Limbal reconstruction in uveitic glaucoma patient with exposed Ahmed valve coincident with corneal melting and iris prolapse using multiple corneoscleral allografts.

Aim: To present a complex case of Ahmed tube exposure 6 months after the implantation associated with corneal melting and iris prolapse, and the surgical reposition that required multiple allografts and limbal reconstruction. Methods: A 60-year-old patient arrived at the emergency room with tube exposure combined with corneal melting and iris prolapse from a previously placed Ahmed valve 6 months prior. Our approach was to use one corneoscleral graft to repair the melted cornea and avoid further iris prolapse and a second scleral graft to cover the repositioned tube. Upon completion of conjunctival dissection, cleaning and deepithelization of the melted cornea and the tube by application of alcohol 100% followed. A new entry point was made for the tube and was covered using an alcohol-preserved scleral allograft and the previous entry point was repaired using a corneoscleral allograft with the corneal aspect restoring the limbus and avoiding further iris protrusion. Results: 6 months follow-up of the patient showed excellent recovery, anatomical restoration, and IOP normalization. Conclusion: Surgical repair of these cases can be very demanding, and requires surgical improvisation and prolonged surgical time. The literature remains very limited on how a surgeon should approach similar cases, which are the crucial tips, and which are the missteps that should be avoided. In this case, we used multiple scleral/corneoscleral allografts in a specific orientation and different sutures to reconstruct the damaged limbal area and restore the anatomy. Abbreviations: VA = Visual Acuity, GDD = Glaucoma Drainage Device, IOP = Intra Ocular Pressure.

Optical Coherence Tomography Angiography Changes in Patients Diagnosed With Acute Coronary Syndrome: A Systematic Review and Meta-Analysis.

We conducted a systematic review and meta-analysis to assess the association between optical coherence tomography angiography (OCTA) parameters and acute coronary syndrome (ACS). Two independent reviewers searched the electronic databases (MEDLINE (Medical Literature Analysis and Retrieval System Online), Scopus, Embase (Excerpta Medica Database), Cochrane Library, ClinicalTrials.gov, and World Health Organization International Clinical Trials Registry Platform) from inception until April 2023. According to the inclusion criteria of this review, eligible were observational studies, randomized control trials, and registry/database studies that included the eyes of adult ACS patients and assessed OCTA parameters within the macula. The pooled standardized mean differences (SMD) between patients diagnosed with ACS and healthy controls with a confidence interval (CI) of 95% were calculated using the Hartung-Knapp-Sidik-Jonkman random-effects method. The heterogeneity was assessed by I2 and the Cochran Q and a random effects model was applied. Seven studies were eligible and included in our systematic review (n = 898), of which three were included in the meta-analysis (n = 341). The pooled SMD in the superficial vascular plexus (SVP), deep vascular plexus (DVP), and foveal avascular zone (FAZ) were -0.46 (95% CI: -0.94 to 0.01, p = 0.05, I2 = 0%, three studies), -0.10 (95% CI: -3.20 to 3.00, p = 0.75, I2 = 67%, two studies), and 0.43 (95% CI: -1.22 to 2.09, p = 0.38, I2 = 92%, three studies), respectively. Our findings suggest that there are no differences in OCTA metrics between ACS patients and healthy individuals.

Retinal Nerve Fiber Layer Changes in Patients With Chronic Obstructive Pulmonary Disease Compared to Healthy Controls: A Meta-analysis.

