Correlation of retinal vascular perfusion density with dark adaptation in diabetic retinopathy.

PURPOSE: To evaluate the anatomic versus functional changes in diabetic retinopathy (DR) by studying the correlation of retinal vascular perfusion density and dark adaptation (DA). METHODS: Optical coherence tomography angiography (OCTA) and DA tests were performed in diabetic patients and nondiabetic controls. DA was measured using AdaptDx dark adaptometer and the rod intercept was recorded. Macular OCTA images were acquired using the RTVue XR Avanti with AngioVue. RESULTS: Eighty-six eyes from 57 patients with diabetes (19 with no DR, 19 with non-proliferative DR [NPDR], and 19 with proliferative DR [PDR] who had undergone photocoagulation) and 10 eyes from 10 patients without diabetes were recruited. A significant decrease in vascular density and a prolonged rod intercept were found as DR progressed (P < .01). A negative trend was found between vascular density and the rod intercept. The negative trend in the deep layer (R2 = 0.28) was more substantial than that in the superficial layer (R2 = 0.14). A prolonged rod intercept was associated with elevated HbA1c (R2 = 0.08). CONCLUSIONS: The vascular density of the macula could be assessed by OCTA and the functional change in the outer retina could be measured non-invasively by DA. The severity of decreasing vascular density and prolongation of DA are proportional to progression of DR. Decreased deep retinal vascular perfusion density and impaired DA response are correlated and show a negative trend according to the severity of DR.

Management of complications of sutureless intrascleral intraocular lens fixation.

PURPOSE: The purpose of the study was to report the complications of sutureless intrascleral (SIS) intraocular lens (IOL) fixation and its management. MATERIALS AND METHODS: A multicenter, retrospective, consecutive interventional case series of patients with intra or postoperative complications after SIS IOL fixation during the technical learning curve of vitreoretinal surgeons from three Taiwanese referral hospitals. The used surgical techniques were the Scharioth technique for intrascleral tunnel fixation, Yamane technique (double-needle scleral fixation), and modified Yamane technique (double-needle flanged haptic scleral fixation). The IOL models and surgical instruments used as well as each patient's ocular characteristics and complication management were recorded. RESULTS: Of the eight included patients, the complications of 3 (37.5%) and 5 (62.5%) were noted intraoperatively and postoperatively, respectively. Haptic-related complications, including haptic breakage, slippage, and haptic disinsertion, occurred in six eyes. Other complications included uveitis-glaucoma-hyphema syndrome, retinal detachment, and IOL tilt. For the two patients with haptic slippage, repositioning was achieved using a modified cow-hitch technique that resulted in favorable IOL centration and restored visual acuity. CONCLUSION: Most complications surgeons encountered during their early exposure to SIS IOL fixation were haptic related. Surgeons should be aware of such complications to prevent and manage them during surgery. Our modified cow-hitch technique could be used to reposition IOLs with unilateral haptic slippage.

Image processing and quantification analysis for optical coherence tomography angiography in epiretinal membrane.

BACKGROUND: To explore image processing methods for optical coherence tomography angiography (OCTA) of the epiretinal membrane (ERM), and to evaluate the impact of ERM on vision by analyzing the retinal vasculature. METHODS: Thirty eyes of 30 patients with idiopathic ERM who underwent OCTA were retrospectively evaluated. Image processing of OCTA, including the Mexican hat filter (MHF) and exclusion of the foveal avascular zone (FAZ), was attempted using Fiji. OCTA parameters, including vessel density (VD), fractal dimension (FD), and vessel tortuosity (VT), were measured for large vessels only, capillaries only, and the whole vasculature. Pearson correlation analysis was used to evaluate the correlations between best-corrected visual acuity (BCVA) and OCTA parameters. RESULTS: The correlations between BCVA and retinal vasculature were much increased when the capillaries only instead of the whole vasculature was used for analysis. Both higher VD and FD of capillaries were correlated with better BCVA, and MHF largely increased their correlations (P < 0.0001 for both). In contrast, both higher VD and FD of the large vessels were associated with poorer BCVA (P = 0.042 and 0.049, respectively). A higher VT of capillaries was correlated with better BCVA, and both MHF and exclusion of the FAZ were necessary to reveal their correlations (P = 0.028) CONCLUSIONS: Separation of large vessels and capillaries was necessary to reveal the correlations between retinal vasculature and BCVA in ERM. MHF was necessary to elucidate all microvascular parameters of capillaries, and exclusion of the FAZ was mandatory for evaluation of VT.

Corneal structural alterations in autism spectrum disorder: An in vivo confocal microscopy study.

