Edward Wylegala

Anterior segment imaging: Fourier-domain optical coherence tomography versus time-domain optical coherence tomography.

PURPOSE: To compare anterior segment measurements and morphology of 2 optical coherence tomography (OCT) systems. SETTING: Department of Ophthalmology, District Railway Hospital, and the Nursing Department and Social Medical Issues, Health Care Division, Silesian Medical University, Katowice, Poland. METHODS: In normal eyes and in eyes with corneal and trabecular–iris angle disorders, the central corneal thickness (CCT), trabecular–iris angle, and angle‐opening distance at the nasal and temporal angles were measured 3 times during 1 visit using the Visante time‐domain OCT system and the RTVue‐100 Fourier‐domain corneal anterior module OCT system. Anterior segment morphology was assessed and compared. RESULTS: Fifty‐four eyes were evaluated. The mean values (±SD) by time‐domain OCT and Fourier‐domain OCT were, respectively, automatic CCT, 535 ± 33.07 μm and 538 ± 31.82 μm; manual CCT, 545 ± 30.91 μm and 542 ± 30.57 μm; nasal trabecular–iris angle, 34.7 ± 9.5 degrees and 35.2 ± 8.9 degrees; temporal trabecular–iris angle, 35.3 ± 8.5 degrees and 35.5 ± 9 degrees; nasal angle‐opening distance, 435 ± 95 μm and 444 ± 98 μm; and temporal angle‐opening distance, 443 ± 103 μm and 452 ± 99 μm. There was no significant difference between mean values, and they were highly correlated. On morphologic analysis, time‐domain OCT had lower resolution; however, all anterior chamber structures were visible on 1 image. Fourier‐domain OCT provided precise information about small areas of the anterior chamber. CONCLUSION: Fourier‐domain OCT provided accurate anterior eye segment measurements that agreed with those obtained with time‐domain OCT.

Management of pseudophakic bullous keratopathy by combined Descemet-stripping endothelial keratoplasty and intraocular lens exchange

PURPOSE: To evaluate visual recovery results in 11 patients with anterior pseudophakia and corneal endothelial dysfunction who had Descemet‐stripping endothelial keratoplasty (DSEK) combined with anterior chamber intraocular lens (IOL) removal and scleral fixation of a posterior chamber IOL. SETTING: Department of Ophthalmology, District Railway Hospital Katowice, Katowice, Poland. METHODS: Eleven consecutive patients had DSEK combined with IOL exchange. Corneal transparency, central corneal thickness (CCT), endothelial cell density (ECD), visual outcomes, and complication rates were measured during the follow‐up. RESULTS: The mean age of patients was 76 years. All corneas remained clear during the mean 19.3‐month follow‐up. At the last visit, the mean uncorrected visual acuity was 0.16 (range 0.001 to 0.50) and the mean best corrected visual acuity, 0.36 (range 0.001 to 0.80). The mean spherical equivalent was +0.30 diopter (D) (range −2.00 to +2.25 D) and the mean astigmatism, 2.20 D (range 1.25 to 3.00 D). Three eyes with endothelial disk detachment required reinjection of air. Corneal rejection was observed in 1 eye 3 months postoperatively. Two eyes had flap erosion over the fixation suture. The mean CCT was 0.837 μm preoperatively and 0.605 μm postoperatively. The mean ECD was 3198 cells/mm2 in donor lenticules and 2048 cells/mm2 at the last follow‐up visit. Endothelial cell loss was 36%. CONCLUSION: Descemet‐stripping endothelial keratoplasty combined with anterior chamber IOL replacement with a scleral‐fixated posterior chamber IOL was a safe method for the management of pseudophakic bullous keratopathy.

Hydrogel membranes based on genipin-cross-linked chitosan blends for corneal epithelium tissue engineering.

Novel polymeric hydrogel scaffolds for corneal epithelium cell culturing based on blends of chitosan with some other biopolymers such as hydroxypropylcellulose, collagen and elastin crosslinked with genipin, a natural substance, were prepared. Physicochemical and biomechanical properties of these materials were determined. The in vitro cell culture experiments with corneal epithelium cells have indicated that a membrane prepared from chitosan–collagen blend (Ch–Col) provided the regular stratified growth of the epithelium cells, good surface covering and increased number of the cell layers. Ch–Col membranes are therefore the most promising material among those studied. The performance of Ch–Col membranes is comparable with that of the amniotic membrane which is currently recommended for clinical applications.

