Mary G. Mehaffey

Visual Field Defects After Macular Hole Surgery

Purpose To describe a group of patients with dense visual field defects following macular hole surgery. Methods Nine (7%) of 125 patients reviewed noted onset of dense visual field defects following uncomplicated vitrectomy with gas-fluid exchange for the treatment of macular hole. Patient records were reviewed to investigate the etiology of these defects. Results Eight (89%) of nine eyes that had surgery for macular hole developed dense, wedgeshaped visual field defects in the temporal periphery. One eye had an inferonasal wedge-shaped defect extending to fixation. Seven (78%) of nine eyes had generalized or focal narrowing of the retinal arteriole extending into the area of retina corresponding to the visual field defect, and five (56%) of nine eyes developed mild to moderate segmental nasal optic disk pallor. Postoperative fluorescein angiography disclosed one eye with delayed filling of the retinal arteriole extending into the area of retina corresponding to the visual field defect. Vitrectomy specimens showed no evidence of nerve fiber layer or internal limiting membrane in eight (89%) of nine eyes. Conclusions Visual field defects can occur following vitrectomy and gas-fluid exchange for macular hole. The most common visual field defect is dense and wedge-shaped and involves the temporal visual field. Although unclear, the etiology may involve trauma to the peripapillary retinal vasculature or nerve fiber layer during elevation of the posterior hyaloid or during aspiration at the time of air-fluid exchange, followed by compression and occlusion of the retinal peripapillary vessels during gas tamponade.

The microcirculation of choroidal and ciliary body melanomas

The microcirculation of ciliary body and choroidal melanomas is remodelled into patterns. The presence of microvascular networks, composed of back-to-back loops that encircle microdomains of tumour, and parallel vessels with cross-linking, are associated with death from metastatic melanoma. The formation of these complex vascular patterns may result from reciprocal interactions between the tumour cell and the extracellular matrix, and pattern formation may reflect an invasive tumour cell phenotype. Ciliary body and choroidal melanomas are among the few forms of cancer treated before a pathologist assigns a grade to indicate whether tumour is likely to follow a benign or aggressive course. There is evidence to suggest that prognostically significant microcirculatory patterns may be detectable by non-invasive imaging techniques that may provide a substitute for biopsy to guide the clinical management of patients with these sight- and life-threatening tumours.

Correlation of ultrasound parameter imaging with microcirculatory patterns in uveal melanomas

Previous studies demonstrated a correlation between acoustic backscatter parameters and survival in ocular melanoma. The histologic presence of microvascular networks in ocular melanoma is also associated with death from metastases. This study tests the hypothesis that melanomas grouped on the basis of these microvascular patterns are separable by ultrasound spectrum analysis. We scanned 40 melanomas using a 10-MHz ultrasound unit equipped for digitization of radio frequency data. After enucleation, tumors were sectioned in planes corresponding to the ultrasonographic examination and stained to demonstrate microcirculation. Acoustic spectral parameters were compared between 14 melanomas with a nevuslike microcirculation and 26 with foci of high-risk microvascular structures. Smaller scatterer size, lower acoustic concentration and greater spatial variability were found to correlate with high-risk microvascular patterns and areas of cystic degeneration. We suggest that nonvascular extracellular matrix components associated with microvessels may be responsible for the correlation of acoustic parameters with microvascular pattern and distribution.

Evaluation of infectious crystalline keratitis with confocal microscopy in a case series.

We sought to determine whether there are unique findings in infections crystalline keratitis (ICK) examined by confocal microscopy and if confocal microscopy is predictive for bacteriology in ICK. A retrospective review of consecutive patients with a presumed diagnosis of ICK by slit-lamp examination was performed. These patients were then examined with confocal microscope and cultured. Sixteen patients were identified by biomicroscopy. Average age was 71 years; 12 of 16 patients were women; 10 of 16 had prior penetrating keratoplasty; and 12 of 16 were taking topical steroids. Confocal microscopy revealed a variable appearance to the crystals in the corneal stroma. Eight of 16 patients had distinct needle-like deposits at varying depths in the stroma, and eight had amorphous deposits grouped at different levels of the stroma. The results of confocal microscopic examination resembled the reported histopathology with clusters of deposits, but its current resolution does not allow identification of bacterial morphology. There was no correlation of morphology with culture results. Organisms were recovered in 12 of 16 patients by culture. In 10 of 16 patients, the infection was successfully treated with topical antibiotics, usually cefazolin. Crystal morphology of ICK can be observed by confocal microscopy. No pathognomonic, single pattern for this disease is seen with the confocal microscope. The latter may be an aid in determining the clinical response to treatment.

