Vision Disturbances
An important role of the primary care physiciancaring for children is to screen for visual problems, so that lossof vision can be prevented or treated when possible. The precisediagnosis is usually made by an ophthalmologist. This chapter discussesthe more common vision defects.
Principal Causes of Vision Disturbances
- Oculardisorders
- Congenitalanomalies
- Globe
- Lens
- Cornea
- Iris
- Vitreous
- Refractive errors
- Myopia
- Hyperopia
- Astigmatism
- Anisometropia
- Strabismus
- Amblyopia
- Trauma
- Infection
- Cataracts
- Glaucoma
- Uveitis
- Anterior uveitis
- Posterior uveitis
- Retinal disorders
- Retinopathyof prematurity
- Retinitis pigmentosa and other retinaldystrophies
- Retinal detachment
- Albinism
- Neoplasm
- Metabolic disorders
- Neurologic disorders
- Lesionsof optic nerve or chiasm
- Optic nerve aplasia
- Optic nerve hypoplasia
- Optic atrophy
- Optic neuritis
- Lesions of optic pathways
- Lesions of visual cortex
Clinical Features and Diagnosis
Ocular Disorders
Congenital Anomalies
Globe
A small eye may be normal histologicallyor may be malformed and associated with coloboma or persistenceof fetal vasculature. Coloboma, a notch or gap of any ocular structurelocated in fundus or iris, may cause impaired vision if macula,optic nerve, or retina is involved. Persistence of fetal vasculatureis discussed in section Vitreous.
Lens
Absenceof lens is called congenital aphakia, which is rare.Small or dislocated lens may causesevere myopia.See section on Cataracts. Cornea
Small orlarge corneas may be associated with ocular malformations, otherpathologic lesions, and refractive errors.Measurement of corneal size is madein the horizontal direction. Small cornea is <10 mm in newbornsand <11 mm in older children, whereas large cornea is >12mm in newborns and >13 mm after age 2. Iris
Aniridia(absence of iris tissue) is autosomal-dominant disorder that maybe associated with cataracts, nystagmus, optic nerve hypoplasia,and glaucoma.WAGR syndrome (Wilms tumor–aniridia–genitourinaryanomalies–mental retardation) is caused by chromosomaldeletion at 11p13.Rieger syndrome causes ectopic pupil(corectopia) or multiple pupils (polycoria). Also may be associatedwith glaucoma. Vitreous
Persistenceof fetal vasculature was formerly called persistent hyperplasticprimary vitreous.Results in formation of dense vitreousband that can extend from posterior lens to optic disc. Usuallyunilateral and is characterized by small eye that often has whitepupillary reflex.Associated abnormalities include cataracts,glaucoma, and retinal detachment. Refractive Errors
Disturbancesin specific optical properties of eye.Primary refractive errors are myopia,hyperopia, and astigmatism. Anisometropia occurs when there areunequal refractive errors.Normal vision can usually be restoredby proper lens correction if no other problem exists. Myopia
Myopic children have normal near vision butblurry distance vision. This disorder is often first noticed inschool-aged children, when they complain that they cannot clearlysee writing on blackboard in school.
Hyperopia
Children with hyperopia have more difficultywith near vision and must accommodate for clearer focus. They areprone to develop accommodative esotropia.
Astigmatism
Resultsfrom small differences in radius of curvature of cornea or lens.Parallel rays of light enter eye and focus at different points ratherthan at 1 point, so retinal image is blurred.Can occur as isolated finding or withmyopia or hyperopia.Glasses or contact lenses can compensatefor astigmatism. Anisometropia
May cause difficulty in using eyes togetherand may lead to strabismus or amblyopia.
