Translational Vision Science & Technology最新文献

Purpose: To assess the safety of acoustic radiation force optical coherence elastography in the crystalline lens in situ.

Methods: Acoustic radiation force (ARF) produced by an immersion single-element ultrasound transducer (nominal frequency = 3.5 MHz) was characterized using a needle hydrophone and used for optical coherence elastography (OCE) of the crystalline lens. Preamplified signals at 50, 100, 250, 500, 750, 1000, and 1250 mV peak amplitude were tested on ex vivo porcine eyes (n = 21). Three-dimensional optical coherence tomography (OCT) and confocal microscopy images were acquired before and after ARF exposure to each signal amplitude to determine damage.

Results: The acoustic intensity of the ultrasound transducer at 100-mV preamplified peak amplitude input demonstrated a signal-to-noise ratio high enough for tracking elastic wave propagation in the lens and spatial-peak pulse-average (SPPA) intensity of 24.1 W/cm² and mechanical index (MI) of 0.46. The SPPA intensity was lower than the U.S. Food and Drug Administration (FDA) safety limit (28 W/cm2), but the MI was twice the safety limit (0.23). OCT structural and confocal microscopy images showed damage only at levels exceeding 1150 W/cm2 and 3.2 for SPPA intensity and MI, respectively.

Conclusions: OCT and confocal microscopy showed that, even when the intensity exceeded FDA recommendations (>100 mV), no noticeable damage was observed. Although a further reduction in acoustic intensity is necessary to meet FDA safety limits, ARF-based elastography shows promise for safe clinical translation in quantitatively characterizing lenticular biomechanical properties.

Translational relevance: This work assessed the safety standards for acoustic radiation force to be used in human lens elastography according to the FDA safety limits.

Purpose: Currently, no standard for the measurement of retinal oxygen extraction exists. Here, we present a novel approach for measurement of retinal oxygen extraction based on two commercially available devices, namely laser speckle flowgraphy (LSFG) and retinal oximetry.

Methods: The study was conducted in a randomized, double-masked design. Two study days were scheduled for each healthy participant. On one study day, measurements were performed during breathing of 100% oxygen to induce hyperoxia and on the other study day during breathing of 12% oxygen in nitrogen to induce hypoxia. To obtain data for short- and long-term reproducibility, baseline measurements during breathing of room air were performed twice on both study days. Retinal oxygen extraction was calculated from retinal oxygen saturation measurements using the oxygen module of the dynamic vessel analyzer (Imedos, Jena, Germany) and retinal blood flow measurements using LSFG (Nidek, Tokyo, Japan).

Results: As expected, breathing of 100% oxygen induced a significant decrease in retinal oxygen extraction of 36% ± 17% (P < 0.001). During hypoxia, retinal oxygen extraction did not change from baseline (P = 0.153). For short-term reproducibility, the intraclass correlation coefficient was excellent (0.910) and good (0.879) for long-term reproducibility. Coefficient of variation between measurements was 9.8% ± 7.0% for short-term and 10.4% ± 8.8% for long-term reproducibility.

Conclusions: The data obtained in the present experiments show that the new approach to measure retinal oxygen extraction is valid and reproducible in healthy volunteers.

Translational relevance: The technique may become a valuable tool in studying retinal hypoxia in a wide variety of ocular and systemic diseases in the future.

Purpose: Sozinibercept inhibits vascular endothelial growth factors (VEGFs) C and D. This study evaluated outcomes following switching from anti-VEGF-A monotherapy to intravitreal injections of three dose levels of sozinibercept in combination with aflibercept in patients with diabetic macular edema (DME).

Methods: A phase 1b, open-label, multicenter dose-escalation study with a 24-week follow-up. Patients received 3 loading doses of aflibercept (2 mg) in combination with sozinibercept (0.3, 1, or 2 mg) once every 4 weeks and were followed through week 24. The primary endpoint was safety, and secondary endpoints included mean change from baseline in best-corrected visual acuity (BCVA) and anatomic changes on imaging.

Results: Nine patients received sozinibercept in combination with aflibercept after a mean (SD) of 6.3 (2.4) injections of previous anti-VEGF-A. Sozinibercept combination therapy was well tolerated with no dose-limiting toxicities. Mean change in BCVA at week 12 was +7.7 letters (95% confidence interval [CI], 2-13.3) from baseline (65 letters [SD 5.5]) with a dose response for increasing doses of sozinibercept. At week 12, central subfield thickness (CST) was decreased by -71 µm (95% CI, -117 to -26) from baseline (434 µm [SD 58]), and 6 of 9 (67%) patients had a ≥50% reduction in excess foveal thickness.

Conclusions: In prior-treated patients with center-involved DME, switching to sozinibercept in combination with aflibercept was well tolerated with improved visual and anatomic outcomes.

