Rationale and Design of the Hamburg City Health Study.

The Hamburg City Health Study (HCHS) is a large, prospective, long-term, population-based cohort study and a unique research platform and network to obtain substantial knowledge about several important risk and prognostic factors in major chronic diseases. A random sample of 45,000 participants between 45 and 74 years of age from the general population of Hamburg, Germany, are taking part in an extensive baseline assessment at one dedicated study center. Participants undergo 13 validated and 5 novel examinations primarily targeting major organ system function and structures including extensive imaging examinations. The protocol includes validate self-reports via questionnaires regarding lifestyle and environmental conditions, dietary habits, physical condition and activity, sexual dysfunction, professional life, psychosocial context and burden, quality of life, digital media use, occupational, medical and family history as well as healthcare utilization. The assessment is completed by genomic and proteomic characterization. Beyond the identification of classical risk factors for major chronic diseases and survivorship, the core intention is to gather valid prevalence and incidence, and to develop complex models predicting health outcomes based on a multitude of examination data, imaging, biomarker, psychosocial and behavioral assessments. Participants at risk for coronary artery disease, atrial fibrillation, heart failure, stroke and dementia are invited for a visit to conduct an additional MRI examination of either heart or brain. Endpoint assessment of the overall sample will be completed through repeated follow-up examinations and surveys as well as related individual routine data from involved health and pension insurances. The study is targeting the complex relationship between biologic and psychosocial risk and resilience factors, chronic disease, health care use, survivorship and health as well as favorable and bad prognosis within a unique, large-scale long-term assessment with the perspective of further examinations after 6 years in a representative European metropolitan population.

OCT angiography analysis of retinal vessel density in primary open-angle glaucoma with and without Tafluprost therapy.

BACKGROUND: Primary open-angle glaucoma (POAG) is a progressive neurodegenerative disease which leads to irreversible blindness. An elevated intraocular pressure (IOP) is considered to be the main risk factor for the disease progression. It is known that retinal blood flow is altered in POAG eyes. Tafluprost, a prostaglandin analogue which lowers the IOP, has shown to also improve the retinal blood flow in animals. METHODS: The current study therefore evaluated the retinal vessel density in the peripapillary and macular region of POAG patients with normal IOP treated with topical Tafluprost (n = 20) compared to surgically treated patients with normal IOP (n = 22) using optical coherence tomography angiography (OCT-A). The retinal flow density was obtained after binarisation and evaluated in five sectors. RESULTS: There was a significantly higher peripapillary flow density in all sectors in Tafluprost treated eyes when compared to post-surgery eyes. The flow density in the inferior sector of the superficial plexus in the macular region was also significantly higher in the Tafluprost group. CONCLUSIONS: These results indicate that Tafluprost not only lowers IOP, but may also enhance retinal blood flow in POAG patients with a normal IOP.

[Photorefractive Keratectomy (PRK) as a Procedure for Correction of Residual Refractive Errors after Radial Keratotomy]. / Photorefraktive Keratektomie (PRK) zur Korrektur der Restfehlsichtigkeit nach radiärer Keratotomie.

BACKGROUND: A large number of myopic patients were treated by radial keratotomy (RK) in recent years. Despite being effective in many cases, the refractive results of this surgical intervention proved to be of limited predictability, and it frequently resulted in over- or under-correction in the long term. In this study, we discuss the intermediate and long-term results of a topography-guided photorefractive keratotomy (PRK) in a consecutive series of patients who were previously treated for myopia by radial keratotomy. MATERIALS AND METHODS: In this retrospective case series, we examined the refraction and visual acuity in a consecutive series of patients-16 eyes-who were treated by PRK for residual refractive errors after radial keratotomy in the past. Mean follow up was 41 months (min. 9, max. 96). RESULTS: All treated eyes showed an improvement in uncorrected visual acuity, and 56% had an improvement in corrected visual acuity. No serious or sight-threatening complications were recorded. Refraction was stable throughout the study period in all patients. CONCLUSIONS: In this case series, photorefractive keratotomy was shown to be an effective treatment method for secondary ametropia after radial keratotomy. Apart from the correct planning and execution of the PRK, it is of critical importance to inform the patients about the limitations and the anticipated refractive result of the procedure.

[The 100 Most Often Articles on Glaucoma Research: a Bibliometric Analysis]. / Die 100 meistzitierten Studien der Glaukomforschung: eine bibliometrische Analyse.

