Stromal Thickness Research Articles

Quantification of Iris Atrophy by Swept-Source Optical Coherence Tomography in Posner-Schlossman Syndrome.

Purpose: To investigate iris atrophy in Posner−Schlossman syndrome (PSS). Methods: Sixty-one patients with PSS were included. Using swept-source optical coherence tomography, the thickness of anterior border layer (A), middle stromal layer (M), and the posterior pigmented epithelial layer (P) of iris were measured at 500 μm, 1000 μm, 1500 μm, 2000 μm, and 2500 μm from the pupillary edge in both PSS-affected and fellow eyes. The relationships between iris thickness and corneal endothelium density, cup-to-disc (C/D) ratio, and retinal nerve fiber layer (RNFL) thickness were also estimated in PSS-affected eyes. Results: Iris thickness parameters, including M500, M1000, A1500, A2000, P2000, and P2500, were significantly thinner in PSS-affected eyes than in fellow eyes (all p < 0.05). Moreover, M500 and M1000 were significantly associated with corneal endothelium density (p = 0.047 and 0.018, respectively), and M500 was significantly associated with C/D ratio (p = 0.001) and RNFL thickness (p = 0.037) in PSS-affected eyes. Conclusions: Iris showed significant thinning and atrophy in PSS-affected eyes, and iris stromal thickness close to the pupillary edge could be a novel clinical predictor of the changes in corneal endothelium, C/D ratio, and RNFL thickness in PSS.

The Prognostic Significance of the Depth of Cervical Stromal Invasion in Women with FIGO Stage II Uterine Endometrioid Carcinoma

<h3>Purpose/Objective(s)</h3> To explore the prognostic significance of the depth of cervical stromal invasion (CSI) on survival endpoints in women with FIGO stage II uterine endometrioid adenocarcinoma. <h3>Materials/Methods</h3> A total of 117 patients were included in this retrospective review. Between 1990 and 2021, all patients with FIGO stage II endometrial cancer (EC) underwent hysterectomy and oophorectomy at our institution, with or without lymph node dissection. Patients with synchronous ovarian or breast cancer, as well as those who had undergone adjuvant systemic chemotherapy for EC, were excluded from the study. Pathologic slides were retrieved for these patients and were reviewed by a gynecologic pathologist to determine stromal thickness and the depth of CSI. The depth of CSI was then measured as a percentage of invasion (% CSI) and used in the analysis as a continuous or dichotomous variable (< 50% vs > = 50%). Patients' demographics, pathologic, and treatment characteristics were analyzed using univariate and multivariate analysis to calculate recurrence-free (RFS) and disease-specific (DSS) rates. <h3>Results</h3> The median age for the study cohort was 65 years (range, 34–96), and the median follow-up was 131 months (range, 9–334). A total of 90 patients (77%) had lymph node dissection, with a median of 8 examined lymph nodes (range 0-18). Adjuvant radiation therapy (RT) with pelvic or vaginal cuff HDR brachytherapy, or a combination of the two, was completed in 92 patients (79 percent). The median % CSI was 27% (range, 1-100) with 68% of patients having ≥ 50% CSI. While there was a trend for a worse 5-year RFS and DSS for women with ≥ 50% CSI (69% vs. 83%, p = 0.093) and (78% vs. 91%, p = 0.034), respectively, the depth of CSI was not statistically significant as an independent predictor of 5-year RFS, DSS, or OS. The depth of CSI was not associated with a difference in the recurrence pattern (vaginal cuff, pelvic, paraaortic, or distant). In multivariate analysis, FIGO grade was the only predictor of 5-year OS. FIGO grade and the presence of lympho-vascular space invasion (LVSI) were independent predictors of 5-year RFS and DSS. <h3>Conclusion</h3> Deep cervical stromal invasion does not appear to be an independent predictive factor for survival endpoints in women with stage II uterine endometroid cancer, according to our findings. The presence of LVSI and tumor grade were both independent predictors of recurrence-free and disease-specific survival. Pooled data analysis may be needed to validate our study findings.

