Dark Adaptation Time Research Articles

Relative foveal dark adaptation: a potential method for assessing macular health.

Dark adaptation measures photoreceptor recovery following intense light stimulation. Time to recovery reflects retinal function. We describe a novel method of relative foveal dark adaptation using an iPhone. Data from a small number of healthy subjects were studied to assess reproducibility, effects of age, and consider potential clinical utility. Relative foveal dark adaption was studied in 6 normal subjects across ages from 20 to 81 years and across differing testing conditions. Foveal bleaching is produced by fixating a bright white circle on an iPhone for variable times. After foveal bleaching an annular surround appears to complete a bullseye stimulus with surround initially brighter than centre. As the fovea recovers the centre regains brightness. Relative foveal dark adaptation, the time for the visual anchor to shift from surround to centre, was studied across a range of bleaching times, ages, and testing conditions. Dispersion of dark adaptation times grows with increasing age. Foveal bleaching for 30 s was as effective as longer times. Testing times with a 30 s bleach were less than 1 min. Foveal dark adaptation was reproducible within each subject and was unaffected by ambient room lighting, pupil size, and light attenuation. Repeat, immediately sequential testing was similarly reproducible except after long bleaching. This method of dark adaptation is intuitive, repeatable, and relatively unaffected by testing condition. Testing times are brief, requiring only an iPhone screen positioned at reading distance. Relative foveal dark adaptation may be a useful tool to assess macular health.

Chromatic Pupillometry as a Putative Screening Tool for Heritable Retinal Disease in Rhesus Macaques.

Non-human primates (NHPs) are useful models for human retinal disease. Chromatic pupillometry has been proposed as a noninvasive method of identifying inherited retinal diseases (IRDs) in humans; however, standard protocols employ time-consuming dark adaptation. We utilized shortened and standard dark-adaptation protocols to compare pupillary light reflex characteristics following chromatic stimulation in rhesus macaques with achromatopsia to wild-type (WT) controls with normal retinal function. Nine rhesus macaques homozygous for the p.R656Q mutation (PDE6C HOMs) and nine WT controls were evaluated using chromatic pupillometry following 1-minute versus standard 20-minute dark adaptations. The following outcomes were measured and compared between groups: pupil constriction latency, peak constriction, pupil constriction time, and constriction velocity. Pupil constriction latency was significantly longer in PDE6C HOMs with red-light (P = 0.0002) and blue-light (P = 0.04) stimulation versus WT controls. Peak constriction was significantly less in PDE6C HOMs with all light stimulation compared to WT controls (P < 0.0001). Pupil constriction time was significantly shorter in PDE6C HOMs versus WT controls with red-light (P = 0.04) and white-light (P = 0.003) stimulation. Pupil constriction velocity was significantly slower in PDE6C HOMs versus WT controls with red-light (P < 0.0001), blue-light (P < 0.0001), and white-light (P = 0.0002) stimulation. Dark adaptation time only significantly affected peak (P = 0.008) and time of pupil constriction (P = 0.02) following blue-light stimulation. Chromatic pupillometry following 1- and 20-minute dark adaptation is an effective tool for screening NHPs for achromatopsia. Rapid identification of NHPs with IRDs will provide animal research models to advance research and treatment of achromatopia in humans.

Assessment of Scotopic Function in Rod-Cone Inherited Retinal Degeneration With the Scotopic Macular Integrity Assessment.

