Short-term postoperative changes in the choroidal vascularity index in patients with a unilateral epiretinal membrane.

BACKGROUND: To investigate short-term choroidal structural and vascular changes after epiretinal membrane (ERM) surgery. METHODS: In this retrospective study, 65 patients with unilateral ERM underwent pars plana vitrectomy combined with cataract surgery and were examined one day before surgery and one week, one month, and three months after surgery. Choroidal thickness (CT) and choroidal vascular index (CVI) were evaluated using horizontal enhanced depth imaging optical coherence tomography (EDI-OCT) scans and were further calculated using semi-automatic algorithms using MATLAB R2017a. RESULTS: Preoperatively, CVI was higher in eyes with ERM (61.70 ± 5.17%) than in fellow eyes (59.99 ± 5.26%). CVI increased significantly at one week after surgery (62.14 ± 5.02%) and decreased at 1 and 3 months after surgery (60.76 ± 4.97% and 60.4 ± 4.83%, respectively). The change was pronounced in the nasal region (p < 0.001) and central region (p < 0.05). CT in the temporal macula increased at 1 week (239.65 ± 72.98 µm) after surgery and decreased at 1 and 3 months after surgery (222.15 ± 71.91 µm and 222.33 ± 65.72 µm, respectively; p < 0.01). CONCLUSIONS: Short-term postoperative variations in the choroid have been demonstrated in eyes with ERM. This may be related to the release of macular traction. CVI assessment using EDI-OCT may be a useful tool for investigating choroidal structural changes accompanying ERM and postoperative period.

IMPACT OF PENETRATION AND IMAGE ANALYSIS IN OPTICAL COHERENCE TOMOGRAPHY ON THE MEASUREMENT OF CHOROIDAL VASCULARITY PARAMETERS.

PURPOSE: To investigate the impact of penetration and image analysis in different optical coherence tomography (OCT) instruments on the measurement of choroidal vascularity parameters. METHODS: Twenty-three healthy volunteers were imaged using two swept-source OCTs and one spectral-domain OCT. A fully automatic segmentation method based on ResNet-UNet and Niblack local threshold binarization was performed to quantify the relevant choroidal vascular parameters, including choroidal vascularity index, total choroidal volume, and luminal volume. The intraclass correlation coefficient (ICC) and coefficient of repeatability (COR) were used to analyze the repeatability and consistency of automatic and manual segmentation, respectively. RESULTS: Both swept-source OCT devices showed good consistency of luminal volume and total choroidal volume measurements (all ICC value >0.98 with COR% < 8.53%) based on manual segmentation, whereas the consistency of the spectral-domain OCT was lower (ICC value <0.60 with COR% > 40%), which was greatly improved after using the automatic algorithm (ICC value >0.99 with COR% < 4%). The repeatability of choroidal vascularity index obtained from different OCT images using manual or automatic segmentation showed good agreement (all ICC values >0.85), whereas the choroidal vascularity index measurement from the spectral-domain OCT was larger than the other two swept-source OCT devices (ICC value <0.65). CONCLUSION: For healthy youngsters, the penetration of OCT plays a role in the measurement precision for choroidal vascularity parameters, and automatic segmentation can improve the ability of choroidal boundary identification with deficient penetration, suggesting these factors need to be considered in clinical work.

Differentiate Thyroid Follicular Adenoma from Carcinoma with Combined Ultrasound Radiomics Features and Clinical Ultrasound Features.