Исследование частоты встречаемости клинически тонкой роговицы у пациентов с миопией средней и высокой степени, обратившихся для выполнения кераторефракционной операции

Purpose. To assess frequency of occurrence patients with insufficient thickness of optical zone of cornea for complete elimination of myopic refraction using FemtoLASIK technology. Material and methods. By random sampling, 100 patients (200 eyes) were selected with varying degrees of myopia who planned refractive surgery using the FemtoLASIK or Smile technology. The selection criterion was presence the prognosis of residual myopia in eyes due to the inability to fulfill the required ablation depth of the optical zone. The share of such patients in the total population of selected patients, their gender, age, magnitude of residual myopic refraction were found out. Results. According to results of the study in 88 patients (176 eyes, 88 %) thickness of optical zone of cornea made it possible to completely eliminate the existing myopic refraction) using the FemtoLASIK or Smile technology. In 12 patients (24 eyes, 12 %) thickness of optical zone of cornea did not made it possible to completely eliminate myopic refraction, without critical thinning of the stromal bed of cornea. The predicted residual myopia in these eyes ranged from –1.0 to –2.5 diopters. Photorefractive keratectomy technology was offered to these patients, which was agreed by 8 patients (16 eyes). Conclusion. The obtained data revealed the high relevance of the development of femtolaser refractive surgery technology, which provides for the complete elimination of myopic refraction in such patients by reducing the thickness of the corneal surface valve and, accordingly, increasing the thickness of the stromal bed. Keywords: refractive surgery, residual myopia, ablation depth, FemtoLASIK, corneal surface valve, residual stromal bed thickness.

Фоторефрактивная кератэктомия как приоритетный метод докоррекции остаточных аметропий

Purpose. To show the effectiveness and safety of the correction of residual ametropia by the PRK method after previously performed keratorefractive operations LASIK, FemtoLASIK, ReLEx SMILE. Material and methods. All patients were divided into 3 groups: Group 1 – previously performed LASIK surgery with insufficient stroma thickness under the valve and patients with unknown parameters of the corneal flap operated in third-party clinics 35 patients (50 eyes), age 46.3 ± 21.9 years, the value of the spherical equivalent – 2.41 ± 1.45. Group 2 – patients after femtolasik 6 patients (6 eyes), age 30 ± 8.3 years, spherical equivalent value – 1.83 ± 0.76. Group 3 – patients after ReLExSMILE 8 patients (11 eyes), age 33 ± 4.4 years, spherical equivalent value – 0.88 ± 0.66. The minimum period after the initial keratorefractive surgery was 1 year, the maximum follow-up period was 4 years. Results. When analyzing the results 6 months after the operation of photorefractive keratectomy: group 1 – the value of the spherical equivalent – 0.26 ± 0.46; group 2 – 0.11 ± 0.2; group 3 – 0.19 ± 0.34. In Group 1, 4 patients (5 eyes) had a loss of lines (3 patients (4 eyes) – 1 line, 1 patient (1 eye) – 2 lines) of maximum visual acuity, all other patients had UDVA to CDVA before the operation of PRK. In groups 2 and 3, the maximum figures of visual acuity were taught. Conclusions. The use of transepithelial photorefractive keratectomy allows to obtain high clinical and functional results, is a safe, easy-to-perform, universal and highly effective method of correcting residual ametropias after various previously performed keratorefractive operations. Keywords: PRK, PRK after LASIK, PRK after FemtoLASIK, PRK after SMILE.

Рибофлавин в профилактике фиброплазии в лазерной рефракционной хирургии роговицы

Purpose: To substantiate the use of riboflavin for the prevention of subepithelial and intrastromal fibroplasia in laser refractive corneal surgery. Material and methods: The work is based on 9-year clinical observations of the results of photorefractive and phototherapeutic corneal surgery with stroma saturation with riboflavin (more than 700 operations). Keratoablation was performed after drip, aerosol or combined saturation of the stroma with 0.1 % or 0.25 % chilled isotonic riboflavin solution. Corneal OCT was performed on RTVue 100 and RTVue XR100 devices. Keratotopographic and densitometric studies were performed on a TMS-5 instrument. These devices were used with two-wavelength optical scanning in the visible green and infrared ranges to assess prophylactic crosslinking by the change in the refractive index of the cornea. Results: During photokeratoablation, corneal stroma layers saturated with riboflavin acted as spectral filters, protecting keratocytes from secondary radiation induced by ablation. This reduced the response of aseptic inflammatory and regenerative reactions, the severity and duration of the corneal syndrome. According to OCT and corneal densitometry data, the formation of a Bowman-like structure on the ablation surface was noted with an increase in optical density in the underlying layers of the stroma. Two-wavelength optical scanning revealed a significant increase in the refractive index. The effect of laser-induced crosslinking and the increase in optical density had a damped character and did not exceed 1/2 of the stroma thickness. These changes in the cornea were a barrier between pro-inflammatory epithelial and stromal cytokines that stimulate the development of subepithelial and intrastromal fibroplasia after photokeratoablation. Conclusion. During photokeratoablation, riboflavin-saturated layers of the corneal stroma protect deeper-lying keratocytes from secondary radiation induced by ablation, and the formation of a Bowman-like structure on the ablation surface with a damping effect of crosslinking in the superficial layers of the stroma prevents the development of fibroplasia. Keywords: Riboflavin, Mitomycin-C, fibroplasia, photoablation, excimer laser corneal surgery, laser-induced crosslinking.

