Purpose The effect of duration of optotype presentation on visual acuity measures has been extensively studied under photopic conditions. However, systematic data on duration dependence of acuity values under mesopic and scotopic conditions is scarce, despite being highly relevant for many visual tasks including night driving, and for clinical diagnostic applications. The present study aims to address this void. Methods We measured Landolt C acuity under photopic (90 cd/m 2), mesopic (0.7 cd/m 2), and scotopic (0.009 cd/m 2) conditions for several optotype presentation durations ranging from 0.1 to 10 s using the Freiburg Acuity and Contrast Test. Two age groups were tested (young, 18-29 years, and older, 61-74 years). Results As expected, under all luminance conditions, better acuity values were found for longer presentation durations. Photopic acuity in young participants decreased by about 0.25 log units from 0.1 to 10 s; mesopic vision mimicked the photopic visual behavior. Scotopic acuities depended more strongly on presentation duration (difference > 0.78 log units) than photopic values. There was no consistent pattern of correlation between luminance conditions across participants. We found a qualitative similarity between younger and older participants, despite higher variability among the latter and differences in absolute acuity: Photopic acuity difference (0.1 vs. 10 s) for the older participants was 0.19 log units, and scotopic difference was > 0.62 log units. Conclusion Scotopic acuity is more susceptible to changes in stimulus duration than photopic vision, with considerable interindividual variability. The latter may reflect differences in aging and sub-clinical pathophysiological processes and might have consequences for visual performance during nocturnal activities such as driving at night. Acuity testing with briefly presented scotopic stimuli might increase the usefulness of acuity assessment for tracking of the health state of the visual system.
Thrombophilia assays and taking a thorough medical history should be performed.
Therapy of neovascular age-related macular degeneration, diabetic maculopathy and macular edema after retinal vein occlusion has changed fundamentally since the introduction of anti-VEGF therapy more than 10 years ago. With the technological progress in ocular coherence tomography (OCT) functional criteria have been replaced by more morphological criteria. Contract law and administrative problems have been improved but not solved totally. In a retrospective study, 207 eyes of 157 patients who presented between January 2007 and October 2013 with neovascular age-related macular degeneration, diabetic maculopathy or macular edema after retinal vein occlusion were analyzed. Baseline visual acuity (VA) was 0.25 (median). After initial anti-VEGF upload, there was a significant increase in VA from 0.25 to 0.32 (p < 0.001). Patients with bad VA profited most (p = 0.004). Patients with more intravitreal injections had a larger increase in VA (p = 0.002). In the mainly VA-controlled group of the first years, VA decreased to 0.05 after one year and 3.49 intravitreal injections in the mean. In the OCT-controlled group of the later years, the initial increase in VA could be held after one year and 5.03 intravitreal anti-VEGF applications in the mean. There was a significant difference in the course of VA between the two groups (p = 0.001). Mean interval between indication and start of therapy was 25.34 days in the early years, and 5.40 days in the later years. Mainly VA-based criteria in the anti-VEGF therapy of the early years seem to be inferior to morphological criteria of the later years. Contract law and administrative problems have delayed the time between indication and start of therapy and, thereby, contributed to undersupply and worsening functional results.
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