[ChatGPT and the German board examination for ophthalmology: an evaluation]. / ChatGPT und die deutsche Facharztprüfung für Augenheilkunde: eine Evaluierung.

PURPOSE: In recent years artificial intelligence (AI), as a new segment of computer science, has also become increasingly more important in medicine. The aim of this project was to investigate whether the current version of ChatGPT (ChatGPT 4.0) is able to answer open questions that could be asked in the context of a German board examination in ophthalmology. METHODS: After excluding image-based questions, 10 questions from 15 different chapters/topics were selected from the textbook 1000 questions in ophthalmology (1000 Fragen Augenheilkunde 2nd edition, 2014). ChatGPT was instructed by means of a so-called prompt to assume the role of a board certified ophthalmologist and to concentrate on the essentials when answering. A human expert with considerable expertise in the respective topic, evaluated the answers regarding their correctness, relevance and internal coherence. Additionally, the overall performance was rated by school grades and assessed whether the answers would have been sufficient to pass the ophthalmology board examination. RESULTS: The ChatGPT would have passed the board examination in 12 out of 15 topics. The overall performance, however, was limited with only 53.3% completely correct answers. While the correctness of the results in the different topics was highly variable (uveitis and lens/cataract 100%; optics and refraction 20%), the answers always had a high thematic fit (70%) and internal coherence (71%). CONCLUSION: The fact that ChatGPT 4.0 would have passed the specialist examination in 12 out of 15 topics is remarkable considering the fact that this AI was not specifically trained for medical questions; however, there is a considerable performance variability between the topics, with some serious shortcomings that currently rule out its safe use in clinical practice.

[Simple rules for orientation in transcutaneous ptosis surgery--a contribution to the surgical anatomy or: how not to get lost in the upper eyelid]. / Einfache Regeln zur Orientierung bei der transkutanen Ptosischirurgie--Ein Beitrag zur chirurgischen Anatomie des Oberlides, oder: Wie man sich im Oberlid nicht verirrt.

Surgical preparation in the upper eyelid follows well defined anatomic structures. Nevertheless, even an experienced surgeon can loose orientation in the presence of fatty degeneration, oedema or bleeding. Some simple rules can help to stay oriented and identify the landmarks. The preaponeurotic fat has a distinct colour, structure and texture and is a landmark for the levator muscle lying underneath it. This defines a first simple rule: it is not preaponeurotic fat if it does not look like preaponeurotic fat. The orbital septum may weaken and allow orbital fat to prolapse, but it stays firmly attached at the upper orbital rim. A second simple rule therefore adresses its identification: if a structure does not move with inferior tension, it cannot be muscle or fat (it must be septum). Identifying the landmarks preaponeurotic fat, orbital septum and tarsus will facilitate anatomic correlation and surgical preparation. In summary: Rule No. 1--If it does not look like preaponeurotic fat, then it isn't. Rule No. 2--If it does not move with traction, it is neither muscle nor fat (but probably septum). Rule No. 3--If things get confusing, stop and consider rules 1 and 2.

[Postoperative care and options for scar treatment in eyelid surgery]. / Postoperative Nachsorge und Möglichkeiten der Narbenbehandlung in der Lidchirurgie.

Oculoplastic surgery places special demands on postoperative care because of the functional importance of the eyelids for the ocular surface. We present an overview of postoperative care after surgical eyelid interventions. All options, limits and the scientific evidence are discussed with a special focus on the treatment of postoperative edema, analgesia, infection prophylaxis and scar treatment.

[Management of anticoagulants in ophthalmic surgery-a survey among ophthalmic surgeons in Germany]. / Umgang mit gerinnungshemmenden Substanzen in der Ophthalmochirurgie ­ eine Umfrage unter Ophthalmochirurgen in Deutschland.

