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J Conrath

Publications and source records attributed to J Conrath.

At least 19 recordsLinked to original sources
PubMed2006

Evaluation of the effect of JPEG and JPEG2000 image compression on the detection of diabetic retinopathy.

AIMS: To compare the effect of classic Joint Photographic Experts Group (JPEG) and JPEG2000 compression algorithms on detection of diabetic retinopathy (DR) lesions. METHODS: In total, 45 colour fundus photographs obtained with a digital nonmydriatic fundus camera were saved in uncompressed Tagged Interchanged Files Format (TIFF) format (1.26 MB). They were graded jointly by two retinal specialists at a 1 month interval for soft exudates, hard exudates, macular oedema, newvessels, intraretinal microvascular abnormalities (IRMA), and retinal haemorrhages and/or microaneurysms. They were compressed to 118, 58, 41, and 27 KB by both algorithms and 24 KB by classic JPEG, placed in random order and graded again jointly by the two retina specialists. Subjective image quality was graded, and sensitivity, specificity, positive and negative predictive values, and kappa statistic were calculated for all lesions at all compression ratios. RESULTS: Compression to 118 KB showed no effect on image quality and kappa values were high (0.94-1). Image degradation became important at 27 KB for both algorithms. At high compression levels, IRMA and HMA detection were most affected with JPEG2000 performing slightly better than classic JPEG. CONCLUSION: Performance of classic JPEG and JPEG2000 algorithms is equivalent when compressing digital images of DR lesions from 1.26 MB to 118 KB and 58 KB. Higher compression ratios show slightly better results with JPEG2000 compression, but may be insufficient for screening purposes.

Algorithms↗
PubMed2006

[Bilateral corneal endothelial decompensation after postsepticemia coma].

We report a case of unexplained bilateral corneal endothelial decompensation after a coma. A 71-year-old man with no medical history presented with bilateral endothelial decompensation that required penetrating keratoplasty of the left eye combined with cataract surgery. This coma was caused by septicemia originally due to staphylococcus infection following catheter placement in preparation for a CT scan. Visual acuity of the left eye was 20/400 and 20/100 in the right eye when the patient awoke from the coma. After examination, we noted only stromal thickening and Descemet membrane folds causing corneal edema predominating OS. The rest of the exam was normal. Six months after surgery, visual acuity improved to 20/25. The most probable physiopathological mechanism of this decompensation is an iatrogenic complication from drugs administered during the patient's stay in intensive care (oxacillin), but we cannot rule out direct aggression of a bacterium or its toxin or the decompensation of a preexisting pathology.

Aged↗
PubMed2006

[Internal carotid artery dissection on arterial fibromuscular dysplasia causing a central retinal artery occlusion: a case report].

INTRODUCTION: We report a case of a 66-year-old woman presenting a central retinal artery occlusion with no cardiovascular risk factor, with assessment using supra-aortic artery ultrasonography showing total internal carotid artery thrombosis. OBSERVATION: When vascular thrombosis risk factors are absent, more in-depth assessment such as a supra-aortic artery angioscan can provide the diagnosis of arterial dissection on arterial fibromuscular dysplasia. CONCLUSION: Central retinal artery occlusion is a rare but severe pathology. Therefore it is very important not to neglect the etiological assessment, because it can be the revealing element of a severe pathology.

Aged↗
PubMed2005

[Quantitative and spatial analysis in image processing: study of drusen distribution from the foveal center in age-related macular degeneration].

Angiofluorograms were obtained from 58 patients presenting posterior pole drusen due to age-related macular degeneration. These frames underwent image processing by morphological mathematics algorithms. The detection sensitivity of this algorithm is 78%. We present a quantitative and spatial analysis of drusen distribution from the foveal center in the form of a graph. This technique may allow for multi-date comparisons, by using a graphic representation of this risk factor for age-related macular degeneration.

Algorithms↗
PubMed2005

Metabolic factors and the foveal avascular zone of the retina in diabetes mellitus.

