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Biomedical subjects

F W Fitzke

Publications and source records attributed to F W Fitzke.

At least 19 recordsLinked to original sources
PubMed1999

[Serous central chorioretinopathy. Acute autofluorescence of the pigment epithelium of the eye].

PURPOSE: The lack of histopathological material has placed limitations on our knowledge on lipofuscin in central serous chorioretinopathy (CSCR). This study was designed to document the pathological changes of the retinal pigment epithelium (RPE) in CSCR using in vivo recording of fundus autofluorescence. METHODS: Fundus autofluorescence was documented in 62 eyes of 44 subjects with CSCR using a laser scanning ophthalmoscope (Zeiss, Oberkochen; excitation wavelength: 488 nm, barrier filter at 521 nm). Images were compared to the respective fundus appearance and fluorescein angiograms. RESULTS: Neurososensory retinal detachments showed diffuse increased autofluorescence corresponding to the detached area. Long-standing lesions showed very irregular autofluorescence with regions greater and less than the background levels of autofluorescence. CONCLUSION: Focal accumulation of autofluorescent material occurs at the level of the RPE in patients with CSCR, relating to variation in metabolic activity of the RPE. This technique may be useful in selecting patients for laser photocoagulation.

Adult↗
PubMed1999

Distribution of pigment epithelium autofluorescence in retinal disease state recorded in vivo and its change over time.

BACKGROUND: Recently a technique of imaging the retinal pigment epithelium (RPE) has been developed that takes advantages of its intrinsic fluorescence derived from lipofuscin. The purpose of this study was to document the distribution of fundus autofluorescence in patients with various retinal diseases and its change over time. METHODS: The intensity and spatial distribution of fundus autofluorescence was documented in 318 eyes from 159 patients with various retinal diseases using a confocal Laser Scanning Ophthalmoscope. Thirty patients with macular dystrophies and 30 with age-related macular disease underwent serial examinations over a period of 1-3 years in order to monitor the changes over time of fundus autofluorescence. RESULTS: Absent autofluorescence corresponded well spatially with outer retinal atrophy in eyes with retinitis pigmentosa and rod-cone dystrophy. Abnormally high background autofluorescence was seen in the macular region in some patients with dominant and recessive retinitis pigmentosa and rod-cone dystrophies. In areas of macular edema fundus autofluorescence was abnormal. Fundus autofluorescence showed changes over time in most of the eyes with retinal diseases studied. CONCLUSION: Fundus autofluorescence allows documentation of areas of photoreceptor cell loss in eyes with retinitis pigmentosa and rod-cone dystrophies. If abnormal high background autofluorescence in the surviving areas occurs only in some patients with retinitis pigmentosa, the technique may serve to distinguish the regional from the diffuse type of disease. Over time, fundus autofluorescence may demonstrate change or may remain stable.

Adolescent↗
PubMed1998

Clinical features in affected individuals from 21 pedigrees with dominant optic atrophy.

OBJECTIVE: To assess phenotypic variation of affected individuals from British families with autosomal dominant optic atrophy. DESIGN: Eighty-seven patients from 21 families showing evidence of linkage to chromosome 3q were identified via the Genetic Clinic of Moorfields Eye Hospital, London, England. Genetic linkage analysis was carried out with markers from chromosome 3q28-qter. Patients underwent clinical examination and psychophysical and electrophysiological testing. RESULTS: Best-corrected visual acuity ranged from 20/20 (6/6 m) to light perception. Although visual acuity was not significantly worse in older patients in the group (chi2=3.20, df=4, P>.50), it did deteriorate with age in one third of the families. Subtle or temporal pallor of the optic disc occurred in 96 (55%) of 174 eyes and total atrophy in 76 (44%). Tritanopia was found in 6 (7.5%) of 80 patients; 65 (81.2%) had a mixed color deficit. A cecocentral scotoma was found in the vast majority. Peripheral motion detection threshold was elevated in areas of visual field with raised mean surround sensitivity but not elsewhere. Pattern visual evoked potentials were of reduced amplitude and delayed. Pattern electroretinograms showed a reduced N95 component in keeping with primary ganglion cell dysfunction. CONCLUSIONS: There is wide intrafamilial and interfamilial phenotypic variation in autosomal dominant optic atrophy, with visual function in some, but not all, families deteriorating with age. There is evidence of degeneration of the ganglion cell layer predominantly from central retina, but this is not the exclusive result of either parvocellular or magnocellular cell loss.

