1. Vision problems NUR 584 Health Promotion and Clinical Prevention
Pediatric Special Topic
Vision problems

2. Objectives Introduction Natural History Primary Prevention
Secondary Prevention
Tertiary Prevention
Common Errors
Emerging Trends
Proper vision screening and eye examination are critical for the early detection of conditions that can lead to poor school performance or blindness in children. Vision problems in children occur in as many as 5% to 10 % of preschool children and 20 – 30% of school age children. Primary care providers must be aware of the age-appropriate evaluations that will indentify infants and children who need early referral to an ophthalmologist for diagnosis and treatment of visual problems to prevent permanent, irreversible blindness. Three major vision-threatening problems that must be recognize include amblyopia, stabismus, and cataracts. Refractive errors should also be recognized.

3. Introduction Amblyopia
Loss of vision due to inadequate visual stimulation of the brain during cortical visual development.
Causes
Strabismus – Improper Alignment
Hyperopia – Far Sightedness
Astigmatism – Unfocused images on the retina due to unequal curvative of the refractive surface
Cataract – Opacity of the lens
Eye Lid Hemangioma
Blepharoptosis – Dropping eye lid
Amblyopia is one of the most common physical problems in children, occurs in approximately 2% of the general population. Strabismus is the most common cause of amblyopia. Amblyopia results when the brain ignores the incoming images from the crossed eye to prevent blurry vision.
ESO – medial deviation.
EXO – lateral deviation
Esodeviation (medial deviation – most common type of strabismus)
-phoria – tendency of the eye to drift from the visual axis during fatigue
Vs. – tropia – eye drift from the visual axis that is always present
Cover/Uncover test for Heterotropias.

4. Strabismus Improper alignment. Infantile Strabismus
Appears before 6 months of age and usually associated with family history. Referral if persists beyond 6 months of age.
Constant fixation more likely to result in amblyopia of the eye that is turned inward.
May require surgical correction by age 2 if does not resolve.
Accomodative esotropia
Due to hyperopia (farsightedness).
May be intermittent or persistent, usually hereditary
Appears between infancy and 4 years of age.
Most noted when child is tired, ill, or looking into the distance.
Late-onset, constant exotropia is more worrisome – may indicate ocular or central nervous system disease
There may be alternative fixation, in which either the left eye or, at other times, the right eye turns medially. With this type of strabismus there is less risk of amblyopia, since the deviation alternates, allowing each eye to develop vision. Constant fixation is more likely to result in amblyopia or the eye that is turned inward.

5. Cataracts Opacity of the lens May be congenital or acquired.
1/4 are familial (autosomal dominant); 1/3 are related to maternal infection during pregnancy (rubella). Remainder are sporadic cases or part of a congenital syndrome (Downs, Turners) or systemic illness (galactosemia).
When the cataract diffuses light rays entering the eye, it obstructs the transmission of clear images onto the retina, resulting in abnormal vision.
Significant cause of deprivation amblyopia.

6. Refractive Error Myopia Hyperopia
Nearsightedness – defect in ability to see distant objects
Hyperopia
Farsightedness – inability to see objects at close range and can cause problems with reading.
Unilateral hyperopia can lead to amblyopia.

7. Natural History of Visual System
Ability to focus an image on the retina
Age 2-3 months
Anything that disrupts the stimulation of the visual cortex will likely result in visual impairment.
If left untreated, amblyopia can lead to irreversible blindness.
Duration of amblyopia and the age at onset determine how rapidly normal acuity can be achieved with proper treatment.
Amblyopia from a unilateral congenital cataract requires surgery within the first few months of life and is less effectively treated after 1 to 2 years.
Strabismic amblyopia may be treated effectively up to 4 years of age.
The human visual system is rudimentary at birth; many antatomical and physiologic changes take place during the first few months of life.

8. Natural History of Visual System
Infants are often born with benign eso-or exotropia that resolves within 2 – 3 months of age.
Pseudostrabismus or pseudoesotropia
Appearance of crossed eyes due to a flat nasal bridge, prominent epicanthal folds, or a narrow interpupillary distance.
Should resolve as the child’s nose narrows and becomes more prominent, thus pushing the epicanthal folds away from the eyes.
Refractive errors (decreased visual acuity) is more controversial.
7 – 9% of children grades 1-3 have prescription glasses. Figure rises to 30% by late teens.
Disagreement about whether if left undiscovered refractive error affects academic performance adversely.
Literature supports early detection and treatment of visual impairment to minimize morbidity. Unfortunately, preschool children are often not adequately screened for visual problems, resulting in delays in diagnosis. Primary care providers must be well informed about vision screening and incorporate in into regular health maintenance visits.

