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1.
J Cataract Refract Surg ; 50(7): 707-712, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38517986

RESUMEN

PURPOSE: To investigate the long-term outcomes of congenital cataract surgery performed within the first 6 months of life. SETTING: 11 ophthalmic surgical sites in Japan. DESIGN: Retrospective chart review. METHODS: Medical charts were retrospectively reviewed for 216 eyes of 121 patients. The age at surgery was 2.9 ± 1.7 months, with follow-up duration 13.0 ± 2.3 years. The cohort consisted of 83 cases with bilateral aphakia, 12 with bilateral pseudophakia, 20 with unilateral aphakia, and 6 with unilateral pseudophakia. RESULTS: Surgical intervention within the critical period of visual system development (10 weeks for bilateral and 6 weeks for unilateral cases) led to significantly better final visual acuity than surgery conducted after this time frame. The incidence of secondary glaucoma was similar between groups while the occurrence of visual axis opacification was more frequent with earlier surgery. A forward stepwise multiple regression analysis revealed that the final visual acuity was significantly associated with laterality of cataract (better outcomes in bilateral cases), phakic status (with pseudophakia outperforming aphakia), presence of systemic and ocular comorbidities, and development of secondary glaucoma. Secondary glaucoma was significantly more prevalent in aphakic eyes than pseudophakic eyes. CONCLUSIONS: In patients with genuine congenital cataract, surgery within the critical period of visual development results in better final visual acuity, albeit with an increased risk of visual axis opacification. The use of IOL with sophisticated surgical techniques shows promise even in congenital cataract surgery.


Asunto(s)
Afaquia Poscatarata , Extracción de Catarata , Catarata , Implantación de Lentes Intraoculares , Seudofaquia , Agudeza Visual , Humanos , Agudeza Visual/fisiología , Estudios Retrospectivos , Catarata/congénito , Catarata/complicaciones , Lactante , Masculino , Femenino , Seudofaquia/fisiopatología , Estudios de Seguimiento , Afaquia Poscatarata/fisiopatología , Afaquia Poscatarata/cirugía , Resultado del Tratamiento , Recién Nacido , Glaucoma/cirugía , Glaucoma/fisiopatología , Glaucoma/congénito
2.
Sci Rep ; 13(1): 21645, 2023 12 08.
Artículo en Inglés | MEDLINE | ID: mdl-38062153

RESUMEN

We assessed the 10-year postoperative outcomes of pediatric cataract patients who underwent surgery at the age of 6 years or younger. A retrospective review of medical charts was conducted for 457 eyes of 277 patients, with the age at surgery averaging 1.3 ± 1.5 years (mean ± SD) and the follow-up duration averaging 12.8 ± 2.4 years (ranging from 10 to 17 years). The cohort included 250 eyes of 125 cases with bilateral aphakia (age at surgery 0.5 ± 0.8 years), 110 eyes of 55 cases with bilateral pseudophakia (1.9 ± 1.6 years), 42 cases with unilateral aphakia (1.1 ± 1.3 years), and 55 cases with unilateral pseudophakia (2.6 ± 1.7). A forward stepwise multiple regression analysis revealed that the best-corrected visual acuity at the final visit was significantly associated with laterality of cataract (with bilateral cases showing better results compared to unilateral cases), presence of systemic comorbidities, presence of ocular comorbidities, development of glaucoma, and phakic status (with better results in the pseudophakia group than the aphakia group). The age at surgery did not significantly affect visual acuity outcomes. A multiple logistic regression analysis demonstrated that the incidence of secondary glaucoma was significantly linked to younger age at surgery, phakic status (higher in aphakic than pseudophakic eyes), and presence of systemic comorbidities. In conclusion, after pediatric cataract surgery, final visual acuity was better in patients with bilateral cataracts, those treated with an intraocular lens, and cases without systemic or ocular comorbidities and secondary glaucoma. The development of secondary glaucoma was linked to younger age at surgery, aphakic status, and presence of systemic comorbidities.


