Systemic 7-methylxanthine in retarding axial eye growth and myopia progression: a 36-month pilot study

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Abstract

The adenosine antagonist 7-methylxanthine (7-mx) works against myopia in animal models. In a clinical trial, 68 myopic children (mean age 11.3 years) received either placebo or 7-mx tablets for 12 months. All participants subsequently received 7-mx for another 12 months, after which treatment was stopped. Axial length was measured with Zeiss IOL-Master and cycloplegic refraction with Nikon Retinomax at −6, 0, 12, 24, and 36 months. Axial growth was reduced among children treated with 7-mx for 24 months compared with those only treated for the last 12 months. Myopia progression and axial eye growth slowed down in periods with 7-mx treatment, but when the treatment was stopped, both myopia progression and axial eye growth continued with invariable speed. The results indicate that 7-mx reduces eye elongation and myopia progression in childhood myopia. The treatment is safe and without side effects and may be continued until 18–20 years of age when myopia progression normally stops.

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Most cited references 45

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Mechanisms of maturation and ageing of collagen.

Allen J Bailey, Robert Gordon Paul, Lynda Knott (1998)

The deleterious age-related changes in collagen that manifest in the stiffening of the joints, the vascular system and the renal and retinal capillaries are primarily due to the intermolecular cross-linking of the collagen molecules within the tissues. The formation of cross-links was elegantly demonstrated by Verzar over 40 years ago but the nature and mechanisms are only now being unravelled. Cross-linking involves two different mechanisms, one a precise enzymically controlled cross-linking during development and maturation and the other an adventitious non-enzymic mechanism following maturation of the tissue. It is this additional non-enzymic cross-linking, known as glycation, involving reaction with glucose and subsequent oxidation products of the complex, that is the major cause of dysfunction of collagenous tissues in old age. The process is accelerated in diabetic subjects due to the higher levels of glucose. The effect of glycation on cell-matrix interactions is now being studied and may be shown to be an equally important aspect of ageing of collagen. An understanding of these mechanisms is now leading to the development of inhibitors of glycation and compounds capable of cleaving the cross-links, thus alleviating the devastating effects of ageing.

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Adenosine as a neuromodulator and as a homeostatic regulator in the nervous system: different roles, different sources and different receptors.

R.A. Cunha (2001)

Adenosine exerts two parallel modulatory roles in the CNS, acting as a homeostatic modulator and also as a neuromodulator at the synaptic level. We will present evidence to suggest that these two different modulatory roles are fulfilled by extracellular adenosine originated from different metabolic sources, and involve receptors with different sub-cellular localisation. It is widely accepted that adenosine is an inhibitory modulator in the CNS, a notion that stems from the preponderant role of inhibitory adenosine A(1) receptors in defining the homeostatic modulatory role of adenosine. However, we will review recent data that suggests that the synaptically localised neuromodulatory role of adenosine depend on a balanced activation of inhibitory A(1) receptors and mostly facilitatory A(2A) receptors. This balanced activation of A(1) and A(2A) adenosine receptors depends not only on the transient levels of extracellular adenosine, but also on the direct interaction between A(1) and A(2A) receptors, which control each other's action.

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Eye shape in emmetropia and myopia.

N Pritchard, M Pope, David Atchison … (2004)

To determine axial, vertical, and horizontal eye dimensions in myopic and emmetropic eyes by using magnetic resonance imaging (MRI) and to relate these to different ocular expansion models of myopia development. The internal length (cornea to retina), height and width (both retina to retina) were measured in emmetropic and myopic eyes (up to -12 D) of 88 participants aged 18 to 36 years. Participants were positioned supine in a clinical MRI scanner. The fixation target was imaged straight ahead of the subject by an overhead 45 degrees inclined mirror. Eye images were acquired with a 7.5-cm receive-only radio frequency surface coil. Axial (horizontal through middle of eye) and sagittal (vertical through visual axis) sections were taken with a T(1)-weighted fast spin-echo sequence. With an increase in myopic refractive correction, myopic eyes became much larger in all three dimensions, but more so in length (0.35 mm/D, 95% confidence interval [CI] 0.28-0.40) than in height (0.19 mm/D, 95% CI 0.09-0.29) and more so in height than in width (0.10 mm/D, 95% CI 0.01-0.20). Based on height and length dimensions, 25% and 29% of myopic eyes exclusively fitted global expansion and axial elongation models, respectively. Based on width and length dimensions, 17% and 39% of myopic eyes exclusively fitted the global expansion and axial elongation models, respectively. Although there are considerable individual variations, in general myopic eyes are elongated relative to emmetropic eyes, more in length than in height and even less in width. Approximately a quarter of the myopic participants fitted each of the global expansion or axial elongation model exclusively. The small proportions are due primarily to the large variability in the dimensions of emmetropic eyes.

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Author and article information

Contributors

: +45-39625663 , +45-39625642 , ktrier@dadlnet.dk

Journal

Journal ID (nlm-ta): J Ocul Biol Dis Infor

Title: Journal of Ocular Biology, Diseases, and Informatics

Publisher: Humana Press Inc (New York )

ISSN (Print): 1936-8437

ISSN (Electronic): 1936-8445

Publication date (Electronic): 4 November 2008

Publication date PMC-release: 4 November 2008

Publication date (Print): December 2008

Volume: 1

Issue: 2-4

Pages: 85-93

Affiliations

[1 ]Trier Research Laboratories, Tingskiftevej 6, 2900 Hellerup, Denmark

[2 ]State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China

[3 ]Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Copenhagen, Denmark

Article

Publisher ID: 9013

DOI: 10.1007/s12177-008-9013-3

PMC ID: 2802512

PubMed ID: 20072638

SO-VID: 4c520d56-af56-4b21-a3e6-4f5a37d54b2c

History

Date received : 19 June 2008

Date accepted : 22 September 2008

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ScienceOpen disciplines: Vision sciences

Keywords: adenosine receptor antagonist,myopia,7-methylxanthine,clinical trial

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ScienceOpen disciplines: Vision sciences

Keywords: adenosine receptor antagonist, myopia, 7-methylxanthine, clinical trial

Systemic 7-methylxanthine in retarding axial eye growth and myopia progression: a 36-month pilot study

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Abstract

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Karger: Ophthalmology

Most cited references 45

Mechanisms of maturation and ageing of collagen.

Adenosine as a neuromodulator and as a homeostatic regulator in the nervous system: different roles, different sources and different receptors.

Eye shape in emmetropia and myopia.

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