Diane Ruschel Marinho

Segmentation of the optic disk in color eye fundus images using an adaptive morphological approach

The identification of some important retinal anatomical regions is a prerequisite for the computer aided diagnosis of several retinal diseases. In this paper, we propose a new adaptive method for the automatic segmentation of the optic disk in digital color fundus images, using mathematical morphology. The proposed method has been designed to be robust under varying illumination and image acquisition conditions, common in eye fundus imaging. Our experimental results based on two publicly available eye fundus image databases are encouraging, and indicate that our approach potentially can achieve a better performance than other known methods proposed in the literature. Using the DRIVE database (which consists of 40 retinal images), our method achieves a success rate of 100% in the correct location of the optic disk, with 41.47% of mean overlap. In the DIARETDB1 database (which consists of 89 retinal images), the optic disk is correctly located in 97.75% of the images, with a mean overlap of 43.65%.

A coarse-to-fine strategy for automatically detecting exudates in color eye fundus images

The detection of exudates is a prerequisite for detecting and grading severe retinal lesions, like the diabetic macular edema. In this work, we present a new method based on mathematical morphology for detecting exudates in color eye fundus images. A preliminary evaluation of the proposed method performance on a known public database, namely DIARETDB1, indicates that it can achieve an average sensitivity of 70.48%, and an average specificity of 98.84%. Comparing to other recent automatic methods available in the literature, our proposed approach potentially can obtain better exudate detection results in terms of sensitivity and specificity.

Fovea center detection based on the retina anatomy and mathematical morphology

In this work, we present a new fovea center detection method for color eye fundus images. This method is based on known anatomical constraints on the relative locations of retina structures, and mathematical morphology. The detection of this anatomical feature is a prerequisite for the computer aided diagnosis of several retinal diseases, such as Diabetic Macular Edema. The proposed method is adaptive to local illumination changes, and it is robust to local disturbances introduced by pathologies in digital color eye fundus images (e.g. exudates). Our experimental results using the DRIVE image database indicate that our method is able to detect the fovea center in 37 out of 37 images (i.e. with a success rate of 100%). Using the DIARETDB1 database, our method was able to detect the fovea center in 92.13% of all tested cases (i.e. in 82 out of 89 images). These results indicate that our approach potentially can achieve a better performance than comparable methods proposed in the literature.

A morphologic two-stage approach for automated optic disk detection in color eye fundus images

A new adaptive morphological method for the automatic detection of the optic disk in digital color eye fundus images is presented in this paper. This method has been designed to detect the optic disk center and the optic disk rim. In our experiments with the DRIVE and DIARETDB1 databases, the proposed method was able to detect the optic disk center with 100% and 97.75% of accuracy, respectively. We considered correct all automatically detected optic disk location that is within the borders of the optic disk marked manually. Using our proposed method, the rim of the optic disk was detected in all images of the DRIVE database with average sensitivity and specificity of 83.54% and 99.81%, respectively, and on the DIARETDB1 database with average sensitivity and specificity of 92.51% and 99.76%, respectively.

Femoral and acetabular revision using impacted nondemineralized freeze-dried bone allografts

BackgroundFavorable results have been obtained by the use of deep-frozen bone allografts in total hip arthroplasty. However, owing to the shortage of deep-frozen allografts and the risk of infectious disease, other materials have been studied, such as sterile nondemineralized freeze-dried allografts. The aim of this study was to describe midterm clinical outcomes and radiographic bone incorporation of human freeze-dried bone grafts in 42 revision total hip arthroplasty procedures using cancellous impacted bone grafting.MethodsThis report presented clinical and radiographic evidence of allograft incorporation in 42 hip reconstructions performed between 1996 and 2002. The patient group included 13 (31%) men and 29 (69%) women with mean ± SD age of 63 ± 14 years (range 28–80 years). Meanfollow-upwas 82 months (range 63–127) months. Clinical analysis was based on the D’Aubigné-Postel score. Radiographic incorporation was defined according to specific criteria.ResultsThe D’Aubigné and Postel criteria showed adequate outcome in 38 (90%) of the patients. The radiographic evaluation revealed that allograft remodeling and incorporation were found in 39 (93.0%) and 36 (86.5%) of acetabular and femoral cases, respectively. The overall graft survival rate at an average follow-up of 8 years (range 5–10 years) was 90%.ConclusionsBone grafts obtained by the lyophilization process developed and carried out in our tissue bank provide suitable grafts for revision total hip arthroplasty. Clinical and radiographic midterm results were excellent, indicating that nondemineralized freeze-dried bone allografts are suitable for replacing deep-frozen grafts.