Adolescent↗
PubMed1998

[Studies of the distribution of lipofuscin in the retinal pigment epithelium using high-resolution TV laser scanning ophthalmoscopy].

BACKGROUND: The fundus autofluorescence imaging technique has been modified allowing improved image resolution (768 x 572 pixel). We present results of fundus autofluorescence studies using this technique. MATERIALS AND METHODS: Fundus autofluorescence was studied in 286 eyes of 143 patients with retinitis pigmentosa, macular dystrophies and age-related macular degeneration using a confocal laser scanning ophthalmoscope prototype (Zeiss, Oberkochen; excitation wavelength: 488 nm, cut-off filter at 521 nm). RESULTS: The spatial distribution of autofluorescence was different in all diseased eyes investigated compared to the normal pattern of fundus autofluorescence. Each disorder showed a specific fundus autofluorescence appearance. CONCLUSIONS: The advanced technique of imaging fundus autofluorescence allows detailed studies of the lipofuscin distribution. In vivo analysis of the dynamics of accumulation and degradation of lipofuscin in eyes with tapeto-retinal dystrophies and age-related macular disease may contribute to elucidation of the pathogenesis of these disorders.

Adolescent↗
PubMed1998

Abnormal motion displacement thresholds are associated with fine scale luminance sensitivity loss in glaucoma.

This study tests the hypothesis that abnormal motion displacement thresholds coexist with scotomas on a finer spatial scale than is measurable by conventional Humphrey perimetry. Eighteen patients with primary open angle glaucoma in one eye, and 18 age matched normal controls underwent motion displacement threshold testing and high spatial resolution perimetry. The motion displacement thresholds were significantly elevated in the glaucoma eyes, in 73% this exceeded normal limits. Ten glaucoma eyes had normal Humphrey 24-2 field nearest the motion test site: of these seven had abnormally elevated motion displacement thresholds and six had fine scale threshold depressions detected with high spatial resolution perimetry. This result suggests that glaucomatous elevations of motion displacement threshold may be present in areas of normal Humphrey 24-2 field, and this may coexist with measurable scotomas beyond the resolution of conventional Humphrey perimetry in some, but not all patients.

Adult↗
PubMed1998

Magnification characteristics of fundus imaging systems.

OBJECTIVE: To compare the magnification properties of 11 different fundus cameras (including 1 stereo fundus camera), a Rodenstock (infrared) scanning laser ophthalmoscope (SLO), the Heidelberg Laser Tomographic Scanner (LTS), and the Heidelberg Retina Tomograph (HRT). DESIGN: A cross-sectional study of the relationship between the true size of a fundus feature and its photographic-computer image in 14 different fundus imaging devices. This relationship was evaluated for each instrument using a model eye adjusted for axial ametropia between +11 diopter (D) and -14 D. To simulate refractive ametropia, the "crystalline lens" was removed to render the model eye aphakic, and the axial length was adjusted to give aphakic ametropia from emmetropia to +20 D. MAIN OUTCOME MEASURES: A correction factor (p) was calculated for each instrument, which can be used in calculations for determining true retinal size. RESULTS: The following were found to be of telecentric construction, Zeiss Oberkochen (WS240 Heidelberg), Zeiss Oberkochen (UK), Zeiss Oberkochen (Cologne), Nikon NF505, Kowa RCXV, SLO prototype (UK), LTS, and the HRT, and each exhibited a constant relationship between p and degree of ametropia of the model eye. The Canon CF6OU, Canon CF6OS, Canon CR4-45NM, Nidek 3-DX, Olympus GRCW, and Carl Zeiss Jena Retinophot were found not to be telecentric and exhibited a linear relationship between p and degree of ametropia of the model eye. For all instruments, p remained unchanged for axial and refractive ametropias of the same degree. CONCLUSIONS: The study has shown that not all fundus imaging systems are telecentric, so the use of a single magnification correction value may not be appropriate. These findings have important implications for the way in which true retinal size calculations are performed. Examples are given to show how the tabulated values of correction factors can be used for both telecentric and nontelecentric cameras in image size calculations.

