Objective testing of vergence ranges.

BACKGROUND: Testing of vergence ranges is a routine clinical procedure providing valuable information about the patient's binocular status. Unfortunately, obtaining this information from non-verbal or very young patients has proven difficult or impossible in many situations, due to lack of subjective response. This study explored a new prism bar technique for obtaining vergence ranges using an objective procedure in a randomized, modified examiner-masked routine that allows for vergence measurement without a verbal response. METHODS: In the first of two experiments, subjective and objective vergence ranges at 40 cm were obtained using a nonluminous target (printed picture of dog's head) from 29 adult subjects. The second experiment compared a self-illuminated target (transilluminator) to that of the nonluminous target in subjective and objective vergence range measurements using nine subjects from the first experiment. RESULTS: The results of both of these experiments suggest that, at least in the adult population, the vergence range values obtained objectively compare favorably with those obtained subjectively. However, the transilluminator yielded greater variance for all measures and, for one variable, base-out to break, did yield statistically different results between objective and subjective findings. CONCLUSIONS: Objective and subjective vergence range measurements appear to yield consistently comparable results in the adult population. The use of a non-luminous target appears to yield more consistent results, most likely due to the poor accommodative nature of a self-illuminated target (transilluminator).

Efficacy of a pediatric cycloplegic administered as a spray.

BACKGROUND: The topical administration of eyedrops is often an unpleasant procedure in the pediatric population. We sought to learn whether a combination mydriatic-cycloplegic solution would be an effective cycloplegic if delivered as a spray. METHODS: We conducted a prospective, examiner-masked, parallel-group study and randomized 38 subjects (age range 6 months to 12 years, mean = 7.3 years) into four groups such that the same combination mydriatic-cycloplegic solution was administered under the following conditions: 1) eyedrops to eyes that were open; 2) eyedrops to eyes that were closed; 3) spray to eyes that were open; 4) spray to eyes that were closed. Both eyes of each subject received the solutions administered under one of the four conditions. Residual accommodation was measured using dynamic retinoscopy and the subjective push-up method, where applicable, at times 0, 10, 20, 30, 45, and 60 mins following administration of the medications. RESULTS: Repeated measures analysis of covariance revealed no statistically significant difference (p > 0.05) in cycloplegic efficacy among the four methods of drug delivery. CONCLUSIONS: The results of this study suggest that administering cycloplegics by spray to the closed eye is as efficacious as instilling eyedrops to the open eye. Use of a cycloplegic spray can have important clinical advantages compared to conventional cycloplegic eyedrops administered to children.

Mydriatic efficacy of a cycloplegic spray in the pediatric population.

BACKGROUND: The topical administration of eyedrops is often an unpleasant procedure in the pediatric population. We sought to learn whether a combination mydriatic-cycloplegic solution would be an effective mydriatic if applied as a spray. METHODS: We used a prospective, examiner-masked, parallel-group study design and randomized 38 subjects (age range 6 months-12 years, mean = 7.3 years) into four groups such that the same combination mydriatic-cycloplegic solution was administered under the following conditions: 1) eyedrops to eyes that were closed; 2) eyedrops to eyes that were open; 3) spray to eyes that were closed; 4) spray to eyes that were open. Both eyes of each subject received the solutions administered under one of the four conditions. Photographs were taken of each subject's pupils at times 0, 5, 15, 25, 40, and 55 mins following administration of the medications. RESULTS: Repeated measures analysis of variance revealed no statistically significant difference (p > 0.05) in mydriatic efficacy among the four methods of drug administration. CONCLUSIONS: The results of this study suggest that the mydriatic efficacy of a mydriatic-cycloplegic spray is comparable to that associated with eyedrop instillation. Mydriatic sprays may have important clinical advantages over conventional ophthalmic solutions in the pediatric population.

Diagnosis and management of reading dysfunction for the primary care optometrist.

