Reduced corneal nerve fibre length in prediabetes and type 2 diabetes: The Maastricht Study

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Ocular neurodegenerative changes and macular cysts in prediabetes and type 2 diabetes

Over the last 20 years, the number of people suffering from diabetes or prediabetes has doubled. Retinal microvascular changes (i.e. microaneurysms and haemorrhages) and neurodegenerative changes (i.e. degeneration of ganglion cells and axons) are a result of diabetes. These changes can cause vision loss, impaired dark adaptation and colour blindness. Due to diabetes, neurodegenerative changes of the corneal subbasal nerve plexus may occur as well, including reduced nerve fibre length. Therefore, diabetes is associated with delayed corneal epithelial healing, impaired corneal sensitivity and corneal erosions. This dissertation shows that neurodegenerative changes may also occur in the absence of microvascular changes. Approximately 50 percent of neuronal damage of retina, optic nerve and cornea is already present in prediabetes. Early diagnosis of and regular follow-up appointments with people with prediabetes can have a major impact on public health and public health costs

Ophthalmic artery Doppler waveform changes associated with increased damage in glaucoma patients

To characterize Doppler waveform variables (early systolic acceleration [ESA] and systolic/diastolic mean velocity ratios [Sm/Dm]) of the Ophthalmic Artery (OA) by color Doppler imaging (CDI) in eyes with primary open-angle glaucoma (POAG).status: publishe

Lack of spontaneous venous pulsation: possible risk indicator in normal tension glaucoma?

Purpose:  Recently, the absence of spontaneous venous pulsation (SVP) has been suggested as a vascular risk factor for primary open-angle glaucoma (POAG). As the mechanism behind this phenomenon is still unknown, the authors have studied this vascular component using colour Doppler imaging (CDI). Methods:  A total of 236 patients were divided into three diagnostic groups: healthy controls (81), POAG (86) and normal tension glaucoma (NTG; 69). All subjects were submitted to CDI studies of the retrobulbar circulation, intraocular pressure measurements and assessment of SVP existence. Mann-Whitney, chi-square contingency tables and Spearman correlations were used to explore differences and correlations between variables in the diagnostic groups. Results:  Eighty-two percent of healthy controls had SVP (66/81), while a smaller numbers were registered in both glaucoma groups: POAG - 50% (43/86); NTG - 51% (35/69). In NTG patients, but not in POAG patients, the prevalence of the SVP phenomenon decreases with increased glaucoma damage (p = 0.04; p = 0.55, respectively). Overall glaucoma patients from both groups had lower central retinal vein (CRV) velocities than the healthy controls (p < 0.05). NTG patients with SVP had less severe visual field defects (mean defect -6.92 versus -11.1, p < 0.05), lower peak systolic and mean flow velocities in the central retinal artery (p < 0.01; p < 0.05, respectively) as well as lower maximal velocities and RI of the CRV (p < 0.02; p < 0.05, respectively). Conclusions:  Glaucoma patients have a decrease in CRV velocities. SVP is less prevalent in glaucoma patients than in healthy individuals. This phenomenon apparently reflects different hemodynamic patterns in the central retinal vessels. This variable may be of particular importance in NTG patients, where it may be associated with more advanced functional damage.status: publishe

Diabetic retinal neurodegeneration associated with synaptic proteins and functional defects: A systematic review

Diabetic retinopathy (DR) is the most common ophthalmological complication of diabetes mellitus (DM) and a leading cause of preventable visual impairment. In DM, retinal neurodegenerative changes precede microvascular changes which can be assessed by electrophysiological and advanced imaging techniques. Studies measuring retinal neurodegenerative changes in DM were systematically evaluated in this review. Included studies have assessed retinal neurodegeneration in diabetic rodents by combining clinically used diagnostic techniques and molecular assays. Significant impairment was noticed in electrophysiology data in the diabetic retina as compared to the non-diabetic retina. Also, a significant reduction in synaptic protein levels was noticed in the diabetic retina compared to the non-diabetic retina. Even though retinal neurodegeneration was noticed, no vascular abnormalities were seen in the diabetic retina. However, little is known about molecular mechanisms behind diabetic retinal neurodegeneration (DRN), which explains the need for further investigation to detect DR in the early stages of diabetes

Short communication: unique metabolic signature of proliferative retinopathy in the tear fluid of diabetic patients with comorbidities — preliminary data for PPPM validation