Individuals with autism spectrum disorder (ASD) often exhibit joint hypermobility and connective tissue disorders. However, it remains unclear if ASD individuals also have structural alterations in the connective tissue of the cornea. This study aims to determine whether the Kobayashi structure (K-structure) characteristics differ between adults with ASD and typically developing controls (TDC) and explore the clinical correlates of the K-structure abnormality. We recruited 30 ASD adults and 35 TDC. Corneal structures, particularly the K-structure in the Bowman's layer, of the participants were examined using in vivo confocal microscopy (IVCM), and a K-grading ranging from 1 to 4 was given to each eye based on the level of morphological mosaicism. The ASD participants' eyes received a significantly higher single-eye K-grading than that of the TDC eyes (p < 0.001), and the medians [25th, 75th percentile] of bilateral-eye summed K-grading were 8 [7, 8] and 5 [4, 6] in ASD and TDC, respectively (p < 0.001). A significantly higher K-grading in the ASD participants' eyes was still observed after adjusting for the within-subject inter-eye correlation (p < 0.001). Youden Index showed the optimal cutoffs to differentiate ASD from TDC by bilateral-eye summed K-grading and single-eye K-grading was >6 and >3, respectively. Additionally, a higher K-grading was associated with fewer visual sensation seeking in ASD (Spearman's correlation coefficient ρ = -0.518, p = 0.008) and low visual registration (i.e., higher sensory threshold) in TDC (ρ = 0.446, p = 0.023). This study provided novel evidence of corneal structural alterations in ASD by IVCM. Our findings may not only support the prior hypothesis of the association between ASD and connective tissue abnormalities but also shed light on the relationship between connective tissue disorder and neurodevelopmental disorders.

The Changes in Optic Nerve after Orbital Decompression Surgery for Thyroid Eye Disease and Case Reports of Ischemic Optic Neuropathy.

Purpose: To demonstrate the changes in the retinal nerve fiber layer (RNFL) after orbital decompression for thyroid eye disease (TED). Methods: We retrospectively enrolled 52 surgical TED patients, 30 nonsurgical TED patients, and 30 control subjects. Five surgical TED eyes with disc edema were excluded. The surgical TED patients were classified into the "dysthyroid optic neuropathy (DON)" group (16 eyes) and the "non-DON" group (83 eyes). Optical coherence tomography (OCT) and visual field (VF) examinations were performed preoperatively and 6 months later. The control subjects and nonsurgical TED patients received two OCT examinations at 6-month intervals. The postoperative changes in the RNFL thickness were compared between groups. Three cases with severe postoperative vision loss were presented additionally. Results: The changes in the RNFL thickness of the controls (0.5 ± 3.4 µm) and the nonsurgical TED patients (0.3 ± 2.8 µm) were significantly smaller than the surgical TED patients (P < 0.001). The DON group (-9.2 ± 9.2 µm) had greater RNFL thickness reduction than the non-DON group (-3.9 ± 5.4 µm) (P = 0.002). Bone removal decompression was associated with decreased RNFL in the non-DON (P = 0.025; ß = -2.49) and DON (P = 0.042; ß = -9.43) groups. Three cases who were hard to operate due to extensive fibrosis experienced severe vision loss postoperatively due to anterior ischemic optic neuropathy, posterior ischemic optic neuropathy, and posterior ciliary artery occlusion, respectively. Conclusions: TED patients experienced subclinical optic nerve injury and significant RNFL loss after the orbital decompression surgery. Aggressive manipulation during decompression surgery may lead to dreadful vision loss. Tailored surgical plans and delicate manipulation are warranted.

Correlations between visual acuity and macular microvasculature quantified with optical coherence tomography angiography in diabetic macular oedema.

PURPOSE: To explore the impact of macular ischaemia on vision in diabetic macular oedema (DMO) by analysing the correlations between visual acuity and macular microvascular parameters using optical coherence tomography angiography (OCTA). METHODS: OCTA was performed in 81 eyes of 48 patients with DMO, and 3 × 3-mm2 en face OCTA images of the superficial capillary plexus and deep capillary plexus in the central macula were retrospectively collected. Microvascular parameters including the number of microaneurysms, area of foveal avascular zone (FAZ), acircularity index of FAZ, vessel density, skeleton density, vessel density index and fractal dimension were measured. Central retinal thickness (CRT) and the presence of ellipsoid zone disruption at the fovea were also recorded. Linear mixed models were used to evaluate the correlations between best-corrected visual acuity (BCVA) and the microvascular parameters. RESULTS: After adjustment for CRT and ellipsoid zone disruption at the fovea, lower skeleton density and lower fractal dimension in the deep capillary plexus were correlated with poorer BCVA (P = 0.030 and 0.024, respectively). None of the microvascular parameters of the superficial capillary plexus were correlated with BCVA after adjustment for CRT and ellipsoid zone disruption (all, P > 0.05). CONCLUSIONS: For eyes with DMO, low skeleton density and low branching complexity in the deep capillary plexus of central macula were correlated with poor vision. OCTA could offer quantified parameters of macular microvasculature to measure the impact of macular ischaemia on visual acuity in DMO.