INTRODUCTION: As our population ages and comorbidities rise, ophthalmic surgeons are increasingly faced with patients on anticoagulant therapy or with clotting disorders. The ophthalmic surgeon has to weigh the perioperative risk of haemorrhage when anticoagulation continues against the risk of thromboembolism caused by discontinuation or changing the patient's medication (bridging, switching, cessation). There are currently no guidelines or recommendations. METHODS: A survey was sent to the DOG (German Ophthalmologic Society) divisions and associated surgical organizations to determine the status quo. A questionnaire was sent out and filled out by the different groups of specialists. RESULTS: All four divisions of the DOG and four associated organizations returned completed questionnaires. Surgical interventions were listed that are carried out during anticoagulant therapy without exceptions, as well as interventions that were classified to require medical adjustment. Although the assessments varied, general consensus was achieved regarding interventions not requiring adjustments due to anticoagulants (i. e., intravitreal injection, cataract surgery, laser and corneal operations, simple muscle surgery), and those interventions requiring adjustments in medications (glaucoma operations, complex retina surgery, eye socket surgery, complex surgery of the lid). CONCLUSION: Main result of this survey was the specification of serious bleeding complications which are permanent vision loss and re-operation. They could serve as endpoint parameters for essential future investigations. Nevertheless, this survey makes clear that the decision about an adjustment of anticoagulant medication in ophthalmic surgery is currently made individually and not based on established standards.

The cavernous body of the human efferent tear ducts: function in tear outflow mechanism.

PURPOSE: To determine the structure and function of a system of large blood vessels integrated in the bony canal between the orbit and the inferior nasal duct. METHODS: Thirty-one dissected lacrimal systems of adults were analyzed by using gross anatomy, histology, and electron microscopy as well as corrosion vascular casts. RESULTS: More than two thirds of the bony canal between orbit and inferior nasal duct is filled by a plexus of wide-lumened veins and arteries. The vascular system is embedded in the wall of the lacrimal sac and nasolacrimal duct and is connected to the cavernous tissue of the inferior turbinate. Three types of blood vessels can be distinguished inside the vascular tissue that surrounds the lumen of the lacrimal passage: barrier arteries, capacitance veins, and throttle veins. CONCLUSIONS: The surrounding vascular plexus of the lacrimal sac and nasolacrimal duct is comparable to a cavernous body. While regulating the blood flow, the specialized blood vessels permit opening and closing of the lumen of the lacrimal passage, effected by the bulging and subsiding of the cavernous body, and at the same time regulate tear outflow. Other functions such as drainage of absorbed tear fluid components and a role in immunologic response are under discussion as well. Malfunctions in the cavernous body may lead to disturbances in the tear outflow cycle, ocular congestion, or total occlusion of the lacrimal passages. Variations in the conditions for swelling of the cavernous tissue may have led to the (mistaken) description of valves in the lacrimal passage.

Detection of natural peptide antibiotics in human nasolacrimal ducts.

PURPOSE: To determine the expression and production of antimicrobial peptides by mucosal cells of the lacrimal passage in healthy and pathologic states. METHODS: Detection of bactericidal-permeability-increasing protein (BPI), heparin-binding protein (CAP37), human cationic antimicrobial protein (LL-37), human alpha-defensin 5 (HD5), human alpha-defensin 6 (HD6), human beta-defensin 1 (HBD-1), and human beta-defensin 2 (HBD-2) was performed by reverse transcription-polymerase chain reaction (RT-PCR). Intracellular deposition of lysozyme, lactoferrin, secretory phospholipase A(2), human neutrophil defensins (HNP-1, -2, and -3), human beta-defensin 1 (HBD-1), and human beta-defensin 2 (HBD-2) was analyzed immunohistochemically. Samples were obtained from 15 patients by surgery and from 10 cadavers. RESULTS: RT-PCR revealed BPI, CAP37, and HBD-1 mRNA in samples of healthy nasolacrimal duct epithelium. Additionally, HBD-2 mRNA was detected in epithelial samples from patients with dacryocystitis. Messenger RNAs for LL-37 and alpha-defensin 5 and 6 were absent in all samples investigated. Immunohistochemistry revealed lysozyme, lactoferrin, secretory phospholipase A(2), and HNP-1, -2, and -3 to be present in all samples, whereas HBD-1 was present only in some of the healthy and inflamed samples. Immunoreactive HBD-2 peptide was visible only in some of the inflamed samples. CONCLUSIONS: The data suggest that the human efferent tear ducts produce a broad spectrum of antimicrobial peptides. Under inflammatory conditions, changes in the expression pattern occurred, revealing induction of the human inducible defensin HBD-2 and in some cases downregulation of HBD-1 and CAP37. Antimicrobial peptides have a therapeutic potential in dacryocystitis, in that they have a broad spectrum of antimicrobial activity and accelerate epithelial healing. However, caution is appropriate, because defensins also promote fibrin formation and cell proliferation, which are key elements in scarring processes, such as dacryostenosis.

