The effect of background intensity on the components of fluctuation as determined by threshold-related automated perimetry.

We studied the effect of various background intensities on the components of fluctuation by testing 20 healthy subjects on the Humphrey Field Analyzer. Our results show little difference in the total fluctuation between two low photopic background intensities similar to those commonly used on commercial perimeters: 3.02 dB for 31.5 apostilbs (asb) and 2.77 dB for 3.15 asb. However, an increase in total fluctuation (3.74 dB for 0.315 asb and 4.24 dB for 0.0315 asb) as well as in its short-term, long-term heterogeneous, and interindividual components was seen at mesopic background intensities as compared with the low photopic range. This study suggests that in healthy individuals, little difference exists in the fluctuation resulting from differences in background intensities commonly used on commercial perimeters, whereas mesopic illumination may increase the variability of threshold responses.

Static threshold variability in the peripheral visual field in normal subjects.

We assessed the variability of point-wise static threshold values and the components of fluctuation outside the central 30 degrees field in 20 normal individuals tested on the Humphrey field analyzer. We found a mean short-term fluctuation of 2.37 dB, a long-term heterogeneous fluctuation of 5.28 dB, and a long-term homogeneous fluctuation of 1.10 dB. All components of fluctuation were greatest superiorly. Point-wise variation was highest superiorly and nasally and increased with greater eccentricity from fixation in all but the temporal quadrant. Also, point-wise variation was greater between individuals than between tests in a single individual. This study suggests that outside the central 30 degrees field, changes in individual threshold measurements in the superior and nasal quadrants should be greater than those in the temporal or inferior quadrants before they can be distinguished from normal variation.

Acute frosted retinal periphlebitis.

We examined three previously healthy young patients who suffered acute visual loss associated with diffuse bilateral retinal periphlebitis. Each patient developed thick, inflammatory infiltrates surrounding all of the retinal veins, creating the appearance of frosted tree branches. Initial visual acuities ranged from 20/20 to hand motions (median, counting fingers). All patients showed rapid improvement after starting oral corticosteroid therapy, and all but one of the six affected eyes regained a visual acuity of 20/20. The clinical appearance and course of these patients matched those of a condition previously described in Japan and labeled frosted branch angiitis. The term "acute frosted retinal periphlebitis" seems to describe more accurately the clinical findings.