Orbscan II and double-K method for IOL calculation after refractive surgery

BackgroundPrecise IOL calculation in post-refractive surgery patients is still a challenge for the cataract surgeon. The purpose of this study is to test whether adding Orbscan II values into the double-K method improves IOL calculation in this group of patients.MethodsA prospective study with 43 eyes previously submitted to refractive surgery that underwent cataract extraction. IOL calculation was performed with double-K method. Post-K value was derived from Orbscan total-mean power map. The average corneal curvature of the general population (43.8D) was used as the pre-K value. Refraction results 30 days after surgery were compared with refraction that would be obtained if we used: (1) post-K values from keratometry, (2) post-K values from topography, and (3) pre-K values from Orbscan total-mean power. Anterior chamber depth measures obtained with the IOL Master and Orbscan II were compared.ResultsMean postoperative spherical equivalent (SE) was −0.25u2009±u20091.10 D in eyes submitted to radial keratotomy , –1.04u2009±u20091.42 D in eyes previously submitted to myopic Lasik, and +0.05u2009±u20091.76 D in those submitted to hyperopic surgeries. Had we inputted post-K values derived from keratometer and from topography, we would have obtained significantly higher postoperative refractive errors in eyes previously submitted to myopic refractive surgery (pu2009<u20090.05). Refractions using pre-K derived from the central 8 mm Orbscan instead of 43.8 D were similar in all studied groups (pu2009>u20090.05). Anterior chamber depth measured with IOL Master or Orbscan were similar.ConclusionsOrbscan measurements used as the post-K values into the double-K method provide a precise IOL calculation, especially in post myopic refractive surgery patients.

A morphologic three-stage approach for detecting exudates in color eye fundus images

An efficient detection of exudate lesions in color eye fundus images is an essential stage for grading the Diabetic Macular Edema automatically. In this work, we present a new automatic method based on mathematical morphology to locate exudate lesions. The proposed method was evaluated using the publicly available DIARETDB1 database, and it obtains 72.21% of mean sensitivity and 98.97% of mean specificity. This results indicate that our approach potentially can achieve a better performance than other known methods proposed in the literature.

Optical coherence tomography image in gelatinous drop-like corneal dystrophy: case report

Gelatinous drop-like corneal dystrophy is a rare disorder with few cases described in the present literature. The following report will show how difficult it is to diagnose this disease in early stages. Modern image exams, such as optical coherence tomography helps to diagnose and can be crucial to establish the best treatment. We will present the histopathological changes and clinical features in this unusual dystrophy.

Experiência inicial com a ceratoprótese de Dohlman-Doane: relato de casos

PURPOSEnTo describe 9 eyes in 8 patients who received Dohlman-Doane type 1 keratoprosthesis (KPro) with a mean follow-up of 11.2 months (2 to 25 months).nnnMETHODSnA retrospective, non-comparative interventional case series. Previous corneal disease was alcaline burn in 4 eyes, multiple graft failure in 3 eyes, Stevens-Johnson syndrome in 1 eye and thermal injury in 1 eye. Best corrected visual acuity (BCVA) was hand motions or worse in all patients. Glaucoma was present preoperatively in 3 eyes and received Ahmed valve implantation.nnnRESULTSn88,9% eyes achieved BCVA of better than or equal to 20/100, and 44,4% better than or equal to 20/40. In the postoperative period, 3 eyes developed posterior capsule opacity treated with YAG laser capsulotomy; 3 retroprosthetic membrane treated with tPA injection or steroids; 2 glaucoma in clinical treatment; 1 corneal melting, treated with donor cornea bottom exchange; and 1 fungic endophthalmitis, treated with corneal transplant, anterior vitrectomy, KPro and intraocular lens explantation, and specific intravitreal and endovenous treatment.nnnCONCLUSIONnDohlman-Doane K-Pro seems to be a good option for cases of corneal blindness with poor prognosis for traditional penetrating keratoplasty. Its main advantage is not requesting systemic immunossuppression. Best results were achieved in non-immune diseases.

A Case-Control Study on the Oxidative Balance of 50% Autologous Serum Eye Drops

Importance. Autologous serum (AS) eye drops are recommended for severe dry eye in patients with ocular surface disease. No description of the antioxidant balance of AS eye drops has been reported in the literature. Objective. This study sought to evaluate the total reactive antioxidant potential (TRAP) and concentration of reactive oxygen species (ROS) in samples of 50% AS eye drops and their correlations with the demographic characteristics and lifestyle habits of patients with ocular surface disease and healthy controls. Design. This was a case-control study with a 3-month follow-up period. Participants. 16 patients with severe dry eye disease of different etiologies and 17 healthy controls matched by age, gender, and race were included. Results. TRAP and ROS were detected at all evaluated times. There were no differences in the mean ROS (p = 0.429) or TRAP (p = 0.475) levels between cases and controls. No statistically significant differences in the concentrations of ROS or TRAPs were found at 0, 15, or 30 days (p for ROS = 0.087 and p for TRAP = 0.93). Neither the demographic characteristics nor the lifestyle habits were correlated with the oxidative balance of the 50% AS eye drops. Conclusions and Relevance. Both fresh and frozen 50% AS eye drops present antioxidant capacities and ROS in an apparently stable balance. Moreover, patients with ocular surface disease and normal controls produce equivalent AS eye drops in terms of oxidative properties.