Prevention of Argentinian flag sign in intumescent cataracts using anterior chamber air bubble and cortical fluid release techniques.

BACKGROUND: To investigate the efficiency of a new method for the prevention of argentinian flag sign during the process of continuous, circular, and centered anterior capsulotomy (CCC) on the anterior capsule in cortically liquefied intumescent cataracts. This study was registered in an appropriate registry and the registration number of registration was xyy11[2022]-XJSFX-087; The date of of registration was 2022-04-29. METHODS: Preoperative examinations including slit-lamp examination, ocular A-scan ultrasonography, and Ultrasound Biomicroscopy (UBM) UBM were conducted on 61 patients with intumescent cataracts. Cases with cortically liquefied intumescent cataracts were selected and after staining with indocyanine green, the anterior chamber air bubble technique was used to compress the anterior capsule, and liquefied cortex was aspirated using a puncture needle. Corrected Distance Visual Acuity (CDVA) and intraocular pressure were recorded on postoperative days 1, 1 week, 1 month, and 6 months. Intraoperative and postoperative complications were documented and analyzed. RESULTS: Fifty eyes were identified as having cortically liquefied intumescent cataracts. No cases of the Argentinian flag sign occurred, and standard capsulorrhexis was achieved, facilitating smooth phacoemulsification. All patients achieved satisfactory outcomes at follow-ups of 1 day, 1 week, 1 month, and 6 months postoperatively. Mild corneal edema was observed in three cases on the first postoperative day, with no other complications noted. CONCLUSIONS: The anterior chamber air bubble technique combined with cortical fluid release technique can prevent the occurrence of the Argentinian flag sign in cortically liquefied intumescent cataracts, this method is simple, convenient and economic for the clinical promotion.

Comparison of the IOL Master and Pentacam in the measurement of anterior segment parameters in patients with high myopia and cataracts.

PURPOSE: This study aimed to compare the differences between the Zeiss IOL Master and Oculus Pentacam in keratometry and central anterior chamber depth (ACD) measurements in patients with high myopia and cataracts. METHODS: Between January 2019 and December 2020, 89 patients (103 eyes) with cataracts and high myopia who underwent preoperative cataract evaluation at Nanchang First Hospital were selected for retrospective analysis. Keratometry (K1, K2) and ACD were measured with the IOL Master and Pentacam. Paired t-tests were performed to compare the differences, while the Bland-Altman method was used to evaluate the agreement. RESULTS: The K1 value was (43.15±2.44) D for the IOL Master and (42.98±2.47) D for the Pentacam, and the difference between the two instruments was statistically significant (P<0.01). The K2 value was (44.55±2.63) D for the IOL Master and (44.32±2.55) D for the Pentacam. The ACD was (3.44±0.33)mm for the IOL Master and (3.39±0.36)mm for the Pentacam. There were statistically significant differences between the two instruments in both keratometry and ACD (P<0.01). The absolute values of the maximum difference between the two instruments for K1 and K2 were 1.1 and 1.07; thus, the consistency of the two instruments with respect to this measurement was poor. However, the absolute value of the maximum difference between the two instruments for ACD was 0.34, so the consistency of the two instruments in relation to this measurement was good. CONCLUSIONS: Both the IOL Master and the Pentacam can be used in the measurement of keratometry and ACD in patients with high myopia and cataracts, but the keratometry measurements should be compared in clinical application.

Comparison of measurements and calculated lens power using three biometers: a Scheimpflug tomographer with partial coherence interferometry and two swept source optical coherence tomographers.

