Scotopic Microperimetry in the Early Diagnosis of Age-Related Macular Degeneration: Preliminary Study

Abstract

Background. Recent clinical studies have shown that, in some degenerative retinal diseases, like age-related macular degeneration (AMD), the sensitivity of the rods decreases more rapidly than the sensitivity of the cones. The aim of this study was to evaluate if there is a correlation between the presence of hard drusen at the macular level and the rod damage responsible for the reduction in scotopic retinal sensitivity in subjects at risk for AMD. Methods. The authors selected 24 subjects (14 men and 10 women) with an average age of 67.25 ± 5.7 years. Macular hard drusen were present in 50% of the subjects at the fundus oculi exam. The researchers evaluated the retinal sensitivity to light in mesopic and scotopic conditions of each subject with an MP-1 scotopic microperimeter (MP-1S). Results. In subjects with hard drusen in the fundus oculi examination, there was a statistically significant reduction in scotopic retinal sensitivity, while the mesopic retinal sensitivity was not compromised. Conclusion. This study revealed how the presence of hard drusen at the macular level is associated with a reduction in scotopic retinal sensitivity compared to a control group of healthy subjects. Retinal functionality in a scotopic setting examined with MP-1S could be useful in early diagnosis of AMD.

Scotopic Microperimetric Assessment of Rod Function in Stargardt Disease (SMART) Study: Design and Baseline Characteristics (Report No. 1)

“…From at least the beginning of the 4th decade of life, there is a progressive decline in the number of rods, at approximately 2 rods/mm 2 every day [21]. Previous studies in age-related macular degeneration (AMD) found a predilection for parafoveal loss of rods over cones in the early, nonexudative form of the disease with rod loss preceding and being more severe than cone loss both in histological examinations and psychophysical results [22].…”

Test-Retest Reliability of Scotopic and Mesopic Fundus-Controlled Perimetry Using a Modified MAIA (Macular Integrity Assessment) in Normal Eyes

“…In addition to rod loss, cone degeneration has also been observed histologically in AMD [16] . Psychophysical data in patients with early and late AMD have further underlined that rod dysfunction exceeds cone dysfunction, whereby the underlying mechanisms for the greater vulnerability of rods versus cones are largely unknown [18][19][20][21][22][23][24] . Cone-specific dysfunction is also detectable in AMD both psychophysically and with objective methods such as multifocal pupillographic perimetry or multifocal electroretinography [25][26][27][28][29] .…”

“…Later, it was demonstrated that scotopic sensitivity loss exceeded photopic sensitivity impairment in areas with increased levels of fundus autofluorescence [31] . Secondly, the no longer commercially available scanning laser ophthalmoscope (SLO 101, Rodenstock, Ottobrunn, Germany) has been used for scotopic FCP; however, only a single congress abstract has been available so far to the best of our knowledge [ While many reports on mesopic function with the MP-1 device are available, only a few reports have been published on scotopic FCP using the MP-1S [20,21,24,[32][33][34][35] . For example, we have recently shown that the presence of reticular drusen is spatially confined to outer retinal thinning and impairment of scotopic function [21] .…”

Image and Non-Image Forming Melanopsin Function in Age-Related Macular Degeneration

“…Given that AMD deficits occur parafoveally in early stages of the disease (Cheng & Vingrys 1993;Swann & LovieKitchin 1991), we conducted an analysis of the concentric rings but this did not provide additional information. Scotopic microperimetry has shown a higher sensitivity to retinal dysfunction compared with standard microperimetry in patients with drusen (Nebbioso et al 2014), possibly due to increased sensitivity to early rod photoreceptor loss in AMD. This and our study confirm the already high sensitivity of microperimetry in detecting early stages of disease (AREDS 2 and 3) (Midena et al 2007).…”

“…The difference between high and low mesopic microperimetry conditions was only 0.47 cd.m -2 . Studies that used the newer scotopic microperimeter (MP-1S) (Nebbioso et al 2014;Steinberg et al 2015) showed increased sensitivity to retinal dysfunction in AMD compared to standard mesopic microperimetry. In order to standardise testing protocols for use in clinical practice and determine the optimal light level required for maximum sensitivity, retinal function in AMD patients would need to be measured under a range of mesopic illuminations.…”