Cataract in children

INTRODUCTION — A cataract is an opacity of the lens of the eye that causes partial or total visual loss (picture 1). Cataracts are a common and frequently curable cause of blindness in children. Early detection and prompt intervention are critical for a good visual outcome, particularly in newborns.

Cataracts in infants and children will be reviewed here. Lens dislocation in children and cataracts in adults are discussed separately. (See "Ectopia lentis (dislocated lens) in children" and "Cataract in adults".)

EPIDEMIOLOGY — The reported prevalence of childhood cataracts ranges from 1 to 15 per 10,000 children. The wide range reflects differences in populations, age groups, methods of ascertainment, and case definitions [1]. The prevalence of congenital cataract in developed countries is 1 to 3 per 10,000 [1-4].

ANATOMY — The crystalline lens consists of five major structures: embryonic nucleus, fetal nucleus, cortex, lens epithelium, and lens capsule. The crystalline lens focuses light rays onto the retina [5]. Relaxation or contraction of the ciliary body changes the shape of the lens to permit focus of light rays from objects at distant and near fixation (figure 1). Contraction of the ciliary body to permit focus at near fixation is referred to as "accommodation."

CLASSIFICATION — Cataracts are usually classified according to their location in the lens (figure 2), morphologic appearance (table 1), and/or underlying pathology [5,6]:

●Congenital anterior polar cataracts – Congenital anterior polar cataracts are typically (though not always) bilateral, symmetrical, small opacities involving the anterior lens capsule that are usually nonprogressive (picture 2). They are frequently familial. Congenital anterior polar cataracts generally are associated with a good visual prognosis but may be progressive and should be followed [7,8]. If a congenital anterior polar cataract is unilateral, it is frequently associated with anisometropia, which, in turn, can cause amblyopia. (See "Amblyopia in children: Classification, screening, and evaluation", section on 'Etiology and classification'.)

●Persistent fetal vasculature (PFV) – PFV (formerly called persistent hyperplastic primary vitreous) is an arrest of embryonic development. The eye is mildly microphthalmic (picture 3), and a vascularized stalk extends from the optic nerve to the posterior aspect of the crystalline lens, causing a posterior lens plaque that can obstruct the visual axis. PFV may result in cataract formation, elongation of the ciliary processes, and glaucoma [9]. Cataract surgery in children with PFV often is complicated. Visual prognosis may be limited by associated optic nerve or macular disease [10].

●Congenital posterior polar cataract – Congenital posterior polar cataract may be unilateral or bilateral.

•A unilateral posterior polar cataract (Mittendorf dot) is a remnant of the primary vitreous (mild form of PFV) and is generally nonprogressive

•Bilateral posterior polar cataracts may be familial or sporadic and usually are progressive

●Posterior lenticonus or lentiglobus – Posterior lenticonus and posterior lentiglobus refer to congenital defects of the posterior lens capsule that respectively cause a conical (picture 4) or spherical bulge in the capsule and progressive cataract formation. The progression may take months to years; slow progression is usually associated with good visual prognosis.

●Posterior subcapsular cataracts – Posterior subcapsular cataracts involve the area immediately anterior to the posterior capsule (figure 2). They are acquired, in many cases, secondary to glucocorticoid therapy or ionizing radiation.

●Total cataracts – Total (complete or diffuse) cataracts involve the complete crystalline lens (picture 1) and preclude any view of the retina.

●Zonular cataracts – Zonular cataracts involve a particular zone of the developing lens (nuclear, lamellar, sutural, or cortical) and reflect an insult occurring at a particular time during lens development. Nuclear cataracts occur early in gestation, whereas lamellar cataracts occur in childhood.

•Nuclear cataracts involve the embryonal or fetal nucleus and are highly amblyogenic. They usually are bilateral, can represent an intrauterine insult, and often are associated with microphthalmos (picture 5). Bilateral cases may be associated with autosomal dominant inheritance [11].

•Lamellar cataracts involve the lamella peripheral to the Y sutures of the lens (which is the area where lens fibers meet and interdigitate near the anterior and posterior poles of the crystalline lens).

