[Blue light and intraocular lenses (IOLs): Beliefs and realities]

The first intraocular lenses (IOLs) used for cataract surgery transmitted both ultraviolet (UV) radiation and visible light to the retina. Colorless UV-blocking IOLs were introduced and rapidly adopted in the 1980s. Yellow-tinted blue-blocking (also known as blue-filtering) IOLs were marketed in the early 1990s. Blue-blocking IOLs were intended to simulate age-related crystalline lens yellowing to reduce the cyanopsia that some patients experienced after cataract surgery. When blue-filtering IOLs were introduced in North America, however, blue-blocking chromophores were advocated as a way to protect patients from age-related macular degeneration (AMD) despite the lack of evidence that normal environmental light exposure causes AMD. The "blue light hazard" is a term that describes the experimental finding that acute, abnormally intense light exposures are potentially more phototoxic to the retina when short rather than long wavelengths are used. Thus, in brief exposures to intense light sources such as welding arcs, ultraviolet radiation is more hazardous than blue light, which is more hazardous than longer wavelength green or red light. International commissions have cautioned that the blue light hazard does not apply to normal indoor or outdoor light exposures. Nonetheless, the hazard is used for commercial purposes to suggest misleadingly that ambient environmental light can cause acute retinal phototoxicity and increase the risk of AMD. Very large epidemiological studies show that blue-blocking IOLs do not reduce the risk or progression of AMD. Additionally, blue-filtering IOLs or spectacles cannot decrease glare disability, because they decrease image and glare illuminance in the same proportion. Blue light is essential for older adults' scotopic photoreception needed to reduce the risk of nighttime falling and related injuries. It is also critical for circadian photoreception that is essential for good health, sleep and cognitive performance. Unfortunately, age-related pupillary miosis, retinal rod and ganglion cell photoreceptor degeneration and decreased outdoor activity all reduce the amount of healthful blue light available to older adults. Blue-restricting IOLs further reduce the available blue light at a time when older adults need it most. Patients and ophthalmologists are exposed to hypothesis-based advertisements for blue-filtering optical devices that suppress short wavelength light critical for vision in dim lighting and for good physical and mental health. Spectacle and intraocular lens selections should be based on scientific fact, not conjecture. Ideal IOLs should improve photoreception rather than limit it permanently. Practice efficiency, surgical convenience and physician-manufacturer relationships may eliminate a patient's opportunity to choose between colorless blue-transmitting IOLs and yellow-tinted, blue-restricting IOLs. Cataract surgeons ultimately determine whether their patients have the opportunity to make an informed choice about their future photoreception.

[Light sources usable by the plastic surgeon in the absence of photographic studio]

Medical photography is an important part of the medical file and is widely used in medical communication, especially in our discipline. His practice has to be the most standardized and reproducible as possible, which distinguishes it from artistic photography. Photography fix the light reflecting from a subject, so surgeon have to control of the light source in any environment. In the absence of dedicated studio, using external cobra or ring flashes with special diffusers allow the surgeon to have light sources adapted to the different conditions encountered in daily practice.

Safety and efficacy of a growth factor and cytokine-containing topical product in wound healing and incision scar management after upper eyelid blepharoplasty: a prospective split-face study

Purpose

To evaluate the efficacy and safety of a topical product containing a mixture of growth factors and cytokines on the incision scar following upper eyelid blepharoplasty.

Methods

This is a prospective, single-blinded, and split-face study on patients who underwent bilateral upper eyelid blepharoplasty. Two weeks after surgery, one eye of each subject was randomized to receive Lumière Bio-Restorative Eye Cream on one eyelid incision for 12 weeks and no treatment on the other eyelid. Subjects returned at the postoperative weeks 6, 10, and 14. At each visit, patients and the investigator (who was blinded to the treated eyelid) evaluated the scar through specified questionnaires.

Results

A total of 20 subjects with a mean age of 66.3±9.2 years completed the study. Minor side effects were noted in three subjects. At all-time points, all subjects thought eyelids treated with Lumière had a better scar and overall appearance than fellow eyelids (P<0.5); and 60% of patients strongly encouraged others to use the product. The investigator assessment of erythema and pigmentation revealed less erythema and pigmentation in treated eyes at the weeks 6 and 10, although the difference was statistically insignificant. Investigator assessment also revealed a better scar appearance at week 10 in treated eyes (P=0.04). All evaluation parameters were similar in both eyes at the last visit.

Conclusion

Lumière eye cream shows an excellent safety profile and minimal effects on features of the incision scar following upper lid blepharoplasty. It may hasten the wound healing process considering the higher outcomes at the first weeks of application.

[Stimuli-sensitive polymer systems]

The polymers can be found in different forms in solution (particles, capsules, pseudo-micelles, hydrogels…) or on surface with important prospects in many field applications. These polymer systems are particularly very good candidates to entrap, transport and deliver an active substance in biomedical applications however with many limitations on control of release of a given target. The stimuli-sensitive polymers, also called smart or environmentally sensitive polymers, present physical or chemical changes under the action of small variations of an external stimulus. This signal acts as a stimulus which causes the change of conformation and/or solvation of the macromolecular chains by modifying their various interactions. The stimuli are classified into two broad categories: physical or external stimuli: temperature, mechanical stress, light, magnetic and electric fields; chemical and biochemical or internal stimuli: pH, ionic strength, chemical molecule (glucose, redox) or biochemical (enzymes, antigens…). The use of stimuli-sensitive pathway is widely used in the literature to enhance or trigger the release of an active compound. In this paper, we present the different stimuli addressing the theoretical aspects, polymers corresponding to these stimuli. Some examples illustrate these systems for the controlled release of active compounds.