Comparison of the 20-MHz ultrasound probe with ultrasound biomicroscopy in glaucoma.

The 20-MHz ultrasound probe was compared with ultrasound biomicroscopy to determine its usefulness in imaging various glaucomatous conditions. Ten patients with glaucoma underwent anterior segment imaging with both the 20-MHz probe, which attaches to the I3 B-scan (Innovative Imaging Inc., Sacramento, CA), and the Ultrasonic BioMicroscope (UBM; Paradigm Medical Industries, Salt Lake City, UT). All pathology was easily demonstrable using the 20-MHz probe, in one case showing a retinal detachment not seen with the UBM. However, anterior findings such as fluid in the suprachoroidal space and sclerostomy sites in postoperative trabeculectomy cases were more difficult to view with the 20-MHz probe. The use of coupling enhanced the quality of the latter images. The 20-MHz ultrasound probe may be a viable aid in diagnosis and follow-up of certain glaucomatous conditions, and the use of a coupling device enhances its images.

Surgical management of secondary glaucoma after pars plana vitrectomy and silicone oil injection for complex retinal detachment.

OBJECTIVE: To evaluate the outcomes of surgical intervention for secondary glaucoma after pars plana vitrectomy and silicone oil injection for repair of complex retinal detachment. DESIGN: Retrospective noncomparative interventional case series. PARTICIPANTS: Forty-three eyes of 43 patients who underwent incisional surgery for secondary glaucoma after pars plana vitrectomy and silicone oil injection for repair of complex retinal detachment over a 9-year period. MAIN OUTCOME MEASURES: Intraocular pressure (IOP), intraoperative and postoperative complications, visual acuity, and the need for further surgical intervention for glaucoma. Success was defined as IOP < or =21 mmHg and > or =5 mmHg with or without medication but without surgical reoperation for glaucoma. RESULTS: Findings associated with elevated IOP included emulsified oil in the anterior chamber (n = 14), pupillary block from silicone oil (n = 13), open-angle glaucoma without silicone oil in the anterior chamber (n = 9), and angle-closure glaucoma without pupillary block (n = 7). The mean (+/- standard deviation) IOP was 41.4 +/- 15.1 mmHg before surgery for glaucoma and 17.2 +/- 10.2 mmHg after an average follow-up of 19.6 months (P < 0.001). Cumulative success was 69%, 60%, 56%, and 48% at 6, 12, 24, and 36-months respectively. In patients who underwent silicone oil removal alone for surgical management of glaucoma (n = 32), 11 of 12 IOP failures (92%) were due to uncontrolled IOP, whereas most IOP failures in the group who underwent silicone oil removal plus glaucoma surgery (n = 8) failed because of hypotony (3 of 4, 75%, P = 0.027). Of three patients who underwent glaucoma surgery alone to control IOP, one failed because of hypotony. There was no significant change in visual function at last follow-up (logarithm of the minimum angle of resolution [logMAR] 2.01) compared with preoperative visual function (logMAR 2.07, P = 0.74). CONCLUSION: Surgical management of secondary glaucoma after silicone oil injection for complex retinal detachment may achieve good IOP control and stabilization of visual function in most patients. Patients who undergo silicone oil removal alone to control IOP are more likely to have persistent elevation of IOP and possibly undergo reoperation for glaucoma, whereas patients who undergo concurrent silicone oil removal and glaucoma surgery are more likely to have hypotony.

A randomized trial of the long-term effects of digital ocular compression in the late postoperative period.

PURPOSE: To determine whether digital ocular compression is a viable technique to lower intraocular pressure in patients at least 3 months after trabeculectomy. PATIENTS AND METHODS: A 6-month prospective, randomized, controlled, single-masked trial of 29 patients who underwent a trabeculectomy at the Glaucoma Service of Wills Eye Hospital. Patients were assigned to two groups: ocular compression or cheekbone compression (control group). The ocular compression group performed compression to the operated eye three times a day in the pattern of 10 seconds of pressure, 5 seconds of rest, and 10 seconds of pressure. Pressure was applied with the index finger through the closed lid to the center of the cornea. Pressure was steady and firm, but not painful. No massaging was performed. The cheekbone compression group applied pressure to the zygomatic arch with an identical style and frequency. RESULTS: At 6 months, the change in mean intraocular pressure for the ocular compression group was 0.25 mm Hg compared with -0.44 mm Hg for the control group (P = 0.7). A few patients in both groups experienced large swings in intraocular pressure and mild to moderate discomfort. CONCLUSION: Ocular compression had little to no success in the long-term management of increased intraocular pressure in the late postoperative period in this study.