PURPOSE: To compare the biometric measurements obtained from the Pentacam AXL Wave, IOLMaster 700, and ANTERION and calculate the recommended intraocular lens power using the Barrett Formulae. METHODS: This was a retrospective cross-sectional study of patients who underwent biometry using the Pentacam AXL Wave, IOLMaster 700, and ANTERION. Flat keratometry (K1), steep keratometry (K2), anterior chamber depth (ACD), and axial length (AL) from each device were measured and compared. These parameters were used to calculate the recommended IOL powers using the Barrett formula. RESULTS: The study included 252 eyes of 153 patients. The IOLMaster had the highest acquisition rate among the two biometers. The Pentacam obtained the shortest mean AL, the IOLMaster measured the highest mean keratometry values, and the ANTERION measured the highest mean ACD. In terms of pairwise comparisons, keratometry and axial length were not significantly different between the Pentacam-IOLMaster and ANTERION-IOLMaster groups, while the rest of the pairwise comparisons were statistically significant. In nontoric and toric eyes, 35-45% of patients recommended the same sphere of IOL power. In another 30-40%, the Pentacam and ANTERION recommended an IOL power one step greater than that of the IOLMaster-derived data. 50% of the study population recommended the same toric-cylinder IOL power. CONCLUSIONS: The Pentacam AXL Wave, IOLMaster 700, and ANTERION can reliably provide data for IOL power calculations; however, these data are not interchangeable. In nontoric and toric eyes, 35-45% of cases recommended the same sphere IOL power, and in another 30-40%, the Pentacam and ANTERION recommended one-step higher IOL power than the IOLMaster-derived data. In targeting emmetropia, selecting the first plus IOL power is advisable when using the Pentacam and ANTERION to approximate the IOL power calculations recommended by the IOLMaster 700.

Anatomical and Micro-CT measurement analysis of ocular volume and intraocular volume in adult Bama Miniature pigs, New Zealand rabbits, and Sprague-Dawley rats.

AIM: Utilizing a combination of micro-computed tomography (micro-CT) and anatomical techniques for the volumetric assessment of the eyeball and its constituents in Bama Miniature Pigs, New Zealand rabbits, and Sprague-Dawley(SD) rats. METHOD: Six Bama Miniature pigs, New Zealand rabbits, and SD rats were enrolled in the study. Micro-CT and gross volumetric estimation of ocular volume were employed to acquire data on ocular volume, anterior chamber volume, lens volume, and vitreous cavity volume for each eye. RESULTS: The eyeball volume of pigs ranges from approximately 5.36 ± 0.27 to 5.55 ± 0.28 ml, the lens volume from approximately 0.33 ± 0.02 to 0.37 ± 0.06 ml, the anterior chamber volume from approximately 0.19 ± 0.05 to 0.28 ± 0.04 ml, and the vitreous volume is approximately 3.20 ± 0.18 ml. For rabbits, the eye volume, lens volume, anterior chamber volume, and vitreous volume range from approximately 3.02 ± 0.24 to 3.04 ± 0.24 ml, 0.41 ± 0.02 to 0.44 ± 0.02 ml, 0.23 ± 0.04 to 0.26 ± 0.05 ml, and 1.54 ± 0.14 ml, respectively. In SD rats, the volumes are 0.14 ± 0.02 to 0.15 ± 0.01 ml for the eyeball, 0.03 ± 0.00 to 0.03 ± 0.00 ml for the lens, 0.01 ± 0.00 to 0.01 ± 0.01 ml for the anterior chamber, and 0.04 ± 0.01 ml for the vitreous volume. CONCLUSION: The integration of micro-CT and gross volumetric estimation of ocular volume proves effective in determining the eyeball volume in Bama Miniature Pigs, New Zealand rabbits, and SD rats. Understanding the volume distinctions within the eyeballs and their components among these experimental animals can lay the groundwork for ophthalmology-related drug research.

Evaluation of repeatability and agreement of two optical biometers for intraocular lens power calculation.

The repeatability of two biometers (Lenstar-LS900 and Eyestar-900) to measure ocular parameters and intraocular lens (IOL) power calculation, and their agreement were evaluated. 134 eyes of 134 participants were measured thrice with each biometer. Axial length (AL), anterior chamber depth (ACD), lens thickness (LT) and keratometry (K) were evaluated. The IOL power was calculated using different formulas. The repeatability limit (RLimit), the mean differences (MD) and the limits of agreement (LoA) were calculated. The RLimits for all parameters were higher with Lenstar compared to Eyestar. RLimits were lower than 0.50 D except for Barrett Universal II (0.54 D) and Haigis (0.51 D) formulas with the Lenstar. Mean differences were lower than 0.01 mm for AL, ACD and LT, and lower than 0.03 D for K. MD ranged from 0 to 0.02 D for all formulas except for Barrett and Hill. When dividing the sample into subgroups (short, normal and long eyes), the MDs were similar for the IOL power and were lower than 0.03 D, except for the Barrett and Hill formulas. Both biometers provide repeatable biometry and IOL power calculations. The LoA interval for the IOL power calculation was between 0.75 and 1.50D, which was similar among the subgroups.