Fundus Oculi↗
PubMed1998

[Fundus autofluorescence in patients with hereditary macular dystrophies, malattia leventinese, familial dominant and aged-related drusen].

PURPOSE: The lack of histopathological material has placed limitation on our knowledge on the composition of focal deposits in eyes with macular dystrophies, malattia leventinese, dominant drusen and age related macular degeneration. This study was designed to study the composition of focal deposits in these eyes by documenting fundus autofluorescence in vivo. METHODS: Fundus autofluorescence was documented in 343 eyes of 199 subjects with macular dystrophies, malattia leventinese, dominant drusen and age-related macular degeneration using a laser scanning ophthalmoscope (Zeiss, Oberkochen; excitation wavelength: 488 nm, barrier filter at 521 nm). RESULTS: Autofluorescence of focal deposits was increased in eyes with macular dystrophies. In eyes with malattia leventinese and dominant drusen autofluorescence intensity of focal deposits showed a wide spectrum. In contrast, autofluorescence of age-related drusen was within normal limits. Background autofluorescence intensity was increased in eyes with macular dystrophies and within normal limits in eyes with malattia leventinese, dominant drusen and age-related drusen. CONCLUSION: The technique of in-vivo recording of fundus autofluorescence allows the differential diagnosis between macular dystrophies/malattia leventinese, dominant drusen/age related drusen when otherwise not possible.

Adult↗
PubMed1998

In vivo morphometry of the lamina cribrosa and its relation to visual field loss in glaucoma.

PURPOSE: The lamina cribrosa has been proposed as a site of origin of the optic nerve damage in glaucoma. The purpose of this study was to investigate, in vivo, the clinical features of the lamina cribrosa pores of glaucomatous patients and to relate their morphometric characteristics to the extent of their visual field loss. METHODS: Images of the internal lamina cribrosa surface of 60 glaucomatous patients and 15 normal subjects were acquired, in vivo, using a scanning laser ophthalmoscope (SLO). A purposely developed technique of image processing was employed to objectively evaluate pore morphometry, with particular regard to their geometrical characteristics (circularity and elongation). Visual function was assessed by automated perimetry (Humphrey Field Analyser). RESULTS: Normal subjects showed approximately round lamina pores. In glaucomatous patients, pores become more elongated and less circular with increasing field loss (p = 0.009 and p < 0.001, respectively). CONCLUSIONS: Scanning laser ophthalmoscopy and a new technique of image processing were employed, for the first time, to the investigation in vivo of the lamina cribrosa of glaucomatous patients, in relation to the extent of visual field loss. The results indicated differences in the lamina cribrosa pore morphometry associated with increasing severity of the disease. These changes may represent the result of compressing and shearing forces applied to the laminar plates.

Adult↗
PubMed1998

Treatment of pigment epithelial detachments due to age-related macular degeneration with intra-ocular C3F8 injection.

