Friday, July 8, 2011

Prozac & Vision Problems in DS

DS symptoms include a myriad of vision issues: strabismus, nygastimus, esotropia, refraction errors. Jett had nystagmus (really bad ocular flutter--like that guy in the movie The Crying Game). He was cured through TCM: accupressure, herbal teas etc. Western medicine says it's incurable.
On Prozac, I didn't see a sudden difference in Jett except that his crossing eyes had slowly cleared up, which I did attribute to Prozac, but had forgotten just how bad his eyes were. I had taken it for granted. But, once I took Jett off Prozac for 2 weeks, I saw just how much Prozac was helping him.
Off Prozac his eyes were crossing so much that he had to turn his head all over the place to try to see better. At times, his eyes were as bad as a googly-eyed doll! His left eye went inward a lot and the right eye... I'm not quite sure.
Perhaps because of the vision issues, I couldn't leave him to play independently anymore because he would find a sock or some string to wave in front of his face and go, "Eeeeeeeeeeeeee," until I redirected him. This may be because he was trying to self stimulate his vision in order to try to correct. (See post Some TV is Good for Our Kids!) This stimming behavior would happen within five minutes of setting him on the floor to play.
His vision is much too important for me to mess with.... Back on Prozac for only 3 days, he can play independently again because the stimming is gone and his eyes are much better--not completely gone, but hopefully will clear up again sooner than later.

These eye issues can lead to amblyopia. Amblyopia is where the brain turns off the vision to one eye and depth perception is lost.
Many individuals with DS have to do the "Step-step" on stairs rather than alternating feet on the steps. You need depth perception. Jett's been crawling on the stairs great since his eyes were fixed--we just took down his stairs to have our sofa back for company (his stairs were made out of sofa cushions), but I can't imagine him trying to walk them with poor vision!

It is hard to learn, have coordination, alternate you feet on the steps, if you can not see.

Can you imagine trying to read with the vision issues our kids have?
The following study abstract detail the severity of the vision problems.
GOAL: Improved vision to improve learning.
Wikipedia: Amblyopia is a developmental problem in the brain, not an organic problem in the eye (although organic problems can give rise to amblyopia which continue to exist after the organic problem has resolved).[4] The part of the brain receiving images from the affected eye is not stimulated properly and develops abnormally

Amblyopia and visual acuity in children with Down's syndrome.

Department of Ophthalmology, Rhode Island Hospital/Brown University School of Medicine, Providence, RI 02903, USA.Abstract

BACKGROUND/AIMS: Amblyopia in people with Down's syndrome has not been well investigated. This study was designed to determine the prevalence and associated conditions of amblyopia in a group of home reared children with Down's syndrome.

METHODS: All children in the study group underwent an evaluation of visual acuity. In addition, previous ophthalmological records were reviewed, and a subgroup of children was examined. For the purposes of this study, amblyopia was defined quantitatively as a difference of two Snellen acuity lines between eyes or if unilateral central steady maintained (CSM) vision and a clear fixation preference was observed. A high refractive error was defined as a spherical equivalent more than 3 dioptres and astigmatism more than 1.75 dioptres. Anisometropia was defined as a difference of at least 1.5 dioptres of sphere and/or 1.0 dioptre of cylinder between eyes. 68 children with Down's syndrome between the ages of 5 and 19 years were enrolled in the final study group.

RESULTS: Amblyopia was observed in 15 (22%) of 68 patients. An additional 16 (24%) patients had bilateral vision less than 20/50. Strabismus, high refractive errors, and anisometropia were the conditions most commonly associated with decreased vision and amblyopia

CONCLUSION: This study suggests that the prevalence of amblyopia is higher than previously reported. Fully 46% of these children with Down's syndrome had evidence of substantial visual deficits. These patients may be at higher risk for visual impairment and should be carefully examined for ophthalmological problems.

