eMedicine Specialties > Ophthalmology > Lens

Cataract, Congenital

Mounir Bashour, MD, CM, FRCS(C), PhD, FACS, Assistant Professor of Ophthalmology, McGill University; Clinical Assistant Professor of Ophthalmology, Sherbrooke University; Medical Director, Cornea Laser and Lasik MD
Johanne Menassa, MD, Staff Physician, Department of Ophthalmology, University of Laval Hospital, Quebec City; C Corina Gerontis, MD, Consulting Staff, Departments of Pediatrics and Ophthalmology, Schneider Children's Hospital/Long Island Jewish Medical Center

Updated: Jun 8, 2009

Introduction

Background

A cataract is an opacification of the lens. Congenital cataracts usually are diagnosed at birth. If a cataract goes undetected in an infant, permanent visual loss may ensue. Not all cataracts are visually significant. If a lenticular opacity is in the visual axis, it is considered visually significant and may lead to blindness. If the cataract is small, in the anterior portion of the lens, or in the periphery, no visual loss may be present.

Unilateral cataracts are usually isolated sporadic incidents. They can be associated with ocular abnormalities (eg, posterior lenticonus, persistent hyperplastic primary vitreous, anterior segment dysgenesis, posterior pole tumors), trauma, or intrauterine infection, particularly rubella.

Bilateral cataracts are often inherited and associated with other diseases. They require a full metabolic, infectious, systemic, and genetic workup. The common causes are hypoglycemia, trisomy (eg, Down, Edward, and Patau syndromes), myotonic dystrophy, infectious diseases (eg, toxoplasmosis, rubella, cytomegalovirus, and herpes simplex [TORCH]), and prematurity.

Pathophysiology

The lens forms during the invagination of surface ectoderm overlying the optic vesicle. The embryonic nucleus develops by the sixth week of gestation. Surrounding the embryonic nucleus is the fetal nucleus. At birth, the embryonic and fetal nuclei make up most of the lens. Postnatally, cortical lens fibers are laid down from the conversion of anterior lens epithelium into cortical lens fibers.

The Y sutures are an important landmark because they identify the extent of the fetal nucleus. Lens material peripheral to the Y sutures is lens cortex, whereas lens material within and including the Y sutures is nuclear. At the slit lamp, the anterior Y suture is oriented upright, and the posterior Y suture is inverted.

Any insult (eg, infectious, traumatic, metabolic) to the nuclear or lenticular fibers may result in an opacity (cataract) of the clear lenticular media. The location and pattern of this opacification may be used to determine the timing of the insult as well as the etiology.

Frequency

United States

Incidence is 1.2-6 cases per 10,000.

International

Incidence is unknown. Although the World Health Organization and other health organizations have made outstanding strides in vaccinations and disease prevention, the rate of congenital cataracts is probably much higher in underdeveloped countries.

Mortality/Morbidity

Visual morbidity may result from deprivation amblyopia, refractive amblyopia, glaucoma (as many as 10% post surgical removal), and retinal detachment.
Metabolic and systemic diseases are found in as many as 60% of bilateral cataracts.
Mental retardation, deafness, kidney disease, heart disease, and other systemic involvement may be part of the presentation.

Age

Congenital cataracts usually are diagnosed in newborns.

Clinical

History

Congenital cataracts are present at birth but may not be identified until later in life. Prenatal and family history is helpful.
Some cataracts are static, but some are progressive. This explains why not all congenital cataracts are identified at birth.
Anterior polar cataract and nuclear cataract are usually static, although they may rarely progress.
Cataracts that typically progress include posterior lenticonus, persistent hyperplastic primary vitreous, lamellar, sutural, and anterior or posterior subcapsular. They usually have a better prognosis because they only usually begin to obstruct the vision after the critical period of visual development has passed.
Not all cataracts are visually significant. If a lenticular opacity is in the visual axis, it usually is considered visually significant and requires removal.
Cataracts in the center of the visual axis that are greater than 3 mm in diameter are generally considered visually significant. This principle is furthermore correlated with the clinical ophthalmological examination of the patient.
A study by the Department of Pediatric Ophthalmology of the Wills Eye Hospital concluded that, in terms of the risk factor for amblyopia, more important than the cataract size is the anisometropia induced by the congenital anterior lens opacities (CALOs).¹ Patients with CALOs who have anisometropia of 1 diopter (D) or more are 6.5 times more likely to develop amblyopia.¹