Corneal aberrations, densitometry on scheimpflug imaging, and visual acuity after deep anterior lamellar keratoplasty.

To evaluate visual acuity, corneal aberrations, and densitometry post deep anterior lamellar keratoplasty (DALK). Twenty-five eyes of 25 patients who underwent DALK for corneal stromal diseases with normal endothelium were enrolled in a prospective interventional study. Evaluation for corneal aberrations and densitometry postoperatively was performed using Scheimpflug imaging at 6 months. Anterior Segment Optical Coherence Tomography (ASOCT) was done for host-graft morphology. Correlation analysis of postoperative best-corrected visual acuity with corneal aberrations and corneal densitometry (CD) was performed. Big bubble deep anterior lamellar keratoplasty (BB-DALK) was successful in 18 patients, while 7 eyes underwent manual dissection due to failed BB (Big Bubble) technique. The mean BSCVA was 1.35 ± 0.46 logMAR units pre-operatively which improved to 0.36 ± 0.19 logMAR units post DALK at 6 months (P < 0.001). The mean Root Mean Square (RMS) (μm) of the magnitude of total corneal aberrations, HOA and LOA from central 6mm zone of cornea were 14.6 ± 9.2, 4.7 ± 2.9, and 13.8 ± 8.8, respectively. The mean anterior (120μm), central and posterior corneal (60μm) densitometry in 0-2mm zone were 25.8 ± 7.7 GSU, 18.7 ± 4.16 GSU and 10.09 ± 3.9 GSU respectively. A statistically significant correlation of postoperative residual stromal bed thickness, total corneal HOA, LOA, total corneal aberrations, HOA front and posterior corneal densitometry (0-2mm zone) with postoperative BSCVA was found. Though there is a significant improvement in BSCVA after DALK, the quality of vision in terms of aberrometry and densitometry is suboptimal, especially in cases undergoing manual DALK compared to those undergoing big bubble formation.

Two-year stability of posterior corneal surface after transepithelial photorefractive keratectomy with a residual stromal thickness less than 350μm.

This study aimed to investigate the stability of posterior corneal surface 2years after transepithelial photorefractive keratectomy (TPRK) in patients with a residual stromal thickness less than 350μm. In total, 408 eyes of 212 patients (160 women, 52 men) who underwent TPRK were enrolled in this retrospective study. All surgeries were performed in the Amaris 750S excimer laser platform with smart pulse technology. The posterior corneal elevation, anterior chamber depth, Q value, and curvature were measured using Pentacam preoperatively and postoperatively. All patients were followed up for 2years. The relationship between percent tissue altered (PTA), age, and changes in posterior corneal surface was analyzed. The mean preoperative spherical equivalent was - 6.80 ± 1.18 D (range: - 9.00 to - 2.63 D). The mean residual stromal thickness was 336.46 ± 7.25μm (range: 310-348μm). The mean PTA was 30.93 ± 2.03% (range: 24.29-35.28%). At 2years after surgery, the elevation of six points in the central area decreased by 1.91 ± 2.97μm, 2.98 ± 3.23μm, 1.17 ± 3.85μm, 1.70 ± 2.88μm, 1.36 ± 3.19μm, and 1.65 ± 3.18μm, compared with the preoperative value (P < 0.05). The elevation of three points in the peripheral area increased by 1.87 ± 6.34μm, 0.68 ± 6.00μm, and 0.95 ± 5.50μm (P < 0.05). There was no significant linear relationship between PTA, age, and changes in posterior corneal surface, anterior chamber depth, and K2 (all P > 0.05). Within 2years after TPRK, the posterior corneal surface remained stable in patients with a residual stromal thickness between 310 and 350μm. There was no sign of iatrogenic ectasia during the follow-up period.

