Immanuel P Seitz1,2, Jasleen K Jolly3, M Dominik Fischer1,2,3, Matthew P Simunovic4,5,6. 1. University Eye Hospital Tübingen, Elfriede-Aulhorn Straße 7, 72076, Tübingen, Germany. 2. Institute for Ophthalmic Research, Elfriede-Aulhorn Straße 7, 72076, Tübingen, Germany. 3. Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital West Wing, University of Oxford, Oxford, OX3 9DU, UK. 4. Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital West Wing, University of Oxford, Oxford, OX3 9DU, UK. mps23@cantab.net. 5. Sydney Eye Hospital, 8 Macquarie St, Sydney, NSW, 2000, Australia. mps23@cantab.net. 6. Save Sight Institute, Discipline of Ophthalmology, University of Sydney, 8 Macquarie St, Sydney, NSW, 2000, Australia. mps23@cantab.net.
Abstract
PURPOSE: The purpose of this study was to characterise alterations in colour discrimination in a cohort of patients with choroideremia prior to gene therapy, using a test previously validated for use in patients with retinal dystrophies. METHODS: We tested 20 eyes of 10 patients with a diagnosis of choroideremia and an age-matched cohort of 10 eyes of 10 normal controls using the "Cambridge Colour Test" (CCT), in which subjects are required to distinguish the gap in a C presented in one of 4 orientations in a Stilling-type array. Colour discrimination was probed along eight axes in the CIE L*u*v* colour space, and the resulting data were plotted in the CIE 1976 chromaticity diagram and fitted with least-squares ellipses. Subsequently, we estimated the achromatic area for each subject by calculating the area of the resultant discrimination ellipse and calculated sensitivity thresholds along relevant colour confusion axes. RESULTS: Colour discrimination-as quantified by log10 of the ellipse area expressed in square 1/1000th2 units in CIE 1976-was 2.26 (range 1.82 to 2.67) for normal subjects and 3.85 (range 2.35 to 5.41) for choroideremia patients. There was a statistically significant correlation between both achromatic area and red-green colour discrimination at the CCT and BCVA, and to a lesser degree between blue colour discrimination at the CCT and BCVA. The majority of ellipses in choroideremia were aligned close to the tritan axis, and loss of sensitivity was significantly larger in the tritan direction than in the red-green. CONCLUSIONS: The majority of our patients demonstrated greater loss in tritan discrimination than in red-green colour discrimination using the CCT. There was a significant correlation between achromatic area and BCVA. In keeping with our current understanding of the machinery of colour vision, there was a significant correlation between BCVA and colour discrimination thresholds, which was stronger for red-green colour discrimination, than for tritan colour discrimination. We propose that this and similar tests of colour discrimination may prove to be suitable tools for assessing functional outcomes in gene therapy trials for choroideremia.
PURPOSE: The purpose of this study was to characterise alterations in colour discrimination in a cohort of patients with choroideremia prior to gene therapy, using a test previously validated for use in patients with retinal dystrophies. METHODS: We tested 20 eyes of 10 patients with a diagnosis of choroideremia and an age-matched cohort of 10 eyes of 10 normal controls using the "Cambridge Colour Test" (CCT), in which subjects are required to distinguish the gap in a C presented in one of 4 orientations in a Stilling-type array. Colour discrimination was probed along eight axes in the CIE L*u*v* colour space, and the resulting data were plotted in the CIE 1976 chromaticity diagram and fitted with least-squares ellipses. Subsequently, we estimated the achromatic area for each subject by calculating the area of the resultant discrimination ellipse and calculated sensitivity thresholds along relevant colour confusion axes. RESULTS: Colour discrimination-as quantified by log10 of the ellipse area expressed in square 1/1000th2 units in CIE 1976-was 2.26 (range 1.82 to 2.67) for normal subjects and 3.85 (range 2.35 to 5.41) for choroideremiapatients. There was a statistically significant correlation between both achromatic area and red-green colour discrimination at the CCT and BCVA, and to a lesser degree between blue colour discrimination at the CCT and BCVA. The majority of ellipses in choroideremia were aligned close to the tritan axis, and loss of sensitivity was significantly larger in the tritan direction than in the red-green. CONCLUSIONS: The majority of our patients demonstrated greater loss in tritan discrimination than in red-green colour discrimination using the CCT. There was a significant correlation between achromatic area and BCVA. In keeping with our current understanding of the machinery of colour vision, there was a significant correlation between BCVA and colour discrimination thresholds, which was stronger for red-green colour discrimination, than for tritan colour discrimination. We propose that this and similar tests of colour discrimination may prove to be suitable tools for assessing functional outcomes in gene therapy trials for choroideremia.
Authors: Immanuel P Seitz; Ahmad Zhour; Susanne Kohl; Pablo Llavona; Tobias Peter; Barbara Wilhelm; Eberhart Zrenner; Marius Ueffing; Karl Ulrich Bartz-Schmidt; M Dominik Fischer Journal: Graefes Arch Clin Exp Ophthalmol Date: 2015-03-07 Impact factor: 3.117
Authors: M Hayakawa; K Fujiki; Y Hotta; R Ito; J Ohki; J Ono; A Saito; K Nakayasu; A Kanai; K Ishidoh; E Kominami; K Yoshida; K C Kim; H Ohashi Journal: Ophthalmic Genet Date: 1999-06 Impact factor: 1.803
Authors: Jasleen K Jolly; Markus Groppe; Jacqueline Birks; Susan M Downes; Robert E MacLaren Journal: Am J Ophthalmol Date: 2015-06-29 Impact factor: 5.258
Authors: Thomas L Edwards; Jasleen K Jolly; Markus Groppe; Alun R Barnard; Charles L Cottriall; Tanya Tolmachova; Graeme C Black; Andrew R Webster; Andrew J Lotery; Graham E Holder; Kanmin Xue; Susan M Downes; Matthew P Simunovic; Miguel C Seabra; Robert E MacLaren Journal: N Engl J Med Date: 2016-04-27 Impact factor: 91.245
Authors: Robert E MacLaren; Markus Groppe; Alun R Barnard; Charles L Cottriall; Tanya Tolmachova; Len Seymour; K Reed Clark; Matthew J During; Frans P M Cremers; Graeme C M Black; Andrew J Lotery; Susan M Downes; Andrew R Webster; Miguel C Seabra Journal: Lancet Date: 2014-01-16 Impact factor: 79.321
Authors: Ahmed M Hagag; Andreas Mitsios; Akshay Narayan; Alessandro Abbouda; Andrew R Webster; Adam M Dubis; Mariya Moosajee Journal: Eye (Lond) Date: 2020-05-28 Impact factor: 3.775