This is the current release of the guideline.

This guideline updates a previous version: American Optometric Association. Care of the patient with learning related vision problems. St. Louis (MO): American Optometric Association; 2000 Jan 1. 60 p. (Optometric clinical practice guideline; no. 20).

Learning related vision problems

School-age children with learning related vision problems

Diagnosis/Evaluation

1. Patient history
2. Visual efficiency evaluation
   • Visual acuity
   • Refraction
   • Ocular motility and alignment
   • Accommodative-vergence function
   • Physical diagnosis
3. Visual information processing evaluation
   • Visual spatial orientation skills
   • Visual analysis skills
   • Rapid naming
   • Executive functions
4. Supplemental testing
   • Reading and spelling
   • Comprehensive assessment battery
   • Phonological processing
   • Magnocellular pathway function

Management

1. Refractive correction
2. Vision therapy
3. Lenses and prisms
4. Referral
5. Parent and patient education

The guideline developer performed literature searches using the following electronic databases:

• Ovid: MedLine, EMBASE, PsycINFO, Global Health
• Web of Science
• Table of contents (electronic): Journal of the American Medical Association, New England Journal of Medicine, Journal of Clinical Epidemiology, British Medical Journal, Health Service Res, Journal of Public Health
• Guidelines International Database

The time frame of the literature search was from 2000 (last review period) and forward.

Data and new references were included if the team found groups of published papers to include the same data and/or if the team consensus was to include based on the research results (no ranking criteria were used).

All terms related to the learning related vision problems of all ages, especially children, and ocular and systemic manifestations were included in the literature search.

Not stated

Not applicable

Not stated

The American Optometric Association (AOA) Guidelines Review Committee reviews the list of all AOA guidelines per year for currency and solicits experienced and reputable writers to work on guidelines. Together with the writer, references are searched for new information to include or exclude from the current guideline. This team is diversified to include clinical practice doctors, academicians, researchers, and volunteer members from around the country ranging in age, race, ethnicity, gender, and location.

The Committee reviews all resources/references and searches that produce literature for review. After the guideline is updated, the committee re-convenes to review all literature cited in the draft one more time for accuracy.

Not applicable

A formal cost analysis was not performed and published cost analyses were not reviewed.

The Reference Guide for Clinicians was reviewed by the American Optometric Association (AOA) Clinical Guidelines Coordinating Committee and approved by the AOA Board of Trustees.

Early Detection

Because the evidence that learning related vision problems can be prevented to any substantial degree is inconclusive, the emphasis is on early detection. It is recommended that vision examinations be scheduled at 6 months, 3 years of age, and at entry into school, at which time the parents should complete a developmental questionnaire. If there is a history of developmental delay, a screening test like the Denver II can be performed. When visual information processing problems are suspected, a more extensive evaluation is necessary for the early identification of the child at risk for the development of learning related vision problems.

Care Process

1. General Considerations

   Care of the patient with learning related vision problems involves taking a patient history and examining visual efficiency, visual information processing ability, and visual pathway integrity. The 2002 American Optometric Association (AOA) Optometric Clinical Practice Guideline: Pediatric Eye and Vision Examination should be consulted for additional information.

2. Patient History

   The patient history is the initial component of the care process and an important part of an appropriate diagnosis. Collection of demographic data usually precedes and supplements the history taking. A questionnaire completed by the parent or caregiver can facilitate the history process. Special attention should be directed to developmental milestones and academic performance. Questions should be constructed to define the specific nature of the learning and vision problems and should be used as a guide for the subsequent testing sequence. Information obtained directly from teachers or therapists can be helpful.

   Language delays are common in individuals with learning problems. As a result, sufficiently detailed descriptions of learning or visual symptoms obtained directly from the patient may be lacking. This could result in an underestimation of the severity of the symptoms and should not be the exclusive source of such information.

   A comprehensive patient history for learning related vision problems may include:

   1. Chief concern or complaint
   2. History of present illness (e.g., patient visual or ocular history)
   3. Patient medical history (e.g., exploration of risk factors: perinatal events, childhood illnesses)
   4. Developmental history (e.g., gross motor, fine motor, language, personal/social milestones)
   5. Family history (e.g., visual/ocular, medical, academic/educational)
   6. Academic/educational history (e.g., previous assessments and interventions; current assessment, interventions and placement; current achievement levels; academic/education-related medical history)
3. Visual Efficiency Evaluation

   Visual efficiency problems are related to learning achievement. An analysis of the literature on the subject indicates that refractive error—in particular hyperopia and significant anisometropia, accommodative and vergence dysfunctions, and eye movement disorders—are associated with learning problems. Therefore, a thorough clinical investigation for the presence of these conditions in the individual with learning problems is important.