BACKGROUND AND OBJECTIVE: This study investigated changes in retinal nerve fiber layers (RNFL) in patients diagnosed with chronic obstructive pulmonary disease (COPD) compared to healthy control patients, using optical coherence tomography. METHODS: PubMed, Cochrane Library, and Google Scholar databases were systematically searched for published articles comparing RNFL between patients with COPD and healthy controls. Standardized mean difference (SMD) with 95% confidence interval (CI) was computed to compare continuous variables. RESULTS: Average RNFL thickness was significantly reduced in COPD patients compared to healthy controls (SMD = -0.31, 95% CI = -0.48 to -0.14, P = 0.0004, I2 = 0%). Average RNFL thickness did not differ significantly between patients with mild/moderate COPD and healthy controls (SMD = -0.17, 95% CI = -0.39 to 0.04, P = 0.12, I2 = 2%), while a statistically significant reduction in average RNFL thickness was noticed in patients with severe COPD compared to healthy controls (SMD = -0.72, 95% CI = -1.23 to -0.21, P = 0.006, I2 = 83%). Average RNFL thickness was significantly higher in patients with mild/moderate COPD compared to patients with severe COPD (SMD = 0.69, 95% CI = 0.29 to 1.09, P = 0.0008, I2 = 66%). CONCLUSIONS: This meta-analysis showed that RNFL thickness was decreased in patients with COPD compared to healthy controls. Patients diagnosed with severe COPD seem to be more affected and have thinner RNFL. [Ophthalmic Surg Lasers Imaging Retina 2024;55:XX-XX.].

Screening for multifocal intraocular lens implantation in cataract patients in a public hospital.

PURPOSE: To identify the rate and characteristics of cataract surgery candidates suitable for multifocal intraocular lens implantation among patients undergoing preoperative evaluation in a public hospital. MATERIALS AND METHODS: Screening was performed based on the patient's medical records, comprehensive ophthalmic examination, optical biometry (Zeiss, IOL Master 700) and optical coherence tomography (OCT) (Heidelberg, OCT Spectralis) in accordance with the relevant indications and contraindications mentioned in the pertinent literature. Patients were included in the present study if they were eligible for bilateral cataract surgery. The exclusion criteria were the presence of central nervous system or motility issues, prior refractive surgery, the presence of astigmatism greater than 1 dioptre and/or the presence of important ocular comorbidities in either eye. RESULTS: The study evaluated 1200 consecutive patients. Four hundred thirty-two patients (36%) were not eligible for bilateral surgery and were excluded from the study. Of the 768 patients included in the present study, 346 (45.1%) were considered suitable candidates. Four hundred twenty-two patients (54.9%) were excluded for one or both eyes. Among them, 121 (28.7%) were excluded because of retinal disease, 120 (28.4%) because of regular astigmatism (> 1.0 D of corneal astigmatism), 32 (7.5%) because of pseudoexfoliation or zonular instability, and 30 (7.1%) because of glaucoma or ocular hypertension; in addition, 90 (21.3%) patients were excluded for multiple reasons. Suitable candidates were significantly younger (70 and 75 years, respectively) (p < 0.001). After being informed about the potential risks and benefits of MOIL implantation, 212 of 346 (83.8%) eligible patients provided consent. CONCLUSION: Close to half of cataract patients in a public hospital were eligible for MOIL implantation, and the majority of patients would proceed to surgery. The most prevalent contraindication was macular disease.

UGH Syndrome Resolution after IOL Explantation and Concomitant Carlevale IOL Implantation.

OBJECTIVE: To examine the use of Carlevale IOL placement in patients with UGH, and to evaluate surgical outcomes. DESIGN: In this retrospective study, 28 patients with UGH syndrome that were subjected to IOL explantation and concomitant Carlevale IOL implantation were included in the study. METHODS: Information about VA, IOP, number of glaucoma medication, need for glaucoma surgery, presence of hemorrhage and inflammation were recorded up to 6 months after the procedure. RESULTS: We found a statistically significant increase in mean visual acuity and complete resolution of uveitis in all patients. Mean IOP and the mean number of glaucoma medications were significantly decreased postoperatively, while 14% of patients required additional glaucoma surgery. CONCLUSIONS: IOL explantation and concomitant Carlevale IOL implantation may provide a viable solution for UGH syndrome resolution, increases visual acuity, and decreases the need for glaucoma medication.

