Cataract
Brian J. Forbes, MD, PhDGil Binenbaum, MD
Cataract - BASICS
Cataract - description
Any opacification of the normally clear crystalline lens of the eye. Many are small and nonprogressive and do not cause visual symptoms. Cataracts that are clinically significant and decrease visual acuity in children represent a major challenge.
Cataract - general prevention
There is currently no known way to prevent congenital cataracts other than correcting any underlying metabolic abnormality if present. It is, however, essential that all newborns (and all children) receive screening eye examinations by nurses, pediatricians, or family practitioners. In many parts of the world, early diagnosis and referral is still the limiting factor for a child’s ultimate visual prognosis.
Cataract - epidemiology
Estimated to cause between 10% and 40% of all blindness in children worldwide
Cataract - prevalence
The prevalence of infantile cataracts has been reported to be as high as 6 to as low as 1.2 cases per 10,000 births.
Cataract - risk factors
Cataract - genetics
Infantile cataracts may be inherited as autosomal dominant, autosomal recessive, or X-linked recessive traits. Autosomal dominant cataracts are most commonly bilateral nuclear opacities but marked variability can be present even within the same pedigree. Multiple genes are involved in lens development, and numerous genetic loci have been identified. Infantile cataracts also occur in association with a number of syndromes.
Cataract - pathophysiology
- Derangement of the normal developmental growth of the crystalline fibers of the central lens nucleus or peripheral lens cortex; the location of the opacity often suggests the gestational age at which it occurred.
- Frequently classified according to morphology or etiology
- Dense central opacities of ≥3 mm usually produce substantial visual disability.
Cataract - etiology
- Of congenital cataracts, ~1/3 are inherited; 1/3 are associated with systemic genetic, metabolic, or maternal infectious disorders; and ~1/3 are idiopathic (cause unknown).
- A small number of cataracts are associated with other primary inherited ocular abnormalities.
- Developmental cataracts may result from metabolic disorders, toxic agents (steroids, radiation), and localized trauma.
Cataract - associated conditions
- Maternal infections, such as the TORCH (toxoplasmosis, other infections, rubella, toxoplasmosis, cytomegalovirus, and herpes simplex) syndrome, especially congenital rubella
- Metabolic and endocrine disorders such as galactosemia, neonatal hypoglycemia, and diabetes mellitus
- Fetal alcohol syndrome
- Chromosomal disorders, e.g., Down syndrome, trisomies 13 or 15, Turner syndrome
- Many craniofacial and mandibulofacial syndromes
- Dermatologic entities such as congenital ichthyosis, hereditary ectodermal dysplasia, and infantile poikiloderma
- Skeletal disorders such as Marfan and Conradi syndromes
- Renal disorders such as Lowe and Alport syndromes
- Neurofibromatosis
- Myotonic dystrophy
- Fabry disease and hypoparathyroidism
- Local ocular disorders, including aniridia, many of the anterior chamber dysgenesis syndromes, blunt or penetrating trauma, and diseases associated with ocular inflammation (chronic iritis or uveitis), such as juvenile rheumatoid arthritis
Cataract - DIAGNOSIS
Cataract - signs & symptoms
Cataract - history
- Decreased visual responses?
- Cataracts may decrease vision.
- Sun sensitivity or squinting in bright light?
- Cataracts may cause glare and increase light sensitivity.
- Strabismus (ocular misalignment)?
- May indicate loss of vision in one eye.
- White pupil?
- White pupil cataracts appear as a white object in or under the pupil.
- Unequal or abnormal pupillary reflections (red eyes) with flash photography?
- Cataract will block the standard red reflex.
- Nystagmus?
- May be an ominous sign for the degree of vision loss.
- Careful family and prenatal history?
- Up to 1/3 of congenital cataracts are inherited.
- Positive family history or known history of a disorder associated with cataracts?
- See “Associated Conditions.”
Cataract - physical exam
- Decreased vision/visual acuity: Cataracts may cause decreased visual acuity.
- Strabismus: May indicate loss of vision in one eye
- White pupil (leukokoria) on flashlight examination: Cataracts may appear as a white pupil.
- Unequal, irregular, or poor red fundus reflections by direct ophthalmoscopy: Cataracts will interfere with seeing a red reflex.
- Presence or absence of nystagmus: Nystagmus is a poor prognostic sign.
- Bilaterality of disease: Bilateral cataracts are more likely to be secondary to systemic disease.
