Assessing Binocular Interaction in Amblyopia and Its Clinical Feasibility

Purpose To measure binocular interaction in amblyopes using a rapid and patient-friendly computer-based method, and to test the feasibility of the assessment in the clinic. Methods: Binocular interaction was assessed in subjects with strabismic amblyopia (n = 7), anisometropic amblyopia (n = 6), strabismus without amblyopia (n = 15) and normal vision (n = 40). Binocular interaction was measured with a dichoptic phase matching task in which subjects matched the position of a binocular probe to the cyclopean perceived phase of a dichoptic pair of gratings whose contrast ratios were systematically varied. The resulting effective contrast ratio of the weak eye was taken as an indicator of interocular imbalance. Testing was performed in an ophthalmology clinic under 8 mins. We examined the relationships between our binocular interaction measure and standard clinical measures indicating abnormal binocularity such as interocular acuity difference and stereoacuity. The test-retest reliability of the testing method was also evaluated. Results: Compared to normally-sighted controls, amblyopes exhibited significantly reduced effective contrast (∼20%) of the weak eye, suggesting a higher contrast requirement for the amblyopic eye compared to the fellow eye. We found that the effective contrast ratio of the weak eye covaried with standard clincal measures of binocular vision. Our results showed that there was a high correlation between the 1st and 2nd measurements (r = 0.94, p<0.001) but without any significant bias between the two. Conclusions: Our findings demonstrate that abnormal binocular interaction can be reliably captured by measuring the effective contrast ratio of the weak eye and quantitative assessment of binocular interaction is a quick and simple test that can be performed in the clinic. We believe that reliable and timely assessment of deficits in a binocular interaction may improve detection and treatment of amblyopia

Quantum Dot Light Enhancement Substrate for OLED Solid-State Lighting

With DOE Award No. DE-EE00000628, QD Vision developed and demonstrated a cost-competitive solution for increasing the light extraction efficiency of OLEDs with efficient and stable color rendering index (CRI) for solid state lighting (SSL). Solution processable quantum dot (QD) films were integrated into OLED ITO-glass substrates to generate tunable white emission from blue emitting OLED) devices as well as outcouple light from the ITO film. This QD light-enhancement substrate (QD-LED) technology demonstrated a 60% increase in OLED forward light out-coupling, a value which increases to 76% when considering total increase in multi-directional light output. The objective for the first year was an 80% increase in light output. This project seeks to develop and demonstrate a cost-competitive solution for realizing increased extraction efficiency organic light emitting devices (OLEDs) with efficient and stable color rendering index (CRI) for SSL. Solution processible quantum dot (QD) films will be utilized to generate tunable white emission from blue emitting phosphorescent OLED (Ph-OLED) devices

Quantum Dot Light Enhancement Substrate for OLED Solid-State Lighting

With DOE Award No. DE-EE00000628, QD Vision developed and demonstrated a cost-competitive solution for increasing the light extraction efficiency of OLEDs with efficient and stable color rendering index (CRI) for solid state lighting (SSL). Solution processable quantum dot (QD) films were integrated into OLED ITO-glass substrates to generate tunable white emission from blue emitting OLED) devices as well as outcouple light from the ITO film. This QD light-enhancement substrate (QD-LED) technology demonstrated a 60% increase in OLED forward light out-coupling, a value which increases to 76% when considering total increase in multi-directional light output. The objective for the first year was an 80% increase in light output. This project seeks to develop and demonstrate a cost-competitive solution for realizing increased extraction efficiency organic light emitting devices (OLEDs) with efficient and stable color rendering index (CRI) for SSL. Solution processible quantum dot (QD) films will be utilized to generate tunable white emission from blue emitting phosphorescent OLED (Ph-OLED) devices

Examples of individual subject data.

<p>Each panel contains the perceived phase versus interocular contrast ratio function (red circles) of a representative subject from each group. Subject's age, angular eye deviation (type and amount of deviation), fixational information (fuses, left or right eye) and visual acuity are also shown in each panel. The data were fitted with the attenuation model (Eq. 4) to estimate effective contrast ratio (ECR) of the weak eye. The black solid lines are the best fits of the model. The dotted arrow lines (magenta color) indicate estimated effective contrast ratios. Shaded areas represent ±1 Standard Error of the Mean (SEM) of the fits. The goodness-of-fit was assessed with the <i>r²</i> statistic. (<b>a</b>) An individual with strabismic amblyopia (8 yrs, ET 6Δ, Fuses); (<b>b</b>) An individual with anisometropic amblyopia (9 yrs, ortho); (<b>c</b>) An individual with strabismus (7 yrs, XT 20Δ, Fuses); (<b>d</b>) A normally-sighted individual (7 yrs, ortho); (<b>e</b>) A normally-sighted individual (6 yrs, ortho); (<b>f</b>) A normally-sighted individual (5 yrs, ortho); (<b>g</b>) Correlation between effective contrast ratio and age (year). *ET: Esotropia, XT: Exotropia, Δ: Prism diopter, FU: Fuses, OD: Right eye, OS: Left eye. Note that the reported ocular deviation and fixational information are those made at near fixation (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100156#pone.0100156.s001" target="_blank">Figs S1</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100156#pone.0100156.s002" target="_blank">S2</a> for the data from all individual subjects).</p

Relationships between effective contrast ratio and clinical binocular function measures.

<p>(<b>a</b>) Mean effective contrast ratios for four levels of IAD in logMAR units; (<b>b</b>) Mean effective contrast ratios for four levels of stereoacuity in acrsec units. Error bars represent ±1 SEM.</p

Subject characteristics.

<p>Note that stereoacuity 900″ is a surrogate for zero stereoacuity for the purpose of computation. SD: Standard deviation, ET: Esotropia, XT: Exotropia, INT: Intermittent, AC: Accommodative, ALT: Alternator, FU: Fuses, Δ: Prism diopter, OD: Right eye, OS: Left eye. Also note that the reported information about ocular deviation and fixational eye are those made at near fixation (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100156#pone.0100156.s001" target="_blank">Figs S1</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100156#pone.0100156.s002" target="_blank">S2</a> for the data from all individual subjects).</p

Mean effective contrast ratio (<i>η</i>), mean parameter value <i>γ</i> and mean <i>r</i>² value for the four subject groups.

<p>The number in parenthesis indicates ±1 Standard Errors of the Mean (SEM).</p