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Biomedical subjects

W Aust

Publications and source records attributed to W Aust.

At least 19 recordsLinked to original sources
PubMed2000

The influence of elevated carbon dioxide and water availability on herbaceous weed development and growth of transplanted loblolly pine (Pinus taeda).

Loblolly pine (Pinus taeda L.) seedlings were grown in competition with native weeds using soil and seed bank collected from recently chopped and burned areas near Appomattox, Virginia. One-year-old seedlings were planted and weeds allowed to germinate from the native seed bank while being exposed to CO(2) (ambient and elevated - approximately 700 ppm) and water (water stressed and well watered) treatments for approximately one growing season in a greenhouse. Elevated CO(2) did not influence total weed biomass; however, C(3) weed community development was favored over C(4) weed community development in elevated CO(2) regardless of water availability. This suggests that weed community composition may shift toward C(3) plants in a future elevated CO(2) atmosphere. Pine growth was significantly greater in the well watered and elevated CO(2) treatments compared to the water stressed and ambient treatments, respectively, even though they were competing with native herbaceous weeds for resources. There was a significant water and CO(2) interaction for pine root:shoot ratio. Under elevated CO(2), root:shoot ratio was significantly greater in the water stressed treatment than the well watered treatment. In contrast, there was no significant difference in the root:shoot ratio under the ambient CO(2) treatment for either water treatment. These results suggest that loblolly pine seedlings will respond favorably in an elevated CO(2) atmosphere, even under dry conditions and competing with herbaceous weeds.

Journal Article↗
PubMed1997

[Modification of axial length and astigmatism by scleral buckling surgery].

BACKGROUND: Scleral buckling surgery for retinal detachment alters the shape of the globe resulting in changes of the refractive state of the eye. MATERIALS AND METHODS: In a prospective study of 52 eyes with retinal detachment we examined changes of corneal astigmatism and axial length induced by encircling buckling or segmental buckling spanning two quadrants. We compared our results with those found in literature. RESULTS: In most patients we found a shortening of the globe, rather in cases with encircling buckles than in the cases with segmental buckles (parallelly to the limbus). We also saw changes in astigmatism postoperatively in all patients. There was no statistically significant difference between patients with encircling and segmental buckles fixed parallelly to the limbus, neither in the change of axial length nor in the change of astigmatism. CONCLUSIONS: In all cases of scleral buckling procedures changes of corneal astigmatism and axial length are to be expected. So our results differ from those of other authors who did not always find a change of astigmatism. We suppose that the authors of the publications which differ from our results did not consider the change of the corneal axis by using the vector method.

Astigmatism↗
PubMed1994

[Late results of cataract operation with and without lens implantation in patients with uveitis].

Between 1985 and 1993, 73 eyes of 56 uveitis patients were subjected to extracapsular (n = 64) or intracapsular (n = 9) cataract extraction. We investigated the results up to 6 years later. 53 eyes received a posterior chamber lens, one an anterior chamber lens. Preoperatively, 22 eyes showed signs of an inflammation in the anterior chamber. Nevertheless, we implanted posterior chamber lenses in 16 of them. In most cases posterior synechias made the lens extraction more difficult, but no complications occurred. Twenty-four eyes, 17 of them with a posterior chamber lens, showed a new uveitis during follow-up which was treated conservatively. The intraocular pressure was not well regulated during follow-up in 4 of 15 eyes with preoperatively known secondary glaucoma. Two more secondary glaucomas developed. The visual acuity was satisfactory, and late diminutions were not caused by the uveitis in most cases. No artificial lens had to be explanted.

Adolescent↗
PubMed1994

[Effect of long-term lithium therapy on the pigment epithelium and optic nerve].

Morphological alterations of the retina caused by lithium have been described in rats. Human patients were therefore examined for such findings, and photophobia, neuritis affecting the optic nerves and downbeat nystagmus were observed. We found pathologic Arden quotients in the EOG, indicating an alteration of the pigment epithelium. The VEPs showed delayed latencies, whereas the amplitudes remained unchanged. Because of the pathologic electrophysiological findings ophthalmological controls, including EOG and VEP, should be performed yearly in patients taking lithium.

Adult↗
PubMed1991

[Synthetic lens implantation in cataract patients with glaucoma].

