Cone photopigment in older subjects: decreased optical density in early age-related macular degeneration

Elsner, Ann E.; Burns, Stephen A.; Weiter, John J.

doi:10.1364/josaa.19.000215

Cited by 31 publications

(30 citation statements)

References 25 publications

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“…the foveal birefringence is due to the radial order of the photoreceptor axons. [38][39][40][41] For good visual performance, the status of the inner retina and ocular media is important as well. Only three cases in our sample presented with poor visual acuity and a regular bowtie.…”

Section: Discussionmentioning

confidence: 99%

Relationship between foveal birefringence and visual acuity in neovascular age-related macular degeneration

Weber

Elsner

Miura

et al. 2006

Eye

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Purpose To investigate the relationship between visual acuity and foveal birefringence in patients with neovascular age-related macular degeneration. Methods In total, 40 patients with choroidal neovascularization underwent macular imaging with scanning laser polarimetry. Bowtie patterns, typically seen in birefringence images of the macula, were evaluated and classified into three categories: (1) regular bowtie present; (2) bowtie present, but disrupted; and (3) no bowtie present. The relation of the bowtie appearance to the best-corrected logMAR visual acuities was tested (ANOVA). Results Mean visual acuity was best for the group that had regular bowties (mean logMAR ¼ 0.34) and differed statistically significantly from the disrupted bowtie group and no bowtie group (P ¼ 0.01 and 0.0007). Ages for the three groups did not differ (P ¼ 0.31). Conclusions Appearance of a regular bowtie indicates a substantially intact Henle fibre layer with the potential for good visual function, despite the presence of underlying pathology. Conversely, disruption or absence of a bowtie may indicate severe damage to the photoreceptors, consistent with the finding of poorer visual acuity.

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Section: Discussionmentioning

confidence: 99%

Relationship between foveal birefringence and visual acuity in neovascular age-related macular degeneration

Weber

Elsner

Miura

et al. 2006

Eye

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“…In fact, the contrary has been shown in a number of studies which report poor correlations between drusen and kinetic measures such as dark-adaptation or glare recovery. [46][47][48] Elsner and Burns 20 hypothesized that decreased photosensitivity did not imply primary damage to Bruch's membrane. They used colour match techniques and demonstrated that decreased photosensitivity of the cone photopigment was not correlated with slowed regeneration kinetics in early ARM.…”

Section: Psychophysical and Electrophysiological Function Tests In Armmentioning

confidence: 99%

“…It is still not clear whether functional deficits in early ARM measured with various psychophysical tests are primarily caused by reduced sensitivity of photoreceptors, [20][21][22][23] by postreceptoral damage 21,24,25 or by damage to other tissues involved in ARM such as the RPE/Bruch's membrane complex 10,11,26 or the choroid. [27][28][29][30][31] Knowledge of the primary retinal site affected by ARM would be helpful in targeting the application of future treatments, such as pharmaceuticals, retinal transplants, or computer chips.…”

Section: Introductionmentioning

confidence: 99%

Functional loss in early age-related maculopathy: the ischaemia postreceptoral hypothesis

Feigl

Brown

Lovie‐Kitchin

et al. 2006

Eye

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We review proposed models and psychophysical and electrophysiological tests performed in many studies for early agerelated maculopathy (ARM). We suggest that ischaemia is the trigger for impaired retinal pigment epithelium function causing imbalance of secretion of vascular growth factors, reduced disc degradation capability and reduced metabolic activity and possible inflammatory response. This results in increased deposition of cell debris, such as drusen and thickens Bruch's membrane causing even more ischaemia of the overlying neurosensory retina. The photoreceptors are more resistant to ischaemia given their proximity to the choroid. Furthermore, being 'upstream' from the inner retinal layers, they act as an oxygen sink depriving retinal layers further from the choroid. Postreceptoral cell layers and especially parts of the inner nuclear layer that are located in the watershed zone between two sources of blood supply are preferentially vulnerable to ischaemia. Based on psychophysical and electrophysiological findings we propose that most of the function impairment in early ARM starts postreceptorally.

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“…On the other hand, although the parafovea in humans is reduced in thickness with age, the foveola remains unchanged (Kanai et al, 2002) and the number of foveal cones remains stable (Curcio, 2001). Furthermore, although the amount of pigment appears to be reduced in aged patients (Elsner et al, 2002), Fortune and Johnson (2002) have suggested that changes in cone responsiveness are mainly due to pre-retinal optical factors. Thus, in human subjects, rods are susceptible to age-related degeneration, whereas cones are more stable.…”

Section: The Aging Mouse Retina As a Model System For Normal Human Agingmentioning

confidence: 99%

Structure–function analysis of rods and cones in juvenile, adult, and aged C57BL/6 and Balb/c mice

et al. 2003

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To determine whether the photoreceptors change structurally and functionally during aging, and to analyze whether pigmentation in the retinal pigment epithelium might be a contributing factor. Young, adult, and aged C57BL/6 and Balb/c mice (1, 4, and 17 months of age) were housed under a 12-h light/12-h dark cycle, with an ambient light intensity at the eye level of the mice of 85 +/- 18 lux. Scotopic single-flash and photopic-flicker electroretinograms (ERGs) after complete dark adaptation were used to assess rod and cone function, respectively. Numbers of rod photoreceptors were counted in plastic sections, and rhodopsin levels were measured using absorption difference spectrophotometry. Numbers and types of cones were determined using lectin staining in retinal flatmounts and cone-specific antibodies in radial frozen sections. Young pigmented C57BL/6 and nonpigmented Balb/c mice had similar numbers of rods. In both mouse strains, there was an overall decline in rod photoreceptor number during aging, which was more pronounced in albino mice. Rod cell numbers correlated with a drop in the overall amount of rhodopsin and a reduction in the maximum a-wave of the rod ERG. The number of short-wavelength cones was unaffected by age and pigmentation, whereas an age-related decline was observed in mid-wavelength (MWL) cones in albino, but not in pigmented mice. In contrast, MWL cone function was reduced during aging in both strains. Flicker-fusion frequency was determined to be approximately 10 Hz lower in albino animals, which is due to prolonged b-waves in these ERGs. Age-related changes were found in both photoreceptor systems, rods and cones, and in both pigmented and nonpigmented mice. However, rod photoreceptors appear to be more susceptible to both aging and the lack of pigmentation, when compared to cones. These results may help as we begin to understand certain age-related retinal diseases.

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Cone photopigment in older subjects: decreased optical density in early age-related macular degeneration

Cited by 31 publications

References 25 publications

Relationship between foveal birefringence and visual acuity in neovascular age-related macular degeneration

Relationship between foveal birefringence and visual acuity in neovascular age-related macular degeneration

Functional loss in early age-related maculopathy: the ischaemia postreceptoral hypothesis

Structure–function analysis of rods and cones in juvenile, adult, and aged C57BL/6 and Balb/c mice

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