OCT Angiography Biomarkers for Predicting Visual Outcomes after Ranibizumab Treatment for Diabetic Macular Edema.

PURPOSE: To correlate quantitative OCT angiography (OCTA) biomarkers with clinical features and to predict the extent of visual improvement after ranibizumab treatment for diabetic macular edema (DME) with OCTA biomarkers. DESIGN: Retrospective, longitudinal study in Taiwan. PARTICIPANTS: Fifty eyes of 50 patients with DME and 22 eyes of 22 healthy persons, with the exception of cataract and refractive error, from 1 hospital. METHODS: Each eye underwent OCT angiography (RTVue XR Avanti System with AngioVue software version 2017.1; Optovue, Fremont, CA), and 3×3-mm2 en face OCTA images of the superficial layer and the deep layer were obtained at baseline and after 3 monthly injections of ranibizumab in the study group. OCT angiography images also were acquired from the control group. MAIN OUTCOME MEASURES: Five OCTA biomarkers, including foveal avascular zone (FAZ) area (FAZ-A), FAZ contour irregularity (FAZ-CI), average vessel caliber (AVC), vessel tortuosity (VT), and vessel density (VD), were analyzed comprehensively. Best-corrected visual acuity (BCVA) and central retinal thickness (CRT) also were obtained. Student t tests were used to compare the OCTA biomarkers between the study group and the control group. Linear regression models were used to evaluate the correlations between the baseline OCTA biomarkers and the changes of BCVA and CRT after treatment. RESULTS: Eyes with DME had larger AVC, VT, FAZ-A, and FAZ-CI and lower VD than those in the control group (P < 0.001 for all). After the loading ranibizumab treatment, these OCTA biomarkers improved but did not return to normal levels. Among all biomarkers, higher inner parafoveal VD in the superficial layer at baseline correlated most significantly with visual gain after treatment in the multiple regression model with adjustment for CRT and ellipsoid zone disruption (P < 0.001). To predict visual improvement, outer parafoveal VD in the superficial layer at the baseline showed the largest area under the receiver operating characteristic curve (0.787; P = 0.004). No baseline OCTA biomarkers showed any significant correlation specifically with anatomic improvement. CONCLUSIONS: For eyes with DME, parafoveal VD in the superficial layer at baseline was an independent predictor for visual improvement after the loading ranibizumab treatment.

Combination of phototherapeutic keratectomy and wavefront-guided photorefractive keratectomy for the treatment of Thiel-Behnke corneal dystrophy.

Phototherapeutic keratectomy (PTK) has been used to treat anterior corneal dystrophy but may cause hyperopic shift or corneal high-order aberration. We describe the successful treatment of a case of a 43-year-old female with Thiel-Behnke corneal dystrophy, using PTK followed by wavefront-guided photorefractive keratectomy (PRK). The patient had high corneal aberration and hyperopic shift after PTK in both eyes. The corneal surface regularity index and surface asymmetric index increased after PTK and decreased after wavefront-guided PRK. Vision improved from preoperative 20/400 and 20/60 to postoperative 20/20 and 20/25 in the right eye and the left eye, respectively. Additional wavefront-guided PRK may enhance the effects of PTK by reducing irregular corneal surfaces and by correcting PTK-induced hyperopic shift.

High-resolution melting and real-time PCR for quantification and detection of drug-resistant HBV mutants in a single amplicon.

BACKGROUND: Antiviral therapy by nucleoside/nucleotide analogues (NAs) effectively reduces HBV replication in chronic hepatitis B (CHB) patients. Because long-term NA treatments will eventually select for drug-resistant mutants, early detection of mutants and frequent monitoring of viral loads is crucial for successful NA therapy. Because no efficient test for one-tube quantification and qualification of various HBV-resistant mutants exists, we propose to use high-resolution melting (HRM) analysis in combination with real-time PCR to achieve this unmet need. METHODS: We developed a single amplicon for detecting HBV mutants resistant to lamivudine (LMV), adefovir (ADV) and entecavir (ETV), which are commonly used for CHB treatment. Our design consists of two steps: real-time PCR for viral quantification, and hybridization probe HRM analysis for detection of specific drug-resistant mutants. RESULTS: Assay quantification was accurate (R=0.98) for viral loads from 10(3) to 10(9) copies/ml. HRM analysis produced distinct melting temperatures that clearly distinguished the mutants, rtM204V/I (LMV), rtA181V and rtN236T (ADV), and rtT184G and rtM250V (ETV), from their respective wild types. The assay detected mutants at only 10-25% of the HBV population. The clinical applicability of this assay was tested in a pilot study with serial samples from patients receiving LMV treatment. CONCLUSIONS: Flexibility, speed and cost-efficiency are additional benefits unique to our assay. The clinical sample results further support the feasibility of applying our design to frequent and long-term monitoring of CHB patients receiving NA treatments in the clinical setting.