Novel Application of Conjunctival Anterior Segment Optical Coherence Tomography Angiography to Assess Ocular Redness.

PURPOSE: The aim of this study was to determine anterior segment optical coherence tomography angiography (AS-OCTA) parameters to assess ocular redness severity. METHODS: AS-OCTA analyses of 60 eyes of 40 patients were grouped according to ocular redness stages using the 5-category validated bulbar redness scale in a cross-sectional retrospective study (groups 1-5). A subset of patients with slit-lamp photographs, total 35 eyes of 23 patients, were assessed with 10-category validated bulbar redness scale for comparison. AS-OCTA images of nasal and temporal bulbar conjunctiva were analyzed. Vessel density (VD) represented the blood flow pixels by the total pixels of image (%); vessel diameter index represented the VD by the skeletonized density; fractal dimension, measured with the box-count method, represented the vessel branching complexity. Averaged nasal and temporal parameters for each eye were correlated to validated bulbar redness scales. RESULTS: There was no statistical difference between groups for age ( P = 0.118), sex ( P = 0.501), eye laterality (OD/OS; P = 0.111), or location (nasal/temporal; P = 0.932). In the 5-category scale, VD significantly increased from group 1 to 2 (31.5 ± 1.9% and 33.4 ± 2.2%, P = 0.023), 2 to 3 (36.0 ± 3.5%, P < 0.001), and 4 to 5 (40.2 ± 2.9 and 46.5 ± 2.8, P < 0.001). The correlations were 0.805 ( P < 0.001) and 0.893 ( P < 0.001) for the 5-category and 10-category scales, respectively. Vessel diameter index showed a significant increase from 1 to 2 (2.90 ± 0.17 and 3.00 ± 0.15; P = 0.004) and 4 to 5 (2.92 ± 0.31 and 3.33 ± 0.08; P = 0.001). The correlations were 0.550 ( P < 0.001) and 0.625 ( P < 0.001) for the respective scales. The fractal dimension showed no significant differences between subsequent groups. The correlations were 0.445 ( P < 0.001) and 0.583 ( P < 0.001), respectively. CONCLUSIONS: Conjunctival AS-OCTA VD was the most reliable parameter to assess ocular redness.

Anterior segment optical coherence tomography angiography in the assessment of ocular surface lesions.

PURPOSE: Describe the utility of anterior segment optical coherence tomography angiography (AS-OCTA) to assess ocular surface lesions. METHODS: Retrospective, case-control study of 10 eyes of 9 patients with malignant lesions and 23 eyes of 22 patients with benign lesions. Lesions included 13 epithelial, 10 pigmented and 10 lymphoid lesions. Graders performed an average of 3 depth and diameter measurements of peri-lesional vessels entering each lesion on AS-OCTA. Statistical models to assess differences between groups accounted for bilateral eye inclusion and lesion thickness (on AS-OCT). Receiver operating characteristic (ROC) curve and area under the curve (AUC) were performed for each parameter. RESULTS: In the benign and malignant groups, age was 49.5 ± 22.4 and 64.3 ± 10.6 years (p = 0.145) with 45% males and 55% males (p = 0.458), in their respective groups. AS-OCTA showed greater peri-lesional vessel depth and diameter in malignant lesions (315.2 ± 73.0 µm, p < 0.001 and 76.4 ± 18.2 µm, p < 0.001; respectively) compared to benign lesions (199.4 ± 34.1 µm and 44.0 ± 9.4 µm, respectively). Malignant lesions showed deep and dilated peri-lesional vessels, which may represent feeder vessels. Vessel depth showed AUC = 0.980, 90.9% sensitivity and 100.0% specificity with a 236.5 µm cutoff. Vessel diameter showed AUC = 0.960, 100.0% sensitivity and 88.9% specificity with a 53.9 µm cutoff. CONCLUSION: AS-OCTA shows greater peri-lesional vessel depth and diameter of malignant lesions compared to benign lesions. This imaging modality provides novel and non-invasive functional vascular parameters that can potentially aid the assessment of ocular surface lesions.

The utility of anterior segment optical coherence tomography angiography for the assessment of limbal stem cell deficiency.

