Juvenile pilocytic astrocytomas do not undergo spontaneous malignant transformation: grounds for designation as hamartomas.

AIM: To determine whether juvenile pilocytic astrocytomas WHO grade I have the potential for spontaneous malignant transformation. METHODS: A literature search was performed, cross-referencing juvenile pilocytic astrocytoma, pilocytic astrocytoma, astrocytoma grade I, optic glioma, glioma, low-grade gliomas, polar spongioblastoma, gliocytoma embryonale, and malignant transformation, anaplasia or anaplastic change. Bibliographic PubMed and Google searches were performed, and reference ophthalmology and neuropathology textbooks were utilised. RESULTS: A total of 52 purported cases of malignant transformation were found. Twenty-two of these tumours, however, did not initially match criteria for juvenile pilocytic astrocytoma WHO grade I and were excluded. Six other cases were located within the irradiated field but represented anaplasias developing independently of the primary tumour. The remaining 24 malignancies had all been previously irradiated. CONCLUSION: Juvenile pilocytic astrocytomas WHO grade I do not undergo spontaneous anaplastic transformation. Malignant transformations have only been demonstrated following radiation therapy. Earlier clinical and histopathological opinions regarding juvenile pilocytic astrocytomas as hamartomatous lesions are reaffirmed.

Central corneal thickness and correlation to optic disc size: a potential link for susceptibility to glaucoma.

AIMS: To evaluate a possible relationship between central corneal thickness (CCT) and optic disc area in patients with primary open-angle glaucoma (POAG). METHODS: Patients with POAG underwent eye examination, optic disc imaging with the Heidelberg Retina Tomograph II (HRT II) and ultrasound corneal pachymetry. Exclusion criteria were prior ocular surgery and low-quality HRT II images (HRT standard deviation (SD) >50). Pearson's correlation coefficients were calculated to assess the associations between CCT and optic disc area. RESULTS: 212 eyes of 137 patients with POAG were examined. In all, 66 (48%) subjects were women, 104 (76%) were Caucasian, 26 (19%) African-American and 7 (5%) other races. 72 eyes remained after excluding those with prior intraocular surgery and low-quality HRT II images. In a univariate analysis of this group, CCT was inversely correlated with optic disc surface area (Pearson's correlation coefficient r = -0.284, p = 0.036, n = 72). Mean (SD) disc area was 2 (0.53) mm(2) (n = 160). Caucasians had significantly smaller discs (p<0.001) than other races (Caucasian 1.9 (0.47) mm(2) (n = 119), African-Americans 2.4 (0.54) mm(2) (n = 31), other races 2.3 (0.45) mm(2) (n = 10)). CONCLUSION: CCT is inversely correlated to optic disc area. Although thicker corneas have been recognised to cause slight overestimation of true intraocular pressure (IOP), they may also indicate the presence of a substantially smaller, and thus more robust, optic nerve head. People with thinner corneas which slightly underestimate the true IOP may also have larger and more deformable optic discs.

Photographic reproduction of out-of-focus and distorted ocular imagery.

The necessary settings and parameters were determined for ordinary camera and lens systems to faithfully reproduce out-of-focus and distorted imagery as it falls upon the retina of the human eye. Theoretic considerations of both geometric and physical optics were used to calculate the "relative blur" and distortion produced by refractive error added to ordinary camera lenses as opposed to refractive error in an arbitrary thick-lens optical system bounded by air and fluid (i.e. the eye). In both the camera and the eye, "relative blur" was determined to be directly proportional to dioptric defocus and to aperture size, and effectively independent of the focal length. Distortion of imagery was also found to be independent of the focal length. Photographs corroborate the theoretic findings. A given amount of relative blur, however, appeared somewhat greater when recorded on photographic film than when appreciated by the human eye. The Stiles-Crawford effect, the chromatic aberration of the eye, and neural processing probably each contribute to this difference. Previous investigators have grossly exaggerated blur and distortion in photographs intended to simulate ocular imagery and have drawn misleading conclusions from their results.

Spontaneous regression of optic gliomas: thirteen cases documented by serial neuroimaging.