Anterior Chamber Flare as a Non-Invasive Assessment of Intraocular Immune Status and Ocular Complications in Proliferative Diabetic Retinopathy.

Proliferative diabetic retinopathy (PDR) is a vision-threatening complication of diabetes mellitus (DM). Anterior chamber (AC) flare and intraocular cytokines are potent biomarkers reflecting the intraocular immune status in PDR. This study aimed to elucidate the complex interrelationship between AC flare and intraocular cytokines in PDR eyes. A retrospective observational study was conducted on 19 PDR eyes of 19 patients with type 2 DM, and on 19 eyes of 19 patients with idiopathic macular hole or epiretinal membrane as controls. AC flare was measured before pars plana vitrectomy (PPV). Aqueous humor (AH) and vitreous fluid (VF) samples were collected at the time of PPV, and the quantities of 27 cytokines in both intraocular fluids were analyzed. In the PDR and control groups, Spearman's rank correlation analysis revealed a positive correlation between AC flare and IL-8 level in both AH and VF. Additionally, IL-8 levels in AH correlated positively with IL-8 levels in VF. In the PDR group, receiver operating characteristic curve analysis identified IL-8 level in AH as a significant predictor for both diabetic macular edema (DME) and vitreous hemorrhage (VH) complications. The cut-off values of IL-8 were established at ≥26.6 pg/mL for DME and ≥7.96 pg/mL for VH. Given the positive correlation between AC flare and AH IL-8 level, the present findings suggest that AC flare value may potentially be a non-invasive biomarker for predicting DME.

Lens Power and Associated Factors in Nonhuman Primate Subjects: A Cross-sectional Study.

Purpose: We aimed to examine the normative profile of crystalline lens power (LP) and its associations with ocular biometric parameters including age, axial length (AL), spherical equivalent refraction (SE), corneal radius (CR), lens thickness, anterior chamber depth, and AL/CR ratio among a cynomolgus monkey colony. Methods: This population-based cross-sectional Non-human Primate Eye Study recruited middle-aged subjects in South China. All included macaques underwent a detailed ophthalmic examination. LP was calculated using the modified Bennett's formula, with biometry data from an autorefractometer and A-scan. SPSS version 25.0 was used for statistical analysis. Results: A total of 301 macaques with an average age of 18.75 ± 2.95 years were collected in this study. The mean LP was 25.40 ± 2.96 D. Greater LP was independently associated with younger age, longer AL, and lower SE (P = 0.028, P = 0.025, and P = 0.034, respectively). LP showed a positive correlation with age, SE, CR, AL, lens thickness, and anterior chamber depth, whereas no correlation was observed between LP and AL/CR ratio. Conclusions: Our results suggested the LP distribution in the nonhuman primate colony and indicated that AL and SE strongly influenced the rate of LP. Therefore, this study contributed to a deeper understanding of the relative significance of the LP on the optics of the crystalline lens study.

Iris Morphological and Biomechanical Factors Influencing Angle Closure During Pupil Dilation.

Purpose: To use finite element (FE) analysis to assess what morphologic and biomechanical factors of the iris and anterior chamber are more likely to influence angle narrowing during pupil dilation. Methods: The study consisted of 1344 FE models comprising the cornea, sclera, lens, and iris to simulate pupil dilation. For each model, we varied the following parameters: anterior chamber depth (ACD = 2-4 mm) and anterior chamber width (ACW = 10-12 mm), iris convexity (IC = 0-0.3 mm), iris thickness (IT = 0.3-0.5 mm), stiffness (E = 4-24 kPa), and Poisson's ratio (v = 0-0.3). We evaluated the change in (△∠) and the final dilated angles (∠f) from baseline to dilation for each parameter. Results: The final dilated angles decreased with a smaller ACD (∠f = 53.4° ± 12.3° to 21.3° ± 14.9°), smaller ACW (∠f = 48.2° ± 13.5° to 26.2° ± 18.2°), larger IT (∠f = 52.6° ± 12.3° to 24.4° ± 15.1°), larger IC (∠f = 45.0° ± 19.2° to 33.9° ± 16.5°), larger E (∠f = 40.3° ± 17.3° to 37.4° ± 19.2°), and larger v (∠f = 42.7° ± 17.7° to 34.2° ± 18.1°). The change in angles increased with larger ACD (△∠ = 9.37° ± 11.1° to 15.4° ± 9.3°), smaller ACW (△∠ = 7.4° ± 6.8° to 16.4° ± 11.5°), larger IT (△∠ = 5.3° ± 7.1° to 19.3° ± 10.2°), smaller IC (△∠ = 5.4° ± 8.2° to 19.5° ± 10.2°), larger E (△∠ = 10.9° ± 12.2° to 13.1° ± 8.8°), and larger v (△∠ = 8.1° ± 9.4° to 16.6° ± 10.4°). Conclusions: The morphology of the iris (IT and IC) and its innate biomechanical behavior (E and v) were crucial in influencing the way the iris deformed during dilation, and angle closure was further exacerbated by decreased anterior chamber biometry (ACD and ACW).