Optical Coherence Tomography Angiography Changes in Macular Area in Patients with Proliferative Diabetic Retinopathy Treated with Panretinal Photocoagulation.

BACKGROUND: The purpose of this study was to investigate the changes in macular microvasculature using optical coherence tomography angiography (OCTA) in association with functional changes in patients with proliferative diabetic retinopathy (PDR) treated with panretinal photocoagulation (PRP) with a follow up of 12 months. METHODS: The participants in this study were 28 patients with PDR and no macular oedema, who were eligible for PRP. All participants underwent best-corrected visual acuity (BCVA) measurement, optical coherence tomography (OCT), and OCT angiography (OCTA) at baseline (before treatment) and at months 1, 6, and 12 after the completion of PRP treatment. The comparison of OCTA parameters and BCVA between baseline and months 1, 6, and 12 after PRP was performed. RESULTS: There was a statistically significant decrease in foveal avascular zone (FAZ) area at months 6 and 12 of the follow-up period compared to baseline (p = 0.014 and p = 0.011 for month 6 and 12, respectively). Of note is that FAZ became significantly more circular 6 months after PRP (p = 0.009), and remained so at month 12 (p = 0.015). There was a significant increase in the mean foveal and parafoveal vessel density (VD) at all quadrants at the superficial capillary plexus (SCP) at month 6 and month 12 after PRP compared to baseline. No difference was noticed in VD at the deep capillary plexus (DCP) at any time-point of the follow up. BCVA remained the same throughout the follow-up period. CONCLUSIONS: At months 6 and 12 after PRP, foveal and parafoveal VD at SCP significantly increased compared to baseline, while the FAZ area significantly decreased and FAZ became more circular.

Combining Perfluorobutylpentane (F4H5) with Glaucoma Drainage Device Implantation for Silicone Oil-Induced Glaucoma: A Pilot Study.

Objectives: Our aim was to perform a perfluorobutylpentane (F4H5) washout in conjunction with glaucoma drainage device (GDD) placement in patients with silicone oil (SO)-induced glaucoma. In this report we present our preliminary results concerning the effectiveness in clearing the SO and the safety of the procedure. Materials and Methods: Eight patients who previously underwent pars plana vitrectomy with SO tamponade due to retinal detachment were selected. Removal of SO was performed on average 10 months after initial surgery. All patients developed glaucoma with evidence of SO remnants in the anterior chamber (AC) and angle. Removal of the remaining SO with F4H5 washout was performed in all cases with concomitant insertion of a GDD to treat the refractory glaucoma. Intraocular pressure (IOP), SO remnants, endothelial cell count, and need for glaucoma medications were evaluated up to 12 months after the surgical procedure. Results: All patients had uneventful surgery with no major complications 12 months postoperatively. A marked reduction of SO remnants in the AC and angle was observed in all cases after surgery. There was a 60.9% decrease in mean IOP 12 months postoperatively (p<0.05) and the need for glaucoma medication was lower in all patients (mean topical medicines: 4 preoperatively vs. 0.75±0.89 postoperatively; p<0.05). Endothelial cell density showed no significant change (mean 2012±129 cells/mm2 preoperatively vs. 1985±134 cells/mm2 postoperatively; p>0.05), and there were no signs of corneal edema. Conclusion: F4H5 is an effective emulsifier for removing SO remnants and may be safely used in conjunction with GDD placement in order to control IOP in eyes with silicone oil-induced glaucoma.

COMfort Eye Trial (COMET) results - a non-inferiority, randomized, investigator-masked, two-parallel group, phase III clinical trial, to evaluate the efficacy and safety of a preservative free formulation of latanoprost versus a reference drug (Xalatan®) in patients with primary open-angle glaucoma (POAG) or ocular hypertension (OHT).

