Form deprivation and lens-induced myopia: are they different?

Abstract

In the following point-counterpoint article, internationally-acclaimed myopia researchers were challenged to defend the two opposing sides of the topic defined by the title; their contributions, which appear in the order Point followed by Counterpoint, were peer-reviewed by both the editorial team and an external reviewer. Independently of the invited authors, the named member of the editorial team provided an Introduction and Summary, both of which were reviewed by the other members of the editorial team. By their nature, views expressed in each section of the Point-Counterpoint article are those of the author concerned and may not reflect the views of all of the authors.

Figure 1

ADTN suppresses reduced Egr-1 expression in both FDM and LIM. Chickens were injected intravitreally with the non-specific dopamine agonist ADTN (6,7-amino-5,6,7,8-tetrahydronaphthalene-2,3-diol hydrobromide) just prior to the fitting of diffusers to induce form-deprivation myopia or negative lenses to induce lens-induced myopia. Fitting of diffusers and negative lenses both reduced Egr-1 mRNA expression after 1 h. This down-regulation was reversed in both cases by prior injection of ADTN.

Figure 2

Effects of parasympathectomy (PPG/CGX) on refractive error and axial elongation in form deprived and negative lens-wearing eyes. (a) Effects of 5 days of form deprivation. Top: Effects on refractive error in lesioned eyes (PPG/CGX) vs intact (non-lesioned) control eyes; ‘fellow’ are the combined contralateral controls in all graphs. Bottom: Effects on axial elongation; blue bars: form deprived eyes; white bars: fellow control eyes. (b) Effects of 5 days of negative lens-wear. Top: Effects on refractive error in lesioned eyes (PPG/CGX) vs intact (non-lesioned) control eyes. Bottom: Effects on axial elongation; green bars: lens-wearing eyes; white bars: fellow control eyes. Note that lesioned form deprived eyes grow slower than normal (fellow), and do not become myopic, while lesioned eyes wearing negative lenses grow faster than normal (fellow) and become as myopic as intact controls. * p < 0.05; **p < 0.005.