Noninvasive differentiating thyroid follicular adenoma from carcinoma preoperatively is of great clinical value to decrease the risks resulted from excessive surgery for patients with follicular neoplasm. The purpose of this study is to investigate the accuracy of ultrasound radiomics features integrating with ultrasound features in the differentiation between thyroid follicular carcinoma and adenoma. A total of 129 patients diagnosed as thyroid follicular neoplasm with pathologically confirmed follicular adenoma and carcinoma were enrolled and analyzed retrospectively. Radiomics features were extracted from preoperative ultrasound images with manually contoured targets. Ultrasound features and clinical parameters were also obtained from electronic medical records. Radiomics signature, combined model integrating radiomics features, ultrasound features, and clinical parameters were constructed and validated to differentiate the follicular carcinoma from adenoma. A total of 23 optimal features were selected from 449 extracted radiomics features. Clinical and ultrasound parameters of sex (p = 0.003), interior structure (p = 0.035), edge (p = 0.02), platelets (p = 0.007), and creatinine (p = 0.001) were associated with the differentiation between benign and malignant follicular neoplasm. The values of area under curves (AUCs) of the radiomics signature, clinical model, and combined model were 0.772 (95% CI: 0.707-0.838), 0.792 (95% CI: 0.715-0.869), and 0.861 (95% CI: 0.775-0.909), respectively. A final corrected AUC of 0.844 was achieved for the combined model after internal validation. Radiomics features from ultrasound images combined with ultrasound features and clinical factors are feasible to differentiate thyroid follicular carcinoma from adenoma noninvasive before operation to decrease the unnecessary of diagnostic thyroidectomy for patients with benign follicular adenoma.

Identification of peripheral anterior synechia with anterior segment optical coherence tomography.

PURPOSE: To generate a model that evaluates the presence and extent of peripheral anterior synechia (PAS) based on anterior segment optical coherence tomography (AS-OCT). METHODS: The extent of PAS involvement in the eyes of patients with angle closure was assessed by indentation gonioscopy, and the part of non-PAS and PAS were assigned into two groups (NPAS and PAS). Anterior chamber angles were then imaged by AS-OCT with light-emitting diode (LED) irradiation directly into the pupils, leading to pupillary constriction and increasing anterior chamber angle width. Parameters including the angle opening distance at 750 µm anterior to the scleral spur (AOD750) and trabecular-iris space area at 750 µm anterior to the scleral spur (TISA750) were then obtained. The differences before and after LED irradiation of AOD750 and TISA750 were calculated and used to generate a PAS model based on binary logistic regression. Validation data were then tested. RESULTS: A total of 258 AS-OCT images in 14 eyes were assigned to the modeling data, and 120 were assigned to the validation data. There were no differences in AOD750 and TISA750 in the dark between NPAS and PAS (PAOD750 = 0.258, PTISA750 = 0.486), whereas after LED light exposure, TISA750light was larger in NPAS than in PAS (P = 0.047). The light-dark differences of both parameters showed significant differences between the two groups (PAOD750dif = 0.019, PTISA750dif < 0.001). The area under the curve of the model performance was 0.841, and the overall correct rate was 80.8% based on the validation data. CONCLUSIONS: The present study demonstrates that the AS-OCT-based PAS model could be useful in the identifying of the presence of synechial angle closure and evaluating the extent of PAS in a single eye.

Automated delineation of corneal layers on OCT images using a boundary-guided CNN.

Accurate segmentation of corneal layers depicted on optical coherence tomography (OCT) images is very helpful for quantitatively assessing and diagnosing corneal diseases (e.g., keratoconus and dry eye). In this study, we presented a novel boundary-guided convolutional neural network (CNN) architecture (BG-CNN) to simultaneously extract different corneal layers and delineate their boundaries. The developed BG-CNN architecture used three convolutional blocks to construct two network modules on the basis of the classical U-Net network. We trained and validated the network on a dataset consisting of 1,712 OCT images acquired on 121 subjects using a 10-fold cross-validation method. Our experiments showed an average dice similarity coefficient (DSC) of 0.9691, an intersection over union (IOU) of 0.9411, and a Hausdorff distance (HD) of 7.4423 pixels. Compared with several other classical networks, namely U-Net, Attention U-Net, Asymmetric U-Net, BiO-Net, CE-Net, CPFnte, M-Net, and Deeplabv3, on the same dataset, the developed network demonstrated a promising performance, suggesting its unique strength in segmenting corneal layers depicted on OCT images.