BACKGROUND: Bibliometric science employs statistical and quantitative analyses to analyse the scholarly impact and characteristics of publications within a research field. The present study was initiated to analyse and quantify the 100 most often cited papers in glaucoma research. MATERIALS AND METHODS: The databases of the Institute for Scientific Information were utilised for the identification of articles published from 1900 to December 2016. All glaucoma articles were identified that had been published in 109 relevant journals and which had been cited at least 200 times. The top 100 articles were selected for further analysis of authorship, source journal, number of citations, citation rate, geographic origin, article type, and level of evidence. RESULTS: The publication dates of the 100 most often cited articles ranged from 1966 to 2011, with the greatest number of articles published in the 1990s. Citations per article ranged from 258 to 1908. All articles were published in 18 of the 109 journals. The leading countries of origin were the U. S. A., followed by the U. K. The study focussed on two main clinical articles (diagnostics; epidemiology) and basic research articles. The number of citations per article was greatest for articles published in the 2000s. Most articles provided level III evidence, followed by levels I and II. CONCLUSION: The majority of the most cited articles were published in three of the top-ranked journals. Most clinical articles dealt with epidemiology and diagnostics. Individuals who authored multiple articles in the list often focussed on one of these two areas. Most studies were conducted in the U. S. A. and presented level III clinical outcomes. This indicates that even studies with small case series or cohort studies can attract attention.

An Automated Approach for Localizing Retinal Blood Vessels in Confocal Scanning Laser Ophthalmoscopy Fundus Images.

In this work, we present a rules-based method for localizing retinal blood vessels in confocal scanning laser ophthalmoscopy (cSLO) images and evaluate its feasibility. A total of 31 healthy participants (17 female; mean age: 64.0 ± 8.2 years) were studied using manual and automatic segmentation. High-resolution peripapillary scan acquisition cSLO images were acquired. The automated segmentation method consisted of image pre-processing for gray-level homogenization and blood vessel enhancement (morphological opening operation, Gaussian filter, morphological Top-Hat transformation), binary thresholding (entropy-based thresholding operation), and removal of falsely detected isolated vessel pixels. The proposed algorithm was first tested on the publically available dataset DRIVE, which contains color fundus photographs, and compared to performance results from the literature. Good results were obtained. Monochromatic cSLO images segmented using the proposed method were compared to those manually segmented by two independent observers. For the algorithm, a sensitivity of 0.7542, specificity of 0.8607, and accuracy of 0.8508 were obtained. For the two independent observers, a sensitivity of 0.6579, specificity of 0.9699, and accuracy of 0.9401 were obtained. The results demonstrate that it is possible to localize vessels in monochromatic cSLO images of the retina using a rules-based approach. The performance results are inferior to those obtained using fundus photography, which could be due to the nature of the technology.

A novel temporary keratoprosthesis technique for vitreoretinal surgery.

AIM: To investigate the safety of vitreoretinal surgery when using a soft contact lens as a temporary keratoprosthesis (TKP) in patients with severe corneal opacifications. METHODS: Three patients with simultaneous corneal and vitreoretinal pathology were treated with a soft contact lens that was used as a TKP to facilitate vitreoretinal surgery. The soft contact lens was fixated with sutures onto the globe so that no leakage was possible. RESULTS: Vitreoretinal surgery with excellent fundus view was possible in all cases. The soft contact lens allowed safe central and peripheral vitrectomy. Surgery was successful in all cases. CONCLUSION: A soft contact lens properly fixated on the globe can successfully replace a TKP. This surgical procedure has several advantages like one size fits all, low costs, and easy access to the material.

Contamination of multi dose eyedrops in the intra and perioperative context.

In this study, we examined the rate of contamination of multi-dose ophthalmic solutions in the operating theatre and the underlying risk for infection by examining the microbiological load on the tips of the dispenser bottles. A total of 245 samples of eye drop bottles were collected and analysed between June 2018 and January 2019. All were collected in the operating theatre of the University Eye Hospital Hamburg-Eppendorf. Contamination of the dropper tip occurred in 2% of the samples. Although the prevalence of contamination was low, the results of this study reveal the possibility of contamination of multi-dose eyedrops even when used by health care professionals in the controlled environment of an operating theatre. Following these results, we recommend the use of single-dose eyedrops in the pre- and intraoperative context.

Reliability of the ocular trauma score for the predictability of traumatic and post-traumatic retinal detachment after open globe injury.

