Sex Hormones Influence the Helmholtz-Kohlrausch Effect.

Purpose: Saturated lights appear brighter than white lights of the same luminance. This is the Helmholtz-Kohlrausch (H-K) effect, and the phenomenon can be estimated by modeling achromatic luminance and saturation to total brightness. Current H-K effect models are different between women and men and are also more variable in women, which may be due to hormonal changes across the menstrual cycle (MC).

The Effects of Sex, Oral Contraception, and Menstrual Cycle Phase on Intraocular Pressure, Central Corneal Thickness, and Foveal Thickness: A Descriptive Analysis.

The primary goal of this study was to investigate the effects of sex, oral contraceptive (OC) use, and menstrual cycle phase on common ocular parameters assessed during ophthalmic evaluations, namely intraocular pressure (IOP), central corneal thickness (CCT), and foveal thickness (FT), in young healthy adults. We measured IOP, CCT, and FT in 60 participants (16 men, 16 contraceptive users, and 28 cycling women) over two sessions that characterized the menstrual cycle phase in women. For men in our study, two sessions were separated by two weeks.

Macular pigment optical density and visual quality of life.

Purpose: There is robust evidence that higher macular pigment concentrations help reduce both veiling and discomfort glare in patients with or without ocular disease. We investigated whether there was also a relationship between macular pigment optical density (MPOD) and patient surveys about glare or ocular discomfort.

Methods: We measured MPOD psychophysically in 23 healthy subjects and administered the National Eye Institute Visual Functioning Questionnaire (VFQ-25).

Effects of Oral Antihistamines on Tear Volume, Tear Stability, and Intraocular Pressure.

The goal of this study was to investigate the effects of two commonly used oral antihistamines-diphenhydramine and loratadine-on tear volume, tear breakup time, and intraocular pressure. Placebo, diphenhydramine, and loratadine were administered for one week to 33 subjects experimentally blind to the treatment given. All the subjects received all three treatments over a period of six weeks.

Is the Helmholtz-Kohlrausch Effect More Robust in Women?

For gray or achromatic objects, brightness is a relatively simple transformation where very low luminance levels are perceived as black and higher levels are perceived as white. For chromatic objects, the transformation is more complex, depending on color purity as well. This influence of color purity on a color's perceived brightness is a well-established phenomenon known as the Helmholtz-Kohlrausch (H-K) effect.

The Dominant Eye: Dominant for Parvo- But Not for Magno-Biased Stimuli?

Eye dominance is often defined as a preference for the visual input of one eye to the other. Implicit in this definition is the dominant eye has better visual function. Several studies have investigated the effect of visual direction or defocus on ocular dominance, but there is less evidence connecting ocular dominance and monocular visual thresholds.

Macular Pigment and Visual Performance in Low-Light Conditions.

Purpose: By reducing rod intrusion and improving efficiency of neural signaling throughout the visual system, macular pigment (MP) could improve many aspects of visual performance in low-light level conditions. Our study examined this possibility for a variety of visual performance parameters, including spatial resolution, dark adaptation kinetics, and color detection.

Methods: Twenty-seven subjects participated in the study.

An atypical presentation of visual conversion disorder.

Nonorganic vision loss accounts for up to 5% of patients and presents in two forms, malingering and visual conversion disorder (VCD). It is described a case of VCD in a new mother struggling both with her husband being deployed overseas and the recent death of her father. In addition, she had been evaluated for a concussion secondary to a motor vehicle accident three months prior.

Depression and burnout symptoms among Air Force family medicine providers.

This study investigated the prevalence of depression and burnout symptoms among family medicine providers on active duty in the US Air Force. Results demonstrated that 84% of those surveyed scored positive for degrees of depression symptoms; only sex differences were significant.

Visual disruption using the thermal lensing effect in the human eye: pilot study.

At select wavelengths, near infrared (IR) light is absorbed in the preretinal media of the eye. This produces small transient increases in temperature that temporarily alter the local index of refraction. If the IR exposure is sufficiently high, a momentary reduction in the focusing power of the eye can be induced through an effect known as thermal lensing.

Macular pigment and visual performance in glare: benefits for photostress recovery, disability glare, and visual discomfort.

Purpose: One theory of macular pigment's (MP) presence in the fovea is to improve visual performance in glare. This study sought to determine the effect of MP level on three aspects of visual performance in glare: photostress recovery, disability glare, and visual discomfort.

Methods: Twenty-six subjects participated in the study.