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Hess K, de Silva T, Grisso P, Wiley H, Thavikulwat AT, Keenan TDL, Chew EY, Cukras CA. Evaluation of Cone- and Rod-Mediated Parameters in Dark Adaptation Testing as Outcome Measures in Age-Related Macular Degeneration. Ophthalmol Retina 2022; 6:1173-1184. [PMID: 35643387 DOI: 10.1016/j.oret.2022.05.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 05/17/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
PURPOSE To investigate the suitability of 6 rod- or cone-mediated dark adaptation (DA) parameters as outcome measures for clinical trials in age-related macular degeneration (AMD), including their retest reliability, association with age and disease severity, and measurable longitudinal change over time. DESIGN Prospective, longitudinal study (Clinicaltrials.gov: NCT01352975). PARTICIPANTS A total of 191 patients with AMD and older participants followed longitudinally over 5 years. METHODS Dark adaptation testing was performed using the AdaptDx dark adaptometer with a maximum test time of 40 minutes. A 2-part exponential-linear curve was fitted to obtain values for cone decay, cone plateau, time to rod-cone break, rod intercept time (RIT), rod adaptation rate (S2), and area under the curve. Intersession retest reliability was assessed in tests performed within 2 weeks using the Bland-Altman analysis. The relationship of DA parameters with age, AMD severity, and reticular pseudodrusen (RPD) presence was evaluated using linear mixed models. MAIN OUTCOME MEASURES Retest reliability, association with disease severity, and longitudinal change of 6 DA parameters. RESULTS A total of 1329 DA curves were analyzed. Rod intercept time was the parameter that showed the greatest reliability (intraclass correlation coefficient of 0.88) and greatest association with age, AMD severity, and RPD (marginal R2 of 0.38), followed by the rod-mediated parameters area under the curve and rod-cone break. Cone plateau appeared constant at lower RIT values but increased with progressive rod dysfunction (RIT > 22.8 minutes) with a slope of 0.07 log units per 10 minutes RIT prolongation. Therefore, it might provide additional information in the advanced stages of AMD. CONCLUSIONS Age-related macular degeneration severity and RPD presence are each associated with large differences in multiple DA curve parameters. In addition, substantial differences in some parameters occur with age, even accounting for AMD severity and RPD status. This supports the 2-hit hypothesis of age and disease status on DA (and perhaps AMD pathophysiology itself). Of the DA parameters, RIT has the highest retest reliability, closest correlation with AMD severity and RPD, and largest longitudinal changes. This underscores the suitability of RIT as an outcome measure in clinical trials. The cone plateau increases only in advanced stages of kinetic rod dysfunction, indicating rod dysfunction preceding cone dysfunction and degeneration in the temporal sequence of pathology in AMD.
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Affiliation(s)
- Kristina Hess
- Unit on Clinical Investigation of Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland; Department of Ophthalmology, University Hospital Bonn, Bonn, Germany
| | - Tharindu de Silva
- Unit on Clinical Investigation of Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Peyton Grisso
- Unit on Clinical Investigation of Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Henry Wiley
- Division of Epidemiology and Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Alisa T Thavikulwat
- Division of Epidemiology and Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Tiarnan D L Keenan
- Division of Epidemiology and Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Emily Y Chew
- Division of Epidemiology and Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Catherine A Cukras
- Unit on Clinical Investigation of Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland.
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De Silva T, Hess K, Grisso P, Thavikulwat AT, Wiley H, Keenan TDL, Chew EY, Jeffrey BG, Cukras CA. Deep Learning-Based Modeling of the Dark Adaptation Curve for Robust Parameter Estimation. Transl Vis Sci Technol 2022; 11:40. [PMID: 36315120 PMCID: PMC9631495 DOI: 10.1167/tvst.11.10.40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Purpose This study investigates deep-learning (DL) sequence modeling techniques to reliably fit dark adaptation (DA) curves and estimate their key parameters in patients with age-related macular degeneration (AMD) to improve robustness and curve predictions. Methods A long-short-term memory autoencoder was used as the DL method to model the DA curve. The performance was compared against the classical nonlinear regression method using goodness-of-fit and repeatability metrics. Experiments were performed to predict the latter portion of the curve using data from early measurements. The prediction accuracy was quantified as the rod intercept time (RIT) prediction error between predicted and actual curves. Results The two models had comparable goodness-of-fit measures, with root mean squared error (RMSE; SD) = 0.11 (0.04) log-units (LU) for the classical model and RMSE = 0.13 (0.06) LU for the DL model. Repeatability of the curve fits evaluated after introduction of random perturbations, and after performing repeated testing, demonstrated superiority of the DL method, especially among parameters related to cone decay. The DL method exhibited superior ability to predict the curve and RIT using points prior to -2 LU, with 3.1 ± 3.1 minutes RIT prediction error, compared to 19.1 ± 18.6 minutes RIT error for the classical method. Conclusions The parameters obtained from the DL method demonstrated superior robustness as well as predictability of the curve. These could provide important advances in using multiple DA curve parameters to characterize AMD severity. Translational Relevance Dark adaptation is an important functional measure in studies of AMD and curve modeling using DL methods can lead to improved clinical trial end points.