Time-dependent in situ structural and cellular aberrations in rabbit cornea in vivo after mustard gas exposure

An array of corneal pathologies collectively called mustard gas keratopathy (MGK) resulting from ocular exposure to sulfur mustard (SM) gas are the most prevalent chemical warfare injury. MGK involves chronic ocular discomfort that results in vision impairment. The etiology of MGK remains unclear and poorly understood primarily due to a lack of scientific data regarding structural and cellular changes in different layers of the cornea altered by mustard vapor exposure in vivo. The goals of this study were to (a) characterize time-dependent changes in different layers of corneal epithelium, stroma, and endothelium in live animals in situ by employing state-of-the-art multimodal clinical ophthalmic imaging techniques and (b) determine if SM-induced acute changes in corneal cells could be rescued by a topical eye drop (TED) treatment using in an established rabbit in vivo model. Forty-five New Zealand White Rabbit eyes were divided into four groups (Naïve, TED, SM, and SM + TED). Only one eye was exposed to SM (200 mg-min/m3 for 8 min), and each group had three time points with six eyes each (Table-1). TED was topically applied twice a day for seven days. Clinical eye examinations and imaging were performed in live rabbits with stereo, Slit-lamp, HRT-RCM3, and Spectralis microscopy system. Fantes grading, fluorescein staining, Schirmer's tests, and applanation tonometry were conducted to measure corneal haze, ocular surface aberrations, tears, and intraocular pressure respectively. H&E and PSR staining were used for histopathological cellular changes in the cornea. In vivo confocal and OCT imaging revealed significant changes in structural and morphological appearance of corneal epithelium, stroma, and endothelium in vivo in SM-exposed rabbit corneas in a time-dependent manner compared to naïve cornea. Also, SM-exposed eyes showed loss of corneal transparency characterized by increased stromal thickness and light-scattering myofibroblasts or activated keratocytes, representing haze formation in the cornea. Neither naive nor TED-alone treated eyes showed any structural, cellular, and functional abnormalities. Topical TED treatment significantly reduced SM-induced abnormalities in primary corneal layers. We conclude that structural and cellular changes in primary corneal layers are early pathological events contributing to MGK in vivo, and efficient targeting of them with suitable agents has the potential to mitigate SM ocular injury.

Effects of SMILE with different residual stromal thicknesses on corneal biomechanical properties of rabbits in vivo

Femtosecond laser small incision lenticule extraction (SMILE) with different residual stromal thicknesses (RST) is set to investigate its effect on corneal biomechanical properties of rabbits in vivo. In this study, 24 healthy adult Japanese rabbits were randomly divided into group A and B. The RST of group A was set 30% of the corneal central thickness (CCT), and the RST of group B was 50% of the CCT. The thickness of the corneal cap in both groups was set one third of CCT. Corneal visualization Scheimpflug technology (Corvis ST) and Pentacam three-dimensional anterior segment analyzer were used to determine corneal biomechanical and morphological parameters before surgery, and 1 week, 1 month and 3 months after surgery. Pearson correlation analysis was used to analyze factors affecting corneal biomechanical parameters after SMILE. The results showed that the corneal stiffness of group A was significantly higher than that of group B at 1 week and 1 month after surgery, and most biomechanical parameters returned to preoperative levels at 3 months postoperatively. The results of correlation analysis showed that postoperative CCT and RST were the main factors affecting corneal biomechanical parameters after SMILE. There was no significant difference in corneal posterior surface height (PE) between 3 months after surgery and before surgery in both two groups. It indicates that although the ability to resist deformation of cornea decreases in SMILE with thicker corneal cap and less RST, there is no tendency to keratoconus, which may be related to the preservation of more anterior stromal layer.

Corneal epithelial remodeling after femtosecond laser-assisted in situ keratomileusis combined with intraoperative accelerated corneal collagen crosslinking for myopia: a retrospective study

BackgroundThis study analyzed regional corneal thickness remodeling, biomechanical properties, and visual outcomes after femtosecond laser-assisted in situ keratomileusis combined with intraoperative accelerated corneal collagen crosslinking (LASIK Xtra) for myopia.MethodsThis retrospective study analyzed 21 consecutive patients (18 women, three men; 42 eyes) who were treated with LASIK Xtra. All treatments were performed with ultraviolet-A (energy, 2.7 J/cm2; irradiance, 30 mW/cm2), using continuous (90 s) illumination. Postoperative values of corneal biometrics and visual outcomes were compared with preoperative values. Corneal thickness changes were evaluated using anterior segment optical coherence tomography. All patients were followed up for 12-month postoperatively. Preoperative and postoperative data were compared statistically using the paired t-test for normally distributed parameters and the Wilcoxon rank-sum test and Friedman analysis of variance with Bonferroni correction for non-normally distributed data.ResultsUncorrected distance visual acuity (UDVA) significantly improved at 6-month after surgery (P < 0.001). The central and inner regional corneal epithelial thickness significantly increased after LASIK Xtra (P < 0.05 for all), while the peripheral corneal epithelial thickness remained stable at 12-month after surgery. There was also a statistically significant decreased in the stromal thickness at most locations (P < 0.05 for all), except in the outer superior and outer superior-temporal regions.ConclusionsLASIK Xtra provided improvement in UDVA, corneal curvature, and corneal biomechanical stability. Because the results of this retrospective study results depended on the cohort members’ past information, it was inferred and confirmed that regular corneal thickness remodeling occurred after treatment.

