Efficacy of Subthreshold Micropulse Laser for Central Serous Chorioretinopathy.

PURPOSE: To evaluate the efficacy of a subthreshold micropulse laser (SML) in patients with central serous chorioretinopathy (CSCR). METHODS: Retrospective clinical study conducted at the Departments of Ophthalmology at a university and a municipal hospital in Zurich, Switzerland. We enrolled acute and chronic CSCR patients with persistent subretinal fluid (SRF) treated with SML. Two treatment protocols (fluorescein/indocyanine green angiography or optical coherence tomography guided) were evaluated for efficacy after 3 and 6 months. The primary outcomes of the study were reduction and percentage of eyes with complete resolution of SRF 3 and 6 months after SML treatment. Secondary endpoints included changes in central subfield thickness (CST) and visual acuity (VA) after 3 and 6 months. RESULTS: The study involved 37 eyes (35 patients, 48.6% chronic). A statistically significant reduction in SRF height and CST could be shown, irrespective of SRF duration, type of CSCR, or chosen guidance after 3 and 6 months: SRF - 40 µm (p < 0.01), CST - 52 µm (p < 0.01). Percentage of eyes with complete resolution of fluid at 3 and 6 months after SML were 24.3 and 21.6%, respectively. No statistically significant functional improvement (VA) could be shown. Multivariable regression and linear mixed regression analyses did not identify statistically significant differences in SRF reduction, CMT change, or VA improvement with respect to the type of CSCR or the treatment plan used (p > 0.05). CONCLUSION: The effectiveness of SML in CSCR is under continuous debate. Our study findings demonstrate structural but only little functional changes with SML. In view of the shortage of verteporfin for photodynamic therapy, SML remains an important therapeutic option for CSCR patients.

Possible retinotoxicity of long-term vardenafil treatment.

Phosphodiesterase (PDE) inhibitors - such as vardenafil - are used primarily for treating erectile dysfunction via increasing cyclic guanosine monophosphate (cGMP) levels. Recent studies have also demonstrated their significant cardioprotective effects in several diseases, including diabetes, upon long-term, continuous application. However, PDE inhibitors are not specific for PDE5 and also inhibit the retinal isoform. A sustained rise in cGMP in photoreceptors is known to be toxic; therefore, we hypothesized that long-term vardenafil treatment might result in retinotoxicity. The hypothesis was tested in a clinically relevant animal model of type 2 diabetes mellitus. Histological experiments were performed on lean and diabetic Zucker Diabetic Fatty rats. Half of the animals were treated with vardenafil for six months, and the retinal effects were evaluated. Vardenafil treatment alleviated rod outer segment degeneration but decreased rod numbers in some positions and induced changes in the interphotoreceptor matrix, even in control animals. Vardenafil treatment decreased total retinal thickness in the control and diabetic groups and reduced the number of nuclei in the outer nuclear layer. Müller cell activation was detectable even in the vardenafil-treated control animals, and vardenafil did not improve gliosis in the diabetic group. Vardenafil-treated animals showed complex retinal alterations with improvements in some parameters while deterioration in others. Our results point towards the retinotoxicity of vardenafil, even without diabetes, which raises doubts about the retinal safety of long-term continuous vardenafil administration. This effect needs to be considered when approving PDE inhibitors for alternative indications.

The Use of the RETeval Portable Electroretinography Device for Low-Cost Screening: A Mini-Review.

Electroretinography (ERG) provides crucial insights into retinal function and the integrity of the visual pathways. However, ERG assessments classically require a complicated technical background with costly equipment. In addition, the placement of corneal or conjunctival electrodes is not always tolerated by the patients, which restricts the measurement for pediatric evaluations. In this short review, we give an overview of the use of the RETeval portable ERG device (LKC Technologies, Inc., Gaithersburg, MD, USA), a modern portable ERG device that can facilitate screening for diseases involving the retina and the optic nerve. We also review its potential to provide ocular biomarkers in systemic pathologies, such as Alzheimer's disease and central nervous system alterations, within the framework of oculomics.

Correction: The assessment of fundus image quality labeling reliability among graders with different backgrounds.

[This corrects the article DOI: 10.1371/journal.pone.0271156.].

Qualitative and quantitative comparison of two semi-manual retinal vascular density analyzing methods on optical coherence tomography angiography images of healthy individuals.

