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Biomedical subjects

H J Buchwald

Publications and source records attributed to H J Buchwald.

10 recordsLinked to original sources
PubMed2001

[Prospective randomized comparative study of frequency doubling perimetry vs standard automated perimetry in patients with glaucoma].

AIM: To compare frequency doubling perimetry (FDP) versus standard automated perimetry in glaucoma. To evaluate the reproducibility of both methods. PATIENTS AND METHODS: All the patients were tested (full threshold test) twice with both FDP (N-30) and Humphrey Field Analyzer II model 750 (HFA) (30-2 procedures) in random sequence, within one day. The parameters mean deviation (MD), pattern standard deviation (PSD) and measured thresholds per quadrant and center areas were evaluated for FDP/HFA comparison in 45 glaucoma patients. The same parameters were used for testing the reproducibility of FDP (n = 46) and HFA (N = 39). Additionally, the center and each quadrant area were checked for any deviation in the total deviation probability plots. For statistical analysis Kappa coefficients and Bland/Altman plots were used. RESULTS: An average MD (FDP vs HFA) of -7.3 +/- 5.8 dB vs -8.9 +/- 7.6 dB and PSD of 6.9 +/- 2.4 dB vs 6.5 +/- 3.6 dB were found. Kappa coefficients denote marginal accordance (kappa: 0.11-0.38) for area deviations. In a total of 225 areas HFA detected 191 deviations and FDP 165. HFA measured more negative deviation compared with FDP in the case of MD < -15 dB. The reproducibility was 0.98 (MD) and 0.92 (PSD) for FDP and 0.98 (MD) and 0.95 (PSD) for HFA (95% confidence interval). CONCLUSIONS: There was great conformity between FDP and HFA in glaucoma patients. HFA detected more deviations in the total deviation probability plots than FDP. There was a high reproducibility of both methods. FDP is an appropriate tool for detecting visual field loss in glaucoma patients.

Adult↗
PubMed2001

[Optic nerve evulsion: Metaanalysis].

BACKGROUND: Evulsion of the optic nerve is a rare form of traumatic optic neuropathy. It is a rupture of the optic nerve at the disc without damage of its sheaths occurring in association with a blunt skull trauma or a blunt bulbar trauma. MATERIAL AND METHODS: We searched the literature using Medline database for all articles with evulsion of the optic nerve. The bibliographies of the papers found therein were used to get a complete review. The data were analyzed with special regard to age, sex, mechanism of injury, and (if available) defects of visual field. RESULTS: Sixty-three patients with a mean age of 22 years (range 4 to 60 years) were included in the study. In 22 patients (35 %) a partial and in 41 patients (65 %) a complete evulsion was present. In 31 patients (49 %) the cause was a small blunt object or finger that stroke the eye or entered the orbita. In 19 patients (30 %) a severe blunt skull trauma had occurred. The analysis of visual fields in eyes with partial evulsion of the optic nerve revealed a defect in the superior visual field in 6 of 12 patients and a defect in the inferonasal visual field in 3 of 12 patients. PATHOGENESIS: Our review suggests that the most common mechanism of injury is a severe rotation of the eye leading to rupture of the optic nerve fibers and an anterior displacement of the bulbus, possibly with deformation of the posterior eye walls.

Adolescent↗
PubMed1999

[Ultrasound biomicroscopy in iris lesions].

INTRODUCTION: It is difficult to classify lesions of the iris, especially when they are posterior or in the iridociliary angle of the eye. METHOD: We used an ultrasound biomicroscope (Humphrey, Zeiss, Oberkochen, Germany) with a high-frequency sound head (30 and 50 Hz). This study included all patients with unspecified iris processes who were examined at the University Eye Clinic and Hospital of Ulm between September 1996 and February 1997. Fifteen patients, aged between 9 to 82 years (average age = 48.9 years), were prospectively evaluated. RESULTS: A cyst of the iris or ciliary body causing a tumor of the iris was found in six cases (40%). Seven patients (47%) showed a solid tumor of the iris and two patients (13%) a solid tumor of the ciliary body. CONCLUSION: The ultrasound biomicroscope can be used to assess lesions of the iris caused by a cyst or a solid tumor. The increasing size and depth expansion of a solid tumor may be helpful for differentiating between a malignant or benign process. Up to now it has not been possible to use the ultrasonic reflectivity of the tumor to decide if it is malignant.

Adolescent↗
PubMed1999

[Contusion of the optic nerve after minor blunt ocular trauma: case report and literature review].