   Though they are extremely important functional vision disorders to diagnose and treat early, other binocular vision disorders such as constant strabismus and amblyopia, have not been found to be associated with learning problems.

   Some patients with visual information processing deficiencies, particularly deficiencies of discrimination and memory, may have difficulty making reliable responses during subjective testing. The clinician may have to make necessary compensations or use alternative testing procedures to obtain relevant information. Reliance on objective findings for clinical decision-making may be necessary.

   1. Visual Acuity

      Assessment of visual acuity in patients with learning related vision problems should be measured monocularly and binocularly at distance and near point. Patients with sufficient verbal communication who know the alphabet can be tested using a Snellen chart. If difficulties are encountered, an assessment of visual acuity may include the following methods:

      • HOTV
      • Broken Wheel
      • Tumbling E

      The 2002 AOA Optometric Clinical Practice Guideline for the Pediatric Eye and Vision Examination should be consulted for additional information.

   2. Refraction

      The measurement of refractive error should include:

      • Static retinoscopy
      • Subjective refraction

      Because of the importance of detecting hyperopia—particularly latent hyperopia—proper fogging technique should be maintained during retinoscopy and subjective refraction. A cycloplegic refraction may be indicated if latent hyperopia or pseudomyopia is suspected, or if convergence excess or accommodative insufficiency is diagnosed.

   3. Ocular Motility and Alignment

      Ocular motility is typically evaluated by chair side tests of fixation stability, and of saccadic and smooth pursuit eye movements. In addition to investigation of basic neurological and extraocular muscle function in patients with learning related vision problems, qualitative analysis of their ocular motility is necessary.

      The following standardized observational rating systems have been developed:

      • NSUCO (Northeastern State University College of Optometry)
      • SCCO 4+ (Southern California College of Optometry)

      For smooth pursuit testing, both of these systems involve tracking a target moving in a circle. Evaluation of performance is by gain (eye velocity in relation to target velocity) and the number of catch-up saccades to reacquire the target.

      Both systems investigate predictive saccades between two fixed targets positioned centrally, equidistant from the midline. Hypometric inaccuracies are commonly found in individuals with poor saccadic eye movement control. Excessive head and body movements (motor overflow) frequently accompany ocular motility deficiencies. The clinical signs and symptoms of ocular motility deficiencies can be found below.

      Signs and Symptoms of Ocular Motility Dysfunction

      • Moving head excessively when reading
      • Skipping lines when reading
      • Omitting words and transposing words when reading
      • Losing place when reading
      • Requiring finger or marker to keep place when reading
      • Experiencing confusion during the return sweep phase of reading
      • Experiencing illusory text movement
      • Having deficient ball-playing skills

      Assessment tools are available for a more quantitative evaluation, albeit indirect, of saccadic eye movements. The following available tests, which are norm-referenced for the patient's age and grade in school, clearly indicate the developmental course of skill improvement:

      • Developmental Eye Movement Test (DEM)
      • King-Devick Saccade Test (K-D)

      Unfortunately, naming tasks confound the results because both eye movement skill and naming speed are required to complete the test successfully. However, because the DEM incorporates a subtest of naming speed that isolates eye movement skill for a more specific clinical diagnosis, its use is preferred.

      Infrared eye-monitoring systems that directly compute reading eye movements (e.g., Visagraph II, ReadAlyzer) are also available. Although they do not measure saccade dynamics (accuracy, latency) or main sequence, these assessment tools provide a simulation of eye movements over the text. Information is available on the number of fixations required to read a sample of text, the duration of fixation, as well as the number of regressions and reading rate, and by inference, the putative span of recognition (span of attention or perceptual span)—the spatial region (number of character spaces) from which the reader extracts information during a fixation—which may be narrow in disabled readers. Particular interest should be paid to return sweep saccades, which are presumably dominated by visual and ocular motor control processes.

      Eye alignment is usually determined by a distance and near cover test. If a strabismus is found, the 2004 AOA Optometric Clinical Practice Guideline for the Care of the Patient with Strabismus: Esotropia and Exotropia should be consulted for additional information.