•Sutural cataracts involve the Y sutures of the lens and can be unilateral or bilateral, and inheritance is X-linked or autosomal recessive.

ETIOLOGY — Approximately one-third of congenital cataracts in children are inherited, one-third are associated with systemic diseases, and one-third are idiopathic or sporadic.

Hereditary — Hereditary cataracts account for approximately 10 to 25 percent of congenital cataracts [12]. The inheritance pattern is most commonly autosomal dominant, with almost complete penetrance but variable expressivity. Autosomal recessive and X-linked forms are less frequent. Hereditary cataracts may be present at birth or develop over time; they may be sutural, anterior or posterior capsular/polar. (See 'Classification' above.)

Slit lamp examination of the birth parent(s) will occasionally reveal subtle lenticular changes, which could point to an inherited etiology. Infants and children with a family history of childhood-onset cataracts should be referred to an ophthalmologist.

Disease-associated — The list of systemic and ocular disorders in which cataracts occur is extensive (table 2). All children with such disorders warrant ophthalmic evaluation. (See 'Evaluation' below.)

Ocular trauma — Opacity of the lens may be an immediate, early, or late complication of ocular trauma (picture 6) [13]. Most of the injuries that result in traumatic cataract occur during play or sports-related activity and often involve projectiles [13,14]. Penetrating injuries are more commonly associated with cataracts than blunt injuries. (See "Open globe injuries: Emergency evaluation and initial management".)

Cataracts due to blunt trauma usually are stellate- or rosette-shaped and may be stable or progressive [13]. Penetrating trauma with disruption of the lens capsule allows hydration of the lens cortex, which results in cataract; these cortical changes may remain focal (if small) or progress rapidly (within a period of hours) to total cortical opacification [13].

The possibility of nonaccidental injury should be considered in cases of total or complete cataracts where the etiology is unclear. (See "Physical child abuse: Recognition" and "Physical child abuse: Diagnostic evaluation and management".)

Glucocorticoids — The cataractogenic effects of systemic glucocorticoids are well documented. We recommend ophthalmologic evaluation for children receiving long-term systemic glucocorticoids or adrenocorticotropic hormone [15]. (See "Major adverse effects of systemic glucocorticoids", section on 'Ophthalmologic effects'.)

The risk of cataracts with inhaled glucocorticoids is not well established. We do not suggest ophthalmologic evaluation for children receiving only inhaled glucocorticoids. (See "Major side effects of inhaled glucocorticoids", section on 'Ocular effects'.)

Radiation — Ionizing radiation is a well-documented cause of cataracts. The pediatric lens is particularly susceptible. The minimum dose considered to be cataractogenic is 500 rad [16]. Children exposed to a lenticular dose of 1 Gy have a 50 percent increased incidence of cataract formation [17]. Children who have undergone cranial or total-body irradiation should have eye examinations performed annually. (See "Delayed complications of cranial irradiation", section on 'Cataracts'.)

Low birth weight — Bilateral congenital cataracts have been reported in infants with low birth weight (<2000 g) [18].

CLINICAL FEATURES

Presentation — Infants and children with cataracts may present with any or all of the following:

●Parental complaint – Cataracts that involve the anterior portion of the lens can be seen by the unaided eye. Such cataracts often are first noted by a parent [5]. This is the most common presentation for anterior polar cataracts.

●Family history – Infants with a family history of childhood-onset cataracts should be referred to an ophthalmologist. Hereditary cataracts most commonly have an autosomal dominant inheritance pattern. Cataracts may be present at birth or develop over time. Timely referral to an ophthalmologist allows for early diagnosis and treatment. (See 'Hereditary' above and 'Referral indications' below.)

●Poor vision – Poor vision in infants is manifest by visual behavior that deviates from normal (table 3).