Comparison of Three Intraocular Pressure Measurement Methods Including Biomechanical Properties of the Cornea

PURPOSE The aim of this study was to show the usefulness of three methods for measuring IOP: Goldmann applanation tonometry, rebound tonometry, and Ultra-High-Speed Scheimpflug technology. METHODS The examined group consisted of 96 patients (192 eyes), including 63 women and 33 men with a mean age of 59.3 ± 19.9 years. Together, 152 healthy eyes and 40 eyes with different pathologies were examined. Intraocular pressure was measured using the Goldmann applanation tonometer (GAT), the Icare Pro rebound tonometer (RT), and Ultra-High-Speed Scheimpflug technology (UHS ST; Corvis ST with pachymetry). Additionally, corneal pachymetry was conducted with a Scheimpflug camera (Pentacam) and an Ultrasound Pachymeter (A-scan Plus) as a comparison for Corvis ST pachymetry. RESULTS The mean IOPs were 15.6 ± 3.75 mm Hg, 15.6 ± 3.5 mm Hg, and 16.1 ± 4.0 mm Hg when measured with the GAT, the RT, and the UHS ST, respectively. The mean central corneal thickness (CCT) was 543.7 ± 52.7 μm, 547.9 ± 54.0 μm, and 556.25 ± 38.8 μm as measured with the UHS ST, the Pentacam, and the Ultrasound Pachymeter, respectively. In comparison between devices, there was a significant difference between IOP values measured with the GAT and the RT versus the UHS ST (P < 0.001), and there was no significant difference between GAT and RT (P = 0.5). No significant differences were observed in CCT measured with the UHS ST, Pentacam, and Ultrasound Pachymeter. CONCLUSIONS We showed that the RT Icare Pro ensures IOP measurements that are more comparable with the measurements obtained with the GAT than the measurements that are provided by UHS ST.

Anterior segment optical coherence tomography in eye injuries.

BackgroundTo evaluate the usefulness of anterior segment optical coherence tomography (AS OCT) for initial diagnosis and for monitoring treatment results in eye injury cases.MethodsWe examined 38 eyes of 34 patients with different types of ocular injuries: penetrating injury (eight eyes), perforating injury (two eyes), intraocular foreign body (four eyes), ocular burn (nine eyes), contusion (13 eyes), and lamellar laceration (two eyes). The mean age of the patients was 33.8 years. AS OCT examination was performed at the initial visit, directly after injury, and repeated as treatment progressed. Both anterior chamber components and corneal pachymetry were evaluated.ResultsSlit-lamp examination did not provide a clear diagnosis in three eyes after contusion because of a nontransparent cornea. In one case of a 44-year-old male patient, only corneal edema was noticed during slit-lamp examination, whereas AS OCT revealed Descemet’s membrane detachment. In a 17-year-old male patient with blood infiltrating the cornea, OCT revealed acute angle closure with a pupillary block. In patients with corneal burns, OCT was valuable for monitoring the corneal healing progress after amniotic membrane application. OCT was also useful for determining whether a lamellar or penetrating technique should be applied in patients that qualified for corneal transplantation. In patients with foreign bodies, AS OCT was helpful in establishing the localization and size of the foreign body.ConclusionsAS OCT is a very valuable tool in ophthalmic departments dealing with ocular trauma, for early diagnosis and for monitoring treatment progress.

Fully automatic algorithm for the analysis of vessels in the angiographic image of the eye fundus

BackgroundThe available scientific literature contains descriptions of manual, semi-automated and automated methods for analysing angiographic images. The presented algorithms segment vessels calculating their tortuosity or number in a given area. We describe a statistical analysis of the inclination of the vessels in the fundus as related to their distance from the center of the optic disc.MethodsThe paper presents an automated method for analysing vessels which are found in angiographic images of the eye using a Matlab implemented algorithm. It performs filtration and convolution operations with suggested masks. The result is an image containing information on the location of vessels and their inclination angle in relation to the center of the optic disc. This is a new approach to the analysis of vessels whose usefulness has been confirmed in the diagnosis of hypertension.ResultsThe proposed algorithm analyzed and processed the images of the eye fundus using a classifier in the form of decision trees. It enabled the proper classification of healthy patients and those with hypertension. The result is a very good separation of healthy subjects from the hypertensive ones: sensitivity - 83%, specificity - 100%, accuracy - 96%. This confirms a practical usefulness of the proposed method.ConclusionsThis paper presents an algorithm for the automatic analysis of morphological parameters of the fundus vessels. Such an analysis is performed during fluorescein angiography of the eye. The presented algorithm automatically calculates the global statistical features connected with both tortuosity of vessels and their total area or their number.

Usefulness of anterior segment optical coherence tomography in Descemet membrane detachment.

Purpose To evaluate the usefulness of anterior segment optical coherence tomography (OCT) in diagnosis, choosing the treatment method, and monitoring the treatment outcomes in Descemet membrane detachment (DMD). Methods We retrospectively reviewed the clinical data for 14 eyes of 13 patients: 8 eyes with DMD after cataract surgery, 2 eyes after deep anterior lamellar keratoplasty (DALK), 2 eyes of 1 patient with Ehlers-Danlos type VI syndrome, 1 eye after contusion, and 1 eye with spontaneous corneal edema of unknown origin. We used OCT to confirm or make the diagnosis, evaluate the configuration of detachment, and monitor treatment results. Results DMD was diagnosed in 12 eyes, based on the slit lamp examination. In 2 eyes, because of a very hazy view due to corneal edema, DMD was diagnosed based on OCT findings. We chose the treatment method based on DMD configuration evaluated by OCT examination. Eight eyes were treated conservatively and 6 eyes underwent intracameral air injection with additional ab externo stab incisions. In 12 eyes, Descemet membrane reattached successfully. In 2 eyes of 1 patient with Ehlers-Danlos syndrome, the detachment remained, but corneal thickness had decreased. After anterior chamber air tamponade, we observed the decrease of corneal thickness within 7 days. Conclusions OCT is useful in precise evaluation of DMD configuration and choosing the treatment method, but has a very limited role in diagnosis and monitoring the treatment results, where the clinical examination is the most important indicating factor. (Eur J Ophthalmol 2009; 19: 723–8)

Optical coherence angiography: A review.