Double-Cannula Maneuver for the Double-Roll Configuration of Donor Descemet Membrane Outside Recipient Anterior Chamber During Descemet Membrane Endothelial Keratoplasty.

PURPOSE: The purpose of this study was to present a new surgical technique to convert a single roll of Descemet membrane (DM) into a double roll using 2 cannulas in a balanced salt solution-filled Petri dish during DM endothelial keratoplasty. METHODS: A single DM roll stained with trypan blue was placed in a balanced salt solution-filled Petri dish. Two cannulas (28G) were introduced from opposite ends of the single roll, inserted into the roll, and slowly spread apart to change the single roll into a double roll. The DM was aspirated into the modified Jones tube and loaded, maintaining a double-roll configuration with endothelium-down orientation in a bevel-up position. The modified Jones tube with the bevel down was inserted into the recipient anterior chamber through the main wound. The modified Jones tube was rotated to the bevel-up orientation. After checking the graft orientation, the DM was inserted into the recipient anterior chamber. The double-roll DM was easily unfolded by tapping the center of the cornea using a cannula. A 28G cannula was inserted under the DM, and the anterior chamber was filled with air. RESULTS: Three months after surgery, the patient's corrected visual acuity in the right eye was 6/7.5 and the endothelial cell count was 1095/mm 2 . The corneal thickness was 533 µm, and the cornea was clear. CONCLUSIONS: The double-cannula maneuver mechanically changes the single roll of the donor DM to a double roll outside the recipient anterior chamber, making DM unfolding easier and minimizing the risk of upside-down apposition of the donor DM.

Development and validation of a novel vault prediction formula based on structural parameters of the anterior and posterior chambers.

BACKGROUND: Accurate prediction of postoperative vault in implantable collamer lens (ICL) implantation is crucial; however, current formulas often fail to account for individual anatomical variations, leading to suboptimal visual outcomes and necessitating improved predictive models. We aimed to verify the prediction accuracy of our new predictive model for vaulting based on anterior and posterior chamber structural parameters. METHODS: This retrospective observational study included 137 patients (240 eyes) who previously underwent ICL surgery. Patients were randomly divided into the model establishment (192 eyes) or validation (48 eyes) groups. Preoperative measurements of the anterior and posterior chamber structures were obtained using Pentacam, CASIA2 anterior segment optical coherence tomography (AS-OCT), ultrasound biomicroscopy, and other devices. Stepwise multiple linear regression analysis was used to evaluate the relationship between the vault and each variable (WL formula). The Friedman test was performed for the vaulting prediction results of the WL, NK (Ver. 3), and KS formulas (Ver. 4) in CASIA2 AS-OCT, as well as the Zhu formula and vault measurements. The proportions of prediction error within ± 250 µm per formula were compared. RESULTS: The predicted vault values of the WL, NK, KS, and Zhu formulas and vault measurements were 668.74 ± 162.12, 650.85 ± 248.47, 546.56 ± 128.99, 486.56 ± 210.76, and 716.06 ± 233.84 µm, respectively, with a significant difference (χ2 = 69.883, P = 0.000). Significant differences were also found between the measured vault value and Zhu formula, measured vault value and KS formula, WL formula and Zhu formula, WL formula and KS formula, NK formula and KS formula, and NK formula and Zhu formula (P < 0.001) but not between other groups. The proportions of prediction error within ± 250 µm per formula were as follows: WL formula (81.3%) > NK formula (70.8%) > KS formula (66.7%) > Zhu formula (54.2%). CONCLUSIONS: The WL formula, which considers the complexity of the anterior and posterior chamber structures, demonstrates greater calculation accuracy, compared with the KS (Ver. 4) and Zhu formulas. The proportion of absolute prediction error ≤ 250 µm is higher with the WL formula than with the NK formula (ver. 3). This enhanced predictive capability can improve ICL sizing decisions, thereby increasing the safety and efficacy of ICL implantation surgeries.