Excision of multiple eyelid apocrine hidrocystomas via an en-bloc lower eyelid blepharoplasty incision.

A 39-year-old man presented with upper and lower eyelid apocrine hidrocystomas that had recurred after each of three prior attempts at excision. These multiple, cystic tumors were adherent to the epidermis, thus precluding complete dissection and excision of each individual lesion. We report a surgical technique using a lower eyelid blepharoplasty incision to remove the confluent tumors of the lower eyelids en-bloc. We paid careful attention to both removing the lesions without rupturing the cysts and to achieving adequate depth of excision. Histology revealed features typical of apocrine hidrocystomas. The patient has remained free of recurrence three years since the en-bloc excision of the lesions.

Elevated intraocular pressure and hypotony following silicone oil retinal tamponade for complex retinal detachment: incidence and risk factors.

OBJECTIVE: To evaluate the incidence of and risk factors for persistently elevated intraocular pressure (IOP) and hypotony in patients who have undergone pars plana vitrectomy with silicone oil injection for the management of complex retinal detachment. SUBJECTS AND METHODS: The medical records of 532 patients who underwent silicone oil injection for the management of complex retinal detachments between January 1, 1991, and December 31, 1996, at the Bascom Palmer Eye Institute, Miami, Fla, were reviewed. Elevated IOP was defined as elevated IOP requiring an operation at any time postoperatively or a persistently elevated IOP of greater than 25 mm Hg at or after the 6-month visit. Hypotony was defined as a persistent IOP of 5 mm Hg or less at or after the 6-month visit. Patients with transient perioperative IOP fluctuations were not counted. RESULTS: Survival analysis for patients without cytomegalovirus retinitis (n = 383) revealed that 12.9% had an elevated IOP and 14.1% had hypotony by 6 months, 21% had an elevated IOP and 20.3% had hypotony by 1 year, and 29.5% had an elevated IOP and 27.3% had hypotony by 2 years. Among patients with cytomegalovirus retinitis (n = 149), none had a persistently elevated IOP, 10% had hypotony by 6 months, and 5.9% had persistently elevated IOP and 10% developed chronic hypotony by 1 year. A history of glaucoma before silicone oil retinal tamponade (P = .03), diabetes mellitus (P = .02), and a high IOP on the first postoperative day (P = .006) were risk factors for elevated postoperative IOP in patients without cytomegalovirus retinitis. Risk factors for postoperative hypotony in patients without cytomegalovirus retinitis included preoperative hypotony (P<.001) and aphakia (P = .03). CONCLUSIONS: An elevated or low IOP often develops postoperatively in patients without cytomegalovirus retinitis who undergo silicone oil injection for the management of complex retinal detachment. Risk factors for an elevated postoperative IOP include a history of glaucoma, diabetes mellitus, and a high IOP on the first postoperative day. Risk factors for hypotony include preoperative hypotony and aphakia.

Blood-retinal barrier breakdown in retinitis pigmentosa: light and electron microscopic immunolocalization.

Macular edema can contribute to visual loss in the retinitis pigmentosa (RP), but the sites and mechanism of blood-retinal barrier (BRB) breakdown leading to macular edema are not known. An understanding of the mechanisms involved could lead to the design of effective pharmacologic therapy to prevent or minimize macular edema in RP. To investigate this problem, immunohistochemical staining for albumin was performed on paraffin sections of 22 normal and 29 RP-affected eyes. Specimens were graded for extent of albumin extravasation in different regions of the retina, optic nerve head, ciliary body, and iris. Electron microscopic immunocytochemical staining for albumin was performed on an additional 6 normal and 9 RP-affected eyes. Two-thirds of the eyes from patients with RP and no other ocular disorders demonstrated extravascular albumin in the inner portion of the posterior retina. This was evident even in the absence of cystoid macular edema (CME), but eyes that had CME showed extensive BRB failure. In some cases, passage of albumin from the choroid to the retina was prevented even in the absence of the retinal pigment epithelium (RPE). Electron microscopic immunocytochemistry revealed that albumin permeated retinal vascular endothelial cells and RPE cells that showed degenerative changes in RP.

Magnetic resonance imaging measurement of gray matter volume reductions in HIV dementia.