The scotopic macular integrity assessment (S-MAIA) can perform scotopic assessment to detect localized changes to scotopic rod and cone function. This study is an exploratory investigation of the feasibility of using the S-MAIA in a rod-cone dystrophy population to identify the pattern of loss in scotopic photoreceptor function. Twenty patients diagnosed with a rod-cone dystrophy underwent visual acuity testing, full-field stimulus threshold assessment, and multiple S-MAIA tests after dark adaptation periods of 20 minutes and 45 minutes performed separately. Only right eyes were tested. Three tests were performed following a learning test. A Bland-Altman analysis was used to assess repeatability and agreement between tests after the two time periods. Spatial interpolation maps were created from the group plots to display the pattern of rod and cone loss. Learning effects took place between testing sessions 1 and 2 but not 2 and 3. Limits of agreement were larger in the patient eyes than control eyes, but within previously reported values. Using longer adaptation time of 45 minutes did not offer a significant advantage over 20 minutes. Patterns for the cyan and red sensitivities were different, indicating different patterns of loss for rods and cones. A dark adaptation time of 20 minutes before testing is sufficient for thresholding. The S-MAIA is suitable for use in patients with a logarithm of the minimum angle of resolution vision of at least 0.7 and provides a viable outcome measure for patients with rod-cone dystrophies and preserved central vision. The spatial information about scotopic function from the S-MAIA provides information about disease processes and progression. There is a need for scotopic measures for use in clinical trials. Scotopic microperimetry works well in patients with early disease, allowing the extension of recruitment criteria for novel therapies of rod-cone dystrophies.

Assessment of factual measurement times for chlorophyll-a fluorescence in rubber (Hevea brasiliensis) clones

Abstract. Cahyo AN, Murti RH, Putra ETS, Nuringtyas TR, Fabre D, Montoro P. 2021. Assessment of factual measurement times for chlorophyll-a fluorescence in rubber (Hevea brasiliensis) clones. Biodiversitas 22: 3470-3477. Chlorophyll-a fluorescence is widely used to determine the stress tolerance levels of some plant species. Measurement of chlorophyll-a fluorescence is accurate if the duration of dark adaptation is well defined and optimal Fv/Fm (maximum quantum yield of primary photochemistry/photosynthesis) is achieved. Leaf clips are usually used to darken the leaf prior to measurement. This procedure takes time and limits the use of chlorophyll-a fluorescence parameter in high-throughput screening of genetic populations. This study aimed to determine the most suitable time for the chlorophyll-a fluorescence measurement. This study was carried out on several rubbers (Hevea brasiliensis Müll. Arg.) clones and consisted of two steps. The first step was conducting the measurements at five different times at night: at 7.30, 8.00, 8.30, 9.00, and 9.30 p.m. The second step was conducting the measurements at daytime, which consisted of two factors. The first factor was the measurement time, which was divided into two categories: 7.30 a.m. and 1.30 p.m. The second factor was the duration of dark adaptation using leaf clips, which consisted of nine levels: 0, 15, 30, 45, 60, 75, 90, 105, and 120 min. Additional treatment (measurement at 9.00 p.m. without using leaf clips to darken the leaf) was used as a control. This study revealed that a dark adaptation time of two hours after the sunset was long enough for the rubber leaves chlorophyll-a fluorescence transient to be measured without using leaf clips for the dark adaptation. If the measurement is conducted by 7.30 a.m., the clone RRIM 600, GT1, and SP 217 required 15 min of dark adaptation, whereas clone PB 260 required 60 min of dark adaptation. Furthermore, measurement of chlorophyll-a fluorescence in the afternoon is not recommended due to the potentially high microclimate fluctuation.

Entrance zone length of extra-long undersea tunnels based on vision adaptation

As a new form of urban traffic, extra-long undersea tunnels have emerged as an important means of transportation to promote the development of coastal cities in recent years. Owing to the black hole effect and the special alignment at the entrance of these tunnels, the occurrence of a traffic accident can often lead to casualties and traffic paralysis. This study analyzed the main characteristics of the tunnel entrance length division methods proposed by the International Commission on Illumination (CIE), the United States, and China, and discussed the main differences between the lighting environments of extra-long undersea tunnels and ordinary highway tunnels. A real vehicle test was carried out in an extra-long undersea tunnel, and primary data, such as the driver’s pupil area and tunnel illuminance, under continuous time series were collected. The drivers’ pupil variation characteristics while driving into the tunnel during the daytime were studied, and a mathematical model of the change in the pupil area with time was constructed. In addition, a method for calculating the drivers’ dark adaptation time at the tunnel entrance was established, with the pupil area growth rate and volatility less than 15% as the indices. Based on the driver’s visual adaptation characteristics and stopping sight distance, a method for the entrance zone length of the extra-long undersea tunnel was proposed. The lengths were enhanced by 41.176, 34.513, and 20.635%, respectively, compared to those obtained using the CIE/USA/CHN standards. In view of the different calculation methods and results of the existing standards, our method overcomes the limitations of the existing methods that rely excessively on the physical and lighting characteristics of tunnels. Moreover, it considers the potential safety hazards where the main road and the ramp merge near the entrance of the tunnel, and provides a new idea for the safe length of the entrance zone from the perspective of the driver’s visual physiological response.