AIM: To elucidate the question of whether the ocular trauma score (OTS) and the zones of injury could be used as a predictive model of traumatic and post traumatic retinal detachment (RD) in patients with open globe injury (OGI). METHODS: A retrospective observational chart analysis of OGI patients was performed. The collected variables consisted of age, date, gender, time of injury, time until repair, mechanism of injury, zone of injury, injury associated vitreous hemorrhage, trauma associated RD, post traumatic RD, aphakia at injury, periocular trauma and OTS in cases of OGI. RESULTS: Totally 102 patients with traumatic OGI with a minimum of 12mo follow-up and a median age at of 48.6y (range: 3-104y) were identified. Final best corrected visual acuity (BCVA) was independent from the time of repair, yet a statistically significant difference was present between the final BCVA and the zone of injury. Severe trauma presenting with an OTS score I (P<0.0001) or II (P<0.0001) revealed a significantly worse BCVA at last follow up when compared to the cohort with an OTS score >III. OGI associated RD was observed in 36/102 patients (35.3%), whereas post traumatic RD (defined as RD following 14d after OGI) occurred in 37 patients (36.3%). OGI associated RD did not correlate with the OTS and the zone of injury (P=0.193), yet post traumatic RD correlated significantly with zone III injuries (P=0.013). CONCLUSION: The study shows a significant association between lower OTS score and zone III injury with lower final BCVA and a higher number of surgeries, but only zone III could be significantly associated with a higher rate of RD.

Determination of Ischemia Onset Based on Automatically Generated Spectralis SD-OCT Values in Acute Central Retinal Artery Occlusion.

Acute central retinal artery occlusion (CRAO) induces a time-dependent increase in retinal thickness. By manually measuring the relative retinal thickness increase (RRTI) in comparison to the contralateral eye based on optical coherence tomography (OCT), ischemia onset within the past 4.5 hours could be determined with 100% sensitivity and 94.3% specificity. To enable examiner-independent and quicker diagnostics, we analyzed the RRTI using the automatic retinal thickness measurement. In this retrospective study, 28 eyes were evaluated with an acute CRAO (<46 hours). All patients received a Spectralis SD-OCT image of both eyes. The RRTI was calculated for the ETDRS sectors using the Segmentation Module for Single Retinal Layer Analysis. Receiver operating characteristic (ROC) analysis was performed to determine patients ≤4.5 hours by RRTI. In all sectors, time to OCT (TTO) and RRTI correlated positively. The optimal cutoff point to detect CRAOs ≤4.5 hours was between 18.7% nasally and 22.9% RRTI temporally. Sensitivity and specificity varied between the sectors with 90-95% sensitivity and 89-100% specificity. In conclusion, the automatic measurement of RRTI also allows the differentiation of CRAOs within a possible therapeutic time window ≤4.5 hours and CRAOs ≥4.5 hours with a high sensitivity and specificity. Additionally, it offers quicker, easier, and a user-independent assessment of ischemia onset, helping to set a base for establishing automatic indices generated by the OCT machines.

Optical coherence tomography-based determination of ischaemia onset - the temporal dynamics of retinal thickness increase in acute central retinal artery occlusion.

PURPOSE: Acute central retinal artery occlusion (CRAO) induces ischaemic retinal oedema. The purpose of this study was to define sensitivity and specificity of optical coherence tomography (OCT) based retinal thickness analysis in determining ischaemia onset in CRAO. METHODS: The relative retinal thickness increase (RRTI) in comparison with the fellow eye was analysed retrospectively in OCT scans of 66 patients diagnosed with CRAO between January 2010 and December 2019 within 48 hr of ischaemia onset. The natural course of RRTI and the sensitivity and specificity of OCT-based determination of ischaemia onset in identifying CRAO within 4.5 hr using the RRTI were evaluated. RESULTS: Relative retinal thickness increase (RRTI) in acute CRAO follows a hyperbolic curve with a steep incline within the early phase after which it reaches a plateau. Optical coherence tomography (OCT)-based retinal thickness analysis in CRAO allows to differentiate patients with ischaemia onset within the past 4.5 hr or thereafter with a sensitivity of 100% and a specificity of 94.3%. CONCLUSION: Relative retinal thickness increase (RRTI) allows to identify CRAO patients that are eligible for a potentially beneficial reperfusion therapy within a therapeutic window of 4.5 hr with a high accuracy. Especially in patients with unknown ischaemia onset, this diagnostic tool could be of major importance in the future clinical management.

Ocular Blood Volume Index Based on Scattering Properties of Retinal Vessels Using Spectral Domain Optical Coherence Tomography.

