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Howard D Pomeranz

Publications and source records attributed to Howard D Pomeranz.

14 recordsLinked to original sources
PubMed2006

Neuroprotective effects of brimonidine treatment in a rodent model of ischemic optic neuropathy.

Ischemic optic neuropathy (ION) is a common disorder caused by disruption of the arterial blood supply to the optic nerve. It can result in significant loss of visual acuity and/or visual field. An ischemic optic nerve injury was produced in rats by intravenous injection of Rose Bengal dye followed by argon green laser application to the retinal arteries overlying the optic nerve, causing a coagulopathy within the blood vessels and disruption of optic nerve and retinal perfusion. The effect of brimonidine tartrate eye drops on survival of retinal ganglion cell axons in this experimental paradigm was studied. One eye was treated and the contralateral eye served as a control. Four groups of animals were used for this study. Group 1 received 7 days of treatment with 0.15% brimonidine tartrate eye drops twice a day prior to the ischemic injury. Group 2 animals received 0.15% brimonidine tartrate eye drops twice a day for 14 days after photocoagulation injury. Animal groups 3 and 4 received eye drops of 0.9% NaCl twice a day either daily for 7 days before injury or daily for 14 days, respectively. All rats were sacrificed 5 months after the injury to ascertain long-term optic axon survival. Coagulopathy-induced optic nerve ischemia resulted in a 71% loss of optic axons. Treatment with brimonidine daily for the 7 days prior to the injury resulted in a greater survival of optic axons, with only a 56.1% loss compared to control. Brimonidine treatment every day for 14 days after the ischemic injury did not result in a significant rescue of optic axons compared to injury alone. In summary, the application of brimonidine eye drops for one week prior to an ischemic injury resulted in a statistically significant increase in survival of optic axons within the injured optic nerves. Brimonidine treatment of the eye after the ischemic injury did not result in axon rescue, and axon loss was similar to the injured optic nerves treated with saline only. These results suggest that brimonidine may have potential use for prevention of ION in at-risk patients.

Adrenergic alpha-Agonists↗
PubMed2006

Histological and morphometric evaluation of transient retinal and optic nerve ischemia in rat.

Non-arteritic anterior ischemic optic neuropathy is caused by a transient optic nerve ischemia and results in permanent vision loss. Currently, there is no effective treatment for this ischemic optic nerve injury. This study characterized the duration and extent of ischemia induced after a coagulopathy injury to the optic nerve of adult rats. Acute ischemia was induced in adult rats by intravenous injection of Rose Bengal dye, followed by argon green laser treatment of the vessels at the optic disc. Rats were assessed in the short-term for hypoxyprobe-1 binding and expression of hypoxia inducible factor-1alpha (HIF-1 alpha) and fractin, markers of neuronal injury. Five months after injury, optic axon number was quantified. The coagulopathy injury resulted in short-term hypoxia in the optic nerve and retina. Tissues were hypoxic within 15 min of the coagulopathy injury, but normoxic by 24 h as measured by hypoxyprobe-1 staining. Both HIF-1alpha and fractin were upregulated in ganglion cells variably across the retina. Five months after the ischemic injury, there was a 71% reduction in optic axon number compared to controls. It is critical to have a reproducible and relevant method for producing transient hypoxia in order to test therapeutic strategies for rescuing injured neurons. The coagulopathy induced in this study resulted in a reproducible and transient ischemic optic nerve injury and long-term axonal loss. This ischemia shows similar, although not identical, morphological and physiological changes to those seen in the human eye after optic nerve ischemia. We are currently testing therapeutic strategies to protect ganglion cells from degeneration after this ischemic injury.

Animals↗
PubMed2006

Visual field defects and retinal nerve fiber layer defects in eyes with buried optic nerve drusen.

PURPOSE: To evaluate the visual field with the use of automated perimetry and to evaluate the retinal nerve fiber layer (RNFL) with optical coherence tomography (OCT) in patients with buried optic nerve drusen (OND). DESIGN: Observational case control study. METHODS: Eyes with buried OND were defined as eyes with ultrasound-proved drusen that were not visible with indirect slit-lamp biomicroscopy. All eyes underwent automated perimetry. Some eyes underwent OCT to evaluate the RNFL. RESULTS: Fifty-eight eyes of 41 patients with buried OND were evaluated. Three eyes (5%) had inferior arcuate scotomas. The other 55 eyes did not have visual field defects. Twenty-one of the eyes without visual field defects underwent RNFL analysis with OCT. All 21 eyes had normal average RNFL thickness. Some eyes had focal RNFL defects, but it is not clear whether these defects were clinically significant. CONCLUSION: Visual field defects are uncommon in eyes with buried OND. Eyes with buried OND may have focal RNFL defects but have normal average RNFL thickness. In patients with buried OND and a visual field defect, consideration should be given to searching for other causes of the defect, especially if the defect is substantial.

Adolescent↗
PubMed2006

Achiasmia and unilateral optic nerve hypoplasia in an otherwise healthy infant.