●Asymmetry of the red reflex – Simultaneous red reflex examination (Bruckner testing) is a simple test to detect cataracts in infancy and childhood (figure 3) [19]. Evaluation of the red reflex in old photographs of the child may help determine the age of onset of the cataract and aid in providing the family/caregivers with a visual prognosis. (See 'Prognosis' below.)

●Leukocoria (white pupillary reflex) – Other causes of leukocoria include retinoblastoma, Coats disease, toxocariasis, persistent fetal vasculature (PFV), or retinal coloboma. (See "Approach to the child with leukocoria".)

●Nystagmus – Nystagmus can result from visual deprivation in the first months of life; it is associated with a poor visual prognosis [2,20]. In children with congenital cataracts, nystagmus develops at two to three months of age. Children who develop cataracts after six months of age usually do not have nystagmus.

●Strabismus – Children with cataracts can present with strabismus [2]. Strabismus may not develop until irreversible visual loss has occurred. (See "Causes of horizontal strabismus in children", section on 'Sensory esotropia' and "Evaluation and management of strabismus in children", section on 'Causes'.)

●Photophobia – The glare caused by the scattering of light from some types of cataract may result in photophobia [5].

●Delayed development – Infants with significant bilateral congenital cataracts may have delayed attainment of developmental milestones [2,21].

●Extraocular findings – Children with systemic diseases or multisystem genetic disorders may present with signs and symptoms unrelated to the cataract. For example, a boy with Fabry disease may present with neuropathic limb pain and characteristic skin findings (picture 7A-B); an infant with a congenital infection may present with low birth weight, microcephaly, hepatomegaly, skin lesions, and/or hearing impairment (table 4); an infant with Down syndrome may present with characteristic dysmorphic features and congenital heart disease. In these circumstances, cataracts may be detected on routine ophthalmologic examination performed as part of the comprehensive evaluation. (See "Fabry disease: Clinical features and diagnosis" and "Overview of TORCH infections" and "Down syndrome: Clinical features and diagnosis".)

Natural history — Cataracts may be stationary or progressive. Although certain types of cataracts tend to be stationary and others progressive, any type can progress. All cataracts should be followed for progression, especially during the early amblyogenic period, from birth to age five years, when amblyopia is most likely to result in visual loss and is most responsive to treatment. Cataracts occurring at a later age can also result in amblyopia but to a lesser extent. (See "Amblyopia in children: Classification, screening, and evaluation", section on 'Deprivation amblyopia'.)

Complications — Cataracts are one of the leading causes of visual impairment in children as they interfere with normal visual development [22,23]. Visual development occurs from birth to approximately eight years of age, with the majority occurring in the first three years of life. (See "Vision screening and assessment in infants and children", section on 'Visual development'.)

During this critical period of visual development, any reduction of retinal stimulation results in amblyopia. In children with cataracts, the degree of amblyopia depends upon the density of the cataract and its age of onset. The earlier the onset of lens opacification and the denser the opacification, the deeper the resultant amblyopia. Visually significant cataracts that are present in the first six months of life are a true ophthalmic emergency. If left untreated, they will result in irreversible visual loss. (See "Amblyopia in children: Classification, screening, and evaluation", section on 'Deprivation amblyopia'.)

EVALUATION — The evaluation of an infant or child with a cataract focuses on determining the etiology of the cataract, assessing the child's visual acuity, characterizing the cataract morphology, and identifying coexisting eye disease. Identification of associated systemic disease (table 2) may have important management implications (eg, galactosemia). Cataract is rarely the only manifestation of systemic disease [5]. In most cases, the underlying etiology can be determined by the history, physical examination, and ophthalmologic examination. If the cause remains uncertain, additional evaluation may be warranted. (See 'Etiologic evaluation' below.)