Strabismus
Strabismus(crossed eyes or squint) is misalignment of eyes and occurs in about3% of pediatric population. Can be normal during maculardevelopment in first 4 mos of life, but its persistence after thisage is abnormal.Without proper treatment during infancyand early childhood, strabismus can lead to amblyopia with lossof vision in nonfixing eye. Small deviation of eye turning in (esotropia)or out (exotropia) may produce severe loss of vision.2 diagnostic tests used to detect strabismusare corneal light reflex test in infants and more accurate covertest in preschool- and school-aged children.When child looks straight ahead atsmall flashlight, corneal light reflex is normally in middle ofeach pupil. If reflex is off center in 1 pupil compared with theother, strabismus exists.Using cover test in child with strabismus,when normal eye is covered, uncovered eye moves to fix on light.When normal eye is uncovered, nonfixing eye shifts back to its abnormalposition. Because most children with strabismusare asymptomatic, it is important to test for strabismus on eachwell-child visit. When physician diagnoses strabismus, ophthalmologicconsultation is mandatory. Amblyopia
Is a decreasein vision without detectable lesions of eye. Strabismus and anisometropiaare most common causes.To detect amblyopia when it is stillreversible, vision testing must be performed well before schoolage. Optimal time is 3–4 yrs of age. Before this age, testingof visual acuity is subjective, although good fixation and followingwithout nystagmus or strabismus indicate good visual function. Detectionof amblyopia before 4 yrs of age offers best chance of successfultreatment, but older children may respond well to treatment. Trauma
Cornealabrasion, foreign body, contusion with hyphema formation, lacerationof globe, perforation of eye, and burns may cause defective vision.History and exam of eye including slit-lampexam are diagnostic. Visual acuity should always be measured whentrauma to eye has occurred. Infection
N. gonorrhoeae, herpes simplex virus, cytomegalovirus,T. gondii, and Toxocara species can cause serious eye infections,resulting in loss of vision. These infections are discussed in Chap. 36, Jaundice, and Chap. 54, Red Eye.
Cataracts
Are opacitiesof the crystalline lens of the eye that may interfere with the development andmaintenance of normal vision.May present with leukocoria, nystagmus,strabismus, photophobia, visual inattentiveness, or irregular orabsent red reflex. Older children are aware of decreased visualacuity in affected eye.Although cataracts can often be seenby focal illumination with penlight, direct ophthalmoscopy confirmstheir presence.Table74.1 lists common causes of cataracts in infants andchildren.Children of any age who have a suspectedcataract should be referred for ophthalmologic consultation. Table 74.1. Common Causes of Cataracts in Infants and Children
| Idiopathic (most common) |
| Genetic (autosomal dominant, autosomal recessive, X-linked) |
| Congenital infection |
| Rubella virus |
| Cytomegalovirus |
| Herpes simplex virus |
| Toxoplasmosis |
| Galactosemia |
| Galactose-1-phosphate uridyltransferase deficiency |
| Galactokinase deficiency (only sign is congenitalcataract, which occurs in all cases) |
| Dysmorphic syndromes |
| Association with congenital ocular abnormalities |
| Aniridia |
| Coloboma |
| Persistence of the fetal vasculature |
| Persistent pupillary membrane |
| Association with acquired ocular abnormalities |
| Ocular trauma |
| Glaucoma |
| Retinopathy of prematurity |
| Uveitis |
| Retinoblastoma |
| Diabetes mellitus |
| Juvenile rheumatoid arthritis |
| Chronic corticosteroid therapy |
Glaucoma
Is a conditionof the eye characterized by increased intraocular pressure.Primary glaucoma is due to isolatedabnormality of aqueous drainage system of eye and is often geneticin origin, whereas secondary glaucoma occurs because of ocular disease,systemic disease, drugs, or injury (Nelson, 1998).In young children, epiphora (tearing),photophobia (sensitivity to light), and blepharospasm (squeezingof eyelids) may indicate presence of glaucoma. Eyes also may belarge, sclerae injected, and corneas hazy. Older children usuallypresent with eye pain related to acute glaucoma or loss of visiondue to chronic glaucoma.Diagnosis is confirmed by ophthalmologicexam, including measurement of intraocular pressure. Uveitis
Anterior Uveitis
Childrenwith anterior uveitis may present with red eye, photophobia, pain,or decreased vision. Cells and flare are seen in anterior chamber.Causes include juvenile rheumatoidarthritis, herpes simplex virus, varicella-zoster virus, sarcoidosis,syphilis, and idiopathic. Posterior Uveitis
Decreasedvision is usually presenting symptom of posterior uveitis. Olderchildren may complain of blurred vision or seeing floaters. Inflammatorycells are seen in vitreous.Most common causes are toxoplasmosisand toxocariasis. Retinal Disorders
Retinopathy of Prematurity
This retinalvascular disorder primarily affects premature infants. The lowerthe birth weight, the higher the risk.Signs of retinopathy usually appear32–34 wks after conception, and primary effects begin inmore immature temporal retinal vessels. In severe cases, retinaldetachment and impaired vision occur.A classification has been developedfor evaluation of this disorder (Nelson, 1998). Retinitis Pigmentosa and Other Retinal Dystrophies
Retinitispigmentosa is characterized by night blindness, contracted visualfields, and pigment deposition in retina.Genetic transmission may be autosomal-recessive,autosomal-dominant, or X-linked recessive.Often first appears in adolescence.Many systemic disorders may be associatedwith retinitis pigmentosa (Nelson, 1998).Other retinal dystrophies may causepoor central vision and decreased color vision, and may be congenitalor acquired. Nystagmus may be presenting sign in congenital cases. Retinal Detachment
Disorder in which fluid separates outer layerof retina from underlying retinal pigment epithelial layer. Mostcommon causes in pediatric population are retinopathy of prematurityand blunt trauma.