Asunto(s)
Afaquia Poscatarata , Extracción de Catarata , Catarata , Glaucoma , Humanos , Niño , Lactante , Seudofaquia , Implantación de Lentes Intraoculares/efectos adversos , Pronóstico , Afaquia Poscatarata/complicaciones , Estudios de Seguimiento , Extracción de Catarata/métodos , Catarata/epidemiología , Catarata/complicaciones , Glaucoma/complicaciones , Estudios Retrospectivos , Análisis Multivariante , Resultado del Tratamiento
3.
Jpn J Ophthalmol ; 67(6): 629-636, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37695434

RESUMEN

PURPOSE: To describe clinical presentations of acquired comitant esotropia and digital device use in children, adolescents, and young adults without neurological problems. STUDY DESIGN: Multicenter prospective observational study. METHODS: Patients with acquired comitant esotropia, without intracranial diseases aged 5-35 years at the time of visit, who were seen at pre-registered facilities within 1 year of onset were enrolled. The duration from the onset of symptoms and the time of digital device usage approximately 1 month before onset and their lifestyles were surveyed. Visual acuity, cycloplegic refraction, and strabismus angles were measured. Data were analyzed in three age groups (Child: 5-12 years, Adolescent: 13-18 years, and Young adult: 19-35 years). RESULTS: Between November 2019 and December 2021, 218 patients were enrolled from 55 facilities, and 194 patients (including 62 children, 69 adolescents, and 63 young adults) were analyzed. The child group spent the least amount of time using digital devices (children: 159; adolescents: 210; young adults: 267 min/work day, p < 0.05; (mean time in the same order below) 229, 338, 314 min/holiday, p < 0.05) and had the largest strabismus angle (mean strabismus angle at near: 30, 22, 18 PD, p < 0.01; at far: 28, 26, 21 PD, p<0.05). CONCLUSION: The clinical features of acquired comitant esotropia and hand-held digital device usage differed between children aged ≤ 12 years and older patients. This report gives the current clinical characteristics of young patients with acquired esotropia and digital device usage.


Asunto(s)
Esotropía , Estrabismo , Niño , Adolescente , Adulto Joven , Humanos , Preescolar , Adulto , Esotropía/diagnóstico , Pueblos del Este de Asia , Estrabismo/diagnóstico , Agudeza Visual , Análisis de Datos , Estudios Retrospectivos , Músculos Oculomotores , Enfermedad Aguda
4.
Transl Vis Sci Technol ; 8(5): 31, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31649830

RESUMEN

PURPOSE: To create hybrid three-dimensional (3D) models of the choroidal vasculature from swept-source optical coherence tomography (SS-OCT) angiography images and to evaluate the model's characteristics. METHODS: This study used prospective, noncomparative case series, including 21 eyes of 21 healthy individuals. The 6 × 6-mm macular area was imaged repeatedly to obtain two cube image sets. Images from structural OCT (OCT-S) and OCT angiography (OCT-A) were exported. After vessel-like structures segmentation from the inverted black and white OCT-S images and the OCT-A images, both types of images were reconstructed in a 3D model. The volumes of the outer choroid and the choroidal vessels were measured after thresholding. The similarities of the segmented choroidal vessels (between OCT-S and OCT-A) and between repeatedly acquired images were measured. RESULTS: Mean vessel volume was 2.227 mm3 (29% of the outer choroidal volume) in OCT-S and 0.848 (11%) in OCT-A when measured after removal of the choriocapillaris equivalent volume. Three percent of the vessel volume in OCT-S and 8.4% of that in OCT-A overlapped. The Dice similarity coefficient of vessel volumes in repeated images from the same individual was 0.863 in OCT-S and 0.485 in OCT-A. The ratio of vessel volume to the outer choroidal volume was invariant in OCT-S but increased in OCT-A in the eyes with long axial length. CONCLUSIONS: Hybrid 3D vascular models of the choroidal vasculature were reconstructed from OCT-S and OCT-A. The new models should prove useful for volumetric analysis of the choroid. TRANSLATIONAL RELEVANCE: Hybrid 3D models of the choroidal vasculature enable volumetric analysis and facilitate morphologic evaluation.