Translational relevance: This first-in-human study builds upon basic research by providing safety and preliminary efficacy of sozinibercept (anti-VEGF-C/-D) in combination with aflibercept for DME.

Purpose: To demonstrate that high-seed, ultra-high-resolution spectral-domain optical coherence tomography (SD-OCT) technology can image in vivo fine morphological features in the healthy and pathological human limbus.

Methods: A compact, fiberoptic SD-OCT system was developed for imaging the human limbus. It combines ∼1.5-µm isotropic spatial resolution in ocular tissue and an acquisition rate of 250,000 A-scans per second. The imaging probe was outfitted with two microscope objectives to provide flexibility in the choice of wide field of view and extended depth of focus versus high lateral resolution. The clinical potential of the system was evaluated by imaging subjects with limbal stem cell dysfunction (LSCD; n = 4) and healthy controls (n = 6).

Results: Limbus images acquired from the healthy controls showed normal cellular structure of the limbal crypts, palisades of Vogt (POVs), and vasculature of the underlying scleral tissue. Images acquired from the LSCD subjects showed distortions or absence of POVs, invasion of highly scattering conjunctival tissue over the limbal and peripheral corneal epithelium, scarring and thinning of the limbal epithelium, and neovascularization.

Conclusions: The combination of high OCT spatial resolution and rapid image acquisition rate allows for in vivo, contactless, volumetric visualization of fine morphological details that could be beneficial for the precise diagnosis and grading of LSCD, planning of treatment, and evaluation of the effectiveness of the treatment approaches.

Translational relevance: The OCT technology described here could improve the clinical diagnostics and grading of LSCD, preoperative planning, and postoperative evaluation of LSCD subjects, in addition to monitoring the effectiveness of various LSCD treatments.

Purpose: To derive estimates of clinically meaningful change (improvement) on the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25) in patients with diabetic macular edema (DME) using anchor- and distribution-based methods.

Methods: In this exploratory post hoc analysis of data from the RIDE/RISE (NCT00473382/NCT00473330) clinical trials of ranibizumab for DME, the NEI VFQ-25 was completed at baseline and six, 12, 18, and 24 months. Anchor-based (≥5-, ≥10-, and ≥15-letter gain in best-corrected visual acuity [BCVA]) and distribution-based estimates were calculated. Subgroup analyses included outcomes when the study eye was the better- or worse-seeing eye.

Results: Baseline characteristics were balanced between the trials (RIDE, N = 382; RISE, N = 377). Anchor-based estimates of clinically meaningful improvement in composite scores (for ≥15-letter gain in BCVA) were 3.78 and 2.23 for RIDE and RISE, respectively. Estimates appeared similar for most subscales: near activities (4.11 and 3.31), distance activities (3.53 and 3.74), driving difficulties (5.15 and 3.15), and vision-specific dependency (4.70 and 1.83). Supportive distribution-based meaningful change composite score estimates also were similar between RIDE and RISE for values based on 0.5 standard deviation (9.85 and 9.70, respectively) or standard error of the mean (5.10 and 4.82, respectively).

Conclusions: These analyses suggest improvement of three to five points on the NEI VFQ-25 composite score and four individual subscales as clinically meaningful in patients with DME.

Translational relevance: This analysis supports considering these thresholds when assessing the clinical risk-benefit of DME treatment from the patient perspective using the NEI VFQ-25.

Purpose: To develop and test a novel optical coherence tomography (OCT) metric for the detection of glaucoma based on a logistic regression model (LRM) and known patterns of glaucomatous damage.

Methods: The six variables of the LRM were based on characteristic patterns of damage seen on the OCT thickness maps of the ganglion cell layer plus inner plexiform layer (GCL+) and retinal nerve fiber layer (RNFL). Two cohorts were used to develop the LRM. The healthy cohort consisted of 400 individuals randomly selected from a real-world reference database (RW-RDB) of OCT widefield scans from 4932 eyes/individuals obtained from 10 optometry practices. The glaucoma cohort consisted of 207 individuals from the same 10 practices but with OCT reports with evidence of optic neuropathy consistent with glaucoma (ON-G). Specificity was assessed with 396 eyes/individuals from a commercial RDB. Sensitivity was assessed with individuals with ON-G from different optometry practices.

Results: For the new LRM metric, the partial area under the reciever operating characteristic curve (AUROC) for specificity >90% was 0.92, and the sensitivity at 95% specificity was 88.8%. These values were significantly greater than those of a previously reported LRM metric (0.82 and 78.1%, respectively) and two common OCT thickness metrics: global circumpapillary RNFL (0.77 and 57.5%, respectively), and global GCL+IPL (0.72 and 47.6%, respectively).

Conclusions: The new metric outperformed other OCT metrics for detecting glaucomatous damage.

