Pediatric Cataract (for ABO Credit)
by Benjamin Betines, Licensed Optician, NJ, ABOC
Release Date: November 1, 2017
Expiration Date: October 23, 2022
Blindness in children is a grave concern to societies throughout the world. Although there have been great advances in the field of ophthalmology in the recent past, visual impairment and blindness in children are primarily due to preventable causes. There are over 1.4 million children in the world who are blind and 17.5 million throughout the world with vision so low that their daily living activities are severely hampered. Consequently, the effect on vision, the course of treatment and prognosis can vary greatly. Cataract problems are the greatest source of preventable blindness cases. The latest World Health Organization estimates state that there are more than 200,000 cases worldwide of preventable blindness (WHO, 2014). What should you know about pediatric cataracts?
Upon completion of this program, the participant should be able to:
- Understand the nature and types of cataracts.
- Learn the effects of untreated cataracts in children.
- Know the opportunities for treatment and possible alternatives.
Benjamin Betines, Licensed Optician, NJ, ABOC
This course is approved for one (1) hour of CE credit by the American Board of Opticianry (ABO). 1 hour, General knowledge Course SWJH005
Blindness in children is a grave concern to societies throughout the world. Although there have been great advances in the field of ophthalmology recently, visual impairment and blindness in children are primarily due to preventable causes. There are over 1.4 million children in the world who are blind and 17.5 million throughout the world with vision so low that their daily living activities are severely hampered (Ram, Agarwal, Kumar & Gupta, 2014).
Consequently, the effect on vision, the course of treatment and prognosis can vary greatly. Cataract problems are the greatest source of preventable blindness cases. The latest World Health Organization estimates state that there are more than 200,000 cases worldwide of preventable blindness (World Health Organization, 2014).
India and China account for more than 20 percent of the visually impaired population (Ram, Agarwal, Kumar, and Gupta, 2014). The reported percentages from Africa and the Eastern Mediterranean are 15%, although these figures are likely underestimating the actual numbers because many cases of children with multiple disabilities may go unreported. Pediatric cataracts pose a great economic burden and cause years of productive life to be lost due to untreated cases (World Health Organization, 2014). Therefore, it is vital that children are properly diagnosed and receive prompt cataract treatment to allow for proper development of vision.
Definition of Cataract
A cataract is an opaque condition of the lens of the eye. It is positioned behind the pupil and is readily distinguished from an opacity of the cornea. A cataract may affect the lens alone (lenticular), or the front or back of the capsule of the lens (capsular), or both lens and capsule (capsule lenticular). A cataract is painless and generally unaccompanied by inflammation. It develops at a slow rate and interferes with vision. When left untreated, a cataract causes blindness by obstructing the passage of light. However, the patient can still distinguish light from darkness. Cataracts can form in both eyes, but don't always develop at the same time and rate of progression. (Shiels & Hejtmancik,2013).
Types of Cataract
Cataracts can be nuclear, cortical or posterior capsular, depending on the location. A nuclear cataract forms in the middle of the lens and causes the nucleus, in the center, to become yellow or brown. Cortical cataract is wedge-shaped and forms around the edges of the nucleus. A posterior capsular cataract forms faster than the other two types and affects the back of the lens (Vasavada & Nihalani, 2009).
A cataract can develop at any age. However, the most common form usually occurs in persons over 50 years old (World Health Organization, 2014). The age-related cataract begins with dark streaks extending from the outer boundary toward the middle of the lens, or as spots in any portion. Within a period of time, the cataract makes the entire lens opaque. Because the fluid of the lens is absorbed, the lens becomes separated from its capsule and becomes mature for the removal operation. If the cataract is not removed, the lens significantly deteriorates and liquefies. The capsule becomes thickened and opaque, and the results of the operation become less satisfactory (Shiels & Hejtmancik, 2013).
Periodic evaluations are required to detect any other post-operative complications such as secondary cataract, inflammation, glaucoma, or retinal detachment. A pediatric patient who has recently undergone cataract surgery will require frequent medical and ophthalmologic follow ups of visual development. The patient may need changes in glasses or contact lenses as the eye matures.
Cataracts may also occur in people with other health problems, such as high blood pressure or diabetes. A cataract may develop after a traumatic eye injury, many years later. Cataracts are also linked to steroid use and can develop after exposure to some types of radiation. Over half of people in the United States have or had cataracts and have undergone cataract surgery by the time they're 80 years old according to the National Eye Institute (2009).
Today, the only method of alleviating advanced cases of cataract involving severe vision loss is the extraction of the lens. In many cases, good vision is recovered when the patient is prescribed special eyeglasses or contact lenses or by an ophthalmologist implanting an artificial lens within the affected eye. (Goggin, Moore & Esterman, 2011).