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Affiliation(s)
- Tharindu De Silva
- Unit on Clinical Investigation of Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Kristina Hess
- Unit on Clinical Investigation of Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Peyton Grisso
- Unit on Clinical Investigation of Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Alisa T. Thavikulwat
- Division of Epidemiology & Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Henry Wiley
- Division of Epidemiology & Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Tiarnan D. L. Keenan
- Division of Epidemiology & Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Emily Y. Chew
- Division of Epidemiology & Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Brett G. Jeffrey
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Catherine A. Cukras
- Unit on Clinical Investigation of Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
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Pundlik S, Nigalye A, Laíns I, Mendez KM, Katz R, Kim J, Kim IK, Miller JB, Vavvas D, Miller JW, Luo G, Husain D. Area under the dark adaptation curve as a reliable alternate measure of dark adaptation response. Br J Ophthalmol 2022; 106:1450-1456. [PMID: 33888461 PMCID: PMC9815962 DOI: 10.1136/bjophthalmol-2021-318806] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 03/28/2021] [Accepted: 04/13/2021] [Indexed: 01/11/2023]
Abstract
PURPOSE Quantification of dark adaptation (DA) response using the conventional rod intercept time (RIT) requires very long testing time and may not be measurable in the presence of impairments due to diseases such as age-related macular degeneration (AMD). The goal of this study was to investigate the advantages of using area under the DA curve (AUDAC) as an alternative to the conventional parameters to quantify DA response. METHODS Data on 136 eyes (AMD: 98, normal controls: 38) from an ongoing longitudinal study on AMD were used. DA was measured using the AdaptDx 20 min protocol. AUDAC was computed from the raw DA characteristic curve at different time points, including 6.5 min and 20 min (default). The presence of AMD in the given eye was predicted using a logistic regression model within the leave-one-out cross-validation framework, with DA response as the predictor while adjusting for age and gender. The DA response variable was either the AUDAC values computed at 6.5 min (AUDAC6.5) or at 20 min (AUDAC20) cut-off, or the conventional RIT. RESULTS AUDAC6.5 was strongly correlated with AUDAC20 (β=86, p<0.001, R2=0.87). The accuracy of predicting the presence of AMD using AUDAC20 was 76%, compared with 79% when using RIT, the current gold standard. In addition, when limiting AUDAC calculation to 6.5 min cut-off, the predictive accuracy of AUDAC6.5 was 80%. CONCLUSIONS AUDAC can be a valuable measure to quantify the overall DA response and can potentially facilitate shorter testing duration while maintaining diagnostic accuracy.
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Affiliation(s)
- Shrinivas Pundlik
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Boston, Massachusetts, USA
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
| | - Archana Nigalye
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
- Retina Service, Massachusetts Eye & Ear Infirmary, Boston, Massachusetts, USA
| | - Inês Laíns
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
- Retina Service, Massachusetts Eye & Ear Infirmary, Boston, Massachusetts, USA
| | - Kevin M Mendez
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
- Retina Service, Massachusetts Eye & Ear Infirmary, Boston, Massachusetts, USA
- Channing Division of Network Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Raviv Katz
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
- Retina Service, Massachusetts Eye & Ear Infirmary, Boston, Massachusetts, USA
| | - Janice Kim
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
- Retina Service, Massachusetts Eye & Ear Infirmary, Boston, Massachusetts, USA
| | - Ivana K Kim
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
- Retina Service, Massachusetts Eye & Ear Infirmary, Boston, Massachusetts, USA
| | - John B Miller
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
- Retina Service, Massachusetts Eye & Ear Infirmary, Boston, Massachusetts, USA
| | - Demetrios Vavvas
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
- Retina Service, Massachusetts Eye & Ear Infirmary, Boston, Massachusetts, USA
| | - Joan W Miller
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
- Retina Service, Massachusetts Eye & Ear Infirmary, Boston, Massachusetts, USA
| | - Gang Luo
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Boston, Massachusetts, USA
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
| | - Deeba Husain
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
- Retina Service, Massachusetts Eye & Ear Infirmary, Boston, Massachusetts, USA
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Murray IJ, Rodrigo-Diaz E, Kelly JMF, Tahir HJ, Carden D, Patryas L, Parry NR. The role of dark adaptation in understanding early AMD. Prog Retin Eye Res 2021; 88:101015. [PMID: 34626782 DOI: 10.1016/j.preteyeres.2021.101015] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 09/24/2021] [Accepted: 09/29/2021] [Indexed: 11/27/2022]
Abstract
The main aim of the paper is to discuss current knowledge on how Age Related Macular Degeneration (AMD) affects Dark Adaptation (DA). The paper is divided into three parts. Firstly, we outline some of the molecular mechanisms that control DA. Secondly, we review the psychophysical issues and the corresponding analytical techniques. Finally, we characterise the link between slowed DA and the morphological abnormalities in early AMD. Historically, DA has been regarded as too cumbersome for widespread clinical application. Yet the technique is extremely useful; it is widely accepted that the psychophysically obtained slope of the second rod-mediated phase of the dark adaptation function is an accurate assay of photoreceptor pigment regeneration kinetics. Technological developments have prompted new ways of generating the DA curve, but analytical problems remain. A simple potential solution to these, based on the application of a novel fast mathematical algorithm, is presented. This allows the calculation of the parameters of the DA curve in real time. Improving current management of AMD will depend on identifying a satisfactory endpoint for evaluating future therapeutic strategies. This must be implemented before the onset of severe disease. Morphological changes progress too slowly to act as a satisfactory endpoint for new therapies whereas functional changes, such as those seen in DA, may have more potential in this regard. It is important to recognise, however, that the functional changes are not confined to rods and that building a mathematical model of the DA curve enables the separation of rod and cone dysfunction and allows more versatility in terms of the range of disease severity that can be monitored. Examples are presented that show how analysing the DA curve into its constituent components can improve our understanding of the morphological changes in early AMD.