5.
Curr Eye Res ; 40(9): 954-61, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25330225

RESUMEN

PURPOSE: To investigate the relationship between subfoveal choroidal thickness and axial length in Japanese preschool children with hyperopic anisometropic amblyopia. METHODS: Twenty-four children between the age of 3 and 6 years exhibiting hyperopic anisometropic amblyopia were examined. Differences in spherical equivalent between the two eyes were over 1.5 D in all children. Twenty-four eyes in 12 children without anisometropia and amblyopia were examined as age-matched normal controls. Subfoveal choroidal thickness was measured by using enhanced depth imaging optical coherence tomography. Axial length was measured with noncontact optical biometer. RESULTS: The spherical equivalent ranged from +3.50 to +7.25 D in amblyopic eyes and from +0.75 to +3.50 D in fellow eyes. The subfoveal choroidal thickness was significantly greater in the amblyopic eyes than that in the fellow eyes (407.3 ± 54.2 µm versus 357.7 ± 54.3 µm, Paired t-test, p < 0.05). The axial length in the amblyopic eyes was significantly shorter than that in the fellow eyes (21.16 ± 0.64 mm versus 22.08 ± 0.72 mm, Paired t-test, p < 0.05). The mean choroidal thickness of the fellow eyes in hyperopic anisometropic amblyopia was greater than that in age matched normal children, although this difference did not reach statistical significance (326.0 ± 62.1 µm, p = 0.07). The subfoveal choroidal thickness in amblyopic children was negatively correlated with their axial length (r = -0.50, p < 0.01). CONCLUSION: The subfoveal choroidal thickness of amblyopic children abnormally increased and the thicker subfoveal choroid is mildly correlated with their shorter axial length. The anomalous subfoveal choroidal thicknesses in our amblyopic children may reflect a delay in emmetropization.


Asunto(s)
Ambliopía/diagnóstico , Anisometropía/diagnóstico , Longitud Axial del Ojo , Coroides/patología , Hiperopía/diagnóstico , Ambliopía/complicaciones , Ambliopía/fisiopatología , Anisometropía/complicaciones , Anisometropía/fisiopatología , Niño , Preescolar , Femenino , Estudios de Seguimiento , Humanos , Hiperopía/complicaciones , Hiperopía/fisiopatología , Masculino , Estudios Retrospectivos , Índice de Severidad de la Enfermedad , Tomografía de Coherencia Óptica/métodos , Agudeza Visual
6.
Clin Ophthalmol ; 8: 2013-8, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25302013

RESUMEN

PURPOSE: To elucidate Japanese trends for perioperative disinfection and antibiotic selection during cataract surgeries. METHODS: Perioperative iodine use and antibiotic prophylaxis for cataract surgery were surveyed in eight regions in Japan by mail or through interviews from February 1 to March 1, 2014. RESULTS: We surveyed 572 surgeons, of whom 386 (67%) responded. Most of the surgeons (94%) used iodine compounds before surgery for periocular skin disinfection (povidone-iodine [PI]: 79%; polyvinyl alcohol-iodine [PAI]: 15%) or conjunctival disinfection (85%; PI: 36%; PAI: 49%). Preoperative conjunctival iodine was primarily used as an eye wash (irrigation: 95%) and less often as an eye drop (5%). It was determined that 31% of surgeons waited 30 seconds or more between periocular disinfection and conjunctival disinfection. During surgery, 14% of surgeons used iodine several times, including immediately before intraocular lens insertion, and 7% used the Shimada technique (repeated iodine irrigation). Preoperative antibiotic eye drops were used by 99% of surgeons, and antibiotics were added to the irrigation bottle by 22%. The surgeons reported use of subconjunctival antibiotic injections (23%), antibiotic ointments (79%), and intracameral antibiotics (7%: 22 moxifloxacin; 6 levofloxacin). All surgeons prescribed postoperative eye drops, with 10% initiating the drops on the day of surgery. CONCLUSION: Iodine compounds are commonly used preoperatively, but few institutions use iodine compounds intraoperatively, particularly with repeated application. The selection of antibiotic administration and disinfection technique has to be at the surgeon's discretion. However, intracameral antibiotic and intraoperative iodine compound use are techniques that should be widely recognized.