Unique changes in the retinal microvasculature reveal subclinical retinal impairment in patients with systemic lupus erythematosus.

PURPOSE: To determine the changes of the microvasculature and microstructure in the inner intra-retinal layers in systemic lupus erythematosus (SLE) patients without lupus retinopathy (LR). METHODS: Thirty-two SLE patients (58 eyes) without LR (NLR), 14 patients (22 eyes) with LR and 50 healthy subjects (50 eyes) were enrolled. Spectral domain optical coherence tomography equipped with Angiovue was used to obtain three-dimensional retinal thickness maps and microvascular images of the superficial and deep retinal capillary plexuses (SRCP/DRCP) around the macula. Quantitative analyses were performed using a custom automated algorithm. Disease activity of patients was assessed using the SLE disease activity index (SLEDAI). RESULTS: Retinal capillary skeleton density of the SRCP in SLE patients without LR was significantly lower than the controls in almost all regions, which further decreased in the LR group (P < .05). No significant changes were evident in DRCP of the NLR group (P > .05). The inner retina in the LR group was significantly thinner than the controls in most regions, though there were only a few regions that were different between the NLR and the control groups (P < .05). There were significant differences of the SLEDAI scores between the two SLE groups. CONCLUSION: Significantly lower density in SRCP and regional thinning in inner retina were observed in the SLE patients without clinical fundus changes. OCT equipped with Angiovue might be useful in evaluating the microvascular and microstructural disorders of the inner retinal layers in SLE patients, which may contribute a quantitative approach to the early diagnosis and progression of LR.

CHARACTERIZATION BY FRACTAL DIMENSION ANALYSIS OF THE RETINAL CAPILLARY NETWORK IN PARKINSON DISEASE.

PURPOSE: To characterize retinal capillary complexity by optical coherence tomography angiography in Parkinson disease. METHOD: Twenty-five Parkinson disease patients and 25 age- and gender-matched healthy controls were recruited. Optical coherence tomography angiography and optical coherence tomography imaged the superficial and deep retinal capillary plexuses and retinal structure. Retinal capillary skeleton density, retinal capillary perfusion density, and fractal dimension analysis of retinal capillary complexity were performed in the total annular zone and quadrant sectors. The thickness of retinal nerve fiber layer, ganglion cell layer and inner plexiform layer, and total retinal thickness were extracted from retinal structural images. Relationships among the retinal capillaries, retinal structure, and clinical parameters were analyzed. RESULTS: The superficial retinal capillary plexus in Parkinson disease patients had lower retinal capillary skeleton and perfusion densities and capillary complexity in the total annular zone and all quadrant sectors compared with healthy control subjects. The deep retinal capillary plexus retinal capillary complexity was decreased in the total annular zone and the superior and inferior quadrants. The retinal capillary complexity in the inferior quadrant was negatively correlated with the best-corrected visual acuity and disease duration (r = -0.61, r = -0.43, respectively, both P < 0.05). CONCLUSION: As determined by fractal analysis, retinal capillary complexity can be an objective biomarker in Parkinson disease.

Trio-based exome sequencing arrests de novo mutations in early-onset high myopia.

The etiology of the highly myopic condition has been unclear for decades. We investigated the genetic contributions to early-onset high myopia (EOHM), which is defined as having a refraction of less than or equal to -6 diopters before the age of 6, when children are less likely to be exposed to high educational pressures. Trios (two nonmyopic parents and one child) were examined to uncover pathogenic mutations using whole-exome sequencing. We identified parent-transmitted biallelic mutations or de novo mutations in as-yet-unknown or reported genes in 16 probands. Interestingly, an increased rate of de novo mutations was identified in the EOHM patients. Among the newly identified candidate genes, a BSG mutation was identified in one EOHM proband. Expanded screening of 1,040 patients found an additional four mutations in the same gene. Then, we generated Bsg mutant mice to further elucidate the functional impact of this gene and observed typical myopic phenotypes, including an elongated axial length. Using a trio-based exonic screening study in EOHM, we deciphered a prominent role for de novo mutations in EOHM patients without myopic parents. The discovery of a disease gene, BSG, provides insights into myopic development and its etiology, which expands our current understanding of high myopia and might be useful for future treatment and prevention.