Accuracy of intraocular lens calculation formulas based on swept-source OCT biometer in cataract patients with phakic intraocular lens.

PURPOSE: To research the accuracy of intraocular lens (IOL) calculation formulas and investigate the effect of anterior chamber depth (ACD) and lens thickness (LT) measured by swept-source optical coherence tomography biometer (IOLMaster 700) in patients with posterior chamber phakic IOL (PC-pIOL). METHODS: Retrospective case series. The IOLMaster 700 biometer was used to measure axial length (AL) and anterior segment parameters. The traditional formulas (SRK/T, Holladay 1 and Haigis) with or without Wang-Koch (WK) AL adjustment, and new-generation formulas (Barret Universal II [BUII], Emmetropia Verifying Optical [EVO] v2.0, Kane, Pearl-DGS) were utilized in IOL power calculation. RESULTS: This study enrolled 24 eyes of 24 patients undergoing combined PC-pIOL removal and cataract surgery at Xiamen Eye Center of Xiamen University, Xiamen, Fujian, China. The median absolute prediction error in ascending order was EVO 2.0 (0.33), Kane (0.35), SRK/T-WKmodified (0.42), Holladay 1-WKmodified (0.44), Haigis-WKC1 (0.46), Pearl-DGS (0.47), BUII (0.58), Haigis (0.75), SRK/T (0.79), and Holladay 1 (1.32). The root-mean-square absolute error in ascending order was Haigis-WKC1 (0.591), Holladay 1-WKmodified (0.622), SRK/T-WKmodified (0.623), EVO (0.673), Kane (0.678), Pearl-DGS (0.753), BUII (0.863), Haigis (1.061), SRK/T (1.188), and Holladay 1 (1.513). A detailed analysis of ACD and LT measurement error revealed negligible impact on refractive outcomes in BUII and EVO 2.0 when these parameters were incorporated or omitted in the formula calculation. CONCLUSION: The Kane, EVO 2.0, and traditional formulas with WK AL adjustment displayed high prediction accuracy. Furthermore, the ACD and LT measurement error does not exert a significant influence on the accuracy of IOL power calculation formulas in highly myopic eyes implanted with PC-pIOL.

Impact and Correction of an Anterior Phakic Intraocular Lens on Swept-Source Optical Coherence Tomography Biometry.

PURPOSE: To evaluate the impact of anterior chamber phakic intraocular lens (pIOL) on swept-source optical coherence tomography (SS-OCT) biometric measurements and IOL power calculation. METHODS: This retrospective analysis of 67 eyes of 49 patients with previous anterior chamber pIOL implantation analyzed the accuracy of automatic segmentation of the anterior surface of the crystalline lens and its impact on anterior chamber depth (ACD, measured from epithelium to lens), lens thickness measurements, and IOL power calculation. The sample was divided into two groups: correct detection of the anterior surface of the crystalline lens and inaccurate detection. Segmentation of eyes from the inaccurate detection group was manually corrected and ACD and lens thickness were calculated using ImageJ software. IOL power was calculated using 7 formulas for both measurements. RESULTS: The anterior surface of the crystalline lens was mis-identified in 13 (19.4%) eyes. ACD was underestimated (Δ -0.85 ± 0.33 mm, P < .001) and lens thickness was overestimated (Δ +0.81 ± 0.25 mm, P < .001). Manual correction changed the target spherical equivalent only in the Haigis formula (P = .009). After correction for segmentation bias, the Pearl DGS, Cooke K6, and EVO 2.0 formulas showed the lowest prediction error, with the Pearl DGS showing greatest accuracy within ±1.00 diopters of prediction error range (81.0%). CONCLUSIONS: SS-OCT biometry misidentifies the anterior surface of the crystalline lens in a significant proportion, resulting in significant IOL power calculation error in the Haigis formula. Manual proofing of segmentation is mandatory in every patient with anterior chamber pIOL implantation. After correct segmentation, the Pearl DGS, Cooke K6, and EVO seem to be the best formulas. [J Refract Surg. 2024;40(8):e562-e568.].

Anterior Chamber Intraocular Lens Implantation Versus Four-Flanged Scleral Fixation Technique for Patients With Loss of Capsular Support During Routine Cataract Surgery.

