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Biomedical subjects

Oliver Schwenn

Publications and source records attributed to Oliver Schwenn.

11 recordsLinked to original sources
PubMed2005

Deviations between transpalpebral tonometry using TGDc-01 and Goldmann applanation tonometry depending on the IOP level.

BACKGROUND: Recent comparisons between transpalpebral tonometry using TGDc-01 and Goldmann applanation tonometry were performed in populations with IOPs between 10 and 20 mmHg. The purpose of this study was to evaluate device deviations depending on different IOP levels (range 5-40 mmHg). METHODS: A total of 68 eyes of 68 patients were included and assigned to four IOP levels according to an initial applanation tonometry assessment: level I, <10 mmHg (n=8); level II, 10-19 mmHg (n=20); level III, 20-29 mmHg (n=20); and level IV, > or =30 mmHg (n=20). Two independent and randomized observers performed three replicate measurements per eye-observer 1 using TGDc-01 tonometry, and observer 2 using Goldmann applanation tonometry. Intraindividual deviations between measurement results were investigated concerning clinical relevance by medians and quartiles, concerning statistical significance by pairwise sign tests; p values <0.05 indicate local statistical significance. RESULTS: In patients with initial IOP > or =20 mmHg, TGDc-01-based tonometry significantly underestimated the IOP as based on Goldmann applanation tonometry (p<0.001). This effect increased with increasing IOP: IOP level III median difference (TGDc-01 - Goldmann) -1.3 mmHg (interquartile range, -2.5, -0.4), IOP level IV median difference -2.7 mmHg (-3.7, -1.0). In patients with initial IOP <10 mmHg, an at least gradual underestimation by TGDc-01 tonometry (p=0.219; median difference, -0.6, -1.6, 0) was observed. A total 18% of patients showed device deviations > +/-3 mmHg, and even 35% of those patients with initial IOP > or =30 mmHg. CONCLUSIONS: TGDc-01-based tonometry demonstrated an increasing underestimation of IOP with increasing IOP levels when compared with the current standard method of Goldmann applanation tonometry.

Aged↗
PubMed2005

Glaucoma studies from 1996 to 1999 in peer-reviewed journals.

BACKGROUND: Studies on glaucoma therapy were analyzed with regard to study design, diagnostic parameters and success criteria. MATERIALS AND METHODS: In 11 frequently read peer-reviewed periodicals, 101 studies published between 1996 and 1999 were chosen according to specific criteria. Design parameters, diagnostic measures and success criteria were investigated. RESULTS: Thirty-seven studies were retrospective and 64 prospective. Twenty-five studies were multicenter studies. Thirty-seven studies dealt with drug therapy, 12 with laser therapy, and 52 with surgical therapy. The study duration in 51% of the studies (n=52) was up to 1 year, in 28% (n=28) from 1 to 2 years, in 17% (n=17) over 2 years, and in 5% (n=5) in excess of 4 years. Four studies gave insufficient data. Forty-one studies recruited less than 50 patients and 57 studies recruited less than 75 patients. Thirty-four studies included more than 100 patients and 11 studies more than 250 patients. Sixty-one studies included race as a parameter. All 101 studies measured intraocular pressure (IOP). Forty-five studies explicitly described the method of tonometry. Thirteen studies measured a diurnal IOP. Forty-one studies examined the visual field, of which 30 named the method of perimetry. Only 28 studies examined the optic disc morphology. They all employed ophthalmoscopy, and two additionally employed optic disc photography. Sixty-three studies explicitly defined success criteria, establishing 95 different definitions: 74 definitions (78%) used a specified value for IOP as a success criterion. Out of the 70 definitions that gave an absolute value for IOP, 12 definitions (17%) used IOP values between 14 and 16 mmHg as the upper limit, 4 definitions (6%) used IOP values between 17 and 19 mmHg, and 54 definitions (77%) used IOP values between 20 and 22 mmHg. Out of the 26 definitions that specified a percentage IOP reduction, it was judged to be a success when the IOP was lowered by 20% or more from the starting value in ten definitions (38%), by 25% or more in three definitions (12%), and by 30% or more in 13 definitions (50%). CONCLUSIONS: Examples of prestigious studies show the necessity of observation periods of several years and demonstrate the need for a high number of participants, necessitating the cooperation of many study centers. Beside a more precise characterization of the patient collectives, clinical studies should always specify the measurement method clearly. Investigating a diurnal IOP profile to recognize changes in IOP and IOP peaks, as well as the routine determination of central corneal thickness, would be desirable. New diagnostic techniques for improved assessment of the functional and morphologic damage will gain in relevance in the future. The lack of a common definition of success reveals the complexity of the disease. However, an IOP reduction based on the degree of damage and ascertaining the target pressure seems sensible.

