Changes in the Modulation and Critical Flicker Frequency in High Myopia Patients

Summary

We found some optic nerve and ganglion cell damage in optic neuritis and glaucoma patients and also noted a critical flicker frequency (CFF) decreaae. Retinal degeneration was found in high myopia patients as well. Are there any changes in the modulation and critical flicker frequency (CFF) in high myopia patients? Could CFF and modulation transfer function (MTF) be indexes to evaluate the severity of high myopia retinopathy? Forty-six patients with high myopia (more than 8 D) were collected in our outpatient department. We used the Cyclus Flicker Fusion Meter 731 to detect modulation at all frequencies and recorded the CFF. The control group included 21 age- and sex- matched young volunteers with myopia under 2 D. The high myopia patients and normal control volunteers had no eye disease. Although there were fluctuations between examinations, this machine can calculate the data automatically and plot a smooth curve for the relation of modulation and frequencies. There was statistical significance (p<0.00 I) in CFF between high myopic (46.77 Hz) and normal (52.50 Hz) eyes. We found decreased CFF and increased modulation at all frequencies in the high myopia patients. Retinal degeneration and decreased ganglion cell layer thickness are seen with high myopia, which is compatible with our results: decreased CFF and increased modulation at all frequencies. Maybe we can use the CFF and MTF as indexes to evaluate the severity of retinal degeneration in high myopia patients.