Eye Refraction in Doubly Exchanged Monozygotic Twins.

This case study examined the hypothesis that longer outdoor time results in normal vision and refractive status, using unique genetically informative kinships. The participants were the members of 29-year-old doubly exchanged monozygotic male twin pairs from Bogotá, Colombia, in South America. Comprehensive ophthalmological examinations, including uncorrected and corrected visual acuity, refraction and keratometry, and visual life history interviews were undertaken; all examinations were conducted by two ophthalmologists blind to the hypothesis, relatedness, and rearing status of the four participants. Normal uncorrected vision and refractive status were present in the two rural-raised, unrelated brothers, relative to their urban-raised counterparts. Uncorrected visual acuities were 20/160 and 20/200 for the city-raised twins and 20/20 and 20/30 for the country-raised twins. Premature birth, low birth weight, computer use, and reading time could not explain these differences. It was concluded that time spent outdoors appears to be a significant factor in the development of myopia, reinforcing extant findings via a novel experimental approach.

Sensory function in severe semilobar holoprosencephaly.

We report a 4-year-old child with severe semi-lobar holoprosencephaly (HPE) not expected to survive after birth. Magnetic resonance imaging (MRI) revealed agenesis of the corpus callosum, absence of the third ventricle, fused thalami and basal ganglia. To investigate sensory function, visual, auditory and somatosensory evoked potential and imaging studies were carried out. The visual response evoked by human face stimuli evoked larger responses over the left side of the holosphere as compared to responses evoked by checkerboard pattern, while auditory evoked potentials were evident over the frontal regions to both pure tones and speech stimuli. No consistent scalp somatosensory evoked potentials were evident. This case demonstrates that electrophysiological measures are able to identify and quantify sensory processing not expected to be present based on the anatomical presentation of the cortex in a child with severe HPE.

Zone I retinopathy of prematurity: clinical characteristics and treatment outcomes.

PURPOSE: To study the clinical characteristics and treatment outcomes after laser and surgical treatment in a series of infants with zone I retinopathy of prematurity (ROP). METHODS: Preterm infants less than 1,500 g at birth diagnosed with zone I ROP were studied. Fifty-seven consecutive eyes in 29 infants with zone I ROP were treated with indirect diode laser. Within zone I, two anatomic subgroups (anterior and posterior) were defined. Additionally, 27 eyes (15 patients) with retinal detachment secondary to zone I ROP were surgically treated. Structural outcomes were evaluated 3 months after surgery. RESULTS: Atypical morphologic characteristics were observed. Thirty-one out of 48 eyes (64.6%) with anterior zone I ROP and none of the 9 eyes with posterior zone I ROP had a favorable outcome (P < 0.001) after photocoagulation. In the surgery group, 14 out of 19 (74%) eyes with stage 4 and 1 out of 8 (13%) eyes with stage 5 had favorable outcomes. CONCLUSIONS: Atypical clinical features can be observed in zone I ROP. A posterior localization of the disease carries a worse prognosis after laser photocoagulation. Surgical intervention can effectively reattach the retina in a significant number of zone I ROP-related retinal detachments.