The aim of this study was to evaluate qualitative and quantitative differences in vascular density analysis of an established and a novel alternative for post-processing on optical coherence tomography angiography (OCTA) images in healthy individuals. OCTA examinations of 38 subjects were performed. After extracting the images, two semi-manual post-processing techniques, the already established Mexican hat filtering (MHF) and an alternative, the Shanbhag thresholding (ST) were applied. We assessed Vessel Density (VD), Skeleton Density (SkD) and Vessel Diameter Index (VDI). We analyzed the results in order to establish similarities or potentially relevant differences. Regarding SkD and VD, MHF generally gave higher values than ST. Simultaneously, mean values were also predominantly higher by MHF; however, standard deviations (SD) were higher by ST (range [mean ± SD]: 0.054 ± 0.038 to 0.134 ± 0.01 and 0.134 ± 0.095 to 0.362 ± 0.028 vs 0.012 ± 0.014 to 0.087 ± 0.03 and 0.039 ± 0.047 to 0.4 ± 0.095 for SkD and VD with MHF vs SkD and VD with ST, respectively). Values of VDI were considerably higher with ST than with MHF, while standard deviation was still significantly higher with ST (range [mean ± SD]: 2.459 ± 0.144 to 2.71 ± 0.084 and 2.983 ± 0.929 to 5.19 ± 1.064 for VDI with MHF and ST, respectively). The noise level reduction of the two methods were almost identical (noise levels: 65.8% with MHT and 65.24% with ST). Using MHF, the vascular network gets more fragmented by an average of 40% compared to ST. Both methods allow the segmentation of the vascular network and the examination of vascular density parameters, but they produce largely inconsistent results. To determine if these inconsistent results are clinically meaningful, and which method is more suitable for clinical use, our results provide further evidence that detailed understanding of the image analysis method is essential for reliable decision making for patients with retinal pathology. For longitudinal monitoring, use of the same image processing method is recommended.

Robot-Assisted Epiretinal Membrane Peeling: A Prospective Assessment of Pre- and Intra-Operative Times and of Surgeons' Subjective Perceptions.

PURPOSE: The Preceyes Surgical System (PSS) is a robotic assistive device that may enhance surgical precision. This study assessed pre- and intra-operative times and surgeons' perceptions of robot-assisted epiretinal membrane peeling (RA-MP). METHODS: We analyzed the time requirement of three main tasks: the preparation of the PSS (I), patient preparation (II), and surgery (III). Following surgery, the surgeons were asked questions about their experience. RESULTS: RA-MP was performed in nine eyes of nine patients. Task I required an average time of 12.3 min, initially taking 15 min but decreasing to 6 min in the last surgery. Task II showed a mean time of 47.2 (range of 36-65) min. Task III had a mean time of 72.4 (range of 57-100) min. A mean time of 27.9 (range of 9-46) min was necessary for RA-MP. The responses to the questionnaire revealed a trend towards increasing ease and reduced stress as familiarity with the PSS increased. CONCLUSIONS: A substantial reduction in pre- and intra-operative times, decreasing to a total of 115 min, was demonstrated. RA-MP was positively anticipated by the surgeons and led to no hand or arm strain while being more complex than manual MP.

The Assessment of Acute Chorioretinal Changes Due to Intensive Physical Exercise in Senior Elite Athletes.

Regular physical exercise is known to lower the incidence of age-related eye diseases. We aimed to assess the acute chorioretinal alterations in older adults following intense physical strain. Seventeen senior elite athletes were recruited who underwent an aerobic exercise on a cycle ergometer and macular scanning by optical coherence tomography. A significant thinning of the entire retina was observed 1 min after exercise, followed by a thickening at 5 min, after which the thickness returned to baseline. This trend was similar in almost every single retinal layer, although a significant change was observed only in the inner retina. Choroidal thickness changes were neither significant nor did they correlate with the thickness changes of intraretinal layers. The mechanism of how these immediate retinal changes chronically impact age-related sight-threatening pathologies that, in turn, result in a substantially reduced quality of life warrants further investigation on nontrained older adults as well.