PURPOSE: To flatten pigment epithelial detachments (PED) due to age-related macular degeneration in an attempt to visualize the underlying choroidal neovascularization by fluorescein angiography (FA) and reveal a treatment target. METHODS: Nine patients with PED received intravitreal gas injections via the pars plana and postured face down. Fluorescein angiograms were obtained before and after gas injection. In two patients, retinal scotopic sensitivity was also measured. RESULTS: Eight patients demonstrated change in the shape and size of the PED following gas injection. Four patients showed a better delineation of underlying structures on FA. Three patients had focal laser treatment to the newly visible choroidal neovascular complex, but this was successful in only one patient with flattening of the PED. CONCLUSION: Pigment epithelial detachments can be modified by intravitreal gas injection in some patients, but this treatment did not have a major impact on overall outcome or management.

Aged↗
PubMed1998

Phenotype of a British North Carolina macular dystrophy family linked to chromosome 6q.

AIMS: To document the phenotype of an autosomal dominant macular dystrophy diagnosed as having North Carolina macular dystrophy (NCMD) in this British family, and to verify that the disease locus corresponds with that of MCDR1 on chromosome 6q. METHODS: 37 family members were examined and the phenotype characterised. DNA samples from the affected members, 19 unaffected and five spouses, were used to perform linkage analysis with six microsatellite marker loci situated within the MCDR1 region of chromosome 6q. RESULTS: Every affected family member had lesions characteristic of NCMD, which developed early in life and usually remain stable thereafter. Although fundus changes are evident in the periphery, all tests revealed that functional loss is restricted to the macula. Some patients with large macular lesions had good visual acuity with fixation at the edge of the lesion at 5 degrees eccentricity. Significant linkage to the MCDR1 locus on chromosome 6q was obtained with three marker loci, with a maximum lod score of 5.9 (q = 0.00) obtained with D6S249. CONCLUSION: This family has the typical phenotype NCMD, and the causative gene was linked to the disease locus (MCDR1) on chromosome 6q. Early onset and localisation of the disease to the central macula allow specialisation of eccentric retina in some eyes with resultant good visual acuity.

Adolescent↗
PubMed1998

Simulating binocular visual field status in glaucoma.

AIMS: To simulate the central binocular visual field using results from merged left and right monocular Humphrey fields. To assess the agreement between the simulation and the binocular Humphrey Esterman visual field test (EVFT). METHOD: 59 consecutive patients with bilateral glaucoma each recorded Humphrey 24-2 fields for both eyes and binocular EVFT on the same visit. EVFT results were used to identify patients exhibiting at least one defect (< 10 dB) within the central 20 degrees of the binocular field. This criterion is relevant to a patient's legal fitness to drive in the UK. Individual sensitivity values from monocular fields are merged to generate a simulated central binocular field. Results are displayed as a grey scale and as symbols representing defects at the < 10 dB level. Agreement between patients failing the criterion using the simulation and the EVFT was evaluated. RESULTS: Substantial agreement was observed between the methods in classifying patients with at least one defect (< 10 dB) within the central binocular field (kappa 0.81; SE 0.09). Patients failing this criterion using the EVFT results were identified by the binocular simulation with high levels of sensitivity (100%) and specificity (86%). CONCLUSIONS: Excellent agreement exists between the simulated binocular results and EVFT in classifying glaucomatous patients with central binocular defects. A rapid estimate of a patient's central binocular field and visual functional capacity can be ascertained without extra perimetric examination.

Adult↗
PubMed1998

Fundus autofluorescence in patients with macular holes imaged with a laser scanning ophthalmoscope.

AIM: To demonstrate the usefulness of a recently developed technique of imaging fundus autofluorescence and to compare it with the results of fluorescein angiography in the diagnosis and staging of macular holes. METHODS: The intensity and distribution of fundus autofluorescence was studied in 51 patients with idiopathic macular holes and pseudoholes using a confocal laser scanning ophthalmoscope (cLSO) and the images were compared with those obtained by fundus fluorescein angiography. RESULTS: Autofluorescence imaging demonstrated bright fluorescence of macular holes with appearance similar to that obtained by fluorescein angiography. In contrast macular pseuodoholes showed no such autofluorescence. The attached operculum in stage 2 macular holes and the preretinal operculum in stage 3 macular holes showed focal decreased autofluorescence. The associated retinal elevation and the cuff of subretinal fluid were less fluorescent compared with the background autofluorescence of the normal fellow eyes. Following successful surgical treatment the autofluorescence of the macular holes was no longer visible. CONCLUSION: Autofluorescence imaging with the cLSO makes the assessment of macular holes possible with an accuracy comparable with that of fluorescein angiography. Being non-invasive and rapid, autofluorescence imaging may become a useful alternative to fluorescein angiography in the assessment and the differential diagnosis of full thickness macular holes.