History — Important aspects of the history include:

●Age at onset of visual loss

●Family history of childhood-onset cataracts

●Ocular trauma

●Metabolic disorder such as galactosemia or diabetes (see "Galactosemia: Clinical features and diagnosis" and "Epidemiology, presentation, and diagnosis of type 1 diabetes mellitus in children and adolescents")

●History of systemic glucocorticoid use (see 'Glucocorticoids' above)

●History of cranial or total-body irradiation (see 'Radiation' above)

●Intrauterine infection (toxoplasmosis, rubella, cytomegalovirus, herpes simplex virus, varicella, syphilis) [24,25] (see "Overview of TORCH infections", section on 'Clinical features of TORCH infections')

●Chromosomal defect (eg, trisomy 21, 13, and 18) (see "Down syndrome: Clinical features and diagnosis" and "Congenital cytogenetic abnormalities", section on 'Trisomy 13 syndrome' and "Congenital cytogenetic abnormalities", section on 'Trisomy 18 syndrome')

Examination

●General examination – The general examination should evaluate for physical findings of associated systemic diseases or syndromes associated with cataracts. Some physical findings may provide clues to the underlying etiology, as summarized in the tables (table 4 and table 5).

●Eye examination – Eye examination by the primary care clinician should include assessment of the red reflex (simultaneous red reflex test [also known as Bruckner testing]), leukocoria, photophobia, extraocular movements, strabismus, nystagmus, and visual acuity. In patients with a history of ocular trauma, it is important to look for associated injuries. (See 'Presentation' above and 'Ocular trauma' above.)

Assessment of the red reflex is the most sensitive method of cataract detection. Simply evaluating the red reflex in both eyes simultaneously with a direct ophthalmoscope in a darkened room will reveal any significant lens opacity [5]. This can be performed with both a dilated and undilated pupil. Review of family photographs looking at the evolution of abnormalities in the red reflex over time provides valuable information about the onset of cataract, which has implications in the prognosis. (See 'Prognosis' below.)

In the preverbal child, visual acuity is assessed by the ability to fix and follow, fixation preference, or objection to occlusion of either eye. In the verbal child, visual acuity is assessed by optotype (Snellen) testing. The approach to vision assessment in infants and children is discussed in greater detail separately. (See "Vision screening and assessment in infants and children", section on 'Fixation reflex' and "Vision screening and assessment in infants and children", section on 'Optotype tests'.)

Etiologic evaluation — For many patients, additional evaluation is not necessary if the history and examination point to a specific etiology for the cataract (eg, a family history of heritable cataracts, associated ocular disease or trauma, glucocorticoid use, history of cranial irradiation, or obvious syndrome/chromosomal defect) (table 2).

If the etiology of the cataract is not explained by the history and examination, the evaluation may include:

●Testing for galactosemia and other inborn errors of metabolism (IEM) – In the United States and other countries where newborns are routinely screened for galactosemia, most affected children will be identified through early screening. However, if screening was not performed or there is clinical concern for galactosemia despite negative screening results, testing for galactosemia should be performed. Testing for IEM more broadly generally begins with plasma amino acids and urine organic acids. The approach to diagnostic testing for galactosemia and other IEMs is discussed in detail separately. (See "Galactosemia: Clinical features and diagnosis", section on 'Diagnosis' and "Inborn errors of metabolism: Identifying the specific disorder", section on 'Laboratory evaluation'.)

●Evaluation for congenital infection. (See "Overview of TORCH infections", section on 'Approach to the infant with suspected intrauterine infection'.)

●Evaluation for endocrinopathy (eg, diabetes mellitus, hypoparathyroidism) with blood glucose, hemoglobin A1c, calcium, and phosphate levels. (See "Epidemiology, presentation, and diagnosis of type 1 diabetes mellitus in children and adolescents" and "Hypoparathyroidism".)

●Karyotype and/or other genetic testing, which is guided by the clinical findings. Next-generation sequencing may play a role in the evaluation when the etiology remains uncertain despite more routine testing (eg, metabolic testing, TORCH titers, karyotyping). In one report of 14 children with bilateral congenital cataracts with no etiology identified on routine testing, the diagnostic yield of next-generation sequencing was 60 percent [26]. (See "Next-generation DNA sequencing (NGS): Principles and clinical applications".)