A Modification of the Inverted Internal Limiting Membrane Flap Technique without Heavy Liquids and Prone Posturing. / Eine Modifikation der inversen Membrana-limitans-interna-Lappentechnik ohne Einsatz schwerer Flüssigkeiten und Bauchlagerung.

Primary closure of large macular holes remains challenging, and variations of inverted inner limiting membrane (ILM) flap surgery have been described. In the present retrospective, interventional, single-centre case series, we propose a superior flap design with minimal posturing. Eight eyes of eight patients (four women and four men) in the period between July 2020 and March 2022 underwent 23 G three-port vitrectomy with a superior inverted ILM flap and 20% SF6 endotamponade for a full thickness macular hole (MH) by the same experienced surgeon (F. M. H.). Seven MHs were classified as large (> 400 µm) and one as medium (250 - 400 µm). The mean MLD was 638.0 ± 166.4 µm (range: 353 - 851 µm). MH closure was achieved in all (8/8, 100%) patients with a single surgery. The median best-corrected visual acuity (BCVA) improved from 6/120 (Snellen) (range: finger counting [FC] to 6/19) preoperatively to 6/19 (range: FC to 6/9.5) after surgery, without any intra- or postoperative complications. The superior inverted ILM flap technique seems to be a safe and successful approach for the primary closure of large MHs. Further studies should investigate our proposed surgical technique on a larger population, potentially without air or gas endotamponade.

Incidence of severe rise in intraocular pressure after intravitreous injection of aflibercept with prefilled syringes.

Our aim was to analyze the intraocular pressure (IOP) changes following different intravitreous injection (IVI) procedures with or without prefilled syringes (PFS) and to elaborate their possible causes. Clinical study and laboratory assessment. 173 eyes of 141 patients. The IOP was prospectively measured pre- and postoperatively in three groups of patients receiving IVI either with ranibizumab (RP), aflibercept PFS (AP) or aflibercept vials (AV). The AP emptying volume (EV) was assessed using 40 aflibercept PFS vials: the plunger was aligned precisely (normal volume, NV) or right below the indication line (high volume, HV) and the drug was ejected with (wP) or without forced pressure (nP). Primary outcome was post-treatment IOP with type of IVI and pre-treatment IOP as fixed factors. Secondary outcome was identification of possibly confounding factors (age, sex, pathology, presence of pseudophakia, spherical error, and number of injections) and IOP > 30 mmHg post-treatment. An IOP rise above 30 mmHg was observed in 8/38 (22%), 16/51 (31%) and 35/86 (41%) cases in the RP, AV and AP groups, respectively (p = 0.129). Pre-treatment IOP was the only predictive variable for IOP rise (p < 0.001). The EV values in the NVnP, NVwP, HVnP and HVwP groups were 56.06 ± 10.32, 70.69 ± 4.56, 74.22 ± 7.41 and 81.63 ± 3.67 µl, respectively (p < 0.001). We observed a marked, although not significantly higher incidence of IOP elevations with the aflibercept PFS. One possible reason may be the error-proneness of administering the correct volume with the AP. Caution should be taken when using the aflibercept PFS in order to prevent potential optic nerve damage in cases with marked elevation in IOP.

The Role of Intravitreal Corticosteroids in the Treatment of DME: Predictive OCT Biomarkers.

This work aims to summarize predictive biomarkers to guide treatment choice in DME. Intravitreal anti-VEGF is considered the gold standard treatment for centers involving DME, while intravitreal steroid treatment has been established as a second-line treatment in DME. However, more than 1/3 of the patients do not adequately respond to anti-VEGF treatment despite up to 4-weekly injections. Not surprisingly, insufficient response to anti-VEGF therapy has been linked to low-normal VEGF levels in the serum and aqueous humor. These patients may well benefit from an early switch to intravitreal steroid treatment. In these patients, morphological biomarkers visible in OCT may predict treatment response and guide treatment decisions. Namely, the presence of a large amount of retinal and choroidal hyperreflective foci, disruption of the outer retinal layers and other signs of chronicity such as intraretinal cysts extending into the outer retina and a lower choroidal vascular index are all signs suggestive of a favorable treatment response of steroids compared to anti-VEGF. This paper summarizes predictive biomarkers in DME in order to assist individual treatment decisions in DME. These markers will help to identify DME patients who may benefit from primary dexamethasone treatment or an early switch.