Microcirculation architecture of metastases from primary ciliary body and choroidal melanomas

PURPOSE To describe the microcirculation architecture of metastatic choroidal and ciliary body melanoma. METHOD Histologic sections of 35 metastases from 19 primary melanomas were stained to demonstrate microcirculation. RESULT The appearance of microcirculatory networks in metastases is independent of the target organ but associated with the size of the metastatic deposit (estimated coefficient = 0.5959; SE = 0.3024; P = .0488). CONCLUSION The microcirculatory patterns of primary uveal melanomas that are associated with metastatic behavior appear in foci of metastasis, regardless of the site of dissemination.

Relative Importance of Quantifying Area and Vascular Patterns in Uveal Melanomas

PURPOSE To test whether the cross-sectional area of choroidal and ciliary body melanomas and quantification of microcirculatory networks and parallel vessels with cross-linking are features associated with death from metastatic melanoma, and to compare new with conventional histologic prognostic features. METHODS The cross-sectional area of 234 ciliary body or choroidal melanomas was measured from digitized images of histologic sections. The percentage of cross-sectional area occupied by two microcirculatory patterns-networks and parallel vessels with cross-linking-was calculated for the 152 tumors containing at least one focus of either pattern. Kaplan-Meier survival curves were generated based on cross-sectional and percentage of cross-sectional areas of these patterns. Cox proportional hazard regression methods related time to death from melanoma with sets of predictor variables. For each model, percent variation explained was computed. RESULTS Patient survival differs significantly when tumors are classified based on cross-sectional area: small (<16 mm2), medium (> or =16 mm2 but <61.4 mm2), and large (> or =61.4 mm2). Patients with tumors containing networks and parallel vessels with cross-linking microcirculation patterns that occupy 2% of cross-sectional area have a significantly worse prognosis than do those patients with tumors containing a smaller percentage of these patterns. CONCLUSIONS Quantifying cross-sectional tumor area and the percentage area occupied by networks and parallel vessels with cross-linking microcirculatory patterns in ciliary body and cho. roidal melanomas provides significant prognostic information. Compared with more conventional prognostic characteristics, the most dramatic increase in prognostic information is provided by determination of the presence or absence of microvascular patterns.

Mapping the location of prognostically significant microcirculatory patterns in ciliary body and choroidal melanomas

The microcirculation of choroidal and ciliary body melanomas is remodeled into architecturally distinctive patterns. The presence of two histologic microvascular patterns, networks and parallel vessels with cross-linking, is strongly associated with metastasis. This study was designed to test the hypothesis that networks and parallel vessels with cross-linking patterns are not distributed evenly throughout the tumor. From a set of 234 eyes removed for ciliary body or choroidal melanoma, 152 tumors contained at least one focus of either vascular networks or parallel vessels with crosslinking. Histological cross-sections were digitized and foci of tumor containing these patterns were pseudocolorized so that their location within the periphery or central tumor zone could be mapped. Ciliary body and choroidal melanomas vary widely in size and shape and it is not appropriate to describe the periphery of a tumor as a fixed value because in a small tumor, the periphery thus defined would occupy a larger percent area than in a larger tumor. In this study, the peripheral and central zones of each tumor were described by a function that was constant from tumor to tumor, allowing the width of the peripheral and central zones to vary proportionally with tumor size. Observed counts of vascular patterns per zone were compared statistically with expected counts based upon the percent area occupied by the peripheral and central zones. Discrete foci of networks and parallel with cross-linking vessels are over-represented in the tumor periphery (p < 0.0001).

Distribution of prognostically important vascular patterns across multiple levels in ciliary body and choroidal melanomas

PURPOSE To investigate the validity of assigning patients whose eyes have been removed for ciliary body or choroidal melanoma to risk groups for metastasis based on the identification of microcirculatory patterns in one cross-section taken from the center of the tumor. METHODS Multiple levels were cut through the blocks of 15 ciliary body or choroidal melanomas until the tumor was exhausted. Each level was examined for the presence of microvascular networks and parallel vessels with cross-linking histologic features strongly associated with death from metastatic melanoma. RESULTS The central histologic section did not contain either microvascular networks or parallel vessels with cross-linking in eight tumors, nor were these patterns encountered in any of the more peripheral levels of the tumor. Seven tumors contained at least one focus of either microvascular networks or parallel vessels with cross-linking in the central histologic section. In two tumors, at least one of these patterns appeared in all histologic levels; in five tumors, at least one of these patterns appeared through multiple levels until just before the tumor was exhausted from the block (0.24 to 0.85 mm from the edge of the tumor). CONCLUSIONS This study suggests that the prognostic classification of uveal melanoma based on the histologic profile of the microcirculation may be consistent throughout the tumor depth.