Thickness changes in the corneal epithelium and Bowman's layer after overnight wear of silicone hydrogel contact lenses.

BACKGROUND: To investigate thickness changes in the corneal epithelium and Bowman's layer after overnight silicone hydrogel contact lens (CL) wear by using ultra-high resolution optical coherence tomography (UHROCT). METHODS: Eleven subjects without CL wearing history were recruited for this study. An UHROCT was used to measure the thickness of the epithelium (ET), Bowman's layer (BT), stroma (ST), and total cornea (CCT) at the center of both eyes. A silicone hydrogel CL was inserted in the right eye of each subject, and the fellow non-CL wearing left eye served as the control. The lens was inserted at 9:30 pm and removed at 8:00 am the next morning. The subjects were evaluated at 9:00 pm (baseline), 9:30 pm (lens insertion), 10:00 pm (before sleep), 7:00 am (waking), 7:30 am, and 8:00 am (lens removal). RESULTS: Compared to the lens insertion level, the ET of the lens-wearing eye increased by 5.73% at eye opening (P = 0.001). The ET of the non-CL wearing eye and the BT in both eyes did not change after overnight CL wear. Compared to baseline, the CCT of the lens-wearing eye increased by 2.87% upon waking (P = 0.003) and recovered 30 min later (P = 0.555). In contrast, compared to baseline, the CCT of the non-CL wearing eye did not increase upon waking (P = 0.105). CONCLUSIONS: By using UHROCT, we found that overnight CL wear induced different swelling responses in the various sublayers of the cornea. TRIAL REGISTRATION: Retrospectively registered. Registration number: ChiCTR1800015115 . Registered 07 March 2018.

Reliability of Entire Corneal Thickness Mapping in Normal Post-Laser in situ Keratomileusis and Keratoconus Eyes Using Long Scan Depth Spectral Domain Optical Coherence Tomography.

PURPOSE: To investigate the repeatability and reproducibility of mapping the entire corneal thickness using spectral domain optical coherence tomography (SD-OCT). METHODS: Thirty normal eyes, 30 post-laser in situ keratomileusis (LASIK) surgery eyes, and 30 keratoconus eyes were analyzed. A custom-built long scan depth SD-OCT device was used to obtain entire corneal images. Ten-millimeter-diameter corneal thickness maps were generated by an automated segmentation algorithm. Intraclass correlation coefficients of repeatability (ICC1) and reproducibility (ICC2), and coefficients of repeatability (CoR1) and reproducibility (CoR2), were calculated to quantify the precision and accuracy of corneal pachymetry measurements using the Bland-Altman method. RESULTS: For SD-OCT measurements in healthy subjects, CoR1 and CoR2 were less than 5.00 and 5.53 µm. ICC1 and ICC2 were more than 0.997 and 0.996. For SD-OCT measurements in LASIK patients, CoR1 and CoR2 were less than 5.09 and 5.34 µm. ICC1 and ICC2 were more than 0.997 and 0.996. For SD-OCT measurements in keratoconus patients, CoR1 and CoR2 were less than 11.57 and 10.92 µm. ICC1 and ICC2 were more than 0.995 and 0.996. CONCLUSIONS: The measurements of corneal pachymetric mapping by long scan depth SD-OCT can be assessed over the entire corneal area with good repeatability and reproducibility.

MACULAR MICROSTRUCTURAL FEATURES IN CHILDREN WITH TILTED DISK SYNDROME EVALUATED BY SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY.

