Effectiveness of Digital Defocus Vision Training With Low-Concentration Atropine on the Prevention and Control of Myopia in Children: A Clinical Study

Axial length is defined as the anteroposterior diameter of the eyeball and is a key parameter for assessing ocular refractive status. Generally, each 1-mm increase in axial length corresponds to an approximate increase of 200-300 diopters of myopia. In this trial, axial length measurements were performed by the same experienced examiner, who was masked to treatment allocation, using the same IOLMaster 500 device. Only changes in axial length of the right eye were compared.

Spherical equivalent refraction is defined as the optical lens power required to correct refractive errors (myopia, hyperopia, and astigmatism) for the left and right eyes, as determined by subjective refraction using a phoropter. In this trial, SER measurements were performed by the same experienced examiner, who was masked to treatment allocation, using the same Topcon phoropter under full cycloplegia. Only changes in SER of the right eye were analyzed.

Accommodative facility is an important clinical measure of visual function that assesses the ability to rapidly relax and stimulate accommodation in response to different accommodative demands-i.e., the flexibility and speed of the accommodative response. It is typically measured using a flipper bar (e.g., ±2.00 D lenses). Under full distance correction, the subject views a target while alternately flipping the positive and negative lenses, and the number of successful cycles completed within one minute is recorded. Normal values are ≥8 cycles/min for binocular facility and ≥11 cycles/min for monocular facility. In this trial, accommodative facility measurements were performed by the same experienced examiner, who was masked to treatment allocation, using the same flipper bar. Only changes in accommodative facility of the right eye were analyzed.

Negative relative accommodation (NRA) is defined as the accommodation relaxed when both eyes are stimulated by positive lenses while viewing a near target. Positive relative accommodation (PRA) is defined as the accommodation generated when both eyes are stimulated by negative lenses while viewing a near target.Measurements of PRA and NRA were performed by the same experienced examiner, who was masked to treatment allocation, using the same Topcon phoropter after full correction of refractive error.

Visus sine correctore (SC, also known as uncorrected visual acuity) describes the capacity of the tested eye to clearly distinguish optotypes at a standardized testing distance without any optical corrective lenses. Results are conventionally recorded in decimal or logarithmic format. All SC visual acuity assessments are conducted under identical standardized ambient conditions by the same experienced examiner with a unified standard visual acuity chart (e.g., ETDRS or Snellen chart), to ensure objectivity and consistency of all testing procedures.

Best Corrected Visual Acuity (BCVA, Latin: visus cum correctore) is defined as the maximal visual acuity achievable after full correction of the subject's ocular refractive error, including spherical and cylindrical ametropia.

All measurements are performed under standardized illumination conditions. The same masked senior examiner instructs subjects to wear fully corrective lenses prescribed via precise refraction using an auto phoropter (e.g., Topcon). Testing is conducted with standard logarithmic visual acuity charts (ETDRS or standard Snellen charts) under full refractive correction.

This testing protocol ensures visual acuity outcomes solely reflect the intrinsic function of the visual system by eliminating confounding effects from refractive errors, thereby securing accuracy and comparability of all trial data.

Intraocular pressure (IOP) refers to the pressure exerted by the intraocular contents against the inner wall of the eyeball, measured in millimeters of mercury (mmHg). It is a key physiological parameter for evaluating ocular health, particularly the risk of glaucoma.

In this study, all IOP measurements are performed under standardized conditions by the same masked senior examiner using a single calibrated non-contact tonometer. Prior to measurement, subjects' eyes are confirmed to be free of external irritation to obtain stable and reliable readings, ensuring the accuracy and validity of data for intra-group and inter-group comparisons.