PURPOSE: To compare the outcomes of anterior chamber intraocular lens (AC-IOL) implantation versus the four-flanged scleral fixation technique in eyes with loss of capsular support during routine cataract surgery. METHODS: This was a retrospective cohort study of all patients in whom an IOL was implanted either during or after short-term aphakia due to loss of capsular and sulcus support in a routine cataract surgery with at least 6 months of follow-up time between 2015 and 2023 in a tertiary medical center in Israel. Two different IOL implantation techniques were compared: the implantation of an angle-supported ACIOL and four-flanged scleral fixation. Main outcome measures included postoperative complications such as pseudophakic bullous keratopathy, loss of intraocular pressure control and glaucoma, IOL subluxation, and retinal detachment. RESULTS: Sixty-five eyes of 65 patients were included in the study, 33 eyes in the AC-IOL group and 32 eyes in the flange group. Follow-up time was 29.92 ± 20.02 months in the AC-IOL group and 20.17 ± 15.56 months in the flange group (P = .087). Pseudophakic bullous keratopathy was observed in 10 (30.3%) patients in the AC-IOL group and in 1 (3.1%) patient in the flange group (P = .04). This association remained significant using survival analysis (P = .006). In 4 (12.1%) patients in the AC-IOL group, a glaucoma filtering procedure was performed to control the intraocular pressure compared with none in the flange group (P = .042). CONCLUSIONS: In the setting of loss of capsular support during routine cataract surgery, four-flanged scleral fixation showed an overall lower rate of complications and significantly reduced rate of subsequent surgical interventions. [J Refract Surg. 2024;40(8):e520-e526.].

Effect of Tiotropium on eye findings in the treatment of chronic obstructive pulmonary disease.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a persistent, chronic inflammatory disease of the lungs. Tiotropium, used in the treatment of COPD, is a muscarinic receptor antagonist that provides long-acting bronchodilation. Our study aimed to investigate the effects of Tiotropium on anterior chamber parameters. METHODS: The study was conducted as an observational cross-sectional and prospectively between October 2023 and April 2024. Patients were examined in three groups: Group 1 consisted of untreated COPD patients; Group 2 consisted of healthy volunteers similar age and gender, and Group 3 included COPD patients receiving Tiotropium 18 mcg via HandiHaler. Anterior chamber parameters, intraocular pressure values, and photopic-mesopic pupil diameters were measured at the initial visit for Group 1 and Group 2 patients, and at the third month of treatment for Group 3 patients. RESULTS: Thirty-six patients were included in each group in the study. No significant differences were observed in ocular findings between the patient and control groups. In COPD patients receiving Tiotropium, narrowing of angle parameters, an increase in photopic-mesopic pupil diameters, and intraocular pressure were observed at the third month of treatment. CONCLUSION: This study is the first research that investigate the effects of Tiotropium on anterior chamber parameters, pupil diameters, and intraocular pressure in COPD treatment. In conclusion, patients with COPD receiving Tiotropium therapy for three months showed narrowing in angle parameters, an increase in intraocular pressure, and photopic-mesopic pupil diameter; however, no patients developed drug-induced acute angle closure glaucoma. TRIAL REGISTRATION: An independent ethics committee approved the study (Giresun EAH KEAK 2023/180 and 9.10.2023/02) which was performed in accordance with the Declaration of Helsinki, Guidelines for Good Clinical Practice. The study was conducted as prospectively, observational case-control. The Clinical Trial Number obtained for the study is NCT06525051 and was taken on 2024-07-29.

Glaucoma-Protective Human Single-Nucleotide Polymorphism in the Angpt2 Locus Increased ANGPT2 Expression and Schlemm Canal Area in Mice-Brief Report.

