Biomedical subjects
Publications and source records attributed to H Freyler.
A follow-up study on 93 patients suffering from diabetic preretinopathy showed different courses of development. Predominantly occlusive types of microangiopathy were significantly more predisposed to a rapid progression of lesions than predominantly exudative types or occlusive exudative types. In addition, transition of one type into the other and reversibility of all symptoms were observed.
An electron microscopical study of vitreous structure in 14 eyes suffering from different types and durations of vitreous hemorrhages submitted to vitrectomy showed the typical stages of disintegration of erythrocytes. Neither the type (retrovitreal, intravitreal or combined retro- and intravitreal) nor the duration of the vitreous hemorrhages influenced the histological picture significantly. In cases of shrinkage of the vitreous body the collagen fibrillar meshwork showed normal periodicity of 640 A, partly split and irregular.
From the patients who underwent keratoplasty within the last three years we selected 40 out of a total of 121 with the following common features: diameter of the button 7.1 mm, indication for surgery for optical reasons, healing of the button with sufficient clarity, achieving visual acuity of 0.5 or better. In 20 patients we used a running 10/0 nylon suture; in the remaining 20 cases we combined single 8/0 silk sutures with a runing 10/0 prolene suture. No statistically significant difference between the two groups was found when corneal astigmatism was compared to six to eight months postoperatively (at least two months following suture removal). This also applied in respect of the resultant refraction difference. However, in cases of keratoconus the combined suture technique resulted in a lower degree of astigmatism than the running suture technique alone.
A report on our experience with cataract surgery on 20 patients who had undergone goniotrephination (after Fronimopoulos) one to three years (average 2.3 years) previously. In ten cases microsurgical preparation of the conjunctival and scleral flap revealed that the cleft was completely open; in four cases it was partially closed and in six cases totally occluded. In 16 cases, postoperative intraocular pressure was well regulated without additional medication. In two cases mitotic therapy was required for only six to eight weeks postoperatively to achieve normotonic values. In two further cases this regimen had to be followed indefinitely to achieve lasting pressure regulation.
In 169 out of 409 diabetic patients without any ophthalmoscopically or biomicroscopically visible retinal changes, typical symptoms of diabetic pre-retinopathy were revealed by fluorescein angiography: capillary dilatation (89.3%), capillary occlusion (78.7%), leakage from small blood vessels (54.4%) and arteriovenous shunts (40.8%). No correlation was found between the duration of the diabetes mellitus and the onset of diabetic pre-retinopathy. Juvenile diabetics developed significantly more capillary occlusions, while in diabetics of advanced age capillary occlusions and leakage from small vessels were encountered with almost equal frequency.
Twenty-five patients suffering from incipient cataract and diabetic retinopathy were submitted to cataract extraction. The intention was not only to improve visual acuity but also to permit better follow-up by fluorescein angiography and useful treatment by xenon light or laser coagulation. Postoperative complications were no more common than in nondiabetic patients, and a comparison with nine cases who refused surgery showed that the diabetic retinopathy was managed better in the aphakic eyes in respect of visual acuity and diabetic fundus changes.
In 185 diabetics with proliferative diabetic retinopathy (d.r.) involving both eyes symmetrically we analyzed the indication for photocoagulation in borderline cases in which, despite complications (such as inducement of vitreoretinal retraction), the beneficial effect of photocoagulation outweighs the likelihoood of a spontaneous deleterious course. In stage 2 of proliferative d.r. the risks associated with photocoagulation (i.e., factors likely to cause traction phenomena) were found to be extensive coagulation of intraretinal and preretinal hemorrhages, and coagulation of feeder vessels as well as of fundus areas located behind vitreal hemorrhages. In stage 3, procoagulative risk factors in the morphological picture comprised the existence of several vitreoretinal insertions with tent-shaped traction folds and extensive preretinal and subvitreal hemorrhages.
In 40.8% of 169 eyes affected with diabetic preretinopathy (verified by fluorescein angiography) arteriovenous shunt vessels were found. These vessels occur with significant prevalence in eyes with areas of retinal capillary occlusions, and in cases with diabetes of long duration. There is strong evidence that AV shunts are a consequence of the occurrence of areas lacking capillary perfusion in the retina.
