scholarly journals Fast Recovery of the Amblyopic Eye Acuity of Kittens following Brief Exposure to Total Darkness Depends on the Fellow Eye

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Donald E. Mitchell ◽  
Elise Aronitz ◽  
Philip Bobbie-Ansah ◽  
Nathan Crowder ◽  
Kevin R. Duffy
Keyword(s):  
Visual Acuity ◽  
Neural Activity ◽  
Early Life ◽  
Monocular Deprivation ◽  
Total Darkness ◽  
Visual Recovery ◽  
Fast Recovery ◽  
Fellow Eye ◽  
Neural Connections ◽  
Short Period

Recent studies conducted on kittens have revealed that the reduced visual acuity of the deprived eye following a short period of monocular deprivation imposed in early life is reversed quickly following a 10-day period spent in total darkness. This study explored the contribution of the fellow eye to the darkness-induced recovery of the acuity of the deprived eye. Upon emergence of kittens from darkness, the fellow eye was occluded for different lengths of time in order to investigate its effects on either the speed or the extent of the recovery of acuity of the deprived eye. Occlusion of the fellow eye for even a day immediately following the period spent in darkness blocked any recovery of the acuity of the deprived eye. Moreover, occlusion of the fellow eye two days after the period of darkness blocked any further visual recovery beyond that achieved in the short period when both eyes were open. The results imply that the darkness-induced recovery of the acuity of the deprived eye depends upon, and is guided by, neural activity in the mature neural connections previously established by the fellow eye.

scholarly journals Ten days of darkness causes temporary blindness during an early critical period in felines

2015 ◽  
Vol 282 (1803) ◽  
pp. 20142756 ◽  
Author(s):  
Donald E. Mitchell ◽  
Nathan A. Crowder ◽  
Kaitlyn Holman ◽  
Matthew Smithen ◽  
Kevin R. Duffy
Keyword(s):  
Visual Acuity ◽  
Visual Cortex ◽  
Visual System ◽  
Neural Activity ◽  
Critical Period ◽  
Time Course ◽  
System Development ◽  
Monocular Deprivation ◽  
Relative Ease ◽  
Visual System Development

Extended periods of darkness have long been used to study how the mammalian visual system develops in the absence of any instruction from vision. Because of the relative ease of implementation of darkness as a means to eliminate visually driven neural activity, it has usually been imposed earlier in life and for much longer periods than was the case for other manipulations of the early visual input used for study of their influences on visual system development. Recently, it was shown that following a very brief (10 days) period of darkness imposed at five weeks of age, kittens emerged blind. Although vision as assessed by measurements of visual acuity eventually recovered, the time course was very slow as it took seven weeks for visual acuity to attain normal levels. Here, we document the critical period of this remarkable vulnerability to the effects of short periods of darkness by imposing 10 days of darkness on nine normal kittens at progressively later ages. Results indicate that the period of susceptibility to darkness extends only to about 10 weeks of age, which is substantially shorter than the critical period for the effects of monocular deprivation in the primary visual cortex, which extends beyond six months of age.

scholarly journals Neovascular age-related macular degeneration: is it worthwhile treating an eye with poor visual acuity, if the visual acuity of the fellow eye is good?

Eye ◽  
2017 ◽  
Vol 31 (6) ◽  
pp. 978-980 ◽  
Author(s):  
A Rasmussen ◽  
J Fuchs ◽  
L H Hansen ◽  
M Larsen ◽  
B Sander ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Macular Degeneration ◽  
Age Related Macular Degeneration ◽  
Fellow Eye ◽  
Age Related

scholarly journals A New Dichoptic Training Strategy Leads to Better Cooperation Between the Two Eyes in Amblyopia

2020 ◽  
Vol 14 ◽  
Author(s):  
Zitian Liu ◽  
Zidong Chen ◽  
Le Gao ◽  
Manli Liu ◽  
Yiru Huang ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Contrast Sensitivity ◽  
Phase 1 ◽  
Second Phase ◽  
Fellow Eye ◽  
Training Strategy ◽  
Future Design ◽  
Before And After ◽  
Group 2 ◽  
Dichoptic Training