- Size of globe (eyeball): Microphthalmia (small eye) suggests congenital cataracts.
- Thorough exam for systemic syndromic findings: See “Associated Conditions.”
Cataract - tests
- Complete ophthalmic evaluation, including slit-lamp biomicroscopy and fundus examination
- Electrophysiologic analysis of the visual system can be helpful for visual potential.
Cataract - lab
A selective workup may be more indicated with bilateral cataracts and includes:
- TORCH titers, including syphilis
- Urine tests for reducing substance (galactosemia), protein, amino acids, and pH (Lowe syndrome)
- Blood glucose, calcium, phosphate
- Quantitative amino acids and RBC enzyme levels (galactokinase, gal-1-uridyltransferase)
- Genetic consultation, chromosome analysis, and ocular examination of parents and siblings
Cataract - imaging
Ultrasonography if unable to visualize ocular structures behind the opacity
Cataract - differencial diagnosis
- The differential diagnosis of childhood cataracts is more concerned with the underlying cause of leukokoria (white pupil) rather than the presence of some other entity, as the cataract itself is readily identified on examination by the ophthalmologist.
- Retinoblastoma, retinopathy of prematurity, juvenile retinoschisis, persistent hyperplastic primary vitreous, severe uveitis, and retinal detachment all may cause primary leukokoria or a cataract, which itself may produce leukokoria.
- Cataracts may also be an expression of a more severe, underlying systemic disease, which needs to be diagnosed to benefit the child’s overall health.
Cataract - TREATMENT
Cataract - general measures
- In the case of a monocular, small cataract, sometimes simple pharmacologic pupillary dilatation of the affected eye and occlusion of the noncataractous eye help to overcome mild amblyopia and preserve acceptable vision without surgical removal of the cataract. Glasses may or may not be of additional help.
- Small cataracts may progress, so nonsurgical treatments require close patient follow-up.
- Visually significant cataracts must be removed surgically. However, without optical correction of the operated, aphakic (lensless) eye, visual rehabilitation is impossible.
- <1 year, optical correction of bilateral aphakia is most frequently accomplished with contact lenses or spectacles. In unilateral cataract cases, successful visual rehabilitation always requires extensive occlusion therapy to the normal eye for years. In these cases, optical correction of the unilateral aphakia is best obtained with a contact lens. Even when visual rehabilitation of monocular aphakia is successful, normal binocular vision with preserved depth perception is unlikely.
- In children >1 year, especially those with unilateral cataracts, intraocular lenses (IOLs) have, in appropriate cases, proved successful and are now being used frequently. They can afford faster visual rehabilitation and increased chances of normal binocular vision.
- Refractive corneal surgery for optical correction of aphakia is not indicated in children at this time.
Cataract - FOLLOW UP
- Without treatment, visually significant cataracts result in progressive visual loss. When an opacity is present at birth or very early in life, the visual loss quickly becomes irreversible.
- Once surgical removal is performed and optical correction is started, the child, parents, and physician enter into an intensive and long rehabilitation period, lasting until visual maturity and stability are reached (usually around 7–10 years of age). After this point, yearly eye examinations are a minimum requirement.
- Parental and educational support services may be needed for those with residual visual handicap.
- Special local, state, and federal services for the visually handicapped and blind may be required, as not all children who have successful surgical results will have good vision.
Pitfalls:
- Lack of early diagnosis, referral, and treatment
- Lack of understanding of irreversible deprivation amblyopia
- Lack of compliance with postoperative optical correction and occlusion therapy
Cataract - prognosis
- Before 1980, most children treated for monocular cataracts had their best corrected vision only in the 20/200–20/800 range and children with bilateral cataracts obtained best corrected acuities in the 20/80–20/200 range.
- Earlier surgery, better surgical techniques, and rapid postsurgical optical correction now frequently afford corrected visual acuities of 20/40–20/200 for monocular cataracts and 20/40 or better for bilateral cataracts.
- Successful treatment of pediatric cataracts may be extremely difficult, and intervention must occur very early in life in the case of congenital cataracts or as soon as possible in later-onset cataracts.
- Useful vision can be restored or obtained in newborns with unilateral cataracts if the surgery is completed within the 1st 6 weeks of life. After this time, visual restoration becomes progressively more difficult, again because of irreversible deprivation amblyopia.
- The prognosis for visual rehabilitation in children with bilateral congenital cataracts is slightly better, providing surgical removal and optical correction are accomplished early, preferably by 2 months of age.
