Dariusz Dobrowolski

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.

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.

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.

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.

Cultivated Oral Mucosa Epithelium in Ocular Surface Reconstruction in Aniridia Patients

Purpose. Efficacy of cultivated oral mucosa epithelial transplantation (COMET) procedure in corneal epithelium restoration of aniridia patients. Methods. Study subjects were aniridia patients (13 patients; 17 eyes) with irregular, vascular conjunctival pannus involving visual axis who underwent autologous transplantation of cultivated epithelium. For the procedure oral mucosa epithelial cells were obtained from buccal mucosa with further enzymatic treatment. Suspension of single cells was seeded on previously prepared denuded amniotic membrane. Cultures were carried on culture dishes inserts in the presence of the inactivated with Mitomycin C monolayer of 3T3 fibroblasts. Cultures were carried for seven days. Stratified oral mucosa epithelium with its amniotic membrane carrier was transplanted on the surgically denuded corneal surface of aniridia patients with total or subtotal limbal stem cell deficiency. Outcome Measures. Corneal surface, epithelial regularity, and visual acuity improvement were evaluated. Results. At the end of the observation period, 76.4% of the eyes had regular transparent epithelium and 23.5% had developed epithelial defects or central corneal haze; in 88.2% of cases visual acuity had increased. VA range was from HM 0.05 before the surgery to HM up to 0.1 after surgery. Conclusion. Application of cultivated oral mucosa epithelium restores regular epithelium on the corneal surface with moderate improvement in quality of vision.

Metabolic Profile of Keratoconic Cornea

Abstract Purpose: To investigate the difference in metabolic profile of keratoconic and normal corneas using two different analysis methods. Methods: Keratoconic corneas were obtained from patients (aged 19–27) during transplantation surgery. Control samples were obtained from human donors (aged 61–75) 1–8u2009h post-mortem. The metabolic profile of tissues was investigated with high-resolution magic angle spinning 1H nuclear magnetic resonance (NMR) spectroscopy and high performance liquid chromatography (HPLC). Results: Nine amino acids and 20 metabolites were assigned with HPLC and NMR spectroscopy, respectively. No significant biochemical difference was revealed between keratoconic and control samples, which represent distant age groups. Conclusions: It suggests that development of keratoconus might be related to the accelerated ageing of the cornea. This issue warrants further studies.

NMR Spectroscopy of Human Eye Tissues: A New Insight into Ocular Biochemistry

Background. The human eye is a complex organ whose anatomy and functions has been described very well to date. Unfortunately, the knowledge of the biochemistry and metabolic properties of eye tissues varies. Our objective was to reveal the biochemical differences between main tissue components of human eyes. Methods. Corneas, irises, ciliary bodies, lenses, and retinas were obtained from cadaver globes 0-1/2 hours postmortem of 6 male donors (age: 44–61 years). The metabolic profile of tissues was investigated with HR MAS 1H NMR spectroscopy. Results. A total of 29 metabolites were assigned in the NMR spectra of the eye tissues. Significant differences between tissues were revealed in contents of the most distant eye-tissues, while irises and ciliary bodies showed minimal biochemical differences. ATP, acetate, choline, glutamate, lactate, myoinositol, and taurine were identified as the primary biochemical compounds responsible for differentiation of the eye tissues. Conclusions. In this study we showed for the first time the results of the analysis of the main human eye tissues with NMR spectroscopy. The biochemical contents of the selected tissues seemed to correspond to their primary anatomical and functional attributes, the way of the delivery of the nutrients, and the location of the tissues in the eye.

Comparative Study of Anterior Eye Segment Measurements with Spectral Swept-Source and Time-Domain Optical Coherence Tomography in Eyes with Corneal Dystrophies

Purpose. To compare anterior eye segment measurements and morphology obtained with two optical coherence tomography systems (TD OCT, SS OCT) in eyes with corneal dystrophies (CDs). Methods. Fifty healthy volunteers (50 eyes) and 54 patients (96 eyes) diagnosed with CD (epithelial basement membrane dystrophy, EBMD = 12 eyes; Thiel-Behnke CD = 6 eyes; lattice CD TGFBI type = 15 eyes; granular CD type 1 = 7 eyes, granular CD type 2 = 2 eyes; macular CD = 23 eyes; and Fuchs endothelial CD = 31 eyes) were recruited for the study. Automated and manual central corneal thickness (aCCT, mCCT), anterior chamber depth (ACD), and nasal and temporal trabecular iris angle (nTIA, tTIA) were measured and compared with Bland-Altman plots. Results. Good agreement between the TD and SS OCT measurements was demonstrated for mCCT and aCCT in normal individuals and for mCCT in the CDs group. The ACD, nTIA, and tTIA measurements differed significantly in both groups. TBCD, LCD, and FECD caused increased CCT. MCD caused significant corneal thinning. FECD affected all analyzed parameters. Conclusions. Better agreement between SS OCT and TD OCT measurements was demonstrated in normal individuals compared to the CDs group. OCT provides comprehensive corneal deposits analysis and demonstrates the association of CD with CCT, ACD, and TIA measurements.

Corneal Epithelial Scaffolds Based on Chitosan Membranes Containing Collagen and Keratin

Novel biodegradable and resorbable polymeric membranes that can function as supports for corneal epithelial cells cultures were developed. The materials used to synthesize these supports are natural polymers (i.e., chitosan, collagen and keratin [7 and 17% w/w]). The membranes were crosslinked with a natural crosslinker, genipin. The physicochemical, mechanical, and biological properties of the membranes were determined. It was found that the addition of keratin results in the appearance of antibacterial properties against Escherichia coli and in increased elasticity of the membranes. GRAPHICAL ABSTRACT

Differences in Surgical Management of Corneal Perforations, Measured over Six Years

Purpose. To report the surgical approach, anatomical and functional results, and complications in the group of patients with corneal perforation. Materials and Methods. 247 eyes with corneal perforation were operated on between January 2010 and July 2016. The three surgical procedures, dependent on size and location of perforation, were performed: full-sized penetrating keratoplasty, corneoscleral patch graft, and anterior lamellar keratoplasty. The eyes underwent the minimum 6-month follow-up visit. Results. Between January 2010 and July 2016, 247 surgeries were performed: 116 penetrating keratoplasties, 117 corneoscleral patch grafts, and 14 anterior lamellar keratoplasties. More than one procedure was necessary in 32 eyes. Final improvement of the visual acuity, within a gain of 2 or more lines with the Snellen test, was achieved in 56 operated eyes. To achieve better final visual acuity, 75 eyes required successive surgical treatment. Complications of the surgery comprised persistent epithelial defect, glaucoma or ocular hypertension, corneal oedema, graft melting, loose corneal sutures, reinfection, anterior synechiae and fibrinoid membranes, and endophthalmitis. In 26 eyes, the treatment failure was reported. Conclusions. There is no one general-purpose surgical technique to treat corneal perforations. The complex nature of this pathology remains the individual, careful but also very distinct and multifactorial approach.