A model for the identification/diagnosis and management of reading dysfunction for the primary care optometrist is presented. The model is based upon clinical experiences in both private and academic practice and an extensive review of the literature. The model, illustrated in a series of flow charts and a table, incorporates the major perceptual dysfunctions typically encountered by patients who present with reading problems. The first part of the model, labeled fundamental, demonstrates the minimum diagnostic and management techniques for those children who appear to have reading dysfunction. The second part of the model, labeled complex, provides a more extensive diagnostic and management approach. The validity of the approach is further illustrated in a series of 13 arbitrarily selected cases of reading dysfunction which are statistically analyzed. Robust correlations are found among different tests of visual-motor skills (Bender, Test of Visual Analysis Skills), a test of short-term memory (Getman-Henderson-Marcus Test of Visual Recall), and reading decoding. Modest correlation is also found between a test of auditory perception, The Test of Auditory Analysis Skills (TAAS) and reading decoding. Direct testing for dyslexia using the Dyslexia Determination Test illustrates that not all those with reading dysfunction are dyslexic.

A survey of the vision assessment of the developmentally disabled and multi-handicapped in University Affiliated Programs (UAPs).

In 1989 we conducted a survey to assess the availability of vision assessments (screening and complete eye/vision examinations) in University Affiliated Programs for Persons with Developmental Disabilities (UAPs). Analysis of the results suggests that although the UAPs are continuing to provide some services for eye/vision care, only 58 percent of these centers have facilities for the screening of vision problems. Ninety-six percent of the respondents, however, feel that vision screening is important. The developmentally disabled and multi-handicapped child is at high risk for vision/eye problems. Unless this difference between service availability and the perceived importance of vision services is addressed, there is an increased risk that the child may not reach his/her full potential. The UAPs need to increase the availability of eye/vision care within the UAPs and to expand training to providers in the community to deal with the developmentally disabled and multi-handicapped.

Norrie's disease vs. PHPV: one family's dilemma.

This paper presents the numerous similarities between Norrie's disease and bilateral persistent hyperplastic primary vitreous. A description of each disease is given, as well as a case report which demonstrates the difficulty in distinguishing the two disease processes when there is a negative family history of blindness. A discussion section focuses on the need for a better differential protocol for Norrie's disease, which would aid the clinician when a family history of blindness is absent.

Aging-related foveal flicker sensitivity losses in normal observers.

Photopic flicker sensitivity for healthy subjects over 60 years of age was compared with that of subjects in their 20s and 30s. The stimulus was achromatic and viewed foveally through a 2.0-mm artificial pupil which assured a constant pupil size in all subjects. As a group, older subjects had lower flicker sensitivity than younger subjects. This was found even when the retinal illuminance difference between age groups that arises from increased lens absorption in older adults was taken into account. The results indicate that a reduction in retinal illuminance with age cannot account for all the flicker sensitivity losses in older adults.

A comparison of cycloplegic refraction to the near retinoscopy technique for refractive error determination.

The near retinoscopy technique of refractive error determination was compared to the standard method of cycloplegic refraction using 10 "infants" (3-12 months of age) and 10 "children" (32-109 months of age). There was a significant difference between the techniques for both sphere and cylinder power. Although there was no interaction of refractive technique and age group, the difference between near retinoscopy and cycloplegic refractive error tended to be larger for infants than for children. No significant difference was found when the average refractive values were compared for monocular or binocular conditions and no significant effect was found for either gender or laterality (right versus left eye). Based on these findings, it is suggested that caution be used in substituting the near retinoscopy technique for cycloplegic refraction even utilizing a "correction" factor for the dioptric difference between techniques.

Clinical and ocular findings in the Brachmann-de Lange syndrome.

The Brachmann-de Lange syndrome (BDLS) is a congenital abnormality of unknown etiology and variable expressivity, presenting with a characteristic facial appearance, external abnormalities, and clinical features. We report on the external and ocular findings in three cases of BDLS. We note ocular findings not previously seen in the disorder. A large hyperopic ametropia was found in two cases, and lenticular cataracts were noted in one case. Further case studies are necessary to determine if these conditions are consistent in the BDLS.

Optometry's role in reading disabilities: resolving the controversy.

Optometry's involvement in the management of reading disabilities is often misunderstood. This paper clarifies the confusion surrounding specific reading disabilities and optometric vision therapy in the management of them. Topics include a historical review of dyslexia, theories of brain function, and a neuroanatomical model, as well as operational definitions and behavioral characteristics of the types of dyslexia. Methods for direct diagnosis of coding deficits in specific reading disability (dyslexia) are discussed. This approach explains the beneficial role of optometric vision therapy in the management of patients with reading problems.