Novel detection of stem cell niche within the stroma of limbus in the rabbit during postnatal development

Identifying and locating stem cell populations in the limbus may lead to developing a cell-based strategy for treating the corneal injury. Therefore, this study was the first to design a follow-up on the microscopical and histomorphometric changes in the rabbit limbus and to localize and demonstrate the limbal stem cell niche during postnatal development. The paraffin sections from the eyes of different postnatal-developmental stages were stained and examined using light microscopy. Furthermore, sections were immunohistologically stained for the epithelial stem cell differentiation marker, cytokeratin-14. Moreover, semithin and ultrathin sections were applied for ultrastructural demonstration of the stem cell niche. This study revealed that the number and thickness of limbal epithelial layers increased with age, whereas the thickness of limbal stroma decreased. Additionally, the immunohistochemical data showed that ck14 staining intensity increased in the limbal region where limbal stem cells reside. The semithin and ultrastructure investigation revealed stem cell clusters within the limbus’s underlying stroma close to the blood and nerve supply and surrounded by telocytes. Conclusively, isolated clusters of limbal epithelial stem cells combined with blood vessels, nerve fibers, and telocytes propose a harmonious microenvironment of a stem cell niche.

Monolateral Epithelial Hyperplasia Caused by Boiling Oil Misdiagnosed as Unilateral Keratoconus

PURPOSE: To describe a case of monolateral decreased visual acuity due to corneal epithelial hyperplasia that occurred after a thermal burn. A surgical approach can restore visual acuity and the corneal surface regularity. METHODS: The patient was concerned about a decrease in visual acuity. The slit-lamp examination and general medical history were not significant. The diagnosis was achieved by performing an anterior segment tomography, which showed an increased epithelial thickness with a reduced stromal thickness. No pathological anterior or posterior elevation areas were detected. Corneal biomechanics evaluation confirmed the absence of keratoconus. After further interrogation, the patient recalled she had a domestic mild thermal burn with boiling oil. RESULTS: The patient underwent a corneal epithelial debridement and achieved an uncorrected distance visual acuity of 20/20. CONCLUSIONS: The authors highlight the importance of performing anterior segment tomography and of studying the epithelial thickness after corneal burns, even in clear corneas. [ Journal of Refractive Surgery Case Reports. 2022;2(3):e55–e59.]

Evaluating Depth and Width of Corneal Wounds Using Anterior Segment Optical Coherence Tomography After Foreign Body Removal

ABSTRACTPurposeTo determine corneal foreign body (FB) location together with corneal wound depth and width by using anterior segment optical coherence tomography (AS-OCT) after uncomplicated FB removal.MethodThis prospective study was conducted with patients injured by a superficial metallic corneal FB. Under slit-lamp examination, after determining its location, the FB was removed with a 27-G needle. The depth and width of the corneal wound and the thinnest stromal thickness at the wound site were measured initially using AS-OCT. Measurements were repeated to assess the wound healing process at one week and at two months following FB removal.ResultsTotally, 63 eyes of 63 patients were included in this study. The average age was 35.8 ± 11.0 years, and 96.8% of the patients were men. In terms of location of the FBs, 26 (41.3%) were in the central region, 21 (33.3%) were in the paracentral region, and 16 (25.4%) were in peripheral regions. The mean depth and width of the corneal wounds were 117.0 ± 42.5 µm and 332.9 ± 99.4 µm, respectively. The mean percentage of corneal wound depth was 18.9 ± 6.1%. In 20 patients who presented for follow-up, it was observed that the width of the wound increased and the thinnest stromal thickness at the wound site decreased over the two months.ConclusionThe AS-OCT findings of the present study showed that the corneal FBs generally affected the anterior cornea with less than approximately 0.2 mm depth and 0.5 mm width. In addition, FBs were commonly located in the central and paracentral cornea.