Physical

A lenticular opacity is called a cataract. Not all cataracts are visually significant.
Description of a congenital cataract must include location, color, density, and shape for purposes of identification.
An irregular red reflex is the hallmark of visual problems. If an irregular red reflex is detected at the initial screening, this is usually an indication that a congenital cataract might be present and an ophthalmology consultation is warranted.
Leukocoria or white reflex can be the presenting sign of a cataract. In fact, in a 2008 study by Haider et al, 60% of patients who presented with leukocoria had congenital cataracts (18% unilateral and 42% bilateral).² Other causes included retinoblastoma (11% unilateral and 7% bilateral), retinal detachment (2.8% unilateral and 1.4% bilateral), bilateral persistent hyperplastic primary vitreous (4.2%), and unilateral Coats disease (4.2%).²
Slit lamp examination of both eyes (dilated pupil) not only may confirm the presence of a cataract but also may identify the time when the insult occurred in utero and if there is other systemic or metabolic involvement.
Dilated fundus examination is recommended as part of the ocular examination for both unilateral cataract cases and bilateral cataract cases.

Causes

The most common etiology includes intrauterine infections, metabolic disorders, and genetically transmitted syndromes. One third of pediatric cataracts are sporadic; they are not associated with any systemic or ocular diseases. However, they may be spontaneous mutations and may lead to cataract formation in the patient's offspring. As many as 23% of congenital cataracts are familial. The most frequent mode of transmission is autosomal dominant with complete penetrance. This type of cataract may appear as a total cataract, polar cataract, lamellar cataract, or nuclear opacity. All close family members should be examined.
Infectious causes of cataracts include rubella (the most common), rubeola, chicken pox, cytomegalovirus, herpes simplex, herpes zoster, poliomyelitis, influenza, Epstein-Barr virus, syphilis, and toxoplasmosis.

Differential Diagnoses

Retinoblastoma

Workup

Laboratory Studies

For unilateral cataracts, laboratory studies include TORCH titers and Venereal Disease Research Laboratory (VDRL) test.
For bilateral cataracts, laboratory studies include CBC, BUN, TORCH titers, VDRL, urine for reducing substances, red cell galactokinase, urine for amino acids, calcium, and phosphorus.

Imaging Studies

CT scan of brain

Other Tests

Hearing test

Treatment

Medical Care

Medical therapy is directed at the prevention of amblyopia.

Surgical Care

Cataract surgery is the treatment of choice and should be performed when patients are younger than 17 weeks to ensure minimal or no visual deprivation. Most ophthalmologists opt for surgery much earlier, ideally when patients are younger than 2 months, to prevent irreversible amblyopia and sensory nystagmus in the case of bilateral congenital cataracts. The delay in surgery is because of glaucoma. Since glaucoma occurs in 10% of congenital cataract surgery, many surgeons delay the cataract surgery.
- Unfortunately, the improved surgical techniques of the 1990s have not lowered the incidence of glaucoma from the series published in the 1980s. The development of glaucoma (which occurs in later years) only occurs in cataract eyes that undergo surgery. This may be in part due to the immaturity of the angle at the time of surgery. A delay of a few weeks allows the angle of the immature eye to develop.
- Koc and colleagues concluded that early age at cataract extraction and microcornea are risk factors for delayed-onset glaucoma.³
Extracapsular cataract extraction with primary posterior capsulectomy and anterior vitrectomy is the procedure of choice (via limbal or pars plana approach). Intracapsular cataract extraction in children is contraindicated because of vitreous traction and loss at the Wieger capsulohyaloid ligament. Vitrectomy instrumentation is the preferred method since the lens material is very soft. The whole procedure can be performed using one intraocular instrument. Young eyes develop capsular opacification very quickly, necessitating primary capsulectomy at the time of cataract extraction.
A study is underway in the United States to determine if intraocular lens placement in children younger than 6 months is a viable option. (Several articles have already been published in British journals.)
A study by the Retina Foundation of the Southwest in Texas compared intraocular lens (IOL) implantation with aphakic contact lenses (CLs) after the extraction of a unilateral cataract.⁴ Patients were as young as 6 months. They concluded that IOLs and aphakic CLs support similar visual acuity development after surgery for a unilateral cataract. IOLs may support better visual acuity development when compliance with CL wear is moderate to poor or when a cataract is extracted in a patient older than 1 year.
A study with promising preliminary results concerns the primary implantation of flexible IOLs in infants younger than 1 year.⁵ The population studied includes infants aged 3-11 months who have different forms of unilateral congenital cataracts.
A 2008 study by Capozzi and colleagues showed that, in the first 42 months of age, corneal power (Km) and axial length (AL) values are significantly different according to age.⁶ These findings have implications for the calculation of IOL power. Km values were significantly greater, and AL readings were shorter, in younger children (p<0.001). No differences according to gender were found. As a group, eyes from unilateral cataract cases had significantly longer AL readings than those from bilateral cataract cases (p=0.029). In a small subgroup of unilateral cataract cases, for which readings from the clear lens eye were available (n. 39), Km values of the affected eye were significantly greater than that of the fellow healthy eye (p=0.007).

