Faculty Bibliography

BACKGROUND AND OBJECTIVE/OBJECTIVE:To quantify fractal dimension (FD) by mass-radius method in optical coherence tomography angiography (OCTA) images and characterize microvascular differences in eyes with and without diabetic retinopathy (DR). PATIENTS AND METHODS/METHODS:A retrospective study was conducted using OCTA images of 3 mm × 3 mm and 6 mm × 6 mm scans for superficial and deep capillary plexuses from 49 control eyes and 58 eyes with DR. RESULTS:< .05). In the 3 mm × 3 mm superficial plexus, the FD of severe nonproliferative DR (NPDR) and proliferative DR (PDR) were significantly lower compared to control. The scans of the deep plexus showed only severe NPDR was significantly reduced in the 6 mm × 6 mm scan, whereas moderate NPDR, severe NPDR, and PDR were significantly lower in the 3 mm × 3 mm scan. CONCLUSION/CONCLUSIONS:.

PURPOSE/OBJECTIVE:To report a case of bilateral toxic corneal and conjunctival epitheliopathy secondary to administration of filter paper impregnated with lysergic acid diethylamide (LSD) in the inferior conjunctival fornices. METHODS:This is a single case report of an 18-year-old man who presented to the emergency department with acute, bilateral eye pain and redness of 24 hours. The patient admitted to placing folded strips of blotting paper impregnated with LSD into the inferior fornices of his eyes the previous night. RESULTS:The patient was found to have localized bilateral corneal and conjunctival abrasions with underlying subconjunctival hemorrhage. Conjunctival abrasion was "kissing," involving the bulbar and palpebral conjunctiva, corresponding to the presumed location of the filter paper. There was no corneal stromal opacification. He was lost to follow up within 1 week of initial presentation but stated that his symptoms improved. CONCLUSIONS:To the best of our knowledge, this is the first reported case of bilateral hemorrhagic conjunctival abrasion and corneal abrasion secondary to LSD. "Kissing" conjunctival lesions, which have been previously reported with heroin use, should raise suspicion for drug abuse.

PURPOSE: To use fractal dimensional analysis to investigate retinal vascular disease patterns in patients with diabetic retinopathy using spectral domain optical coherence tomography angiography. METHODS: A retrospective study was conducted which included 49 eyes from 26 control subjects and 58 eyes from 35 patients known to have diabetic retinopathy. Of the 58 eyes with known retinopathy, 31 were categorized as nonproliferative diabetic retinopathy (13 mild, 9 moderate, and 9 severe) and 27 were categorized as proliferative diabetic retinopathy. Optical coherence tomography angiography images were acquired using the RTVue XR Avanti (Optovue, Inc). Automated segmentation was obtained through both the superficial and deep capillary plexuses for each eye. Grayscale optical coherence tomography angiography images were standardized and binarized using ImageJ (National Institutes of Health). Fractal box-counting analyses were conducted using Fractalyse (TheMA). Fractal dimensions (FDs) and correlation coefficient of the superficial and deep capillary plexuses were compared between control eyes and those in various stages of diabetic retinopathy. RESULTS: The superficial and deep capillary plexuses from diabetic and control eyes were analyzed. The average FD for diabetic eyes was significantly lower than in control eyes in the superficial plexus (P = 2.4 x 10) and in the deep capillary plexus (P = 1.87 x 10 ) with a more statistically significant difference noted in the deep capillary plexus. When analyzing diabetic patients without edema noted on optical coherence tomography, the FD was significantly reduced in the superficial (P = 0.001) and deep (P = 1.49 x 10) plexuses. When analyzing diabetic patients with edema noted on optical coherence tomography, the FD was significantly reduced in the superficial (P = 2.0 x 10) and deep (P = 1.85 x 10) plexuses. CONCLUSION: The optical coherence tomography angiography FD is significantly lower in both superficial and deep capillary plexuses in eyes with all stages studied of diabetic retinopathy. The results were more often significant for the deep capillary plexus. The use of fractal analysis provides an objective criterion to assess microvascular disease burden in diabetic retinopathy.

Purpose/UNASSIGNED:To investigate whether preoperative corneal topographic and biomechanical parameters (CTBPs) predict postoperative residual refractive error (RRE). Methods/UNASSIGNED:We retrospectively included 151 eyes from 151 patients of small-incision lenticule extraction (SMILE) with target RRE of plano and 3-month measurements of refractive error from Tianjin Eye Hospital. Multivariate linear/logistic regressions were performed to associate age, gender, preoperative refractive error, lenticule thickness, and CTBPs with postoperative RRE/the occurrence of myopic RRE ≤ -0.25 diopter (D). Stepwise regression was used for feature selection. Leave-one-cross-validation was used for model evaluation by the area under the receiver operating characteristic curve (AUC). Results/UNASSIGNED:< 0.001) improved the AUC performance to 0.771 from 0.615. Conclusions/UNASSIGNED:Postoperative outcomes of SMILE can be predicted by individual CTBPs. Translational Relevance/UNASSIGNED:Our findings could be used to customize a refractive nomogram based on individual corneal properties improving outcomes and patient satisfaction.