   4. Accommodative-Vergence Function

      Evaluation of accommodation and vergence amplitude, facility, accuracy, consistency, and sustainability is required and may include the following procedures or measurements:

      • Cover test
      • Near point of convergence
      • Heterophoria, distance and near
      • Fusional vergence amplitudes, distance and near
      • Vergence facility
      • Amplitude of accommodation
      • Accuracy of accommodation (lag)
      • Relative accommodation
      • Accommodative facility
      • Fixation disparity analysis
      • Stereopsis

      The evaluation of accommodation and vergence should include assessment of both the range and facility of response. The clinical signs and symptoms of accommodative and vergence dysfunctions can be found below. The 2006 AOA Optometric Clinical Practice Guideline for the Care of the Patient with Accommodative and Vergence Dysfunction provides for more detailed assessment information.

      Signs and Symptoms of Accommodative - Vergence Dysfunctions

      • Asthenopia when reading or writing
      • Headaches associated with near visual tasks
      • Blurred vision at distance or near
      • Diplopia at distance or near
      • Decreased attention for near visual tasks
      • Close near working distance
      • Overlapping letters/words in reading
      • Burning sensations or tearing of the eyes during near visual tasks
   5. Physical Diagnosis

      The assessment of visual system integrity should include:

      • Evaluation of the anterior segment
      • Evaluation of the posterior segment
      • Color vision testing
      • Assessment of pupil responses
      • Visual field screening

      Standard testing procedures for the evaluation of visual system integrity can be used in patients with learning related vision problems. For additional information consult the 2002 AOA Optometric Clinical Practice Guideline for the Pediatric Eye and Vision Examination.

4. Visual Information Processing Evaluation
   1. General Considerations

      The visual information processing skills that require testing are visual spatial orientation skills, visual analysis skills, including auditory-visual integration, visual-motor integration skills, and rapid naming. When available, norm-referenced tests are preferred for this purpose. Testing should be conducted uniformly and according to the exact methods specified in the test instructions. Specified rule-based scoring procedures should be followed. Qualitative insights from observation of the test taker's behavior can provide important supplementary information for diagnosis and management. Attention to task, ability to understand the instructional set, cognitive style, problem-solving ability, frustration tolerance, and excessive motor activity are some of the behaviors worth observing.

      Testing should be done without interruption in a relatively quiet environment. Individuals with attention deficits may require rest periods between tests or multiple testing sessions. For a comprehensive visual information processing evaluation, one or two tests from each category can be selected for administration. For a detailed or problem-focused evaluation of a specific visual information processing skill, multiple tests from the same category can be administered.

   2. Visual Spatial Orientation Skills

      The clinical signs and symptoms of visual spatial orientation skill deficiencies are listed below.

      Signs and Symptoms of Visual Spatial Orientation Skill Deficiency

      • Delayed development of gross motor skills
      • Decreased coordination, balance, and ball-playing skills
      • Confusion of right and left
      • Letter reversal errors when writing or reading
      • Inconsistent directional attack when reading
      • Inconsistent dominant handedness
      • Difficulty in tasks requiring crossing of the midline

      Visual spatial orientation skills can be evaluated by several categories of tests.

      1. Bilateral Integration
         • Body Knowledge and Control - Standing Test
         • Chalkboard Circles Test
      2. Laterality and Directionality
         • Piaget Right-Left Awareness Test
         • Reversals Frequency Test (RFT)
         • Jordan Left-Right Reversal Test – Revised
         • Test of Pictures/Forms/Letters/Numbers Spatial Orientation & Sequencing Skills (TPFLNSOSS)
   3. Visual Analysis Skills
      1. Non-motor Skills

         Non-motor visual analysis skills have traditionally been subdivided into separate theoretical constructs: visual discrimination, visual figure-ground discrimination, visual closure, visual memory, and visualization.

         The clinical signs and symptoms of non-motor visual analysis skill deficiencies are listed below:

         Signs and Symptoms of Non-Motor Visual Analysis Skill Deficiency

         • Delayed learning of the alphabet
         • Poor automatic recognition of letters and words (sight word vocabulary)
         • Difficulty performing basic mathematics operations
         • Confusion between similar-looking words (letter transpositions)
         • Difficulty in visual search-like tasks
         • Difficulty spelling nonregular words
         • Crowding-like spatial confusion when viewing coincident visual stimuli
         • Difficulty with classification of objects on the basis of their visual attributes (e.g., shape, size)
         • Poor automatic recognition of likenesses and differences in visual stimuli
         • Difficulty with remembering the proper sequence of visual stimuli
      2. Visual-Motor Integration

         Visual-motor integration involves three individual processes: visual analysis of the stimulus, fine-motor control (or eye-hand coordination), and visual conceptualization, which includes the integration process itself. Deficits in any one of these processes will influence the overall result. Testing fine-motor coordination is therefore important for a differential diagnosis.

