Light Therapy To Prevent Vision Problems in Preterm Babies

Highlights:

• Light therapy in preterm infants is useful in preventing vision problems by activating a protein called opsin 5 that regulates the development of blood vessels in the eye which is critical for normal vision
• In preterm infants, there is a decreased expression of the opsin 5 protein and normal development of eye blood vessels is therefore affected leading to vision problems
• Eye conditions such as retinopathy of prematurity and severe myopia (near-sightedness) are common in preterm infants

A light-dependent molecular-process has been discovered that controls blood vessel development in the developing eye of babies. This finding may be useful to prevent visual problems in premature infants by using phototherapy, according to scientists at Cincinnati Children's Hospital Medical Center. The findings of the study appear in Nature Cell Biology.

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Role of Opsin 5 & Dopamine in Normal Blood Vessel Development in Eye

• To see what happens when opsin 5 protein is not expressed in the retinal cells (similar to what is seen in preterm infants) the scientists used genetically modified mice to test the response
• They found that loss of opsin 5 led to increased levels of dopamine in the eye.
• The increased dopamine levels caused developing blood vessels to regress rapidly affecting normal visual development

To study the effect of light stimulation on the eye, the team used 380-nanometer violet colored light to activate the opsin 5 protein in the retinal light receptor cells. 

• Activation of opsin 5 protein resulted in reduced dopamine levels in the eye, thus favoring optimal blood vessel development and normal vision

The findings of the study suggest that phototherapy can be used activates opsin 5 protein in preterm infants to promote normal blood vessel development and prevent severe vision problems later.

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What is the Opsin 5-Dopamine Pathway?

• The opsin 5-dopamine pathway is a molecular process occurring in the developing eyes of the baby
• This process depends on specific responses in the retina controlled by opsin 5, a protein that is normally expressed in specialized light receptor cells in the retina
• The opsin 5 protein normally becomes activated by light exposure at the right time to ensure normal vision
• The activated opsin 5 along with the neurotransmitter dopamine (which causes blood vessel loss) work together to ensure optimal and balanced blood vessel development in the eye of the newborn

"Our study indicates opsin 5-dopamine pathway is probably part of a light-dependent disease process for conditions like myopia, which is now a worldwide epidemic," said Richard A. Lang, PhD, director of the Visual Systems Group at Cincinnati Children's and study senior author. "It raises the interesting possibility that we might be able to use light exposure to treat conditions like retinopathy of prematurity after a premature infant is born or in people with myopia."

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Scope of the Study

• In fact, earlier studies have suggested that dopamine together with violet light may be critical to the normal development of the eye
• Although, additional research is needed for the findings to be applied to humans, the current study confirms that opsin 5-dopamine pathway is key for normal vision development in mice and perhaps human babies as well
• According to one of the authors, opsin 5 is protein highly conserved across species during the process of evolution, and increases the likelihood of its presence and importance in humans as well

Summary

The findings of the study show that the opsin 5-dopamine pathway is necessary for balanced blood vessel formation in the newborn and phototherapy may be useful to prevent eye problems in preterm infants.

Reference:

1. An opsin 5–dopamine pathway mediates light-dependent vascular development in the eye - (http://dx.doi.org/10.1038/s41556-019-0301-x)

Source-Medindia