Myopia has emerged as a major health issue in east Asia, especially the sight-threatening complications associated with high myopia (HM). Complication of HM can be associated with significant ocular morbidities including maculopathy, retinal detachment, and glaucoma.~Previous studies have shown that adult patients with HM have sustained growth of the axial length (AL), which is a risk factor for the progression of pathological myopia and thus may further affect the visual function , so how to slow down the sustained growth of the AL in adult patients with HM has become an urgent clinical problem. Previous studies have shown that IOP-lowering treatment is a protective factor for the growth of the AL in HM , and the results of animal experiments have further shown that medically IOP-lowering treatment can significantly slow down the AL lengthening and refractive changes in the guinea pig model of myopia. On this basis, the investigators proposed in a previous article that medically IOP-lowering treatment may slow down the growth of AL by three pathways related to the sclera and choroid: for the sclera, IOP-lowering treatment may reduce the scleral distending force, slow down the rate of scleral distension, and inhibit the activation of scleral fibroblasts to reduce scleral remodeling; for the choroid, IOP-lowering treatment may increase choroidal blood perfusion and for the choroid, hypotensive treatment can increase choroidal perfusion and thus reduce scleral remodeling due to scleral hypoxia. A previous retrospective study conducted by the investigators also shows that medically IOP-lowering treatment could control the progression of AL in HM, but there is still a lack of evidence from relevant robust randomized controlled clinical trials (RCT).~The investigators propose to conduct a RCT to evaluate whether medically IOP-lowering therapy is effective in controlling the progression of AL in HM. Secondly, this study also aims to provide data to evaluate IOP-lowering treatment effects on the incidence of changes in the visual field (VF), optic nerve head morphology including the retinal nerve fiber layer (RNFL), and retinal ganglion cell-inner plexiform layer (GC-IPL) loss, progression of myopic maculopathy, loss in visual function and change in quality of life. The outcomes of this study may provide a strong basis for treatment recommendations to control the progression of high myopic eyes, and to provide high-quality clinical research evidence for international clinical guidelines on myopia.
Currently, whether and when intraocular pressure (IOP) lowering medication should be used in progressive high myopia (HM) to control axial elongation is still a dilemma. Randomized trials are required to evaluate whether IOP lowering influences the growth of axial length in progressive HM eyes.