The assessment of fundus image quality labeling reliability among graders with different backgrounds.

PURPOSE: For the training of machine learning (ML) algorithms, correctly labeled ground truth data are inevitable. In this pilot study, we assessed the performance of graders with different backgrounds in the labeling of retinal fundus image quality. METHODS: Color fundus photographs were labeled using a Python-based tool using four image categories: excellent (E), good (G), adequate (A) and insufficient for grading (I). We enrolled 8 subjects (4 with and 4 without medical background, groups M and NM, respectively) to whom a tutorial was presented on image quality requirements. We randomly selected 200 images from a pool of 18,145 expert-labeled images (50/E, 50/G, 50/A, 50/I). The performance of the grading was timed and the agreement was assessed. An additional grading round was performed with 14 labels for a more objective analysis. RESULTS: The median time (interquartile range) for the labeling task with 4 categories was 987.8 sec (418.6) for all graders and 872.9 sec (621.0) vs. 1019.8 sec (479.5) in the M vs. NM groups, respectively. Cohen's weighted kappa showed moderate agreement (0.564) when using four categories that increased to substantial (0.637) when using only three by merging the E and G groups. By the use of 14 labels, the weighted kappa values were 0.594 and 0.667 when assigning four or three categories, respectively. CONCLUSION: Image grading with a Python-based tool seems to be a simple yet possibly efficient solution for the labeling of fundus images according to image quality that does not necessarily require medical background. Such grading can be subject to variability but could still effectively serve the robust identification of images with insufficient quality. This emphasizes the opportunity for the democratization of ML-applications among persons with both medical and non-medical background. However, simplicity of the grading system is key to successful categorization.

The assessment of acute chorioretinal changes due to intensive physical exercise in young adults.

PURPOSE: There is abundant evidence on the benefits of physical activity on cardiovascular health. However, there are only few data on the acute effects of physical exercise on the retina and choroid. Our aim was the in vivo examination of chorioretinal alterations following short intense physical activity by spectral domain optical coherence tomography (SD-OCT). METHODS: Twenty-one eyes of 21 healthy, young subjects (mean age 22.5 ± 4.1 years, 15 males and 6 females) were recruited. Macular scanning with a SD-OCT was performed before and following a vita maxima-type physical strain exercise on a rowing ergometer until complete fatigue. Follow-up OCT scans were performed 1, 5, 15, 30 and 60 minutes following the exercise. The OCT images were exported and analyzed using our custom-built OCTRIMA 3D software and the thickness of 7 retinal layers was calculated, along with semi-automated measurement of the choroidal thickness. One-way ANOVA analysis was performed followed by Dunnett post hoc test for the thickness change compared to baseline and the correlation between performance and thickness change has also been calculated. The level of significance was set at 0.001. RESULTS: We observed a significant thinning of the total retina 1 minute post-exercise (-7.3 ± 0.6 µm, p < 0.001) which was followed by a significant thickening by 5 and 15 minutes (+3.6 ± 0.6 µm and +4.0 ± 0.6 µm, respectively, both p <0.001). Post-exercise retinal thickness returned to baseline by 30 minutes. This trend was present throughout the most layers of the retina, with significant changes in the ganglion cell-inner plexiform layer complex, (-1.3 ± 0.1 µm, +0.6 ± 0.1 µm and +0.7 ± 0.1 µm, respectively, p <0.001 for all), in the inner nuclear layer at 1 and 5 minutes (-0.8 ± 0.1 µm and +0.8 ± 0.1 µm, respectively, p <0.001 for both), in the outer nuclear layer-photoreceptor inner segment complex at 5 minute (+2.3 ± 0.4 µm, p <0.001 for all) and in the interdigitation zone-retinal pigment epithelium complex at 1 and 15 minutes (-3.3 ± 0.4 µm and +1.8 ± 0.4 µm, respectively, p <0.001 for both). There was no significant change in choroidal thickness; however, we could detect a tendency towards thinning at 1, 15, and 30 minutes following exercise. The observed changes in thickness change did not correlate with performance. Similar trends were observed in both professional and amateur sportsmen (n = 15 and n = 6, respectively). The absolute changes in choroidal thickness did not show any correlation with the thickness changes of the intraretinal layers. CONCLUSIONS: Our study implies that in young adults, intense physical exercise has an acute effect on the granular layers of the retina, resulting in thinning followed by rebound thickening before normalization. We could not identify any clear correlation with either choroidal changes or performance that might explain our observations, and hence the exact mechanism warrants further clarification. We believe that a combination of vascular and mechanic changes is behind the observed trends.