Consultations

An ophthalmology consultation is essential to prevent visual loss as well as to make the appropriate diagnosis of the type of cataract.
A genetics evaluation is warranted if bilateral cataracts or any other anomalies are present.

Diet

Restriction of galactose, if galactosemia is present, may reverse the progression of the classic "oil droplet" cataract.

Follow-up

Deterrence/Prevention

A red reflex is essential not only in the newborn nursery but also in all office visits.
Frequent eye examinations help in the prevention of amblyopia.
Frequent glaucoma screenings are needed throughout the patient’s lifetime.

Complications

Loss of vision even with aggressive surgical and optical treatment
Amblyopia
Glaucoma
Strabismus
Retinal detachment

Prognosis

Of persons with unilateral congenital cataracts, 40% develop visual acuity of 20/60 or better.
Of persons with bilateral congenital cataracts, 70% develop visual acuity of 20/60 or better.
The prognosis is poorer in persons with other ocular or systemic involvement.

Patient Education

Removal of the cataract is only the beginning. Visual rehabilitation requires many years of refractive correction (eg, contact lenses, aphakic glasses), possible patching for amblyopia, possible strabismus surgery, and glaucoma screenings.
Patients must be made aware of the risk of potential visual loss from amblyopia, retinal detachment, or glaucoma.
Repeated surgical procedures, including a secondary lens implant if other modalities of refractive correction fail, may be needed.
If this is a de novo chromosomal change or a familial abnormality, all siblings and future offspring are at risk.
For excellent patient education resources, visit eMedicine's Eye and Vision Center. Also, see eMedicine's patient education article Cataracts.

Miscellaneous

Medicolegal Pitfalls

Since there is a high association of systemic and metabolic abnormalities, genetic consultation is essential for those patients with bilateral cataracts. Some diseases may be preventable if diagnosis is made early.

References

Ceyhan D, Schnall BM, Breckenridge A, et al. Risk factors for amblyopia in congenital anterior lens opacities. J AAPOS. Dec 2005;9(6):537-41. [Medline].
Haider S, Qureshi W, Ali A. Leukocoria in children. J Pediatr Ophthalmol Strabismus. May-Jun 2008;45(3):179-80. [Medline].
Koc F, Kargi S, Biglan AW, et al. The aetiology in paediatric aphakic glaucoma. Eye. Dec 2006;20(12):1360-5. [Medline].
Birch EE, Cheng C, Stager DR Jr, et al. Visual acuity development after the implantation of unilateral intraocular lenses in infants and young children. J AAPOS. Dec 2005;9(6):527-32. [Medline].
Sidorenko EI, Shirshov MV, Korkh NL. [Preliminary results of primary implantation of flexible intraocular lenses in infants under 1 year of age]. Vestn Oftalmol. Sep-Oct 2005;121(5):37-8. [Medline].
Capozzi P, Morini C, Piga S, et al. Corneal Curvature and Axial Length values in children with Congenital/Infantile Cataract in the first 42 Months of life. Invest Ophthalmol Vis Sci. May 23 2008;[Medline].
Biglan AW, Cheng KP, Davis JS, et al. Secondary intraocular lens implantation after cataract surgery in children. Am J Ophthalmol. Feb 1997;123(2):224-34. [Medline].
Brady KM, Atkinson CS, Kilty LA, e al. Cataract surgery and intraocular lens implantation in children. Am J Ophthalmol. Jul 1995;120(1):1-9. [Medline].
Buckley E, Lambert SR, Wilson ME. IOLs in the first year of life. J Pediatr Ophthalmol Strabismus. Sep-Oct 1999;36(5):281-6. [Medline].
Cassidy L, Taylor D. Congenital cataract and multisystem disorders. Eye. Jun 1999;13 (Pt 3b):464-73. [Medline].
Cheng KP, Hiles DA, Biglan AW, et al. Management of posterior lenticonus. J Pediatr Ophthalmol Strabismus. May-Jun 1991;28(3):143-9; discussion 150. [Medline].
Mori M, Keech RV, Scott WE. Glaucoma and ocular hypertension in pediatric patients with cataracts. J AAPOS. Jun 1997;1(2):98-101. [Medline].

