Possible Beneficial Effects Of Combined Fluoxetine And Occlusion Therapy In Improving And Maintaining Vision In Amblyopia Using Optical Coherence Tomography Angiography (OCTA) And Visual Evoked Potential (VEP)

Amblyopia is described as a limitation of the visual function of one or both eyes with no pathological cause, with a prevalence of about 1-5% of the total world population. This disorder is caused by early abnormal visual experience with a functional imbalance between the two eyes owing to anisometropia, strabismus, congenital cataract and ptosis, resulting in a dramatic loss of visual acuity (VA) in an apparently healthy eye.

Clinically, amblyopia can be defined as the presence in one or both eyes of a VA of 6/12 or worse, with one or more lines of difference in VA between eyes in unilateral amblyopia which cannot be improved by refractive correction. This condition is an alteration of the visual cortex function which is due to suppression and deprivation of one eye leading to unilateral visual deterioration.

Optical coherence tomography (OCT) is a noninvasive technique that can reveal morphology of the retinal layers in vivo. OCT determines structural changes in the macula that may be correlated with measures of subjective visual function such as visual acuity and visual field. OCT angiography (OCTA) can provide vascular system visualization of the posterior segment in amblyopic eyes.

Visual evoked potentials (VEPs) are a non-invasive technique routinely used in clinical and preclinical practice. VEPs allow to quantify the functional integrity of the visual system from the retina via the optic nerves, optic tracts, to the thalamus, and form projections to the visual cortices.

In strabismic and anisometropic amblyopia, VEP responses are reduced. VEP may be used as an alternative objective method for diagnosis and monitoring of amblyopia.

Passive treatments such as occlusion, optical and/or pharmacological penalization, and Bangerter foils have been demonstrated to be potentially useful treatments for amblyopia. Researches are being done on new pharmacological options to improve and maintain VA after occlusion treatment in amblyopia.

Adults with amblyopia cannot be treated because their brains do not have enough plasticity. However, results obtained both in clinical trials and in animal models have challenged this traditional view, unmasking a previously unsuspected potential for promoting recovery after the end of the critical period for visual cortex plasticity. These studies point toward the intracortical inhibitory transmission as a crucial brake for therapeutic rehabilitation and recovery from amblyopia in the adult brain.

Selective serotonin reuptake inhibitors (SSRIs) increase serotonin activity in the brain. While they are mostly known for their antidepressant properties, they have been shown to improve visual functions in amblyopia and impact cognitive functions ranging from attention to motivation and sensitivity to reward.