
•Microcephaly.
•Mental retardation.
•Hepatitis/hepatomegaly.
CLINICAL PRESENTATION OF OPHTHALMOLOGIC MANIFESTATIONS
Microcornea or microphthalmia occurs in 10% of affected individuals. Bilateral cataract formation is the most visually significant complication and, if left untreated, leads to amblyopia. A ‘salt and pepper’ retinopathy is the classic retinal finding; its effect on vision is variable. Glaucoma is present in less than 10% of cases. The mechanism of glaucoma is multiple, including malformation of the aqueous outflow, chronic uveitis, or postcataract surgery. Keratoconus, chronic uveitis, iris coloboma, persistant pupillary membrane, and anisocoria have all been reported. Nystagmus may develop secondary to the amblyopia from the presence of a cataract. Strabismus commonly occurs after cataract surgery.
MANAGEMENT/TREATMENT
Prevention, with the use of the RA-27 vaccine, is the mainstay. If cataracts are present, early lensectomies and visual rehabilitation with aphakic spectacles or contact lenses is appropriate. With early surgery, even in the presence of nystagmus and retinopathy, visual outcome can be as good as 20/60.
Table 17 Incidence and rate of congenital rubella infection with gestational age
Gestational age |
Risk of developing |
Risk of developing a congenital defect |
at time of viremia |
congenital infection (%) |
if an infection occurs (%) |
1–11 weeks |
90 |
100 |
11–20 weeks |
50 |
30 |
20–35 weeks |
37 |
None |
35+ weeks |
100 |
None |
|
|
|
CHAPTER 16
217
Oculoneurocutaneous syndromes (‘phakomatoses’)
Jerry A. Shields, MD and Carol L. Shields, MD
•Introduction
Genetics Malignant potential Formes frustes
•Tuberous sclerosis complex (Bourneville’s syndrome)
•Neurofibromatosis (von Recklinghausen’s syndrome)
•Retinocerebellar hemangioblastomatosis (von Hippel–Lindau syndrome)
•Racemose hemangiomatosis (Wyburn-Mason syndrome)
•Encephalofacial cavernous hemangiomatosis (Sturge–Weber syndrome)
•Oculoneurocutaneous cavernous hemangiomatosis
•Organoid nevus syndrome