Long term efficacy of class I antiarrhythmic agents and amiodarone in patients with malignant ventricular arrhythmias.

The long term efficacy of class I antiarrhythmic drugs and of amiodarone was investigated in 34 patients with severe organic heart disease accompanied by frequent complex ventricular arrhythmias. All patients had undergone cardiac catheterisation which included coronary angiography, and each patient underwent a short and a long term study phase. During the short term study 6 class I antiarrhythmic agents were administered orally in a randomised, single-blind fashion. The drugs investigated were disopyramide, flecainide, mexiletine, prajmalium, propafenon and tocainide. The response was judged to be effective when there was a 90% reduction of couplets and a 100% reduction of salvos. For long term treatment the patient was given one of the agents found to be effective in the short term testing. Holter monitoring was performed after 1 week, and 1, 3 and 6 months. If the drug administered initially was later found to be ineffective, the patient was given another effective class I agent. If during the short term study or the follow-up phase there was no positive response to any class I agent, the patient was given amiodarone. In 78% of the patients, one or more of the class I agents administered short term was effective. The percentage of effectively treated patients after 1 week was 56%, and was 28, 14, and 9% after 1, 3, and 6 months' treatment, respectively. In amiodarone-treated patients there was an effective response rate of 40% after 10 days, 50% after 1 month and 70% after 3 and 6 months.

[Optical coherence tomography]. / Optische Kohärenztomographie.

Optical coherence tomography has become an established method for imaging retinal diseases. It is now an accepted method for making quantitative measurements in studies on the cause and course of macular holes, vitreoretinal traction, pigment epithelial detachment, macular edema, and diabetic retinopathy. Its potential benefit in the evaluation of age-related macular degeneration and a variety of other diseases is currently under investigation. In clinical practice optical coherence tomography images add information to the biomicroscopic findings and results of other imaging techniques or functional testing and can significantly help in making critical decisions. Its future role in routine clinical practice will depend on further technical development and the results of long-term studies.

[Endovascular treatment of extensive carotid cavernous fistulas by superior ophthalmic vein approach. Technique and illustration of two cases]. / Endovaskuläre Behandlung ausgedehnter Carotis-Cavernosus-Fisteln über die Direktpunktion der V. ophthalmica superior nach chirurgischer Freilegung. Technik und Illustration anhand zweier Fälle.

Treatment of carotid cavernous fistulas is a domain of interventional neuroradiolgy. In rare cases, however, the cavernous sinus cannot be reached by an endovascular approach, leaving the access via the superior ophthalmic vein as the last therapeutic option. History, diagnostic findings, and operative procedure for a patient with spontaneous, indirect CCF (Barrow type D) and a patient with traumatic, direct CCF (Barrow type A) are described. In both patients, curative therapeutic success could be achieved. This article focuses on the detailed description and illustration of the combined surgical/endovascular technique.

[Transposition flaps for reconstruction of deep defects of the medial eyelids. Fasciocutaneous rotations- and transposition flaps and modified pure fascial transposition flap]. / Transpositionslappenplastiken zur Rekonstruktion von tiefen Defekten des medialen Lidwinkels. Fasziokutane Rotations- und Transpositionslappenplastik und fasziale Transpositionslappenplastik.