REFERRAL INDICATIONS — Referral to an ophthalmologist is essential for children in whom a cataract is suspected. Newborns and infants younger than one year of age should be seen as soon as possible because the risk of amblyopia increases if diagnosis is delayed. Older children should be seen within weeks of the primary care visit.

Referral to an ophthalmologist is also indicated for infants and children with:

●A family history of childhood-onset cataract

●Long-term systemic glucocorticoid use

●History of cranial irradiation

●Systemic disorder associated with cataracts (table 2)

DIAGNOSIS — The diagnosis of cataract is based on characteristic findings of opacity on comprehensive dilated ophthalmic examination. A complete eye examination by the ophthalmologist may require the use of sedation or general anesthesia and is often performed at the time of surgical intervention. Ancillary testing such as ocular ultrasound may be necessary in total cataracts where the posterior segment of the eye cannot be visualized. Electrophysiologic testing in the form of visual evoked potential is helpful in total cataracts to assess the function of the visual pathways.

DIFFERENTIAL DIAGNOSIS — Other conditions that cause asymmetric red reflex or leukocoria are summarized in the table (table 6). These can generally be distinguished from cataract based upon the ophthalmologic examination findings. The approach is discussed in detail separately. (See "Approach to the child with leukocoria".)

MANAGEMENT

Overview — The management of cataracts in children depends upon the child's age and the potential for interference with visual development. If the cataract is visually significant, management entails removal of the lens and optical/visual rehabilitation, which is critical to preventing amblyopia [27].

Children with good vision (20/50 or better), small opacities (<3 mm), or extra-axial opacities can be managed conservatively [2,28]. Associated refractive error is treated with spectacle or contact lens correction. Occlusion therapy and spectacle correction are often required for children with incomplete unilateral cataracts and/or amblyopia after cataract extraction [29]. (See "Amblyopia in children: Management and outcome", section on 'Patching'.)

Cataract extraction

●Indications – Cataract extraction is indicated for children with bilateral complete cataracts. For children with incomplete cataracts (unilateral or bilateral), indications for surgery include [30]:

•Decreased visual response

•Reduced visual acuity (20/50 or worse)

•Opacity >3 mm in diameter

•Onset of strabismus and/or nystagmus, which indicate a significant disruption in fusion

●Timing – Infants with clinically significant congenital cataracts should undergo surgery as soon as possible, usually at age five to six weeks [2,6]. The visual axis must be cleared by 16 weeks of age to achieve optimal visual outcomes (ie, visual acuity of 20/40 or better) [31,32]. Earlier surgical intervention before the age of five weeks is generally avoided since it is associated with increased risk of glaucoma [33].

To prevent anisometropic amblyopia in infants with bilateral cataracts, the cataracts should be removed within one week of each other (if not removed simultaneously). (See "Amblyopia in children: Classification, screening, and evaluation", section on 'Refractive amblyopia'.)

●Procedure – Pediatric cataract surgery involves removal of the crystalline lens combined with either placement of an intraocular lens (IOL) without disrupting the integrity of the posterior capsule, or anterior vitrectomy/posterior capsulectomy with or without the placement of an IOL.

Children with unilateral cataracts are at increased risk of deprivation amblyopia. Adherence to the postoperative schedule of occlusion therapy is essential to achieving a good visual outcome. Unilateral cataracts often are associated with other ocular pathology, which may further limit visual potential. (See "Amblyopia in children: Management and outcome", section on 'Use of amblyopic eye'.)

Postoperative care — Cataract surgery in children requires a firm commitment on the part of the child's parents/caregivers to become involved in postoperative care [2,34]. The postoperative regimen places a significant burden on the family/caregivers and includes:

●Application of eye drops in the early postoperative period; lack of adherence to this schedule may result in postoperative inflammation, which can have permanent adverse visual sequelae.

●Frequent office visits. (See 'Follow-up' below.)

●Long-term occlusion therapy for amblyopia; inability to comply with ongoing occlusion therapy can result in a suboptimal visual outcome. (See "Amblyopia in children: Management and outcome", section on 'Management'.)

