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At least 19 recordsLinked to original sources
PubMed1975

Suppressive processes in binocular vision: ocular dominance and amblyopia.

Recent suggestsions linking suppression observed in amblyopia ex anopsia with that manifested in normal ocular dominance coordinations were experimentally tested. Training procedures which normally alleviate functional amblyopic suppression were shown to have similar results in alleviating the suppression of the nondominant eye in visually normal observers. Methodological and theoretical implications of these results are discussed.

Adult↗
PubMed1987

Latent/manifest latent nystagmus reversal using an ocular prosthesis. Implications for vision and ocular dominance.

Latent/manifest latent nystagmus (LMLN) is a jerk nystagmus with a decreasing-velocity or linear slow phase whose fast phase is in the direction of the fixating eye. Change of the fixating eye by alternating tropias or cover will cause reversal of the LMLN to preserve this relationship. In the dark, where no fixation is possible, the fast phases of LMLN are in the direction of the intended fixating eye; actual visual input will override this effect of intention. A patient with persistent hyperplastic primary vitreous of the right eye, which was enucleated at age 9 due to glaucoma, had LMLN with fast phases to the left. His congenitally blind right eye was replaced with an ocular prosthesis whose movements were conjugate with his seeing eye. In the dark, we found that his LMLN spontaneously reversed as the normally fixating left eye became esotropic. Furthermore, as is the case with LMLN patients who have sight in both eyes, he was able to willfully reverse his LMLN in the dark by alternating his "fixating" eye. We conclude from these observations that the direction of LMLN is determined at a cortical level, is intimately related to the intended fixating eye and that eye "dominance" is predetermined and not altered by visual abnormalities, including blindness.

Adolescent↗
PubMed1993

Ocular and vision defects in preschool children.

Ocular and/or vision defects are one of the commonest reasons for the referral of young children to hospital. In a survey of a birth cohort in one health district, 7.1% of children were diagnosed as having such defects by their fifth birthday; 2.1% were detected before the age of 2 years, and 5.1% between 2 and 5 years. Up to the age of 2 years, low birthweight children and those who require postnatal special care had a higher risk of having an ocular or vision defect diagnosed and were more likely to have serious visual impairment than other children. In contrast, between the ages of 2 and 5 years of age these high risk children showed no continuing increased risk of having a defect diagnosed, nor did they show any differences in the severity or type of vision defects compared with other children. Averaged over the years studied, the incidence of defects presenting to specialist eye clinics among all 2-5 year olds was 1.7%, higher than the 1.1% found for 0-2 year olds. This increase consisted primarily of children with refractive errors only.

Child, Preschool↗
PubMedDate not supplied

Visual acuity, binocular vision, and ocular muscle balance in VLBW children.

Thirty-four very low birth weight (VLBW) 6-year olds and 31 normal birth weight (NBW) 6-year olds were assessed for visual acuity, binocular vision, and ocular muscle balance. Significantly more of the children in the VLBW group failed the tests of binocular vision and ocular muscle balance. Failure in tests of binocular vision was associated with higher numbers of days on mechanical ventilation and higher number of days in the intensive care nursery during the first months of life.

Child↗
PubMedDate not supplied

Review of experience with retinopathy of prematurity from the Pavia registry (1990-1993).

In this retrospective study we analysed the prevalence of retino-pathy of prematurity (ROP) and its sequelae in a sample of premature infants with birth weight less than 1500 grams. From 1 January 1990 to 31 October 1993, we studied 160 surviving premature infants with very low birth weight (< 1.500 g) referred to the Neonatal Intensive Care Unit of the I.R.C.C.S. Policlinico San Matteo, Pavia, Italy. Thirty percent of these infants suffered from ROP, and 13.7%, with severe ROP, underwent cryotherapy. These latter had very-very low birth weight (< 1.000 g) and low gestational age (< 28 weeks). Follow-up of 69 infants at 12 months for retinal sequelae, refraction defects, bin-ocular vision and ocular motility impairments gave the following results: 1) strabismus 20.3%; 2) > 3D hyperopia 3%; 3) myopia 30.4%; 4) > 5D myopia 3.7%. The incidence of refraction and ocular motility anomalies in patients with acute ROP with spontaneous remission was similar to that of unaffected premature infants. Conversely, in the patients treated with cryotherapy the incidence of strabismus and > 5D myopia was greater than for untreated infants: 30% vs 15.4% (n.s.) and 14.7% vs 0% (p = 0.05), respectively. Cryotherapy was successful in 91.9% of cases and in 37.8% of cases the cicatricial sequelae were limited to peripheral chorioretinal scars.

Cryotherapy↗
PubMedDate not supplied

[Terson's syndrome. Its surgical resolution].

The observation of 50-year-old patient is presented. Following a traffic crash, he had suffered a left cranial fracture, right subdural hematoma, cranial base fracture and vitreous hemorrhages at the both eyes. Right ocular vision was 1/500, left ocular vision was 1/200. The vitrectomy through pars plana with Tollentino lens at the right eye, without scleral indentation, is made. The postoperative evolution was good, 21 days after the intervention the visual acuity of the right eye reaching 16/20. The role of vitrectomy in vitreous hemorrhages of Terson syndrome is emphasized.

Accidents, Traffic↗
PubMed2006

Effect of refractive surgery on binocular vision and ocular alignment in patients with manifest or intermittent strabismus.