Aged↗
PubMed1998

Measurement of optic disc size: equivalence of methods to correct for ocular magnification.

AIMS: To compare methods available to correct the magnification of images that result from the optics of the eye and identify errors, and source of error, of the methods. METHODS: 11 methods were applied to ocular biometry data from three independent cohorts. Each method was compared with the method of Bennett, which uses most biometric data. The difference between each method and Bennett's is the "error" of the method. The relation between the error and axial length, ametropia, and keratometry was explored by linear regression analysis. RESULTS: Methods using axial length had the lowest mean (+0.5 to +2.6%) and standard deviation (0.6 to 1.2%) of errors. Of methods using keratometry and ametropia only, the lowest mean (-1.4% to +4.4%) and standard deviation (2.9 to 4.3%) of errors was found for a new method described in this paper, and that used by the Heidelberg retina tomograph (HRT). The highest mean error (+2.2 to +7.1%) was found for Littmann's method. Littmann's correction was larger than the HRT's by 3.5 to 3.7%. The mean difference between the new and HRT methods and the "abbreviated axial length" method of Bennett is -1.3 to +2.0%. The error of the "keratometry and ametropia" methods is related to axial length. CONCLUSIONS: Methods using axial length are most accurate. The abbreviated axial length method of Bennett differs little from more detailed calculations and is appreciably more accurate than methods using keratometry and ametropia alone. If axial length is unknown, the new and the HRT methods give results closest to the abbreviated axial length method.

Aged↗
PubMed1998

[Dynamics of accumulation and degradation of lipofuscin in retinal pigment epithelium in senile macular degeneration].

BACKGROUND: It is thought that lipofuscin plays a central role in the pathogenesis of age-related macular degeneration (AMD). The lack of histopathological material has been a severe limitation in our knowledge on lipofuscin in this disease. A new technique has been developed that allows in vivo imaging of fundus autofluorescence derived from lipofuscin in the retinal pigment epithelium (RPE) using a confocal Laser Scanning Ophthalmoscope (LSO). We studied the dynamics of lipofuscin accumulation and degradation in patients with AMD. MATERIALS AND METHODS: Serial examinations of the spatial distribution of fundus autofluorescence were performed in 148 eyes of 74 patients with AMD using a LSO over a period of 1-3.5 years. RESULTS: Fundus autofluorescence changed over time in almost all eyes studied. Areas of increased autofluorescence occurred progressively during follow up in eyes with drusen and hyperpigmentation. The size of pathologic autofluorescence increased over time in almost all eyes with geographic atrophy, subretinal neovascularisations and disciform scars. Irregular autofluorescence was seen over most subretinal neovascularisations. Autofluorescence intensity decreased in old subretinal neovascularisations and disciform scars over time. CONCLUSIONS: Changes of the distribution of autofluorescence occur in eyes with AMD over time. Fundus autofluorescence imaging allows in vivo analysis of the dynamics of accumulation and degradation of lipofuscin in the RPE in eyes with AMD and documentation of metabolic activity of the RPE.

Aged↗
PubMed1997

Laser treatment in subjects with high-risk clinical features of age-related macular degeneration. Posterior pole appearance and retinal function.