PURPOSE: To determine the utility of anterior segment optical coherence tomography angiography (AS-OCTA) in assessing limbal stem cell deficiency (LSCD). METHODS: Twenty-six eyes of 24 LSCD patients, classified clinically into stage I, II and III, and 12 eyes of 12 healthy subjects were included. AS-OCTA images were analyzed by two masked observers, measuring the maximum corneal vascular extension (CoVE) from the limbus to the furthest vessel over the cornea, and corneal vascular thickness (CoVT) from the most superficial to the deepest corneal vessel. RESULTS: CoVE was 0.27 ± 0.10, 0.79 ± 0.21, 1.68 ± 0.89 and 2.53 ± 0.82 mm in controls, stage I, II and III LSCD, respectively (p < 0.001). The CoVT was 51.0 ± 19.4, 113.7 ± 36.6, 129.7 ± 39.3 and 336.0 ± 85.0 µm, respectively (p < 0.001). There was a significant difference in CoVE and CoVT between all stages compared to controls, and between stage I and III LSCD (p < 0.001). Further, CoVE showed a significant difference between stage I and II, whereas CoVT showed a significant difference between stage II and III LSCD (p < 0.001). BCVA showed strong correlation with CoVT (r = 0.765, p < 0.001) and moderate correlation with CoVE (r = 0.547, p = 0.001). AS-OCTA parameters showed excellent intra- and inter-class correlation coefficients (>0.900). CONCLUSION: LSCD demonstrates significant changes in CoVE and CoVT as early as stage I LSCD in comparison to controls. CoVE and CoVT strongly correlate to both disease severity and BCVA. AS-OCTA may provide novel quantitative and non-invasive parameters to assess LSCD.

Novel Parameters to Assess the Severity of Corneal Neovascularization Using Anterior Segment Optical Coherence Tomography Angiography.

PURPOSE: Assessment of anterior segment-optical coherence tomography angiography (AS-OCTA) to determine severity of corneal neovascularization (CoNV). DESIGN: Retrospective, cross-sectional, single-center study. METHODS: Patients of various CoNV etiologies were selected and classified into mild, moderate, and severe. Their AS-OCTA images were measured for CoNV anterior limit, CoNV posterior limit, CoNV thickness, CoNV depth%, CoNV vessel density, CoNV area, and CoNV volume. Further, AS-OCTA parameters were correlated to clinical parameters, such as classification, a numerical severity scale, vascular clock hours, and best-corrected visual acuity (BCVA). RESULTS: A total of 19 mild, 10 moderate, and 6 severe CoNV eyes were included with no significant age-gender differences. CoNV depth% and volume increased from mild to moderate (9.3 ± 1.1% to 17.7 ± 3.3%, P = .030, and 0.2 ± 0.1 mm3 to 1.0 ± 0.3 mm3, P = .025, respectively) and from moderate to severe CoNV (44.6 ± 5.3%, P < .001, and 2.0 ± 0.3 mm3, P = .014, respectively). CoNV area and posterior limit increased from mild to moderate (1.7 ± 0.3 mm2 to 4.6 ± 0.7 mm2, P = .001, and 217.7 ± 16.8 µm to 349.1 ± 54.9 µm, P = .048, respectively), not from moderate to severe (P = .999 and P = .403, respectively). CoNV thickness increased from moderate to severe (218.2 ± 46.6 µm to 340.2 ± 8.7 µm, P = .020), but not from mild to moderate. CoNV area and volume showed good correlations to CoNV staging (r = 0.703 and r = 0.771, respectively; P < .001) and severity scale (r = 0.794 and r = 0.712, respectively; P < .001). CoNV area showed good correlation to clock hours (r = 0.749, P < .001). CoNV depth and volume showed good correlation to BCVA (r = 0.744 and r = 0.722, respectively; P < .001). CoNV anterior limit and vessel density showed no significant correlations (P ≥ .05). CONCLUSIONS: Severe CoNV shows greater CoNV posterior limit, thickness, depth%, area, and volume on AS-OCTA compared to mild. CoNV volume and depth strongly correlate to BCVA. AS-OCTA provides novel, quantitative, and noninvasive parameters for assessing CoNV severity.

Phacoemulsification with intraocular lens implantation after previous descemetorhexis without endothelial keratoplasty.