Anterior segment-optical coherence tomography and diabetic retinopathy: Could it be an early biomarker?

IntroductionTo measure the corneal thickness (CT), corneal epithelial thickness (CET), and corneal stromal thickness (CST) in patients affected by type 2 diabetes mellitus with good glycemic control and without any signs of diabetic retinopathy using anterior-segment optical coherence tomography (AS-OCT). Methods60 eyes of 30 diabetic patients and 60 normal eyes of 30 healthy subjects underwent AS-OCT, evaluation of best-corrected visual acuity (BCVA), intraocular pressure (IOP), slit-lamp biomicroscopy, tear film breakup time (TBUT), Schirmer I test and fundus examination. The CT, CET, and CST maps generated corresponded to a 6-mm diameter area of the cornea that was divided into 17 sectors. We compared the CT, CET, and the CST of each sector obtained in the diabetic group with those obtained in the control group. ResultsNo significant difference in terms of age, gender, BCVA, IOP, TBUT, and Schirmer I test between the two study groups was observed. The CT, CET, and CST in the central section were significantly thickened in diabetic patients than in controls (p<0.001). Also, each paracentral and midperipheral sector was significantly increased in patients compared to controls (p<0.05). ConclusionsThe evaluation of the CT, CET, and CST by AS-OCT could be a valid and non-invasive biomarker in patients effected by diabetes mellitus, useful in early diagnosis of diabetic retinopathy.

Iridian anterior segment OCT in rubella uveitis syndrome and cytomegalovirus anterior uveitis: a comparative study.

To compare iris affectation in cytomegalovirus anterior uveitis (CMVAU), rubella virus-associated uveitis (RVU), and healthy contralateral eyes, using swept-source anterior segment optical coherence tomography (SS-AS-OCT). A comparative, transversal, retrospective study examining 60 eyes from 30 patients-18 eyes (17 patients) with CMVAU, 14 eyes (13 patients) with RVU, and 28 healthy eyes-was performed. Six-millimeter cross-sectional SS-AS-OCT B-scans were obtained in each iris quadrant. Images were exported to ImageJ®. Qualitative and quantitative analyses were done: stromal thickness (ST), smooth index (SI), and optical density (OD) of pigment epithelium. Comparisons between measurements and clinical-demographic parameters were performed using SPSS®. Qualitative analysis showed extensive damage in iris stroma but was unable to differentiate between both uveitis. RVU eyes had a lower mean ST (315.72μm ± 42.4) compared to those with CMVAU (348.6μm ± 46) (p = 0.047) and a lower ST in the upper (338.9μm ± 38.52)/(386.25μm ± 47.2) (p = 0.005) and temporal (281.5μm ± 57.3)/(326.43μm ± 62.3) (p = 0.016) quadrants. Mean (0.94 ± 0.02)/(0.9 ± 0.03) (p = 0.001), temporal (0.94 ± 0.02)/(0.89 ± 0.03) (p < 0.001), and nasal SI (0.094 ± 0.02)/(0.9 ± 0.04) (p = 0.005) were higher in RVU. OD was similar in both uveitis. In healthy eyes, mean ST (376.8μm ± 39.7) was higher and mean SI was lower (0.87 ± 0.04) than in RVU (p < 0.001) and CMVAU eyes (p = 0.032). Mean OD was higher in healthy eyes (911 ± 130) than in CMVAU eyes (800 ± 200) (p = 0.037). The quantitative analysis of the SS-AS-OCT iris images allows for the differentiation between healthy eyes and those with CMVAU and RVU, as well as between both uveitis.

Dynamic Contrast Microscopic Optical Coherence Tomography As a Novel Method for Assessing Corneal Epithelium During Exposure to Benzalkonium Chloride.

