A new VEP system for studying binocular single vision in human infants.

Visual evoked potentials (VEPs), that provide unequivocal objective evidence of cortical binocularity have been recorded from adults and young infants using a new VEP system developed for this purpose. The system uses alternating field stereoscopy (AFS) to present separate visual stimuli to each eye. With this system, the binocular image pairs to the right and left eyes alternate at a high rate on a single video monitor. The subject wears spectacles incorporating light-scattering liquid crystal lenses which alternate electronically between opaque and clear modes in synchrony with the video monitor. To detect cortical binocularity, the system analyzes VEP activity mathematically and identifies significant responses at test frequencies reflecting binocular cortical interactions exclusively. Three types of binocular stimuli were presented: (1) dynamic random dot correlograms (correlograms); (2) dynamic random dot stereograms (stereograms); and (3) dichoptic checkerboard stimuli. The correlograms are generated when moving random dot patterns presented to each eye alternate between two phases, correlated and anticorrelated. With the stereograms, portions of random dot patterns presented to each eye are shifted horizontally relative to each other at a fixed rate, alternately producing crossed and uncrossed binocular disparities. Subjectively, these patterns appear to shift in depth. Dichoptic checkerboard stimuli are regular checkerboard patterns which reverse at different rates (frequencies) for each eye. Binocular VEPs are generated due to cortical interactions at the difference (beat) frequency. Using this VEP system, we have recorded binocular VEPs from 10 normal adults and more than 40 infant subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

A cohort study of transcutaneous oxygen tension and the incidence and severity of retinopathy of prematurity.

BACKGROUND: Retinopathy of prematurity is a disease affecting the blood vessels of the retina in premature infants that may result in scarring, retinal detachment, and loss of vision. An association between this condition and the exposure of premature infants to supplemental oxygen has been postulated, but the relation between retinopathy of prematurity and blood oxygen levels has not been defined. The purpose of this study of a cohort of preterm infants was to correlate the incidence and severity of retinopathy of prematurity with the duration of exposure to different ranges of oxygen tension as measured by transcutaneous monitoring (tcPO2). METHODS: One hundred one premature infants (birth weight, 500 to 1300 g) requiring supplemental oxygen had continuous monitoring of tcPO2. The number of hours during which the tcPO2 was 80 mm Hg or higher was tabulated for each infant during the first four weeks of life. RESULTS: There was a significant association between the amount of time that the tcPO2 was greater than or equal to 80 mm Hg and the incidence and severity of retinopathy of prematurity. The odds ratio for each 12-hour period in which the tcPO2 was greater than or equal to 80 mm Hg was 1.9 (95 percent confidence interval, 1.2 to 3.0) after adjustment for the following factors: birth weight less than or equal to 1300 g (odds ratio, 2.3 [95 percent confidence interval, 1.6 to 3.4]), five-minute Apgar score of 7 or less (odds ratio, 7.2 [95 percent confidence interval, 2.5 to 21]), and exposure to inspired oxygen at a concentration greater than or equal to 0.4 (odds ratio, 1.0 [95 percent confidence interval, 0.97 to 1.05]). The association was stronger for tcPO2 values of greater than or equal to 80 mm Hg occurring from the second through the fourth week of life; during this period, the adjusted odds ratio for a 12-hour period of such exposure was 3.1 (95 percent confidence interval, 1.6 to 6.1). CONCLUSIONS: This study supports an association between the incidence and severity of retinopathy of prematurity and the duration of exposure to arterial oxygen levels of 80 mm Hg or higher, measured transcutaneously.

Complete ptosis as a result of removal of epibulbar lipodermoid.

Partial ptosis following epibulbar epidermoid removal is a known complication. The mechanism is generally thought to be symblepharon following aggressive dissection, injury to the levator aponeurosis, or injury to the branch of the ocular motor nerve to the levator muscle. We now report a case of complete ptosis thought to be neurogenic in origin. The possible mechanism is discussed.

Molecular genetics of human blue cone monochromacy.

Blue cone monochromacy is a rare X-linked disorder of color vision characterized by the absence of both red and green cone sensitivities. In 12 of 12 families carrying this trait, alterations are observed in the red and green visual pigment gene cluster. The alterations fall into two classes. One class arose from the wild type by a two-step pathway consisting of unequal homologous recombination and point mutation. The second class arose by nonhomologous deletion of genomic DNA adjacent to the red and green pigment gene cluster. These deletions define a 579-base pair region that is located 4 kilobases upstream of the red pigment gene and 43 kilobases upstream of the nearest green pigment gene; this 579-base pair region is essential for the activity of both pigment genes.

A hemorrhagic form of Zone I retinopathy of prematurity.

