Fluoxetine does not enhance the effect of perceptual learning on visual function in adults with amblyopia

Henri J Huttunen,Elina Karvonen,J Matias Palva,Laura Lindberg,Hannu Uusitalo,Satu Palva,Eero Castrén,Ville Saarela,Marja-Leena Latvala,Johanna Liinamaa,Sigrid Booms

doi:10.1038/s41598-018-31169-z

Henri J Huttunen, Elina Karvonen + Show 9 more

Open Access

https://doi.org/10.1038/s41598-018-31169-z

Copy DOI

Abstract

Amblyopia is a common visual disorder that is treatable in childhood. However, therapies have limited efficacy in adult patients with amblyopia. Fluoxetine can reinstate early-life critical period-like neuronal plasticity and has been used to recover functional vision in adult rats with amblyopia. We conducted a Phase 2, randomized (fluoxetine vs. placebo), double-blind, multicenter clinical trial examined whether or not fluoxetine can improve visual acuity in amblyopic adults. This interventional trial included 42 participants diagnosed with moderate to severe amblyopia. Subjects were randomized to receive either 20 mg fluoxetine (n = 22) or placebo (n = 20). During the 10-week treatment period, all subjects performed daily computerized perceptual training and eye patching. At the primary endpoint, the mean treatment group difference in visual acuity improvement was only 0.027 logMAR units (95% CI: −0.057 to 0.110; p = 0.524). However, visual acuity had significantly improved from baseline to 10 weeks in both fluoxetine (−0.167 logMAR; 95% CI: −0.226 to −0.108; p < 0.001) and placebo (−0.194 logMAR; 95% CI: −0.254 to −0.133; p < 0.001) groups. While this study failed to provide evidence that fluoxetine enhances neuroplasticity, our data support other recent clinical studies suggesting that improvement of vision can be accomplished in adults with amblyopia.

Highlights

Amblyopia is a condition in which the best-corrected visual acuity (BCVA) is impaired in one eye or, less frequently, both eyes, even though no ocular abnormalities are generally present
Age 18–60 years, male or female Diagnosed with amblyopia due to myopic or hyperopic anisometropia, or, congenital esotropia Visual acuity in the amblyopic eye ≥0.30 and
Despite good screening programs and effective childhood treatments, amblyopia remains a common cause of lifelong visual impairment independent of geographical location or ethnic origin[3,5,6,38]

Summary

Introduction

Amblyopia is a condition in which the best-corrected visual acuity (BCVA) is impaired in one eye or, less frequently, both eyes, even though no ocular abnormalities are generally present. History of any amblyopia therapy in the 2 years before the screening visit Any eye surgery less than 6 months before the screening visit Observed off-fixation by ophthalmological examination (extra-foveal/eccentric fixation) Other ophthalmological pathologies that may affect the patient’s rehabilitation Pregnant, planning to become pregnant during the study, or breast feeding History of depressive illness or treatment with antidepressant medication within 6 months before the screening visit Use of psychiatric medication within 6 months before the screening visit Receipt of an experimental treatment for any disease within 4 weeks before the screening visit History or presence of illicit drug use or alcohol abuse History or presence of any medical or psychiatric condition or disease, or laboratory abnormality that, in the opinion of the Investigator, may place the patient at unacceptable risk or that could prevent the patient from completing the study can be reversed during the critical period in early postnatal development, but not later in life. Fluoxetine, a selective serotonin reuptake inhibitor (SSRI), promotes neuroplasticity and neurogenesis[27] and reactivates critical period-like plasticity in the rat visual cortex[15]

Methods

Results

Conclusion