Tumor resection in the medial canthal area may result in deep defects with involvement of the ethmoidal bone and destruction of the lacrimal ducts. While shallow defects with little involvement of bone can be covered with the classic glabellar flap, deep defects require larger fasciocutaneous flaps from the forehead that can also be used for the reconstruction of the involved medial parts of the eyelids. The preferred techniques of the median or paramedian transposition flaps and a modified paramedian fascial flap for reconstruction of the medial orbital wall and support of the orbit are described.

[Nasolacrimal ducts and the dry eye]. / Ableitende Tränenwege und Trockenes Auge.

BACKGROUND: The knowledge regarding the pathogenesis, diagnosis, and treatment of dry eye has made large advances in recent years. However, many questions are still unanswered. Although the nasolacrimal ducts are part of the tear system they have been paid nearly no attention regarding dry eye. METHODS: The present knowledge about the nasolacrimal ducts is presented and discussed in a context with dry eye. A PubMED search was conducted for articles published from 1966 to the present; in addition, review articles as well as book chapters were considered and discussions with investigators in the field were performed. RESULTS: As a draining and secretory system, the nasolacrimal ducts play a role in tear transport and non-specific immune defense. Moreover, components of tear fluid are absorbed in the nasolacrimal passage and are transported into a vascular system that surrounds the nasolacrimal sac and nasolacrimal duct. This system is comparable to a cavernous body and it is connected to the blood vessels of the outer eye. Also it is subject to vegetative control. Organized mucosa-associated lymphoid tissue (MALT) is present in the nasolacrimal ducts displaying the cytomorphological and immunophenotypic features of MALT. CONCLUSIONS: The normally constant absorption of tear fluid components into the blood vessels of the surrounding cavernous body that are connected to the blood vessels of the outer eye, could be a feedback signal for tear fluid production, which comes to a halt if these tear components are not absorbed. Thus, dry eye could be initiated. Defective stimulation of tear duct-associated lymphoid tissue (TALT) could result in abnormal immune deviation at the ocular surface leading to an autoimmunological response that causes dry eye pathology.

[Subretinal granuloma, retinal vasculitis and keratouveitis with secondary open-angle glaucoma in schistosomiasis]. / Subretinales Granulom, retinale Vaskulitis und Keratouveitis mit sekundärem Offenwinkelglaukom bei Schistosomiasis.

BACKGROUND: More than 250 million people in Africa and Asia currently suffer from schistosomiasis, however, ocular manifestations of this disease are rare in Germany. PATIENT AND FOLLOW-UP: We present the case of a 32-year-old patient from Gambia who had been resident in Germany for 3 years and suffered from a painful persistent diarrhoea, fever and a reduction of visual acuity (R > L). On admission, the patient reported a schistosomiasis in 1994, which was diagnosed by a skin test and was not adequately treated because of the side-effects of praziquantel. Vision was OD-0.75 sph 0.8, OS sc 1.0, IOD OD 31, OS 18 mmHg. Biomicroscopy: R > L fatty retrocorneal precipitates, especially in the lower circumference (ARLT), large inflammatory cells and Tyndall ++, vitreous with large inflammatory cells, Fundus: OD at 11 o'clock large subretinal granuloma in the periphery. Serum lysozyme was elevated (22.2 mg/l, normal range 10-17 mg/l), a syphilis stage II-III (TPHA 1:5000, VDRL neg.) and an IgG-antibody titre for Schistosoma mansoni of > 30 micrograms/ml was detected by enzyme immunoassay. In the faeces and urine no schistosoma eggs were found. Before the specific treatment for schistosomiasis could be initiated, the patient left the hospital because of reduced ocular pain due to the corticosteroids and fear of the side-effects of the treatment. DISCUSSION: In patients who present a subretinal granuloma and report a painful persistent diarrhoea, schistosomiasis, which is one of the most frequent tropical diseases should be considered, even if they have been living in central Europe for several years. Although the disease cannot become established due to the lack of specific hosts in this area, a curative treatment should be enforced in order to prevent late manifestations of chronic inflammatory organ manifestations.

[Prevention of postenucleation syndrome: the hydroxylapatite silicone implant. Preliminary experimental studies and initial clinical experiences]. / Zur Prophylaxe des Postenukleationssyndroms: Das Hydroxylapatitsilikon-implantat. Experimentelle Vorarbeiten und erste klinische Erfahrungen.

