Karl C. Ossoinig

Terson's Syndrome: Clinicopathologic Correlations

In seven cases of Tersons syndrome, an elevated, dome-shaped, membrane was detected in the posterior pole by ophthalmoscopy, echography, or during pars plana vitrectomy. Light and electron microscopic examination of two additional eyes obtained postmortem from an acute case of Tersons syndrome revealed that the posterior vitreous face was elevated by blood and that the internal limiting membrane of the retina was intact and in its normal position. In two chronic cases, a dome-shaped epiretinal membrane was excised from the macula during vitrectomy. Light and ultrastructural studies demonstrated that the membranes consisted of glial cells and basement membrane material. The dome-shaped structure observed in eyes with Tersons syndrome is due to the formation of a subhyaloid hemorrhage. The partially detached posterior hyaloid face created by this hemorrhage provides a scaffold for cellular proliferation and the development of an elevated epiretinal membrane in long-standing cases. Echographically, this membrane resembles a retinal detachment in B-scans, but can be clearly distinguished from retina with standardized A-scan.

Choroidal Ganglion Cell Plexus and Retinal Vasculature in Monkeys with Laser-Induced Glaucoma

The choroid of primates possesses an elaborate nitrergic nerve fiber plexus containing a great number of ganglion cells. Postganglionic nerve fibers innervate mainly the choroidal vasculature. In addition, the choroid contains an elastic muscular system closely associated to the vasculature. The goal of the present investigation was to analyze how sustained IOP elevation would affect the choroidal vasculature with its specialized innervation and the adjacent retina. For this purpose the posterior eye segment of 15 rhesus monkeys which after laser coagulation of the trabecular meshwork developed elevated IOP up to 4 years were studied using immunohistochemical and histochemical methods, and scanning electron microscopy of corrosion casts. The most striking finding was a significant reduction of choroidal thickness and loss of choroidal ganglion cells and nerve fibers, especially in the central portion of the choroid. Corrosion casts of the choroidal vasculature showed a slight decrease in capillary density and a decrease in length of the arterioles in glaucomatous eyes. Whole mount preparations of the retina stained for NADPH diaphorase revealed a significant reduction in positively stained amacrine cells, reduction in diameter of arterioles and changes in the staining pattern of the retinal vasculature, particularly in the perimacular region.

Axial Length Changes after Retinal Detachment Surgery

A-scan echography was an accurate method for detecting changes in the depth of the anterior chamber, lens thickness, and length of the vitreous cavity after retinal detachment surgery in 30 eyes. Approximately 60% of the eyes had significant alterations in axial lengths exceeding+/-0.36 mm in aphakic eyes and +/-0.54 mm in phakic eyes. However, the operation of scleral bucklingg with large segments of hard silicone rubber implants or explants supported by an encircling band failed to result in a significant predictable shift of axial change in phakic or aphakic eyes. A-scan echography showed significant shallowing of the anterior chamber, and scleral buckling significantly increases lens thickness for at least six weeks. This induced a minor myopic refractive change that may explain some of the difference in postoperative refracitons between phakic and aphakic eyes.

Myositis of Extraocular Muscles Diagnosed with Standardized Echography

Disorders of extraocular muscles are a frequent cause underlying signs or symptoms of orbital disease, such as exophthalmos or double vision. In the Echography Service of the Department of Ophthalmology at The University of Iowa, 1321 patients with exophthalmos or other signs of orbital disease were examined during a 5-year period between February 1978 (date of first echographic diagnosis of orbital myositis) and February 1983. In 468 (35.4%) of the patients, a thickening of one or more extraocular muscles was the only or main cause of the orbital signs and symptoms. The majority of these cases had Graves’ disease. In 45 cases (3.4% of all orbital cases, 9.6% of the cases with thickened muscles), a myositis was diagnosed and treated.

