An eye is considered lazy when vision is mildly to severely reduced. This can be due to a variety of reasons but the most common causes are high prescriptions and crossed eyes. Interestingly it is not the eye that is “lazy”, rather the brain’s vision center. In my practice I do not use the term lazy eye. Instead I use the more appropriate medical term “amblyopia” to describe the eye condition that is prevalent in 2% of the population.
Amblyopia begins early in childhood during critical developmental years. Neuron pathways are forming during this time and what our eyes see (or do not see) affects how good our vision develops. In fact the amazing thing about human neurological development is the ability of our brain to adapt and change according to environmental stimuli. Early in our lives our brain uses input from the environment to form patterns that allow it to be more efficient. Eventually, it loses plasticity and the ability to adjust to new patterns decreases significantly. In the case of amblyopia, the brain learns to shut out input from an eye with an uncorrected prescription or crossed eye. Traditionally doctors have considered this to be a permanent reduction in vision when not corrected by age 8.
A new solution?
Researchers Kevin Duffy and Donald Mitchell of Dalhousie University recently conducted a study to return the brain back to its early development stages in an attempt to increase its flexibility. They believe this can serve to reset the brain. The study was conducted on kittens with induced amblyopia who were immersed in a pitch black room for ten days. After the ten days vision significantly improved in all subjects! The positive results of the experiments led researchers to believe the treatment may work on children and young adults with amblyopia. However, in order for this treatment to be effective subjects must be completely isolated from light for long periods of time.
The practicality of this treatment is questionable and I am not yet recommending patients to stay in a pitch dark room for an extended period of time. I am optimistic about the possibility of a brain “reset” and look forward to further developments. I will still maintain that the key to an amblyopia treatment program is to start at an early age while the brain has great plasticity.
Written with Ian Gao, Optometry Intern, College of Optometry ,Western University of Health Sciences