         The clinical signs and symptoms of visual-motor integration skill deficiency are listed below:

         Signs and Symptoms of Visual-Motor Skill Deficiency

         • Difficulty copying from the chalkboard
         • Writing delays, mistakes, confusions
         • Letter reversals or transpositions when writing
         • Poor spacing and organization of written work
         • Difficulty maintaining written work on printed lines
         • Misalignment of numbers in columns when doing math problems
         • Poorer written spelling than oral spelling
         • Poor posture when writing, with or without torticollis
         • Exaggerated paper rotation(s) when writing
         • Awkward pencil grip

         Visual-motor integration can be tested with the following:

         • Beery-Buktenika Developmental Test of Visual Motor Integration, Fifth Edition (VMI)
         • Test of Visual-Motor Skills – Revised (TVPS-R)
         • Wide Range Assessment of Visual Motor Abilities (WRAVMA)
         • Copying subtest of the Developmental Test of Visual Perception, Second Edition (DTVP-2)
         • Bender Visual-Motor Gestalt Test, Second Edition
         • Full Range Test of Visual-Motor Integration (FRTVMA)
         • Rosner Test of Visual Analysis Skills
         • Wold Sentence Copying Test
      3. Fine-Motor Coordination

         The following instruments can test fine-motor coordination:

         • Grooved Pegboard Test
         • Eye-Hand Coordination subtest of the Developmental Test of Vision Perception, Second Edition (DTVP-2)
         • Motor Coordination Supplement of the Beery-Buktenika Developmental Test of Visual-Motor Integration, Fifth Edition (VMI)
         • Bead Threading subtest of the Dyslexia Screening Test (DST).
      4. Auditory-Visual Integration

         The clinical signs and symptoms of auditory-visual integration deficiency are presented below:

         Signs and Symptoms of Auditory-Visual Integration Deficiencies

         • Difficulty with sound-symbol associations
         • Difficulty with spelling
         • Difficulty learning the alphabet

         Auditory-visual integration can be tested with the:

         • Auditory-Visual Integration Test
   4. Rapid Naming

      Testing of rapid naming requires the naming of arrays of visually presented numbers, letters or objects. The clinical signs and symptoms of rapid naming deficiency are listed below:

      Signs and Symptoms of Rapid Naming Deficiencies

      • Impaired reading fluency
      • Faulty sight word vocabulary (word recognition)
      • Difficulties in reading comprehension
      • Difficulty learning the alphabet (letter identification)

      Rapid naming can be tested with the following:

      • Vertical subtest of the Developmental Eye Movement Test (DEM)
      • Rapid Automatized Naming and Rapid Alternating Stimulus Tests (RAN/RAS)
      • Rapid Naming subtest of the Dyslexia Screening Test (DST)
   5. Executive Functions

      Executive functions are required for any goal-directed behavior. They allow the anticipation of outcomes and adaptation to changing situations. The signs and symptoms of executive function deficiencies are listed below:

      Signs and Symptoms of Executive Function Deficiencies

      • Impaired reading fluency
      • Difficulty completing tasks in the designated time
      • Poor sustained attention
      • Distractibility
      • Difficulty switching between tasks
      • Poor planning of visually oriented tasks

      Executive function can be tested with the following:

      • Symbol Digit Modalities Test (SDMT)
      • Children's Trail Making Test (CTMT)
      • Children's Color Trail Test (CCTT)
      • Wisconsin Card Sorting Test – Revised (WCST-R).

5. Supplemental Testing
   1. Reading Disability Subtypes

      One popular approach is the achievement classification model based on performance in word recognition and spelling tasks. Standardized tests that are available to measure these parameters include:

      • Boder Test of Reading-Spelling Patterns
      • Dyslexia Determination Test, Third Edition

      Analysis of the types of spelling errors made is used to subtype the reading problem into dyseidetic, dysphonetic, or mixed type. The dyseidetic subtype is characterized by visual information processing deficits, including visual memory and visualization. There is a limited sight word vocabulary and an over-reliance on phonetic decoding strategies that interfere with efficient reading. Poor understanding and application of phonetic decoding rules characterizes the dysphonetic subtype. Meanwhile visual information processing capacity is relatively strong. However, it is important to note that this reading disability subtype has been associated with magnocellular visual pathway deficits.