Introduction: The evaluation of retinal vessels and the retinal blood flow is important for ocular diseases. We introduce a spectral domain optical coherence tomography (SD-OCT) based method for facilitating a retinal blood vessel analysis using the scattering properties of retinal vessels. The intensity of the distal shadow of vessels caused by the scattered signal is measured, correlated with the pulsatile ocular blood flow (POBF), and its repeatability is analyzed. Methods: About 20 eyes of 20 healthy, young participants (mean age 23.15 years, standard deviation 2.3 years) were included in the analysis. Participants underwent ophthalmic diagnostics including three repeated SD-OCT examinations and measurement of POBF. The vessel shadow intensity analysis is based on peripapillary SD-OCT scans and automatically analyses the intensity of the distal vessel shadow compared to its surroundings. Results: The distal shadow of arteries in SD-OCT scans correlated with the POBF (r = 0.647, p = 0.002). Furthermore, the shadow intensity correlated with the established morphological arterio-venous ratio. The evaluation of repeatability was performed using the interclass correlation coefficient (ICC), showing good repeatability for individual vessels (ICC = 0.825) and arteries (ICC = 0.820). Conclusions: In summary, we indicate that the scattering properties of retinal vessels in SD-OCT images might correlate with the vessel morphology and for retinal arteries with the retinal blood flow volume as well. Further studies are needed to establish this method's sensitivity and specificity in participants with retinal and cardiovascular diseases.

Optical coherence tomography angiography analysis of macular flow density in glaucoma.

PURPOSE: Modifications in ocular blood flow may play a significant role in glaucoma development. Optical coherence tomography angiography (OCT-A) is based on the detection and analysis of the reflection behaviour of motion in a static environment and therefore is able to quantify the retinal flow density. We used this new technology to examine the density of the active flow vasculature in the macular area in glaucoma patients compared to healthy patients. METHODS: Thirty patients with primary open-angle glaucoma (mean age: 72.6 ± 7.1 years) and 21 healthy patients (mean age: 70.3 ± 8.6 years) were recruited. Patients received perimetry and OCT measurements of the peripapillary retinal nerve fibre layer thickness (RNFLT) and macular retinal thickness and OCT-A of the macular area in the superficial and deep retinal (DR) plexus. Flow density of the OCT-A scan was calculated by binarisation and quantification of the pixel density. RESULTS: Macular flow density was globally and nasally reduced in glaucoma patients in the superficial (globally: p = 0.0203; nasally: p = 0.0003) and DR plexus (globally: p = 0.0113, nasally: p < 0.0001). There was no significant difference between the superficial retina and the DR concerning the flow density. Flow density showed no significant correlation with perimetry results, RNFLT or retinal segment thickness. CONCLUSION: Patients with glaucoma exhibit a reduced macular flow density measured by OCT-A compared to controls. The independence of the macular flow density of the retinal segment thickness changes could indicate an altered vascular element in patients with glaucoma.

The top 100 papers in dry eye - A bibliometric analysis.

PURPOSE: Citation analysis represents one of the best currently available methods for quantifying the impact of articles. Bibliometric studies list the ''best sellers'' in a single field of interest. The purpose of the present study was to identify and analyze the most frequently cited papers in dry eye research that may be of high interest for researchers and clinicians. METHODS: We reviewed the database of the Institute for Scientific Information to identify articles published from 1900 to September 2016. All dry eye articles published in 59 ophthalmology journals were identified. The top 100 articles were selected for further analysis of authorship, source journal, number of citations, citation rate, geographic origin, article type, and level of evidence. RESULTS: The 100 most-cited articles were published between 1983 and 2011, with most of them in the 2000s. The number of citations per article ranged from 96 to 610, and was greatest for articles published in the 2000s. Each of these articles was published in one of 15 journals. Most articles represented Level-III evidence, followed by Levels II and I. CONCLUSIONS: The present study focusing on dry eye research revealed that 55% of the most-cited articles came from the U.S. and 18% from Japan. Diagnostics and therapy were the areas of focus of most of the clinical articles; 13% of the most cited papers were review articles. This analysis provides researchers and clinicians with a detailed overview on the most cited dry eye papers over the past decades.

Association between optical coherence tomography based retinal microvasculature characteristics and myocardial infarction in young men.