Evaluation of photoreceptor function in inherited retinal diseases using rod- and cone-enhanced flicker stimuli.

Clinical assessment of rod and cone photoreceptor sensitivity often involves the use of extended dark adaptation times to minimise cone involvement or the use of bright adapting backgrounds to saturate rods. In this study we examine a new rod/cone sensitivity test, which requires minimal dark adaptation. The aim was to establish whether rod/cone sensitivity losses could be measured reliably in patients with retinal diseases that selectively affect rods or cones when compared to age-matched subjects with normal vision. Flicker modulation thresholds (FMTs) were measured psychophysically, using cone- and rod-enhanced stimuli located centrally, and in four quadrants, at 5° retinal eccentricity in 20 patients (age range: 10-41years) with cone-dominated (Stargardt's disease or macular dystrophy; n=13) and rod-dominated (retinitis pigmentosa; n=7) disease. These data were compared against age-matched normals tested with identical stimuli. Across all retinal locations, cone FMTs in cone-dominated diseases (Median±IQR: 32.32±28.15% for central location) were greater than a majority (83%; 49/59) of corresponding rod FMTs (18.7±3.29%; p=0.05) and cone FMTs of controls (4.24±2.00%). Similarly, rod FMTs in rod-dominant disease (14.99±22.58%) were greater than a majority (88%; 29/39) of the corresponding cone FMTs (9.09±10.33%) (p=0.13) and rod FMT of controls (6.80±2.60 %). Cone-specific deficits were larger than rod-specific deficits in cone-dominated diseases, and vice versa in rod-dominated disease. These results suggest that the new method of assessing photoreceptor sensitivity has potential application in detecting specific rod/cone losses without the need for dark adaptation.

Simulating Human Visual Perception in Tunnel Portals

To study the characteristics of light and dark adaptation in tunnel portals, and to determine the influencing factors in light–dark vision adaptation, basic tunnel lighting and linear design data were obtained. In this study, we used a light-shielded tent to simulate the dark environment of a tunnel, observe the driver recognition time for target objects during the light–dark adaptation process, and analyze the light–dark adaptation time of human vision. Based on the experimental data, we examined the relationships between age, gender, illuminance, and light and dark adaptation times, and established a model for these relationships. The experimental results show that the dark adaptation time is generally longer than the light adaptation time. The dark adaptation time is positively related to age and exhibits a cubic relationship. There is no significant correlation between the light adaptation time and age, but the overall trend is for the light adaptation time to gradually increase with increasing age. There is no correlation between gender and light and dark adaptation times, but there is a notable correlation between light and dark adaptation times and illuminance. When the illuminance ranges from 11,000 to 13,000 lux, the light and dark adaptation times are the longest.

Determinants of Test Variability in Scotopic Microperimetry: Effects of Dark Adaptation and Test Indices.

PurposeTo test the effect of different dark adaptation conditions and reliability indices on the variability of two color scotopic microperimetry.MethodsWe analyzed data from 22 consecutive visually healthy adults. Scotopic microperimetry was performed (Macular Integrity Assessment microperimeter, CenterVue, Padua, Italy) with two wavelength stimuli, cyan (505 nm) and red (627 nm), after a dark adaptation time of 10, 20, or 30 minutes. All tests were repeated twice to measure test–retest variability with Bland–Altman plots. We also provide a method to more accurately quantify the false-positive (FP) responses based on response data (button pressing) from the device, similar to FP responses used in standard static perimetry. Data on fixation stability (95% bivariate contour ellipse area) and blind spot responses were also extracted. Their relationship with measured sensitivity (in decibels) and test–retest variability was quantified through linear mixed effect models.ResultsDark adaptation had a significant effect on the sensitivity (dB) measured with the cyan stimulus (P < 0.001), but no effect on the red stimulus. Of the three metrics, the novel FP responses showed the best association with test–retest variability and was the only predictor consistently significant for all tests (P < 0.01).ConclusionsDark adaptation protocols should be carefully standardized for scotopic testing, especially if a cyan stimulus is used. The proposed FP responses should be used to assess reliability of microperimetry examinations instead of other metrics.Translational RelevanceWe developed a method to calculate a more accurate estimate of the FP responses using data available to all researchers, generalizable to all Macular Integrity Assessment microperimeter tests.