OBJECTIVE: The authors recently reported smaller basal ganglia volumes for patients with HIV-associated dementia than for HIV-infected patients without dementia and a seronegative comparison group. The purpose of the current study was to determine whether HIV dementia is associated with volume reductions in other brain regions. METHOD: The authors measured volumes of CSF and gray and white tissue on cranial magnetic resonance images from homosexual men who were 1) infected with HIV with HIV-associated dementia complex, 2) infected with HIV without dementia, and 3) HIV seronegative. RESULTS: Results suggest that loss of white matter occurs with HIV infection and is more severe in HIV-positive patients with dementia than in those without dementia. There was some generalized volume reduction in gray matter in HIV-positive demented patients, although group differences did not reach significance when adjusted for age. Volume of posterior cortex, however, was significantly smaller among HIV-positive patients with dementia than in either remaining group. There were no significant differences between HIV-positive nondemented patients and HIV-negative subjects in these regions. CONCLUSIONS: In conjunction with findings from previous research, the authors conclude that HIV dementia is associated with specific gray matter volume reduction in basal ganglia and posterior cortex, as well as with generalized volume reduction of white matter.

Isoforms of platelet-derived growth factor and its receptors in epiretinal membranes: immunolocalization to retinal pigmented epithelial cells.

Epiretinal membranes (ERMs) form on the inner surface of the retina in conjunction with various ocular disease processes, but the factors controlling their development are not understood. The predominant cell types involved are retinal pigmented epithelial (RPE) cells and retinal glia. Cultured RPE cells secrete platelet-derived growth factor (PDGF), which is chemotactic and mitogenic for both RPE cells and retinal glia and, therefore, could be involved in the development of ERMs. In the present study, we performed immunohistochemical staining for PDGF A chain (PDGF-A), PDGF B chain (PDGF-B), and both types of PDGF receptors (PDGFr alpha and PDGFr beta) on ERMs associated with various disease processes. PDGF-A is detected in most ERMs, regardless of the associated disease process, and it appears to be localized predominantly in RPE cells, recognized by the presence of pigment and the immunohistochemical demonstration of some or all of the following RPE-associated epitopes: class III beta-tubulin, keratin, the 65-kDa microsomal protein recognized by the RPE9 antibody, and cellular retinaldehyde-binding protein. PDGF-B is found only in minor subpopulations of cells in about half of the ERMs evaluated and, with only occasional exceptions, appears to be localized almost entirely in blood-borne cells found in and around vessels in vascularized ERMs. Both PDGFr alpha and PDGFr beta are demonstrated in most ERMs with neither isotype consistently predominating: they are found predominantly on RPE cells with many cells expressing both receptor types. ERMs with little or no RPE cell component contain little or no PDGF and PDGF receptor, whereas those in which the RPE cell represents the major cell type, have widespread PDGF and PDGF receptor positivity. These findings show that RPE cells in ERMs produce PDGF-A and PDGF alpha and PDGF beta receptors and suggest that autocrine and paracrine stimulation with PDGF may be involved in ERM pathogenesis.

Platelet-derived growth factor is an autocrine growth stimulator in retinal pigmented epithelial cells.

The retinal pigmented epithelium (RPE) plays a major role in normal and exaggerated retinal wound repair; the latter can result in epiretinal membrane formation and loss of vision. The RPE forms a stable monolayer of highly differentiated cells that proliferates only during wound repair. The mechanism underlying the change to the proliferating phenotype is unknown. When grown on a plastic substratum, cultured RPE cells mimic the proliferating phenotype in situ; they escape density arrest and proliferate in serum-free medium. In this study, we have demonstrated that a platelet-derived growth factor (PDGF) autocrine loop is involved in RPE growth in serum-free medium, because: (1) RPE cells secrete PDGF into their media and express PDGF receptors; (2) the PDGF receptors on RPE cells are autophosphorylated in serum-free medium and suramin, an agent that displaces PDGF and other growth factors from their receptors, blocks the autophosphorylation; and (3) a neutralizing antibody to PDGF significantly decreases RPE growth in serum-free medium. When a linear scrape is made in an RPE monolayer, the cells migrate and proliferate to fill in the gap mimicking wound repair in situ. Cells along the edge of the scrape show increased expression of PDGF and PDGF-beta receptors, and increased staining for proliferating cell nuclear antigen. Immunohistochemistry and in situ hybridization demonstrate expression of PDGF in ganglion cells and cells of retinal blood vessels. PDGF is not detected in the outer retina or RPE in untreated eyes, but is detected in RPE participating in wound repair, either adjacent to laser burns or underlying retinal detachment. PDGF and PDGF receptors are also expressed in RPE in epiretinal membranes removed during vitreous surgery. These data suggest that PDGF is an autocrine stimulator of growth in RPE that plays a role in retinal wound repair and epiretinal membrane formation.

