Age‐related changes in flicker sensitivity with rod‐ and cone‐enhanced stimuli

Purpose Cone and rod photoreceptors are usually isolated using high light levels for cone vision and full dark‐adaptation, when only rods respond to light. Such methods are not ideal for clinical use. A new rod/cone flicker test has been designed to isolate and measure rod‐ and cone‐mediated signals...

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Bibliographic Details
Published in:Acta ophthalmologica (Oxford, England) England), 2019-12, Vol.97 (S263), p.n/a
Main Authors: Hathibelagal, Amithavikram R., Bharadwaj, Shrikant R., Subramanian, Ahalya, Sadler, James, Barbur, John L.
Format: Article
Language:English
Subjects:
Adaptation
Age
Aging
Dark adaptation
Diabetes mellitus
Glaucoma
Light levels
Photoreception
Photoreceptors
Retina
Spectral composition
Staircases
Thresholds
Vision
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Summary:Purpose Cone and rod photoreceptors are usually isolated using high light levels for cone vision and full dark‐adaptation, when only rods respond to light. Such methods are not ideal for clinical use. A new rod/cone flicker test has been designed to isolate and measure rod‐ and cone‐mediated signals in the absence of colour signals with one minute adaptation. Methods 118 healthy adults (Mean age ± standard deviation: 40 ± 15 years), were investigated. None of the participants had a history of or exhibited signs of ocular disease. Rod and cone thresholds were measured monocularly in central vision and in each of the four quadrants (superonasal, superotemporal, inferonasal and inferotemporal) at an eccentricity of 5°. Temporal frequencies, stimulus sizes, background luminances and spectral composition were adjusted appropriately to achieve approximately equal thresholds with ~ 10‐fold separation in sensitivity between the rod‐ and cone‐enhanced stimuli. Flicker thresholds were measured using five adaptive (two‐down, one‐up), interleaved staircases. Spectrally calibrated, ‘neutral density’ glasses were used to enable adequate control of display luminance at low levels. Results The superotemporal quadrant had the lowest mean rod and cone thresholds compared to other tested quadrants. For participants, above 50 years of age, the central rod thresholds increased 0.53% per year, whereas cone thresholds increased 0.29% per year and this decline was faster than other respective quadrants. Overall, among the locations tested, the central rod (ρ = 0.547; p < 0.005) and cone (ρ = 0.504, p 
ISSN:1755-375X
1755-3768
DOI:10.1111/j.1755-3768.2019.5143