Recent clinical trials failed to endorse dichoptic training for amblyopia treatment. Here, we proposed an alternative training strategy that focused on reducing signal threshold contrast in the amblyopic eye under a constant and high noise contrast in the fellow eye (HNC), and compared it to a typical dichoptic strategy that aimed at increasing the tolerable noise contrast in the fellow eye (i.e., TNC strategy). We recruited 16 patients with amblyopia and divided them into two groups. Eight patients in Group 1 received the HNC training, while the other eight patients in Group 2 performed the TNC training first (Phase 1) and then crossed over to the HNC training (Phase 2). We measured contrast sensitivity functions (CSFs) separately in the amblyopic and fellow eyes when the untested eye viewed mean luminance (monocularly unmasked) or noise stimuli (dichoptically masked) before and after training at a particular frequency. The area under the log contrast sensitivity function (AULCSF) of masked and unmasked conditions, and dichoptic gain (the ratio of AULCSF of masked to unmasked condition) were calculated for each eye. We found that both dichoptic training paradigms substantially improved masked CSF, dichoptic gain, and visual acuity in the amblyopic eye. As opposed to the TNC paradigm, the HNC training produced stronger effects on masked CSFs, stereoacuity, dichoptic gain, and visual acuity in the amblyopic eye. Interestingly, the second-phase HNC training in Group 2 also induced further improvement in the masked contrast sensitivity and AULCSF in the amblyopic eye. We concluded that the HNC training strategy was more effective than the TNC training paradigm. Future design for dichoptic training should not only focus on increasing the tolerable noise contrast in the fellow eye but should also “nurture” the amblyopic eye under normal binocular viewing conditions and sustained interocular suppression.

scholarly journals Baseline Characteristics of the Fellow Eye in Patients with Neovascular Age-Related Macular Degeneration: Post Hoc Analysis of the VIEW Studies

2016 ◽  
Vol 236 (2) ◽  
pp. 95-99 ◽  
Author(s):  
Sebastian Wolf ◽  
Francesco Bandello ◽  
Anat Loewenstein ◽  
Jason Slakter ◽  
Todd Katz ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Macular Degeneration ◽  
Age Related Macular Degeneration ◽  
Fellow Eye ◽  
Post Hoc Analysis ◽  
Age Related ◽  
Intravitreal Aflibercept ◽  
Baseline Characteristics ◽  
Post Hoc ◽  
Fellow Eyes

Purpose: The aim was to describe baseline characteristics of the fellow eye of patients with neovascular age-related macular degeneration (nAMD). Methods: A pooled, post hoc analysis of patients with nAMD enrolled in the VIEW studies was carried out. The VIEW studies compared intravitreal aflibercept (monthly or every 2 months after 3 monthly injections) with monthly ranibizumab. Baseline choroidal neovascularization (CNV) status of fellow eyes and baseline best-corrected visual acuity (BCVA) and lens status of all eyes were evaluated. Additional analyses evaluated the presence of drusen and pigment in fellow eyes. Results: When comparing both eyes, baseline BCVA was worse in 23.8% of fellow eyes and in 75.2% of study eyes. Lens status of fellow eyes and study eyes was similar. Baseline visual acuity of the study eye and that of the fellow eye were not correlated. Most fellow eyes had signs of early AMD, with 34.6% (n = 843) of fellow eyes having evidence of scarring. Conclusions: In patients in the VIEW studies, most fellow eyes had evidence of AMD, highlighting the importance of examining both eyes, with close follow-up thereafter, in order to detect and treat CNV earlier as needed.

Normal Visual Recovery after Optic Neuritis Despite Significant Loss of Retinal Ganglion Cells in Patients with Multiple Sclerosis

2019 ◽  
Vol 236 (04) ◽  
pp. 425-428
Author(s):  
Mohamed Sherif ◽  
Ciara Bergin ◽  
François-Xavier Borruat
Keyword(s):  
Multiple Sclerosis ◽  
Visual Loss ◽  
Full Recovery ◽  
Retinal Ganglion ◽  
Visual Recovery ◽  
Inclusion Criteria ◽  
Fellow Eye ◽  
Significant Difference ◽  
Group 2 ◽  
Group 1

