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Gloria L. Duque-Chica, Carolina Pelegrini Gracitelli, Ana Laura de Araujo Moura, Balázs Vince Nagy, Kallene Summer Moreira Vidal, Paula Delegrego, Augusto Paranhos Jr., Dora Fix Ventura; Losses in ipRGC function are accompanied by losses in contrast sensitivity in patients with different stages of glaucoma. Invest. Ophthalmol. Vis. Sci. 2016;57(12):4657.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate if losses in ipRGC function are accompanied by losses in the spatial contrast sensitivity function (CSF) in patients with different stages of glaucoma
104 eyes from 33 primary open angle glaucoma patients and 22 healthy controls were studied. All patients passed a complete ophthalmological examination. Glaucoma severity was graded based on visual field performance using the Hodapp-Anderson-Parrish classification into mild (31 eyes), moderate (17 eyes) or severe defects (15 eyes). Pupillary light reflex (PLR) was measured monocularly with an eye tracker (View Point, Arrington) to 1 s flashes of 470 and 630 nm light at luminances of 0, 1, 2, and 2.4 log cd/m2, presented in a Ganzfeld (Q450, Roland). Normalized peak amplitude (PA) and amplitude of the sustained response (SR) at 6-8s after the light offset were measured. CSF was measured with sinusoidal achromatic vertical gratings of 0.5, 1.0, 2.0, 5.0, 10.0 and 20.0 cpd superimposed with a spatial Gabor function. Mann-Whitney U test was used for comparison between groups.
Relative to controls, the PAs for blue and red stimuli were lower at all intensities for patients with severe glaucoma (p<0.01); at 2.0 and 2.4 log cd/m2 (p<0.01) for moderate glaucoma. In moderate glaucoma the SRs for blue and red stimuli were smaller at 2 log cd/m2 (p<0.05); in severe glaucoma for the blue stimuli at 2.4 log cd/m2 (p=0.01) and for the red stimuli at 1 and 2.4 log cd/m2 (p<0.05). Relative to the mild glaucoma group, the moderate and severe groups showed PA and SR for blue stimuli reduced at 2 and 2.4log cd/m2 (p<0.05). Relative to controls, CSF losses were found in patients with mild glaucoma at 0.5, 1.0 and 2.0 cpd, in moderate glaucoma at 1.0, 2.0, 5.0 and 10.0 cpd, and in severe glaucoma at 0.5, 1.0, 2.0 and 5.0 cpd (p<0.05). Moderate and severe glaucoma were significantly less sensitive than the mild glaucoma group for spatial frequencies at 10.0 and 20.0 cpd (p<0.05).
Glaucoma patients with moderate and severe disease had reduced melanopsin contributions to the PLR and CSF losses affecting low and high spatial frequencies. In mild glaucoma patients, only low spatial frequencies are reduced, suggesting a selective damage to the magnocellular pathway. Our results suggest that P-cell/parvocellular pathway and ipRGCs may be more preserved at the beginning of the disease.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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