The different effects of aging on normal sensitivity in flicker and light-sense perimetry.

PURPOSE: To verify whether or not an accelerated loss at an older age for normal sensitivity in the central visual field is present when using the stimulus configuration of conventional white/white automated light-sense perimetry and the stimulus configuration of the automated flicker perimeter developed by one of the authors (BJL). METHODS: One hundred thirty eyes of 130 normal subjects aged 9 to 86 years were tested with the Humphrey-Field-Analyzer 640, program 30-2, and our automated flicker perimeter. In addition, short introductory learning programs were used for both techniques. All tests were performed in random order. RESULTS: Mean critical flicker fusion frequency shows a linear loss over the entire age range (r = -0.5546, P < 0.0001, slope a = -0.3820 dB/decade), whereas mean light difference sensitivity decreases only slightly up to 46 years of age (r = -0.0118, P = 0.9226, slope a = -0.0153 dB/decade), with a marked acceleration above 46 years of age (r = -0.7304, P < 0.0001, slope a = -2.0640 dB/decade). CONCLUSIONS: The absence of an accelerated loss at an older age for critical flicker fusion frequency (CFF) and the presence of such a loss for light-difference sensitivity (LDS) might be attributed to the independence of a flickering stimulus from distributing effects induced by the ocular media at an older age as proposed by one of the authors. The different age effects for CFF and LDS could also be explained by different age-related losses at different sites and for different neuronal populations throughout the visual pathways.

[Visual acuity perimetry. Detection of glaucomatous visual field defects]. / Sehschärfeperimetrie. Erfassung glaukomatöser Gesichtsfelddefekte.

50 eyes of 50 patients with different types of glaucoma (27 eyes with POAG, 14 eyes with glaucoma due to pseudoexfoliation, 8 eyes with chronic narrow-angle glaucoma, 1 eye with normal-tension glaucoma) were examined with light-sense perimetry (Humphrey-Field-Analyzer, program 30-2) and resolution perimetry according to Frisén [2-7]. As the field area tested by Frisén's ring perimeter is smaller than that of the HFA, the comparison was restricted to the area of the ring perimeter, so that 50 out of 77 test locations of the HFA were included. In addition to a quantitative comparison with statistical criteria based on age-corrected normal values, a subjective qualitative assessment was established. The quantitative comparison of all hemifields showed good agreement in 61% of eyes, the ring perimeter indicating moderately and markedly increased numbers of defects in 13% and 4% of eyes and the HFA in 18% and 4% of eyes, respectively. Qualitative comparison of the entire fields revealed good agreement in 46% of eyes, with moderately and markedly more defects in 18% and 10% for the ring perimeter and 12% and 14% for the HFA, respectively. The average time needed for examination was 6.0 +/- 1.1 min for the ring perimeter and 17.2 +/- 2.7 min for the HFA. The Global Deviation of the ring perimeter correlates linearly with the Mean Deviation of the HFA (r = 0.4824, P < 0.001).

[Comparative study of various perimetry strategies]. / Vergleichsstudie verschiedener perimetrischer Strategien.

The conventional 4/2 dB bracketing strategy with fixed steps was compared with the "dynamic step unit strategy" (DSU strategy), which is characterized by an increase of step size with defect depth. In order to analyze the intraindividual variability, 6 eyes of 3 normal subjects were tested ten times with both strategies using the PERISTAT 433. The reproducibility of the DSU strategy is better by a factor of approximately 1.1 The comparative examination of 40 eyes of 40 patients with visual field defects resulting from various pathologic conditions using both the Humphrey-Field-Analyzer (program 30-2, 4/2 dB bracketing strategy) and the Peristat 433 (DSU strategy) yielded a clear advantage (by a factor of 3) in time and a lower number of exposures for the DSU strategy. In order to analyze the reproducibility, 15 eyes of 15 patients were tested three times with both methods. The reproducibility of the DSU strategy for relative defects is worse by a factor of 1.6. Overall, the DSU strategy is substantially faster than the conventional 4/2 dB bracketing strategy; this is achieved, however, at the expense of accuracy in relative defects.

[Detection of glaucomatous visual field defects using masking campimetry]. / Erfassung glaukomatöser Gesichtsfeldveränderungen mittels der Rauschfeldkampimetrie.

A total of 100 eyes of 50 patients with ocular hypertension and glaucoma of different etiology were examined with the Humphrey-Field-Anazlyer (program 30-2) and the noise-field campimeter according to Aulhorn and Köst [1,2]. The sensitivity of noise-field campimetry vs light-sense perimetry, i.e. the percentage of eyes with an abnormal result in light-sense perimetry that were also identified as abnormal by noise-field campimetry, was 86%. The specificity, i.e. the percentage of eyes with ocular hypertension and thus by definition a normal visual field in light-sense perimetry, that were also identified as normal by noise-field campimetry, was 31%. In 12% of eyes light-sense perimetry indicated defects while the result of noise-field campimetry was normal, and in 11% of eyes noise-field campimetry showed defects though there was a normal field according to light-sense perimetry. The subjective comparison of the two methods with regard to extent and location of the field defects showed good agreement in 22% of eyes for fine noise and in 25% for coarse noise. Moderate agreement was found in 32% fine noise and 34% for coarse noise, and poor agreement, in 46% of eyes for fine noise and 41% for coarse noise. Cooperation was good in 84% of patients and was not dependent on age. Deep localized nerve fiber bundle defects are detected reliably with the noise-field campimeter. The detection of small to moderate relative defects or of generalized changes in terms of a diffuse loss, however, is unreliable. The depth of the field defects is not related to the perception of the noise field.

[Effect of faulty refraction and artificial media opacities on visual acuity perimetry]. / Einfluss von Fehlrefraktion und artifiziellen Medientrübungen auf die Sehschärfeperimetrie.

For resolution perimetry according to Frisén, 50 test locations in the central visual field are examined. Compared with conventional perimetry the test time is rather short: 5-10 min per eye. For routine application of this new perimetric technique it is important to know to what extent the threshold values are affected by refractive defocus or media opacities. To answer this, 20 eyes of 20 normal subjects were tested both with a refractive defocus (0, +1, +3, +6, +9 and +12 dpt sph) and with artificial media opacities, using occluders according to Bangerter to reduce visual acuity to average values of 0.61, 0.27, 0.14 and 0.07. The results of the present study show that even a slight refractive defocus or a slight artificial media opacity induces a marked increase in threshold values. Mean Ring score MR and defocus are quadratically correlated (MR2/defocus: r = 0.9973, p less than 0.001), and MR is linearly correlated with the Reduced Luminance Factor 1(15) (MR/1(15): r = 0.9978, p less than 0.001). Clinical evaluation of the test results of the ring perimeter thus has to take into account the influence of refractive defocus and media opacities.