Time-course of adaptations for electroretinography and pupillography

Cones are primarily involved in photopic vision and light adaptation. Rods are responsible for scotopic vision and dark adaptation. The typical time-courses of light and dark adaptations have been known for century. However, information regarding the minimal adaptation time for electroretinography (ERG) and pupillography would be helpful for practical applications and clinical efficiency. Therefore, we investigated the relationship between adaptation time and the parameters of ERG and pupillography. Forty-six eyes of 23 healthy women (mean age, 21.7 years) were enrolled. ERG and pupillography were tested for right and left eyes, respectively. ERG with a skin electrode was used to determine amplitude (µV) and implicit time (msec) by the records of rod-, flash-, cone-, and flicker-responses with white light (0.01–30 cd·s/m2). Infrared pupillography was used to record the pupillary response to 1-sec stimulation of red light (100 cd/m2). Cone- and flicker- (rod-, flash-, and pupil) responses were recorded after light (dark) adaptation at 1, 5, 10, 15, and 20 min. Amplitude was significantly different between 1 min and ≥5 or ≥10 min after adaptation in b-wave of cone- or rod-response, respectively. Implicit time differed significantly between 1 min and ≥5 min after adaptation with b-wave of cone- and rod-response. There were significant differences between 1 min and ≥10 or ≥5 min after dark adaptation in parameter of minimum pupil diameter or constriction rate, respectively. Consequently, light-adapted ERGs can be recorded, even in 5 min of light adaptation time without special light condition, whereas dark-adapted ERGs and pupillary response results can be obtained in 10 min or longer of dark adaptation time in complete darkness.

Experimental Study on Visual Recovery Time of Drivers after Super Glare

With the rapid growth of vehicle ownership in China, more and more roads are equipped with road monitoring fill lights to regulate the driving behavior of drivers and ensure the accuracy and efficiency of public security law enforcement. According to the statistics of relevant departments, in recent years, the number of traffic accidents caused by the flicker interference of high brightness road monitoring fill light affecting the driver's vision, has increased by 12% annually in recent years. During driving, the difference between the high brightness of the fill light and the low brightness of the normal driving environment is too large after the driver is illuminated by the fill light during driving, resulting in the driver’s visual disability. The vision of driver can be divided into two stages from being stimulated to returning to normal, which are light adaptation stage and dark adaptation stage. In the restoration process, the time of dark adaptation was significantly longer than that of light adaptation. Based on the study of various factors such as brightness of fill light, illumination time of fill light and background brightness of road that affect the driver's vision in the process of dark adaptation, this paper concludes that, firstly, in the process of driver's pupil area recovering from the minimum pupil area after stimulation to the normal environment before stimulation, the pupil area changes regularly and rapidly when the minimum pupil area recovers to 80% of the normal, while the subsequent 20% pupil area fluctuates greatly and takes a long time to recover. Secondly, with the increase of the illumination time of the fill light, the visual recovery time of the driver increases first and then decreases. Thirdly, the change of the brightness of the fill light has great impact on the longest visual recovery time of the driver. This experiment aims to provide the relevant theoretical basis for the design and the improvement of the bad effect of the road fill light on the driver's vision

ERG shrinks by 10% when reducing dark adaptation time to 10\xa0min, but only for weak flashes