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Affiliation(s)
- Ian J Murray
- Vision Science Lab., Faculty of Biology, Medicine and Health, University of Manchester, UK.
| | - Elena Rodrigo-Diaz
- Vision Science Lab., Faculty of Biology, Medicine and Health, University of Manchester, UK
| | - Jeremiah M F Kelly
- Vision Science Lab., Faculty of Biology, Medicine and Health, University of Manchester, UK
| | - Humza J Tahir
- Vision Science Lab., Faculty of Biology, Medicine and Health, University of Manchester, UK
| | - David Carden
- Vision Science Lab., Faculty of Biology, Medicine and Health, University of Manchester, UK
| | - Laura Patryas
- Vision Science Lab., Faculty of Biology, Medicine and Health, University of Manchester, UK
| | - Neil Ra Parry
- Vision Science Lab., Faculty of Biology, Medicine and Health, University of Manchester, UK; Vision Science Centre, Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
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Rodrigo-Diaz E, Tahir HJ, Kelly JM, Parry NRA, Aslam T, Murray IJ. The Light and the Dark of Early and Intermediate AMD: Cone- and Rod-Mediated Changes Are Linked to Fundus Photograph and FAF Abnormalities. Invest Ophthalmol Vis Sci 2020; 60:5070-5079. [PMID: 31801157 DOI: 10.1167/iovs.19-27971] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this paper is to describe the extent to which scotopic and photopic measures of visual function predict color fundus photograph (CFP) and fundus autofluorescence (FAF) changes in early and intermediate nonexudative AMD. Methods Sixty-nine observers were recruited: 56 AMD patients (mean age, 73 ± 12.98 years) and 13 controls (mean age, 67.77 ± 9.72 years). A nonmydriatic retinal camera was used to obtain stereo fundus photographs and FAF images were recorded with a cSLO Heidelberg Spectralis HRA+OCT. Visual acuity (VA) was measured using an Early Treatment of Diabetic Retinopathy Study chart. Contrast sensitivity (CS) was assessed with a Pelli-Robson chart. Dark adaptation (DA) curves were recorded at 3° eccentricity using a PC-based technique. Analysis of these curves yielded five parameters: cone threshold (CT), cone time constant (CC), cone-rod break (α), slope of the second rod component (S2), and rod-rod break (β). Results Both cone and rod sensitivity recovery were grossly abnormal in the patients. The rod recovery slope (S2) most accurately predicted the fundus photograph-based grade and the FAF classification (ρ = 0.61 and ρ = 0.60, respectively; both P < 0.0001). CS showed a strong association with FAF (ρ = 0.50, P < 0.0001) and with fundus photograph-based grade (ρ = 0.38, P < 0.002). There was no correlation between VA and either imaging method. Conclusions Dynamic, rod-based measures most accurately reflect the severity of early AMD. Although less specific to AMD than DA changes, static photopic abnormalities such as CS also correspond with morphologic changes. Assessment of function in early AMD should include dynamic rod- and cone-mediated measurements of sensitivity recovery.
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Affiliation(s)
- Elena Rodrigo-Diaz
- Vision Science Lab, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Humza J Tahir
- Vision Science Lab, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Jeremiah M Kelly
- Vision Science Lab, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Neil R A Parry
- Vision Science Lab, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom.,Vision Science Centre, Manchester Royal Eye Hospital, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Tariq Aslam
- Vision Science Lab, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom.,Vision Science Centre, Manchester Royal Eye Hospital, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Ian J Murray
- Vision Science Lab, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
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Abstract
PURPOSE To evaluate dark adaptation (DA) in patients with macular telangiectasia Type 2 (MacTel). METHODS After a local photobleach (4 × 4° size, 83% bleach), DA was measured using a test stimulus (2° diameter) projected at 5° eccentricity horizontal from the foveal center within the temporal parafovea. Cone plateau, rod intercept time, and rod recovery rate (S2) were calculated from the resulting DA curves. Findings were correlated with disease stages (according to Gass and Blodi), the area of ellipsoid zone loss in optical coherence tomography, and macular pigment loss ("MP-Classes 1-3"). RESULTS Fifty-nine eyes of 59 patients were compared with 18 eyes of 18 healthy controls. Dark adaptation was significantly impaired in patients with MacTel. Although differences were most pronounced for parameters indicating rod-mediated recovery, cone-mediated recovery was also decreased, yet to a lesser extent. Dark adaptation parameters were only weakly associated with disease stages and ellipsoid zone loss. A better association was found between rod-mediated recovery (S2 and rod intercept time) and macular pigment loss (Kendall's tau for rod intercept time: 0.69 and S2: -0.51; both P < 0.0001). CONCLUSION Dark adaptation is significantly impaired in patients with MacTel. Our results indicate an association of reduced macular pigment and rod dysfunction in MacTel.
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Tahir HJ, Rodrigo-Diaz E, Parry NRA, Kelly JMF, Carden D, Aslam TM, Murray IJ. Slowed Dark Adaptation in Early AMD: Dual Stimulus Reveals Scotopic and Photopic Abnormalities. Invest Ophthalmol Vis Sci 2018; 59:AMD202-AMD210. [PMID: 30398565 DOI: 10.1167/iovs.18-24227] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The recovery of visual sensitivity after a photobleach in early AMD is slowed in rods but cones also may be abnormal. The purpose of this article was to test different stimulus locations to investigate cone function and its relation to rod abnormalities. Methods Stimuli were presented at two locations, 3.0° and 5.5°, in the inferior visual field. Post photobleach dark adaptation (DA) curves from 50 early-AMD patients were compared with those from 15 healthy controls of similar age. Curves were characterized in terms of four parameters: ct, cone threshold; α, the transition point from cone to rod function; S2, the slope of the second rod-mediated component; and β, the transition from the second to the third rod-mediated component. Results There were strong location effects for the healthy group and the AMD group. Cone threshold was higher for the outer compared with the inner stimulus (P = 0.001), S2 was steeper for outer compared with inner (P < 0.001), α was shorter for outer (P = 0.004), and β was shorter for outer than inner (P = 0.002). The high variance in the patient data, particularly for α and β, explained the absence of a group*location interaction in the statistics. Conclusions The data provide a novel perspective on abnormal cone- and rod-sensitivity recovery in early dry AMD. The comparison of pairs of DA curves from different locations highlights the involvement of cones in the underlying pathology of AMD. Dynamic measures of visual function are particularly sensitive to early AMD.