PurposeMicroscopic optical coherence tomography (mOCT) has an imaging resolution of 1 µm in all voxel dimensions, but individual epithelial cells are difficult to resolve due to lack of scattering contrast. Adding dynamic contrast processing to mOCT (dmOCT) results in color images that enable visualization of individual cells and possibly give information on cellular function via the calculation of a motility coefficient. We propose this technique as a novel method of evaluating the ocular surface after exposure to a toxic chemical, benzalkonium chloride (BAK).MethodsEx vivo cross-section images were acquired with a custom-built, frequency-domain mOCT system. Eyes were explanted from healthy adult C57BL/6 mice and imaged every 30 minutes with five sets of dmOCT scans at each imaging time. Total epithelium and stroma thicknesses were measured from a single mOCT B-scan, and measures of color changes (hue) and the motility coefficient were acquired from dmOCT scans.ResultsAfter 30-minute exposures to 0.005% BAK, local motility decreased and total epithelium thickness increased compared to controls. For basal epithelium cells, local motility decreased after 60-minute exposures, and the hue shifted red after 90-minute exposures. Stroma thickness did not significantly swell until 150-minute exposures to BAK.ConclusionsdmOCT allows us to view the behavior of the cornea epithelium under toxic stress due to BAK, revealing parallel swelling of the extracellular matrix and changes in local subcellular motion.Translational RelevanceThe evaluation of the cornea epithelium using dmOCT is helpful to our understanding of the toxic effects of BAK.

Comparison of stromal thickness and doppler findings in polycystic ovary syndrome and healthy women with ultrasonographic evidence of polycystic ovaries? A cross-sectional study

The purpose of the study was to compare the ovarian stromal blood flow and stromal thickness (ST) of polycystic ovary syndrome (PCOS) patients, with healthy women with polycystic ovarian morphology (PCOM) and normal ovarian morphology (NOM). A total of 220 participants were recruited and the three study groups were determined by diagnostic criteria (PCOS n = 106, PCOM n = 68, NOM n = 46). Clinical, hormonal and ultrasonographic measurements of ovaries were assessed and compared. PCOS patients showed statistically higher androgen levels, insulin resistance, hirsutism score, ovarian ST and stromal blood flow compared to PCOM and NOM. The correlation between free androgen index (FAI) and ST was measured. FAI was significantly highly correlated with left ovarian ST (0.83; p < .001) and right ovarian ST (0.83; p < .001). According to the results of this study, the ovarian ST which can be considered as ultrasonographic indicator of FAI, can be used in PCOS diagnosis. Also, it can be suggested that there is no statistically significant difference in ovarian ST and doppler findings between healthy women with PCOM or NOM. ROC analysis was used to measure diagnostic utility of ST. Impact Statement What is already known on this subject? Although it is known that ovarian stromal blood flows and stromal thickness are increased in PCOS disease compared to healthy women, they are not included in the diagnostic criteria. What the results of this study add? In the results of this study, it was determined that ovarian stromal blood flow and stromal thickness were increased in PCOS patients, as previously reported in the literature. In addition, these ultrasound measurements were found to be increased in PCOS patients compared to healthy women with PCO morphology, and stromal thickness measurements were strongly correlated with the free androgen index in PCOS patients. What the implications are of these findings for clinical practice and/or further research? Ovarian ST and/or S/A ratio may be an ultrasonograpic indicator of FAI, and may be used in PCOS diagnostic criterias. In the future, it can be revealed whether they vary in patients with different components of the syndrome, by examining these parameters in different PCOS phenotypes.

Applying Information Gain to Explore Factors Affecting Small-Incision Lenticule Extraction: A Multicenter Retrospective Study.

PurposeThis retrospective study aimed to identify the key factors influencing postoperative refraction after small-incision lenticule extraction (SMILE) using information gain.MethodsThis study comprised 2,350 eyes of 1,200 patients who underwent SMILE using a Visumax 500-kHz femtosecond laser (Carl Zeiss Meditec AG) in three ophthalmic centers: Tianjin Eye Hospital (center A), Jinan Mingshui Eye Hospital (center B), and Qingdao Eye Hospital (center C). Anterior segment features, including corneal curvature and central corneal thickness (CCT), were obtained from Pentacam HR (Oculus, Wetzlar, Germany). Information gain was calculated to analyze the importance of features affecting postoperative refraction.ResultsPreoperative and postoperative mean spherical equivalent (SE) refraction were −5.00 (−6.13, −3.88) D and 0.00 (−0.25, 0.13) D, respectively. None of the patients lost more than two lines of corrected distance visual acuity. The safety index was 1.32 ± 0.24, 1.03 ± 0.08, and 1.13 ± 0.16 in centers A, B, and C, respectively. The efficacy index was 1.31 ± 0.25, 1.02 ± 0.08, and 1.13 ± 0.17 in centers A, B, and C, respectively. At least 95% of the eyes were within ±1.00 D of the attempted correction. Postoperative refraction was related to preoperative spherical diopter refraction (r = 0.369, p < 0.001), preoperative SE (r = 0.364, p < 0.001), maximum lenticule thickness (r = −0.311, p < 0.001), preoperative uncorrected distance visual acuity (r = 0.164, p < 0.001), residual stromal thickness (r = 0.139, p < 0.001), preoperative mean anterior corneal curvature (r = −0.127, p < 0.001), preoperative flattest anterior corneal curvature (r = −0.122, p < 0.001), nomogram (r = −0.100, p < 0.001) and preoperative CCT (r = −0.058, p = 0.005).ConclusionsSMILE was considered a safe and effective procedure for correcting myopia. Based on information gain, postoperative refraction was influenced by preoperative mean anterior corneal curvature, CCT, refraction, and residual stromal thickness.