7.
J Reprod Dev ; 58(4): 432-7, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22498815

RESUMEN

Primordial germ cells (PGCs) are embryonic precursors of germline cells with potential applications in genetic conservation, transgenic animal production and germline stem cell research. These lines of research would benefit from improved germline transmission of transplanted PGCs in chimeric chickens. We therefore evaluated the effects of pretransplant X-irradiation of recipient embryos on the efficacy of germline transmission of donor PGCs in chimeric chickens. Intact chicken eggs were exposed to X-ray doses of 3, 6 and 9 Gy (dose rate = 0.12 Gy/min) after 52 h of incubation. There was no significant difference in hatching rate between the 3-Gy-irradiated group and the nonirradiated control group (40.0 vs. 69.6%), but the hatching rate in the 6-Gy-irradiated group (28.6%) was significantly lower than in the control group (P<0.05). No embryos irradiated with 9 Gy of X-rays survived to hatching. X-irradiation significantly reduced the number of endogenous PGCs in the embryonic gonads at stage 27 in a dose-dependent manner compared with nonirradiated controls. The numbers of endogenous PGCs in the 3-, 6- and 9-Gy-irradiated groups were 21.0, 9.6 and 4.6% of the nonirradiated control numbers, respectively. Sets of 100 donor PGCs were subsequently transferred intravascularly into embryos irradiated with 3 Gy X-rays and nonirradiated control embryos. Genetic cross-test analysis revealed that the germline transmission rate in the 3-Gy-irradiated group was significantly higher than in the control group (27.5 vs. 5.6%; P<0.05). In conclusion, X-irradiation reduced the number of endogenous PGCs and increased the germline transmission of transferred PGCs in chimeric chickens.


Asunto(s)
Embrión de Pollo/efectos de la radiación , Desarrollo Embrionario/efectos de la radiación , Células Germinativas/efectos de la radiación , Células Germinativas/trasplante , Mutación de Línea Germinal/efectos de la radiación , Gónadas/efectos de la radiación , Quimera por Radiación/embriología , Crianza de Animales Domésticos/métodos , Animales , Animales Endogámicos , Embrión de Pollo/citología , Embrión de Pollo/embriología , Embrión de Pollo/crecimiento & desarrollo , Pollos , Relación Dosis-Respuesta en la Radiación , Estudios de Factibilidad , Femenino , Células Germinativas/citología , Gónadas/citología , Gónadas/embriología , Supervivencia de Injerto , Inmunohistoquímica/veterinaria , Masculino , Quimera por Radiación/crecimiento & desarrollo , Efectos de la Radiación , Análisis de Supervivencia , Rayos X
8.
Asia Pac J Ophthalmol (Phila) ; 1(5): 283-6, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-26107599

RESUMEN

PURPOSE: The objective of this study was to identify trends in the use of perioperative antibiotic prophylaxis in cataract surgery in Japan. DESIGN: This was a national survey by mail or interview. METHODS: The use of perioperative antibiotic prophylaxis in cataract surgery was evaluated by conducting a survey in 6 regions within Japan from October 1, 2011, to March 1, 2012. RESULTS: Responses were received from 285 (75%) of the 387 surgeons who were surveyed. The results revealed that 89% (255/285) administered ophthalmic antibiotic ointment. Forty-seven percent (133/285) used antibiotics in forms other than ophthalmic ointments within 6 hours after surgery, 7% (19/285) used eyedrops, 24% (67/285) used antibiotics via an irrigation bottle, 1% (2/285) used intracameral injections, and 24% (69/285) used subconjunctival injections. CONCLUSIONS: Although poor intraocular penetration of ophthalmic ointments has been reported, ophthalmic ointments are widely used. The fact that antibiotics should ideally be administered within 6 hours after surgery is not widely recognized. However, intracameral injection, which achieves much higher antibiotic concentration in the anterior chamber than other methods, is a technique that should be widely acknowledged.

9.
Plant Physiol Biochem ; 49(9): 985-95, 2011 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21571540

RESUMEN

To identify nuclear proteins involved in the brassinosteroid (BR) signaling pathway, a targeted proteomic approach was applied to Arabidopsis thaliana suspension-cultured T87 cells. Cell growth was promoted by 0.1 µM brassinolide (BL) and inhibited by 5 µM brassinazole (Brz). Analysis of BR-regulated proteins in nuclear-enriched fractions was carried out using two-dimensional polyacrylamide gel electrophoresis with a special fluorescent dye. Proteins of interest were identified by correlating normalized spot volume of proteins on the gels with cellular BR level (Brz-treated cells, extremely low level of BRs; control cells, normal level of BRs; BL-treated cells, high level of BRs). A number of BR-responsive proteins were detected and some of these proteins were identified by nano-liquid chromatography-tandem mass spectrometry after enzymatic digestion. Fluctuations in eight identified nuclear proteins in BL-treated cells were investigated in the first 12 h of treatment. Three nuclear BR-responsive proteins, Nucleosome Assembly Protein (NAP) 1;1, Band 7 Family Protein, and Vernalization Independence 3, significantly decreased during this time. Meanwhile, NAP1;2, S-Adenosylmethionine Synthetase 2, and 60S Ribosomal Protein L14 increased markedly over time. Since some of these proteins are reportedly related to chromosome remodeling, cell growth induced by BL may involve chromatin remodeling. Interestingly, NAP1;2 was found to be post-translationally modified in response to cellular BR levels. Our study of quantitative protein changes in the nucleus provides valuable insight into BR-induced cellular and physiological responses.


