Study Documents ​​Structural Optic Nerve Head Alterations Due to Axial Elongation

Implementation of myopia management has gained steam in recent years as more clinicians recognize the value of offering such interventions in their practices. The seminal ATOM1 and ATOM2 trials were conducted over a decade ago, so the earliest treated children are now becoming adults. Researchers interested in potential longer-term effects of myopia on the eye published a new paper in Ophthalmology Science that analyzed data from 148 ATOM2 participants. All included were treated with daily instillation of atropine in concentrations of 0.01%, 0.1% or 0.5%. At the 15-year recall, OCT was performed, focused on the optic disc. The study findings suggest the effects of axial elongation specifically in shaping optic nerve morphology and risk factors associated with myopia. These images from the study show examples of two different study participants at the three timepoints analyzed. Photo: Eppenberger LS, et al.Ophthalmol Sci. September 4, 2025. Click image to enlarge. The investigators found that, across atropine groups, comparisons showed similar optic nerve head (ONH) characteristics. Myopic refractive error got worse with time, with a baseline average of -4.54D, increasing to -6.35D at five years and -6.88D at 15 years. Axial length also increased on average from 25.1mm to 26.3mm. One significant change in ONH parameters after 15 years fell under the category of parapapillary atrophy (PPA), with the beta zone to maximal disc diameter ratio increasing from 0.19 to 0.31. The position of the central retinal vascular trunk ratio also increased from 1.62 to 2.23.Upon multivariable analysis, a confirmed association was seen with age, axial length and spherical equivalent with optic disc changes. Axial length, spherical equivalent and PPA were also associated with alterations to Bruch’s membrane opening (BMO) area or the gamma zone. Another association existed between age, PPA ratio and disc-fovea distance ratio with a myopic progression of more than -2.00D during the 15-year observation.The authors of the study elaborated that the increase seen in beta zone ratio occurred parallel to the axial length increase, with more rapid increase in the first five years, when kids were ages nine to 14, the continued to augment but with a flatter slope. The central retinal vascular trunk ratio exit displayed a small nasal shift, which was more pronounced in the second half of the observation window, when participants would be 14 to 24 years old.One hypothesis offered by the researchers to account for these observed changes may be “that axial elongation is associated with a shift of BMO usually towards the macular direction, explaining the overhanging of Bruch’s membrane into the intrapapillary region (i.e., temporal gamma zone), and the ovalization of the optic disc shape due to the shortening of the horizontal optic disc diameter.”They further suggest that “it may be clinically relevant to monitor the ONH into young adulthood, especially to better understand the factors that may cause further complications. Also, the presence of beta zone and gamma zone PPA, if observed early on, may be indicative of future progression and the need for a prompt clinical intervention to slow down ocular growth.”Click here for the journal source. Eppenberger LS, Cheong EZK, Chung J, et al. Optic nerve head changes over 15 years – from the Atropine Treatment Long-Term Assessment Study. Ophthalmol Sci. September 4, 2025. [Epub ahead of print].  This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.