Databases, Factual↗
PubMed2004

Histological examination of an eye with endogenous Aspergillus endophthalmitis treated with oral voriconazole: a case report.

PURPOSE: To report the histological findings of an eye with severe Aspergillus endophthalmitis after oral treatment with voriconazole. METHODS. Case report. RESULTS: Histopathological examination revealed no fungal elements in choroidal or retinal vessels. The hyphae were mainly restricted to the vitreal side of the preretinal inflammatory infiltrate. Since the treatment with voriconazole had not been completed at the time of enucleation, the clinical course with potential further limitation or regression of the lesion remains unsettled. CONCLUSIONS: Endogenous Aspergillus endophthalmitis is a devastating condition often associated with immunodeficiency. The pathogenesis of this entity implies the primary invasion of choroidal and retinal vessels. The lack of antifungal drugs with high blood-ocular permeability results in an extremely poor visual prognosis. Our histological examination indicates promising activity and ocular penetration of the new antifungal agent voriconazole.

Administration, Oral↗
PubMed2004

[Heterochromia of the Iris after t-PA and Gas Injection of Sulfur Fluoride].

BACKGROUND: Are changes in iris colour and retinal pigment epithelium after t-PA and gas injection and subsequent vitreous haemorrhage caused by blood cells, or is this a toxic effect? CASE: A 81-year old female presented for vitrectomy with a persistent vitreous haemorrhage two months after t-PA and gas injection because of subretinal macular haemorrhage. Sonographic control revealed attached retina. The examination disclosed a new heterochromia of the iris with a change from blue to green-brown. A discrete anterior chamber flare and blood cells were found. Subsequent vitrectomy revealed a thick, rubber-like haemorrhage in the vitreous with suspect pigmentation. A change in retinal pigmentation was also evident. CONCLUSION: The cause for the heterochromia and the change in pigmentation of the retinal pigment epithelium remained unclear. It may have been a consequence of the persistent bleeding with iron apposition on the iris. A toxic effect of t-PA has to be discussed which led to the alteration in pigmentation.

Aged↗
PubMed2003

Toric phakic intraocular lens: European multicenter study.