An orbital implant after enucleation compensates for volume deficiency and increases prosthesis motility. In the literature, however, an extrusion rate of orbital implant between 10 and 25% is reported. Since the introduction of hydroxylapatic ceramics (HAC), these numbers have been reduced considerably. The HAC, which is derived from corals, has a rough surface and requires a scleral covering for implantation. The HAC, which is made in the laboratory, can be produced with smoother surfaces, so that a homoplastic covering is no longer mandatory. A composite implant was developed to improve prosthesis motility further. This consists of artificial HAC at its anterior surface to guarantee safe tissue integration; the posterior part of the implant is manufactured from silicon rubber to create a jointlike structure in Tenon's capsule. Integration of the porous HAC in the orbital soft tissues has been tested and confirmed by animal experiments. After 30 full HAC implants and 25 composite implants, only one extrusion occurred. In all other cases, compatibility proved to be excellent; transmission of the motility to the prosthesis was moderate to good. Examinations comparing prosthesis motility and computer tomographically evaluated implant motility enabled the analysis of deficits in motility transmission of the implant for the artificial eye.

[Optical coherence tomography for macular edema. Classification, quantitative assessment, and rational usage in the clinical practice]. / OCT bei Makulaödem. Klassifizierung, quantitative Beurteilung und rationaler Einsatz in der Praxis.

Optical coherence tomography (OCT) allows for morphological assessment of macular edema of various origins by producing two-dimensional images of the retina. In addition, retinal thickness can be measured quantitatively. In diabetic maculopathy, damage of the blood-retinal barrier can be indirectly assessed by locating the intraretinal fluid accumulation and the progress of maculopathy from diffuse to cystoid edema and even rupture of the retinal structure can be described as well as the formation of neurosensory retinal detachment with subretinal fluid. Increase of retinal thickness correlates with decrease in visual acuity. Detailed interpretation of OCT images can replace fluorescein angiography in certain cases, as has been shown for uveitis. In order to obtain correct classification of macular disease in routine clinical use, all images have to be completely assessed and compared to previous investigations and to the measurements of the fellow eye. More accurate normal values of retinal thickness and volume can be expected in the future. The importance of OCT in routine clinical assessment of macular edema will most probably continue to grow.

[Alpha/beta and gamma/delta T-cell receptors--analysis of conjunctival tissue of patients with ocular pemphigoid]. / Alpha/beta und gamma/delta-T-Zell-Rezeptor-Analyse an konjunktivalem Gewebe bei Patienten mit okulärem Pemphigoid.

BACKGROUND: In the conjunctiva of asymptomatic persons and patients with ocular cicatricial pemphigoid the existence and distribution of alpha/beta- and gamma/delta-T cell receptor (TCR)-positive cells has not previously been investigated. PATIENTS AND METHODS: Biopsy specimens from 20 patients with clinically diagnosed ocular cicatricial pemphigoid (OCP) were compared with 20 specimens from asymptomatic persons. Additionally, 3 specimens from patients with OCP treated with cytotoxic drugs and 8 specimens from patients who had undergone mucosal transplantation were studied. Antigen retrieval was done in deparaffinized specimens for immunohistochemical identification of alpha/beta- and gamma/delta-TCR-positive cells by monoclonal antibodies and an appropriate detection system. All steps were performed in triplicate, and negative control sera were applied. RESULTS: alpha/beta-TCR-positive cells were observed in the conjunctival epithelium and stroma of all the asymptomatic persons and in all patients with OCP. gamma/delta-TCR-positive cells were found in 4 out of 20 patients with OCP in epithelial sites, but not in asymptomatic persons. Patients with OCP who had received cytotoxic treatment exhibited neither alpha/beta- nor gamma/delta-TCR-positive cells. Staining sites of alpha/beta-TCR-positive cells changed from membrane-bound to nuclear in patients who had undergone mucosal transplantation, and were cytoplasmic rather than membrane-bound in gamma/delta-TCR positive cells. CONCLUSIONS: This study presents preliminary evidence for the existence of distinct T-cell subsets in the conjunctiva of healthy persons and of patients with OCP. Further functional studies in fresh tissue material may provide better insights into the role of defined T-cell subsets in the immunopathogenesis of autoimmune diseases of the outer eye such as OCP.

