Dopaminergic agonists that result in ocular growth inhibition also elicit transient increases in choroidal thickness in chicks.

The dopaminergic system has been implicated in ocular growth regulation in chicks and monkeys. In both, dopamine D2 agonists inhibit the development of myopia in response to form deprivation, and in chicks, to negative lenses as well. Because there is mounting evidence that the choroidal response to defocus plays a role in ocular growth regulation, we asked whether the effective agonists also elicit transient thickening of the choroid concomitant with the growth inhibition.

Ocular wavefront aberrations in the common marmoset Callithrix jacchus: effects of age and refractive error.

The common marmoset, Callithrix jacchus, is a primate model for emmetropization studies. The refractive development of the marmoset eye depends on visual experience, so knowledge of the optical quality of the eye is valuable. We report on the wavefront aberrations of the marmoset eye, measured with a clinical Hartmann-Shack aberrometer (COAS, AMO Wavefront Sciences).

Optic neuropathy in a child with alopecia.

A 4-year-old boy develops an insidious optic neuropathy, of unknown etiology, followed shortly thereafter by a focal patch of hair loss (biopsy proven-alopecia areata) on the back of his head. The temporal aspects of these findings suggest a common, likely inflammatory, etiology.

Inhibiting the neuronal isoform of nitric oxide synthase has similar effects on the compensatory choroidal and axial responses to myopic defocus in chicks as does the non-specific inhibitor L-NAME.

In birds, the choroid plays a role in the visual regulation of eye growth, thickening in response to myopic defocus, and thinning in response to hyperopic defocus, in both cases moving the retina towards the image plane. This response is rapid, occurring within hours of the defocus stimulus. These changes are consistently associated with slower changes in the sclera, that result in the appropriate changes in axial elongation, decreasing growth in response to myopic defocus and increasing it in response to hyperopic defocus.

Treatment options for myopia.

Myopia is a significant public health problem and its prevalence may be increasing over time. The main treatment options of single vision spectacle lenses, contact lenses, and refractive surgery do not slow the accompanying eye growth or retard the physiological changes associated with excessive axial elongation. High myopia is a predisposing factor for retinal detachment, myopic retinopathy, and glaucoma, contributing to loss of vision and blindness.

History of community health center affiliations with The New England College of Optometry.

Background: Since the 1970s, The New England College of Optometry (NECO) has been a leader in community-based educational programming. This was accomplished through the development of affiliation agreements with health care facilities that care for the underserved, notably community health centers (CHCs). The college's clinical system, the New England Eye Institute (NEEI), develops CHC programs, manages professional services agreements, initiates teaching affiliation agreements, and leads staff recruitment and retention efforts.

Transient increases in choroidal thickness are consistently associated with brief daily visual stimuli that inhibit ocular growth in chicks.

In chickens, transient changes in choroidal thickness are found in conditions in which the eye is slowing its growth in response to visual episodes that prevent excessive elongation. To test the hypothesis that the choroidal and ocular growth responses are linked, we used a variety of "brief daily" stimuli known to ameliorate the development of myopia and assessed the concurrence of the responses. If the hypothesis is true, they should always be correlated.

Accommodation and induced myopia in marmosets.

Accommodation may indirectly influence visually guided eye growth by affecting the retinal defocus signal used to guide growth. Specifically, increased lags of accommodation associated with low stimulus-response (S-R) function slopes will impose increased hyperopic blur on the retina and may induce axial elongation and myopia. The purpose of this study was (1) to measure accommodation in awake, free viewing marmosets and (2) compare accommodation behavior in marmosets before and after inducing different amounts of myopia with binocular spectacle lenses.

Principles and designs of the iseikonic lenses for near vision.

Purpose: The purposes of this study were to find the problems of afocal iseikonic lenses as used for near vision and to elaborate the principles and designs of the ideal near iseikonic lenses.

Methods: By analyzing the image-object relationship and imaging processes, the formulae were derived to quantitatively and qualitatively describe two errors of afocal iseikonic lenses as used for near vision: 1) inequality of accommodative demands to both eyes and 2) the difference between the actual and the nominal magnification. Formulae were derived to calculate and design the ideal near iseikonic lenses.