PurposeTo compare dark-adapted (DA) ERG between 10, 15 and 20 min of dark adaptation (DA).MethodsIn a counterbalanced random block design, 40 healthy adult subjects were dark-adapted for 10, 15 or 20 min before we recorded ERGs to nine flash strengths from 0.001 to 10.0 cd s/m2 (dilated pupils) with a DTL-like electrode. Before and between sessions, the room was lit. Apart from choosing a wider range of stimulus strengths, and adding shorter DA times, the recordings fully complied with the ISCEV ERG Standard, namely using corneal electrodes, mydriasis and a standard DA sequence.ResultsThe a-wave amplitude was not affected by any adaptation condition. For the b-wave amplitude, effects of reduced DA time are stronger for weaker flashes: Reducing DA from 20 to 10 min had no measurable effect on the DA 3 ERG, but reduced the DA 0.01 b-wave significantly (p < 0.0001) to 87 ± 2% (mean ± SEM). The DA 0.001 b-wave (not part of the ISCEV ERG Standard) was more affected (down to 72 ± 4%). There was a small, but significant, increase, only for weak flashes, in a- and b-wave peak times for 20 compared to 10-min dark adaptation time.ConclusionReducing dark adaptation time from 20 to 10 min in normal participants has no effect on the ISCEV DA 3 and DA 10 ERG. The reduction in DA 0.01 ERGs to 87 ± 2% agrees with Hamilton and Graham (Doc Ophthalmol 133:11–19, 2016. https://doi.org/10.1007/s10633-016-9554-x) who found 90 ± 2% and with Asakawa et al. (Doc Ophthalmol 139:33–44, 2019. https://doi.org/10.1007/s10633-019-09693-8) who found 83%. Pending verification in pathophysiological states, the current results suggest that one might be able to correct for the 10% amplitude loss when gaining 10 min through shortened DA.

How do different lighting conditions affect the vision and quality of life of people with glaucoma? A systematic review.

This article is a systematic review of evidence regarding the impact of different lighting conditions on the vision and quality of life (QoL) of people with primary open-angle glaucoma (POAG). A systematic literature search was carried out using CINAHL, MEDLINE, PsycARTICLES, PsycINFO, Embase, and Ovid Nursing Database for studies: published up to April 2019; including people diagnosed with POAG; and assessing visual function or QoL in response to changing lighting/luminance levels or glare. Two researchers independently screened studies for eligibility. Data were extracted from eligible studies regarding study design, participant characteristics, outcomes, and results. Quality of included studies was critically appraised. Of 8437 studies, 56 eligible studies were included. Studies investigated the effects of lighting on the following domains among people with POAG: QoL (18/56), psychophysical measures (16/56), functional vision (10/56), activities of daily living (10/56), and qualitative findings (2/56). POAG negatively affects low-luminance contrast sensitivity, glare symptoms, and dark adaptation time and extent. In vision-related QoL questionnaires, people with POAG report problems with lighting, glare, and dark adaptation more frequently than any other domain. These problems worsen with progressing visual field loss. Early-stage POAG patients experience significantly more difficulties in low-luminance or changing lighting conditions than age-matched controls (AMCs), challenging perceptions of early-stage POAG as asymptomatic. However, performance-based studies seldom show significant differences between POAG participants and AMCs on tasks simulating daily activities under non-optimal lighting conditions. Further research with larger samples is required to optimise ambient and task-oriented lighting that can support patients' adaptation to POAG.

Adaptation time, electroretinography, and pupillography in healthy subjects.

To investigate the relationship between adaptation time and the parameters of electroretinography (ERG) and pupillography in healthy subjects. Forty-six eyes of 23 healthy women (mean age 21.7years) were enrolled. ERG and pupillography were tested in each of the right and left 23 eyes, respectively. ERG with a skin electrode was used to determine amplitude and implicit time by the records of rod-, flash-, cone-, and flicker-responses with white light (0.01-30cds/m2). Infrared pupillography was used to record the pupillary light reflex to 1-s stimulation of red light (100cd/m2). Cone- and flicker- (rod-, flash- and pupil) responses were recorded after light (dark) adaptation at 1, 5, 10, 15, and 20min. Amplitude (µV) was significantly different between 1min and ≥ 5 or ≥ 10min after adaptation in b-wave of cone- or rod-response, respectively. Implicit time (ms) differed significantly between 1min and ≥ 5min after adaptation with b-wave of cone- and rod-response. There were significant differences between 1min and ≥ 10 or ≥ 5min after dark adaptation in parameter of minimum pupil diameter (mm) or constriction rate (%), respectively. Cone-driven ERG can be recorded, even in 5min of light adaptation time without any special light condition, whereas rod-driven ERG and pupillary response results can be obtained in 10min or longer of dark adaptation time in complete darkness.