Albinism
Ocular form of albinism involves only theeyes, whereas oculocutaneous form also involves the skin. Eye findingsare similar in both forms and consist of diminished visual acuity,nystagmus, photophobia, foveal hypoplasia, and decrease in pigmentationof retinal pigment epithelium and choroid.
Neoplasm
Retinoblastomais most common primary intraocular tumor of childhood and commonlypresents with leukocoria or strabismus. Individual tumors appearas white retinal masses.Disease is transmitted as autosomal-dominanttrait or may occur sporadically.Gene locus has been mapped to chromosome13q14.1-14.2.Visual loss or blurred vision alsomay occur with intraocular leukemia. Metabolic Disorders
Some metabolicdisorders may cause accumulation of substances in the eye that can resultin visual loss and blindness.Cherry-red spot (red macula surroundedby accumulation of substances that produce whitish appearance) maybe seen with GM-1 gangliosidosis, Tay-Sachs disease, Sandhoff disease,and Niemann-Pick disease. See Chap.13, Developmental Delay, for discussion of thesedisorders. Neurologic Disorders
Lesions of Optic Nerve or Chiasm
Optic Nerve Aplasia
Is the complete absence of optic nerve, opticdisc, ganglion cell and nerve fiber layers, and retinal vasculature.
Optic Nerve Hypoplasia
Decreasein number of axons within optic nerve occurs with hypoplasia.Pupil is sluggish in response to light.Optic disc is small and pale gray in color. Nystagmus and decreasedvision usually occur.May be associated with septooptic dysplasia,which is also characterized by absence of septum pellucidum andsometimes growth hormone deficiency. Optic Atrophy
Is the permanentloss of function of some or all of optic nerve.Optic disc is pale, and visual acuityis decreased.Etiology includesGenetic disorders (autosomal-dominant,-recessive, or X-linked inheritance)Acquired disorders (perinatal asphyxia,trauma, hydrocephalus)Inflammatory disorders (optic neuritis)Tumors (optic nerve glioma, meningioma,craniopharyngioma, pituitary adenoma)Toxin/nutritional disorders(lead intoxication; vitamin B12, folate, andthiamine deficiencies)Metabolic disorders (mucopolysaccharidoses,Tay-Sachs disease, globoid cell leukodystrophy, metachromatic leukodystrophy) Optic Neuritis
Optic neuritis(inflammation of optic nerve head or disc) can be unilateral orbilateral.Common findings are pain on eye movement,decreased pupillary response to light, and loss of central vision.Causes include virus infections (measles,mumps, varicella, influenza, infectious mononucleosis), orbitalcellulitis/abscess, Guillain-Barré syndrome, andmultiple sclerosis. Lesions of Optic Pathways
Any lesion that affects optic pathways behindoptic chiasm produces homonymous hemianopsia or quadrant anopsia.Common causes include intracerebral tumor, intracranial hemorrhage,and brain abscess.
Lesions of Visual Cortex
Causes ofcortical blindness include cerebral malformations affecting visualcortex, hypoxic-ischemic encephalopathy, bacterial meningitis, viralencephalitis, brain tumor, intracranial hemorrhage, epidural orsubdural hematoma, cerebral emboli, occipital lobe abscess, andhead trauma.Cortical visual loss should be suspectedwhen child sees poorly, but pupils are normally reactive and opticnerve head is of normal size and color.Visual evoked potentials are usefulin confirming diagnosis of cortical blindness. Diagnostic Approach
Goal ofprimary care physician is to detect any vision disturbance and torefer child to ophthalmologist for further evaluation and treatment.Normal visual acuity is estimated tobe 20/400 at birth. By 1 yr of age, acuity improves to 20/30as determined by sophisticated electrophysiologic and psychophysiologictechniques. By 2–3 yrs of age, some children have objectivevisual acuity of 20/40–20/50. 4-yr-oldscan usually read 20/30–20/40, whereas5-yr-olds should be reading 20/20–20/30.Any child with 2 or more lines of differencebetween the eyes should be suspected of having amblyopia. Neonates
Direct ophthalmoscope should be used to checkred reflex, which is reflection of light from retina. Color andintensity of reflex should be same in each eye. Mild eye misalignmentcan be normal finding at this age and usually disappears by 2 mosof age.
