Influence of ageing on visual field defects due to stable lesions.

BACKGROUND

Knowledge about the effects of ageing on visual field defects is very sparse.

METHODS

Long-term follow-up records were examined from 28 patients with light-to-moderate visual field defects remaining after surgery for pituitary tumours. All were proven free from tumour recurrences and complicating disorders. Hence, all had isolated, stable lesions of the chiasm. Follow-up periods ranged over 4-18 years (median 9). Using high-pass resolution perimetry, results were analysed from the central-most test locations in the upper temporal and upper nasal quadrants. The former typically bear the brunt of damage whereas the latter are least affected. Each patient contributed results from one eye only. Fixation stability and reproducibility were uniformly good.

RESULTS

Measuring values from the nasal quadrants remained essentially constant throughout the follow-up periods. Results from the temporal (T) quadrants were contrasted with those from the nasal (N) quadrants by calculating the T/N ratios, which were then individually regressed over follow-up periods. Hence, each patient was his or her own control. The absolute majority of regression coefficients (25 out of 28) did not significantly differ from 0.

CONCLUSION

The rate of age-related loss of neural channels appears to be identical in normal and abnormal visual field areas in subjects with stable mid-chiasmal lesions.