Type 2 diabetes (T2DM) defined as the adult-onset type that is primarily not insulin-dependent, comprises over 95% of all diabetes mellitus (DM) cases. According to global records, 537 million adults aged 20-79 years are affected by DM that means at least 1 out of 15 persons. This number is projected to grow by 51% by the year 2045. One of the most common complications of T2DM is diabetic retinopathy (DR) with an overall prevalence over 30%. The total number of the DR-related visual impairments is on the rise, due to the growing T2DM population. Proliferative diabetic retinopathy (PDR) is the progressing DR and leading cause of preventable blindness in working-age adults. Moreover, PDR with characteristic systemic attributes including mitochondrial impairment, increased cell death and chronic inflammation, is an independent predictor of the cascading DM-complications such as ischemic stroke. Therefore, early DR is a reliable predictor appearing upstream of this “domino effect”. Global screening, leading to timely identification of DM-related complications, is insufficiently implemented by currently applied reactive medicine. A personalised predictive approach and cost-effective targeted prevention shortly - predictive, preventive and personalised medicine (PPPM / 3PM) could make a good use of the accumulated knowledge, preventing blindness and other severe DM complications. In order to reach this goal, reliable stage- and disease-specific biomarker panels are needed characterised by an easy way of the sample collection, high sensitivity and specificity of analyses. In the current study, we tested the hypothesis that non-invasively collected tear fluid is a robust source for the analysis of ocular and systemic (DM-related complications) biomarker patterns suitable for differential diagnosis of stable DR versus PDR. Here, we report the first results of the comprehensive ongoing study, in which we correlate individualised patient profiles (healthy controls versus patients with stable D as well as patients with PDR with and without co-morbidities) with their metabolic profiles in the tear fluid. Comparative mass spectrometric analysis performed has identified following metabolic clusters which are differentially expressed in the groups of comparison: acylcarnitines, amino acid &amp; related compounds, bile acids, ceramides, lysophosphatidyl-choline, nucleobases &amp; related compounds, phosphatidyl-cholines, triglycerides, cholesterol esters, and fatty acids. Our preliminary data strongly support potential clinical utility of metabolic patterns in the tear fluid indicating a unique metabolic signature characteristic for the DR stages and PDR progression. This pilot study creates a platform for validating the tear fluid biomarker patterns to stratify T2DM-patients predisposed to the PDR. Moreover, since PDR is an independent predictor of severe T2DM-related complications such as ischemic stroke, our international project aims to create an analytical prototype for the “diagnostic tree” (yes/no) applicable to healthrisk assessment in diabetes care

Bowman Layer Transplantation for Treating Keratoconus - Preliminary Findings

Background: Mid-stromal isolated Bowman layer transplantation aims to reduce and stabilize corneal ectasia in patients with advanced, progressive keratoconus. The purpose of this review is to evaluate the effectiveness and safety of this new surgical technique. Methods: Following the PRISMA statement and checklist, we searched Medline, the Cochrane Controlled Trials Register, and Embase and used a broad systematic search strategy according to the Cochrane Collaboration. Results: Eight studies with a total number of 120 eyes of 106 patients met our inclusion criteria. One month after Bowman layer transplantation, patients with keratoconus showed a significant decrease in the measured simulated keratometry (−4.74 D [95% CI −6.79 to −2.69]) and the maximum keratometry (−7.41 D [95% CI −9.64 to −5.19]), which remained significant one year postoperatively (−2.91 D [95% CI −5.29 to −0.53] and −5.80 D [−8.49 to −3.12]). Intra- and postoperative complications were observed in 3% and 9% of the patients, respectively. An estimated success rate of 75% to 85% was achieved by experienced surgeons at 5 to 8 years postoperatively. Conclusions: Bowman layer transplantation may be an effective and safe treatment option in patients with advanced, progressive keratoconus. Additional multicenter prospective interventional studies are needed to confirm these preliminary findings.</p

Comparison of Conventional and Femtosecond Laser-Assisted Cataract Surgery Regarding Macula Behavior and Thickness

Background: The aim of the study was to compare macular thickness behavior and clinical outcomes after femtosecond laser-assisted cataract surgery (FLACS) versus phacoemulsification conventional surgery (PCS). Methods: Macular Optical Coherence Tomography OCT was analyzed in 42 patients preoperatively, 1 day, 12 days, 4 weeks and 6 weeks postoperatively according to the 9-field Early Treatment Diabetic Retinopathy Study (ETDRS) grid. Clinical findings were collected in both the FLACS group and the PCS group. Results: There was no significant difference in macular thickness between the FLACS and PCS groups (p > 0.05). However, from postoperative day 12 onwards, there was a significant increase in macular thickness observed in both groups (p p = 0.006). Conclusions: The use of a low-energy high-frequency femtosecond laser has potentially no effect on postoperative macular thickness. In the FLACS group, visual rehabilitation was significantly faster as compared to the PCS group. No complications occurred intraoperatively in either group

Glucose metabolism status is associated with changes in macular thickness

Design: Cross-sectional population-based cohort study. Purpose: Macular thinning may be an early sign of diabetic retinopathy. We therefore evaluated to what extent macular thickness differed between individuals with prediabetes (preDM2) and individuals with type 2 diabetes (DM2) without cysts compared with individuals with a normal glucose metabolism (NGM). Methods: Using SD-OCT we measured macular thickness in five ETDRS subfields in 2385 participants (mean age 59 ± 8 years, 50% men, 1397 NGM, 357 preDM2, 631 DM2). Results: After adjustment for age, sex, and spherical equivalent, individuals with preDM2 showed a significant decrease in pericentral superior macular thickness compared with individuals with NGM (-3.34 ± 1.28 µm, P&lt;0.01). In individuals with DM2 without cysts, the four pericentral quadrants were significantly thinner compared with individuals with NGM (range: -5.42 ± 1.04 µm to -5.91 ± 1.03 µm, P&lt;0.001). There was a significant linear trend of pericentral macular thinning with severity of glucose metabolism status (P&lt;0.001). Conclusions: This study demonstrates that the pericentral macular thickness decreases with worsening of glucose metabolism. This may reflect early neurodegenerative changes