PURPOSE: To assess macular microstructure in eyes with tilted disk syndrome (TDS) and determine the relationship between TDS foveal morphology and visual function. METHODS: Twenty-six TDS eyes from 19 children (aged 5∼15 years) with a spherical equivalent refraction (SER) of -3.1 ± 1.3 diopter (D) and 28 control eyes from 14 children (aged 7∼12 years) with a SER of -3.0 ± 0.7 D were recruited. Horizontal and vertical optical coherence tomography scans through the fovea produced images that were segmented into eight intraretinal layers. Thicknesses of the total retina and each layer were measured at the foveal center and 12 other macular locations: 500 µm, 1,000 µm, and 1,500 µm along the horizontal and vertical meridians. The relationships between TDS best correct visual acuity (BCVA) and the presence of photoreceptor inner/outer segment (IS/OS) junction line, IS/OS foveal bulge, and cone outer segment tip (COST) line were evaluated. RESULTS: The thickness of TDS central fovea, 218.94 ± 22.20 µm, was not significantly different from controls. The total retinal thickness in TDS eyes was thinner than controls at all peripheral locations (P < 0.05) except at 500 µm and 1,000 µm superiorly, and 1,500 µm temporally. Tilted disk syndrome intraretinal layer thicknesses in the nasal and inferior regions varied significantly from controls (P < 0.05). Only 80.7% and 23.1% of TDS eyes had a normal foveal bulge and continuous COST line, respectively, compared with 100% and 96.4% of controls. The BCVA of TDS eyes was similar whether or not the foveal bulge or COST line was abnormal. CONCLUSION: Differences in intraretinal layer thickness may be correlated with defective vision.

Anterior Segment Biometry of the Accommodating Intraocular Lens and its Relationship With the Amplitude of Accommodation.

OBJECTIVES: To evaluate the anterior segment biometry of the Tetraflex accommodating intraocular lens (AIOL) and the contribution of forward movement to the amplitude of accommodation (AMP). METHODS: Patients who underwent phacoemulsification with implantation of Tetraflex AIOLs and control nonaccommodating intraocular lenses were imaged by custom-built, long scan depth spectral-domain optical coherence tomography at relaxed and maximal accommodative states. Anterior segment biometry was performed and correlated with the clinical manifestation including AMP. RESULTS: Patients in the Tetraflex group showed better distance-corrected near visual acuity (logMAR 0.43±0.10 vs. logMAR 0.51±0.10, P<0.05) and greater AMP (1.99±0.58 diopters [D] vs. 1.59±0.45 D, P<0.05) compared with the control group. The measurement of the postoperative anterior chamber depth (ACD) during accommodation showed a forward movement of the AIOLs in 16 eyes (69.6%). Compared with the control group, a greater proportion of cases in the Tetraflex group experienced forward movement (χ test, P<0.001). The AMP in the AIOL group negatively correlated with changes in postoperative ACD during accommodation (r=-0.47, P<0.05), whereas AMP in the control group negatively correlated with postoperative pupil diameter (r=-0.57, P<0.05). CONCLUSIONS: The Tetraflex AIOLs seemed to have a tendency for forward movement; however, the slight forward axial shifts of the Tetraflex AIOL during natural accommodation may not produce a clinically relevant change in optical power.

THREE-DIMENSIONAL CHARACTERISTICS OF FOUR MACULAR INTRARETINAL LAYER THICKNESSES IN SYMPTOMATIC AND ASYMPTOMATIC CARRIERS OF G11778A MUTATION WITH LEBER'S HEREDITARY OPTIC NEUROPATHY.