Incident myocardial infarction (MI) is a leading cause of adult mortality in the United States. However, because MI has a relatively low incidence in the young population, little information exists on the disease in younger adults. Because the retina has the unique quality that its vasculature is readily and noninvasively visible, the retina is frequently studied to evaluate correlations between vessels and cardiovascular diseases. In the current study, we evaluated the retinal microvasculature of patients who had experienced an MI before 50 years of age (n = 53 subjects) and age- and sex-matched patients who had not experienced an MI (n = 53 patients). We used circular optical coherence tomography (OCT) scans to image peripapillary venules and arterioles. The diameter of each vessel was measured and the respective arterial-venous ratio (AVR) was calculated. We did not detect any significant differences between MI and control subjects in retinal vessel calibre or AVR.

Predicting Surgical Success in Patients with Idiopathic Epiretinal Membrane Using the Spectral-Domain Optical Coherence Tomography Segmentation Module for Single Retinal Layer Analysis.

INTRODUCTION: Idiopathic epiretinal membrane (ERM) is a proliferation of cells formed on the internal surface of the retina and may cause a slow decrease in visual acuity (VA). The aim of this study was to evaluate the individual layers of the retina by optical coherence tomography (OCT) before and after vitrectomy with ERM peeling in order to refine surgical decision-making. METHODS: Forty-seven eyes of 45 patients (aged 55-87 years) with ERM were enrolled retrospectively from a tertiary referral center. OCT examination was performed preoperatively and at a mean of 3.2 months postoperatively in all cases. Nine retinal surfaces were subjected to automated all-layer segmentation using the manufacturer's software and assessed for their correlation with VA. RESULTS: There was a significant correlation between the initial retinal morphology and change in VA postoperatively. Patients who gained at least two lines of VA had a significantly higher total retinal perimacular volume and retinal nerve fiber layer (each p < 0.0001) preoperatively. CONCLUSION: Patients with high preoperative retinal volumes and therefore increased tractive components seemed to benefit more from surgery than those with low tractive components.

Optical Coherence Tomography-Based Scattering Properties of Retinal Vessels in Glaucoma Patients.

PURPOSE: Clinical trials have demonstrated that retinal blood flow deficiencies are present in patients with open-angle glaucoma (OAG). We introduce a method for facilitating retinal vessel analysis: The intensity of the distal shadow of vessels in optical coherence tomography (OCT) caused by the scattered signal is analyzed, compared between healthy subjects and OAG patients and correlated with OCT angiography (OCT-A) flow density. PATIENTS AND METHODS: We recruited 80 patients with diagnosed OAG (mean age 63.4 ± 13.2 years) and 80 healthy age-matched control subjects for comparison, and 20 patients for the correlation with OCT-A flow density. Patients received perimetry, peripapillary OCT measurements, and selected patients OCT-A of the papillary area. The vessel shadow intensity (VSI) is based on peripapillary OCT scans: the intensity of the distal vessel shadow was automatically compared to its surroundings, separated by arteries and veins. Flow density of the OCT-A scan was calculated by binarization and quantification of the pixel density. RESULTS: The VSI for arteries was in OAG patients with 7.52 ± 2.62 [%] significantly lower compared to healthy subjects (9.03 ± 3.38 [%], p = 0.0029). In veins, the VSI was as well significantly lower for OAG patients (14.9 ± 3.59 [%]) compared to healthy subjects (17.46 ± 4.45 [%], p < 0.0001). Furthermore, in OAG patients there was a significant correlation of mean deviation of the visual field results with the veins' VSI (p = 0.0006; r = -0,454). There was no significant correlation of scattering properties with OCT-A flow density (p > 0.05). CONCLUSIONS: We conclude that the OCT-based analysis of the scattering properties of retinal vessels differs significantly between patients with OAG and healthy subjects. Furthermore, changes in the scattering properties of veins correlated with the stage of the disease in terms of visual field deficits. These properties might complement existing measurements of ocular blood flow including OCT-A flow density.

The Top 100 Papers of 25 Years of Macular Imaging Using Optical Coherence Tomography.

We analyzed and quantified the 100 most frequently cited papers in macular imaging using optical coherence tomography (OCT). The databases of the Institute for Scientific Information databases utilized for identification of articles in macular imaging using OCT over the last 25 years since the introduction of OCT in ophthalmology. All articles containing "optical coherence tomography" and "retina" without "glaucoma". The publication dates of the 100 most-cited articles ranged from 1991 to 2015, with the greatest number of articles published in the 2000s, while the total number of citations per article was greatest for articles published in the 1990s. Most studies were conducted in the U.S. and represented Level-IV clinical outcome studies indicating that also small case series or cohort studies could gain attention. The top 5 senior authors contributed to 39 of the 100 selected publications and accrued a total of 66.0% of all citations of those articles.