OBJECTIVE: To demonstrate spontaneous regression of large, clinically symptomatic optic pathway gliomas in patients with and without neurofibromatosis type 1 (NF-1). METHODS: Patient cases were collected through surveys at 2 consecutive annual meetings of the North American Neuro-Ophthalmology Society (NANOS) and through requests on the NANOSNET Internet listserv. Serial documentation of tumor signal and size, using magnetic resonance imaging in 11 patients and computed tomography in 2 patients, was used to evaluate clinically symptomatic optic pathway gliomas. All tumors met radiologic criteria for the diagnosis of glioma and 4 patients had biopsy confirmation of their tumors. In 3 patients, some attempt at therapy had been made many years before regression occurred. In one of these, radiation treatment had been given 19 years before tumor regression, while in another, chemotherapy had been administered 5 years before signal changes in the tumor. In the third patient, minimal surgical debulking was performed 1 year before the tumor began to shrink. RESULTS: Spontaneous tumor shrinkage was noted in 12 patients. Eight patients did not have NF-1. In an additional patient without NF-1, a signal change within the tumor without associated shrinkage was detected. Tumor regression was associated with improvement in visual function in 10 of 13 patients, stability of function in 1, and deterioration in 2. CONCLUSIONS: Large, clinically symptomatic optic gliomas may undergo spontaneous regression. Regression was seen in patients with and without NF-1. Regression may manifest either as an overall shrinkage in tumor size, or as a signal change on magnetic resonance imaging. A variable degree of improvement in visual function may accompany regression. The possibility of spontaneous regression of an optic glioma should be considered in the planning of treatment of patients with these tumors.

Redefining papillorenal syndrome: an underdiagnosed cause of ocular and renal morbidity.

PURPOSE: To report ocular and renal findings specific to the inheritable entity called papillorenal (also known as renal-coloboma) syndrome and relate these to a common cause. DESIGN: Observational case series and genetic study. PARTICIPANTS: Two unrelated probands presenting with absent central retinal vessels and 11 available family members. TESTING: Doppler ultrasonographic imaging of the optic nerves and kidneys, fluorescein angiography, and genetic testing for PAX2 mutations were performed. In selected cases, indocyanine green angiography, scanning laser ophthalmoscope perimetry, Retinal Thickness Analyzer measurements, visual evoked potentials, and magnetic resonance imaging were also performed. MAIN OUTCOME MEASURES: Better defined characteristics of the papillorenal syndrome. RESULTS: Numerous cilioretinal vessels were present with rudimentary or absent central retinal vessels. Superonasal visual field defects, typical for papillorenal syndrome, corresponded to inferotemporal areas of anomalous retinal and choroidal perfusion and hypoplastic retina. Renal hypoplasia was discovered in two affected members of one family (with previously unsuspected renal failure in one case), and recurrent pyelonephritis was discovered in four affected members of the other family. No PAX2 mutations were detected. CONCLUSIONS: In the papillorenal syndrome, the hereditary absence of central retinal vessels may be missed, leading to confusion with isolated coloboma, low-tension glaucoma, and morning glory anomaly. Greater awareness of this syndrome will avoid unneeded glaucoma therapy, allow earlier recognition of renal diseases, and allow genetic counseling. We propose that the papillorenal syndrome is a primary dysgenesis that causes vascular abnormalities predominantly affecting the eye, kidney, and urinary tract, leading to hypoplasia of these structures. The absence of defects in the PAX2 gene in these families suggests that mutations in other genes may also be responsible for this syndrome.

[Spontaneous regression of familial glioma of the optic nerve in a boy with suspected neurofibromatosis 1 (Recklinghausen's disease)]. / Spontannaia regressiia semeinoi gliomy zritel'nogo nerva u mal'chika s predpolagaemym neirofibromatozom I tipa (bolezn' Reklingauzena). .

A boy with a large intracranial glioma of the optic tract and probable neurofibromatosis of the first type was observed for 8 years since the age of 7 years. A series of MR scans was made over this period. A notable decrease of the tumor size was seen on its signals on the MR scans. This was paralleled by an improvement of the vision acuity, color field, and visual field on the involved eye. Patient's grandmother had an intracranial glioma of the optic nerve with a slight but stable decrease of the visual functions. The tumor shape in the grandmother and grandchild is remarkably similar. This finding in the grandmother and stability of her vision decreased from childhood permit us to propose that the tumor did not develop and even regressed with time.

Absence of the abducens nerve in Duane syndrome verified by magnetic resonance imaging.

PURPOSE: To demonstrate that currently available magnetic resonance imaging techniques may verify the absence of the abducens nerve in Duane syndrome. METHODS: We performed magnetic resonance imaging in a 36-year-old woman with left Duane syndrome, type 1, using spoiled gradient recalled acquisition in the steady state to obtain high-resolution T1-weighted images through the abducens nerve in its subarachnoid segment. Scans were obtained in the axial plane from the medulla to the midbrain and then reformatted along the plane of the abducens nerve. RESULT: Unilateral absence of the left abducens nerve was verified using magnetic resonance imaging. CONCLUSION: The absence of the abducens nerve in Duane syndrome can be verified by modern magnetic resonance imaging techniques.

Demonstration of exclusive cilioretinal vascular system supplying the retina in man: vacant discs.