PURPOSE: To characterize by spectral domain optical coherence tomography the three-dimensional thicknesses of four macular intraretinal layers in symptomatic and asymptomatic carriers of G11778A mutation with Leber's hereditary optic neuropathy. METHODS: Twenty-five eyes (7 symptomatic eyes and 18 asymptomatic eyes) of patients with Leber's hereditary optic neuropathy from one Chinese family and 16 normal eyes were enrolled. Macular radial scans by spectral domain optical coherence tomography and custom software produced intraretinal three-dimensional thickness maps. The macula was divided into nine regions, and each region included four intraretinal layers: nerve fiber layer, ganglion cell layer and inner plexiform layer, inner nuclear layer and outer plexiform layer, and the outer retinal layer. RESULTS: Nerve fiber layer in the symptomatic eyes was significantly thinner than in normal eyes for most of the macular regions; however in the asymptomatic eyes, it was increased in three regions. Ganglion cell layer and inner plexiform layers in all regions of symptomatic eyes were significant thinner than in asymptomatic eyes and controls. Inner nuclear layer and outer plexiform layers in six regions of symptomatic and asymptomatic eyes were significantly thicker than in controls. The outer retinal layer of asymptomatic eyes was thicker than in most control regions. CONCLUSION: Intraretinal thickness changes in asymptomatic patients could be prodromal events that indicate the imminent conversion to symptomatic patients with Leber's hereditary optic neuropathy.

Real-Time Measurement of Dynamic Changes of Anterior Segment Biometry and Wavefront Aberrations During Accommodation.

OBJECTIVES: To analyze the dynamic relationship between ocular geometrical structure and high-order aberrations (HOAs) in teal-time during accommodation of human eye. METHODS: A custom-built spectral domain optical coherence tomography (OCT) system with high-speed and ultra-long scan depth was used to image the anterior segment, whereas a Shack-Hartmann wavefront sensor was used to detect the whole-eye aberration. A Badal optometer with switched visual targets was integrated with this system to induce 0 and 3.00 D accommodative stimuli. Three young adult subjects were measured and the structural parameters of anterior segment were measured from OCT images and accommodative response and HOAs were calculated and exponentially fitted in real time during the accommodation. RESULTS: The dynamic process from nonaccommodation to 3.00 D accommodation results in reduced pupil diameter, shallower anterior chamber depth, and increased crystalline lens thickness. After an accommodative active time, the RMS of the HOAs changes sharply when an accommodative stimulus is introduced and then tends to be stable. The accommodative response time and velocity are characterized by fitted parameters. The individual differences of changing in HOAs between subjects can be explained by the different sign and changing tendency of certain terms of aberration coefficients in form of Zernike polynomials during the accommodation. CONCLUSIONS: Based on the integrated ocular measurement platform including OCT system and wavefront sensor, our research demonstrated how the morphology of the human anterior segment affect the aberration in real time during accommodation. The dynamic relationship between them helps us to deeply understand the mechanism of accommodation.

Intratumoral neutrophil granulocytes contribute to epithelial-mesenchymal transition in lung adenocarcinoma cells.

We previously demonstrated that haemoptysis as a prognostic factor in lung adenocarcinoma and haemoptysis was associated with severe vascular invasion and high circulating white blood cell count. Epithelial-mesenchymal transition (EMT) plays an important role in tumor invasion. We hypothesized there was some relationship between tumor-associated inflammatory cells, tumor invasion, EMT, and haemoptysis. Immunohistochemistry (IHC) was used to detect CD66b and E-cadherin expression in tumor tissue. By co-culture tumor cells with polymorphonuclear neutrophils (PMNs), the expressions of EMT markers were assessed by western blotting. TGF-ß1 concentrations in the supernatant and the migration activities of tumor cells were performed by ELISA and migration assays. Intratumoral CD66b(+) PMN expression was negatively associated with E-cadherin expression. Haemoptysis was significantly associated with neutrophil infiltration (OR = 4.25, 95 % CI 1.246-14.502). Neutrophils promoted EMT of tumor cells in vitro and enhanced the migration activity of tumor cells. In addition, TGF-ß1 was up-regulated and Smad4 translocated into nucleus, indicating that TGF-ß/Smad signaling pathway was initiated during the process. We indicated that lung adenocarcinoma with haemoptysis was associated with more PMN infiltration and PMNs promoted EMT, partly via TGF-ß/Smad signal pathway. This may provide mechanistic reasons for why haemoptysis was associated with poor outcome in lung adenocarcinoma.