An 18-month-old white boy, observed by his parents at 1-2 months age to have poor visual attentiveness and nystagmus, underwent an ophthalmological evaluation. The patient also underwent unsedated 5-channel flash visual evoked potentials (VEP) and sedated electroretinogram (ERG) testing as well as magnetic resonance imaging (MRI) of the brain and orbits. The VEP in response to monocular stimulation demonstrated occipital asymmetry and was clearly suggestive of crossed asymmetry and also showed right optic nerve hypoplasia. The MRI and fundoscopic examinations supported the findings of achiasmia and probable optic nerve hypoplasia. The patient also had decreased Teller card visual acuity, nystagmus and a variable right esotropia. Neurological examination was normal. The ophthalmological and MRI findings in this 18-month-old male patient support the diagnosis of isolated non-decussating retinal-fugal fibre syndrome as well as hypoplasia of the optic nerve.

Electroretinography↗
PubMed2005

Nonarteritic ischemic optic neuropathy developing soon after use of sildenafil (viagra): a report of seven new cases.

Seven patients, aged between 50 and 69 years, had typical features of nonarteritic anterior ischemic optic neuropathy (NAION) within 36 hours after ingestion of sildenafil citrate (Viagra) for erectile dysfunction. Six patients had vision loss within 24 hours after use of the agent. Final visual acuity in the affected eye ranged from 20/20 to light perception. Both eyes were affected in one individual. All affected individuals had pre-existing hypertension, diabetes, elevated cholesterol, or hyperlipidemia. Seven similar cases have been previously reported. Sildenafil may provoke NAION in individuals with an arteriosclerotic risk profile.

Aged↗
PubMed2004

Intrachiasmal craniopharyngioma: treatment with a cisternal catheter drainage and radiation.

A 54-year-old woman who presented with headaches and bitemporal visual field loss had an MRI that disclosed a cystic lesion within the optic chiasm. Craniotomy yielded an inconclusive biopsy; incisional decompression of the cyst provided only temporary improvement in vision. When vision declined 3 months later, an MRI showed recurrence of the cyst. The patient underwent a second craniotomy with biopsy that revealed an adamantinomatous craniopharyngioma. Because of the dangers of surgical removal, the cyst was left in place and connected by catheter to the prechiasmatic cisternal subarachnoid space. She received 54 Gy of three-dimensional conformal x-irradiation. At the time of her last follow-up examination 28 months postoperatively, the patient had marked improvement in her visual acuity and visual fields; an MRI demonstrated that the cyst remained decompressed. Cisternal catheter drainage represents a novel approach to the treatment of this rare variant of craniopharyngioma.

Biopsy↗
PubMed2004

Visual manifestations of visible and buried optic disc drusen.

BACKGROUND: It has been reported that visible optic disc drusen are associated with decreased visual acuity and loss of peripheral visual field. Patients with buried optic disc drusen have not been as well characterized. METHODS: An observational, retrospective review was made of 92 eyes with funduscopic or ultrasonographic evidence of optic disc drusen. Demographics, presenting symptoms, visual acuity, refractive error, intraocular pressure, presence of an afferent pupillary defect, cup-to-disc ratio, appearance of the optic nerve, and visual field were recorded. RESULTS: Fifty-one (55%) of the eyes were symptomatic; among them, 63% had symptoms of visual acuity loss, and 49% had symptoms of visual field loss. Seventy-nine (86%) of the optic discs appeared abnormal on ophthalmoscopy, but only 42% of these had visible drusen. Forty-five (49%) of the eyes had a visual field defect, and 73% of these were nerve fiber bundle in type. Overall, 73% of optic discs with visible drusen had abnormal visual fields compared with only 36% of optic discs with buried drusen (P < 0.05). CONCLUSIONS: Among 92 eyes with optic disc drusen, only slightly more than 50% produced visual symptoms. Fewer than 50% of drusen were visible ophthalmoscopically. Buried optic disc drusen identified by ultrasound had a significantly lower frequency of associated visual field defects than did visible optic disc drusen.

Adolescent↗
PubMed2002

Roth spots.

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Adult↗
PubMed2002

Sildenafil-associated nonarteritic anterior ischemic optic neuropathy.

PURPOSE: To describe the clinical features of five patients who developed nonarteritic anterior ischemic optic neuropathy (NAION) after ingestion of sildenafil citrate (Viagra; Pfizer Pharmaceuticals, New York, NY). DESIGN: Retrospective observational case series. PARTICIPANTS: Five patients with NAION who reported the use of sildenafil citrate before the onset of ocular symptoms. MAIN OUTCOME MEASURES: The symptoms presented, history, ophthalmic examination, and visual field examination of each patient. RESULTS: Nonarteritic anterior ischemic optic neuropathy developed in one eye within minutes to hours after ingestion of sildenafil. Four of the five patients had no vascular risk factors for ischemic optic neuropathy. The patients all developed unilateral blurry vision, altitudinal visual field defects, and optic disc edema. Each of the patients was noted to have a small cup-to-disc ratio in the unaffected optic nerve. CONCLUSIONS: Sildenafil citrate may be associated with NAION. A small cup-to-disc ratio may be a risk factor for development of NAION in association with the use of sildenafil.

3',5'-Cyclic-GMP Phosphodiesterases↗