PURPOSE: To report the fluorescein angiographic and Doppler ultrasonographic findings in a patient with apparent exclusive ciliary vascular supply of the retina of both eyes. METHODS: Case report. RESULTS: The ophthalmoscopic appearance of all arterial vessels emanating from both discs was consistent with a cilioretinal origin. Retinal veins also entered each disc peripherally near the margin, leaving the central part of each disc vacant. Fluorescein angiography showed filling of all arterial vessels simultaneous with the early-phase choroidal background flush bilaterally. Color and power Doppler ultrasonographic imaging demonstrated unequivocally the absence of central retinal vessels within the optic nerves. Both discs were normal in size and excavated with central glial tissue present. The clinical history of monocular, alternating episodes of failing vision with partial resolution and the retinal pigmentation patterns bilaterally were consistent with, though not conclusive for, previous episodes of serous retinal detachments. Coincident systemic anomalies consisted of small kidneys with reduced renal parenchyma discovered on ultrasonography, along with chronic interstitial nephritis. CONCLUSIONS: The ophthalmoscopic appearance of optic discs with apparent all-cilioretinal vascular supply has been reported previously, but proof of the absence of central retinal vessels requires Doppler ultrasonographic evidence corroborated by angiographic findings, as exemplified in our case report. We describe the association of this disc anomaly with renal parenchymal disease and its distinction from colobomatous defects.

Hemorrhage complicating YAG laser feeder vessel coagulation of cornea vascularization.

A neodymium:yttrium-aluminum-garnet (Nd:YAG) laser was used in the thermal mode to coagulate blood vessels in a patient with a vascularized corneal leukoma in an attempt to reduce neovascularization before penetrating keratoplasty. Occlusion of the feeder artery at the periphery was followed by a large stromal hemorrhage. A successful keratoplasty was performed 2 days later.

Endogenous systemic IFN-gamma has a protective role against ocular autoimmunity in mice.

Locally produced IFN-gamma has been implicated in enhancing inflammation and in promoting organ-specific autoimmunity. In the present study, we investigated the influence of systemically available IFN-gamma on the expression of experimental autoimmune uveoretinitis (EAU) induced in mice with the retinal Ag, interphotoreceptor retinoid binding protein (IRBP). EAU-susceptible B10.A mice treated with a mAb to IFN-gamma developed much more severe EAU than did the controls and had increased delayed hypersensitivity (DH) responses to IRBP. There was an increase in the proportion of macrophage/monocytes vs lymphocytes in the ocular lesions of treated animals. The anti-IFN-gamma treatment did not prevent expression of MHC class II within the ocular tissues. Conversely, treatment with rIFN-gamma ameliorated EAU expression and lowered DH responses. This occurred despite widespread induction of MHC class II Ag in the ocular tissues and other organs. In contrast to EAU and DH, serum antibody titers and lymphocyte proliferation to IRBP were not significantly affected by either treatment. Experiments in several genetically resistant strains of mice showed that treatment with anti-IFN-gamma was able to up-regulate disease expression also in some EAU-resistant strains. In the case of one such strain, resistance to EAU induction was completely abrogated by the treatment. We conclude that endogenously produced IFN-gamma at the systemic level acts to down-regulate EAU in the mouse and that IFN-gamma-related mechanisms may be involved in conferring resistance to EAU in some mouse genotypes.

Calf lung surfactant extract prophylaxis and retinopathy of prematurity.

Retinopathy of prematurity (ROP) is an important cause of blindness among extremely low birth weight infants (birth weight less than or equal to 1000 g). In the 1990s, greater numbers of extremely low birth weight infants will survive, in part due to routine surfactant replacement therapy for neonatal respiratory distress syndrome. Few studies have evaluated the effect of surfactant therapy on the incidence and severity of ROP. The authors performed a review of the records of extremely low birth weight infants born in two 2-year intervals before and after initiation of a clinical protocol in which all extremely low birth weight infants received prophylactic treatment with calf lung surfactant extract (Infasurf). Surfactant therapy was associated with a significant improvement in survival to discharge (79% [88 of 112] versus 63% [82 of 131]; P = 0.01). Compared with control infants, surfactant-treated infants had a significantly lower incidence of any stage of ROP (64% [56 of 87] versus 85% [68 of 80]; P less than 0.004). The incidence of threshold (Stage 3 plus or greater) ROP was substantially reduced (3.4% [3 of 87] versus 10% [8 of 80]; P = 0.16)). The surfactant-associated reduction in ROP was independent of birth weight, gestational age, race, or sex. These data suggest that Infasurf may substantially reduce the incidence and severity of ROP in the extremely low birth weight population.