Asunto(s)
Proteínas de Arabidopsis/biosíntesis , Arabidopsis/metabolismo , Brasinoesteroides/farmacología , Núcleo Celular/metabolismo , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Proteínas Nucleares/biosíntesis , Células Vegetales/metabolismo , Reguladores del Crecimiento de las Plantas/farmacología , Arabidopsis/citología
10.
Reprod Fertil Dev ; 22(8): 1237-46, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-20883649

RESUMEN

The unique accessibility of chicken primordial germ cells (PGCs) during early development provides the opportunity to combine the reproduction of live animals with genetic conservation. Male and female Gifujidori fowl (GJ) PGCs were collected from the blood of early embryos, and cryopreserved in liquid nitrogen for >6 months until transfer. Manipulated GJ embryos were cultured until hatching; fertility tests indicated that they had normal reproductive abilities. Embryos from two lines of White Leghorn (24HS, ST) were used as recipients for chimera production following blood removal. The concentration of PGCs in the early embryonic blood of 24HS was significantly higher than in ST (P < 0.05). Frozen-thawed GJ PGCs were microinjected into the bloodstream of same-sex recipients. Offspring originating from GJ PGCs in ST recipients were obtained with a higher efficiency than those originating from GJ PGCs in 24HS recipients (23.3% v. 3.1%). Additionally, GJ progeny were successfully regenerated by crossing germline chimeras of the ST group. In conclusion, the cryogenic preservation of PGCs from early chicken embryos was combined with the conservation of live animals.


Asunto(s)
Pollos/genética , Criopreservación/veterinaria , Especies en Peligro de Extinción , Células Germinativas/trasplante , Animales , Embrión de Pollo , Quimera , Técnicas de Cultivo de Embriones/veterinaria , Femenino , Fertilidad , Sangre Fetal/citología , Inseminación Artificial/veterinaria , Masculino , Microinyecciones/veterinaria
11.
Ophthalmic Surg Lasers Imaging ; 40(5): 513-5, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19772280

RESUMEN

Variations in the morphology of the aneurysm and its serosanguineous complications serve to make a retinal arteriolar macroaneurysm, a common masquerading entity, particularly if it is accompanied by another un-associated retinal vascular abnormality. The authors present a patient who had an unusually large retinal arteriolar macroaneurysm in conjunction with a congenital retinal macrovessel.


Asunto(s)
Aneurisma/diagnóstico , Arteriolas , Arteria Retiniana/anomalías , Enfermedades de la Retina/congénito , Diagnóstico Diferencial , Femenino , Angiografía con Fluoresceína , Fondo de Ojo , Humanos , Persona de Mediana Edad , Arteria Retiniana/patología , Enfermedades de la Retina/diagnóstico , Índice de Severidad de la Enfermedad
12.
Virchows Arch ; 450(1): 103-8, 2007 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17111127

RESUMEN

We report a case of crystal-storing histiocytosis (CSH) associated with mucosa-associated lymphoid tissue (MALT) lymphoma of the ocular adnexa. The patient was an 81-year-old woman who presented with a 5-month history of a slowly enlarging tumor on her left lower eyelid. The tumor was 2 cm in the largest diameter, involving both inferior oblique and inferior rectus muscles. Histological examination revealed that the tumor was composed predominantly of sheets of spindle-shaped cells resembling striated muscle cells, and scattered aggregates of atypical lymphoid cells at the periphery of the tumor, showing prominent plasmacytoid differentiation. Immunohistochemical and ultrastructural analyses demonstrated that the spindle-shaped cells were CD68-positive histiocytes containing abundant rod-like and/or rectangular crystals in their cytoplasm, consistent with the diagnosis of CSH. The scattered aggregates of atypical lymphoid cells were diagnosed as MALT lymphoma based upon their immunophenotype, featuring diffusely positive staining for CD20, but negative for CD3, CD5, and CD10, and monotypic expression of IgM-kappa in cells with plasmacytoid differentiation. Although CSH is a well-recognized manifestation in lymphoproliferative disorders in the literature, CSH complicated by MALT lymphoma has only very rarely been reported. Given the rarity of this, difficulties in diagnosis may arise especially in cases where histiocytic proliferation overwhelms the underlying lymphoproliferative diseases.


