Delayed response of the retina after hyperbaric oxygen exposure.

PURPOSE: To examine retinal electrophysiological function and retinal thickness in healthy eyes before and after hyperbaric oxygen (HBO) exposure. METHODS: The healthy eye in each of six subjects who underwent experimental HBO treatment for branch retinal vein occlusion in the fellow eye was examined using multifocal electroretinography (mfERG) and optical coherence tomography (OCT) at baseline and following a course of five consecutive daily sessions of exposure to HBO at 2.4 atmospheres of absolute pressure lasting 90 min each. RESULTS: After HBO, P1 implicit times of the mfERG were significantly shorter than at baseline. The response was delayed, being undetectable on the day treatment concluded, whereas a 2.65% reduction in implicit time was seen 1 week later (p = 0.032). The P1 implicit time remained 2.49% shorter than at baseline 1 month after the end of the HBO sessions (p = 0.020). The bulk of the response to HBO was found in the foveal and parafoveal regions. No detectable change was seen in mfERG amplitudes or in the volume or thickness of the retina. CONCLUSION: A mfERG component related to bipolar and Müller cell function was accelerated by a short intermittent exposure to HBO. The response developed after the end of the HBO exposure and lasted for at least 3 weeks, suggesting that it was prompted by the withdrawal of HBO rather than the onset and subsequent brief exposure to HBO.

Coumarin embryopathy in an extremely low birth weight infant associated with neonatal hepatitis and ocular malformations.

Coumarin embryopathy (CE) is a well-documented sequelae of prenatal exposure to vitamin K antagonists. We report on a female premature infant (25 weeks' gestation) born to a mother who had received phenprocoumon during pregnancy following mechanical heart valve replacement. The infant presented with impaired coagulation, intraventricular and minor parenchymal cerebral haemorrhages and midface hypoplasia typical of CE. In addition, there was hepatopathy with conjugated hyperbilirubinemia, elevated liver enzymes and repeated episodes of hypoglycemia upon attempts to discontinue glucose supplementation, all lasting for 4 months. There was corneal opacity with anterior segment dygenesis in the left eye, and persistent pupillary membrane, cataract and persistent hyperplastic primary vitreous in the right eye. While liver disease is an uncommon but serious side effect of vitamin K antagonists, this is the first report describing neonatal hepatopathy as part of CE. In anticoagulation of pregnant women with mechanical heart valves, vitamin K antagonists should be used with utmost restraint.