Anterior capsular opacification: is aqueous the culprit?
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Aqueous Humor↗
Biomedical subjects
S C Gieser
Publications and source records attributed to S C Gieser.
Assessment of potential contrast sensitivity. Part I: Preoperative prediction of contrast sensitivity following intraocular lens implantation.
Preoperative contrast sensitivity functions (CSFs) were determined for 15 cataract patients using laser-generated patterns that effectively bypassed the optical components of the eye. These functions were compared with postoperative CSFs determined using traditional methods by transmission through the optics of the eye. Accurate prediction of postoperative contrast sensitivity occurred in 91% of the cases (ten of 11) for patients with preoperative visual acuity of 20/200 or better and in 67% of all the cases (ten of 15). Prediction failures occurred when the laser interferometer was not able to penetrate the cataract or when postoperative complications occurred. These results suggest that preoperative measurement of laser interferometric CSF is a useful predictor of postoperative CSF for patients with mild to moderate cataracts that can be bypassed by the laser and with better than 20/200 preoperative visual acuity. The problem of assessment when lens opacity is advanced is addressed in Part II.
Aged↗
Assessment of contrast sensitivity. Part II: The relationship between objective lens opacity and laser interferometric contrast sensitivity in the cataract patient.
The laser interferometer can effectively bypass the optics of the eye and measure retinal function in patients with immature cataracts. However, it is not known how much laser interferometric measurements are impaired by cataract density. In this study we compared objective lens opacity using the IntraOptics opacity lensmeter with contrast sensitivity (CS) measured by a Randwal He-Ne laser interferometer. Comparison of lens opacity with CS in the cataract population revealed an inverse linear relationship between objective lens opacity and retinal contrast sensitivity. Separation by cataract type showed correlation coefficients as high as -0.91 for nuclear sclerotic predominant cataracts and as low as no significant correlation for posterior subcapsular predominant cataracts. Comparisons of before and after implantation surgery contrast sensitivities (as measured by the laser interferometer) with preoperative lens opacities (as measured by the IntraOptics opacity lensmeter) quantified the extent to which laser interferometric measurements underestimated potential retinal function. We found that for all cataracts, other than posterior subcapsular predominant cataracts, potential contrast sensitivity (in decibels) was underestimated by about 0.2 to 0.3 times the opacity measured by this technique.
Adult↗
Hemangiopericytoma of the ciliary body.
A 60-year-old woman had a ciliary body tumor that resembled an amelanotic malignant melanoma by clinical examination. The magnetic resonance imaging scan correlated with the clinical diagnosis. Because of apparent rapid growth, her eye was enucleated. However, histopathologic examination revealed a highly vascularized, spindle-cell tumor harboring immunoreactive actin and vimentin. Electron microscopy further supported the diagnosis of hemangiopericytoma with smooth-muscle differentiation. To our knowledge, this is the first report of a hemangiopericytoma of the ciliary body.
Ciliary Body↗
Self directed learning: wisdom from independent study programs.
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Costs and Cost Analysis↗
Phthisis bulbi after intraocular lens implantation in a child.
A 4-year-old boy with trisomy 21 and a congenital cataract underwent cataract extraction and implantation of an iris-supported intraocular lens (IOL). Four years later the implant dislocated anteriorly and had to be removed. Now, 11 years postoperatively, the eye is blind, painful and shrunken. IOL implantation in infants and children is theoretically justified to preserve vision, reduce amblyopia and preserve fusion. The use of modern posterior chamber IOLs, especially when implanted in the lens capsular bag (if technically feasible), could reduce the risk of complications. However, until further data are accumulated, a conservative approach is warranted.
Blindness↗
Melanocytoma: nomenclature, pathogenesis, natural history and treatment.
A melanocytoma (magnocellular nevus) is a benign pigmented tumor that may arise wherever uveal melanocytes are present. The most commonly observed site is on or adjacent to the optic nerve head. In the past this tumor was frequently misdiagnosed as a malignant melanoma and many unnecessary enucleations were carried out. Its clinical features are now well recognized and, fortunately, specimens of melanocytomas are rarely received in ocular pathology laboratories today. A review of the literature concerning this tumor is presented, with special reference to the changing concepts in nomenclature, pathogenesis, natural history, and treatment that have evolved in the past one hundred years. We also define the clinical and histopathological features of this tumor.
Cell Transformation, Neoplastic↗