This paper concerns experience gained by the authors with implants utilized during the past six years at the 1st University Eye Clinic, Vienna, in surgical treatment of 704 cases of rhegmatogenous retinal detachment: in 493 procedures a scleral buckle (silastic sponge in 81%) was applied, in 211 cases an encircling element (a silicon rod 2 mm in diameter in 83%). The subretinal fluid was drained in 52% of the buckling procedures, and in 90% of the encircling procedures. The success rate was 93% in the cases treated by buckling, and 79% following an encircling procedure. Thirty-four cases exhibiting massive periretinal proliferation and three cases with giant ears extending over 180 degrees were treated by retinopexy and indentation of the scleral wall in combination with vitrectomy followed by insufflation of SF6 gas. In 13 of these cases (two of them with giant tears) an anatomical cure was achieved.
Ninety-three patients with typical symptoms of diabetic preretinitis were kept under observation for three to five years (on average 3.9 years), and examined by fluorescein angiography at least once a year. The progress of the various individual symptoms, such as capillary occlusions, pigment extravasation from small vessels, microaneurysms and AV shunts was statistically significant in patients suffering from a predominantly occlusive form of diabetic preretinitis. Hence, more rapid progression of changes must be expected in such patients thn in those suffering from exudative forms.
Within the last five years 42 patients presenting with central serous retinopathy underwent argon laser photocoagulation. Both the plan of treatment and the evaluation of therapeutic success were based on the fluorescein angiogram.
Within the past 3 years intravitreal injection of SF6 gas was performed in 31 vitreoretinal surgical procedures. In 29 cases an additional vitrectomy was performed, and in 10 cases with massive periretinal proliferation (MPP) epiretinal membranes were stripped. The rate of success following intravitreal injection of SF6 gas as an adjunct to buckling procedures in severe cases of rhegmatogenous retinal detachment was 83%, as an additional measure in cases with giant tears extending over 180-225 degrees, 75%, in cases of tractional detachment due to preretinal and transvitreal strands, 60%, and in cases with MPP, 30%.
Forty patients successfully operated on for retinal detachment involving the macula were followed up for periods ranging from six months to nine years. The follow-up examination included testing for visual acuity, color perception and metamorphopsias, as well as biomicroscopy and fluorescein angiography. Postoperative visual acuity was correlated with the preoperative duration of retinal detachment. As expected, visual outcome was reduced in cases with lesions demonstrated by biomicroscopy and/or fluorescein angiography. In some patients visual acuity and color perception were impaired and metamorphopsias were present, even though the macula appeared normal in funduscopy and fluorescein angiography. This may be due to a possible misalignement of the photoreceptors as demonstrated in the owl monkey by Machemer.
Within the past 12 months, 64 intraocular lenses were implanted. Only eyes close to emmetropia and not exhibiting any pathological condition were considered for this type of surgery. The average age of our patients was 76 years. Preoperative medication and surgical procedure are described. Serious postoperative complications have not been observed so far. Striate keratopathy (in 22% of the cases), as well as secondary glaucoma (in 11% of the cases) were restricted to the initial 4-5 postoperative days. In 73% of the cases the postoperative visual acuity was 6/8-6/6. Maculopathy and opacification of the posterior lens capsule left behind were responsible for reduced visual acuity in the remaining cases.
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Thirty-two patients suffering from branch vein occlusion were divided into three groups according to their fluorescein-angiographic lesions. In cases of venous stasis retinopathy with an intact perifoveal capillary arcade, spontaneous resolution may be expected. In eyes affected by hemorrhagic retinopathy the prognosis after laser coagulation was better than for untreated eyes.
By means of fluorescein-angiography diabetic microangiopathy can be earlier revealed than by means of ophthalmoscopy. 36 children with diabetes (aged 6,25-15,5 years, x 11,6 years) with a duration of the diabetes between 0 and 12,75 years (x 3,9) were submitted to fluorescein - angiography, in 20 cases a follow up study was performed. Pathological changes were found in 21 cases, in 10 of 15 children with normal angiograms the duration of the disease was less than 5 years. More than 50% of all patients followed up showed an increase of diabetic microangiopathy.
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