Vision testing in atrophic macular degeneration

Correlation between color vision, visual acuity, contrast sensitivity and photostress recovery in the visually impaired: a cross-sectional study

Background

To investigate the correlation of colour vision, visual acuity, contrast sensitivity, and photostress recovery time test scores in visually impaired patients.

Materials and methods

A total of 133 subjects were enroled and 133 eyes were examined. The pathological group consisted of 76 (57.1%) males with an average age of 68.0 (SD=13.2) and 57 (42.9%) females, with an average age of 68.1 (SD=15.2), Mann-Whitney U test was used to evaluate the differences in K-colour tests, HRR, visual acuity, Contrast Sensitivity test and photostress recovery time test between two different groups of severity.

Results

Correlations were found among colour vision tests, visual acuity, contrast sensitivity, and photostress recovery time scores in eyes with age-related macular degeneration, with diabetic retinopathy, with optic nerve diseases, and various other retinal diseases (P<0.05). In patients with moderate-visual impairments.

Conclusions

The colour vision test scores correlate with the scores of visual acuity, contrast sensitivity, and photostess recovery time test. It may be a useful clinical surrogate for functional vision.

Design of a novel smartphone-based photostress recovery time test for detecting abnormalities in the macula. A cross-sectional study

Background

The study aims to present a new smartphone-based photostress recovery time test (K-PSRT test) that measures the stimulus-specific loss of visual sensitivity, as well as the differentiation between normal from abnormal macular function. This novel test defines a new standardized photostress application as an alternative tool for incorporation into clinical practice.

Materials and methods

A total of 48 visually impaired eyes and 47 normal sighted age-matched controls eyes were enrolled in the study. The median age in subjects with impairment was 71.0 years, while the median age in normal subjects was 70.0 years. A light produced by the smartphone camera at approximately 5 cm distance, perpendicular to the eye up 10 s filled the pupil. The photostress recovery time was assessed immediately after the exposure by asking the subjects to read correctly at least three successive letters of size corresponding to the previous line of the BCVA line at a distance of 40 cm. The digital photostress testing was performed with the best-corrected visual acuity (BCVA). The patients were examined twice within 2 weeks. Correlations among the recovery times, the visual acuity, and the contrast sensitivity function as well as correlations concerning each specific ocular disease were also performed. Furthermore, correlations among technology, usability, and ease of performance in both groups were analyzed.

Results

The initial median photostress recovery time in patients with impaired eyes was 83.5 (68.5, 126.0), while in the normal individuals was 39.0 (14.0, 43.0). The median visual acuity in individuals with impairment was 0.59 logMAR (0.40, 0.90), whereas in the normal individuals was -0,06 logMAR. Test-retest reliability study was performed on 26 eyes (16 males, 10 females) for visually impaired eyes as well as on 35 normal eyes (19 males, 16 females). Concerning the reliability, the average Intraclass Correlation Coefficients (with 95% confidence intervals) ICC (95% CI) = 0,99 (0,98-1,00), indicating significant correlation between them (p < 0.01). The coefficient of repeatability for eye measurements reaches clinically acceptable levels, which is demonstrated with increased repeatability and consistency. The recovery time in patients with diabetic retinopathy was statistically significantly lower than in those with dry age-related macular degeneration (p = 0.027) and those with wet age-related macular degeneration (p = 0.032). The patient group has lower scores concerning technology, usability, and ease of performance compared to the normal.

Conclusions

This new testing modality (K-Photostress Recovery time test), is designed to be an easily implemented measurement in ophthalmic practice, and it can expand our understanding of macular function. The above findings support the usefulness of a novel reproducible photostress application as an indicator of macular pathology.

Reproducible measurement of macular light flash recovery time using a novel device can indicate the presence and worsening of macular diseases

PURPOSE

To determine the safety, sensitivity, and specificity of a novel flash photorecovery timing instrument with response verification in differentiating normal from abnormal maculae, and in detecting worsening macular disease.

METHODS

Right and left eye photorecovery times were determined at baseline and after 5 min using a xenon arc, flash filtered for infrared, ultraviolet, and visible short wavelengths, delivered through an aperture in a hand-held tube. A push-button actuated timer and flash and stopped timer when lighted numbers became visible post-flash. A numeric keypad verified responses. Normal subjects (two eyes tested, n = 144; one eye tested, n = 108) ranged in age from 15 to 84. Photorecovery times were measured in one eye of subjects with small drusen and 20/20 acuity (53-55 correct ETDRS letters; n = 57); in both eyes of subjects with dry age-related macular degeneration (AMD; n = 118); wet AMD with (n = 19) or without (n = 17) macular fluid; and eyes of diabetics with background retinopathy with (n = 19) or without (n = 17) macular retinal thickening. Once-weekly photorecovery measurements for 6 months in each eye of 10 dry AMD subjects and 10 dry diabetic maculopathy subjects provided longitudinal data.