Comparison of the experience sampling method and questionnaires to assess visual activities in pre-teen and adolescent children.

Aim: A study was conducted to assess the feasibility of the experience sampling method (ESM) to quantify the daily visual tasks of children.

Methods: Thirty-one children (9-14 years old, 39% male) were randomly paged after school (four times per day) and on weekends (eight times per day) for seven consecutive days. When paged, the children completed a voicemail survey regarding the nature, duration, working distance and type of visual correction worn during the activity.

The autonomic facial nerve pathway in birds: a tracing study in chickens.

Purpose: In birds, the parasympathetic innervation of the choroid is via the ciliary (cranial nerve III) and pterygopalatine (cranial nerve VII) ganglia, the latter consisting of a chain of microganglia within the orbit. Because of the scattered nature of these microganglia, lesions of this nerve pathway in birds have not been attempted, making interpretation of the functional contribution of this parasympathetic input to the avian eye uncertain. The purpose of this study was to find an extraorbital approach to the preganglionic part of cranial nerve VII and to reveal its peripheral terminals and its site of origin in the brain stem.

Change in the synthesis rates of ocular retinoic acid and scleral glycosaminoglycan during experimentally altered eye growth in marmosets.

Purpose: The purpose of this study was to examine the possibility that all-trans-retinoic acid (RA) in the eye is a signal related to changes in scleral extracellular matrix in a primate model of postnatal eye growth.

Methods: Juvenile marmosets (Callithrix jacchus) were divided into two experimental groups based on their response to monocular deprivation with diffusers: group 1, treated eyes becoming longer than fellow control eyes (n = 8), and group 2, treated eyes becoming shorter than control eyes (n = 7). Eyes were enucleated, dissected, and assayed for changes in the rates of scleral glycosaminoglycan (GAG) synthesis and ocular RA synthesis.

Inhibiting the transient choroidal thickening response using the nitric oxide synthase inhibitor l-NAME prevents the ameliorative effects of visual experience on ocular growth in two different visual paradigms.

It is generally accepted that the increase in choroidal thickness in response to myopic defocus in chicks acts to move the retina towards the image plane. It may also constitute part of the signal cascade in the visual regulation of eye growth. To test this, we used the nitric oxide synthase inhibitor l-NAME to inhibit the defocus induced choroidal thickening under two different visual conditions, and looked at the effects on ocular growth rate.

Characteristics of accommodative behavior during sustained reading in emmetropes and myopes.

Accommodation has long been suspected to be involved in the development of myopia because near work, particularly reading, is known to be a risk factor. In this study, we measured several dynamic characteristics of accommodative behavior during extended periods of reading under close-to-natural conditions in 20 young emmetropic and stable myopic subjects. Accommodative responses, errors, and variability (including power spectrum analysis) were analyzed and related to accommodative demand and subject refractive error.

The phase relationships between the diurnal rhythms in axial length and choroidal thickness and the association with ocular growth rate in chicks.

Eyes of young chickens show diurnal oscillations in axial length and choroidal thickness that are out of phase. In eyes responding to myopic defocus induced by prior form deprivation, the two rhythms shift into phase. In order to elucidate the possible role for these rhythms in ocular growth regulation, they were measured under visual conditions that altered ocular growth rate.

Ocular involvement in patients infected by the West Nile virus.

West Nile virus (WNV), a mosquito-borne RNA virus for which there is no treatment, began emerging as a threat to health in the United States in 1999. Since then, its frequency and apparent clinical severity have increased. Patients with severe disease may experience ocular complications that include pain, vitreous inflammation, nonrelapsing chorioretinitis, retinal vasculitis, chorioretinal scarring, optic neuritis, and retinal hemorrhages.

Temporal integration characteristics of the axial and choroidal responses to myopic defocus induced by prior form deprivation versus positive spectacle lens wear in chickens.