Purpose: To assess whether microvascular dropout as measured by fractal self-similarity breakdown of optical coherence tomography angiography (OCTA) occurs in a sectoral fashion in eyes with primary open angle glaucoma (POAG) compared to control patients.
Method(s): A retrospective study using OCTA images obtained on 40 eyes with POAG, and 14 control eyes. OCTA images with peripapillary scans of 4.5mm x 4.5mm diameters were obtained using RTVue XR Avanti (Optovue Inc., Fremont, CA, USA), and standardized and binarized using ImageJ (National Institutes of Health, Bethesda, Maryland, USA). Fractal dimension by means of box-counting algorithm using box sizes with increasing exponential factor of two with grid algorithm on Fractalyse (TheMA, Besancon Cedex, France) was plotted against linear box dimension and first local peak (FLP) representing smallest box size resolution before breakdown of self-similarity was recorded. The ratio of superior to inferior (SI Ratio) of FLP was the main outcome measure.
Result(s): There is significant difference between control and POAG eyes (p = 0.01), with POAG having larger superior to inferior (SI Ratio) of FLP (1.40 +/-0.93) compared to control (1.00 +/-0.0). The increased SI FLP ratio of the POAG eyes reflects a preferential loss of self-similarity in the superior quadrant (i.e. higher FLP values) rather than increased self-similarity in the inferior quadrant (FLP inferior = 8.0 +/-0 and FLP superior = 11.2 +/-7.4 in POAG, FLP inferior = 8.0 +/-0 and FLP superior = 8.0 +/-0 in controls).
Conclusion(s): The measurement of box size of the first local maximum of fractal dimension as a function of increasing box size represents the smallest box size resolution prior to loss of uniformity of the vascular pattern's fractal dimension. While this loss of uniformity may be related to resolution in normal eyes, the preferential loss of microvascular complexity inferior to the optic disc in POAG eyes suggests asymmetric small vessel dropout in the POAG. This accords well with the asymmetric loss demonstrated in a prior OCTA study. Our study was not designed to determine whether microvascular loss occurred as a consequence or as a cause of axonal loss. We propose FLP SI Ratio as a useful measure of POAG-associated microvascular dropout

Purpose: To study fractal dimensional of retinal vascular disease in patients with diabetic retinopathy(DR) with and without macular edema using spectral-domain optical coherence tomography angiography(OCTA) Methods: A retrospective study of 49 control eyes from and 58 diabetic eyes. Of the 58 diabetic eyes, 23 had macular edema and 35 did not. OCTA images were acquired using the RTVue XR Avanti(Optovue,Inc.Fremont, CA).Automated segmentation through the superficial and deep capillary plexuses was obtained. Grayscale OCTA images were standardized and binarized using ImageJ(NIH, Bethesda, Maryland, USA). Fractal boxcounting analyses were performed with Fractalyse(TheMA, Besancon Cedex, France). Fractal dimensions(FD) were compared using two-tailed t-tests Results: The mean foveal and parafoveal thickness of all eyes studied was recorded as per OCTA imaging reports (Table 1). The mean FD for the superficial and deep plexuses of control eyes was 1.651(SD=0.05391) and 1.677(SD=0.05325), respectively. The mean FD for diabetic eyes without edema was 1.6(SD=0.07) for the superficial plexus and 1.59(SD=0.07) for the deep plexus. There was significant reduction in nonedematous eyes in the superficial plexus (p=0.001) and deep plexus (p=1.49x10 ). The mean FD for diabetic eyes with edema was 1.57(SD=0.066) for the superficial plexus and 1.53(SD=0.075) for the deep plexus. There was significant reduction in edematous eyes in the superficial plexus (p=2.08x10 ) and deep plexus (p=1.85x10 ) Conclusions: The OCTA FD is significantly lower in the superficial and deep capillary plexuses in eyes with DR whether macular edema is present or not. Utilization of FD gives an objective criterion to assess microvascular disease burden in DR with and without macular edema

Purpose: Optical coherence tomography angiography (OCTA) permits non-invasive evaluation of the retinal vasculature. We aim to quantify the fractal dimension (FD) of eyes with birdshot chorioretinopathy compared with control eyes using OCTA. Methods: A retrospective study was performed on 49 eyes from 26 control patients and 12 eyes from 6 patients with birdshot chorioretinopathy from a previously established database. OCTA images were obtained using the RTVue XR Avanti (Optovue Inc., Fremont, CA, USA). Automated 3mm x 3mm macular scans were obtained through both the superficial and deep capillary plexuses for each eye. Grayscale OCTA images were standardized and binarized using ImageJ (National Institutes of Health, Bethesda, Maryland, USA). Fractal box-counting analyses were performed using Fractalyse (TheMA, Besancon Cedex, France). The FD of the deep and superficial plexuses of eyes with birdshot chorioretinopathy was compared with control eyes. Statistical analysis was performed using two-tailed t-tests and one-way analysis of variance with post-hoc Tukey's multiple comparisons test with statistical significance at P<0.05. Results: The mean FD in the superficial capillary plexus of eyes with birdshot chorioretinopathy (1.481, SD=0.082) was significantly lower (P<0.0001) than control eyes (1.651, SD=0.0539). The mean FD in the deep capillary plexus of eyes with birdshot chorioretinopathy (1.512, SD=0.0904) was significantly lower (P<0.0001) than control eyes (1.677, SD=0.0533). There was no difference between the superficial and deep capillary plexuses of eyes with birdshot chorioretinopathy. Conclusions: The fractal dimension in OCTA of birdshot chorioretinopathy is significantly lower compared to control eyes. Since fractal geometry models the branching in the parafoveal microvasculature, this may correlate with a lower density of capillaries with above-threshold flow and provide further insight into pathogenesis of birdshot chorioretinopathy. Utilizing fractal analysis in OCTA imaging has the potential to establish quantitative parameters for parafoveal microvascular pathology in birdshot chorioretinopathy