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Affiliation(s)
- Humza J Tahir
- Vision Sciences Lab, Pharmacy and Optometry Section, Faculty of Biology Medicine and Health, University of Manchester, United Kingdom
| | - Elena Rodrigo-Diaz
- Vision Sciences Lab, Pharmacy and Optometry Section, Faculty of Biology Medicine and Health, University of Manchester, United Kingdom
| | - Neil R A Parry
- Centre for Hearing and Vision Research, Institute of Human Development, University of Manchester, United Kingdom.,Vision Science Centre, Manchester Royal Eye Hospital, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom.,Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Jeremiah M F Kelly
- Vision Sciences Lab, Pharmacy and Optometry Section, Faculty of Biology Medicine and Health, University of Manchester, United Kingdom
| | - David Carden
- Vision Sciences Lab, Pharmacy and Optometry Section, Faculty of Biology Medicine and Health, University of Manchester, United Kingdom
| | - Tariq M Aslam
- Vision Sciences Lab, Pharmacy and Optometry Section, Faculty of Biology Medicine and Health, University of Manchester, United Kingdom
| | - Ian J Murray
- Vision Sciences Lab, Pharmacy and Optometry Section, Faculty of Biology Medicine and Health, University of Manchester, United Kingdom
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Chen KG, Alvarez JA, Yazdanie M, Papudesu C, Wong WT, Wiley HE, Keenan TD, Chew EY, Ferris FL, Cukras CA. Longitudinal Study of Dark Adaptation as a Functional Outcome Measure for Age-Related Macular Degeneration. Ophthalmology 2018; 126:856-865. [PMID: 30278196 DOI: 10.1016/j.ophtha.2018.09.039] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 08/25/2018] [Accepted: 09/25/2018] [Indexed: 01/15/2023] Open
Abstract
PURPOSE To investigate the natural history of dark adaptation (DA) function as measured by the change in rod intercept time (RIT) over 4 years and to correlate RIT change with age-related macular degeneration (AMD) severity. DESIGN Longitudinal, single-center, observational study. PARTICIPANTS A total of 77 participants aged ≥50 years with a range of AMD severities. METHODS Participants each contributing a single study eye to the analysis were assigned into person-based AMD severity groups based on fundus characteristics (drusen, pigmentary changes, late AMD, and subretinal drusenoid deposits [SDDs]). The DA function was assessed in study eyes at baseline and 3, 6, 12, 18, 24, 36, and 48 months. Mean change in DA function over time was calculated using the slope of linear regression fits of longitudinal RIT data. Patient-reported responses on a Low Luminance Questionnaire (LLQ) were obtained at baseline and yearly. Nonparametric statistical testing was performed on all comparisons. MAIN OUTCOME MEASURE The RIT, defined as the time taken after a photobleach for visual sensitivity to recover detection of a 5×10-3 cd/m2 stimulus (a decrease of 3 log units), was monitored in study eyes over 4 years, and the mean rate of change was computed. RESULTS Longitudinal analysis of 65 study eyes followed on the standard testing protocol (mean age, 71±9.3 years; 49% were female) revealed that higher rates of RIT prolongation were correlated with AMD severity group assignment at baseline (P = 0.026) and with severity group assignments at year 4 (P = 0.0011). Study eyes that developed SDD during follow-up demonstrated higher rates of RIT prolongation relative to those that did not (P < 0.0001). Overall, higher rates of RIT prolongation were significantly correlated with greater 4-year decreases in LLQ scores (total mean score, P = 0.0032). CONCLUSIONS Longitudinal decline in DA function, which correlated with patient-reported functional deficits, was accelerated in eyes with greater AMD severity and especially in eyes with SDD both at baseline and at 4 years. The RIT prolongation as a measure of changing DA function may be a functional outcome measure in AMD clinical studies.
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Affiliation(s)
- Katherine G Chen
- National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Jason A Alvarez
- National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Mohammad Yazdanie
- National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Chandana Papudesu
- National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Wai T Wong
- National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Henry E Wiley
- National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Tiarnan D Keenan
- National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Emily Y Chew
- National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Frederick L Ferris
- National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Catherine A Cukras
- National Eye Institute, National Institutes of Health, Bethesda, Maryland.
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Owsley C, Clark ME, McGwin G. Natural History of Rod-Mediated Dark Adaptation over 2 Years in Intermediate Age-Related Macular Degeneration. Transl Vis Sci Technol 2017; 6:15. [PMID: 28593103 PMCID: PMC5461063 DOI: 10.1167/tvst.6.3.15] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 04/19/2017] [Indexed: 11/24/2022] Open
Abstract
Purpose To characterize the natural history of rod-mediated dark adaptation (RMDA) over 2 years in eyes with intermediate age-related macular degeneration (AMD). This information will be useful in understanding the potential of RMDA to serve as a functional endpoint in proof-of-concept studies and clinical trials on intermediate AMD. Methods RMDA was measured in eyes with intermediate AMD at baseline and follow-up visits over 2 years at 6, 12, 18, and 24 months. A computerized dark adaptometer measured sensitivity for targets centered at 11° on the superior vertical meridian of the retina. Rod intercept time (RIT) characterized the speed of dark adaptation and was defined as the duration (in minutes) required for sensitivity to reach a criterion level of 3.0 log units of attenuation of the stimulus. Results Mean change in RIT over 24 months for 30 eyes was 10.5 minutes (standard deviation 19.4), p < 0.0001; 73.3% of eyes had a RIT increase >1 minute, 56.7% had an increase >3 minutes, and 36.7% had an increase >6 minutes; for 26.7% RIT was unchanged (0- to 1-minute increase) or decreased. Greater increase in RIT over 24 months was associated with smoking. Conclusions RMDA slows in intermediate AMD over 2 years in most eyes. There was wide variability in RIT at both baseline and in the extent to which it increased over 24 months. A major risk factor for AMD, smoking, exacerbated RMDA slowing. Translational Relevance RMDA as assessed by RIT may be useful as a functional endpoint in proof-of-concept studies and clinical trials on intermediate AMD with 2-year designs.