Purpose: In chicks, the temporal response characteristics to form deprivation and to spectacle lens wear (myopic and hyperopic defocus) show essential differences, suggesting that the emmetropization system "weights" the visual signals differently. To further explore how the eye integrates opposing visual signals, we examined the responses to myopic defocus induced by prior form deprivation vs. that induced by positive spectacle lenses, in both cases alternating with form deprivation.

Accommodation, accommodative convergence, and response AC/A ratios before and at the onset of myopia in children.

Purpose: The purpose of this study was to investigate accommodation, accommodative convergence, and AC/A ratios before and at the onset of myopia in children.

Methods: Refractive error, accommodation, and phorias were measured annually over a period of 3 years in 80 6- to 18-year-old children (mean age at first visit = 11.1 years), including 26 who acquired myopia of at least -0.

Increased accommodation following adaptation to image blur in myopes.

Prolonged exposure to blurred images produces perceptual adaptation (M. A. Webster, M.

Use of the experience sampling method to measure nearwork.

Purpose: The purpose of this study was to use the Experience Sampling Method (ESM) to evaluate the daily visual activities of a group of optometry students and to determine whether the ESM could detect differences in visual activities when a difference was thought to exist.

Methods: Sixty-two optometry students, at four different levels of training, at The Ohio State University College of Optometry were tested using the ESM during a 14-day period. A subgroup of 18 subjects in their fourth year of study was asked to repeat the 14-day ESM on a second occasion.

A survey of clinical prescribing philosophies for hyperopia.

Background: Prescribing philosophies for hyperopic refractive error in symptom-free children vary widely because relatively little information is available regarding the natural history of hyperopic refractive error in children and because accommodation and binocular function closely related to hyperopic refractive error vary widely among children. We surveyed pediatric optometrists and ophthalmologists to evaluate typical prescribing philosophies for hyperopia.

Methods: Practitioners were selected from the American Academy of Optometry Binocular Vision, Perception, and Pediatric Optometry Section; the College of Vision Development; the pediatric and binocular vision faculty members of the colleges of optometry; and the American Association for Pediatric Ophthalmology and Strabismus.

An evaluation of pupil size standards used by police officers for detecting drug impairment.

Background: The Drug Evaluation and Classification (DEC) program was developed to detect, arrest, and convict drivers impaired by drugs other than alcohol. The DEC program is a training program designed to prepare police officers and other qualified persons to serve as Drug Recognition Experts (DREs).

Purpose: The purposes of this study were: (1) to determine normative values and ranges for pupillary responses using the specific DEC program protocols for pupil testing in nonimpaired persons, and (2) to appraise the suitability of the 3.

Comparison of spherical equivalent refraction and astigmatism measured with three different models of autorefractors.

Purpose: The purpose of this study was to compare refractions measured with three different autorefractors.

Methods: The refractive error of each eye of 50 adults aged 17 to 59 years (mean, 30.5 years) was measured without cycloplegia using the Canon R-1 and two newer instruments, the Grand Seiko WR-5100K and the Nidek ARK 700-A.

Overnight orthokeratology: preliminary results of the Lenses and Overnight Orthokeratology (LOOK) study.

Background: The Lenses and Overnight Orthokeratology (LOOK) study is a pilot study designed to learn the procedures of orthokeratology lens fitting in preparation for a planned larger clinical trial and to obtain data with which to calculate a sample size for that larger study. Data are presented for the first 3 months of the LOOK study.

Methods: Sixty subjects were enrolled in this multicenter pilot study to evaluate the success and safety of treatment with overnight orthokeratology contact lenses.

Clinical quality assessment using computer monitor photoimages of optic nerve head cupping.

Background: Photo documentation (color slides) of abnormal optic nerve heads enable the clinician to accurately access or estimate the percentage of the optic nerve cupping to quantify the progression of glaucoma. The purpose of this study is to compare cupping estimations using digital images on a computer monitor to those using standard color slides.

Methods: Ten sets of stereo optic nerve head photos from six glaucoma suspects were used in this study.