Maximum angle of ocular duction during visual fixation as a function of age.

PURPOSE: To measure and compare the maximum angle of ocular duction in healthy individuals as a function of age. METHODS: A calibrated arc perimeter was modified to display one of six randomly presented targets (high contrast Snellen equivalent letters), in both vertical (supra/infraduction) and horizontal (ab/adduction) gaze to the dominant eye of 204 healthy volunteers with best-corrected visual acuity. A bite-bar and headrest were employed to prevent head movement. Using a modified method of limits for discrimination threshold, a maximum mean angle of ocular duction was determined by stepping a target out in 5 degrees steps until an error was reported and thereafter bracketing around the limits of the target identification in 1 degrees steps. A mean threshold value was determined as the angle at which a subject obtained a correct response 75% of the time in two and as many as the trails in each of the four randomly presented directions of gaze (abduction, adduction, supraduction and infraduction). RESULTS: A decrease in mean maximum duction angle was found over all age groups in al four directions (p < 0.001), with a step decline beginning in the sixth decade and almost doubling in the oldest age group tested (80-95 years-olds). The percent change in mean maximum angle of duction due to age from the 14-19 to the 80-95 year-olds was: abduction 21%, adduction 24%, supraduction 35%, infraduction 26%. CONCLUSION: Baseline data are useful to differentiate normal changes occurring with age from early signs of disease. AdditIonally, disease progression and effects of treatment can be monitored.

Visual motion detection in patients with absent vestibular function.

Labyrinthine defective subjects (LDS) experience oscillopsia during head movements due to the absence of the vestibulo-ocular reflex (VOR). The purpose of this study was to compare horizontal and vertical visual motion detection in LDS during (i) body-stationary and (ii) horizontal whole-body oscillation conditions. Twelve LDS and controls detected the onset of drift direction of a grating that moved with accelerating velocity. Thresholds were raised in the patient group in both conditions. The loss of the VOR per se cannot explain raised thresholds in the body-stationary condition nor during whole-body (horizontal) oscillation with vertical grating motion. Findings indicate changes in visual processing that make LDS less sensitive to visual motion. It is postulated that these changes are due to adaptive mechanisms involved to reduce oscillopsia.

A study of pre-school vision screening tests' testability, validity and duration: do group differences matter?

Vision screening was performed on 268 pre-school children: 170 from a private pre-school, 33 from a Caribbean-American parochial pre-school and 65 pre-school children from a clinic serving indigent Spanish farm-workers. Using a multi-station format, a stereoacuity test and two visual acuity tests were performed during a single screening session. The time it took to complete a test was recorded. To pass the screening, children were required to pass one visual acuity test and the stereoacuity test. Children who could not complete the protocol were retested at a later date. Children who failed the screening and every fourth child who passed the screening were referred for a full eye examination. The parents and teachers were masked to the results of the screening as well as the optometrists who performed the eye examination. Sensitivity, specificity and accuracy scores were 100%, 79% and 80%, respectively. Three-year-old children completed the Lea Symbol Chart more often than the HOTV. No differences in time required to complete a visual acuity test were found. The Lea Symbol chart is more likely to be completed by young children. Testability changes significantly with age rather than with the instrument when socio-ethnic factors are held constant. Differences among groups and the sensitivity of the screening are discussed.

Effect of osteopathy in the cranial field on visual function--a pilot study.

CONTEXT: The effects of osteopathy in the cranial field on visual function-particularly on changes in the visual field and on the binocular alignment of the eyes-have been poorly characterized in the literature. The authors examined whether osteopathy in the cranial field resulted in an immediate, measurable change in visual function among a sample of adults with cranial asymmetry. STUDY DESIGN: Randomized controlled double-blinded pilot clinical trial. SUBJECTS: Adult volunteers between ages 18 and 35 years who were free of strabismus or active ocular or systemic disease were recruited. Inclusion criteria were refractive error ranging between six diopters of myopia and five diopters of hyperopia, regular astigmatism of any amount, and cranial somatic dysfunction. INTERVENTION: All subjects were randomly assigned to the treatment or control group. The treatment group received a single intervention of osteopathy in the cranial field to correct cranial dysfunction. The control group received light pressure of a few ounces of force applied to the cranium without osteopathic manipulative treatment. MEASUREMENTS: Preintervention and postintervention optometric examinations consisted of distant visual acuity testing, Donder push-up (ie, accommodative system) testing, local stereoacuity testing, pupillary size measurements, and vergence system (ie, cover test with prism neutralization, near point of convergence) testing. Global stereoacuity testing and retinoscopy were performed only in preintervention to determine whether subjects met inclusion criteria. Analysis of variance (ANOVA) was performed for all ocular measures. RESULTS: Twenty-nine subjects completed the trial-15 in the treatment group and 14 in the control group. A hierarchical ANOVA revealed statistically significant effects within the treatment group and within the control group (P <.05) in distance visual acuity of the right eye (OD) and left eye (OS), local stereoacuity, pupillary size measured under dim illumination OD and OS, and near point of convergence break and recovery. For the treatment group vs the control group, a statistically significant effect was observed in pupillary size measured under bright illumination OS (P <.05). CONCLUSIONS: The present study suggests that osteopathy in the cranial field may result in beneficial effects on visual function in adults with cranial asymmetry. However, this finding requires additional investigation with a larger sample size and longer intervention and follow-up periods. (ClinicalTrials.gov number NCT00510562).

Topographical analysis of the optic nerve in migraine patients.

PURPOSE: Vascular dysfunction appears related to the development of migraines and has been associated with pressure-independent glaucoma. The purpose of this study is to investigate possible topographical differences in the optic nerve between migraine sufferers and normal age-matched control subjects. The identification of optic disc topographical differences between migraine and non-migraine sufferers may help clinicians determine if the presence of migraine influences the development and progression of glaucoma. METHODS: Sixty consecutively seen patient-volunteers (30 subjects in migraine group: mean age 37.7 years, range from 19 to 66 years, 28 females and 2 males; 30 subjects in the control group: mean age 37.6 years, range from 19 to 61 years, 29 females and 1 male) were categorized as either migraine patients or control group subjects. All migraine subjects had been medically diagnosed with a migraine syndrome and were being treated with prophylactic medication. Optic nerve head topographical analysis was performed using a confocal scanning laser ophthalmoscope. The data was evaluated using generalized estimating equations, a priori and post hoc power analysis. RESULTS: No significant differences were found in any of the optic nerve parameters examined between the two groups. CONCLUSIONS: This study indicates that the optic nerve parameters as measured by the Heidelberg retinal tomograph II do not differ between migraine sufferers and age-matched control subjects.