AIM: To prove non-inferiority of preservative-free (PF) latanoprost versus benzalkonium chloride (BAK) containing latanoprost in lowering intraocular pressure (IOP) in primary open-angle glaucoma (POAG) or ocular hypertension (OHT) patients. DESIGN AND METHODS: This phase III, randomized, investigator-masked trial primarily aimed to demonstrate non-inferiority of YSLT PF latanoprost 50 µg/ml (Yonsung GmbH) to latanoprost (Xalatan®) 50 µg/ml (Pfizer) in reducing IOP from Baseline to Week 12. Secondary aims included conjunctival hyperemia evaluation and difference in ocular comfort levels. Total 130 patients with POAG or OHT were enrolled and randomized (1:1 ratio) to receive YSLT or latanoprost, instilling eye drops daily for 12 weeks. RESULTS: At Week 12, mean diurnal IOP reduction was -7.67 ± 2.104 mmHg for YSLT PF latanoprost and -7.77 ± 2.500 for latanoprost. The 97.5% confidence interval of between-treatment group difference in IOP reduction from Baseline to Week 12 was [-0.846, +∞), not crossing the non-inferiority margin of -1.5 mmHg. A low incidence of mild topical treatment emergent adverse events (TEAEs) was observed in both groups, while no serious TEAEs were reported. CONCLUSIONS: YSLT eye drops demonstrated non-inferiority to latanoprost in reducing IOP. Both products were well tolerated without serious TEAEs reported.

Correlation Between Coronary and Retinal Microangiopathy in Patients With STEMI.

Purpose: To investigate the morphological and functional correlation between microvascular retinal changes in optical coherence tomography angiography (OCTA) and the microvascular coronary circulation in patients with ST elevation myocardial infarction (STEMI) coronary heart disease (CHD). Methods: A total of 330 eyes from 165 participants (88 cases and 77 controls) were enrolled and imaged. Superficial capillary plexus (SCP) and deep capillary plexus (DCP) vascular density was measured in the central (1 mm) and perifoveal (1-3 mm) areas and in the superficial foveal avascular zone (FAZ) and choriocapillaris (3 mm). These parameters were then correlated to the left ventricular ejection fraction (LVEF), and the number of affected coronary arteries. Results: Decreased vessel densities in the SCP and DCP and choriocapillaris were positively correlated to the LVEF values (P = 0.006, P = 0.026, and P = 0.002, respectively). No statistically significant correlation between the SCP and DCP central area or FAZ area was found. Regarding the number of affected vessels, significant negative correlations were revealed for the SCP and DCP central vessel densities (P < 0.001 and P < 0.001, respectively) and the SCP perifoveal vascular density (P = 0.009). Conclusions: OCTA vascular indices are significantly correlated with morphological and functional parameters in patients with STEMI CHD. SCP vascular density especially seems to be a promising biomarker for the extent of both macrovascular damage (number of affected coronary arteries) and microvascular damage, as mirrored in the decreased LVEF at admission. Translational Relevance: OCTA vascular indices offer a valuable insight into the microvascular status of coronary circulation.

Effect of silicone oil on retinal microcirculation after vitrectomy for rhegmatogenous retinal detachment evaluated by OCT angiography: a literature review.

Silicone oil (SO) has been widely used as intravitreal tamponade agent for rhegmatogenous retinal detachment (RRD) and has been occasionally associated with incomplete retinal structural and functional recovery. The use of Optical Coherence Tomography Angiography (OCT-A) has recently attracted significant attention for detailed analysis of retinal capillary plexus and blood flow changes as predicting factors for postoperative outcomes. A detailed literature search was performed in PubMed database until October 2022. The following keywords were used: rhegmatogenous retinal detachment, silicone oil, optical coherence tomography angiography, macular microvasculature, peripapillary capillary plexus, vessel density, and foveal avascular zone. We identified and reviewed 19 studies referring to microcirculation alterations of the retinal capillary plexus as seen on OCT-A in eyes treated by vitrectomy with intravitreal SO for RRD. A comprehensive update revealed variability of microcirculation characteristics of the retinal capillary plexus including the macular and the peripapillary capillaries. Further studies are warranted to clarify the OCT-A values in an attempt to identify the potential effect of SO on retinal tissue in clinical practice. A review of the existing literature sheds light on the effect of SO on retinal capillary plexus and the potential impact on functional outcomes after vitrectomy for RRD. This article discusses important aspects of key publications on the topic, highlights the importance to identify distinct alterations of the microvasculature status, and proposes the need for further future research in this field.