A premature infant who had vascularized only Zone I developed bilateral progressive hemorrhaging in the posterior poles. Subsequently, vitreous hemorrhages and retinal detachments occurred without any progression through Stages I, II, or III of retinopathy of prematurity. This clinical presentation has not been reported previously. These findings suggest profound underlying abnormalities of funduscopically normal Zone I retinal vasculature. Pathologic findings were consistent with end-stage retinopathy of prematurity.

Visual paraneoplastic syndrome associated with undifferentiated endometrial carcinoma.

We report a case of visual paraneoplastic syndrome associated with undifferentiated endometrial carcinoma. This syndrome has not previously been reported with this type of tumour; it has occurred most often with small-cell carcinoma of the lung. Electroretinography and histopathological examination have consistently shown the site of injury to be the outer retina. We review the findings in the reported cases and the proposed causes of the loss of vision in this condition.

Retinopathy of prematurity. Diagnosis, severity, and natural history.

This article presents data gathered in a prospective clinical trial of constant monitoring of oxygen therapy on the diagnosis, severity (as coded by a severity index [SI]) and natural history of retinopathy of prematurity (ROP) in 214 surviving infants with birthweights less than or equal to 1300 g. ROP developed in 119 (55.6%) infants and, of these, cicatricial ROP developed in nine (7.6%). The disease was diagnosed at 8-9 weeks on the average in infants with birthweights less than 900 g and 4-5 weeks in infants 900 to 1300 g. Those infants in whom the disease regressed, ROP lasted approximately 15 weeks. The severity of the disease, as defined by the SI, was strongly correlated with the birthweight of the infant and weakly correlated with the total duration of oxygen therapy.

Fatal metabolic acidosis, hyperglycemia, and coma after steroid therapy for Kearns-Sayre syndrome.

Two adolescent boys with Kearns-Sayre syndrome (progressive external ophthalmoplegia, heart block, elevated CSF protein, and ragged-red muscle fibers) developed lethargy, increasing somnolence, polydipsia, polyphagia, and polyuria after a brief course of steroid therapy. Both had hyperglycemia and acidosis. Nonketotic, lactic acidosis was present in one and ketosis in the other. Severe respiratory failure developed, and both patients died. Postmortem revealed fatty infiltration of the pancreas in addition to a diffuse spongiform encephalopathy.

Hyperglycemic acidotic coma and death in Kearns-Sayre syndrome.

This paper presents the clinical and metabolic findings in two young boys with long-standing Kearns-Sayre syndrome. Following short exposure to oral prednisone, both boys developed lethargy, increasing somnolence, polydipsia, polyphagia, and polyuria. Both presented in the emergency room with profound coma, hypotension, severe hyperglycemia, and acidosis. Nonketotic lactic acidosis was present in one and ketosis without a known serum lactate level was present in the other. Respiratory failure rapidly ensued and both patients expired in spite of efforts at resuscitation. We believe these two cases represent a newly described and catastrophic metabolic-endocrine failure in the Kearns-Sayre syndrome.

Spontaneous corneal perforation and extrusion of intraocular contents in premature infants.

Unilateral spontaneous corneal perforation with expulsion of intraocular contents is reported in two very small, high risk premature neonates. The one surviving infant demonstrated unilateral microphthalmos with aphakia and a small leukoma. The cause of this phenomenon is not clear, and measures which might be taken to prevent its occurrence are not obvious.

Telangiectatic osteosarcoma: unusual behaviour.

The telangiectatic variant of osteogenic sarcoma is rare. Its biologic behaviour, treatment and prognosis are controversial. The case of a 15-year-old girl with this tumour is described. Both the location and clinical behaviour of the tumour were unusual. The tumour, which involved the distal ulna, was initially treated by a limited resection of the distal 8 cm of ulna. Sixty-nine months later the tumour recurred locally; there was no evidence of metastases. The forearm was amputated and the patient was then treated aggressively by chemotherapy. She was well 42 months later. This case illustrates the tendency for telangiectatic osteosarcoma to recur locally if it is not radically excised.

Direct trauma to the superior oblique tendon following penetrating injuries of the upper eyelid.

We report two cases of direct trauma to the superior oblique tendon after penetrating injury of the upper eyelid with hook-shaped tools. Both patients originally presented with a Knapp type VII superior oblique palsy, but one patient severed the superior oblique tendon proximal to the trochlea, whereas the other patient engaged the distal reflected segment of the tendon with the hook and pulled it forward into the upper eyelid.

Cogan's syndrome: a treatable cause of neurosensory deafness.

Cogan's syndrome, nonsyphilitic interstitial keratitis associated with vestibuloauditory deficits, can vary in its presentation. This paper describes an unusual case in which deafness developed while the patient was receiving topical therapy with prednisolone and homatropine for mild bilateral iritis and right-sided nodular episcleritis. The 10-year-old boy's hearing improved dramatically with high-dose systemic steroid therapy. The importance of being aware that deafness may occur in children undergoing treatment for "routine" iritis is emphasized.