A study of spatiotemporal visual modulation transfer function for diagnosis of early glaucoma / 眼科

ABSTRACT

At 4Hz and 16Hz temporal frequencies and at a range of 3—37.8 cycles per degree (cpd) of spatial frequency which were divide into 12 grades, an instrument with a flickering sinusoid grate was used to measure the laser retina-visual cortex spatiotemporal visual modulation transfer function (S-TMTF) in patients with glaucoma. There were 34 cases (65 eyes) with early primary open-angle glaucoma (POAG), 18 cases (31 eyes) with moderate or late glaucoma and 19 cases (37 eyes) with suspect glaucoma (SG). In 6 months. 16 patients of SG were followed. The results showed that in patients with early POAG, abnormal S-TMTF values might occur in low frequency region, the abnormal values tended to be general in the middle frequency region, and in the high frequency region all the S-TMTF values were significantly lower than that of the control. In cases with SG, lowering of S-TMTF was seen in many frequency points above 9.5 cpd, but did not found in regions below 9.5 cpd. The S-TMTF values at 16 Hz were lower than that at 4 Hz in each corresponding spatial frequency, and with aggravation of the disease, the greatest discrepancy value appeared to be shifting from high to low frequency points. In the follow-up period, an early glaucomatous visual field change occurred in a female case with ocular hypertension. It is demonstrated that the S-TMTF value is of high sensitivity for diagnosis of POAG, but it is difficult to screen the specific diagnostic frequency point and its critical value.