Background: Retinal vascular diseases are one of the most common causes of blindness in the developed world. Optical Coherence Tomography Angiography (OCT-A) is a new noninvasive method that uses several algorithms to detect blood movement. This enables the creation of high-resolution vascular images with contrast depicting motionless tissue. Methods: This review presents the results of articles relevant to age-related macular degeneration (AMD), diabetic retinopathy (DR), and OCT-A. The OCT-A technique can successfully be used in the diagnosis of neovascularization, retinal vein occlusion (RVO) and retinal artery occlusion (RAO), vessel abnormalities and even anterior segment neovascularization. OCT-A can also be applied to compute data such as vessel density, and flow index in both superficial and deep plexuses. Results: Many studies have compared fluorescein angiography with OCT-A. Other studies have reported differences in vascular density in AMD patients and have compared them with people having healthy eyes. Although OCT-A offers rapid picture acquisition, high repeatability and resolution, it also has many drawbacks. The most common are: motion artifacts, projections from overlying vessels and limited field of view. An interesting new application is the possibility to assess changes during antivascular endothelial growth factor (anti-VEGF) therapy. Another function of OCT-A is the possible application in the study of choriocapillaries in many fields of ocular pathology. Conclusion: OCT-A is a new promising method that allows the visualization of the retinal vascular network and the counting of blood flow parameters. This technique provides reliable images useful in clinical routines.

Automatic analysis of selected choroidal diseases in OCT images of the eye fundus

IntroductionThis paper describes a method for automatic analysis of the choroid in OCT images of the eye fundus in ophthalmology. The problem of vascular lesions occurs e.g. in a large population of patients having diabetes or macular degeneration. Their correct diagnosis and quantitative assessment of the treatment progress are a critical part of the eye fundus diagnosis.Material and methodThe study analysed about 1’000 OCT images acquired using SOCT Copernicus (Optopol Tech. SA, Zawiercie, Poland). The proposed algorithm for image analysis enabled to analyse the texture of the choroid portion located beneath the RPE (Retinal Pigment Epithelium) layer. The analysis was performed using the profiled algorithm based on morphological analysis and texture analysis and a classifier in the form of decision trees.ResultsThe location of the centres of gravity of individual objects present in the image beneath the RPE layer proved to be important in the evaluation of different types of images. In addition, the value of the standard deviation and the number of objects in a scene were equally important. These features enabled classification of three different forms of the choroid that were related to retinal pathology: diabetic edema (the classification gave accuracy ACC1 = 0.73), ischemia of the inner retinal layers (ACC2 = 0.83) and scarring fibro vascular tissue (ACC3 = 0.69). For the cut decision tree the results were as follows: ACC1 = 0.76, ACC2 = 0.81, ACC3 = 0.68.ConclusionsThe created decision tree enabled to obtain satisfactory results of the classification of three types of choroidal imaging. In addition, it was shown that for the assumed characteristics and the developed classifier, the location of B-scan does not significantly affect the results. The image analysis method for texture analysis presented in the paper confirmed its usefulness in choroid imaging. Currently the application is further studied in the Clinical Department of Ophthalmology in the District Railway Hospital in Katowice, Medical University of Silesia, Poland.

Deep lamellar keratoplasty for various corneal lesions

Purpose To evaluate the efficacy and safety of deep lamellar keratoplasty (DLK) as a method for treating various diseases of corneal stroma with unaffected endothelium. Methods DLK was performed in 31 eyes of 31 patients with corneal stroma opacity without endothelial abnormalities. Surgical procedures included deep removal of corneal stroma 7.5 mm in diameter with the use of viscoelastic or 0.02% trypan blue solution, exposing Descemet membrane in the central area of about 5 mm across including the area of pupil, and grafting a corneal lenticule. In three cases of postinflammatory stromal scars with coexisting limbal stem cell deficiency, limbal stem cell grafting was additionally performed. Main outcome measures were best-corrected visual acuity (BCVA) and postoperative astigmatism. Results Intraoperative perforation of Descemet membrane with the necessity of converting the procedure into penetrating keratoplasty occurred in five cases (16.1%) and one patient underwent penetrating keratoplasty on the seventh day after DLK due to persistent double anterior chamber. These six patients were excluded from the study. Postoperative BCVA ranged from 0.1 to 1.0 and astigmatism from 1.2 to 4.7 D. Postoperative complications were loose sutures, ocular hypertension, Descemet membrane detachment, and corneal melting. Conclusions DLK is an effective procedure for treating various diseases of corneal stroma with unaffected endothelium. This technique as an extraocular procedure seems to be the treatment of choice in mentally retarded patients.