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Affiliation(s)
- Cynthia Owsley
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Mark E Clark
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Gerald McGwin
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.,Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, AL, USA
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Tahir HJ, Rodrigo-Diaz E, Parry NRA, Kelly JMF, Carden D, Murray IJ. Slowed dark adaptation in older eyes; effect of location. Exp Eye Res 2016; 155:47-53. [PMID: 27890475 DOI: 10.1016/j.exer.2016.11.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 11/05/2016] [Accepted: 11/21/2016] [Indexed: 11/28/2022]
Abstract
PURPOSE The rate of rod sensitivity recovery following a photobleach is a basic measure of the integrity of the outer retina. Rods are selectively impaired in aging and many disorders of the retina, notably Age-Related Macular Degeneration (AMD). It is not known for certain whether the age-related deficit is a pan-retinal effect or if there are localised regions of impaired rod function. To address this important issue a dual arc stimulus was developed that samples sensitivity recovery in two retinal locations. METHODS Arc-shaped stimuli were presented on a black CRT screen at two locations, in the inferior visual field. Following a bleach, which was localised to the stimuli, recovery of sensitivity was measured using a modified method of adjustment technique. Neutral density filters were used to extend the luminance range of the CRT. Sensitivity recovery functions were fitted by non-linear regression to a seven-parameter model. RESULTS Pairs of sensitivity recovery functions were generated from the stimuli. The cone phases of these functions were identical. The slopes of the S2 sections of the curves were steeper for the outer stimuli for both young (p < 0.001) and older (p = 0.003) observers. The difference between the two was the same for the two groups. The α point was reached slightly earlier for the young observers and with the outer stimulus but neither of these effects reached statistical significance. The β point occurred earlier for the outer stimuli and this effect was statistically significant only for the older group. CONCLUSIONS The method places minimal demands on observers. The fact that rod sensitivity recovery is slowed in the older normal eye to the same extent in the two locations suggests that this deficit may be uniform across the retina. As there are localised losses in scotopic function in AMD, the technique is ideally suited to distinguishing impaired recovery dynamics due to normal ageing from those caused by disease.
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Affiliation(s)
- Humza J Tahir
- Faculty of Life Sciences, University of Manchester, Manchester, UK.
| | | | - Neil R A Parry
- Centre for Hearing and Vision Research, Institute of Human Development, University of Manchester, UK; Vision Science Centre, Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | | | - David Carden
- Faculty of Life Sciences, University of Manchester, Manchester, UK
| | - Ian J Murray
- Faculty of Life Sciences, University of Manchester, Manchester, UK
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Bavinger JC, Dunbar GE, Stem MS, Blachley TS, Kwark L, Farsiu S, Jackson GR, Gardner TW. The Effects of Diabetic Retinopathy and Pan-Retinal Photocoagulation on Photoreceptor Cell Function as Assessed by Dark Adaptometry. Invest Ophthalmol Vis Sci 2016; 57:208-17. [PMID: 26803796 PMCID: PMC4877135 DOI: 10.1167/iovs.15-17281] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Purpose The pathophysiology of vision loss in persons with diabetic retinopathy (DR) is complex and incompletely defined. We hypothesized that retinal pigment epithelium (RPE) and rod and cone photoreceptor dysfunction, as measured by dark adaptometry, would increase with severity of DR, and that pan-retinal photocoagulation (PRP) would exacerbate this dysfunction. Methods Dark adaptation (DA) was measured in subjects with diabetes mellitus and healthy controls. Dark adaptation was measured at 5° superior to the fovea following a flash bleach, and the data were analyzed to yield cone and rod sensitivity curves. Retinal layer thicknesses were quantified using spectral-domain optical coherence tomography (OCT). Results The sample consisted of 23 controls and 73 diabetic subjects. Subjects with moderate nonproliferative diabetic retinopathy (NPDR) exhibited significant impairment of rod recovery rate compared with control subjects (P = 0.04). Cone sensitivity was impaired in subjects with proliferative diabetic retinopathy (PDR) (type 1 diabetes mellitus [T1DM]: P = 0.0047; type 2 diabetes mellitus [T2DM]: P < 0.001). Subjects with untreated PDR compared with subjects treated with PRP exhibited similar rod recovery rates and cone sensitivities. Thinner RPE as assessed by OCT was associated with slower rod recovery and lower cone sensitivity, and thinner photoreceptor inner segment/outer segment layer was associated with lower cone sensitivity. Conclusions The results suggest that RPE and photoreceptor cell dysfunction, as assessed by cone sensitivity level and rod- and RPE-mediated dark adaptation, progresses with worsening DR, and rod recovery dysfunction occurs earlier than cone dysfunction. Function was preserved following PRP. The findings suggest multiple defects in retinoid function and provide potential points to improve visual function in persons with PDR.