Keywords

congenital cataract, congenital cataracts, cataract extraction, cataract surgery, deprivation amblyopia, refractive amblyopia, glaucoma, vision loss, visual deficit, blindness, rubella

Contributor Information and Disclosures

Author

Mounir Bashour, MD, CM, FRCS(C), PhD, FACS, Assistant Professor of Ophthalmology, McGill University; Clinical Assistant Professor of Ophthalmology, Sherbrooke University; Medical Director, Cornea Laser and Lasik MD
Mounir Bashour, MD, CM, FRCS(C), PhD, FACS is a member of the following medical societies: American Academy of Ophthalmology, American Association for Pediatric Ophthalmology and Strabismus, American College of International Physicians, American College of Surgeons, American Medical Association, American Society of Cataract and Refractive Surgery, American Society of Mechanical Engineers, American Society of Ophthalmic Plastic and Reconstructive Surgery, Biomedical Engineering Society, Canadian Medical Association, Canadian Ophthalmological Society, Contact Lens Association of Ophthalmologists, International College of Surgeons US Section, Ontario Medical Association, Quebec Medical Association, and Royal College of Physicians and Surgeons of Canada
Disclosure: Nothing to disclose.

Coauthor(s)

Johanne Menassa, MD, Staff Physician, Department of Ophthalmology, University of Laval Hospital, Quebec City
Disclosure: Nothing to disclose.

C Corina Gerontis, MD, Consulting Staff, Departments of Pediatrics and Ophthalmology, Schneider Children's Hospital/Long Island Jewish Medical Center
C Corina Gerontis, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Ophthalmology, American Association for Pediatric Ophthalmology and Strabismus, and American Medical Association
Disclosure: Nothing to disclose.

Medical Editor

Richard W Allinson, MD, Associate Professor, Department of Surgery, Texas A&M University Health Science Center; Senior Staff Ophthalmologist, Scott and White Clinic
Richard W Allinson, MD is a member of the following medical societies: American Academy of Ophthalmology, American Medical Association, and Texas Medical Association
Disclosure: Nothing to disclose.

Pharmacy Editor

Simon K Law, MD, PharmD, Assistant Professor of Ophthalmology, Jules Stein Eye Institute; Chief of Section of Ophthalmology Surgical Services, Department of Veterans Affairs Healthcare Center, West Los Angeles
Simon K Law, MD, PharmD is a member of the following medical societies: American Academy of Ophthalmology, American Glaucoma Society, and Association for Research in Vision and Ophthalmology
Disclosure: Nothing to disclose.

Managing Editor

J James Rowsey, MD, Former Director of Corneal Services, St Luke's Cataract and Laser Institute, Florida
J James Rowsey, MD is a member of the following medical societies: American Academy of Ophthalmology, American Association for the Advancement of Science, American Medical Association, Association for Research in Vision and Ophthalmology, Florida Medical Association, Pan-American Association of Ophthalmology, Sigma Xi, and Southern Medical Association
Disclosure: Nothing to disclose.

CME Editor

Lance L Brown, OD, MD, Ophthalmologist, Affiliated With Freeman Hospital and St John's Hospital, Regional Eye Center, Joplin, Missouri
Disclosure: Nothing to disclose.

Chief Editor

Hampton Roy Sr, MD, Associate Clinical Professor, Department of Ophthalmology, University of Arkansas for Medical Sciences
Hampton Roy Sr, MD is a member of the following medical societies: American Academy of Ophthalmology, American College of Surgeons, and Pan-American Association of Ophthalmology
Disclosure: Nothing to disclose.

Further Reading