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Biomedical subjects

G K Lang

Publications and source records attributed to G K Lang.

At least 73 records · Page 4Linked to original sources
PubMed1998

[Characteristics of drusen and changes in Bruch's membrane in eyes with age-related macular degeneration. Histological study].

BACKGROUND: Different types of drusen and changes in Bruch's membrane have been associated with age-related macular degeneration (AMD). METHODS: We compared 51 eyes with different stages of AMD with 40 age-matched controls using light microscopy. The degree of calcification of Bruch's membrane, fragmentation of Bruch's membrane, number of different types of drusen, and basal laminar deposit (BLD) were assessed. RESULTS: In the macular area, the presence of basal laminar deposit was most strongly associated with the presence of AMD. There was a statistically significant difference observed in the degree of calcification and fragmentation of Bruch's membrane in eyes with AMD as compared to controls. Eyes with AMD displayed significantly more soft, confluent, and large drusen as compared to controls. CONCLUSION: Calcification and fragmentation of Bruch's membrane, soft, confluent, and large drusen and BLD but not hard drusen correlated strongly with the histologic presence of AMD. Calcification and fragmentation of Bruch's membrane seem to facilitate ingrowth of choroidal neovascular membranes with consecutive development of exudative AMD.

Adult↗
PubMed1998

[Central serous chorioretinopathy. Clinical, fluorescein angiography and demographic aspects].

UNLABELLED: The purpose of this retrospective study was to analyze the demographic characteristics of central serous chorioretinopathy (CSC). METHODS: Findings of 100 consecutive subjects with CSC were evaluated. Clinical and fluorescein angiographic findings, demographic characteristics, and visual acuity were analyzed. RESULTS: The age of the patients ranged from 28 to 68 years with a mean of 43 years. No significant sex differences were found concerning age and other parameters. The highest age peak was in the group of women. The male to female ratio was 5:1. Patients with chronic CSC were significantly older (P = 0.015) than patients with the other angiographic findings. Median visual acuity was 0.5. In 40% bilateral characteristics of CSC were found. Clinical and fluorescein angiographic findings showed no significant correlation with visual acuity. CONCLUSION: The range of age distribution in CSC is wide. In older patients distinguishing CSC from age-related macular degeneration can be difficult.

Adult↗
PubMed1998

Reproducibility of measurements with a new slit lamp-mounted ocular blood flow tonograph.

PURPOSE: To assess the reliability of measurements of intraocular pressure (i.o.p.), pulse amplitude (PA), and pulsatile ocular blood flow (POBF) and the validity of measurements of IOP with a new ocular blood flow tonograph. METHODS: Intraocular pressure pulse was assessed with pneumatic tonometry. In this study, we used the OBF Labs ocular blood flow tonograph with two different pneumatic probes, a modified Langham probe and a newly developed probe. One ophthalmologist compared two machines, first with the modified Langham probe and secondly with the newly developed probe (40 volunteers). Additionally, two ophthalmologists performed measurements on different days and in different sequence (34 volunteers). Furthermore, results of IOP measurements performed with this tonograph were compared to those of Goldmann applanation tonometry (213 volunteers). RESULTS: Using the modified Langham probe, POBF and PA were associated with the machine used for the test. However, using the newly developed pobe, no relevant or statistically significant differences were found for any variables, and reliability coefficients were between 0.70 and 0.90. Linear regression analysis of the Goldmann applanation tonometer on the measurements of IOP with the tonograph showed a regression coefficient of 0.765. CONCLUSIONS: Results of measurements performed with this ocular blood flow tonograph and the newly developed probe are expected to be reliable and comparable.

Adolescent↗
PubMed1998

Diabetic retinopathy in pediatric patients with type-1 diabetes: effect of diabetes duration, prepubertal and pubertal onset of diabetes, and metabolic control.