   2. Comprehensive Assessment Battery

      The following comprehensive assessment batteries are suggested:

      • Dyslexia Screening Test – Junior (DST-J)
      • Dyslexia Screening Test – Secondary (DST-S)
   3. Phonological Processing

      Standardized tests that are available to analyze phonological processing abilities:

      • Phonemic Segmentation subtest of the Dyslexia Screening Test (DST)
      • Rhyme subtest of the Dyslexia Screening Test (DST)
      • Nonsense Passage Reading subtest of the Dyslexia Screening Test (DST)
      • Rosner Test of Auditory Analysis Skills (TAAS)
      • Phonological Awareness Test-2 (PAT-2)
      • Test of Phonological Awareness Skills (TOPAS)
   4. Magnocellular Pathway Function

      Presently, there are no standard clinical tests readily available to clinicians for the evaluation of magnocellular function. The most promising tests are visual evoked potentials using low-contrast, low-spatial frequency stimuli, and psychophysical motion detection paradigms.

6. Assessment and Diagnosis

   All data obtained from testing should be evaluated to establish one or more clinical diagnoses and to develop a management plan. Examination of the patient history, clinical signs and symptoms, test results and behavioral observations, and review of previous reports and present levels of care are necessary to accomplish this. Low test scores should be referenced to the expected signs and symptoms of that deficiency.

   In the analysis of the visual efficiency performance data obtained, it is necessary to examine all of the data collectively by a standard clinical protocol, rather than relying on a single finding to arrive at a diagnosis. The 2006 AOA Optometric Clinical Practice Guideline for the Care of the Patient with Accommodative and Vergence Dysfunction provides lists and descriptions of common accommodative and vergence dysfunctions and methods of data analysis.

   For testing visual information processing the use of z (or standard) scores is recommended. The z-score is the deviation of a specific test score from the mean, expressed in standard deviation units. It allows the expression of any score as a percentile rank by comparing it to a standard normal distribution. A test result with a z-score that is ≥1.5 standard deviations below the mean (percentile rank = 6.68) should definitely be considered anomalous and clinically significant. Scores falling between 1.0 and 1.5 standard deviations below the mean should be considered suspicious and perhaps clinically relevant, depending on the overall clinical picture, the nature and type of the learning problem, and the level of overall cognitive function.

   Parents and school systems often prefer the expression of performance as an age or grade equivalent, or as a percentile rank, to enable direct comparison with expected performance levels. It is important to relate visual information processing test results to the current level of cognitive function as measured by IQ tests (such as the Wechsler Intelligence Scale for Children – IV or Stanford-Binet Intelligence Scales, Fifth Edition). In the case of individuals with low average IQ scores, overall performance in visual information processing in the same range may not be indicative of a problem, but rather the expected level of performance.

7. Management

   The goal of the management of learning related vision problems is to prepare the individual to take full advantage of the opportunities for learning. In most situations, optometric intervention for learning related vision problems is delivered in conjunction with other professionals involved in the management of the learning problem from an educational or medical perspective. Interdisciplinary communication, consultation, and referral are vital for the most effective management of the individual with learning problems.

   The management of learning related vision problems should be directed at the identification and treatment of specific visual deficits.

   Learning related vision problems are usually managed in a progressive sequence. Treatment should begin with consideration of refractive status. Careful attention should be paid to the correction of hyperopia and anisometropia because of their known association with learning problems.

   Next, visual efficiency deficits should be treated aggressively, using lenses, prisms, and vision therapy. The 2006 AOA Optometric Clinical Practice Guideline for the Care of the Patient with Accommodative and Vergence Dysfunction offers more detailed management recommendations. The specific goal for the treatment of visual efficiency deficits is enhancement of the range, latency, accuracy, facility, and sustainability of accommodative and vergence responses. At the conclusion of therapy, ocular motility should be more accurate, and the incidence of accompanying head and body movement lower.

   The goals for visual information processing therapy can be found in Table 9 of the original guideline.

   Vision therapy is usually conducted in the optometrist's office, with prescribed home support activities. One or two office visits per week for 12 to 24 weeks may be required for uncomplicated cases. Office therapy sessions usually begin with review of the activities assigned for practice at home. This review should include a demonstration of the procedures and an indication of the level of compliance.

