Final Activity Report Summary - MY EUROPIA (European Training in Myopia Research)
MYEUROPIA, a European network of expertise in research on myopia, provided an excellent platform for the training of ambitious young researchers and addressed urgent challenges in myopia research, pursuing three different approaches.
1. Visual determinants of myopia Peripheral image quality is suggested as a possible cue that drives an eye to grow myopic. Therefore new radial refractive gradient lenses (RRG lenses) were designed and developed (by the industrial partner of MYEUROPIA, the company Rodenstock), and were tested in humans and in chickens regarding their optical effects in the eye. Furthermore, wearing comfort in humans was quantified. Moreover, optical instruments;
(i) to scan peripheral refraction in humans fast and with high angular resolution and,
(ii) to measure off-axis the image quality in a large population were developed.
It was shown;
(i) that eyes even in low myopic people are more "bumpy" in shape than in emmetropes,
(ii) that the RRG lenses produced the desired peripheral myopia,
(iii) that the variability of peripheral refractions in humans is very high and does not change with accommodation, and that the peripheral refraction profiles can be clustered into 4 groups.
The new scanning infrared photorefractor compared well with the new scanning Hartman-Shack sensor that was also implemented in the course of MYEUROPIA. Furthermore it was found that in chickens the setpoint of emmetropiSation appears to be inherited whereas the "gain" of emmetropiSation showed only low endogenous control. In different studies, it was found that high light levels are protective against excessive eye growth in chicks, suggesting that school children should spend more time outdoors. The achieved findings contributed significantly to the knowledge on the influence of peripheral image quality on myopia development and will continue to be valuable in solving the riddle and probably contribute to the design of optical correction measures to reduce the progression of myopia.
2. Genetic determinants of myopia. Both family history and visual activity are implicated in causing myopia, but studies in children have explained less than 15% of the risk. It was shown that interactions between genes and visual cues explain more than 50% of the risk, suggesting a new avenue for myopia research. Also in the largest twin study to date, the importance of genetic factors in myopia was demonstrated, explaining almost 80% of variation. The effort of a large international consortium was led that allowed to identify a genetic variant (in the gene RASGRF1) that strongly predisposes to myopia in the general population; work with other international teams resulted in the discovery of further genetic variants on chromosome 15.
Findings related to work on the genetics of astigmatism has recently received much attention by both the scientific community but also by the general public and press. Moreover, a genome-wide association study with the goal of mapping new loci on the genome carrying genes linked to myopia development was initiated.
3. Signalling cascade and pharmacological intervention of myopia Gene expression analyses revealed that different retinal pathways are involved in development of hyperopia and myopia. Insulin and/or IGF-1 may play a role during eye growth regulation, since the mRNA level of their receptors are influenced by defocus in chickens. Insulin injections lead to myopia, even in eyes treated with plus lenses, which normally induce hyperopia. It also was found that glial cells of the retina are mechanoresponsive; stretching the retina triggers an intracellular signalling chain including Ca2+ rises and expression of bFGF which might be involved in the control of eye growth. Moreover, experimental collagen crosslinking was shown to increase the stiffness of the sclera and to decelerate eye growth in postnatal rabbits, without any obvious damage to the retina. This treatment may in future be applied to human patients with malign myopia.
1. Visual determinants of myopia Peripheral image quality is suggested as a possible cue that drives an eye to grow myopic. Therefore new radial refractive gradient lenses (RRG lenses) were designed and developed (by the industrial partner of MYEUROPIA, the company Rodenstock), and were tested in humans and in chickens regarding their optical effects in the eye. Furthermore, wearing comfort in humans was quantified. Moreover, optical instruments;
(i) to scan peripheral refraction in humans fast and with high angular resolution and,
(ii) to measure off-axis the image quality in a large population were developed.
It was shown;
(i) that eyes even in low myopic people are more "bumpy" in shape than in emmetropes,
(ii) that the RRG lenses produced the desired peripheral myopia,
(iii) that the variability of peripheral refractions in humans is very high and does not change with accommodation, and that the peripheral refraction profiles can be clustered into 4 groups.
The new scanning infrared photorefractor compared well with the new scanning Hartman-Shack sensor that was also implemented in the course of MYEUROPIA. Furthermore it was found that in chickens the setpoint of emmetropiSation appears to be inherited whereas the "gain" of emmetropiSation showed only low endogenous control. In different studies, it was found that high light levels are protective against excessive eye growth in chicks, suggesting that school children should spend more time outdoors. The achieved findings contributed significantly to the knowledge on the influence of peripheral image quality on myopia development and will continue to be valuable in solving the riddle and probably contribute to the design of optical correction measures to reduce the progression of myopia.
2. Genetic determinants of myopia. Both family history and visual activity are implicated in causing myopia, but studies in children have explained less than 15% of the risk. It was shown that interactions between genes and visual cues explain more than 50% of the risk, suggesting a new avenue for myopia research. Also in the largest twin study to date, the importance of genetic factors in myopia was demonstrated, explaining almost 80% of variation. The effort of a large international consortium was led that allowed to identify a genetic variant (in the gene RASGRF1) that strongly predisposes to myopia in the general population; work with other international teams resulted in the discovery of further genetic variants on chromosome 15.
Findings related to work on the genetics of astigmatism has recently received much attention by both the scientific community but also by the general public and press. Moreover, a genome-wide association study with the goal of mapping new loci on the genome carrying genes linked to myopia development was initiated.
3. Signalling cascade and pharmacological intervention of myopia Gene expression analyses revealed that different retinal pathways are involved in development of hyperopia and myopia. Insulin and/or IGF-1 may play a role during eye growth regulation, since the mRNA level of their receptors are influenced by defocus in chickens. Insulin injections lead to myopia, even in eyes treated with plus lenses, which normally induce hyperopia. It also was found that glial cells of the retina are mechanoresponsive; stretching the retina triggers an intracellular signalling chain including Ca2+ rises and expression of bFGF which might be involved in the control of eye growth. Moreover, experimental collagen crosslinking was shown to increase the stiffness of the sclera and to decelerate eye growth in postnatal rabbits, without any obvious damage to the retina. This treatment may in future be applied to human patients with malign myopia.