The natural history and results of treatment of superior oblique myokymia.

OBJECTIVE: To investigate the clinical presentations and long-term course of patients with superior oblique myokymia (SOM). METHODS: The medical records of all 16 patients with the diagnosis of SOM seen in the Neuro-Ophthalmology Unit of The Wilmer Ophthalmological Institute, The Johns Hopkins Hospital, Baltimore, Md, between 1976 and 1993 were reviewed. Follow-up information was obtained for 14 (88%) of the 16 patients. RESULTS: Of the 16 patients with SOM, nine (56%) were male and seven (44%) were female. The age of onset of symptoms ranged from 22 to 50 years (mean age, 34 years). All patients were otherwise healthy with no history of neurologic illness. Seven (44%) of the 16 patients complained of paroxysms of uniocular "shimmering," "fluttering," or oscillopsia lasting seconds, three (19%) complained of vertical and torsional diplopia, and six (38%) had both types of symptoms. Five (31%) of the 16 patients underwent neuroimaging studies within 1 year of onset of symptoms. All imaging study results were normal. Follow-up information was obtained for 14 patients (88%). The time from onset of symptoms to our most recent contact was 3 to 29 years. Of the seven patients who received no treatment, five (71%) continue to have symptoms to date. Three patients received medical treatment only; one of the three has experienced lasting benefit with carbamazepine. Four patients underwent superior oblique tenectomy combined with inferior oblique myectomy after not responding to medical treatment. All four patients experienced resolution of all ocular symptoms after surgery. CONCLUSIONS: Because SOM is a much more chronic disease than formerly realized and because of the poor long-term effects and potential side effects of the medications used, medical treatment of SOM is not the optimum way to manage the disease. Extraocular muscle surgery is the treatment of choice when symptoms of SOM are intolerable to the patient.

MR volume segmentation of gray matter and white matter using manual thresholding: dependence on image brightness.

PURPOSE: To describe a quantitative MR imaging segmentation method for determination of the volume of cerebrospinal fluid, gray matter, and white matter in living human brain, and to determine the method's reliability. METHODS: We developed a computer method that allows rapid, user-friendly determination of cerebrospinal fluid, gray matter, and white matter volumes in a reliable manner, both globally and regionally. This method was applied to a large control population (N = 57). RESULTS: Initially, image brightness had a strong correlation with the gray-white ratio (r = .78). Bright images tended to overestimate, dim images to underestimate gray matter volumes. This artifact was corrected for by offsetting each image to an approximately equal brightness. After brightness correction, gray-white ratio was correlated with age (r = -.35). The age-dependent gray-white ratio was similar to that for the same age range in a prior neuropathology report. Interrater reliability was high (.93 intraclass correlation coefficient). CONCLUSIONS: The method described here for gray matter, white matter, and cerebrospinal fluid volume calculation is reliable and valid. A correction method for an artifact related to image brightness was developed.

Reduced basal ganglia volume in HIV-1-associated dementia: results from quantitative neuroimaging.

Although brain atrophy is a common neuroradiologic and pathologic finding in patients with HIV-1 infection, especially those with HIV-1-associated dementia complex, it is not clear whether specific regions of the brain are differentially responsible for tissue loss. In this study, we measured volumes of basal ganglia structures on MRIs for three groups: HIV-1-infected homosexual men with HIV-1-associated dementia complex (HIV+ demented), HIV-1-infected homosexual men without HIV dementia (HIV+ nondemented), and noninfected homosexual men. All groups were comparable on age and years of education, and the HIV+ groups were comparable on level of immunosuppression. Total brain volume was smaller in the HIV+ nondemented patients in comparison with HIV- control subjects; the HIV+ demented patients demonstrated even smaller brain volumes than the HIV+ nondemented patients. Smaller basal ganglia volumes, after corrections for intracranial volume, distinguished HIV+ demented patients from the other two groups; there were no differences between the HIV+ nondemented and HIV- groups on basal ganglia volumes. This study suggests that HIV infection causes generalized brain atrophy, but that the clinical features of HIV dementia develop with selective basal ganglia atrophy, consistent with the characterization of HIV dementia as subcortical.