Hypothetical Switch of Anti-Vascular Endothelial Growth Factor in Neovascular Age-Related Macular Degeneration: An ARIES Post Hoc Analysis.

INTRODUCTION: Switching to an alternative anti-vascular endothelial growth factor (anti-VEGF) agent has been suggested for patients with neovascular age-related macular degeneration (nAMD) who have a suboptimal response to initial therapy. However, post hoc analyses of some studies have shown that continuation of initial anti-VEGF therapy is, in many cases, associated with stable visual outcomes or gradual gains. METHODS: This ARIES (ClinicalTrials.gov Identifier: NCT02581891) post hoc analysis describes outcomes in patients with treatment-naïve nAMD receiving treat-and-extend intravitreal aflibercept (IVT-AFL) for 104 weeks, who were identified as meeting criteria for an early hypothetical switch. Patients were categorized retrospectively according to six criteria (presence of central intraretinal and/or subretinal fluid at week 8 or 24, with/without a next planned treatment interval ≤ 8 weeks, and with/without gains in best-corrected visual acuity [BCVA] ≤ 5 letters [with absolute BCVA < 70 letters]). RESULTS: Hypothetical switch criteria were largely met due to the presence of central subretinal fluid rather than intraretinal fluid. Depending on the criterion, 8-46% of patients were considered to be hypothetical switchers. BCVA outcomes were not worse in the hypothetical switchers, irrespective of criteria. Using criteria of intraretinal/subretinal fluid at week 24 and a next planned treatment interval ≤ 8 weeks, mean changes in BCVA (letters) from baseline in hypothetical switchers and non-switchers were: + 6.1 (95% confidence interval [CI] 3.4, 8.8) and + 6.6 (95% CI 4.7, 8.6), respectively, at week 24; + 8.2 (95% CI 5.0, 11.3) and + 7.5 (95% CI 5.3, 9.7), respectively, at week 52; and + 5.7 (95% CI 1.3, 10.1) and + 3.4 (95% CI 0.1, 6.7), respectively, at week 104. CONCLUSIONS: In newly diagnosed nAMD, there appears little rationale for early switching from IVT-AFL since, with continuous proactive treatment, comparable visual gains can be achieved by patients meeting hypothetical switch criteria compared with those who initially respond well on a treat-and-extend regimen. However, further prospective studies are needed. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02581891. Video summary of the ARIES Post Hoc Analysis "Hypothetical Switch of Anti-Vascular Endothelial Growth Factor in Neovascular Age-Related Macular Degeneration" (MP4 54283 KB).

Exploratory study of non-invasive, high-resolution functional macular imaging in subjects with diabetic retinopathy.

AIM: To evaluate a high-resolution functional imaging device that yields quantitative data regarding macular blood flow and capillary network features in eyes with diabetic retinopathy (DR). METHODS: Prospective, cross-sectional comparative case-series in which blood flow velocities (BFVs) and non-invasive capillary perfusion maps (nCPMs) in macular vessels were measured in patients with DR and in healthy controls using the Retinal Functional Imager (RFI) device. RESULTS: A total of 27 eyes of 21 subjects were studied [9 eyes nonproliferative diabetic retinopathy (NPDR), 9 eyes proliferative diabetic retinopathy (PDR) and 9 controls]. All diabetic patients were type 2. All patients with NPDR and 5 eyes with PDR also had diabetic macular edema (DME). The NPDR group included eyes with severe (n=3) and moderate NPDR (n=6), and were symptomatic. A significant decrease in venular BFVs was observed in the macular region of PDR eyes when compared to controls (2.61±0.6 mm/s and 2.92±0.72 mm/s in PDR and controls, respectively, P=0.019) as well as PDR eyes with DME compared to NPDR eyes (2.36±0.51 mm/s and 2.94±1.09 mm/s in PDR with DME and NPDR, respectively, P=0.01). CONCLUSION: The RFI, a non-invasive imaging tool, provides high-resolution functional imaging of the retinal microvasculature and quantitative measurement of BFVs in visually impaired DR patients. The isolated diminish venular BFVs in PDR eyes compared to healthy eyes and PDR eyes with DME in comparison to NPDR eyes may indicate the possibility of more retinal vein compromise than suspected in advanced DR.