Effects of dark-adaptation time, irradiation time and nutrient level on Fv/Fm in Prorocentrum donghaiense (Dinophyceae) during different growth phases

ABSTRACTFactors that affect maximum quantum yield values of photosystem II (Fv/Fm) during exponential and stationary phases were studied in Prorocentrum donghaiense at various dark-adaptation and culture irradiation times in three nutrient treatments. Dark-adaptation and culture-irradiation times were the main factors affecting changes in Fv/Fm during exponential growth. Fv/Fm in the three nutrient treatments generally decreased over time. Significant differences in Fv/Fm were not observed in the nutrient treatments. However, at the start of stationary phase, nutrient treatment and interaction between time and nutrient treatment became the main factors that affected Fv/Fm. Longer dark-adaptation and culture-irradiation times than in the exponential phase led to greater differences in Fv/Fm as a result of different nutrient treatments. Collectively, the factors affecting measurement of Fv/Fm differed in the two growth phases. We conclude that the effects of nutrients, dark-adaptation time, and culture-irradiation time, as well as the interactions between time and nutrient treatment, should be considered before determining Fv/Fm during different growth phases.

The Impact of LED Light Color on the Dark Adaptation of Human Vision in Tunnel Entrances

For the study of dark adaptation at the entrance section of a tunnel, the effects of photopigments in rod cells and luminance can be disregarded because the luminance of this section is in the range of photopic vision. Instead, light color characteristics can be considered. This paper focused on the impact of light color, including correlated color temperature (CCT), color rendering, and spectrum, on dark adaptation at the entrance section of a tunnel. An experiment was performed based on seven kinds of high-power LEDs with different CCTs (3000–6500 K). The experimental results showed that the light color characteristics of LEDs significantly affected dark adaptation. Specifically, the better the color rendering and the lower the absence of blue light, the shorter the dark adaptation time. Among various LEDs with different CCTs, the 4000 K–4500 K LEDs have better light color characteristics and can shorten dark adaptation times. Therefore, LEDs with CCTs of 4000 K–4500 K are preferable for lighting tunnel entrances.

Optimisation of dark adaptation time required for mesopic microperimetry

BackgroundMacular Integrity Assessment (MAIA) microperimetry is increasingly used in clinical and research settings to assess point retinal sensitivity and fixation stability. Testing occurs under mesopic conditions, commonly after a period...

Dark adaptation changes in highly myopic patients

The objective of this study was to determine whether the dark adaptation time was longer in highly myopic patients than in emmetropic patients and whether there was a correlation between dark adaptation results and axial length. We conducted a retrospective study that included highly myopic patients with -6.00 dioptres or more, matched to emmetropic control patients of the same age. All patients underwent an automated adaptometry protocol that calculates the rod intercept that reflects rod-mediated dark adaptation. Axial length was measured. Colour photographs were taken to look for retinal atrophic lesions. A total of 25 highly myopic patients and 25 control patients were included. The mean rod intercept was 4.38 (±1.60) min in the myopic patients and 4.27 (±1.41) min in the control patients. This difference was not statistically significant ( p = 0.79). However, in myopic patients, the longer the axial length was, the longer the dark adaptation time was ( p = 0.0003). In addition, dark adaptation was significantly longer in myopic patients with retinal pigment epithelium atrophy than in patients without lesions ( p = 0.0398). In this study, dark adaptation time did not significantly differ between myopic patients and controls but was correlated with axial length in patients with severe myopia and was significantly longer in the presence of retinal pigment epithelium atrophic lesions.

Foveal light and dark adaptation in patients with glaucoma and healthy subjects: A case-control study.