[Tear outflow. Impact of mucins and TFF-peptides]. / Tränenabfluss. Bedeutung von Muzinen und TFF-Peptiden.

The epithelial lining of the lacrimal sac and the nasolacrimal duct consists of pseudo-stratified, columnar epithelia rich in goblet cells. Major secretory products of the epithelial cells are mucins together with TFF peptides. Expression and distribution of several mucins and TFF peptides in the human efferent tear ducts was investigated by means of reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. mRNAs for all the mucins investigated, MUC1, MUC2, MUC4, MUC5AC, MUC5B and MUC7, were detected in healthy human lacrimal sacs and nasolacrimal ducts. Both MUC5AC and MUC5B were detected in goblet cells forming intraepithelial mucous glands. MUC7 together with TFF3 occurred only in columnar epithelial cells of the efferent tear duct system. The mucin diversity of the efferent tear ducts could enhance tear transport and antimicrobial defense. The absence of some mucins in non-functioning although patent segments of the lacrimal passage, suggests that mucins ease tear flow through the efferent tear ducts because these conditions are associated with epiphora. Disorders in the balance of single mucins could be of importance with regard to dacryostenosis, dacryocystitis and dacryolith formation.

[Lacrimal duct treatment with ring intubation in injuries of the upper and lower eyelids]. / Tränenwegsversorgung mittels Ringintubation bei Verletzungen des Ober- und Unterlids.

BACKGROUND: Treating injuries of the lacrimal system with a silicon intubation is an approved method to prevent post-traumatic epiphora. MATERIALS AND METHODS: Between 1990 and 1999, operations were carried out on 44 patients with injuries of the canaliculi with silicon ring intubations. Interesting for us were the age distribution, causes of injuries, localisation and mid- to long-term postoperative complications. RESULTS: The age of the patients was between 1.75 and 74 years, 48% of the injuries were caused by household accidents, 23% by violence, 20% by traffic accidents and 9% by job-related accidents. The canaliculus inferior was injured in 68% of all patients. We found 10 postoperative complications, e.g. ectropia, a too long silicon ring or granuloma. We found a positive anatomical readapted lacrimal system in 88% and 12% of our patients complained of distinct to severe epiphora. CONCLUSIONS: The treatment of lacrimal laceration with a silicon intubation is an excellent method but special care should be taken with correct positioning of the lid margin.

[Final clinical indications and etiology in 1,023 enucleations. Descriptive databank evaluation with SPSS software in variable response mode with dummy variables]. / Letzter klinischer Anlass und Atiologie bei 1023 Enukleationen. Deskriptive Datenbankauswertung mittels SPSS-Software im Antwortvariablenmodus mit Platzhaltervariablen.

BACKGROUND: A new data bank developed for ophthalmopathology using a computer-generated, multidigital data code is expected to be able to accomplish complex clinicopathologic correlations of diagnoses and signs, as provided by (multiple) clinical events and histopathologically proven etiologies, and to facilitate the documentation of new data. PATIENTS AND METHODS: In the ophthalmopathology laboratory 2890 eyes were examined between January 20, 1975 and December 12, 1996. The main diagnoses and patient data from this 22-year period were recorded. To facilitate the presentation of data, a 10-year period with eyes of 976 patients enucleated from December, 1986 to December, 1996 was chosen. Principal and secondary diagnoses served for establishing the data bank. The frequencies of successive histologic and clinical diagnoses were evaluated by a descriptive computing program using an SPSS-multi-response mode with dummy variables and a categorical variable listing of the software (SPSS version 10.0) classified as (a) non-filtered random, (b) filtered by multiple etiologies, and (c) filtered by multiple events. RESULTS: The principal groups (e.g., histologic diagnoses concerning etiology) and subgroups (e.g., trauma, neoplasia, surgery, systemic diseases, and inflammations) were defined and correlated with 798 separate diagnoses. From 11 diagnoses/events ascribed to the clinical cases, 11,198 namings resulted. CONCLUSIONS: Thus, a comparative study of complex etiologies and events leading to enucleation in different hospitals of a specific area may be performed using this electronic ophthalmopathologic data bank system. The complexity of rare disease and integration into a superimposed structure can be managed with this custom-made data bank. A chronologically and demographically oriented consideration of reasons for enucleation is thus feasible.