INTRODUCTION: Isolated trauma of the optic nerve usually occurs in association with blunt skull trauma involving fractures of the skull and optic canal, but rarely occurs from blunt ocular trauma. CASE REPORT: A 7-year old boy fell and struck his left eye against a toy antenna. The initial examination revealed a visual acuity of 0.2 and slight edema of the optic nerve head. Perimetry revealed a defect in the superior and nasal visual fields. CT and MRI scans of the orbit were normal. Nine months after the injury, vision had improved to 1.0. On examination, optic nerve atrophy had developed and perimetry continued to display a defect in the superior visual fields. DISCUSSION: The mechanism of optic nerve damage secondary to trauma can be classified as primary or secondary. Primary damage occurs as a result of external forces at the moment of trauma, e.g., rupture of nerve fibers or of capillary vessels. Secondary damage may not be present initially, but may occur later on and results from compromised blood supply to the optic nerve, e.g., following edema or angiospasm. In our patient, it is not clear whether the damage was primary or secondary. CONCLUSION: Damage to the optic nerve can be caused by blunt skull trauma and, rarely, also by blunt ocular trauma. This fact is of importance when considering legal and reimbursement issues.

Child↗
PubMed1997

[Idiopathic conjunctival lymphangiectasia].

PATIENT: A 41-year-old male was evaluated for multiple yellowish cysts on the temporal bulbar conjunctiva of his right eye. These cysts have spontaneously developed over a period of one week, have been punctuated, and recurred one week later in an even greater number. The patient's ophthalmologic and medical history were normal. Complete excision of the largest cysts and marsupialization of the smaller cysts were performed. Histologic features of the excised cysts were consistent with lymphangiectasia and displayed dilated lymphatic channels. CONCLUSION: Conjunctival lymphangiectasia is a benign condition of unknown etiology. It has been observed with many underlying diseases as well as spontaneously and the dilated lymphatic channels can secondarily become hemorrhagic (Hemorrhagic lymphangiectasia of the conjunctiva). Simple excision and/or marsupialization are therapeutic options.

Adult↗
PubMed1991

[Ab-interno sclerostomy with the excimer laser via a quartz fiber in albino rabbits].

After attempting to induce experimental glaucoma in 20 albino rabbits by topical administration of 0.1% dexamethasone, ab-interno sclerostomy with an excimer laser at 308 nm via a quartz fiber was performed in one eye of each animal. Preoperatively, the sclera was stained with a UV-absorbing drug (sulfisomidine) in 10 rabbits; to shield the lens from scattered radiation, another UV absorber (fluorescein) was injected additionally into the anterior chamber. The other 10 rabbits were operated on without pretreatment. A full-thickness sclerostomy was performed in all animals. Most of the eyes upon operated showed minimal inflammation in the first few postoperative days. The intraocular pressure in the operated eyes was reduced compared to the fellow eye for about 3 months. Histology showed a 50-microns broad, smooth, thermally damaged zone at the edges of the sclerostomy. Clinical and histological investigation showed no evidence of UV-induced damage on the lens or retina in either group. Application of the UV absorber led to a significant decrease in the number of pulses required to perforate the sclera, but had no influence on the clinical history.

Animals↗
PubMed1990

[Fluorescence behavior of the cornea with 193 nm excimer laser irradiation].

Fluorescence spectra of human, bovine and porcine corneas were measured under 193 nm excimer laser irradiation. Secondary radiation occurs in the mutagenic range between 260 and 290 nm. In situ measurements via a quartz fiber introduced into the eye to the lens surface showed that secondary radiation in the cataractogenic range between 295 and 320 nm is transmitted by the cornea and reaches the lens. The potential adverse effects of this secondary radiation should be considered when applying 193 nm excimer laser radiation to the cornea.

Animals↗
PubMed1989

[In vitro studies of refractive corneal surgery using the excimer laser with quartz fiber].

With the application of different approved drugs, UV absorption of the cornea at 308 nm could be increased by more than three orders of magnitude, which provided effective shielding of intraocular structures against 308 nm excimer laser radiation. The width of the thermal damage zones at the edges of 308 nm excimer laser excisions was reduced to a few micrometers by our treatment. The ablation threshold was reduced by this treatment and the ablation rates were increased by a factor of three to five. In principle, these results offer the possibility of performing refractive corneal surgery with excimer lasers at 308 nm via quartz fibers.

Animals↗