New photographic techniques for clinical evaluation of acne

Quantitative measurement of skin surface oiliness and shine using differential polarized images

Excess amounts of skin surface oil can lead to adverse psychological consequences. Grease-spot photometry-based techniques measure sebum production rate. However, besides being tedious, these measurements are influenced by contact area, applied pressure, and time of application. Image analysis of polarized images has the potential to provide objective, quantitative information of skin oiliness. This study was designed to set up an imaging device for capturing and enhancing the changes in skin surface oiliness and to clinically and quantitatively, (via image analysis), evaluate varying levels of skin surface oiliness. Mineral oil was used to simulate skin surface oil. 40.5 µL of the mineral oil was applied within a two inch square area of interest on facial skin in twelve steps, from 1 to 40.5 µL, at 40% increments. The results indicate a strong correlation between the quantitative skin surface oiliness measurements and the clinical assessments. This sensitive technique has the potential to be utilized in future studies to evaluate product efficacies in reducing skin oiliness.

Use of Crossed Polarizers to Enhance Images of the Eyelids

PURPOSE

To describe imaging of the external eye with Crossed Polarizers to enhance clinically important features in digital photographs of the eyelids.

METHODS

External photographs with and without crossed polarizing filters were taken of patients with blepharitis and controls with no clinical eye pathology.

RESULTS

Photographing eyelid skin through Crossed Polarizers decreased reflections on the skin surface and improved visualization of eyelid telangiectasias and blood vessels in patients with a broad range of skin pigmentation and ethnicities.

CONCLUSIONS

The use of Crossed Polarizers in imaging the external eye reduces reflections and glare from the eyelid skin and margins, thereby allowing for a more detailed evaluation of underlying structures and analysis of images. These findings suggest that including Crossed Polarizers in clinical photography has informative applications for assessing eyelid disease.

Fluorescent image analysis for evaluating the condition of facial sebaceous follicles

BACKGROUND/PURPOSE

Conventional methods, such as 'Sebutape' and 'Sebumeter,' can provide quantitative information on sebum excretion but cannot reflect the condition of sebaceous follicles that can be indirectly evaluated with fluorescent colors of sebum. The images of sebum excretion can be obtained with an ultraviolet-A light that is generally called 'Wood's Lamp.' In this study, we describe fluorescent image analysis methods for the detection of sebum and the color segmentation of sebum to evaluate the condition of sebaceous follicles.

METHODS/RESULTS

For subject-dependent automatic image analysis, we extracted calibrated image analysis methods that were optimized for digital fluorescent images acquired from our imaging system. The calibrated subjective threshold values for sebum detection were determined by statistically analyzing the number of sebum detected by the automatic threshold value method and the subjective threshold value method (R=0.947, the number of volunteers: 29). In fluorescent color analysis of sebum, the calibrated reference color markers for the red and white colors were extracted with a coefficient of variance of <10%.

CONCLUSION

We are confident that such calibrated image analysis methods in combination with our imaging system can provide useful quantitative diagnostic information for sebum-related skin pathologies.

Digital camera images obtained using a light-emitting diode illuminator and their dermatological applications

BACKGROUND/PURPOSE

Although digital cameras have powerful macrocapabilities, flash macrophotographs are often unsatisfactory. The aim of this study was to develop a light-emitting diode (LED) illuminator for macro digital photography that allows colorimetric investigations of the skin.

METHODS

We devised an LED illuminator suitable for acquiring super-macro digital images of the skin. Reference CIELAB color chart values were compared statistically with computed values from digital images in order to obtain equations for real CIELAB values. Using these, we acquired and analyzed images of various dermatological conditions using an LED illuminator.

RESULTS

The images obtained with the devised LED illuminator were more reproducible than flash-assisted photographs. With proper camera settings, the devised LED illuminator and the color analysis method developed during this study provided digital skin images containing colorimetric information.

CONCLUSION

A digital camera equipped with an LED illuminator is a useful tool for dermatological research and clinical practice.