Small Incision Lenticule Extraction (SMILE) for the Correction of High Myopia With Astigmatism.

To report the outcomes of small incision lenticule extraction (SMILE) for high myopia between -9.00 and -14.00 diopters (D). This was a prospective study of SMILE for high myopia using the VisuMax femtosecond laser (Carl Zeiss Meditec). Inclusion criteria were attempted spherical equivalent refraction (SEQ) between -9.00 and -14.00 D, cylinder up to 7.00 D, corrected distance visual acuity (CDVA) of 20/40 or better, age 21 years or older, and suitable for SMILE. The sub-lenticule thickness was 220 µm or greater, and the total uncut stromal thickness was 300 µm or greater. Patients were to be followed up for 1 year. Standard outcomes analysis was performed using 12-month data where available or 3-month data otherwise. Of 187 eyes treated, data were available at 12 months for 181 eyes (96.8%) and 3 months for 4 eyes (2.1%), and 2 eyes (1.1%) were lost to follow-up. Mean attempted SEQ was -10.55 ± 1.00 D (range: -9.00 to -12.99 D). Mean cylinder was -1.19 ± 0.83 D (range: 0.00 to -4.00 D). Preoperative CDVA was 20/20 or better in 73% of eyes. Postoperative uncorrected distance visual acuity was 20/20 or better in 57% and 20/25 or better in 82% of eyes. Mean SEQ relative to target was -0.22 ± 0.48 D (range: -1.63 to +1.38 D), 66% ± 0.50 D and 93% ±1.00 D. Mean SEQ 12-month change was -0.08 ± 0.34 D (range: -1.75 to +0.88 D). There was loss of one line of CDVA in 4% of eyes, and no eyes lost two or more lines. Contrast sensitivity was unchanged. Patient satisfaction was 8 or more out of 10 in 94% and 6 or more in 99% of patients. Outcomes of SMILE for myopia greater than -9.00 D at 3 to 12 months showed excellent efficacy, safety, stability, and predictability, with high patient satisfaction. [J Refract Surg. 2022;38(5):262-271.].

Predictive factors of posterior corneal shift aftersmall incision lenticule extraction: a 5-year follow-up study.

The aim of this study was to determine risk factors affecting changes in posterior corneal elevation (PCE) and predict the 5-year stability after small incision lenticule extraction (SMILE). This retrospective, longitudinal study enrolled 161 patients post-SMILE. The PCE values were measured at the apex, thinnest, maximal and 24 other prespecified preoperative points and at 6 months, 1 year and 5 years postoperatively. Posterior corneas exhibited time-dependent, region-dependent and angle-dependent changes. For every dioptre increase in the absolute preoperative spherical equivalent (SE), 10-μm decrease in the central corneal thickness (CCT), 10-μm increase in the maximum lenticule thickness (MLT), 10-μm decrease in the residual bed thickness (RBT), 10% increase in the percentage ablation depth (PAD, MLT divided by CCT) and 10% decrease in the percentage stromal bed thickness (PSBT, RBT divided by CCT), PCE exhibited average forward displacements of 0.2-0.4, 0.2-0.7, 0.1-0.2, 0.1-0.3, 0.6-1.0 and 0.5-1.1 μm, respectively (p < 0.05). PSBT was the variable with the highest accuracy in predicting 5-year stability of posterior corneas (area under curve = 0.75). The cut-off values of SE, CCT, MLT, RBT, PAD and PSBT for increased PCE were -8.00 to -8.31 D, 481.0-498.5 μm, 139.5-144.5 μm, 255.5-263.5 μm, 26.9-28.3% and 48.9-52.6%, respectively. Eyes with thinner corneas, higher myopia requiring greater MLT and lower RBT exhibited greater predispositions towards posterior protrusion. The thresholds for preventing forward posterior corneal displacement were 26.9-28.3% for PAD and 48.9-52.6% for PSBT. Prediction of posterior corneal stability is useful for assessing surgical risks post-SMILE.