OBJECTIVE: To evaluate the effect of refractive surgery on binocular vision and ocular alignment in patients with manifest or intermittent strabismus, with or without vertical component. SETTING: University Hospital Antwerp, Edegem, Belgium. PATIENTS AND METHODS: 13 patients (22 eyes) with strabismus underwent refractive surgery. Five of these patients presented with an esotropia and four of them with a small vertical deviation. Five patients had a manifest exotropia, of whom two presented with a small vertical deviation. Two patients had an intermittent exotropia with binocular vision, of whom one patient had a vertical deviation. One patient had a hypertropia with a dissociated vertical deviation. RESULTS: Ocular alignment and binocular function remained unchanged postoperatively in all except two patients with high anisometropia who experienced an improvement in binocular function. In these patients, the preoperative manifest deviation became intermittent or latent after surgery, allowing fusion and stereopsis. Vertical deviation was found preoperatively in 8 of the 13 patients. This vertical deviation remained unchanged postoperatively, but improved in one patient with anisometropia. CONCLUSION: Preoperative intermittent or manifest strabismus is not a contraindication for refractive surgery provided some specific recommendations are taken into account, such as an adequate preoperative orthoptic examination and aiming at emmetropia for both eyes.

Adult↗
PubMed2002

Photic resetting of the human circadian pacemaker in the absence of conscious vision.

Ocular light exposure patterns are the primary stimuli for entraining the human circadian system to the local 24-h day. Many totally blind persons cannot use these stimuli and, therefore, have circadian rhythms that are not entrained. However, a few otherwise totally blind persons retain the ability to suppress plasma melatonin concentrations after ocular light exposure, probably using a neural pathway that includes the site of the human circadian pacemaker, suggesting that light information is reaching this site. To test definitively whether ocular light exposure could affect the circadian pacemaker of some blind persons and whether melatonin suppression in response to bright light correlates with light-induced phase shifts of thecircadian system, the authorsperformed experiments with 5 totally blind volunteers using a protocol known to induce phase shifts of the circadian pacemaker in sighted individuals. In the 2 blind individuals who maintained light-induced melatonin suppression, the circadian system was shifted by appropriately timed bright-light stimuli. These data demonstrate that light can affect the circadian pacemaker of some totally blind individuals--either by altering the phase of the circadian pacemaker or by affecting its amplitude. They are consistent with data from animal studies demonstrating that there are different neural pathways and retinal cells that relay photic information to the brain: one for conscious light perception and the other for non-image-forming functions.

Adult↗
PubMed1999

Causes and prevalence of non-vision impairing ocular conditions among a rural adult population in sw Uganda.

Information is scanty about the extent of ocular morbidity in developing countries, particularly for non-vision impairing conditions (NVIC), although these constitute the majority of consultations in eye clinics. We have conducted a survey to determine the prevalence and causes of NVIC in a Ugandan adult population and compared our findings with the work pattern of the district hospital. Adults were screened using Snellen's illiterate E chart and those found with visual impairment (acuity less than 6/18) in either eye were referred to a low-vision clinic, and those with obvious ocular disease or symptoms, but without visual impairment, to an outreach clinic. A total of 2886 (53%) out of 5479 adults were screened. Of these, 257 (8.9%) were referred to the outreach clinic, of whom 173 (67%) attended. Of those attending the low-vision clinic 83% had visual impairment confirmed, and 92% of those attending the outreach clinic were confirmed not to have visual impairment. The four commonest NVIC observed at the outreach clinic were: presbyopia (48%), allergic conjunctivitis (20%), early cataract (9%) and infective conjunctivitis (8%), the same conditions as those most commonly seen at the district hospital. In this community, over 80% of NVIC are caused by four conditions which are potentially either correctable, operable or treatable. Training health workers to recognise and treat these conditions would serve the great majority of eye patients. Hospital activity data can be used cautiously to assess the relative frequency of NVIC in the community.

Adolescent↗
PubMed1996

Prevalence of vision and ocular disease conditions in a clinical pediatric population.

BACKGROUND: The purpose of this study was to fill a significant void in the ophthalmic literature by performing a large scale, comprehensive, prospective study of the prevalence of vision disorders and ocular pathology in a clinical pediatric population using well-defined diagnostic criteria. METHODS: A prospective study was performed on 2,023 consecutive patients between the ages of 6 months and 18 years presenting for an initial comprehensive examination at the Eye Institute of The Pennsylvania College of Optometry. There were 373 subjects between 6 months and 5 years, 11 months of age, and 1,650 subjects between 6 years and 18 years of age. RESULTS: The most important finding from this study is that other than refractive anomalies, the most common conditions optometrists are likely to encounter in a pediatric population are binocular vision and accommodative disorders. The prevalence of accommodative and binocular (strabismic and non-strabismic) vision disorders is 9.7 times greater than the prevalence of ocular disease in children 6 months to 5 years of age, and 8.5 times greater than the prevalence of ocular disease in children 6 to 18 years of age. CONCLUSIONS: The data from this study has great significance for clinicians, optometric educational institutions, health care planners, and administrators. This data suggests that other than refractive anomalies, the most prevalent conditions in the clinical pediatric population are binocular and accommodative disorders. Clinicians should use a minimum data base that includes assessments of accommodation and binocular vision that will allow them to detect conditions with the highest prevalence.

Adolescent↗