Diagnosis of Pediatric Cataract
A congenital cataract is present at birth or forms during a baby's first year. This type of cataract is less common than age-related cataracts and can occur in approximately one in every 10,000 infants. A congenital cataract may be caused by inherited disorders or congenital diseases, such as rubella. In many cases of congenital cataract, there is a family history. A prenatal and pregnancy history should be taken (Reddy, Francis, Berry, Bhattacharya & Moore, 2009). Congenital cataracts can develop if the mother has an infection or uses drugs or alcohol while pregnant. It is estimated that congenital cataract is responsible for 5% to 20% of blindness in children worldwide. Incidence varies from country to country (Pascolini & Mariotti, 2012). According to the World Health Organization (2014), the prevalence of infantile cataracts in the U.S. showed a rate of 3-4 visually significant cataracts per 10,000 live births. The U.K. showed 3.18 per 10,000. These numbers underestimate the total number since they do not take into consideration the visually insignificant cataract (World Health Organization).
A congenital cataract may be unilateral or bilateral. It can vary widely in size, morphology and degree of opacification, ranging from a small white dot on the anterior capsule to total opacification of the lens. The greatest complication of congenital cataracts can be irreversible visual defects. During the time sensitive period of visual development, if the visual axis becomes blocked by lens opacity, irreversible visual defects such as amblyopia and permanent nystagmus may result. The first two months in the life of an infant are the most important for visual development. Amblyopia ensuing from visual deprivation after the age of 2 to 3 months will be reversible to some extent since visual development will continue until the child is a minimum of 7 years of age.
An infant with mild cataracts may not show any symptoms delaying cataract diagnosis for years. Parents have cause for concern when they notice the child's lack of reaction to light, strabismus and failure to notice toys or an apparent delay in development. A juvenile cataract can be easily visible in the undilated state and apparent to parents and a pediatrician, or may be more subtle and require dilation and examination with a slit lamp. Not all cataracts need to be removed unless the cataract interferes with the child's vision. (Pascolini & Mariotti, 2012).
Juvenile cataracts may be hereditary. This type of cataract does not always have symptoms and should be removed only if it interferes with the child's vision. The lens is soft and white in both congenital and juvenile cataracts. Unilateral cataract carries a less favorable prognosis than bilateral cataracts and even a minimal opacity can create significant amblyopia (Plager, Lynn, Buckley, Wilson & Lambert, 2011).
A child with a unilateral cataract is also at greater risk for anisometropia, which can further complications. In addition to clearing the visual axis by appropriate surgical technique, accurate optical correction using aphakic glasses, contact lenses, or an intraocular lens implant becomes imperative for good visual development. This requires an ongoing medical care commitment from both the ophthalmologist and the family of the child. It becomes imperative that prompt treatment of visually significant cataracts is obtained to allow proper development of vision (Plager, Lynn, Buckley, Wilson & Lambert, 2011).
Pediatric cataracts can also develop from a traumatic event resulting from a perforating wound of the capsule or from a concussion of the lens. The entire lens may become opaque and inflammation of other portions of the eye may follow. Close monitoring by a physician is necessary (Sukhija & Ram, 2012).
Causes of Pediatric Cataracts
The causes of pediatric cataracts are the source of much current research. A distinction between unilateral and bilateral cataract is a consideration as well as systemic associations, including metabolic disorders such as galactosemia, Wilson disease, hypocalcemia and diabetes (Reddy, Francis, Berry, Bhattacharya & Moore, 2009). Cataracts can also be part of a number of syndromes, the most common being trisomy which is a chromosomal abnormality. Congenital cataracts can also occur if a pregnant woman develops an infection such as chicken pox, cytomegalovirus, poliomyelitis, syphilis, herpes zoster, herpes simplex, influenza, measles or rubella (the most common cause), Epstein-Barr virus and toxoplasmosis (Reddy, Francis, Berry, Bhattacharya & Moore, 2009). Most unilateral cataracts are not inherited or associated with a disease. They are usually the result of abnormal organ development during embryonic growth and may be associated with persistent fetal vasculature (PFV), posterior lenticonus, or lentiglobus (Douglas, Rafferty, Hodgins, Nagra, Foulds, Morgan &Temple, 2010).
While certain causes of cataracts in children are well-documented and researched, such as perinatal and intrauterine infections, many cases may go without a definite diagnosis. Childhood cataract has been associated with genetic mutations, premature birth and enzyme defects. While trauma such as a blow to the eye is the main cause in 40 percent of cases of cataracts in older children, drug induced cataracts due to steroids are also common. Genetic defects can be associated with an abnormal lenticular shape that will need surgical management. (Deng, & Yuan, 2014).