IntroductionTo determine whether foveal light and dark adaptation are affected in glaucoma.MethodsCase-control study with 23 glaucoma patients and 51 controls. Light and dark adaptation were measured twice. After 10 minutes pre-adaptation to 0.0032 cd/m2, the background luminance increased stepwise to 320 (5 log unit step) or 10,000 cd/m2 (6.5 log unit step) for 10 minutes, then it decreased back to 0.0032 cd/m2 for 30 minutes. Foveal contrast sensitivity [CS]) as a function of time was determined using a 1.15 degree increment. Time resolution of the experiments was 30 seconds. Multiple linear regression was used to analyse the effect of glaucoma on the CS plateau and adaptation time (time to reach the plateau minus 3 dB); analyses were adjusted for age and gender.ResultsAfter light adaptation to 320 and 10,000 cd/m2, glaucoma patients had a 0.22 (P<0.001) and 0.13 (P = 0.010) log unit lower CS plateau than controls, respectively. After dark adaptation, this difference was 0.21 (P = 0.018) and 0.30 (P<0.001) log unit, respectively. Light adaptation occurred too fast to determine an accurate light adaptation time. Dark adaptation times of glaucoma patients and controls were similar, for both the 5 (7.2 versus 5.5 minutes; P = 0.10) and the 6.5 (18.2 versus 16.6 minutes; P = 0.14) log unit step.ConclusionAfter a sudden increase or decrease in luminance, the logCS adaptation curves of glaucoma patients are shifted downwards compared to the curves of healthy subjects. Glaucoma patients have a lower CS plateau than healthy subjects, for both light and dark adaptation; dark adaptation times are similar.

Dark Adaptation Time Study on Road Tunnel Daytime Lighting Based on Visual Performance Method

Visual adaptation in road tunnel daytime driving is very important to driving safety and should be paid full attention. Visual adaptation consists of light-adaptation and dark-adaptation, daytime threshold zone dark- adaptation problem when driving from outside into the tunnel is more important in tunnel lighting, current studies have described significantly distinct in the length of adaptation time. This study simulates the daytime lighting environment in the road tunnel threshold zone and records the reaction time and pupil change to many test subjects according to visual performance method in the condition of the luminance from light condition (ambient exterior luminance 4000 cd·m-2) and to dark condition (interior zone luminance 2cd·m-2), through the data analysis the length of dark adaptation time is obtained (19.8s). Study on length of effective dark adaptation time can provide length basis for road tunnel threshold zone daytime lighting design.

Relating Retinal Morphology and Function in Aging and Early to Intermediate Age-related Macular Degeneration Subjects

To evaluate relationships between age-related macular degeneration (AMD) morphology on spectral-domain optical coherence tomography (SDOCT) and visual function. Cross-sectional, observational. From the Alabama Study on Early AMD baseline visit, visual acuity, cone-mediated sensitivity, rod-mediated dark adaptation, and SDOCT were obtained in 1 eye per subject with no apparent retinal aging (n= 15), normal aging (n= 15), early AMD (n= 15), and intermediate AMD (n= 46). The volumes of retinal pigment epithelium (RPE)-drusen complex, RPE-drusen complex abnormal thinning, RPE-drusen complex abnormal thickening, and inner and outer retina were calculated in specified regions using semi-automated SDOCT segmentation. Better cone-mediated sensitivity was associated with greater RPE-drusen complex volume (r=0.34, P < .001) and less RPE-drusen complex abnormal thinning volume (r=-0.31, P= .003). Longer rod-mediated dark adaptation time, the duration for rod-mediated sensitivity to recover from photo-bleach exposure, correlated with lower RPE-drusen complex volume (r=-0.34, P= .005) and greater RPE-drusen complex abnormal thinning volume (r= 0.280, P= .023). In 19 eyes with subretinal drusenoid deposits (SDD) vs 47 eyes without SDD, rod-mediated dark adaptation time was longer (mean ± SD 13.5 ± 7.0 vs 10.2 ± 3.1minutes, P= .004), RPE-drusen complex abnormal thinning volume was greater (P < .0001), and visual acuity and cone sensitivity did not differ. Decreased function relates to structural markers on SDOCT in AMD. Because the RPE-drusen complex includes the interdigitation of outer segments and RPE apical processes and SDD in eyes with AMD, slower dark adaptation might be related to structural abnormalities of the RPE, the RPE-photoreceptor interface, or both.