Cortical binocularity and monocular optokinetic asymmetry in early-onset esotropia.

PURPOSE: To investigate the correlation between directional asymmetry in ocular responses to monocularly viewed optokinetic stimuli (monocular optokinetic nystagmus, MOKN) and sensory fusion in infants and toddlers with early-onset esotropia. METHODS: Subjects were 14 infants and toddlers with early-onset esotropia (7-26 months old; median, 10 months), and 16 with no esotropia (6-22 months; median, 11 months) who provided control data. Monocular optokinetic nystagmus in response to a 30 degrees/sec square-wave grating (0.25 cycles/degree) was measured by electro-oculogram. Sensory fusion was assessed with visual evoked potentials (VEPs) to random-dot correlograms after correction of the strabismus angle with Fresnel prisms. RESULTS: All subjects with early-onset esotropia had MOKN with a faster slow-phase component for temporal-to-nasalward (TN) than nasal-to-temporalward (NT) motion. Ninety-three percent of subjects had MOKN asymmetry higher than the 95th percentile of the control group. Of subjects who cooperated with VEP fusion testing, 5 subjects with early-onset esotropia (45%) and 11 control subjects (92%) showed evidence of sensory fusion. CONCLUSIONS: Symmetrical MOKN did not develop in infants and toddlers with early-onset esotropia. This deficit existed in most infants who showed sensory- cortical fusion. These results are consistent with the belief that optokinetic nystagmus asymmetry may not be associated with a deficit in the cortical fusion facility, but rather with deficits in binocular pathways projecting to MOKN control centers. These deficits may be associated with abnormal processing subsequent to sensory fusion or with abnormal processing in motion pathways, which run parallel to sensory fusion pathways.

Mortality of hospitalized patients with Candida endophthalmitis.

BACKGROUND: Candida is becoming an important nosocomial pathogen as the incidence of hospital-acquired candidemia is rising. Candida endophthalmitis is a good indicator of systemic candidiasis in hospitalized patients. METHODS: Thirteen (17%) of 76 ophthalmologic consultations for Candida endophthalmitis in our institution had positive findings during a 12-month period. We studied these 13 patients with Candida endophthalmitis to evaluate their outcomes. RESULTS: All 13 patients were admitted to a large tertiary care hospital, and 10 (77%) were in an intensive care unit. The overall mortality was 77% for all patients and 80% for the intensive care patients. This mortality was higher than the overall mortality for all patients in the surgical intensive care unit in our institution (17%), as well as the mortality for our patients with candidemia in the surgical intensive care unit (61%). CONCLUSIONS: The strikingly high mortality in our group of patients with Candida endophthalmitis reflects the fact that they are a seriously ill group with multiple risk factors for Candida infection. This information suggests that the presence of Candida endophthalmitis is a good indicator of high mortality in seriously ill patients in intensive care units.

Characterization of the ocular phenotype of Duchenne and Becker muscular dystrophy.

PURPOSE: Dystrophin, the Duchenne muscular dystrophy gene product, has been localized to the outer plexiform layer of normal human retina. The purpose of this study is to define completely the ocular phenotype associated with mutations at Xp21, the Duchenne muscular dystrophy gene locus. METHODS: Twenty-one patients with a diagnosis of Duchenne muscular dystrophy and five patients with Becker muscular dystrophy had ophthalmologic examinations, including electroretinograms (ERGs). Electroretinogram results were correlated with respect to patient DNA analysis. RESULTS: Twenty-three (88%) patients had reduced scotopic b-wave amplitudes to bright-white flash stimulus, including nine with negative-shaped ERGs. Rod-isolated responses were reduced or not recordable above noise in 14 (67%) patients. Most isolated cone responses (92%) were normal. Flicker amplitudes were reduced in seven patients. Two of these patients with proximal (5' end) deletions had normal scotopic b-waves to dim blue and bright-white flash stimulus. Patients with deletions toward the middle of the gene had greater reductions in their scotopic b-wave amplitudes than patients with deletions located toward the 5' end. Most patients had normal color vision, extraocular muscle function, and Snellen visual acuity. Increased macular pigmentation was seen in 16 patients with Duchenne muscular dystrophy. CONCLUSION: Most patients with Duchenne or Becker muscular dystrophy have evidence of abnormal scotopic ERGs. Patients with deletions in the central region of the gene had the most severe ERG changes. This study supports previous suggestions that dystrophin may play a role in retinal neurotransmission. The presence of increased macular pigmentation and normal photopic ERGs distinguishes patients with Duchenne muscular dystrophy mutations from other X-linked retinal disorders with negative-shaped ERGs.

Dystrophin expression in the human retina is required for normal function as defined by electroretinography.

We have studied retinal function by electroretinography in five Becker and six Duchenne muscular dystrophy patients. All had abnormal electroretinograms with a markedly reduced amplitude for the b-wave in the dark-adapted state. Using three antisera raised to different domains of dystrophin, we identified dystrophin in the outer plexiform layer of human retina. The retinal dystrophin is present in multiple isoforms as the result of alternative splicing. The localization of dystrophin to the outer plexiform layer coincident with the abnormal b-wave suggests that dystrophin is required for normal retinal electrophysiology.