Infants
By 2–3mos, eyes of infants should be straight and they should be ableto follow large objects. At each visit red reflex should alwaysbe checked. Any difference in this reflex can indicate several eyeproblems, and ophthalmologic referral is mandatory.Corneal light reflex test can be usedto distinguish strabismus from pseudostrabismus. Reflection of lightsource (e.g., penlight or direct ophthalmoscope) should be in sameposition in each pupil. Normally, this reflection is just nasalof center of each pupil. If there is difference in its positionbetween 2 pupils, strabismus is present and referral is necessary. Preverbal Children
Exam forstrabismus is important at each well-child visit. In most instancesstrabismus occurs before 3 yrs of age.Esotropia (eye turning in) usuallyoccurs when child is looking at something near (e.g., picture ortoy), whereas exotropia (eye turning out) usually occurs when childis looking at object >10 ft away.Corneal light reflex and cover testscan be used to screen for these problems (see section on Strabismus). If ocularmisalignment is found, child should be referred to ophthalmologistfor further evaluation. Verbal Children
For children≥3 yrs of age, vision can be screened by several tests usingLea symbols, Tumbling E, the letters "HOTV", Snellennumbers or letters, and Allen recognition figures.Important to determine visual acuityof each eye and any difference in vision between the eyes, evenif it is just 1 line on chart.Child with vision of 20/40in both eyes or worse or difference of 2 lines in vision between theeyes should be referred for ophthalmologic evaluation. References
- American Academy of Pediatrics, Committeeon Practice and Ambulatory Medicine, Section on Ophthalmology. Eyeexamination and vision screening in infants, children, and youngadults. Pediatrics 1996;98:153–158.
- Calhoun JH. Cataracts in infancy. Pediatr Rev 1988;9:227–233.
- Calhoun JH. Eye examinations in infants and children.Pediatr Rev 1997;18:28–31.
- Catalano RA, Nelson LB. Pediatric ophthalmology: atext atlas. Norwalk, CT: Appleton & Lange, 1994.
- Hartmann EE, et al., on behalf of the Maternal andChild Health Bureau and the National Eye Institute Task Force onVision Screening in the Preschool Child. Preschool vision screening:summary of a task force report. Pediatrics 2000;106:1105–1112.
- Nelson LB, ed. Harley's pediatric ophthalmology,4th ed. Philadelphia: WB Saunders, 1998.
- Online Mendelian Inheritance in Man (OMIM). McKusick-NathansInstitute for Genetic Medicine, Johns Hopkins University (Baltimore,MD) and National Center for Biotechnology Information, NationalLibrary of Medicine (Bethesda, MD), 2000. World Wide Web URL: http://www.ncbi.nlm.nih.gov/omim.
- Rudolph AM, ed. Rudolph's pediatrics, 20thed. Stamford, CT: Appleton & Lange, 1996.
- Taylor D, ed. Pediatric ophthalmology, 2nd ed. Oxford:Blackwell Science, 1997.
- Tongue AC. Refractive errors in children. Pediatr ClinNorth Am 1987;34:1425–1437.
- Traboulsi EI, ed. Genetic diseases of the eye. NewYork: Oxford University Press, 1998.
- Wright KW. Pediatric ophthalmology for pediatricians.Baltimore: Williams & Wilkins, 1999.
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Book Source Details
- Book Title: The Diagnostic Approach to Symptoms and Signs in Pediatrics
- Author(s): Paul S. Bellet
- Year of Publication: 2006
- Copyright Details: The Diagnostic Approach to Symptoms and Signs in Pediatrics, Copyright © 2006 Lippincott Williams & Wilkins.
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Copyright Details: The Diagnostic Approach to Symptoms and Signs in Pediatrics, Copyright © 2008 Williams & Wilkins.
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