OBJECTIVE: To evaluate safety, efficacy, predictability, stability, complications, and patient satisfaction after implantation of Artisan toric phakic intraocular lenses (TPIOLs) for the correction of myopia or hyperopia with astigmatism. DESIGN: Prospective, nonrandomized, comparative (self-controlled) multicenter trial. PARTICIPANTS: Seventy eyes of 53 patients (mean, 35 years; range, 22-59 years) with preoperative spherical equivalent between +6.50 and -21.25 diopters (D) and cylinder between 1.50 and 7.25 D. METHODS: Seventy eyes underwent implantation of a TPIOL with an optical zone of 5.0 mm (Artisan, Ophtec, Groningen, The Netherlands). The dioptric power of the intraocular lens was calculated by considering refraction, keratometry, and anterior chamber depth. The follow-up was 6 months in all cases. Lenses were available in powers ranging from +12.0 D to -23.5 D (spherical equivalent) in 0.5-D increments, with additional cylinder from 1.0 D to 7.0 D, also in 0.5-D increments. MAIN OUTCOME MEASURES: The main parameters assessed were best spectacle-corrected visual acuity (BSCVA), uncorrected visual acuity (UCVA), refraction, endothelial cell count (ECC), intraocular pressure, slit-lamp biomicroscopy, indirect ophthalmoscopy, subjective complaints, and patient satisfaction. RESULTS: Eyes were divided into group A, myopia (n = 48), with an average preoperative spherical equivalent of -8.90 +/- 4.52 D, and group B, hyperopia (n = 22), with an average preoperative spherical equivalent of +3.25 +/- 1.98 D. No eyes in either group experienced a loss in BSCVA, and 46 eyes gained 1 or more lines of their preoperative BSCVA. In 62 eyes (88.6%), UCVA was 20/40 or better. There was a significant reduction in spherical errors and astigmatism in all cases after surgery. All eyes of both groups were within +/-1.00 D of target refraction, and 51 eyes (72.9%) were within +/-0.50 D of target refraction. There was a 4.5% mean total loss of ECC during the first 6 months. No serious complications were observed. Overall patient satisfaction was very high. CONCLUSIONS: Six-month clinical trial results demonstrate that implantation of the Artisan TPIOL safely, predictably, and effectively reduced or eliminated high ametropia and astigmatism with one procedure. The refractive effect was stable at 6 months after surgery.

Adult↗
PubMed2003

Postoperative astigmatism and rotational stability after artisan toric phakic intraocular lens implantation.

PURPOSE: To evaluate deviations in the axis (intended versus achieved) and postoperative astigmatism after implantation of an Artisan toric phakic intraocular lens (IOL). SETTING: University Eye Hospital, Mainz, Germany. METHODS: This prospective study comprised 29 eyes with high ametropia and astigmatism. All eyes had uneventful implantation of a toric phakic IOL through a superior scleral tunnel incision at 12 o'clock. After a minimum of 6 months, the uncorrected visual acuity (UCVA), best correct visual acuity, refraction, and astigmatism were analyzed in all eyes. A multivariate analysis of postoperative astigmatism was performed. RESULTS: After a follow-up of at least 6 months, 95% of eyes were within +/-1.00 diopter (D) of emmetropia and 85% of eyes has a UCVA of 20/30 or better. The difference between the mean intended cylinder axis and achieved cylinder axis was 3.9 degrees (median 3 degrees; range to 13 degrees). The difference between the mean intended axis and the achieved axis between miosis and mydriasis was 1.8 degrees (median 1.5 degrees; range 0 to 5 degrees). The mean postoperative astigmatism after 6 months was 0.56 D with an axis of 31 degrees. Doubled-angle scatterplot analysis showed a tendency toward more flattening in the vertical meridian. CONCLUSIONS: During the 6-month follow-up, no significant rotation was observed after implantation of Artisan toric phakic IOLs to correct high ametropia. A sutureless sclerocorneal superior approach for phakic IOL insertion resulted in moderate to low astigmatism. Induced astigmatism should be taken into consideration during preoperative planning.

Adult↗
PubMed2003

[Complications following Molteno implant surgery: case report].

We present a 43-year old patient with refractory secondary glaucoma, who showed epithelial downgrowth into the anterior chamber following Molteno implant surgery. It will be discussed, whether the Molteno implant or the following keratoplasty, which was necessary because of corneal decompensation, caused the epithelial downgrowth.

Adult↗
PubMed2002

Long-term results of cataract surgery combined with trabeculotomy.