Abstract Background Optic neuritis (ON) is a frequent manifestation of demyelinating attack in multiple sclerosis (MS). Initial visual loss can vary from minimal to complete. Visual improvement occurs in about 95% of patients, some of them recovering to normal [visual acuity (VA), color vision, visual field (VF)]. We analyzed retinal ganglion cell layer (RGCL) thickness in MS patients who recovered their normal vision after ON to determine whether a relative preservation of RGCL existed in these patients. Materials and Methods We conducted a retrospective study of all patients with MS and ON examined by one of us (F. X. B.) between 2013 and 2018. Inclusion criteria were strictly unilateral ON, full recovery of vision, computerized visual field, and OCT examinations. Full recovery of vision was defined as VA ≥ 10/10, Ishihara ≥ 11/13, and VF mean defect (MD) ≤ 2.6 dB. Evaluation of RGCL was obtained with spectral domain optical coherence tomography (SD-OCT). The normal fellow eye of all patients served as the control group. Relative thinning of RGCL, expressed as percentage, was calculated by comparing results from the affected eye to the fellow eye of the same patient. Results Twenty-one patients (21 affected eyes – Group 1, 21 normal fellow eyes – Group 2) satisfying the inclusion criteria were retrieved from our database. All patients exhibited the relapsing-remitting form of MS. There were 16 women and 5 men. Mean age was 39.3 years old. There were no statistically significant differences between Group 1 and Group 2 for either VA (p = 0.3934) or Ishihara (p = 0.140), but a significant difference was found for VF MD (p = 0.0405). A markedly significant difference for RGCL thickness (p = 0.0001) was found, without any correlation with the degree of visual recovery. A subgroup of patients (n = 14) was examined at the time of initial visual loss. We correlated their results of visual function to the final RGCL thickness, and a correlation was found between either the initial VA loss or the initial VF loss and the final loss of RGCL (R2 = 0.4075 and R2 = 0.00739, respectively). Conclusions In our study, all patients with ON lost a significant amount of RGCL despite a full recovery of vision, as defined by our criteria. The percentage of RGCL loss varied from 5 – 27% and could not be correlated with any final visual indices. However, a correlation was found with the degree of initial visual loss. Despite sometimes marked RGCL loss after ON, patients with MS can recover normal visual function, according to standard clinical tests.

scholarly journals Monocular deprivation in adult mice alters visual acuity and single-unit activity

2007 ◽  
Vol 14 (4) ◽  
pp. 277-286 ◽  
Author(s):  
Q. S. Fischer ◽  
A. Graves ◽  
S. Evans ◽  
M. E. Lickey ◽  
T. A. Pham
Keyword(s):  
Visual Acuity ◽  
Unit Activity ◽  
Single Unit ◽  
Monocular Deprivation ◽  
Single Unit Activity ◽  
Adult Mice

Early-Life Organophosphate Insecticide Exposure And Visual Acuity In Infants

2015 ◽  
Vol 2015 (1) ◽  
pp. 1629
Author(s):  
Monica K Silver ◽  
Chai Ji ◽  
Bingquan Zhu ◽  
Jie Shao ◽  
Betsy Lozoff ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Early Life ◽  
Organophosphate Insecticide ◽  
Insecticide Exposure

Short periods of darkness fail to restore visual or neural plasticity in adult cats

2018 ◽  
Vol 35 ◽  
Author(s):  
KAITLYN D. HOLMAN ◽  
KEVIN R. DUFFY ◽  
DONALD E. MITCHELL
Keyword(s):  
Visual Acuity ◽  
Neural Plasticity ◽  
Early Period ◽  
Monocular Deprivation ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Soma Size ◽  
Visual Acuity Loss ◽  
Adult Cats ◽  
One Year ◽  
Dorsal Lateral Geniculate

AbstractIt has been shown that the visual acuity loss experienced by the deprived eye of kittens following an early period of monocular deprivation (MD) can be alleviated rapidly following 10 days of complete darkness when imposed even as late as 14 weeks of age. To examine whether 10 days of darkness conferred benefits at any age, we measured the extent of recovery of the visual acuity of the deprived eye following the darkness imposed on adult cats that had received the same early period of MD as used in prior experiments conducted on kittens. Parallel studies conducted on different animals examined the extent to which darkness changed the magnitude of the MD-induced laminar differences of the cell soma size and immunoreactivity for the neurofilament (NF) protein in the dorsal lateral geniculate nucleus (dLGN). The results indicated that 10 days of darkness imposed at one year of age neither alleviated the acuity loss of the deprived eye induced by an earlier period of MD nor did it decrease the concurrent lamina differences of the soma size or NF loss in the dLGN.

scholarly journals Epigenetic treatments of adult rats promote recovery from visual acuity deficits induced by long-term monocular deprivation

2010 ◽  
Vol 31 (12) ◽  
pp. 2185-2192 ◽  
Author(s):  
Davide Silingardi ◽  
Manuela Scali ◽  
Giulio Belluomini ◽  
Tommaso Pizzorusso
Keyword(s):  
Visual Acuity ◽  
Monocular Deprivation ◽  
Adult Rats
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