9. Primary Prevention Early prenatal care
Screen and immunize women before pregnancy for rubella.
Counsel m0thers regarding potential teratogens
Drugs during pregnancy
LSD exposure can result in coloboma (defect in the uveal tract that can affect several structures including the iris and optic nerve head.
Screening/counseling/Treatment for avoidance of potential maternal infections
Rubella – newborn cataracts, pigmentary, microphtalmia
CMV (cytelomegalovirus) – chorioretinitis, strabismus, optic atrophy, microphthalmia, cataracts. Avoidance of acute viral illness. Mimics Epstein bar virus
Toxoplasmosis – chorioretinitis. Avoid cat litter boxes.
Chlamydia/Gonorrhea – ophthalmia neonatorum, gonorrheal conjunctivitis resulting in corneal ulceration with scarring or perforation of globe. Screen and treat.

10. Primary Prevention Cont…
Birthing/Immediate post-partum
Avoidance of forceps delivery
May result in lid swelling, corneal opacification and laceration, hemorrhage, and rupture of the globe.
Prophylactic Treatment at time of delivery for gonorrhea prophylaxis (does not cover for chlamydia)
1% silver nitrate, 0.5% erythromycin ointment, or 1% tetracycline ointment to neonate’s eyes immediate postpartum

11. Secondary Prevention Clinical screening School based Screening
Complete and accurate history at every well child exam with appropriate follow-up.
Parental concerns
Does the child blink at bright light?
Does the infant regard mother’s face?
Eye examination with appropriate screening guidelines per AAP. See next slide.
School based Screening
School entry based and additional 2 – 3 times during elementary and middle school vision-screening programs
School nurse referrals
Failing screening test, headaches, blurry vision, difficulty in reading, poor school performance.
Most do not have a visual problem – should be screened by primary care first for complete medical history, neurological evaluation, and vision screening.
There is good evidence that early detection and treatment of amblyopia and strabismus in infants and children does improve outcomes. There is evidence that early detection and correction of refractive errors lead to less visual impairment. There is very little evident that screening for refractive errors in school-age children, compared with evaluating those complaining of symptoms or those referred because of parents concerns, results in improved school performance.
Sensitivity of school-based vision-screening programs have been reported to be 60 – 70% and the specificity – 70 – 80%. This means that 20 – 30% of children with normal vision will have abnormal test results and that the positive predictive value of an abnormal test will be 35 – 33%.
Some schools have adopted multiple screening tests including a test for visual acuity, stereo-acuity, and ocular alignment.
Any child referred to a primary care provider for failing a school vision test should undergo an eye examination and office vision screening and be referred to ophthalmologist if a deficit is confirmed.

12. Secondary Screening Recommendations
AAP Recommendations
Advises testing every 1- 2 years through adolescence
American Academy of Ophthalmology and American Optometric Association agree with AAP.
Ages 3 and older
Distance visual acuity
Snellen letters/numbers, Tumbling E, HOTV, Picture tests (Allen figures)
Ocular alignment
Unilateral cover test at 10 ft, Random dot, E stereogram at 40 cm
USPSTF Recommendations
Advises screening of ocular alignment between ages 3- 4.
Does not sanction routine screening for school age children.

13. Clinical Examination
Inspection of ocular structures for symmetry and function
Pupillary response
Appearance of conjunctiva, cornea, iris, and sclera.
Red reflex with opthalmoscope held 12 inches away
Asymmetry of pupils, dark spots within the red reflex or lack of a red reflex should prompt referral.
Presence of white reflex (leukokoria), can indicate retinoblastoma – Ocular emergency.
Age appropriate vision screening every well child exam
Formal vision screening should begin at age 3 years using the most sophisticated test with which the child is able to cooperate.

14. Secondary - Screening Tests
Corneal Light Reflex (Hirschberg Test)
Child looks into penlight. Check light reflected off the corneas is positioned in the center of the pupil and is symmetrical in location.
Normal results with pseudostrabismus; Asymmetry may indicate ocular malalignment which requires follow-up with ophthalmology.
Cover/Uncover Test
Child focuses on an object at a distance with both eyes open. Examiner occludes one eye while looking for movement in the uncovered eye.
Alternate Cover Test
Alternating the cover from one eye to the other without allowing adjustment to binocular vision. If any eye movement is noted, considered an abnormal test result that requires referral to an ophthalmologist.
Despite common use of Hirschberg Test and Cover/uncover Test, there is no information available on their sensitivity and specificity.