Pediatric Cataract Evaluation and Management
What is needed in order to identify children at risk is a thorough visual acuity assessment using specialized charts, pupillary reaction, strabismus and ocular motility testing. Slit-lamp biomicroscopy is the best method to evaluate lenticular opacities and study the morphology of cataracts (Vasavada, Praveen, Vasavada, Shah & Trivedi, 2012). An intraocular pressure measurement should be taken to rule out congenital glaucoma. A fundus examination should be performed by indirect ophthalmoscopy after pupillary dilation to rule out posterior segment pathology. In addition, a detailed evaluation of family history should be done (Vasavada, Praveen, Vasavada, Shah & Trivedi, 2012).
A new tool that can help to diagnose and identify cataracts is the HD Analyzer. It is a diagnostic system that enables an objective analysis of the optical quality within the eye. The HD Analyzer objectively measures light scatter, which is not measurable using traditional aberrometry techniques. The modern technique of phaco aspiration with posterior chamber intraocular lens implantation in the capsular bag is the preferred technique to manage pediatric cataracts. This has replaced older techniques of lensectomy and extra capsular cataract surgery. An ultrasound scan can rule out posterior segment pathology in children with dense cataracts (Vasavada & Nihalani, 2009).
A child's eye is different from an adult's eye. Unlike cataracts in adults, there is an immediate need to manage childhood cataracts, especially those that are unilateral. There is generally a poor prognosis associated with delayed surgery. Various factors contribute to surgical difficulty. Therefore, surgeries may be limited to dedicated, specialized centers. The key to successful pediatric cataract surgery is the post-operative management. Post-operative care in children is highly specialized since pediatric eyes are susceptible to high levels of inflammation. High dose steroids may be required as well as antibiotic therapy (Ram, Gupta, Sukhija, Chaudhary, Verma, & Kumar, 2011).
There is increasing evidence of genetic variances that can be responsible for cataract development. Therefore, genetic counseling is probably going to play an important role in patient management in the future. Identification of mutations responsible for early cataract development can help formulate guidelines regarding genetic counseling (Kumar, Kaur & Dada, 2013). When researching inherited forms of congenital cataracts, it has been found that abnormalities can occur in the formation of proteins that are essential in maintaining transparency of the eye's natural lens. A significant body of research indicates that nutritional intervention may offer a way to diminish the risk of cataracts in children. Much of the early research looking at the role of diet in cataract formation focused on antioxidants. However, research has now been expanded to include macronutrients such as fatty acids, carbohydrates, vitamin C and other nutrients important for eye health (Douglas, Rafferty, Hodgins, Nagra, Foulds, Morgan & Temple, 2010).
There have been tremendous changes via technology in the field of ophthalmology. The future of pediatric cataract identification, medical care and management hold promise. New and innovative surgical approaches and more effective drugs to control inflammation now make it possible to identify cataracts very early and intervene before damage is done. Benchmarks for postoperative outcomes after pediatric cataract surgery have risen. Presently, the ophthalmic focus is on achieving the highest grades of binocularity (Vasavada & Nihalani, 2009).
However, the task of managing pediatric cataracts remains difficult since there are potential complications at every stage of identification and treatment. According to the World Health Organization (2014), India has 400,000 blind children living in poverty, and mortality rates are high. They estimate that up to 60 percent of children die within one year of going blind. Sinha (2013) states that less than 10 percent of these visually impaired children receive any education and blind girls are confined to their homes. In nearly 40 percent of the identified cases, blindness was treatable or preventable. These dire circumstances mean that a blind child from a poor rural family may live a tragic, short life. Sinha (2013) emphatically states that when children live in remote places, it is imperative for ophthalmologists to identify those children with vision problems. A delay in the diagnosis of pediatric cataracts can compound the problem, since delayed treatment is related to permanent visual disorders. Even after adequate specialized care, vision disorders and severe amblyopia can occur. Identification of cases and prompt referrals are areas that need to be strengthened if ophthalmologists want to remediate the problem (Sinha, 2013).
Preventative measures for pediatric cataract are critical because the availability of pediatric identification and surgery in much of the world is insufficient. Research indicates that nutritional intervention may offer a way to diminish the risk of cataract with a diet that is enhanced by vitamin C, lutein, B vitamins, omega-3 fatty acids, multivitamins and carbohydrates (Douglas, Rafferty, Hodgins, Nagra, Foulds, Morgan & Temple, 2010).
It becomes apparent that rates of pediatric blindness due to cataracts vary widely among countries because of disparities in financial resources, the remote locations of children, genetic factors and the availability of ophthalmologists. The medical challenge for the future is to increase the world's perception that excellent vision needs to be a priority for all people.