Bruch's Membrane Opening Minimum Rim Width Measurement with SD-OCT: A Method to Correct for the Opening Size of Bruch's Membrane.

A precise evaluation of the retinal nerve fiber layer thickness (RNFLT) is key for diagnosing and monitoring glaucoma. The Bruch's membrane opening minimum rim width (BMO-MRW) has been proposed as a reproducible assessment of the optic nerve. The BMO-MRW measures the minimum distance from the BMO to the internal limiting membrane. We propose an approach to correct the BMO-MRW using the BMO size for increased accuracy in interindividual comparisons in future studies. Eighty-one healthy patients received SPECTRALIS spectral domain optical coherence tomography measurements for the peripapillary RNFLT and BMO-MRW. We calculated a BMO size-corrected BMO-MRW using the mean BMO size of our cohort. BMO size was defined using the manufacturer-provided BMO area and manually measured BMO perimeter. We observed that the BMO-MRW correlated highly with the perimeter (r = -0.553, p < 0.0001) and the area of the BMO (r = -0.546, p < 0.0001). Using these parameters, we provided a corrected BMO size-adjusted BMO-MRW which was better correlated with the RNFLT compared to the noncorrected one (z = -3.3495, p = 0.0004). We demonstrated the dependency of the BMO-MRW on ONH size. Furthermore, we showed the superiority of the corrected BMO-MRW using either the manually measured optic nerve head perimeter or the automatically provided ONH for future studies.

Retinal degeneration in progressive supranuclear palsy measured by optical coherence tomography and scanning laser polarimetry.

This cross-sectional study compared the retinal morphology between patients with progressive supranuclear palsy (PSP) and healthy controls. (The retinal nerve fiber layer (RNFL) around the optic disc and the retina in the macular area of 22 PSP patients and 151 controls were investigated by spectral domain optical coherence tomography (SD-OCT). Additionally, the RNFL and the nerve fiber index (NFI) were measured by scanning laser polarimetry (SLP). Results of RNFL measurements with SD-OCT and SLP were compared to assess diagnostic discriminatory power. Applying OCT, PSP patients showed a smaller RNFL thickness in the inferior nasal and inferior temporal areas. The macular volume and the thickness of the majority of macular sectors were reduced compared to controls. SLP data showed a thinner RNFL thickness and an increase in the NFI in PSP patients. Sensitivity and specificity to discriminate PSP patients from controls were higher applying SLP than SD-OCT. Retinal changes did not correlate with disease duration or severity in any OCT or SLP measurement. PSP seems to be associated with reduced thickness and volume of the macula and reduction of the RNFL, independent of disease duration or severity. Retinal imaging with SD-OCT and SLP might become an additional tool in PSP diagnosis.

Evaluation of Retinal Vessel Morphology in Patients with Parkinson's Disease Using Optical Coherence Tomography.

PURPOSE: The retina has been found affected in Parkinson's disease (PD). It is unclear if this is due to neurodegeneration of local dopamine-dependent retinal cells, a result of central nervous degeneration including the optic nerve or retinal small vessel disease. This study aimed to detect changes of the retinal vasculature in PD patients compared to controls. METHODS: We examined 49 PD patients and 49 age- and sex-matched healthy controls by spectral domain optical coherence tomography (SD-OCT) with a circular scan centred at the optic disc. Vessels within the retinal nerve fibre layer were identified by an automated algorithm and thereafter manually labelled as artery or vein. Layer segmentation, vessel lumen and direct surrounding tissue were marked automatically with a grey value and the contrast between both values in relation to the surrounding tissue was calculated. The differences in these grey value ratios among subjects were determined and used as an indicator for differences in vessel morphology. Furthermore, the diameters of the veins and arteries were measured and then compared between the groups. RESULTS: The contrast of retinal veins was significantly lower in PD patients compared to controls, which indicates changes in vessel morphology in PD. The contrast of arteries was not significantly different. Disease duration, disease stage according to Hoehn and Yahr or age did not influence the grey value ratios in PD patients. Vessel diameter in either veins or arteries did not differ between subject groups. The contrast of retinal veins contralateral to the clinically predominant and first affected side was significantly lower compared to the ipsilateral side. CONCLUSION: Our data show a potential difference of the retinal vasculature in PD patients compared to controls. Vascular changes in the retina of PD patients might contribute to vision-related complaints in PD.