Differentiating glaucoma from myopic eye is a challenge to ophthalmologists. We try to develop a new discrete Fourier transform (DFT) model for analyzing optical coherence tomography data for the circumpapillary retinal nerve fiber layer (cpRNFL), and investigate DFT as a new diagnostic tool for glaucomatous myopic eyes. The thicknesses of 12 equidistant cpRNFL points were transformed into 6 signals in the frequency domain, ranging from 1 to 6 Hz. In all 232 eyes, generalized linear model showed that 1 Hz, 2 Hz, and 4 Hz were associated with glaucoma, high myopia, and the interaction between glaucoma and high myopia. The 3 Hz signal was associated with glaucoma and high myopia exclusively. A receiver operating characteristic curve analysis of the 3 Hz signals showed areas under the curves of 0.93 (95% CI 0.90-0.96) and 0.93 (95% CI 0.88-0.98), for diagnosing glaucoma in all subjects and in the highly myopic group, respectively. The DFT model is useful to differentiate glaucoma from non-glaucomatous change and showed potential as a diagnostic tool for glaucomatous myopic eyes. Myopia is the most common ocular problem in the world. The prevalence of myopia in Asia is higher than that in Africa, Europe, or America. 1-4 Globally, it is estimated that, between the present and the year 2050, the prevalence of myopia and high myopia will continue to grow. 5 Glaucoma is one of the leading causes of blindness. It is characterized as progressive degeneration of retinal ganglion cells and thinning of the circumpapillary retinal nerve fiber layer (cpRNFL), which is the superficial layer of retina in the human eye. In recent years, optical coherence tomography (OCT) has become an important tool for detecting early anatomical changes in the cpRNFL. OCT is currently used for disease screening and progression assessments. However, in high myopic eyes, analyses of OCT images of the cpRNFL have resulted in high false-positive error rates, which makes the diagnosis of glaucoma complicated. 6,7 Clinically, visual field examination, which reveals the patient's optic nerve function, is the gold standard test to diagnose and evaluate the progression of the glaucoma. However, it takes about half an hour to perform the test in the both eyes of a patient with a whole-process accompanied technician. It was a huge burden for patients and medical system to treat glaucoma according to the visual field test. OCT investigates the structure of the optic nerve fiber layer in the eyes by non-invasive measurement, and the test takes only few minutes. In addition to the convenience, it detects the abnormality of structure changes which is more sensitive to early pathological changes than detecting the functional abnormality. Myopia, axial elongation of the eyeball, is associated with the appearance of an optic nerve crescent, disc tilt, disc torsion, and thinning of the peripapillary RNFL in some sectors, in the absence of glaucomatous change. 8-10 Those characteristic findings, which are usually associated with glaucoma, are found in high myopic ey...