OBJECTIVES: To verify that a few laser lesions in the posterior pole can cause drusen to resolve in patients with age-related macular degeneration, and to document central retinal sensitivity as drusen resolve. DESIGN: In a pilot study, 12 patients considered to be at high risk for sight-threatening complications from age-related macular degeneration were treated with 12 argon laser lesions in the posterior pole, with review for 12 to 24 months. RESULTS: Choroidal neovascularization developed in 1 patient 8 months after treatment, with consequent loss of central vision. In 9 of the remaining 11 patients, high-risk characteristics of drusen were reduced. Four patients had retinal pigment epithelial depigmentation, and all maintained 20/40 visual acuity at 12 months. One patient lost 3 lines of vision due to geographic atrophy after 12 months. Scotopic retinal threshold was elevated before treatment in 8 patients, compared with an age-matched comparison group. Of these, 4 patients underwent retesting 3 to 6 months after treatment, and all had improved thresholds, but only 1 patient sustained the improvement at 12 months. At 12 months, 3 of the 8 patients showed an improvement in their mean retinal threshold. Of those in whom the mean retinal threshold worsened, the mean elevation in threshold was not more than 0.6 log units. CONCLUSIONS: A few laser lesions in the posterior pole leads to resolution of drusen. There does not appear to be an increased risk for choroidal neovascularization. Retinal threshold measurements show no indication of geographic atrophy at 1 year, but cannot be excluded as a late outcome. Laser treatment may reduce the risk for profound sight-threatening lesions in age-related macular degeneration.

Aged↗
PubMed1997

In vivo fundus autofluorescence in macular dystrophies.

OBJECTIVE: To document the deviation from normal of fundus autofluorescence in patients with inherited macular dystrophies. METHODS: The intensity and spatial distribution of fundus autofluorescence was documented in 118 patients with inherited macular dystrophies by means of a confocal laser scanning ophthalmoscope, and the images were compared with the fundus appearance and fluorescein angiograms. RESULTS: Background autofluorescence appears to be elevated in all forms of macular dystrophies examined. The pale deposits at the level of the retinal pigment epithelium in disorders such as Best disease, adult vitelliform macular dystrophy, and fundus flavimaculatus were consistently associated with higher levels of autofluorescence than the background signal. There was no strong correlation between the intensity of autofluorescence and the fluorescein angiographic sign of a dark choroid. Increased levels of autofluorescence were present in a subject with a mutation known to cause macular dystrophy but in whom there were no manifest ophthalmoscopic or functional abnormalities. CONCLUSIONS: All dystrophies examined have in common accumulation of autofluorescent material in the retinal pigment epithelium to a greater degree than that seen with age. The abnormal high background autofluorescence associated with inherited macular dystrophies confirms the impression derived from histological studies that these disorders affect the entire retinal pigment epithelium. The lack of correlation between autofluorescence and the presence of a dark choroid implies that there may be different fluorophores in different disorders. The pale deposits at the level of the retinal pigment epithelium-Bruch membrane seen in macular dystrophies have similar autofluorescence characteristics. This technique may be useful in detecting the abnormal phenotype in early disease.

Adolescent↗
PubMed1997

Fourier transform analysis of human corneal endothelial specular photomicrographs.

Fourier analysis of in vivo human corneal endothelial cell structure was investigated using specular photomicrographs for a range of ages from less than one year to over 70. The theoretical basis for this analysis was investigated using mathematical models of cell structures where the elements determining their form could be modified in a controlled and quantified manner. The resulting Fourier transform properties were related to properties of cell structure. The experimental factors underlying this analysis were then studied using digitized images of corneal endothelial cells. It was found that the Fourier transforms provided quantitative descriptions of population cell size and organisation. For the smaller, more regular cell structure from the younger eyes, the expected larger rings of the Fourier transforms were demonstrated. Specular photomicrographs of older eyes gave rise to smaller diameter rings in their Fourier transforms. These results are consistent with the previous studies which used manual tracings of human endothelial cell patterns. This is the first demonstration of the direct Fourier analysis of clinical human corneal specular photomicrographs.

Adolescent↗