OBJECTIVE: The objective of this study was to determine the contribution of prepubertal and pubertal onset and duration of diabetes to the development of diabetic retinopathy. STUDY DESIGN: A total of 1391 standardized fundus examinations (stereo fundus-photography) were performed in 441 children or adolescents with type-1 diabetes (median age 15.5 years, median duration of diabetes 6.3 years). RESULTS: Mild nonproliferative retinopathy was present in 72 patients (median age 19.9 years). Life table analysis revealed a median duration of diabetes until retinopathy was first diagnosed at 16.6 years (95% confidence interval: 15.3 to 18.3). Patients were stratified according to diabetes onset before or in puberty (> or = 10.4 years in girls, > or = 12.2 years in boys). In children with a prepubertal onset of diabetes, retinopathy occurred after a pubertal duration of 10.9 years compared with 15.1 years in children with onset of diabetes in puberty (p < 0.01), demonstrating the additional risk conveyed by the prepubertal years of diabetes. Long-term metabolic control had a significant influence on the prevalence of retinopathy: patients with a median HbA1c > or = 7.5% had development of retinopathy on average after 15.5 years compared with 18.3 years in patients with lower HbA1c values (p < 0.05). CONCLUSION: Both prepubertal and pubertal duration of diabetes are relevant for the development of background retinopathy. Good metabolic control should be attempted irrespective of age.

Adolescent↗
PubMed1998

[Value of optical coherence tomography in diagnosis of age-related macular degeneration. Correlation of fluorescein angiography and OCT findings].

BACKGROUND: Age-related macular degeneration (AMD) is the leading cause of blindness in industrialized countries. In this study, we used optical coherence tomography for evaluation of patients with AMD. METHODS: Optical coherence tomography imaging is analogous to ultrasound, except that reflected light instead of sound is used. The analysis of the reflected light is processed with the technique of low-coherence interferometry. In this study, 33 patients with different stages of AMD were examined with optical coherence tomography. The classification of AMD was according to the guidelines as proposed by the "International ARM Epidemiological Study group". RESULTS: With this method we were able to identify drusen, alteration of the retinal pigment epithelium, and secondary retinal changes. Other structures such as basal laminar (linear) deposits could not be identified with this method. Choroidal neovascularization was evident in the tomogram. Classic choroidal neovascular membranes presented with well-defined boundaries on optical coherence tomography and occult choroidal neovascular membranes had a less delineable structure with optical coherence tomography. CONCLUSION: Optical coherence tomography cannot replace conventional diagnostic techniques. This method provides no additional information in patients with non-exsudative AMD. In patients with choroidal neovascular membranes secondary to AMD optical coherence tomography may be able to characterize the relation of the membrane to the retinal pigment epithelium and imaging may be possible through hemorrhage. The interpretation of the optical coherence tomogram needs further studies including clinicopathologic correlation.

Aged↗
PubMed1998

[Intracanalicular trabeculostomy--a new approach to glaucoma surgery].

BACKGROUND: A new "ab externo" technique for glaucoma trabecular surgery creating multiple perforations of the trabeculum to improve outflow facility was tested. MATERIAL AND METHOD: In order to perform a draining canal to the anterior chamber, a quartz fiber (phi: 300 microns) with a side-firing tip, coupled to an Er:YAG laser (2.94 microns), was inserted into Schlemm's canal of an enucleated human eye. RESULTS: Eight pulses of 8 mJ each were sufficient to perforate the trabecular meshwork. Histologic analysis showed a rippled canal with 50 microns average diameter and a surrounding necrosis zone of 15-35 microns. CONCLUSIONS: The Er:YAG laser trabeculostomy, in conjunction with special fibers, shows promise as a new "ab externo" technique for minimally invasive therapy of open angle glaucoma.

Endoscopes↗
PubMed1998

[Ocular changes in primary hematologic diseases].

Ocular manifestations can be the presenting symptom of hematological diseases. Ocular changes can be found in up to 90% of the patients depending on the underlying disease. Most patients with ocular manifestations however are asymptomatic. Hematological disorders can manifest in all structures and adnexa of the eye. The most common manifestations are conjunctival pallor and hemorrhages, intraretinal hemorrhages and cotton wool spots. Retinal infiltrates, manifestations in the lids, anterior segment, optic nerve, orbit and adnexa are rare. Different ocular manifestations in anemia, leukemia, malignant Non-Hodgkin lymphoma, Hodgkin's disease, chronic myeloproliferative diseases, plasmocytoma, myelodysplastic syndromes, coagulopathies, and reticulo-histiocytic diseases are described. Not only the underlying disease but also chemotherapy, bone marrow transplantation can lead to ocular complications.

Eye Diseases↗
PubMed1998

Retinal pigment epithelial changes associated with systemic corticosteroid treatment: report of cases and review of the literature.