Investigating Vascular Complexity and Neurogenic Alterations in Sectoral Regions of the Retina in Patients With Cognitive Impairment.

Evidence is accumulating that cognitive function, and visual impairment may be related. In this pilot study, we investigated whether multifractal dimension and lacunarity analyses performed in sectoral regions of the retina may reveal changes in patients with cognitive impairment (CI) that may be masked in the study considering the whole retinal branching pattern. Prospective age-matched subjects (n = 69) with and with no CI and without the presence of any ophthalmic history were recruited (age > 55+ years). The Montreal Cognitive Assessment (MoCA) was used to measure CI, and full-field electroretinogram (ERG) was performed. Also, visual performance exams were conducted using the Rabin cone contrast test (CCT). Quantification of the retinal structure was performed in retinal fundus images [45 o field of view (FOV), optic disk centered] with excellent quality for all individuals [19 healthy controls (HC) and 20 patients with CI] after evaluating the inclusion and exclusion criteria in all study participants recruited (n = 69). The skeletonized vasculature network that comprised the whole branching pattern observable in the full 45° FOV was obtained for each image and divided into nine equal regions (superotemporal, superior, superonasal, macular, optic disk, nasal, inferotemporal, inferior, and inferonasal). The multifractal behavior was analyzed by calculating the generalized dimension Dq (Do, D1, and D2), the lacunarity parameter (Λ), and singularity spectrum f(α) in the nine sectoral skeletonized images as well as in the skeletons that comprised the whole branching pattern observable in the full 45° FOV. The analyses were performed using the ImageJ program together with the FracLac plug-in. Independent sample t-tests or Mann Whitney U test and Pearson correlation coefficient were used to find associations between all parameters in both groups. The effect size (Cohen's d) of the difference between both groups was also assessed. A p-value < 0.05 was considered statistically significant. Significant correlations between multifractal and Λ parameters with the MoCA and implicit time ERG-parameter were observed in the regional analysis. In contrast, no trend was found when considering the whole retinal branching pattern. Analysis of combined structural-functional parameters in sectoral regions of the retina, instead of individual retinal biomarkers, may provide a useful clinical marker of CI.

The Effect of Physical Exercise on the Retina and Choroid.

There is only limited information available on the effects of physical exercise on the posterior pole. Retinal circulation is autoregulated similarly to the brain vasculature in order to provide constant flow and thus constant nutrition of the inner retinal structures while the choroid is mostly controlled by the sympathetic nervous system. The available data show that physical exercise may indeed have a positive effect on the retina and visual function. The assessment of retinal structure could serve as a marker in sports medicine, whereas physical activity could exert a positive protective effect against diseases such as diabetic retinopathy or age-related macular degeneration. According to our theory, similar to the term "trained heart" used in cardiology and sports medicine, the term "trained eye" could also be coined. This latter term would help to further emphasize the beneficial effects of physical exercise that works protectively not only for the cardiovascular but for the visual system as well, and thus could further help in the fight against avoidable blindness worldwide.

Distinguishing cognitive impairment by using singularity spectrum and lacunarity analysis of the retinal vascular network.

The development of effective therapies for cognitive impairment (CI), especially due to Alzheimer's disease, demands diagnosing the condition during the prodromal phase. The diagnosis of CI involves expensive and invasive methods, such as positron emission tomography and cerebrospinal fluid assessment via spinal tap. Hence, a comparatively lower cost and noninvasive method of diagnosis is imperative. The human retina is an extension of the brain characterized by similarities in vascular and neural structures. The complications of CI are not only limited to the brain but also affect the retina for which the loss of retinal ganglion cells has been associated with neurodegeneration in the brain. The loss of retinal ganglion cells in individuals with CI may be related to reduced vascular demand and a potential remodeling of the retinal vascular branching complexity. Retinal imaging biomarkers may provide a low cost and noninvasive alternative for the diagnosis of CI. In this study, the retinal vascular branching complexity of patients with CI was characterized using the singularity spectrum multifractal dimension and lacunarity parameter. A reduced vascular branching complexity was observed in subjects with CI when compared to age- and sex-matched cognitively healthy controls. Significant associations were also found between retinal vascular and functional parameters.