Asunto(s)
Neoplasias de los Párpados/patología , Histiocitosis/patología , Inmunoglobulina M/química , Linfoma de Células B de la Zona Marginal/patología , Anciano , Anciano de 80 o más Años , Cristalización , Neoplasias de los Párpados/complicaciones , Femenino , Histiocitosis/etiología , Histiocitosis/inmunología , Humanos , Linfoma de Células B de la Zona Marginal/complicaciones
13.
Invest Ophthalmol Vis Sci ; 46(10): 3899-905, 2005 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-16186380

RESUMEN

PURPOSE: Strabismus that develops shortly after birth is known to cause temporal-to-nasal eye movement asymmetries under monocular viewing. The neural mechanisms underlying this deficit are not well understood. In the current study, the hypothesis that this eye movement anomaly reflects a similar asymmetry in the directional response properties of neurons in the early stages of cortical processing was examined. METHODS: Strabismus was simulated with optical methods in infant monkeys between 4 and 14 weeks of age. When the monkeys were mature, microelectrode recording experiments were conducted in the primary visual cortex (V1) and visual area 2 (V2). After the spatial frequency of sine wave-grating stimuli for each neuron was optimized, each neuron's responsiveness to 24 directions of stimulus movement was measured. The preferred direction and the strength of directional bias were determined by a vector summation method: RESULTS: There was not an overabundance of neurons in V1 or V2 of strabismic monkeys preferring the temporal-to-nasal direction of stimulus movement. However, the average directional bias was significantly reduced in these strabismic monkeys. Interocular suppression was highly prevalent, and this suppression was stronger and more common in neurons dominated by the ipsilateral eye. CONCLUSIONS: The results suggest that the eye movement asymmetries in strabismic subjects do not result from similar asymmetries in the directional properties of V1 or V2 neurons, but rather reflect impoverished cortical signals to the brain stem nuclei that control eye movements.


Asunto(s)
Percepción de Movimiento/fisiología , Neuronas/fisiología , Estrabismo/fisiopatología , Corteza Visual/fisiopatología , Animales , Animales Recién Nacidos/fisiología , Modelos Animales de Enfermedad , Predominio Ocular/fisiología , Movimientos Oculares/fisiología , Macaca mulatta , Microelectrodos , Visión Binocular/fisiología
14.
J Neurophysiol ; 90(5): 3012-23, 2003 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-14615425

RESUMEN

Experiencing binocularly conflicting signals early in life dramatically alters the binocular responses of cortical neurons. Because visual cortex is highly plastic during a critical period of development, cortical deficits resulting from early abnormal visual experience often mirror the nature of interocular decorrelation of neural signals from the two eyes. In the preceding paper, we demonstrated that monkeys that experienced early alternating monocular defocus (-1.5, -3.0, or -6.0 D) show deficits in stereopsis that generally reflected the magnitude of imposed monocular defocus. Because these results indicated that alternating monocular defocus affected the higher spatial frequency components of visual scenes more severely, we employed microelectrode recording methods to investigate whether V1 neurons in these lens-reared monkeys exhibited spatial-frequency-dependent alterations in their binocular response properties. We found that a neuron's sensitivity to interocular spatial phase disparity was reduced in the treated monkeys and that this reduction was generally more severe for units tuned to higher spatial frequencies. In the majority of the affected units, the disparity-sensitivity loss was associated with interocular differences in monocular receptive field properties. The present results suggest that the behavioral deficits in stereopsis produced by abnormal visual experience reflect at least in part the constraints imposed by alterations at the earliest stages of binocular cortical processing and support the hypothesis that the local disparity processing mechanisms in primates are spatially tuned and can be independently compromised by early abnormal visual experience.