Visual acuity and accommodation in infants and young children with Down's syndrome.

by J M Woodhouse, V H Pakeman, K J Saunders, M Parker, W I Fraser, S Lobo, P Sastry
Accommodation and visual acuity were measured in 53 children with Down's syndrome aged between 12 weeks and 57 months. Results were compared with data for 136 control (typically developing) children aged between 4 weeks and 48 months. Whereas the control children accommodated accurately on near targets, accommodation was defective in 92% of the children with Down's syndrome, and there was no change in accommodative ability with age. On the other hand, visual acuity lay within normal limits for the younger children. Children over the age of 2 years showed a below-normal visual acuity, which is not explained either by refractive error or by the effect of poor accommodation. The data suggest a sudden change in the rate of development of visual acuity which may be associated with physiological changes in the visual cortex. Previously reported defects of accommodation and visual acuity in older children and adults with Down's syndrome are confirmed by our findings in infants and young children.

Visual acuity in infants and children with Down syndrome.

by M L Courage, R J Adams, S Reyno, P G Kwa
The authors used the Teller acuity cards to assess the visual acuity of 51 infants and children with Down syndrome aged between two months and 18 years. The success rate and test times were comparable to those reported for normally developing children. Even those DS subjects in the study who were free of ocular disorders and/or who were wearing optical correction during testing showed significantly poorer visual acuity than individuals without Down syndrome. The development of visual acuity in infants and children with Down syndrome lags behind that of age-matched peers without Down syndrome, especially after the age of six months. These findings are discussed in terms of the neurological and optical factors that might account for the deficits in visual acuity that were observed
Is the selective serotonin reuptake inhibitor fluoxetine (Prozac) a fountain of youth?
Elizabeth M Quinlan​‌
Evaluation of: Maya Vetencourt JF, Sale A, Viegi A et al.: The antidepressant fluoxetine restores plasticity in the adult visual cortex. Science 320, 385–288 (2008). The potential for synaptic strength to be regulated by experience is high early in postnatal life, and declines thereafter. The constraint of synaptic plasticity in the adult visual system is thought to underlie the resistance to therapy for the treatment of amblyopia. However, a recent report by Maya Vetencourt et al. demonstrates that systemic administration of the popular antidepressant fluoxetine reactivates synaptic plasticity in the visual system of adult rats, and enables the recovery of function in an eye chronically deprived of vision. Fluoxetine administration stimulated a decrease in basal levels of extracellular GABA, an increase in the level of BDNF and the return of long-term potentiation in slices of visual cortex. The ability to reactivate robust synaptic plasticity in the adult mammalian visual system has clear therapeutic potential for the treatment of amblyopia in adults.

The Antidepressant Fluoxetine Restores Plasticity in the Adult Visual Cortex

  1. José Fernando Maya Vetencourt1,*, Alessandro Sale1,Alessandro Viegi1,
  2. Laura Baroncelli1, Roberto De Pasquale1, Olivia F. O'Leary3, Eero Castrén3 and Lamberto Maffei1,22 Institute of Neuroscience, Consiglio Nazionale delle Recerche, Via Moruzzi 1, I-56100 Pisa, Italy.
  3. 3 Neuroscience Centre, University of Helsinki, 00014 Helsinki, Finland.
  4. * To whom correspondence should be addressed. E-mail: jf.maya@in.cnr.it

Abstract

We investigated whether fluoxetine, a widely prescribed medication for treatment of depression, restores neuronal plasticity in the adult visual system of the rat. We found that chronic administration of fluoxetine reinstates ocular dominance plasticity in adulthood and promotes the recovery of visual functions in adult amblyopic animals, as tested electrophysiologically and behaviorally. These effects were accompanied by reduced intracortical inhibition and increased expression of brain-derived neurotrophic factor in the visual cortex. Cortical administration of diazepam prevented the effects induced by fluoxetine, indicating that the reduction of intracortical inhibition promotes visual cortical plasticity in the adult. Our results suggest a potential clinical application for fluoxetine in amblyopia as well as new mechanisms for the therapeutic effects of antidepressants and for the pathophysiology of mood disorders.

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