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Affiliation(s)
- J Clay Bavinger
- Department of Ophthalmology and Visual Sciences W. K. Kellogg Eye Center, University of Michigan Medical School, Ann Arbor, Michigan, United States
| | - Grace E Dunbar
- Department of Ophthalmology and Visual Sciences W. K. Kellogg Eye Center, University of Michigan Medical School, Ann Arbor, Michigan, United States
| | - Maxwell S Stem
- Department of Ophthalmology and Visual Sciences W. K. Kellogg Eye Center, University of Michigan Medical School, Ann Arbor, Michigan, United States
| | - Taylor S Blachley
- Department of Ophthalmology and Visual Sciences W. K. Kellogg Eye Center, University of Michigan Medical School, Ann Arbor, Michigan, United States
| | - Leon Kwark
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States
| | - Sina Farsiu
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States 3Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States
| | | | - Thomas W Gardner
- Department of Ophthalmology and Visual Sciences W. K. Kellogg Eye Center, University of Michigan Medical School, Ann Arbor, Michigan, United States
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Gaffney AJ, Binns AM, Margrain TH. Measurement of cone dark adaptation: a comparison of four psychophysical methods. Doc Ophthalmol 2013; 128:33-41. [PMID: 24263533 DOI: 10.1007/s10633-013-9418-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 11/11/2013] [Indexed: 11/27/2022]
Abstract
PURPOSE Dark adaptometry is an important clinical tool for the diagnosis of a range of conditions, including age-related macular degeneration. In order to identify the most robust, clinically applicable technique for the measurement of cone dark adaptation, the repeatability and agreement of four psychophysical methods were assessed. METHODS Data were obtained from 31 healthy adults on two occasions, using four psychophysical methods. Participants' pupils were dilated, and 96 % of cone photopigment was bleached before threshold was monitored in the dark using one of the techniques, selected at random. This procedure was repeated for each of the remaining methods. An exponential recovery function was fitted to all threshold recovery data. The coefficient of repeatability (CoR) was calculated to assess the repeatability of the methods, and a repeated-measures analysis of variance was used to compare mean recovery parameters. RESULTS All four methods demonstrated a similar level of intersession repeatability for measurement of cone recovery, yielding CoRs between 1.18 and 1.56 min. There were no statistically significant differences in estimates of mean time constant of cone recovery (cone τ) between the four methods (p = 0.488); however, significant differences between initial and final cone thresholds were reported (p < 0.005). CONCLUSIONS All of the techniques were capable of monitoring the rapid changes in visual threshold that occur during cone dark adaptation, and the repeatability of the techniques was similar. This indicates that despite the respective advantages and disadvantages of these psychophysical techniques, all four methods would be suitable for measuring cone dark adaptation in clinical practice.
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Affiliation(s)
- Allannah J Gaffney
- School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cathays, Cardiff, CF24 4LU, UK,
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13
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The effect of pre-adapting light intensity on dark adaptation in early age-related macular degeneration. Doc Ophthalmol 2013; 127:191-9. [PMID: 23860602 DOI: 10.1007/s10633-013-9400-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 07/05/2013] [Indexed: 01/18/2023]
Abstract
BACKGROUND This study aimed to identify the pre-adapting light intensity that generated the maximum separation in the parameters of dark adaptation between participants with early age-related macular degeneration (AMD) and healthy control participants in the minimum recording time. METHODS Cone dark adaptation was monitored in 10 participants with early AMD and 10 age-matched controls after exposure to three pre-adapting light intensities, using an achromatic annulus (12° radius) centred on the fovea. Threshold recovery data were modelled, and the time constant of cone recovery (τ), final cone threshold, and time to rod-cone-break (RCB) were determined. The diagnostic potential of these parameters at all pre-adapting intensities was evaluated by constructing receiver operating characteristic (ROC) curves. RESULTS There were significant differences between those with early AMD and healthy controls in cone τ and time to RCB (p < 0.05) at all pre-adapting 'bleaching' intensities. ROC curves showed that the diagnostic potential of dark adaptometry was high following exposure to all three pre-adapting intensities, generating an area under the curve in excess of 0.87 ± 0.08 for cone τ and time to RCB for all conditions. CONCLUSIONS Dark adaptation was shown to be highly diagnostic for early AMD across a range of pre-adapting light intensities, and therefore, the lower pre-adapting intensities evaluated in this study may be used to expedite dark adaptation measurement in the clinic without compromising the integrity of the data obtained. This study reinforces the suggestion that cone and rod dark adaptation are good candidate biomarkers for early AMD.
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Patryas L, Parry NRA, Carden D, Baker DH, Kelly JMF, Aslam T, Murray IJ. Assessment of age changes and repeatability for computer-based rod dark adaptation. Graefes Arch Clin Exp Ophthalmol 2013; 251:1821-7. [PMID: 23553287 PMCID: PMC3682089 DOI: 10.1007/s00417-013-2324-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 03/07/2013] [Accepted: 03/12/2013] [Indexed: 11/28/2022] Open
Abstract
Purpose To characterize the rate of rod-mediated sensitivity decline with age using a PC-driven cathode ray tube (CRT) monitor. To provide data regarding the repeatability of the technique. Methods Dark adaptation was monitored for 30 min following a minimum 30 % pigment bleach, using a white 1° stimulus (modulated at 1 Hz), presented 11° below fixation on a CRT monitor. Thirty-three subjects with no ocular pathology and normal fundus photographs were divided into two groups: older (≥45, n = 16) and younger (<45, n = 17). Results Rod recovery was assessed using component S2 of dark adaptation. S2 was significantly slower in the older (0.19 ± 0.03 log cd.m−2.min−1) compared with the younger group (0.23 ± 0.03 log cd.m−2.min−1, t = −4.05, p < 0.0003), despite no difference in visual acuity and fundus appearance. Faster rates of S2 recovery were correlated with lower threshold at 30 min (T30) (r = −0.49). Correlation coefficients between first and second measurements for S2 and T30 were 0.49 (p < 0.009) and 0.84 (p < 0.0001) respectively. The coefficient of repeatability was 0.07 log cd.m−2.min−1 for S2 and 0.35 log cd.m−2 for T30. The coefficients of variation for S2 and T30 were 15 % and 10 % respectively. Conclusions Dark adaptation is slowed in normal ageing. CRT-based dark adaptometry is easily implemented and highly repeatable. The technique described in this article would be useful for documenting visual changes in future clinical trials assessing retinal health in the older eye with and without ocular pathology.
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Affiliation(s)
- Laura Patryas
- The Vision Centre, Carys Bannister Building, Faculty of Life Sciences, University of Manchester, Manchester, M13 9PL, UK.