AIM: To study the foveal avascular zone (FAZ) of the central retina in diabetic patients with retinopathy having undergone metabolic evaluation. METHODS: One hundred and ten digital fluorescein angiograms were chosen from our digital image bank after cross matching diabetic patient lists of the ophthalmology and endocrinology departments of our institution. The patients had undergone day visits with systemic, biological and ophthalmologic evaluation, including digital fluorescein angiography. RESULTS: Sex ratio was M 62/F 48. Average age was 52.4 years (+/- 13.8) with 44 type 1 diabetics and 66 type 2. Retinopathy was present in all patients (54 background (BDR), 30 pre-proliferative (PPDR), 26 proliferative (PDR)). Age was positively correlated with FAZ grade (47.3 years +/- 13.2 for normal FAZ, 53.8 years +/- 13.7 for abnormal FAZ, P=0.03). Lipid profile showed a protective tendency of the Apo A1 fraction of cholesterol on macular vascularization (1.7 gr./l in normal FAZ patients vs 1.43 gr./l in abnormal FAZ patients, P=0.004). Body mass index was negatively correlated with macular ischemia (28.11 if FAZ not severely altered, 25.97 if FAZ severely altered, P=0.03). CONCLUSIONS: We found possible relations between BMI and Apo A 1 cholesterol and macular vascularization which may warrant further investigation.

Adult↗
PubMed2005

Foveal avascular zone in diabetic retinopathy: quantitative vs qualitative assessment.

PURPOSE: To describe the relations between foveal avascular zone (FAZ) size and outline in patients presenting diabetic retinopathy. METHODS: 110 high-quality fluorescein angiograms from 110 diabetics were chosen from our digital retinal image databank. Patients with significant media opacities, macular scars, macular hard exsudates, high ametropia, and associated macular pathology were excluded. Both FAZ perimeter and surface area were measured with image analysis software. FAZ outline was graded according to ETDRS report Number 11 (from 0=normal to 4=capillary outline completely destroyed). Data were compared to that of 31 healthy controls. FAZ surface in diabetics was compared to that of controls and FAZ surface was compared to FAZ grade, FAZ perimeter and retinopathy stage in diabetics. Quantitative variables were compared using the U-test of Mann-Whitney or Kruskal-Wallis test and correlations between quantitative variables were estimated with the Spearmann coefficient. RESULTS: All patients presented diabetic retinopathy (54 BDR, 30 PPDR, 26 PDR). FAZ size was larger in diabetics than controls (P<0.001). In diabetics, FAZ size increased with FAZ grade (P<or=0.006 except between grades 1 and 2=NS) and with retinopathy stage (P<or=0.024). As retinopathy advanced, there was a higher proportion of altered FAZ outlines (P=0.003). CONCLUSIONS: This study confirms capillary alteration to be the cause of increase in FAZ size in diabetics and presents an alternative evaluation method of the FAZ to FAZ size measurement. No qualitative studies using the ETDRS FAZ grading scale have been performed to our knowledge.

Adult↗
PubMed2004

Molecular effects of cyclosporine and oncogenesis: a new model.

Cyclosporine A is the most commonly used immunosuppressive agent during organ transplantation. One of the most feared adverse effects of cyclosporine A is the appearance of de novo cancers. The mechanisms that lead to the genesis of such cancers are thought to be only related to a side effect of cyclosporine A: a depressed immune system. Here, we review different molecular effects induced by cyclosporine A (inhibition of DNA repair, synthesis of TGF Beta, induction of apoptosis of activated T cells, inhibition of apoptosis through the inhibition of the opening of the mitochondrial Permeability Transition Pore) and propose that cyclosporine A can promote the genesis and the spread of cancer not only because of immunosuppression but also because of its ability to facilitate DNA mutations accumulation, to diminish the clearance of altered cells and to transform cancer cells into aggressive cancer cells. This new insights into the mechanisms of genesis of cyclosporine A-related cancers should be taken into account to develop preventive strategies or new immunosuppressive strategies.

Animals↗
PubMed2004

[Branch retinal vein occlusion reveals Takayasu's arteritis].

We report a case of branch retinal vein occlusion in a 28-year-old woman that revealed Takayasu's arteritis. Somatic examination showed humeral blood pressure asymmetry and an abdominal murmur; a biological inflammatory syndrome was noted. Abdominal aortography showed marked stenosis of the superior mesenteric artery. Three of the six diagnostic criteria of Takayasu's arteritis were present in our patient, sufficing to make the diagnosis. This is the first case reported of branch retinal vein occlusion revealing Takayasu's arteritis. It is to be added to the List of atypical initial manifestations of Takayasu's arteritis such as anterior ischemic optic neuropathy. Branch retinal vein occlusion is a rare enough occurrence in a 28-year-old patient to warrant further clinical investigation.

Adult↗
PubMed2004

[Ocular metastasis of cutaneous melanoma].

We report a case of vitreal metastases from cutaneous melanoma. We describe the clinical findings and the histological aspects of the lesions, which allows us to discuss the diagnosis of masquerade syndrome and highlight the diagnostic importance of vitreous biopsy.