Asunto(s)
Ambliopía/fisiopatología , Neuronas/fisiología , Disparidad Visual/fisiología , Visión Binocular/fisiología , Visión Monocular/fisiología , Animales , Macaca mulatta , Estimulación Luminosa/métodos , Trastornos de la Visión/fisiopatología
15.
Vis Neurosci ; 19(1): 85-96, 2002.
Artículo en Inglés | MEDLINE | ID: mdl-12180862

RESUMEN

Neither discrete peripheral retinal lesions nor the normal optic disk produces obvious holes in one's percept of the world because the visual brain appears to perceptually "fill in" these blind spots. Where in the visual brain or how this filling in occurs is not well understood. A prevailing hypothesis states that topographic map of visual cortex reorganizes after retinal lesions, which "sews up" the hole in the topographic map representing the deprived area of cortex (cortical scotoma) and may lead to perceptual filling in. Since the map reorganization does not typically occur unless retinotopically matched lesions are made in both eyes, we investigated the conditions in which monocular retinal lesions can induce comparable map reorganization. We found that following monocular retinal lesions, deprived neurons in cat area 17 can acquire new receptive fields if the lesion occurred relatively early in life (8 weeks of age) and the lesioned cats experienced a substantial period of recovery (>3 years). Quantitative determination of the monocular and binocular response properties of reactivated units indicated that responses to the lesioned eye for such neurons were remarkably robust, and that the receptive-field properties for the two eyes were generally similar. Moreover, excitatory or inhibitory binocular interactions were found in the majority of experimental units when the two eyes were activated together. These results are consistent with the hypothesis that map reorganization after monocular retinal lesions require experience-dependent plasticity and may be involved in the perceptual filling in of blind spots due to retinal lesions early in life.


Asunto(s)
Lesiones Oculares/fisiopatología , Neuronas/fisiología , Retina/lesiones , Corteza Visual/fisiopatología , Vías Visuales/fisiopatología , Animales , Gatos , Sensibilidad de Contraste/fisiología , Retina/patología , Visión Binocular/fisiología , Percepción Visual/fisiología
16.
Invest Ophthalmol Vis Sci ; 43(4): 1262-9, 2002 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11923274

RESUMEN

PURPOSE: To determine how the duration of early strabismus influences the severity of loss of disparity sensitivity in V1 neurons and the effects of extensive poststrabismus visual experience on the maintenance of functional binocular connections. METHODS: Concomitant strabismus was optically simulated in 10 rhesus monkeys using a prism-rearing procedure. The onset of strabismus was kept constant at 4 weeks of age and the duration was maintained for 2, 4, or 8 weeks. In one group of monkeys (infants), the neurophysiological experiments were conducted immediately after the period of rearing with prisms. In another group (adults), after the termination of the prism-rearing regimen at either 8 or 12 weeks of age, the monkeys were kept in a normal housing environment until maturity and behavioral testing was conducted before the recording experiments to determine the animal's monocular and binocular visual capacities. To assess the effects of the period of early strabismus on binocular interactions in V1, extracellular single-unit recording methods were used in anesthetized and paralyzed monkeys, and dichoptic sine-wave gratings were used as stimuli. RESULTS: In all strabismic monkeys, the sensitivity of V1 units to interocular spatial phase disparity (disparity sensitivity) was significantly reduced, and the prevalence of binocular suppression was higher than that found in age-matched control animals. Although 8 weeks of strabismus resulted in a slightly larger loss of disparity sensitivity, the overall effects of the duration of strabismus were surprisingly small in infant strabismic monkeys. After poststrabismus visual experience, a small but significantly higher degree of disparity sensitivity was noted in V1 if prism-rearing was terminated after 4 weeks of strabismus (i.e., at 8 weeks of age), but not after 8 weeks of strabismus (i.e., at 12 weeks of age). CONCLUSIONS: A brief period (2 weeks) of misalignment after the emergence of stereopsis is sufficient to drastically reduce the functional binocular connections in V1, and longer periods of strabismus result in little additional loss in disparity sensitivity. Clinically, these results suggest that taking corrective measures for infantile esotropes before the known onset age for stereopsis may be important for maintaining better binocular sensory function and better interocular alignment at later stages of development.


Asunto(s)
Neuronas/fisiología , Estrabismo/fisiopatología , Visión Binocular/fisiología , Corteza Visual/fisiopatología , Envejecimiento/fisiología , Animales , Electrofisiología , Análisis de Fourier , Macaca mulatta , Modelos Animales , Factores de Tiempo
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