Optical and visual rehabilitation — The crystalline lens serves to focus light on the retina; it also has the ability to accommodate (ie, change focal point from distant to near). In young children (<6 to 9 months) or in patients with small eyes, an aphakic contact lens is used. An aphakic contact lens is a high plus-powered contact lens necessary to provide optical focus in infants who have undergone cataract surgery without implantation of an IOL. When the natural lens is removed in older children, it is usually replaced with an IOL. In addition, bifocal glasses are required for near work because the IOL or contact lens does not accommodate and is typically powered for distance.

After bilateral cataract extraction, aphakic spectacles occasionally may be used to restore focus. However, as techniques for IOL implantation have improved, aphakic spectacles have become less popular [35]. In addition, aphakic spectacles are less cosmetically appealing than standard glasses because the high power of correction requires a thicker-diameter lens.

The age of the patient at the time of surgery is an important factor in determining the best form of optical rehabilitation.

Young infants (<6 months) — For most infants ≤6 months old who undergo cataract surgery, we suggest aphakic contact lenses rather than IOL implantation for optical rehabilitation [2,36]. In this age group, the risk of postoperative complications, such as intraocular inflammation and secondary membrane formation, is lower in children with aphakic contact lenses than in those who undergo primary IOL implantation [36].

In the Infant Aphakia Treatment Study (IATS), a multicenter randomized trial that compared IOL and contact lens correction for monocular aphakia in 114 infants ages one to six months, visual acuity outcomes were similar in both groups at 1 and 10 years of age [36,37]. However, the rate of adverse events was lower in the contact lens group (56 versus 81 percent at five years of age) and fewer patients in the contact lens group required additional intraocular procedures (21 versus 72 percent) [36]. At age 4.5 years, 25 percent of subjects had at least one positive test for stereopsis [38]. Stereopsis was associated with earlier median age at surgery (1.2 versus 2.4 months) and better median visual acuity in the treated eye at age 4.5 years (20/40 versus 20/252) but was not influenced by the surgical procedure.

Another advantage of contact lenses over primary IOL implantation in infants is the ability to change the power of the lens as the refractive power of the eye changes with ocular growth [6]. A large proportion of ocular growth occurs during the first year of life [39-43]. The total refractive power of the aphakic eye decreases from +30.75 at birth to +26.36 at one year, +23.00 at two years, and +21.20 at three years. The provision of a clear retinal image (ie, emmetropia) would require a +30 diopter IOL at birth and a +21 diopter IOL at three years [42]. Infants who are initially rehabilitated with aphakic contact lenses may undergo secondary IOL implantation later in life if contact lenses become more difficult to manage (usually at ≥2 to 3 years of age).

Disadvantages to the use of aphakic contact lenses include the need for daily maintenance, risk of corneal infections in association with contact lens wear, and potential delay of amblyopia therapy [6]. In addition, there are costs to the patient associated with frequent replacement of contact lenses due either to lens loss or the need to change lens power. In a retrospective cost analysis of the IATS study, the overall five-year treatment costs were higher with an IOL compared with aphakic contact lenses (USD $27,090 versus $25,331), but patient costs were more than doubled with contact lenses [44].

Older infants and children — For most children >6 months old, we suggest IOL implantation (pseudophakia) since it offers the best opportunity for visual rehabilitation [45-48]. Advantages of IOL implantation include immediate and full-time optical correction (in contrast to contact lenses that require regular insertion) [6], which greatly aids amblyopia management. However, ocular growth/IOL power and posterior capsule opacification (secondary cataract) may pose management problems. (See 'Postoperative complications' below.)

An IOL also may be particularly beneficial in specific clinical situations:

●Radiation-induced cataracts, which may be associated with ocular surface disease that precludes the use of contact lenses

●Neurobehavioral disorders, in which contact lens insertion can be challenging

●Infants whose families will not be able to comply with contact lens care

Most children with an IOL require glasses postoperatively to optimize optical focus and visual rehabilitation. In addition, older children require a bifocal to provide clear near vision. The use of multifocal IOL in children is investigational.