Eye Neoplasms↗
PubMed2004

[Penicillium chrysogenum endophthalmitis: a case report].

We report a case of Penicillium chrysogenum endophthalmitis after penetrating ocular trauma in a 9-year-old child, describing the initial management and the therapeutic adaptation after biopsy culture. After a review of endophthalmitis treatment, we discuss mycotic endophthalmitis treatment and recommend the use of intravitreal antibiotics. In this case, we used amphotericin B to treat the fungal disorder with success.

Child↗
PubMed2004

[Teaching phacosection in a tropical setting].

PURPOSE: The aim of this study was to prospectively evaluate the training of a Malagasy ophthalmologist, already proficient in classic manual extracapsular cataract extraction (ECCE), in a small incision manual technique (phacosection). MATERIALS AND METHODS: Within the activity of the Sight First program to fight blindness in Madagascar, the ophthalmologist of Majunga recruited patients presenting total white cataracts. These patients were operated by phacosection using the local hospital's usual instrumentation along with two specific phacosection instruments and extra single-use material (a precalibrated 3.2 mm knife and viscoelastic products). Peribulbar anesthesia with eye pressure was provided. Postoperative follow-up (visual acuity and corneal status) was conducted on days 1, 7 and 30. RESULTS: Forty-four eyes were operated, the first seven by the instructor assisted by the local ophthalmologist, the next 36 by the local ophthalmologist assisted by the instructor. Five postoperative complications were noted: two cases of posterior capsular rupture (one during implantation) and three cases needing reoperation with aspiration of residual cortical masses. Induced astigmatism was low and visual rehabilitation was good, with all corneas clear at day 30. DISCUSSION: The results are quite acceptable given the training period, with only two marked complications (one not related to the operative technique) and good visual rehabilitation in less than 2 weeks. This small incision technique allowed reduction of induced astigmatism and risk-free management of total white cataracts (independent of operator). CONCLUSION: Small incision manual ECCE by phacosection is a safe, possible management option for difficult cataracts in a tropical setting with only a small increase in cost. Moreover, the training of an ophthalmologist mastering classic manual ECCE appears rapid and risk-free for patients.

Adult↗
PubMed2003

[Indocyanine green angiography in age-related macular degeneration].

Indocyanine green ocular angiography was developed more than 30 years ago, but has been used commonly for less than 10 years. In exudative age-related macular degeneration, certain cases of occult neovascularization may be converted into well-defined cases, in theory allowing treatment of more patients. Neovascularization is observed as either focal hyperfluorescence (hot spot) or diffuse hyperfluorescence (plaque). Scanning laser ophthalmoscopy imaging allows for better visualization of feeder vessels, allowing even more selective treatment. Even though a multicentric, prospective, randomized study has not yet been conducted, a number of pilot studies are very encouraging concerning indocyanine green angiography-guided laser treatment.

Age Factors↗
PubMed2001

Mathematical morphology in computerized analysis of angiograms in age-related macular degeneration.

This paper deals with image processing of numerical retinal angiograms in order to facilitate diagnosis and follow-up in age-related macular degeneration (AMD) which is currently the main cause of blindness in industrialized countries. A computerized scheme using principally mathematical morphology operators is proposed for detecting and counting drusen, which are precursor lesions of the ocular fundus. In order to check the feasibility of this approach, results relative to 58 retinal images are compared with those given by three retinal specialists independently. From manual counting measures it is found that interobserver correlation coefficients lie in the range 0.71-0.78. On the other hand, a correlation coefficient of 0.89 is obtained when the average of the three expert countings is compared with the drusen number given by the computerized method. This coefficient is improved from 0.89 to 0.93 by processing only frames captured immediately after the appearance of a dye consecutive to intravenous sodium fluorescein injection. Compared to the manual analysis which is, among other things, tedious and time consuming, the computerized analysis is both quicker and more objective. Validation by the practitioner is however necessary, given possible detection errors. The proposed computerized scheme for detecting and counting drusen may be easily automated and so should prove useful in clinical studies which involve high volume analysis of retinal angiograms.

Aging↗
PubMed2001

Pinguecula and Sjögren's syndrome: two cases.

A pinguecula is a small, raised conjunctival nodule at the temporal or nasal limbus classically associated with conjunctival microtrauma from exposure to sunlight and/or to dust. We report two cases occurring during the course of Sjögren's syndrome. To our knowledge this association has never been described.

Antibodies, Antinuclear↗