- Although later-onset cataracts have a better prognosis because the visual system has developed to some degree, these children still require immediate evaluation and treatment.
- In all cases, the onset or presence of nystagmus before the cataract is removed is an ominous sign of poor outcome and adds further urgency to the need for surgical removal.
- Family compliance with both postsurgical optical correction and amblyopia treatment is critical and directly affects the child’s ultimate visual outcome later in life.
Cataract - complications
- Lack of removal of a visually significant cataract at the appropriate time leads to irreversible deprivation amblyopia, in which case no amount of surgery, optical correction, or amblyopia therapy is of benefit.
- Surgical removal of a cataract in children previously left the eye without a lens (aphakic) and unable to focus without some type of optical correction (spectacles or contact lenses). Unless rapid restoration of optical correction occurs, irreversible deprivation amblyopia may still occur after the cataract is removed, particularly if the cataract is unilateral. The aphakic pediatric eye is also more prone than an anatomically normal eye to elevated intraocular pressures (glaucoma) and early retinal detachments, either of which may cause permanent visual loss.
- More recently, intraocular lenses have become an accepted means of optical rehabilitation in children >1 year of age. Multicenter studies are under way to evaluate the use of intraocular lenses in younger children.
Cataract - bibliography
- Amaya L, Taylor D, Russell-Eggitt I, et al. The morphology and natural history of childhood cataracts. Surv Ophthalmol. 2003;48:125–144.
Childhood cataracts and other lens disorders. In: Simon JW, et al., eds. Pediatric Ophthalmology and Strabismus: Basic and Clinical Science Course, Section 6. San Francisco: American Academy of Ophthalmology; 2003–2004:271–282.- Gimbel HV, Basti S, Ferensowicz M, et al. Results of bilateral cataract extraction with posterior chamber intraocular lens implantation in children. Ophthalmology. 1997;104:1737–1743.
- Lambert SR, Drack AV. Infantile cataracts. Surv Ophthalmol. 1996;40:427–458.
- Levin AV. Congenital eye anomalies. Pediatr Clin North Am. 2003;50:55–76.
- Wilson ME Jr, Trivedi RH, Hoxie JP, et al. Treatment outcomes of congenital monocular cataracts: The effects of surgical timing and patching compliance. J Pediatr Ophthalmol Strabismus. 2003;40:323–329; quiz 353–354.
- Wilson ME, Pandey SK, Thakur J. Pediatric cataract blindness in the developing world: Surgical techniques and intraocular lenses in the new millennium. BJO. 2003;87:14–19.
- Zwann J, Mullaney PB, Awad AA, et al. Pediatric intraocular lens implantation: Surgical results and complications in more than 300 cases. Ophthalmology. 1998;105:112–119.
Cataract - CODES
Cataract - icd9
- 366.00 Unspecified nonsenile cataract
- 366.04 Nuclear cataract, nonsenile
- 366.13 Anterior subcapsular polar senile cataract
- 366.14 Posterior subcapsular polar senile cataract
- 743.30 Childhood cataract
Cataract - FAQ
- Q: Is surgical removal of the cataract a visual cure?
- A: No. Surgery is only the beginning of treatment, which also includes optical correction and amblyopia therapy.
- Q: Once the cataract is removed, will intensive, extensive follow-up be needed?
- A: Yes. The visual prognosis is directly related to postsurgical treatment compliance.
- Q: Is the cataract easier to treat when the child is older?
- A: No. Irreversible deprivation amblyopia develops as the child grows, precluding any chance for normal vision.
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Book Source Details
- Book Title: The 5-Minute Pediatric Consult
- Author(s): M. William Schwartz MD; et al.
- Year of Publication: 2008
- Copyright Details: The 5-Minute Pediatric Consult, Copyright © 2008 Lippincott Williams & Wilkins.
Other Book Chapters Related to Cataract
Read excerpts from these other book chapters related to Cataract:
Medical Books Excerpts
- Cataract
- "Professional Guide to Diseases (Eighth Edition)" (2005)
- [ read ]
Copyright Details: The 5-Minute Pediatric Consult, Copyright © 2008 Williams & Wilkins.
More About Causes of Cataract
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More About This Book:
Title: The 5-Minute Pediatric Consult
Authors: M. William Schwartz MD; et al.
Publisher: Lippincott Williams & Wilkins
Copyright: 2008
ISBN: 0-7817-7577-9
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