Intratumoral polymorphonuclear granulocyte is associated with poor prognosis in squamous esophageal cancer by promoting epithelial-mesenchymal transition.

AIM: The role of polymorphonuclear granulocyte (PMN) infiltration in tumor remains unclear in esophageal cancer (EC). MATERIALS & METHODS: We conducted a retrospective study on consecutive patients with primary squamous EC. The potential roles of PMN infiltration into tumor nests were assessed by immunohistochemistry. The interactions of PMNs and tumor cells were investigated in an in vitro coculture system. RESULTS: Intratumoral PMN is an independent prognostic factor. PMN infiltration induces epithelial-mesenchymal transition of cancer cells with the initiation of TGF-ß/Smad signaling pathway. CONCLUSION: Our study demonstrates intratumoral PMN is an independent unfavorable predictor in squamous EC. PMN promotes cancer progression partly by its ability to induce epithelial-mesenchymal transition via TGF-ß/Smad signaling pathway.

Monitor corneal epithelial healing under bandage contact lens using ultrahigh-resolution optical coherence tomography after pterygium surgery.

OBJECTIVE: To monitor corneal epithelial healing under bandage contact lens (BCL) using ultrahigh-resolution optical coherence tomography (UHR-OCT) after pterygium surgery. METHODS: Thirty-nine eyes of 39 patients undergoing pterygium excision and conjunctival autografting were randomly allocated into 2 groups: 20 eyes were covered with silicone hydrogel BCLs at the end of surgery and 19 eyes served as a control. Ultrahigh-resolution optical coherence tomography scans of the cornea were performed sequentially at 1, 2, and 3 days, and then every other day until the end of re-epithelialization after surgery. Complete epithelial healing was verified with fluorescein staining examination after removal of BCLs. Postsurgery pain was evaluated using the visual analog scale. RESULTS: All BCLs were successfully fit without any contact lens-related complications. Ultrahigh-resolution optical coherence images clearly revealed the architectural features of postoperative cornea with BCL in situ and showed epithelial healing process. Ultrahigh-resolution optical coherence tomography imaging agreed with the fluorescein staining examinations in detecting corneal epithelial defect. Based on the assessment by UHR-OCT, the average time course of re-epithelialization in the BCL group was 3.9±1.2 days, whereas in the control group, it was 5.7±1.8 days (P=0.001). Visual analog scale scoring showed lower pain levels in the BCL group comparing with the control group at each point of time (all P<0.05). CONCLUSIONS: Ultrahigh-resolution optical coherence tomography is an excellent tool in monitoring corneal epithelial healing under BCLs and determining the appropriate time for lens removal. Silicone hydrogel BCL is recommended as an adjuvant therapy after pterygium surgery for its efficacy in improving re-epithelialization and postoperative comfort.

Fully automated biometry of in situ intraocular lenses using long scan depth spectral-domain optical coherence tomography.

PURPOSE: Spectral-domain optical coherence tomography (SD-OCT) was used to automatically measure accommodative biometric changes in the anterior segment of eyes implanted with an intraocular lens (IOL). The repeatability and reliability of the automated measurements were also evaluated. METHODS: Long scan depth SD-OCT was used to image the anterior segment of eyes implanted with IOLs. A fully automated algorithm was used to detect the boundaries of the cornea and IOL and yielded the measurements. The results included anterior segment dimensions in IOL eyes and the deflection of the IOLs. Automated measurements were validated in vitro and compared with the manual results in vivo on 15 cross-sectional images from patients with IOLs. Five eyes with five different types of IOLs, respectively, were enrolled to test the repeatability of the automated measurements during accommodation. RESULTS: Intraocular lens central thickness and anterior and posterior curvature radii measured by long scan depth SD-OCT in vitro and in a model eye matched well with those determined by a micrometer caliper and interferometer. In vivo, there was good correlation of the biometric data determined by automated and manual segmentations (P<0.05, r-value range: 0.635-0.997). There were no significant differences for any variable between the two measurements at each accommodative state (P>0.05). Anterior chamber depth and pupil diameter showed significant changes between the nonaccommodative and 2.5-D accommodative states (P<0.05), whereas the shape of the IOLs did not change significantly (P>0.05). CONCLUSIONS: The long scan depth SD-OCT with the automated algorithm was verified to have a great potential in studying accommodative biometric changes of the anterior segment in eyes with IOLs and IOL deflections.