Optical coherence tomography for retinal thickness measurement in diabetic patients without clinically significant macular edema.

BACKGROUND AND OBJECTIVE: To evaluate the potential of optical coherence tomography (OCT) as a screening method for retinal thickness measurements in diabetic patients. PATIENTS AND METHODS: We used a previously described pattern of six 5 mm OCT scans through the center of fixation in 45 diabetic patients without clinically significant macular edema: 22 patients (group 1) had no diabetic retinopathy (ETDRS classification); 18 (group 2) had nonproliferative retinopathy; 5 patients with peripheral neovascularization did not enter statistical analysis; 25 normal healthy subjects were used as a control group. Retinal thickness was measured at five locations in each scan: in the fovea, at the foveal rim, and outside the macula. Measurements were identified in nonaligned images and taken from raw data A-scans. Locations were grouped into hemispheres, quadrants and rings, and mean values tested for statistically significant differences using Mann-Whitney U-Wilcoxon rank sum W test. RESULTS: Differences in retinal thickness were found to be significant in the macula (controls vs group 2 P = 0.0266), at the foveal rim (controls vs group 1 and 2: P = 0.0386 and P = 0.0193), in the nasal and superior hemisphere (controls vs group 2: P = 0.0251 and P = 0.0187), and in the superior nasal quadrant (controls vs group 1 and group 1 vs group 2: P = 0.0022 and P = 0.0462). CONCLUSIONS: Significant differences of retinal thickness between patients with diabetic retinopathy and normals can be detected by OCT even in the absence of clinically significant macular edema. Significant differences between diabetic patients with and without retinopathy are most likely to be found in the superior nasal quadrant.

Structural changes of the retina in retinal vein occlusion--imaging and quantification with optical coherence tomography.

BACKGROUND AND OBJECTIVE: To evaluate the potential of optical coherence tomography (OCT) for imaging and quantifying structural changes in the retinal architecture following venous occlusive disease. PATIENTS AND METHODS: We studied 20 patients with retinal venous occlusive disease: 5 patients suffered from branch retinal vein occlusion (BRVO), and 15 from central retinal vein occlusion (CRVO). Patients with CRVO were studied within 72 hours after the first onset of symptoms. Patients were examined by OCT after a complete ophthalmologic examination including fluorescein angiography. A standard set of linear scans through the center of fixation and individual scans over areas of special interest were performed. Scans were qualitatively evaluated and quantitative measurements were performed on single A-scans at 5 locations of linear scans. Measurements were taken in the center of fixation, at the foveal rim, and at the edge of the scan. We measured total retinal thickness, thickness of cystoid spaces, and thickness of the highly reflective outer band. RESULTS: OCT produced detailed images of retinal thickening, intra- and subretinal hemorrhage, intra- and subretinal fluid accumulation, and formation of intraretinal cystoid spaces. Quantitative evaluation revealed a mean central retinal thickness of 274 +/- 181 microm (72-760 microm) in patients with central retinal vein occlusion. Visual acuity did not correlate with central or extrafoveal retinal thickness. CONCLUSION: Optical coherence tomography is a useful imaging technique for studying changes of retinal architecture following venous occlusive disease. Even minor changes like localized subretinal fluid accumulation or beginning epiretinal membrane formation can be visualized in detail. In contrast to other diseases like diabetic maculopathy, quantitative assessment of macular thickness does not correlate to visual acuity. Nevertheless, because of detailed imaging, OCT might become a useful tool in the follow-up and treatment of individual patients.