BACKGROUND: The ANGPT (angiopoietin)-TEK (tyrosine kinase, endothelial) vascular signaling pathway plays a key role in the formation of Schlemm canal, and loss-of-function mutations in the TEK or ANGPT1 gene are associated with primary congenital glaucoma in children. In genome-wide association studies, an association was identified between protection from primary open-angle glaucoma and the single-nucleotide polymorphism rs76020419 (G>T), located within a predicted miR-145-binding site in the 3' untranslated region of ANGPT2. To date, the functional impact of this variant in the anterior chamber of the eye remains largely unexplored. METHODS: MT (mutant) mice harboring an orthologous rs76020419 minor allele (T) were generated using CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeat-associated 9). Plasma and tissue samples, including eyes, were collected, and ANGPT2 expression was quantified using ELISA. Anterior segments from eyes were collected from WT (wild-type) and MT mice, and Schlemm canal area was quantified. RESULTS: In the MT group, higher ANGPT2 concentrations were observed in the plasma, lungs, kidneys, and eyes (P=0.0212, P<0.001, P=0.0815, and P=0.0215, respectively). Additionally, the Schlemm canal was larger in MT mice compared with WT mice (P=0.0430). CONCLUSIONS: The rs76020419 minor allele (T) is associated with increased levels of ANGPT2 and a larger Schlemm canal in mice. These findings suggest a potential protective mechanism in glaucoma.

Parallel comparison of ocular metrics in non-human primates with high myopia by LS900, ultrasonography and MRI-based 3D reconstruction.

We investigate the ocular dimensions and shape by using Lenstar900 (LS900), A-scan ultrasonography, and Magnetic Resonance Imaging (MRI) in highly myopic Macaca fascicularis. The ocular dimensions data of LS900, A-scan ultrasonography and MRI was assessed from 8 eyes (4 adult male cynomolgus macaque) with extremely high myopia (≤-1000DS) and compared by means of coefficients of concordance and 95% limits of agreement. Multiple regression analysis was performed to explore the associations between ocular biometry, volume, refraction and inter-instrument discrepancies. Test-retest reliability of three measurements of ocular parameters at two time points was almost equal (intraclass correlation = 0.831 to 1.000). The parallel-forms reliability of three measurements was strong for vitreous chamber depth (VCD) (coefficient of concordance = 0.919 to 0.981), moderate for axial length (AL) (coefficient of concordance = 0.486 to 0.981), and weak for anterior chamber depth (ACD) (coefficient of concordance = 0.267 to 0.621) and lens thickness (LT) (coefficient of concordance = 0.035 to 0.631). The LS900 and MRI systematically underestimated the ACD and LT comparing to A-scan ultrasonography (P < 0.05). Notably, the average AL on LS900 displayed a significant correlation with those on MRI (r = 0.978, P < 0.001) and A-scan ultrasonography (r = 0.990, P < 0.001). Almost 4/5 eyeballs were prolate. The mean eyeball volume positively correlated with AL (r = 0.782, P = 0.022), the width (r = 0.945, P = 0.000), and the length (r = 0.782, P = 0.022) of eyeball, while negatively correlated with SER (r = -0.901, P = 0.000). In conclusion, there was a high inter-instrument concordance for VCD with LS900, A-scan ultrasonography and MRI, while ACD and LT were underestimated with LS900 compared to A-scan ultrasonography, and the LS900 and A-scan ultrasonography could reliably measure the AL. MRI further revealed an equatorial globe shape in extremely myopic non-human primates.

Influence of Ocular Biometric Parameters on Intraocular Lens Position: A Prospective Cohort Study.

PURPOSE: To assess the influence of ocular biometric parameters on intraocular lens (IOL) tilt and decentration after cataract surgery. METHODS: Patients scheduled for cataract surgery were screened for inclusion in this prospective cohort study. Tilt and decentration of the crystalline lens and IOL were measured using the CASIA2 (Tomey). Anterior chamber depth (ACD), lens thickness (LT), and axial length (AL) were preoperatively measured by the IOLMaster 700 (Carl Zeiss Meditec AG). Multivariate regression analysis was performed to assess the influence of ocular biometric parameters on IOL tilt and decentration after cataract surgery. RESULTS: In total, 191 eyes of 120 patients were included. Age was positively correlated with IOL tilt, whereas ACD and AL were negatively correlated with IOL tilt. A strong positive correlation was found between preoperative crystalline lenses and postoperative IOLs in tilt magnitude (r = 0.769, P < .001) and tilt direction (r = 0.688, P < .001). A positive correlation was found between preoperative and postoperative lens decentration magnitude and decentration direction. Greater postoperative IOL tilt and decentration were significantly associated with greater preoperative crystalline lens tilt (P < .001) and decentration (P = .027). CONCLUSIONS: IOL tilt was greater in older patients. Shorter AL and shallower ACD contributed to greater IOL tilt. The tilt and decentration of the IOL will be greater in patients with greater tilt and decentration of the crystalline lens. [J Refract Surg. 2024;40(7):e438-e444.].