15. Secondary - Screening Tests
Eye Charts for Visual Acuity
Allen Cards
Simple pictures held at 10 feet.
2-3 year old children.
Important to verify children are able to identify with the figures before conducting the actual vision test
Tumbling E Chart
Several capital letter E’s oriented in different directions. Child must indicate direction of arms with use of their fingers
4 – 5 year old children
10 – 20 foot distance

16. Secondary – Screening Tests
HOTV Chart
Combination of different sized letters H,O,T,V. Provider points to a letter, then child points to a matching letter on hand held card.
3 to 5 year old children
10 – 20 foot distance
Snellen Acuity Chart
Letters and numbers. Best used with school aged children
Optec Vision Testing System
Evaluates near and far visual acuity, phorias, color and contrast vision.
Child looks into a viewer, examiner selects a test. Less peripheral distraction than wall chart.
More costly for system.

17. Secondary – Screening Tests
Normal Visual Acuity Results
20/40 – normal for 3 year-olds
20/30 – normal for 4 year-olds
20/20 – normal for 5 – 6 year-olds
A difference of more than one line between the two eyes is abnormal and may indicate amblyopia or a refractive error.
Requires a referral to an ophthalmologist

18. Secondary - Screening Tests
Stereoscopic Testing
Detects amblyopia and strabismus.
Binocular vision develops by four months of age.
AAP recommends the unilateral cover test or random dot E stereogram to test for ocular alignment.
Random dot E stereogram test – page of dots. Child places on a pair of three-dimensional glasses that enable the child to see geometric figures such as a letter E.
Children with amblyopia will not see these shapes.
Test is easy to administer and only takes a few minutes.

19. Secondary – Screening Tests
Photorefraction
Standard refraction testing involves determining the proper eyeglass lens to correct vision.
Photorefraction is a photographic technique designed to detect ocular anomalies by using a light reflex that is generated by placing a flash source slightly above or below a camera lens.
Identifies refractive error, ocular alighment, and clarity of lens
Compact and easy to use
Does not require a response from the child
Limitations include expense and delay in obtaining results. (Film usually sent out for processing and analysis).

20. Tertiary Prevention Assist with referrals Treatment monitoring
For vision impaired – assist and encourage development of socialization skills.
Assist with IEP planning in the school program
Encourage and support parents.

21. Common Errors Not providing screening Lack of follow-up
Performing tests improperly
Referrals for pseudostrabismus

22. Emerging Trends Screening
New computer based programs for mass testing and more accurate testing.
Assistance for Visually Impaired Child
Technological advances
Camera used to project enlarged newsprint for child to read
Web sites for visually impaired
Validation of Current Screening tests and their benefits
Studies needed to document sensitivity and specificity of commonly used screening tests.
Accuracy can then be compared with new automated screening devices.
Studies to validate cost-effectiveness of universal, periodic visual acuity screening in schools.
More exploration of the relationship of asymptomatic refractive errors to school performance and outcomes.
School health resources are not sufficient to continue to support mass interventions of no value or unproven benefit.

23. Color Vision Testing Ishihara color plates Males 8% deficient
Females 0.5% deficient
Test in 3rd to 7th grade

24. Vision Screening
Birth
Observation and inspection
Red reflex testing

25. Vision Screening 4-6 months of age Observation and inspection
Corneal light reflex testing
Bruchner red reflex testing

26. Vision Screening Toddler Observation and inspection
Corneal light reflex testing
Bruchner red reflex testing
Cover test for alignment
Cover test for amblyopia or organic vision loss

27. Vision Screening Pre-school Observation and inspection
Corneal light reflex testing
Bruchner red reflex testing
Cover test for alignment
Cover test for amblyopia or organic vision loss
Distance visual acuity

28. Vision Screening School-age Observation and inspection
Corneal light reflex testing
Bruchner red reflex testing
Cover test for alignment
Cover test for amblyopia or organic vision loss
Distance visual acuity
Other optional tests

29. Vision Screening Pearls
Infants and Toddlers
Toy over light allows easier and more accurate corneal light reflex testing
Bruchner red reflex testing underutilized but valuable
“Objects to cover” may equal Amblyopia

30. Vision Screening Pearls
Pre-school and School-age
Make testing fun
Beware of the ‘professional peeker’
Testing at 10 feet may be better