Agreement of corneal epithelial profiles produced by automated segmentation of SD-OCT images having different optical resolutions.

OBJECTIVE: Using a custom-developed segmentation algorithm, agreement of corneal epithelial thickness profile measurements between two spectral domain optical coherence tomography (SD-OCT) systems was assessed. METHODS: Eighteen left eyes (18 subjects; mean±standard deviation; age, 23.2±0.9 years) were imaged twice on nonconsecutive days by a custom-built ultra-high resolution OCT (UHR-OCT) system and a commercial RTVue OCT system. A segmentation algorithm based on axial gradient information and a shortest path search was developed to measure corneal epithelial thickness profiles from the SD-OCT images. RESULTS: There was good correlation between the automated and manual segmentation positions of the epithelium. The epithelial thickness differences between automated and manual segmentations by the UHR-OCT and RTVue OCT systems were 0.4±0.3 µm and 1.1±0.5 µm, respectively. The intraclass correlation coefficients (ICCs) and coefficients of repeatability for repeated UHR-OCT measurements of epithelial thickness were 0.90±0.05 µm and 1.44±0.01 µm, respectively. For RTVue OCT, the ICCs and coefficients of repeatability were 0.88±0.04 µm and 2.16±0.01 µm, respectively. The epithelial thickness measured by RTVue OCT was 1.1±0.2 µm greater than that by UHR-OCT (P<0.05, paired t test), and ICC for the agreement between the 2 systems was 0.85±0.06. The average 95% limit of agreement was -1.67 to 3.79 µm. CONCLUSIONS: For images of different qualities from both SD-OCT systems, the custom-developed automated segmentation of the corneal epithelium had good repeatability for thickness profile measurements. The accurate and precise algorithm also demonstrated good agreement of epithelial thickness profile measurements between the two SD-OCT systems.

Automatic biometry of the anterior segment during accommodation imaged by optical coherence tomography.

OBJECTIVE: To test accuracy and repeatability of a software algorithm that performs automatic biometry of the anterior segment of the human eye imaged with long scan depth optical coherence tomography (OCT). METHODS: The ocular anterior segment imaging was performed with custom-built long scan depth OCT. An automatic software algorithm including boundary segmentation, image registration, and optical correction was developed for fast and reliable biometric measurements based on the OCT images. The boundary segmentation algorithm mainly used the gradient information of images and applied the shortest path search based on the dynamic programming to optimize the edge finding. The automatic algorithm was validated by comparison of the biometric dimensions between automatic and manual measurements and repeatability study. RESULTS: Biometric dimensions of the anterior segment, including central corneal thickness, anterior chamber depth, pupil diameter, crystalline lens thickness, and radii of curvature of the anterior and posterior surfaces of lens, were obtained by the automatic algorithm successfully. There were no significant differences between the automatic and manual measurements for all biometric dimensions. The intraclass correlation coefficients (ICC) of agreement between automatic and manual measurements ranged from 0.85 to 0.98. The coefficients of repeatability and ICC for all automatic dimensions were satisfactory (1.1%-6.1% and 0.663-0.990, respectively). CONCLUSIONS: The high accuracy, good repeatability, and fast execution speed for automatic measurement of the anterior segment dimensions on the OCT images were demonstrated. The application of this automatic biometry is promising for investigating dynamic changes of human anterior segment during accommodation in real time.