Ophthalmic Features of Alagille Syndrome (Arteriohepatic Dysplasia)

Eight patients with Alagille syndrome (AGS) are reported. In addition to previously reported findings of posterior embryotoxon, pigmentary retinopathy, and choroidal folds, new findings include decreased axial eye lengths, small corneal diameters, and shallow anterior chambers. Optic disc swelling was noted ophthalmoscopically and abnormally increased orbital subarachnoidal fluid was detected through measurements of the arachnoidal diameters with standardized echography.

Standardized echography of the optic nerve

Standardized Echography, a special advanced method of diagnostic ultrasound in ophthalmology (Ossoinig [21]) has become an effective, clinically very useful and, at times, indispensable diagnostic aid in the evaluation of the orbital portion of the optic nerve. Standardized Echography provides by far the most precise and accurate measurements of the thicknesses of the optic nerve and its sheaths throughout their orbital course. This method also provides a unique opportunity to study the in vivo dynamics of the subarachnoidal fluid surrounding the optic nerve and thus gives invaluable insight into the mechanism of compressive optic neuropathy and of BIH, and adds tremendously to the clinical differential diagnosis of optic nerve and related disorders.

How to Obtain Maximum Measuring Accuracies with Standardized A-Scan

The standardized 7200 MA A-scan instrument of Kretztechnik can provide the most accurate ultrasonic measurements that are available. This is true for measurements of axial eye length and of any other normal or abnormal tissue thickness within the eye and orbit provided the correct procedures in calibrating the instrument, in displaying maximum signals at low “measuring sensitivity” and in taking the measurements from Polaroid pictures are followed. To obtain accurate clinical measurements, one other crucial requirement must be met: the distance to be measured must be properly identified first, i.e., an act of tissue identification must precede any measurement. Standardized A-scan is uniquely capable of providing such tissue identification. For this purpose, it is applied either at the very high standardized “tissue sensitivity” (e.g., for identifying the maximum diameter of a tumor or the maximum thickness of the optic nerve and the extraocular muscles) or at the low “measuring sensitivity”, e.g., for identifying the thickness of the retinochoroid layer (through perpendicularity of the sound beam at both the inner retinal and inner scleral surfaces) or for identifying the axial eye length (through optimal alignment of the acoustic beam with the axis of the globe). Standardized A-scan then accurately measures the identified distance, preferably at the low measuring sensitivity.

Perforating BB gun injuries of the globe

BACKGROUND AND OBJECTIVE To determine the visual and anatomic outcomes of eyes with perforating BB gun injuries. PATIENTS AND METHODS The authors reviewed the surgical management and final visual outcome of seven patients with BB gun-related perforating injuries of the globe seen by them between 1980 and 1995. Six patients underwent surgery, and one patient refused intervention and was lost to follow-up. Scleral buckles, lensectomies, and vitrectomies were performed in these six cases. RESULTS Five patients had a final visual acuity of 5/200 or better, with four patients achieving 20/200 or better and two of them having 20/70 or better. A posterior perforation involving the macula or an area temporal to the macula was associated with poor visual outcome. The visual acuity and the relative afferent pupillary defect at presentation or after the initial repair did not correlate with the final visual outcome. In addition, the presence of subretinal blood did not necessarily portend a poor prognosis in these young patients. CONCLUSIONS At least some eyes with perforating injuries can retain good visual acuity with aggressive surgical management using modern vitrectomy techniques. Visual acuity should not necessarily be used as the only exclusion criterion for intervention or enucleation.

Die Ultraschalldiagnostik der Tumoren in der Augenhöhle

Die Ultraschalluntersuchung wurde in kurzer Zeit zur sichersten Methode für die Diagnostik orbitaler Tumoren. Sie ermöglicht die genaue Bestimmung der Größe, Form und Lage der Tumoren und hilft so dem Operateur, den geeigneten Operationsweg zu wählen und die Operationsdauer abzuschätzen. Within a brief span of time ultrasonic examination has become the most reliable method for the diagnosis of orbital tumors. This method allows us to determine exactly the size, shape and location of the tumor; it helps the surgeon choose the proper approach and to estimate the time the operation will take.