The Effect of Statins on Ocular Disorders: A Systematic Review of Randomized Controlled Trials.

AIM: Statins have been established in the market not only due to their ability to lower plasma cholesterol levels but also due to their pleiotropic effects. In the literature, there is a controversy regarding the role of statins in ophthalmology. We aimed to systematically address the possible effect of statin therapy on ocular diseases and to identify if there is a beneficial relationship. METHODS: We searched PubMed and Cochrane Library databases up to 31 December 2022 for studies evaluating the effect of statins on ocular diseases. We included all relevant Randomized Control Trials (RCTs) that have been conducted in the adult population. PROSPERO registration number: CRD42022364328. RESULTS: Nineteen RCTs were finally considered eligible for this systematic review, with a total of 28,940 participants. Ten studies investigated the role of simvastatin, suggesting a lack of cataractogenic effect and a possible protective role in cataract formation, retinal vascular diseases, and especially diabetic retinopathy, age-related macular disease progression, and non-infectious uveitis. Four studies investigated lovastatin, showing no cataractogenic effect. Three studies examined atorvastatin, revealing conflicting results regarding diabetic retinopathy. Two studies examined rosuvastatin, indicating a possibly harmful effect on lenses and a significant protective effect on retinal microvasculature. CONCLUSIONS: Based on our findings, we believe that statins have no cataractogenic effect. There are indications that statins may have a protective role against cataract formation, AMD, diabetic retinopathy progression, and non-infectious uveitis. However, our results were insufficient for any robust conclusion. Future RCTs, with large sample sizes, on the current topic are therefore recommended to provide more solid evidence.

Late-onset Relapse of Aqueous Misdirection after Pars Plana Vitrectomy: Case Report and Literature Review.

Aim: We report on an 88-year-old female patient who presented with a relapse in aqueous misdirection 15 years after being treated with pars plana vitrectomy (PPV) with hyaloidotomy-zonulectomy-iridotomy (HZI) for the same cause. Case description: A 73-year-old pseudophakic woman with a history of pseudoexfoliation underwent a trabeculectomy in the left eye in our institution because of uncontrolled intraocular pressure. Days after trabeculectomy, the patient developed aqueous misdirection and was treated with PPV combined with HZI. In the following years, the patient had regular follow-up appointments in our instruction, and she had normal intraocular pressures in the left eye without any treatment. A total of 15 years after the vitrectomy, the patient developed gradual swallowing in the anterior chamber and increased intraocular pressure. Neodymium (Nd): yttrium aluminum garnet (YAG) laser hyaloidotomy through the iridectomy opening was performed, the anterior chamber was immediately deepened, and the intraocular pressure was reduced to normal limits. The anterior chamber remained deep, and the intraocular pressure remained normal through the 36 months of follow-up. Conclusion: Relapse of aqueous misdirection may occur many years after vitrectomy, even when HZI is performed. An Nd: YAG- laser hyaloidotomy should be attempted before a second HZI is considered. Clinical relevance: A close and long-lasting follow-up of patients with aqueous misdirection is warranted, especially if the patients are treated not with complete PPV but by a limited disruption of the anterior hyaloid face along with HIZ. How to cite this article: Halkiadakis I, Tzimis V, Markopoulos I, et al. Late-onset Relapse of Aqueous Misdirection after Pars Plana Vitrectomy: Case Report and Literature Review. J Curr Glaucoma Pract 2023;17(1):49-51.

Unilateral hypertensive choroidopathy as a sole manifestation in malignant hypertension: optical coherence tomography angiography findings-case report.