Translational relevance: The new metric has the potential to improve the accuracy of referrals from primary care to specialist care via risk scores and calculators, as well as glaucoma definitions for clinical trials. The individual variables of this model may also aid clinical diagnosis.

Purpose: The corneal nerves within the sub-basal nerve plexus (SBNP) display a distinctive whorl-like pattern, a highly dynamic structure that could be a marker of diseases. Previous studies have reported a decrease in whorl nerve density in patients with diabetes, indicating an avenue for noninvasive monitoring of diabetic neuropathy. However, conflicting results have since been reported, highlighting the need for improved quantitative analysis of the corneal whorl. We present an automated algorithm to characterize the whorl shape and test the hypothesis that the whorl organization is affected by diabetic neuropathy.

Methods: The SBNP whorl was analyzed as a vector field, from which seven whorl metrics were calculated. The efficacy of these whorl metrics was demonstrated in synthetic images, ex vivo mouse corneas, and in a publicly available dataset of wide-field in vivo confocal microscopy (IVCM) images of diabetic and control subjects. Linear discriminant analysis and the Peacock test were used to test for statistical differences. Our analysis code is made freely available.

Results: Using our whorl metrics, we were able to quantify different whorl patterns in our patient population and statistically compare cohorts. We determined that whorl patterns tend to present bilaterally in patients (P < 0.001), but there were no significant differences between whorl patterns in patients with diabetes and control subjects, nor between patients with or without neuropathy symptoms.

Conclusions: We present a generalizable framework to statistically compare corneal nerve patterns in cohorts of patients.

Translational relevance: SBNP whorl patterns could serve as a noninvasive marker for ocular diseases, whereas few quantitative IVCM endpoints have been identified to date.

Purpose: Disorders of the anterior optic nerve cause quantifiable patterns, or archetypes (AT), in visual fields (VFs) obtained using standardized automated perimetry using stimulus size III (size III). VFs with stimulus size V (size V) can reduce retest variability in eyes with moderate to severe loss. We postulated that VF testing using both stimuli would show similar ATs in eyes with glaucoma and nonarteritic anterior ischemic optic neuropathy (NAION).

Methods: We used 1969 same-day pairs of 24-2 size III and size V VFs from two datasets. QRK207 is the largest NAION study to date, and the VIPII study measured same-day VFs across many stimulus sizes. We censored raw sensitivities of less than 21 dB for size III and 24 dB for size V and age-standardized to total deviations, before archetypal analysis (AA). We compared the ATs between the two stimuli and the combined data.

Results: Using 14 ATs for both glaucoma and NAION, AA captured similar patterns between the two stimuli in both diseases with 87% of AT pairings having a cosine similarity of 0.8 or greater. The combined ATs retained the patterns in the separate stimuli VFs.

Conclusions: AA shows that size V VFs provide quantifiable patterns of loss similar to size III. This aids in comparing stimulus sizes for monitoring VF patterns in disease progression.

Translational relevance: AA shows similar quantifiable patterns of VF loss with size III or size V, supporting the use of size V to monitor eyes with moderate to severe VF loss.

Purpose: To investigate the toxicity of terpinen-4-ol (T4O) on primary cultured human corneal epithelial cells (HCECs).

Methods: HCECs were exposed to various concentrations (0%-0.1%) of T4O for 15 minutes to 72 hours. Cell viability was assessed using the CCK8 kit and cell counting. Intracellular reactive oxygen species (ROS) were measured after 15 to 60 minutes of T4O exposure. Changes in cell morphology and cytoplasmic actin filaments were observed using phase contrast microscopy and immunocytochemistry. The expression levels of proteins involved in cell survival pathways (mTOR, Akt, Bcl-xL, and BAX) were evaluated by Western blot analysis.

Results: T4O induced dose-dependent toxicity in HCECs. Exposure to 0.05% T4O for 15 minutes significantly decreased cell viability. Lower concentrations (0.025% and 0.0125%) also caused significant toxicity with longer exposure times. Prolonged exposure enhanced cytotoxicity, with 0.05% T4O reducing viability by half after 24 hours and 0.1% T4O causing complete cell death. Increased intracellular ROS and decreased levels of phosphorylated mTOR, phosphorylated Akt, and Bcl-xL, along with increased BAX expression, accompanied this toxicity. F-actin staining revealed significant changes in cell adhesion.

Conclusions: Our study demonstrates that T4O exposure causes significant toxicity in HCECs, depending on concentration and incubation time. This toxic response is associated with increased ROS and decreased cell survival pathway activity.

Translational relevance: The corneal epithelial toxicity data of T4O revealed in this study may be useful in the future use of tea tree oil or the development of tee tree oil-containing eyelid scrub products for treating eyelid demodex infestation.