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Biomedical subjects

D Friedburg

Publications and source records attributed to D Friedburg.

At least 37 records · Page 2Linked to original sources
PubMed1981

[Stereoscopic vision with central scotomata (author's transl)].

Thirty-nine patients with convergent microstrabismus and 24 patients with central organic scotoma underwent measurements of stereo acuity. Stereopsis at distance was measured by means of a polarization haploscope using "plane-tests" and random dot tests respectively. For near stereopsis were used commercially available tests (Titmus Test, TNO-Test). Organic scotomata can be divided into "circumscribed central scotomata" and "sievelike scotomata", the latter leading to poorer performance in random dot tests. Large plane tests yielded better results than small ones. In microstrabism we found stereo acuities similar to those of patients with "sievelike scotoma". The results support the theory of displacement of fusion within Panum's area in microstrabismus leading to decreased local stereopsis due to decreased concentration of stereo units at the border of Panum's area.

Depth Perception↗
PubMed1980

[Decreasing local stereopsis with increasing horizontal disparity, indicating decreasing density of binocular cortical projection towards the limits of Panum's area (author's transl)].

Measuring local stereopsis by means of random dot stereograms with increasing horizontal disparity, the relative density of binocular cortical projection has been determined at a distance of 75 min of arc from the fovea. The accuracy of stereoscopic perception decreased with increasing horizontal disparity. The reciprocal value of the error frequency was used to measure the density of binocular cortical projection. Panum's area at the above mentioned distance from the fovea can be constructed by plotting the error frequency against the horizontal disparity. We observed a decrease of the relative density of binocular cortical projection towards the limits of Panum's area without a sharp break. The results are in agreement with those reported by Bishop and Henry and Joshua in the cat (receptive field disparity). The theory of stereopsis as proposed by Bishop explains our findings well and may be transferred to binocular vision in man.

Depth Perception↗
PubMed1980

[Circular neovascularization of the circulus arteriosus iridis minor].

Vessel duplications of the anastomosis of the cirulus arteriosus iridis minor were observed in 15 patients with diabetes mellitus and in four patients with retinal venous occlusion, in a total of 1192 iris angiograms made. In each of these cases there is a bilateral neo-vascularization that may be regarded as an indication of a general vascular disease. It could be a fairly unaggressive process of new vessel formation in the iris which, during four years of observation, has in none of the cases observed developed into a rubeosis iridis visible under the slit lamp.

Adult↗
PubMed1979

[Abnormalities in the vessels of the iris as seen in fluorescein angiography (author's transl)].

There are unusually thick serpentine vessels in the iris along which there are no leaks in the fluorescein angiogram. Five and a half to seven years ago this was considered to be a sign of normal iris vessels in our department. It was assumed that this was only an abnormality. In four instances we have been able to find this irregularity, without any changes, in the vessels in the iris where it was a question of shunt vessels. In three of these four instances other diseases of the eyes were also present.

Aged↗
PubMed1979

[Bulbus motility in early and late surgery of orbital floor fractures (author's transl)].

Among 638 patients with fractures of the middle third of the facial skeleton 139 were found to have clinically relevant fractures of the orbital floor. 74 of them were followed up ophthalmologically and by x-ray examination. In 49 patients the results of the operative treatment were judged from a detailed questionnaire. Operation within 2 weeks after the accident yielded better results than later operation. Persisting motility disturbances concerned mainly the upper field of gaze.

Eye Movements↗
PubMed1978

Fluorescein angiography of the corneal limbus--drug effects on capillary blood flow.

By means of fluorescein angiography, plasma flow through the capillaries at the limbus corneae is demonstrated. The number of stained capillaries at a given time served as a measure of capillary perfusion. Even without drug the entire capillary system is perfused at least by plasma. Tolazoline enhanced the velocity of perfusion (P = 2alpha less than 0.01), epinephrine caused a marked capillary constriction (P = 2alpha less than 0.01), as well as--to a lesser extent--did dexamethasone (P = 2alpha less than 0.05). Dionine caused hyperemia, but the data varied much more than after tolazoline. In addition, dionine enhanced the dye leakage from the vessels.

Adult↗
PubMed1978

[Cyclofusion measurements for assessing the function of the oblique eye muscles (author's transl)].

In free space a random-dot-stereogramme for the determination of the extent of cyclofusion is used with the help of a haploscope. In the normal person orthophoria with regard to rolling to within +/- 1 degrees is found not only in the primary position but also in the secondary and tertiary positions and with head tilt. From the fact that with circular rotation of both eye images against each other pseudostereoscopic effects occur, it is deduced that the cyclofusion seen here occurred sensorially. The testing of the area of cyclofusion gives a very good basis for determining the indication for operation on the superior oblique muscle. It is shown with examples that simply tucking this muscle when old trochlear nerve paresis is present without provable excyclotropia is not favorable. Instead one must tuck the muscle asymmetrically in such cases--the fold should be markedly smaller at the anterior border of the muscle which acts more as a rotator, than at the posterior border.

Humans↗
PubMed1975

[Results of perforating keratoplasty in hereditary corneal diseases (author's transl)].

Operation results of keratoplasty in 50 eyes having keratoconus are presented and discusses. Furthermore a report is made on keratoplasty in cases of keratotorus in reticulate, maculate, and granulate dystrophies as well as in congenital ichthyosis with corneal involvement. The prognosis and complications of this intervention are presented.

Corneal Dystrophies, Hereditary↗