In 178 eyes (122 patients) with chronic glaucomas an extracapsular cataract extraction was performed in combination with an implantation of a posterior chamber lens. In 45 cases a filtrating glaucoma surgery had been performed before. A narrow pupil, caused by the miotic therapy, posterior synechias or changes after glaucoma surgery, made the cataract extraction difficult in most of the cases. The variations in the operation techniques which thereby became necessary are discussed. 0.5 to 4 years after the lens implantation visual acuity, visual field, ocular pressure and glaucoma medication were investigated. The postoperative results and the late results were very satisfying. Not only the increase of the visual acuity was essential especially for patients with defects of the visual field but also the therapeutic effect on the intraocular pressure. After the posterior chamber lens implantation significantly (p less than 0.001) more eyes had a well regulated intraocular pressure under 20 mmHg (87%) at the time of the late investigation than preoperatively (63%). 33% had to use the same medicaments as they had before, 2% had more, 64% less medicaments. Altogether 56% of the eyes did not need any topical therapy at the time of the late investigation. So even in the case of insufficiently regulated glaucomas we do no longer primarily perform an extracapsular cataract extraction together with the implantation of a posterior chamber lens combined with a goniotrephining surgery (Elliot-Fronimopoulos).

Ciliary Body↗
PubMed1990

[Squint operations for impaired motility due to endocrine ophthalmopathy].

In every case of an uncertain vertical diplopia one should think of an endocrine ophthalmopathy. A squint operation done in time will improve the motility of the eye. 8 of our 9 patients had no longer a diplopia after surgery and got binocular vision. 6 months after stabilization of the endocrine situation we resected and recessed the rectus muscles, especially the vertical rectus muscles, in 1 case we advanced the inferior oblique muscle. The amount of the surgical correction depended on the motility disturbance and the angle of squint which we compensated a few days before the operation by means of prisms. Postoperatively the patients got steroids parenterally.

Diplopia↗
PubMed1989

[Monocular and binocular vision following lens implantation in traumatic cataract].

Lens implantation after surgery for traumatic cataract is a major help in rehabilitating the patient. Most such patients are still at work. Surgical problems result from injuries to the cornea, iris, lens, and vitreous body. If possible a posterior chamber lens should be implanted in the bag. In 35 patients, 24 posterior chamber lenses and 11 anterior chamber lenses were implanted. In 27 cases the traumatic cataract had been caused by perforating injury and in eight by contusion. In 28 patients there was a significant improvement in visual acuity by the day they were discharged. At short focus more than one-half of the patients had simultaneous vision with striated glasses, and two-fifths at long focus. Two-fifths of all patients attained stereoscopic vision at both short and long focus. The binocular functions were worse in most of the cases where the visual acuity of the injured eye was 0.4 or less.

Adult↗
PubMed1988

[Ocular findings in tick borreliosis].

Tick-transmitted borreliosis is by no means a rare infectious disease. It is found especially in southern parts of Germany. Eyes are seldom affected. The disease can lead to nerve palsy of the eye muscles. One case of panophthalmitis and one of optic disk edema have been described. The authors found a bilateral palsy of the abducens nerve in one patient with tick-transmitted borreliosis. Motility normalized under therapy with highly-dosed penicillin.

Abducens Nerve↗
PubMed1988

[Eye position and function following late surgical correction of consecutive strabismus following primary tenotomy].

Even in patients with consecutive strabismus who had a partial or total tenotomy 10 to 50 years ago, reoperation is worthwhile. In 73% of the author's cases the squint angle was reduced to between -5% degrees and +5 degrees postoperatively; adduction or abduction were improved or normalized in 66%, convergence in 20%. In 29% simultaneous vision on a normal or slightly abnormal basis was achieved. Following dissection of scars and adhesions the tonotomied muscle was advanced and in some cases resected. If the squint angle was large, the antagonist was also recessed. In addition to preoperative diagnosis, which included prolonged compensation with prisms, the indication was affected by intraoperative findings.

Adult↗
PubMed1987

[Bilateral complete cryptophthalmos].

A case of bilateral complete cryptophthalmos combined with other malformations is described. The clinical appearance, histology, and the results of computed tomography and electro-ophthalmological investigations are communicated.

Abnormalities, Multiple↗
PubMed1987

[Light phenomena in the dislocation of artificial lenses in a model trial].

