학술논문
Temporal summation in myopia and its implications for the investigation of glaucoma.
Document Type
Academic Journal
Author
Stapley V; Centre for Optometry & Vision Science, Biomedical Sciences Research Institute, Ulster University, Coleraine, UK.; Anderson RS; Centre for Optometry & Vision Science, Biomedical Sciences Research Institute, Ulster University, Coleraine, UK.; National Institute for Health & Care Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK.; Redmond T; School of Optometry and Vision Sciences, Cardiff University, Cardiff, Maindy Road, UK.; Saunders K; Centre for Optometry & Vision Science, Biomedical Sciences Research Institute, Ulster University, Coleraine, UK.; Mulholland PJ; Centre for Optometry & Vision Science, Biomedical Sciences Research Institute, Ulster University, Coleraine, UK.; National Institute for Health & Care Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK.
Source
Publisher: Blackwell Publishers Country of Publication: England NLM ID: 8208839 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1475-1313 (Electronic) Linking ISSN: 02755408 NLM ISO Abbreviation: Ophthalmic Physiol Opt Subsets: MEDLINE
Subject
Language
English
Abstract
Purpose: We have previously demonstrated the upper limit of complete spatial summation (Ricco's area) to increase in non-pathological axial myopia compared to non-myopic controls. This study sought to investigate whether temporal summation is also altered in axial myopia to determine if this aspect of visual function, like in glaucoma, is influenced by reductions in retinal ganglion cell (RGC) density.
Methods: Achromatic contrast thresholds were measured for a GIII-equivalent stimulus (0.43° diameter) of six different stimulus durations (1-24 frames, 1.1-187.8 ms) in 24 participants with axial myopia (mean spherical refractive error: -4.65D, range: -1.00D to -11.25D, mean age: 34.1, range: 21-57 years) and 21 age-similar non-myopic controls (mean spherical refractive error: +0.87D, range: -0.25D to +2.00D, mean age: 31.0, range: 18-55 years). Measurements were performed at 10° eccentricity along the 90°, 180°, 270° and 360° meridians on an achromatic 10 cd/m2 background. The upper limit of complete temporal summation (critical duration, CD) was estimated from the data with iterative two-phase regression analysis.
Results: There was no significant difference (p = 0.90, Mann-Whitney U-test) in median CD between myopes (median: 44.3 ms; IQR: 26.5, 51.2) and non-myopes (median: 41.6 ms; IQR: 27.3, 48.5). Despite RGC numbers underlying the stimulus being significantly lower in the myopic group (p < 0.001), no relationship was observed between the CD estimate and co-localised RGC number (Pearson's r = -0.13, p = 0.43) or ocular length (Pearson's r = -0.08, p = 0.61).
Conclusions: Unlike spatial summation, temporal summation is unchanged in myopia. This contrasts with glaucoma where both temporal and spatial summation are altered. As such, perimetric methods optimised to test for anomalies of temporal summation may provide a means to differentiate between conditions causing only a reduced RGC density (e.g., myopia), and pathological processes causing both a reduced RGC density and RGC dysfunction (e.g., glaucoma).
(© 2023 The Authors. Ophthalmic and Physiological Optics published by John Wiley & Sons Ltd on behalf of College of Optometrists.)
Methods: Achromatic contrast thresholds were measured for a GIII-equivalent stimulus (0.43° diameter) of six different stimulus durations (1-24 frames, 1.1-187.8 ms) in 24 participants with axial myopia (mean spherical refractive error: -4.65D, range: -1.00D to -11.25D, mean age: 34.1, range: 21-57 years) and 21 age-similar non-myopic controls (mean spherical refractive error: +0.87D, range: -0.25D to +2.00D, mean age: 31.0, range: 18-55 years). Measurements were performed at 10° eccentricity along the 90°, 180°, 270° and 360° meridians on an achromatic 10 cd/m
Results: There was no significant difference (p = 0.90, Mann-Whitney U-test) in median CD between myopes (median: 44.3 ms; IQR: 26.5, 51.2) and non-myopes (median: 41.6 ms; IQR: 27.3, 48.5). Despite RGC numbers underlying the stimulus being significantly lower in the myopic group (p < 0.001), no relationship was observed between the CD estimate and co-localised RGC number (Pearson's r = -0.13, p = 0.43) or ocular length (Pearson's r = -0.08, p = 0.61).
Conclusions: Unlike spatial summation, temporal summation is unchanged in myopia. This contrasts with glaucoma where both temporal and spatial summation are altered. As such, perimetric methods optimised to test for anomalies of temporal summation may provide a means to differentiate between conditions causing only a reduced RGC density (e.g., myopia), and pathological processes causing both a reduced RGC density and RGC dysfunction (e.g., glaucoma).
(© 2023 The Authors. Ophthalmic and Physiological Optics published by John Wiley & Sons Ltd on behalf of College of Optometrists.)