RESULTS

Normal subjects' mean right eye recovery time was 9.6 sec (+/- 1.9 SD); left 10.8 sec (+/- 1.0 SD). Photorecovery lengthened after age 55, nearly doubling that of young subjects by age 80. Macular edema, serous macular detachment, or worsened dry AMD were accompanied by prolonged photorecovery (p < .01). When abnormal new vessels or retinal thickening appeared in three serially followed patients, photorecovery at least doubled (p < .01). In all three, photorecovery prolongation occurred without clinical symptoms. None of the 499 tested subjects reported adverse events due to the flash testing.

CONCLUSIONS

These findings support the usefulness of a reproducible light flash macular vision recovery measurement as an indicator of macular pathology and worsening disease.

Interferência mútua entre atividade visual e atividade motora em jovens e idosos

Como o envelhecimento provoca dificuldade na capacidade de dividir a atenção, este estudo visou verificar, em jovens e idosos: (1) a eventual interferência entre uma tarefa visual e uma motora; (2) se essa interferência (caso exista) ocorre de forma diferente no desempenho de jovens e idosos; (3) se as tarefas propostas têm correlação com testes validados, de seqüência alfanumérica (TMT) e de levantar e caminhar cronometrado (TLCC). A tarefa visual consistiu na verbalização do reconhecimento de duas figuras iguais ou diferentes apresentadas rapidamente. A tarefa motora consistiu na alternância de passos do chão a uma plataforma fixa de 10 cm de altura. As tarefas foram avaliadas isoladas (tarefa-simples) e associadas (tarefa-dupla) em dois grupos: 10 jovens (23±2,8 anos) e 10 idosos (68,8±8,6 anos). Na tarefa visual, os jovens fizeram menos erros que os idosos (p<0,001); nos dois grupos não houve maior número de erros na tarefa-simples quando comparada à tarefa-dupla. Na tarefa motora, os idosos tiveram pior desempenho na tarefa-dupla em relação à tarefa-simples (p=0,009). Houve correlação positiva entre o TMT e o número de alternâncias de passos (p<0,05) e correlação negativa entre o número de alternâncias de passos e o TLCC (p<0,05). A tarefa motora não interferiu na tarefa visual em jovens nem em idosos, mas a tarefa visual diminuiu a velocidade da tarefa motora dos idosos. A proposição das tarefas sem atribuir primariedade a uma ou outra permitiu detectar essas interferências.

Electrophysiological evaluation of the macular cone adaptation: VEP after photostress. A review

In the present review, the methodologies and clinical applications of the visual evoked potentials (VEPs) after photostress, will be described. Photostress induces transient VEP changes consisting of an increase in response latency and a decrease in amplitude. When serial VEP recordings are obtained at discrete time intervals (i.e., every 20 s) after bleaching, the recovery of VEP waveform can be evaluated. The time needed for the VEP to recover to the pre-bleach, baseline status (recovery time after photostress) ranges in normal subjects between 68 and 78 s. Patients with different pathologies (maculopathies, ocular hypertension and glaucoma, diabetes with or without retinopathy, multiple sclerosis with optic neuritis) showed an abnormal response after photostress (higher increase in latency and decrease in amplitude and longer recovery time) with respect to age-matched controls. Our results indicate that the VEPs after photostress represent an objective, although not specific, index of the dynamic properties of macular performance after exposure to intense light stimulation.

Electrophysiological evaluation of the macular cone system: focal electroretinography and visual evoked potentials after photostress

In this article, the methodologies and clinical applications of two electrophysiological tests, the focal electroretinogram (FERG) and the visual evoked potentials (VEPs) after photostress, are described. These techniques provide somewhat complementary results about macular function because they tap the activity of different neural substrates along the pathway of the cone system and allow evaluation of the macular function under steady-state (ie, the FERG) or dynamic (ie, the VEPs after photostress) conditions. The results obtained in patients with different macular pathologies indicate that while the FERG provides direct information about the extent and sites of macular dysfunction, the VEPs after photostress represent an objective, although not specific, index of the dynamic properties of macular performance after exposure to intense light stimulation. The combined use of both techniques appears to be promising for gaining further insights into the diagnosis and pathophysiology of macular diseases.