The previously described IATS study found similar visual acuity outcomes with IOL and contact lens correction; however, the rate of adverse events was increased in the IOL group [36,49]. (See 'Young infants (<6 months)' above.)

POSTOPERATIVE COMPLICATIONS — Complications following surgery may include the following:

●Secondary cataract – Opacification of the posterior capsule of the lens (secondary cataract or visual axis opacification) occurs in virtually 100 percent of young children undergoing cataract surgery. Therefore, it is standard to remove the posterior capsule and perform a primary anterior vitrectomy at the time of cataract extraction in children younger than five to six years of age [48,50-53]. In older children, posterior capsule opacification may occur, but most surgeons leave the capsule intact at the time of cataract extraction because older children can cooperate with laser capsulotomy performed as an office procedure if the need arises [46,48,54].

●Glaucoma – In the Infant Aphakia Treatment Study (IATS; a randomized trial comparing intraocular lens [IOL] and contact lens correction for unilateral aphakia in infants between one and six months of age), 12 percent of 114 subjects developed glaucoma or suspected glaucoma during the first year of follow-up; the risk of glaucoma was increased in infants with persistent fetal vasculature (PFV) and with younger age at the time of surgery [55]. In a follow-up report of the IATS trial cohort, the risk of glaucoma or suspected glaucoma rose to 22 percent glaucoma at 10 years, with similar risk in both groups [36,37]. Another prospective cohort study also reported similar risk of glaucoma in aphakic and IOL-implanted eyes [56]. (See "Overview of glaucoma in infants and children", section on 'Aphakia (due to cataract surgery)'.)

●Strabismus – Strabismus is common among children with unilateral congenital cataract. In the IATS, 70 percent of patients developed strabismus by the 12-month follow-up and 39 percent had undergone strabismus surgery by five years of age [36,57]. The risk of strabismus was not affected by postoperative treatment (IOL versus contact lens).

●Retinal detachment – Retinal detachment is an occasional complication [58,59]. Sudden vision loss or complaints of flashes of light or "floaters" in a child who has undergone cataract surgery deserves immediate evaluation by the ophthalmologist [5]. (See "Retinal detachment".)

●Endophthalmitis – Endophthalmitis (infection within the eye) is a rare but potentially devastating complication, occurring in approximately 0.5 percent of pediatric cataract surgeries [60]. Risk factors for endophthalmitis include nasolacrimal duct obstruction, periorbital eczema, and upper respiratory infection at the time of surgery [6]. Endophthalmitis may occur several days to weeks after surgery [5]. It is characterized by pain, redness, and haziness within the eye from inflammatory cells (picture 8) and is a medical emergency. (See "Bacterial endophthalmitis", section on 'Acute endophthalmitis after cataract surgery'.)

Intracameral antibiotics are often administered to reduce the risk of postoperative endophthalmitis. Though there are limited data on this practice in pediatric cataract surgery, its efficacy is supported by randomized trials in adults undergoing cataract surgery [61,62]. (See "Cataract in adults", section on 'Preventing endophthalmitis'.)

PROGNOSIS — The visual prognosis for pediatric cataracts has improved significantly over the years. Visual acuities of 20/20 to 20/40 may be achieved if cataracts are diagnosed and treated early [54,63,64].

Visual outcome depends upon age of onset, whether the cataract is unilateral or bilateral, cataract morphology, pre- and coexisting ocular abnormalities, postoperative course and complications, and adherence to amblyopia treatment [2]. Visual outcomes are generally better in children with bilateral cataracts compared with unilateral cataracts. In the Infant Aphakia Treatment Study (IATS) which evaluated patients with unilateral cataracts only, the median visual acuity at 4.5 years was 20/159 [36].

Additional factors associated with a poor visual outcome include [2,20,65]:

●Nystagmus at presentation

●Strabismus at presentation or in the follow-up period

FOLLOW-UP — Regular ophthalmology follow-up is crucial for a successful outcome in children who have undergone cataract surgery (with or without intraocular lens [IOL] implantation) [34]. Most children will have frequent changes in refraction, requiring spectacle prescription change, and need ongoing amblyopia therapy to optimize visual outcome. Any ocular redness or reported changes in vision should be reported to the ophthalmologist immediately.