Light phenomena evoked by a Kratz elliptical posterior chamber lens, a Mark Choyce IX anterior chamber lens, and a four-loop Binkhorst anterior chamber lens were investigated in a model with pupils of various sizes. Besides monocular diplopia, the edge of the lens produces scattered light phenomena which vary according to the type of lens as well as the size of the pupil. It makes little difference whether the beam of light strikes the surface of the lens perpendicularly or at an angle of 30 degrees. Of the three lenses tested, the four-loop Binkhorst lens caused the most intense scattered light, due to the fixation of its haptic near its center.

Diplopia↗
PubMed1987

[Binocular function in patients with several years' interval between cataract operation on the first and second eye].

Investigation of the binocular functions in 25 patients with bilateral aphakia having undergone the two cataract operations at intervals ranging from 1 to 11 years. Only in 4 patients was the unilateral aphakia corrected temporarily by contact lenses. By the alternating cover test it was found that, after the second operation, 3 patients showed an esotropia and 14 an exotropia or exophoria for distant sight and 23 an exotropia or exophoria for near sight. Over one-third of the patients not having worn any contact lenses had no simultaneous vision at the Bagolini test for distant sight and more than half of them had no simultaneous vision for near sight. There was no stereoscopic vision for distant sight in nearly 50% of the patients and no stereoscopic vision for near sight in more than half of those who had not worn any contact lenses. The early fitting of contact lenses or the immediate lens implantation in elderly patients together with the prescription of spectacles for near work in the case of unilateral aphakia prevent the weakening or the loss of binocular functions.

Aged↗
PubMed1987

Defects of Descemet's membrane as a complication in cataract extraction with lens implantation.

As a complication of cataract extraction with lens implantation, a detachment of the Descemet's membrane can occur. In 1,163 eyes that were cataract operated during 1 year (1,060 extracapsularly--973 of them got a Kratz elliptical posterior chamber lens and 39 a Mark Choyce IX anterior chamber lens implantation--and 103 intracapsularly) 69 showed Descemet's detachments of a width of 0.5-2 mm, mostly located between 10 and 1 h. As a rule a reattachment is possible by air, Healon injection and rinsing with Ringer's solution. Normally, the peripheric clouded stroma and the edema of the epithelium regenerate postoperatively. Extensive Descemet's detachments lead to corneal dystrophy. The detachment of the Descemet's membrane is caused by intrusion of the instruments into the anterior chamber or by implantation of the lens.

Aged↗
PubMed1986

[Scattered light in implanted artificial lenses in a model trial].

The scattered light produced by 4-loop Binkhorst anterior chamber lenses, Kratz Elliptical posterior chamber lenses and Choyce Mark IX anterior chamber lenses were investigated in relation to different pupil diameters (1.5; 4.0; 6.0 and 8.0 mm) using a model. The light ray first met the anterior surface of the lens vertically and thereafter from 30 degrees to the left. The scattered light was photographically documented. The most scattered light was produced by the Binkhorst 4-loop anterior chamber lens and was caused by the fixation points of the loops near the centre of the lens. This was deduced from the fact that no scattered light could be seen if the pupil diameter was 1.5 mm, a situation one cannot find in a patient where the pupil is incapable of contracting to such an extent because of the loops. The Kratz Elliptical posterior chamber lens generally produced a minimum of scattered light. Increased glare sensitivity diminishing the ability to drive under mesopic conditions can be due to scattered light produced by artificial lenses.

Humans↗
PubMed1984

[Significance of early ophthalmologic detection of Fabry disease].

A case of cornea verticillata discovered by chance is reported; as a result of this finding, a mother and daughter were found to be heterozygous carriers of Fabry's disease. The ocular and internal symptoms as well as the biochemical analysis are discussed. Early ophthalmologic diagnosis is essential. The patient should be informed of the genetic risk.

Adult↗
PubMed1984

[Experiences with intracapsular cataract operation in myopic patients].

This paper reports on postoperative results and follow-up in 74 eyes of 51 patients suffering from myopia of between -5 and over -20 D. They underwent intracapsular cataract surgery for presenile or senile cataract. The operations were performed under local anesthetic after oculopression; a microscope was used. Only in 2 cases was there a loss of vitreous during the operation. After a 5-year follow-up a defect in the anterior membrane of the vitreous was found in 7 eyes. Forty-one eyes attained a visual acuity of between 0.4 and 1.0. Careful intracapsular cataract extraction by a skilled surgeon is justifiable for myopic patients. Degenerations of the periphery of the retina were easy to coagulate with the laser after the operation.

Aged↗