BACKGROUND: There are different surgical approaches for cataract and concomitant primary open-angle glaucoma (POAG). In a retrospective study we examined the long-term results of cataract extraction combined with trabeculotomy. PATIENTS AND METHODS: Between 1990 and 1997, 194 eyes with cataract and POAG were operated on in a combined manner. Eighty-eight eyes received a trabeculotomy (TT), in 82 eyes a trabeculectomy was added to the trabeculotomy (TT+TE) and in 24 eyes, in which probing of Schlemm's canal was impossible, standard trabeculectomy (TE) was performed. Pre- and postoperative intraocular pressure (IOP), glaucoma medication, and the intra- and postoperative complications of all patients were analyzed. RESULTS: Hyphema was the most common complication in the TT group (20.5%). Fibrin reaction occurred in 27.8% of all cases. There was no statistically significant difference in postoperative IOP between the TT group and the TT+TE group. A statistically significant decrease in IOP compared to preoperatively lasted 60 months in the TT group. In eyes with a preoperative IOP < or = 20 mmHg, none of the three procedures reduced IOP significantly (<20% of the preoperative IOP). In the first 2 years after operation 50% of the patients had no need for antiglaucomatous medication. CONCLUSIONS: Cataract surgery combined with TT resulted in few complications. In low-tension glaucoma the combination with TT is not sufficient to decrease the IOP. In patients with higher preoperative IOP, however, cataract surgery combined with TT could be--on the basis of a postoperative observation time of 72 months--a suitable method for lowering the IOP sufficiently. Furthermore, the use of antiglaucomatous substances was reduced by this combined procedure.

Aged↗
PubMed2002

[Complications of a voluminous congenital ciliary body cyst].

BACKGROUND: Multiple cysts of iris and ciliary body may cause many complications such as acute or chronic angle closure glaucoma. PATIENT: We present a boy with multiple congenital cysts of the iris pigment epithelium and a voluminous cyst of the unpigmented ciliary body epithelium of the right eye. This resulted in lenticular astigmatism, concomitant strabismus divergens and subsequently to anisometropia. The voluminous cyst (8 x 12 mm in diameter) was folded around the lens, reached the optic axis and resulted in displacement of the lens and contact between the iris and the corneal endothelium from 6.30 to 11. After puncture and partial resection of the cyst at the age of 8 months the boy developed a subcapsular multivesicular cataractic clouding of the temporal lens and a progredient myopia (up to - 14.0/- 2.0/0 degrees ); in contrast the left eye was hyperopic (+ 3.5/- 3.75/0 degrees ). The lens was subluxated superonasally due to congenital damage of the zonular fibres. Because development of visual acuity seemed limited by these determinants (20/200 at the right eye), cataract surgery with posterior capsulorhexis, anterior vitrectomy, and implantation of a capsular tension ring and posterior chamber intraocular lens was performed at the age of nearly five. Actually, there is an orthotropia, best corrected visual acuity in the distance of 20/32 in the right and 20/20 in the left eye; binocular vision is somewhat restricted. CONCLUSION: Usually congenital cysts are clinically not very relevant; occasionally surgical intervention is required to ensure adequate development of visual acuity.

Anisometropia↗
PubMed2002

[Do blind persons have a better sense of smell than normal sighted people?].

Functional disorders of sense organs may intensify the remaining senses. It is presumed that blind persons do not only hear better and have an intensified tactile sense but also have a stronger sense of smell. Better hearing ability was demonstrated by auditory evoked potentials. We investigated the sense of smell of blind persons by subjective tests (Sniffin' sticks: threshold, discrimination and identification) and for the first time also by objective tests (olfactory evoked potentials and trigeminal evoked potentials) and compared the results with the smelling ability of normal sighted persons by pair matching. Moreover, the investigated persons judged their performance via a questionnaire. The subjective test showed neither differences in the peripheral function nor in the central function between both groups. The amplitudes and latencies of the evoked potentials of vanillin, carbon dioxide and hydrogen sulfide were also not different. Blind persons tried unasked to identify the smell given in the discrimination test and thought themselves to be better in smelling. For the first time the smelling ability of blind people was compared with normal sighted people by objective test methods. Neither with subjective nor with objective methods differences were found.

Adult↗