Patients with poor visual outcome may benefit from local, state, or federal services for the visually handicapped and/or blind.

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topics (see "Patient education: Cataracts (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Classification and etiology – Pediatric cataracts are usually classified according to their morphologic appearance (table 1). Approximately one-third of cataracts in children are inherited, one-third are associated with other disease (table 2), and one-third are idiopathic or sporadic. Acquired cataracts may be caused by ocular trauma, glucocorticoids, and exposure to radiation. (See 'Classification' above and 'Etiology' above.)

●Presentation – Infants and children with cataracts may present with an asymmetric red reflex (figure 3), leukocoria, photophobia, strabismus, nystagmus, poor vision, and/or abnormal visual behavior (table 3). (See 'Clinical features' above and 'Examination' above and "Vision screening and assessment in infants and children".)

●Evaluation – The evaluation of an infant or child with a cataract focuses on determining the etiology of the cataract, assessing the child's vision, characterizing the cataract morphology, and identifying coexisting eye disease. Identification of associated systemic disease (table 2) may have important management implications (eg, galactosemia). In many cases, the underlying etiology can be determined by the history, physical examination, and ophthalmologic examination. If the cause remains uncertain, additional evaluation may be warranted. (See 'Evaluation' above and 'Etiologic evaluation' above.)

●Referral indications – Patients with any of the following should be referred to an ophthalmologist for further evaluation (see 'Referral indications' above):

•Clinical findings suggestive of cataract (eg, leukocoria, asymmetric red reflex (figure 3), decreased visual acuity, strabismus)

•Family history of childhood-onset cataract

•Long-term systemic glucocorticoid use

•History of cranial or total-body irradiation

•Systemic disorder associated with cataracts (table 2)

●Management – The management of cataracts depends upon the age at presentation and the potential for interference with visual development. If the cataract is visually significant, management involves removal of the lens and optical/visual rehabilitation, which is critical to preventing amblyopia (see 'Management' above):

•For infants with bilateral complete cataracts, we recommend cataract extraction (Grade 1B). Surgery should take place ideally at age five to six weeks. The two eyes should be operated on within one week of each other. (See 'Cataract extraction' above.)

•For children with incomplete cataracts (unilateral or bilateral), we suggest surgery if any of the following features are present (Grade 2C) (see 'Cataract extraction' above):

-Decreased visual response

-Reduced visual acuity (20/50 level or worse)

-Opacity >3 mm in diameter

-Onset of strabismus and/or nystagmus, which indicate disruption in fusion

•When the natural lens is removed, it must be replaced with an intraocular lens (IOL) or an aphakic contact lens (see 'Optical and visual rehabilitation' above):

-For most infants ≤6 months old, we suggest aphakic contact lenses rather than IOL (Grade 2B). Aphakic contact lenses are associated with a lower risk of complications in young infants, and they permit changing the power of the lens as the refractive power of the eye changes with ocular growth. (See 'Young infants (<6 months)' above.)

-For most children >6 months old, we suggest IOL implantation (Grade 2C). The risk of complications is lower in this age group, and IOL implantation offers the best opportunity for visual rehabilitation. In addition, bifocal glasses are required for near work. (See 'Older infants and children' above.)

•Postoperative complications may include opacification of the posterior capsule (if posterior capsulectomy/anterior vitrectomy is not performed at the time of cataract extraction), glaucoma, retinal detachment, and endophthalmitis. Children who develop sudden vision loss, ocular pain, or ocular redness any time after cataract surgery should be evaluated promptly by an ophthalmologist. (See 'Postoperative complications' above.)

●Follow-up – Regular ophthalmology follow-up is crucial for successful outcomes in children who have undergone cataract surgery (with or without IOL implantation). (See 'Follow-up' above.)