Can human amblyopia be treated in adulthood?

Amblyopia is a common visual disorder that results in a spatial acuity deficit in the affected eye. Orthodox treatment is to occlude the unaffected eye for lengthy periods, largely determined by the severity of the visual deficit at diagnosis. Although this treatment is not without its problems (poor compliance, potential to reduce binocular function, etc) it is effective in many children with moderate to severe amblyopia. Diagnosis and initiation of treatment early in life are thought to be critical to the success of this form of therapy. Occlusion is rarely undertaken in older children (more than 10 years old) as the visual benefits are considered to be marginal. Therefore, in subjects where occlusion is not effective or those missed by mass screening programs, there is no alternative therapy available later in life. More recently, burgeoning evidence has begun to reveal previously unrecognized levels of residual neural plasticity in the adult brain and scientists have developed new genetic, pharmacological, and behavioral interventions to activate these latent mechanisms in order to harness their potential for visual recovery. Prominent amongst these is the concept of perceptual learning—the fact that repeatedly practicing a challenging visual task leads to substantial and enduring improvements in visual performance over time. In the normal visual system the improvements are highly specific to the attributes of the trained stimulus. However, in the amblyopic visual system, learned improvements have been shown to generalize to novel tasks. In this paper we ask whether amblyopic deficits can be reduced in adulthood and explore the pattern of transfer of learned improvements. We also show that developing training protocols that target the deficit in stereo acuity allows the recovery of normal stereo function even in adulthood. This information will help guide further development of learning-based interventions in this clinical group

Interactive binocular treatment (I-BiT) for amblyopia: results of a pilot study of 3D shutter glasses system

NoPURPOSE: A computer-based interactive binocular treatment system (I-BiT) for amblyopia has been developed, which utilises commercially available 3D 'shutter glasses'. The purpose of this pilot study was to report the effect of treatment on visual acuity (VA) in children with amblyopia. METHODS: Thirty minutes of I-BiT treatment was given once weekly for 6 weeks. Treatment sessions consisted of playing a computer game and watching a DVD through the I-BiT system. VA was assessed at baseline, mid-treatment, at the end of treatment, and at 4 weeks post treatment. Standard summary statistics and an exploratory one-way analysis of variance (ANOVA) were performed. RESULTS: Ten patients were enrolled with strabismic, anisometropic, or mixed amblyopia. The mean age was 5.4 years. Nine patients (90%) completed the full course of I-BiT treatment with a mean improvement of 0.18 (SD=0.143). Six out of nine patients (67%) who completed the treatment showed a clinically significant improvement of 0.125 LogMAR units or more at follow-up. The exploratory one-way ANOVA showed an overall effect over time (F=7.95, P=0.01). No adverse effects were reported. CONCLUSION: This small, uncontrolled study has shown VA gains with 3 hours of I-BiT treatment. Although it is recognised that this pilot study had significant limitations-it was unblinded, uncontrolled, and too small to permit formal statistical analysis-these results suggest that further investigation of I-BiT treatment is worthwhile

Antihypertensive drugs and vascular health

Hypertension is a growing health burden and contributes to serious cardiovascular complications from target organ damage. The vascular system is particularly important in patients with elevated blood pressure, because vascular dysfunction is both a cause and consequence of hypertension. Hypertension is characterised by a vascular phenotype of endothelial dysfunction, vascular inflammation, arterial remodelling and increased stiffness. Of the many classes of antihypertensive drugs, those that influence vascular health have the greatest efficacy for reducing cardiovascular risk. Angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers and calcium channel blockers ameliorate vascular remodelling and improve endothelial function. Mineralocorticoid receptor antagonists reduce arterial stiffness, improve endothelial function and are established antihypertensive drugs, particularly in patients with resistant hypertension. Patients prone to salt-sensitivity benefit from diuretics, which influence salt physiology and balance and reduce arterial stiffness. Not all antihypertensive drugs are vasoprotective. Beta blockers, like atenolol, reduce blood pressure, but do not regress remodelling and fail to improve endothelial function. Selecting and refining the optimum drug therapy for the treatment of hypertension remains the key challenge and should prompt thought about the diverse pathophysiological mechanisms involved. This should always be in association with lifestyle modifications, which remains a cornerstone in preventing and improving vascular changes associated with high blood pressure