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Abstract
PURPOSE Despite widespread agreement that dark adaptation is abnormal in age-related maculopathy (ARM), the optimal retinal location for detection of this deficit is unclear. We quantified the diagnostic potential of cone dark adaptation as a function of retinal eccentricity and compared this with the diagnostic potential of the time to the rod-cone-break (RCB). METHODS Cone dark adaptation was monitored after an 80% cone photopigment bleach in 10 subjects with ARM and 10 age-matched controls, using four achromatic annuli (0.5, 2, 7, and 12° radius) centered on the fovea. Threshold recovery data were modeled and the time constant of cone recovery (τ), final cone threshold, and time to RCB were determined. Diagnostic potential was evaluated by constructing receiver operating characteristic curves for these parameters. RESULTS Cone τ was significantly longer for the ARM group at 2, 7, and 12°. The greatest difference between groups was observed at 12° from fixation. At this location, the mean τ was 3.49 (±2.02) min and 0.64 (±0.38) min for ARM and control subjects, respectively (p = 0.002), and time to RCB was 17.68 (±5.37) min and 9.05 (±2.11) min for ARM and control subjects, respectively (p = 0.001). Correspondingly, receiver operating characteristic curves showed that the diagnostic potential of dark adaptometry is greatest for stimuli presented 12° from fixation; for cone τ, the area under the curve = 0.99 ± 0.02 and for time to RCB, area under the curve = 0.96 ± 0.04. CONCLUSIONS This study has shown cone-mediated dark adaptation to be significantly impaired in ARM. Our results provide compelling evidence in support of the diagnostic potential of cone dark adaptation and the use of annular stimuli at 12°. The observation that cone τ is highly diagnostic at this eccentricity is significant clinically because this parameter may be quantified within a few minutes.
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Holfort SK, Nørgaard K, Jackson GR, Hommel E, Madsbad S, Munch IC, Klemp K, Sander B, Larsen M. Retinal function in relation to improved glycaemic control in type 1 diabetes. Diabetologia 2011; 54:1853-61. [PMID: 21516521 DOI: 10.1007/s00125-011-2149-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 03/17/2011] [Indexed: 11/25/2022]
Abstract
AIMS/HYPOTHESIS To study long-term changes in retinal function in response to sustained glycaemia reduction in participants with type 1 diabetes. METHODS Prospective study using objective measures of retinal function in 17 participants with type 1 diabetes mellitus and minimal to moderate retinopathy who switched from conventional subcutaneous injection to continuous subcutaneous infusion of insulin (CSII). RESULTS Glycated haemoglobin HbA(1c) gradually decreased from 9.1% at baseline before CSII to 7.4% after 1 year on CSII. Glycaemia was markedly reduced within 1 week after initiation of CSII and remained stable thereafter. Dark adaptation and retinal electroretinographic function at 1, 4 and 16 weeks after initiation of CSII were comparable with baseline values, whereas a significant improvement in rod photoreceptor dark adaptation and dark-adapted b-wave amplitudes were seen after 52 weeks (time to rod-cone break -25% [p < 0.0001], time to a standardised rod intercept -13% [p < 0.0001], dark-adapted rod b-wave full-field amplitude +15% [p = 0.0125], standard combined rod-cone b-wave amplitude +8% [p = 0.049]). No detectable change was observed in cone adaptation, electroretinographic cone function or retinopathy. CONCLUSIONS/INTERPRETATION After initiation of CSII, the retinal visual pathway of the rods improved with a delay of more than 4 months, over a time scale comparable with the duration of the diabetic retinopathy early worsening response to sustained glycaemia reduction. This indicates that glycaemia has a long-term effect on the disposition of functional capacity in the retinal visual pathway of rod photoreceptors, the cells that appear to be driving the development of diabetic retinopathy.
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Affiliation(s)
- S K Holfort
- Department of Ophthalmology, Glostrup Hospital, Nordre Ringvej 57, 2600 Glostrup, Denmark.
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Clark ME, McGwin G, Neely D, Feist R, Mason JO, Thomley M, White MF, Ozaydin B, Girkin CA, Owsley C. Association between retinal thickness measured by spectral-domain optical coherence tomography (OCT) and rod-mediated dark adaptation in non-exudative age-related maculopathy. Br J Ophthalmol 2011; 95:1427-32. [PMID: 21289019 DOI: 10.1136/bjo.2010.190355] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIM To examine associations between retinal thickness and rod-mediated dark adaptation in older adults with non-exudative age-related maculopathy (ARM) or normal macular health. METHODS A cross-sectional study was conducted with 74 adults ≥ 50 years old from the comprehensive ophthalmology and retina services of an academic eye centre. ARM presence and disease severity in the enrolment eye was defined by the masked grading of stereofundus photos using the Clinical Age-Related Maculopathy grading system. High-definition, spectral-domain optical coherence tomography was used to estimate retinal thickness in a grid of regions in the macula. Rod-mediated dark adaptation, recovery of light sensitivity after a photo-bleach, was measured over a 20-min period for a 500 nm target presented at 5° on the inferior vertical meridian. Main outcomes of interest were retinal thickness in the macula (μm) and parameters of rod-mediated dark adaptation (second slope, third slope, average sensitivity, final sensitivity). RESULTS In non-exudative disease retinal thickness was decreased in greater disease severity; thinner retina was associated with reductions in average and final rod-mediated sensitivity even after adjustment for age and visual acuity. CONCLUSIONS Impairment in rod-mediated dark adaptation in non-exudative ARM is associated with macular thinning.