BACKGROUND: We present a case of hypertensive choroidopathy due to malignant hypertension with exudative retinal detachment as a sole finding. We use OCT- angiography for initial diagnosis and report findings from extensive follow up. CASE PRESENTATION: A 51-year-old female with no past medical history, presented to our clinic with painless loss of vision in her left eye. Fundus examination revealed only exudative retinal detachment in her left eye that was confirmed with Optical Coherence Tomography. Fluorescein angiography showed hyperfluorescent spots with leakage in late phases. OCTA manifested a focal dark area in the choriocapillaris slab corresponding to flow signal voids, signifying regions of non-perfusion. Her blood pressure was 220/120 mmHG. Complete blood work -up failed to reveal any other possible etiology. During follow-up period of 9 months blood pressure normalized, patient regained visual function and choriocapillaris perfusion was completely restored. DISCUSSIONS AND CONCLUSIONS: Hypertensive choroidopathy with exudative retinal detachment can be the only sign of malignant hypertension and no pre-existing history of a systemic disease is required in order to become apparent. OCTA reveals areas of non-perfusion at choriocapillaris level, proving that it is an essential tool in the diagnosis and follow up of patients with hypertensive choroidopathy. Finally, we propose that early diagnosis prevents permanent damage of the RPE and leads to complete choroidal remodeling and better visual outcomes.

A closed-loop audit of the prescription practice of topical antibiotics for acute infective conjunctivitis.

Objective: The implementation of guideline recommendations for antibiotics prescription for the management of patients with acute infective conjunctivitis (AIC) in primary care departments remains below par. Our objective was to assess the impact of clinical audit on adherence to evidence-based indications for prescription of antibiotic eye drops in patients diagnosed with AIC, in the setting of a primary care practice in western Greece. Methods: We conducted a retrospective audit to evaluate the current prescription practice of antibiotics for the management of AIC. Following evidence-based indications for the prescription of antibiotics in AIC through literature search, and in combination with discussion and collaboration with the primary care doctors of our department, we formulated and implemented guidelines for the management of AIC. We then performed a prospective re-audit to assess the management of patients with AIC after local implementation of the guidelines. Results: A total of 158 cases were audited in the first cycle before the introduction of the guidelines, from 15th June 2019 to 7th March 2020, and 26 cases after, from 10th March 2020 to 20th November 2020. The compliance with the guidelines regarding antibiotics prescription was significantly improved from 12.0% to 84.6% between the first and the second cycles of audit. Conclusions: In this study, with the local introduction of guidelines, clinical audit significantly improved the prescription practice of topical antibiotics in patients with AIC in a primary care department. Abbreviations: AIC = acute infective conjunctivitis.

Spotlight on Digital Eye Strain.

Digital Eye Strain (DES) is a clinical syndrome manifested with visual disturbances and/or ophthalmic dysfunction related to the usage of screen-enabled digital equipment. This term is gradually replacing the older term computer vision syndrome (CVS) that focused on the same symptoms found on personal computer users. DES is encountered more frequently during the past years due to the explosive increase in the usage of digital devices and subsequent increase in time in front of any screens. It presents with a series of atypical symptoms and signs stemming from asthenopia, dry eye syndrome, preexisting untreated vision issues and poor screen ergonomics. This review summarizes research data to date to determine whether the concept of DES has been conclusively defined and demarcated as a separate entity and if sufficient guidance is offered on professionals and the lay public. The maturity of the field, grouping of symptoms, examination techniques, treatment and prevention modalities are summarily presented.

The Multifarious Effects of Various Glaucoma Pharmacotherapy on Corneal Endothelium: A Narrative Review.