A 58-year-old woman with bilateral Fuchs endothelial corneal dystrophy presented with predominantly central guttata in the left eye causing visually significant stromal edema. A 4.0 mm descemetorhexis without endothelial keratoplasty was performed. At the 6-week follow-up, the central cornea had cleared completely and the central endothelial cell density (ECD) was 541 cells/mm2. The central corneal clearing remained stable for 2 years after the procedure; however, vision declined because of a visually significant cataract in the left eye. Uneventful phacoemulsification with intraocular lens implantation was performed with a target refraction of -0.50 diopters. At 1.5 months postoperatively, the uncorrected distance visual acuity was 20/20 with a manifest refraction of -0.25 -0.25 × 60 and the central ECD was 2373 cells/mm2 (increased from 1471 cells/mm2 prior to phacoemulsification). Cataract surgery by phacoemulsification years after descemetorhexis without endothelial keratoplasty appears to be well-tolerated, with good clinical and predictive refractive outcomes.

Optical coherence tomography analysis of hydrofluoric acid decontamination of human cornea by mannitol solution.

PURPOSE: To evaluate the efficacy of mannitol solution as a decontamination agent on the chemical burn of the human corneas. METHODS: Eight donor corneas from an eye bank were exposed to 25µl of 2.5% hydrofluoric acid (HF) solution on a filter paper for 20s. Three eyes were rinsed with 1000ml of mannitol 20% for 15min immediately after removal of the filter paper, 3 other were rinsed with sodium chloride (NaCl) 0.9% (1000ml for 15min) and two eyes were not rinsed. Microstructural changes were monitored in the time domain by optical coherence tomography (OCT) imaging for 75min. RESULTS: NaCl reduced the penetration depth to approximately half the thickness of the cornea at 15min; scattering within the anterior cornea was higher than that for the unrinsed eye. With mannitol, no increased scattering was observed in the posterior part of the corneal stroma within a time period of 1h after rinsing. OCT images revealed low-scattering intensity within the anterior stroma at the end of the rinsing period. CONCLUSION: In eye bank human corneas, mannitol proved to be an efficient agent to decontaminate HF burn.

Descemet Membrane Detachment in Femtosecond Laser-Assisted Cataract Surgery.

PURPOSE: To report a case series of 4 patients with Descemet membrane detachment (DMD) after undergoing femtosecond laser-assisted cataract surgery incisions. METHODS: Case report. RESULTS: DMD was noted at the secondary incision (n = 2) or at the main incision (n = 2). All the secondary incision and 1 main incision DMD were resolved with intraoperative maneuvers. Delay in recognizing DMD intraoperatively at the principal incision in 1 case led to inadvertent aspiration of a part of it and persistent postoperative corneal edema. This complication was handled with Descemet membrane endothelial keratoplasty 1 month after initial surgery. CONCLUSIONS: DMD can occur after femtosecond laser-assisted cataract surgery, although it is a rare complication as it is in traditional phacoemulsification. The surgeon must be prepared to recognize it, manage it intraoperatively, and treat it postoperatively to reduce the risk of permanent damage to the eye.

Toric intraocular lens misalignment inducing astigmatism after refractive surgery.

PURPOSE: To report the unexpected induction of astigmatism after phacoemulsification and toric intraocular lens (IOL) implantation in an eye with previous corneal refractive surgery. METHODS: Case report of a 46-year-old man with bilateral nuclear cataract and previous photorefractive keratectomy. Because corneal topography identified regular corneal astigmatism at the central optical zone, phacoemulsification and implantation of a one-piece hydrophobic acrylic toric IOL were performed. RESULTS: Unexpected induction of astigmatism occurred in the first operated eye despite proper alignment of the IOL according to the preoperative calculations using simulated K values to determine toric IOL power and alignment. A retrospective qualitative analysis of corneal topography showed mismatching of the steepest meridian, leading to an off-axis IOL. Secondary IOL rotation improved both uncorrected and corrected distance visual acuity. CONCLUSIONS: Qualitative analysis of the corneal topography is mandatory during the assessment of toric IOL alignment in eyes with previous corneal refractive surgery to identify the actual location of the steepest meridian.