A Simple, Inexpensive, and Precise Photographic Method for Intraoperative Toric IOL Alignment.

BACKGROUND: It was the aim of this study to analyse the refractive outcome of toric intraocular lens (t-IOL) implantation guided by a newly developed method of photographic alignment. MATERIAL AND METHODS: Fourteen eyes of 10 patients (6 females, 4 males, age 63.4 ± 6.7 (40.6 - 68.0) years [mean ± 1 SD (range)]) were included in this retrospective study. All eyes received an Oculentis Tplus LS-313 (Oculentis, Berlin, Germany) t-IOL after standard phacoemusification (n = 4) or femtocataract laser-assisted surgery (n = 10). Image-guided t-IOL alignment included: (1) calculation of t-IOL parameters (combination of different biometric methods) and plotting a layout drawing of the target lens position, (2) capture of an anterior segment slit lamp photograph in the upright position, (3)  superposition of the photographs by the t-IOL target plot and a gradual scale, (4) drawing of marker lines on the photograph and removal of the IOL target coordinates, (5) transfer of the final image to a tablet PC, and (6) marking of the target axis at the corneal limbus with an ink pen in the surgical room. RESULTS: Preoperative corneal astigmatism was 2.50 ± 0.97 (1.38 - 4.34) diopters (D) (mean ± 1 SD, range). In all eyes, intraoperative alignment could easily be performed using the photographic target layout. Surgical interventions and postoperative follow-up were without complications in all cases. Residual postoperative astigmatism was 0.16 ± 0.24 (0.00 - 0.75) D (p < 0.001 compared to preoperative astigmatism). In 64% of patients, residual subjective astigmatism was zero, in 93% ≤ 0.5 D, and in 100% ≤ 0.75 D. Postoperative uncorrected logMAR visual acuity (0.05 ± 0.07, range 0.00 - 0.20) and best-corrected visual acuity (0.03 ± 0.05, 0.00 - 0.10) were significantly better (each p < 0.001) than best-corrected preoperative visual acuity (0.21 ± 0.14, 0.00 - 0.49). CONCLUSIONS: Results of this clinical series clearly indicate that the newly developed photographically guided technique of toric lens alignment leads to highly accurate postoperative results for astigmatic correction.

The Assessment of Blood Flow Velocities in Retinal Collaterals in Diabetic Retinopathy.

PURPOSE: Diabetic retinopathy (DR) is a microvascular disease characterized by capillary dropout and resultant retinal ischemia which then leads to retinal vascular remodeling. Our goal was to assess blood flow velocities in retinal collateral vessels in healthy and diabetic subjects with various stages of DR. METHODS: In our pilot study, we enrolled five eyes of five healthy subjects (H), five eyes of four subjects with diabetes and no retinopathy (DM), three eyes of three subjects with mild non-proliferative diabetic retinopathy (MDR), and five eyes of four subjects with proliferative diabetic retinopathy (PDR). Following routine ophthalmic examination, all subjects were imaged using a retinal function imager (RFI; Optical Imaging Inc., Rehovot, Israel). The built-in software of the RFI was used to identify and segment retinal collaterals with measurement of the blood flow velocities (BFV). One-way ANOVA was performed for BFV, followed by Newman-Keuls post hoc test. The level of significance was set at 5%. RESULTS: The total number of collateral segments involved in the study was 30, 31, 21, and 39 in the H, DM, MDR, and PDR groups, respectively. The BFVs in the collaterals were significantly lower in PDR (H: 1.86 ± 0.67, DM: 1.91 ± 0.71, MDR: 1.71 ± 0.53, PDR: 1.37 ± 0.58 mm/s). The PDR group showed a statistically significant difference in the comparisons to all groups (p = 0.012, p = 0.008, and p = 0.043 for the H, DM, and MDR groups, respectively), while no other comparisons between the groups were significant. CONCLUSION: We observed decreased BFV in retinal collaterals in PDR that may be due to the extensive capillary dropout and retinal ischemia. Further studies are needed for the noninvasive functional assessment of retinal microvascular changes in DR to better understand the underlying pathophysiology.