PURPOSE: The aim of our study was to describe two different manifestations of retinal pigment epithelial changes associated with systemic corticosteroid treatment. METHODS: We report 4 patients who developed maculopathy during treatment with systemic corticosteroids. Additionally, the literature was reviewed for similar cases. RESULTS: Two patients showed diffuse retinal pigment epitheliopathy. Two patients developed central serous chorioretinopathy with localized changes in the retinal pigment epithelium. A review of the literature revealed 51 patients with similar changes during treatment with corticosteroids. CONCLUSION: These 4 patients provide further evidence that systemic treatment with corticosteroids may cause central serous chorioretinopathy or diffuse retinal pigment epitheliopathy. Ophthalmologic examination is recommended on a regular basis for patients treated with systemic corticosteroids.

Adult↗
PubMed1998

Influence of special-effect contact lenses (Crazy Lenses) on visual function.

PURPOSE: Special-effect contact lenses (opaque, tinted soft contact lenses that incorporate decorative images such as "cateyes," stars, or hearts to alter eye color and structure) have become increasingly popular. The purpose of this study was to investigate whether such lenses impair visual function. METHODS: A clear soft contact lens and a special-effect soft contact lens (Crazy lens,) were fit in changing sequence in nine healthy subjects. The parameters studied included: visual acuity, contrast sensitivity (with and without glare), visual field, and mesopic vision (with and without glare). RESULTS: The following parameters displayed a statistically significant difference (P < 0.05). Visual acuity was decreased to 0.9 +/- 0.23 in the Crazy lens group as compared with 1.2 +/- 0.13 in the clear lens group. Goldmann visual field displayed a significant constriction of the isopters: III/4, I/4, and I/3. Mesopic vision without glare was reduced from 1:2.5 to 1:7.4. Contrast sensitivity was significantly reduced in a photopic condition with and without glare and in a scotopic condition without glare. Furthermore, the special-effect lenses were associated with a decrease in lens wearing comfort. CONCLUSIONS: Special-effect contact lenses were associated with a reduction of many visual functions, including visual acuity and contrast sensitivity. For some wearers this may interfere with activities where excellent vision is crucial, such as driving a car.

Adult↗
PubMed1997

[Central serous chorioretinopathy in systemic therapy with corticosteroids].

PURPOSE: To describe retinal pigment epithelial changes associated with systemic corticosteroid treatment. METHODS: We report on five patients who developed maculopathy during treatment with systemic corticosteroids. A thorough ophthalmologic examination including perimetry, fundus photography, and fluorescein angiography was performed. RESULTS: Three patients displayed focal and two patients showed diffuse retinal pigment epithelial changes comparable to the acute and chronic form of central serous chorioretinopathy, respectively. Four of five patients had a complete visual recovery after decrease or cessation of treatment with corticosteroids. CONCLUSION: These five patients provide further evidence that systemic treatment with corticosteroids may damage the posterior blood-retinal barrier, leading to central serous chorioretinopathy. Visual acuity may increase after reduction of the dosage or cessation of treatment with corticosteroids. Patients on systemic corticosteroid treatment should be informed about possible symptoms of central serous chorioretinopathy in order to prevent irreversible visual loss.

Adrenal Cortex Hormones↗
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↗
PubMed1997

[Idiopathic polypoid choroid vasculopathy].

BACKGROUND: The idiopathic polypoidal choroidal vasculopathy, also known as "posterior uveal bleeding syndrome" or "multiple recurrent serosanguineous retinal pigment epithelial detachments in black women" is a rare disease entity. A clincopathologic correlation of a patient with this disease is presented. CASE REPORT: A 47-year-old black woman was evaluated for a decrease of visual acuity in her right eye which had occurred over the last 3 months. Ophthalmic examination of her right eye revealed sub-RPE hemorrhage associated with a reddish-orange subretinal vascular-like lesion. In addition, both eyes displayed a few choroidal vascular-like bulbous structures in the superior temporal peripapillary region. The patient developed an extensive choroidal hemorrhage that led eventually to the enucleation of the eye. CONCLUSION: Choroidal neovascular membranes (CNV) secondary to idiopathic polypoidal choroidal vasculopathy differs in many aspects from other entities associated with CNV including clinical and fluorescein angiographic features, clinical course, and prognosis.

Bruch Membrane↗
PubMed1997

[Reparative giant cell granuloma with orbital involvement].

A 54-year-old woman was evaluated for a left orbital mass that had been present for one year. Examination showed mild superolateral displacement of the normal left eye and a firm medical orbital mass. A complete resection of the lesion was accomplished via a combined neurosurgical, otolaryngologic and ophthalmologic superior orbital approach. Histologic features of the mass were consistent with giant-cell (reparative) granuloma. However, it has to be pointed out that fibroosseous lesions with giant-cells display similar histologic features and require clinicopathologic correlation including radiographic studies for final diagnosis.