   Supportive activities performed at home 4 to 5 days per week for 20 to 30 minutes each time are an important adjunct to office-based therapy, providing continuity of care and enhancing opportunities for practice and mastery of skills. Consistent application of supportive activities at home may reduce the number of office visits required and the potential for regression.

   Many vision therapy techniques and procedures available to address visual information processing problems are described in several recommended compilations. Computerized vision therapy programs are available for office and home therapy.

   After this initial period of therapy, a re-evaluation should be performed, using the same visual information processing tests employed previously, and an exploration of improvements in clinical signs and symptoms made. An improvement in test performance of at least 1.5 standard errors of measurement is considered clinically significant. Additional therapy may be indicated if clinical signs and symptoms—although improved—persist to some degree. When the patient has made sufficient progress, and has achieved the major therapeutic goals for visual information processing skill enhancement and reduction in clinical signs and symptoms, a home-based maintenance program should be recommended. This maintenance program can include practicing a few procedures 2 to 3 times per week for 10 to 15 minutes each time for 3 months.

   When underlying neurological problems, cognitive deficits, or emotional disorders are suspected, referral to another health care professional or the educational system may be indicated. Occupational or physical therapy can complement optometric vision therapy when the deficiencies are severe.

8. Parent and Patient Education

   Specific communication with the patient's parents or caregivers should occur after the examination to review the test outcomes. This discussion should begin with a review of the chief complaint. An explanation of the nature of the vision problem and its relationship to the presenting signs and symptoms is necessary. The management plan and prognosis should be presented to the patient and parents or caregivers. Communication with education professionals about the diagnosis, proposed management plan, and expected outcomes should be initiated. This should lead to a coordinated effort with the patient's classroom teachers, special education teachers, and therapists. The importance of continuing eye care should be discussed with parents or caregivers. Other education and health care professionals should be informed about the presence and nature of the learning related vision problems and their relationship to extant learning difficulties.

None provided

The type of evidence supporting the recommendations is not specifically stated.

Optometric intervention directed toward improving visual function has been shown to be efficacious. It does not replace conventional educational programming but is a necessary complementary intervention to maximize the learning environment and the effectiveness of pedagogy.

Additional benefits include:

• Improved quality of care for patients with learning related vision problems
• Minimized adverse effects of learning related vision problems
• Enhanced quality of life

Not stated

Clinicians should not rely on the Clinical Guideline alone for patient care and management. Refer to the listed references and other sources the original guideline for a more detailed analysis and discussion of research and patient care information.

An implementation strategy was not provided.

Not applicable: The guideline was not adapted from another source.

American Optometric Association

American Optometric Association Consensus Panel on the Care of the Patient with Learning Related Vision Problems

Panel Members: Ralph P. Garzia, O.D. (Principal Author); Eric J. Borsting, O.D.; Steven B. Nicholson, O.D.; Leonard J. Press, O.D.; Mitchell M. Scheiman, O.D.; Harold A. Solan, O.D.

American Optometric Association (AOA) Clinical Practice Guidelines Coordinating Committee Members: David A. Heath, O.D. (Chair); John F. Amos, O.D., M.S.; Stephen C. Miller, O.D.

Not stated

This is the current release of the guideline.

This guideline updates a previous version: American Optometric Association. Care of the patient with learning related vision problems. St. Louis (MO): American Optometric Association; 2000 Jan 1. 60 p. (Optometric clinical practice guideline; no. 20).

Electronic copies: Available in Portable Document Format (PDF) from the American Optometric Association (AOA) Web site .

Print copies: Available for purchase from the American Optometric Association (AOA), Order Department, 243 North Lindbergh Boulevard, St. Louis, MO 63141; Telephone (800) 262-2210 (U.S. only).

None available

None available

This summary was completed by ECRI on March 1, 2001. It was verified by the guideline developer as of May 16, 2001. This summary was updated by ECRI Institute on October 11, 2011. The updated information was verified by the guideline developer on November 9, 2011.

This NGC summary is based on the original guideline, which is subject to the guideline developer's copyright restrictions as follows:

Copyright to the original guideline is owned by the American Optometric Association (AOA). NGC users are free to download a single copy for personal use. Reproduction without permission of the AOA is prohibited. Permissions requests should be directed to Jeffrey L. Weaver, O.D., Director, Clinical Care Group, American Optometric Association, 243 N. Lindbergh Blvd., St. Louis, MO 63141; (314) 991-4100, ext. 244; fax (314) 991-4101; e-mail, JLWeaver@AOA.org.