Expanding the limits of the Teller Visual Acuity Cards.

A nomogram is presented that permits quick determination of Snellen visual acuity values for the Teller Visual Acuity Cards at distances up to 10 feet. With this nomogram, it is now possible to determine visual acuity in nonverbal populations, other than infants, while taking into account the effect of refractive error, especially myopia. The formula for constructing the nomogram is also included as generated by the Lotus 1-2-3 spreadsheet.

The relationship between the Test for Visual Analysis Skills (TVAS) and standardized visual-motor tests in children with visual perception difficulty.

Two widely utilized tests for visual-motor integration are the Beery Test for Visual Motor Integration (VMI) and the Bender Visual-Motor Gestalt Test (Bender). Another test that appears to demonstrate good potential for the measurement of visual-motor performance is the Test for Visual Analysis Skills (TVAS). This study examines the difference in performance on these tests between a pediatric population derived from available standardized data, a concurrent normal clinical population and a referred population of children with visual perception difficulties. The results indicate that all three tests clearly differentiate between the normal and perceptually impaired groups. In addition, the three tests correlate with each other at a statistically significant level.

Clinical comparison of the visual parameters in infants with intrauterine growth retardation vs. infants with normal birth weight.

We measured vision function in a number of 7-month-old infants with intrauterine growth retardation (IUGR) and compared these findings to those for 7-month-old infants of normal birth weight. The IUGR infants had an average visual acuity of 6/162 (20/540) and an average spherical refractive error of 1.49 D hyperopia. The normal birth weight infants had an average visual acuity of 6/118.8 (20/396) and an average spherical refractive error of 0.94 D hyperopia. However, the differences between the infant groups for visual acuity and refractive error were not statistically significant. Anisometropia, astigmatism, and strabismus were infrequent for both infant groups. The results of this study suggest that IUGR infants have visual abilities resembling those of normal birth weight infants.

Norms for hand-held rotary prism vergences.

Norms of clinically useful techniques provide a means to measure and compare patient performance against a large clinical population of asymptomatic subjects. This study establishes mean values for vergence ranges (break and recovery) at 6 m and 40 cm using hand-held rotary prisms. Secondary effects of eye preference (dominance), order of prism presentation, and differences of results between clinicians were evaluated and found to have no statistical significance. This is another example of the trend to establish normal values for functions routinely measured in the optometric examination. Values are now available for the most commonly used vergence testing methods: the binocular rotary prism in the phoropter, the prism bar, and the handheld rotary prism. Testing can now be accomplished with or without a phoropter and comparisons can be made to normal values.

Use of light intensity reduction for amblyopia therapy.

A form of amblyopia therapy is presented using light intensity reduction which provides a means of increasing the visual acuity in the amblyopic eye while preserving and promoting binocularity. In addition to the rationale and specific instructions for therapy, an illustrative case is presented of a 7-year-old boy with anisometropic amblyopia and eccentric fixation who was treated with light intensity reduction produced by Polaroid filters before his nonamblyopic eye. In this case acuity improved from 6/30 (20/100) to 6/7.8 (20/26), fixation improved from 2 degrees eccentric to unsteady central, and stereopsis increased from no measurable amount to 140 sec as measured by the Randot stereotest.

Normalization of prism bar vergences.

Normal values for asymmetric prism bar vergences were derived from the clinic population of the School of Optometry, University of Alabama in Birmingham. The means, standard deviations, effect of order of prism presentation, and eye dominance were examined for three clinical groups. The results provide standards for prism bar vergence and demonstrate that order of testing and dominance have no significant effect upon the values obtained.

Temporal contrast sensitivity in amblyopia.

Temporal contrast sensitivity functions were determined for the normal (20/20) and amblyopic eyes of five strabismic and/or anisometropic amblyopes and for both eyes of two nonamblyopes. In deep amblyopia (20/100+), contrast sensitivity was reduced at all temporal frequencies in the amblyopic eye, whereas no deficit was observed for subjects whose acuity was 20/40 or better. This result indicates that reduced temporal sensitivity is a significant component of strabismic and anisometropic amblyopia.