Diagnosis, Differential↗
PubMed1997

[Histological characterization and classification of surgically excised choroid neovascular membranes].

PURPOSE: This study was undertaken in order to histologically characterize surgically-excised choroidal neovascular membranes and to correlate theses histologic findings with the fundus and fluorescein angiographic appearance. MATERIAL AND METHODS: Surgically-excised subfoveal choroidal neovascular membranes submitted in the time period from November 1994 to July 1996 were included in this study. The membranes were processed and evaluated by light and transmission electron microscopy. Some membranes were oriented by the surgeon and marked on their inner surface with India ink and the configurations of these membranes were recorded and correlated with the fundus and fluorescein angiographic features. RESULTS: Sixty-two choroidal neovascular membranes were available for this study. In 74% age-related macular degeneration was the underlying disease. Retinal pigment epithelium and endothelial lined vascular channels were present in over 87.5% of cases. Basal laminar (linear) deposit was only present in membranes excised from patients with age-related macular degeneration. In six cases with Gass Type II choroidal neovascular membranes the histologic-clinical-fluorescein angiographic correlation showed well-defined (classic) neovascular membranes according to the criteria of the Macular Photocoagulation Study. Two membranes were not surrounded by retinal pigment epithelium and were classified as Type IIa membranes. Four membranes were surrounded by retinal pigment epithelium and classified as Type IIb membranes. CONCLUSIONS: Choroidal neovascular membranes represent a stereotypic, non-specific wound repair response to a specific stimulus. Retinal pigment epithelium may proliferate around and attempt to wall off choroidal neovascular membranes. We propose a new classification of surgically-excised choroidal neovascular membranes as Types I, IIa, and IIb.

Adult↗
PubMed1997

[Bilateral adult periocular xanthogranuloma].

PATIENT: A 62-year-old woman was evaluated for a bilateral subconjunctival mass that had been present for 6 months. With magnetic resonance imaging the lesion could not be delineated form the lacrimal glands. A biopsy was performed and histologic examination exhibited a xanthogranulomatous lesion with multiple giant-cells of the Touton type. The differential diagnosis of the adult xanthogranuloma is Erdheim-Chester disease, necrobiotic granuloma, xanthoma, Langerhans histiocytosis, and Rosai-Dorfman syndrome. CONCLUSION: Hyperlipemia should be excluded, in addition, in the presence of necrobiosis, paraproteinemia.

Conjunctiva↗
PubMed1997

[Results after combined phacoemulsification and trabeculectomy by scleral tunnel incision and goniotrepanation alone].

PURPOSE: We retrospectively evaluated the results of combined phacoemulsification and trabeculectomy through scleral tunnel incision in comparison with those of goniotrephination alone. PATIENTS AND METHODS: 27 eyes of 20 patients (78.3 +/- 7.45 years) underwent a combined trabeculectomy and phacoemulsification with IOL-implantation (PT-group). The trabeculectomy was performed by excision of 2 mm middle part of the lower tunnel lip. In comparison with the TP-group 29 eyes of 28 patients (69.3 +/- 8.1 years) underwent a goniotrephination (Fronimopoulos), (G-group). The median of follow up was 8 weeks. RESULTS: In both groups a significant reduction of the IOP was achieved; in the PT-group the IOP was reduced from 31.0 +/- 5.42 to 15.0 +/- 4.5 mm Hg, in the G-group from 31.4 +/- 6.3 to 11.6 +/- 4.12 mmHg. In the PT-group the visual acuity increased significantly from 0.25 +/- 0.14 to 0.37 +/- 0.27 and decreased significantly from 0.46 +/- 0.28 to 0.32 +/- 0.25 in the G-group. 3 patients (= 11%) needed topical medication in the PT-group and 6 (= 24%) in the G-group. Four patients (= 15%) of the PT-group underwent a secondary surgery and 7 (= 24%) of the G-group. CONCLUSIONS: The combined phacoemulsification and trabeculectomy is a successful method of IOP control and visual rehabilitation. Due to the decrease of visual acuity and a higher frequency of secondary surgery after goniotrephination alone the combined procedure should be preferred even in presence of a moderately visual acuity reducing cataract.

Aged↗