Corneal endothelium is a single cell layer that is mainly responsible for maintaining corneal clarity. Endothelial damage secondary to toxicity, stress, or genetic predisposition are common and in conjunction with the low regenerative ability of the cells, making their preservation critical for maintaining visual acuity. Patients with glaucoma, who are estimated to be close to 80 million worldwide, have a plethora of reasons for developing endothelial damage, being exposed to a spectrum that extends from various medical and surgical interventions to the disease itself. The wide spectrum of glaucoma pharmacotherapy that has been recently extended by addition of newer classes of medications has been the focus of extensive research on its effects on corneal endothelium. Both basic and clinical research have attempted to shine a light on the complex mechanisms associated with the effects of glaucoma medication on corneal endothelium and to answer the important question as to whether these findings are clinically significant. The aim of this review is to summarize and present current literature of the various findings, both from in vivo and in vitro studies that have focused on the complex relationship between different classes of glaucoma medication and their effect on corneal endothelium.

The Effect of the Water Drinking Test on Ocular Parameters and Choroidal Thickness in Glaucoma Suspects.

Background and objectives: We aimed to evaluate the effects of the water drinking test (WDT) on several systemic and ocular parameters, including choroidal thickness, which was assessed through optical coherence tomography angiography (OCTA), in glaucoma suspects. Materials and Methods: A total of 40 eyes from 20 glaucoma suspects without any systemic or ocular diseases were included in this prospective observational study. All the participants undertook the WDT, which required the drinking of 1 L of table water in 5 min. The outcome measures included IOP, systolic and diastolic blood pressure (SBP and DBP), mean arterial pressure (MAP), mean ocular perfusion pressure (MOPP), ocular pulse amplitude (OPA), and subfoveal and peripapillary choroidal thickness, which were assessed at baseline and at four 15 min intervals after the WDT. Generalized least squares models and mixed model analyses that take into account repeated measurements were used to assess the changes over time of these parameters. Results: All the ocular and systemic parameters showed statistically significant changes at all time points compared to baseline apart from choroidal thickness. The peak changes were an IOP of 20.1 mmHg versus 17.3 mmHg at 45 min, an SBP of 137.6 mmHg versus 125 mmHg at 30 min, a DBP of 95.9 mmHg versus 85.7 mmHg at 15 min, and an MOP of 53.51 mmHg versus 48.89 mmHg at 15 min. Conclusions: Despite elevations in IOP and significant changes in all the assessed systemic parameters, the WDT was not associated with changes in choroidal thickness in glaucoma suspects.

Optical coherence tomography angiography in Parkinson's disease: a systematic review and meta-analysis.

BACKGROUND: To examine the association between optical coherence tomography angiography (OCTA) retinal measurements and Parkinson's disease (PD). METHODS: We searched MEDLINE and EMBASE from inception up to November 5th, 2021 for studies examining the differences between OCTA retinal measurements in PD patients and healthy controls. We used the Hartung-Knapp-Sidik-Jonkman random-effects method to combine study-specific standardized mean differences (SMD) in pooled effect estimates and a meta-analytic extension of the E-value metric to quantify the confounding bias capable of nullifying the pooled estimates. RESULTS: Nine eligible studies for our systematic review were identified through our search strategy. The pooled SMD between the retinal vessel density of PD patients and healthy participants in the whole superficial vascular plexus (SVP), foveal SVP, parafoveal SVP and foveal avascular zone (FAZ) was -0.68 (95% CI: -1.18 to -0.17, p value = 0.02, n = 7 studies), -0.14 (95% CI: -0.88 to 0.59, p value = 0.62, n = 5 studies), -0.59 (95% CI: -1.41 to 0.23, p value = 0.12, n = 5 studies) and -0.20 (95% CI: -0.79 to 0.38, p value = 0.39, n = 5 studies), respectively. An unmeasured confounder would need to be associated with a 3.01-fold, 1.54-fold, 2.81-fold and 1.70-fold increase in the risk of PD and OCTA retinal measurements, in order for the pooled SMD estimate of vessel density in whole SVP, parafoveal SVP and FAZ, respectively, to be nullified. CONCLUSIONS: Our results provide evidence on an inverse association between whole SVP vessel density and PD.