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Affiliation(s)
- Mark E Clark
- Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, AL 35294-0009, USA
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Dark adaptation during transient hyperglycemia in type 2 diabetes. Exp Eye Res 2010; 91:710-4. [DOI: 10.1016/j.exer.2010.08.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 08/12/2010] [Accepted: 08/14/2010] [Indexed: 01/29/2023]
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Owsley C, McGwin G, Jackson GR, Kallies K, Clark M. Cone- and rod-mediated dark adaptation impairment in age-related maculopathy. Ophthalmology 2007; 114:1728-35. [PMID: 17822978 DOI: 10.1016/j.ophtha.2006.12.023] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Revised: 12/15/2006] [Accepted: 12/20/2006] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE To examine impairment in cone- versus rod-mediated dark adaptation in the parafovea of persons with age-related maculopathy (ARM). DESIGN Cross-sectional. PARTICIPANTS Older adults with ARM at various severity levels from early to advanced (n = 83) and in good retinal health (n = 43), as determined by stereo fundus photographs evaluated with the Age-Related Eye Disease Study severity scale. METHODS Dark adaptation, both cone- and rod-mediated components, was measured with a modified Humphrey Field Analyzer using a target located 12 degrees in the inferior visual field on the vertical meridian, after exposure to a 98% bleach. Information was collected on self-reported problems for activities at night or under dim illumination (Low Luminance Questionnaire [LLQ]) and for activities during daytime conditions (modified National Eye Institute Visual Function Questionnaire [NEI VFQ]). MAIN OUTCOME MEASURES Cone- and rod-mediated parameters of dark adaptation. RESULTS Compared with older adults in normal retinal health, ARM patients had significant impairments in rod-mediated parameters of dark adaptation (rod-cone break, rod slope, rod sensitivity) (P<0.0001), which were increasingly abnormal as disease severity increased. Cone-mediated parameters (cone time constant and cone sensitivity) were not impaired. Low Luminance Questionnaire scores and NEI VFQ scores decreased with increased ARM severity (P = 0.0004 and P = 0.0005, respectively); the percent decrease in LLQ scores as a function of disease severity was larger in magnitude than the percent decrease in NEI VFQ scores. CONCLUSIONS Disturbances in rod-mediated but not cone-mediated dark adaptation in the parafovea at 12 degrees in the inferior field on the vertical meridian are characteristic of ARM even in its early phases.
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Affiliation(s)
- Cynthia Owsley
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294-0009, USA.
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Birch DG, Peters AY, Locke KL, Spencer R, Megarity CF, Travis GH. Visual function in patients with cone-rod dystrophy (CRD) associated with mutations in the ABCA4(ABCR) gene. Exp Eye Res 2001; 73:877-86. [PMID: 11846518 DOI: 10.1006/exer.2001.1093] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mutations in the ABCA4(ABCR) gene cause autosomal recessive Stargardt disease (STGD). ABCR mutations were identified in patients with cone-rod dystrophy (CRD) and retinitis pigmentosa (RP) by direct sequencing of all 50 exons in 40 patients. Of 10 patients with RP, one contained two ABCR mutations suggesting a compound heterozygote. This patient had a characteristic fundus appearance with attenuated vessels, pale disks and bone-spicule pigmentation. Rod electroretinograms (ERGs) were non-detectable, cone ERGs were greatly reduced in amplitude and delayed in implicit time, and visual fields were constricted to 10 degrees diameter. Eleven of 30 (37%) patients with CRD had mutations in ABCR. In general, these patients showed reduced but detectable rod ERG responses, reduced and delayed cone responses, and poor visual acuity. Rod photoresponses to high intensity flashes were of reduced maximum amplitude but showed normal values for the gain of phototransduction. Most CRD patients with mutations in ABCR showed delayed recovery of sensitivity (dark adaptation) following exposure to bright light. Pupils were also significantly smaller in these patients compared to controls at 30 min following light exposure, consistent with a persistent 'equivalent light' background due to the accumulation of a tentatively identified 'noisy' photoproduct.
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Affiliation(s)
- D G Birch
- Retina Foundation of the Southwest, 9900 North Central Expressway, Dallas, TX 75231, USA.
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Owsley C, Jackson GR, White M, Feist R, Edwards D. Delays in rod-mediated dark adaptation in early age-related maculopathy. Ophthalmology 2001; 108:1196-202. [PMID: 11425675 DOI: 10.1016/s0161-6420(01)00580-2] [Citation(s) in RCA: 175] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
OBJECTIVE To determine whether there are disturbances in the rod-mediated kinetics of dark adaptation in early age-related maculopathy (ARM). DESIGN Comparative, observational case series. PARTICIPANTS Twenty older adults with early ARM as defined by one or more large (> 63 microm) drusen, focal hyperpigmentation, or both, but no choroidal neovascularization or geographic atrophy, and 16 adults in the same age range with none of these fundus features. All participants had 20/25 visual acuity or better in the tested eye. METHODS Dark adaptation functions were measured using a modified Humphrey Field Analyzer (Zeiss Humphrey Systems, Dublin, CA) to assess the rate of rod-mediated sensitivity recovery at 12 degrees on the vertical meridian in the inferior visual field after exposure to the equivalent of a 98% bleach. Baseline (prebleach) scotopic sensitivity, visual acuity, contrast sensitivity, and photopic sensitivity were also measured. MAIN OUTCOME MEASURES Rod-cone break; second and third components of rod-mediated dark adaptation; time to baseline sensitivity; and baseline (prebleach) scotopic sensitivity. RESULTS Although their visual acuity was at least 20/25, patients with early ARM on average exhibited deficits in almost all rod-mediated parameters of dark adaptation as compared with age-similar healthy participants. For example, the rod-cone break was delayed approximately 10 minutes in early ARM patients as compared with healthy participants. Age-related maculopathy patients were more likely to fall outside the normal reference range for variables representing dark adaptation kinetics than for steady-state visual functions such as scotopic sensitivity. For example, 85% of ARM patients fell outside the normal reference range in at least one dark adaptation kinetic parameter, whereas only 25% of ARM patients fell outside the normal reference range for steady-state scotopic sensitivity. CONCLUSIONS Rod-mediated kinetic parameters of dark adaptation, which reflect the sensitivity recovery of the visual cycle, are disrupted early in ARM pathogenesis.
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Affiliation(s)
- C Owsley
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, 35294-0009, USA.
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