David A. Goss

Clinical accommodation and heterophoria findings preceding juvenile onset of myopia.

This study was performed to test the hypothesis that accommodation and convergence differences precede the onset of myopia in children. Records of children who were emmetropic and became myopic (became myopic group) and children who remained emmetropic (remained emmetropic group) were collected from seven private optometry practices. The practices were located in Illinois, Iowa, Oklahoma, and Oregon. Nearpoint phorias and positive relative accommodation (PRA) findings were significantly different in the two groups by t-test. Negative relative accommodation (NRA) did not show a statistically significant difference in the two groups. Binocular cross-cylinder findings were shown by analysis of variance (ANOVA) to be significantly affected by group (became myopic vs. remained emmetropic) and by practice location. These results support the hypothesis that differences in accommodation and convergence function may be precursors of juvenile onset myopia.

Rates of childhood myopia progression with bifocals as a function of nearpoint phoria : consistency of three studies

Three studies on the effect of bifocal lenses on childhood myopia progression are discussed and re-analyzed. In all three, the rates of progression were less with bifocals than with single-vision lenses in esophoria. Rates with the two types of correction were similar in patients who had nearpoint orthophoria or exophoria.

Reliability of and comparisons among three variations of the alternating cover test.

One of the most commonly used methods for measuring heterophoria is the alternating cover test. Differences in specific procedures and observational criteria used by examiners may result in different measurements of heterophoria on the same patient. This study evaluated the inter‐examiner reliability of three different cover test techniques: the estimated cover test, the prism neutralized objective cover test, and the prism neutralized subjective cover test. Two examiners performed each technique on each of 72 subjects. Reliability was assessed using correlational methods and mean difference calculations. Although there were some inter‐examiner differences for the different techniques, all of these differences were within previously determined minimum detectable eye movement ranges. Therefore, when used by experienced clinicians, each of these techniques appears to be a reliable method of heterophoria determination, and their results are comparable.

Reliability of the response AC/A ratio determined using nearpoint autorefraction and simultaneous heterophoria measurement

Background: Clinicians frequently assess the accommodative convergence to accommodation (AC/A) ratio using near phoria measurements and accommodative stimuli. The purpose of this study was to evaluate the repeatability of AC/A ratio measurements and to compare the response AC/A ratio to stimulus AC/A ratios determined two different ways.

Accommodative response under monocular and binocular conditions as a function of phoria in symptomatic and asymptomatic subjects.

The neurological linkage of vergence and accommodation is a factor which can affect accuracy of accommodation, is in turn associated with symptoms of near‐related visual discomfort. The purpose of this study was to compare the accommodative response under monocular and binocular conditions in symptomatic and asymptomatic participants with different near phorias.

Comparison of four different binocular balancing techniques

Several techniques of balancing have been proposed for the equalisation of the accommodative state between the two eyes. This study was designed to compare the results of different balancing techniques.

The Axial Length/Corneal Radius Ratio in Emmetropia and Ametropia: A Review

The ratio of axial length to corneal radius (AL/CR ratio) has a value of approximately 3.0 in emmetropia eyes, 3.0 in myopic eyes. There is evidence that in emmetropic children an AL/CR ratio greater than 3.0 indicates a risk for the development of myopia. In adult eyes, variance in the AL/CR ratio has been shown to account for as much as 93% of the variance in the eye’s refractive state. The results of 3 cross-sectional studies show that the AL/CR ratio, in emmetropic or near-emmetropic eyes, is remarkably stable with age.