Spectral-domain Optical Coherence Tomography Research Articles

Retina in Clinical High-Risk and First-Episode Psychosis.

Abnormalities in the retina are observed in psychotic disorders, especially in schizophrenia. Using spectral-domain optical coherence tomography, we investigated structural retinal changes in relatively metabolic risk-free youth with clinical high-risk (CHR, n = 34) and first-episode psychosis (FEP, n = 30) compared with healthy controls (HCs, n = 28). Total retinal macular thickness/volume of the right eye increased in FEP (effect sizes, Cohen's d = 0.69/0.66) and CHR (d = 0.67/0.76) compared with HCs. Total retinal thickness/volume was not significantly different between FEP and CHR. Macular retinal nerve fiber layer (RNFL) thickness/volume of the left eye decreased in FEP compared with HCs (d = -0.75/-0.66). Peripapillary RNFL thickness was not different between groups. The ganglion cell (GCL), inner plexiform (IPL), and inner nuclear (INL) layers thicknesses/volumes of both eyes increased in FEP compared with HCs (d = 0.70-1.03). GCL volumes of both eyes, IPL thickness/volume of the left eye, and INL thickness/volume of both eyes increased in CHR compared with HCs (d = 0.64-1.01). In the macula, while central sector thickness/volume decreased (d = -0.62 to -0.72), superior outer (peri-foveal) sector thickness/volume of both eyes increased (d = 0.81 to 0.86) in FEP compared with HCs. The current findings suggest that distinct regions and layers of the retina may be differentially impacted during the emergence and early phase of psychosis. Consequently, oculomics could play significant roles, not only as a diagnostic tool but also as a mirror reflecting neurobiological changes at axonal and cellular levels.

Evaluating the effects of three anesthetic regimens on retinal structure and function in the living mouse eye using a customized bimodal OCT/ORG system

Abstract Optical coherence tomography (OCT) is a non-invasive imaging technique that generates cross-sectional images of biological tissues at millimeter-level penetration depth with micron-level resolution. In this study, we developed a custom spectral-domain OCT system equipped with a flash stimulus module for dual-modality imaging of mouse retinal structure and function. The axial resolution of the system reached ∼2.7/2 μm in air/tissue following optimization and calibration. We deployed this system to conduct in vivo OCT structural imaging and optoretinography (ORG) functional assessment of mouse retina to investigate the effects of three anesthesia regimens. Statistical analysis of the results indicates that anesthesia results in a smaller relative intensity of inner/outer segment junction and external limiting membrane and a thickening of the outer segment compared to an awake state. Meanwhile, significant differences were observed in the effects on retinal structure and function between isoflurane and tribromoethanol anesthesia, while differences between isoflurane and esketamine+xylazine groups were small. These findings suggest that the type of anesthetic should be taken into account when comparing imaging results across studies reported in the literature.

Punctate hyperreflective vitreous opacities: a ubiquitous finding in healthy children beyond infancy.

The vitreous evolves from birth over lifetime. Little is known about the appearance of the healthy vitreous during childhood. We aimed to characterise posterior vitreous features in healthy children using spectral domain optical coherence tomography (SD-OCT). Retrospective cohort study including healthy eyes of 78 children aged 2-12 years and 39 healthy adults. Patients diagnosed with intraocular inflammation or vitreoretinal pathology were excluded. Proportion of eyes with presence of punctate hyperreflective vitreous opacities (PHVO). Percentage of B-scans demonstrating PHVO within an OCT volume scan, correlation between presence of PHVO and patients' age group, retinal measurements, and presence of premacular bursa were analysed. 154 paediatric eyes (median age 9.08 (IQR 5.17-9.75) years) and 76 adult eyes (30.75 (IQR 26.42-38.08) years) were included; 12244 OCT images were reviewed. All eyes (100%) in the paediatric group and 73% in the adult group presented PHVO. The median percentage of OCT images showing PHVO was 77.05% (IQR 51.23-88.52) in children and 8.0% (IQR 0-16.03) in adults (p < 0.001). Separate analysis of right and left eyes confirmed the results (p < 0001). Premacular bursa appeared in 20.5% of paediatric and 31.6% of adult eyes (p = 0.103). Mean central subfield thickness was significantly lower in children (257 ± 21 µm vs. 276 ± 18 µm, p < 0.001), while median total macular volume was similar (8.59 (IQR 8.25-8.86) mm3 vs. 8.62 (IQR 8.39-8.96) mm3, p = 0.145). This study demonstrates that PHVO are ubiquitous physiologic vitreous findings in healthy children beyond infancy. These findings enhance the understanding of the development of the posterior segment of the eye and might improve paediatric OCT interpretation, potentially avoiding misdiagnoses and unnecessary interventions in children.

Method for Extracting Optical Element Information Using Optical Coherence Tomography

This study examines the measurement of film thickness, curvature, and defects on the surface or inside of an optical element using a highly accurate and efficient method. This is essential to ensure their quality and performance. Existing methods are unable to simultaneously extract the three types of information: thickness, curvature, and defects. Spectral-domain optical coherence tomography (SD-OCT), a non-invasive imaging technique with imaging depths down to the millimeter scale, provides the possibility of detecting the optical element components’ parameters. In this paper, we propose an error correction model for compensating delay differences in A-scan, field curvature, and aberration to improve the accuracy of system fitting measurements using SD-OCT. During data processing, we use the histogram-equalized gray stretching (IAH-GS) method to deal with strong reflections in the thin film layers inside the optics using individual A-scan averages. In addition, we propose a window threshold cutoff algorithm to accurately identify defects and boundaries in OCT images. Finally, the system is capable of rapidly detecting the thickness and curvature of film layers in optical elements with a maximum measurement depth of 4.508 mm, a diameter of 15 × 15 mm, a resolution of 5.69 microns, and a sampling rate of 70 kHz. Measurements were performed on different standard optical elements to verify the accuracy and reliability of the proposed method. To the best of our knowledge, this is the first time that thickness, curvature, and defects of an optical film have been measured simultaneously, with a thickness measurement accuracy of 1.924 µm, and with a difference between the calibrated and nominal curvature measurements consistently within 1%. We believe that this research will greatly advance the use of OCT technology in the testing of optical thin films, thereby improving productivity and product quality.

Optical Coherence Tomography Angiography in Macular Neovascularization Secondary to Focal Choroidal Excavation

Purpose: To highlight the use of multimodal imaging for detecting and monitoring macular neovascularization (MNV) in the presence of focal choroidal excavation. Methods: A case and its findings were analyzed. Results: Spectral-domain optical coherence tomography (OCT) and OCT angiography (OCTA) were performed in a 30-year-old Asian woman with metamorphopsia in the left eye. Imaging showed striking MNV secondary to focal choroidal excavation, and an impressive response to antivascular endothelial growth factor therapy was seen throughout the follow-up. Conclusions: OCTA is a noninvasive, useful imaging modality for diagnosing and monitoring patients with MNV secondary to focal choroidal excavation.

Association between renal function and the Treatment of Diabetic Macular Edema in Long-Term Cohort Study

To determine the correlation between the severity of chronic kidney disease (CKD) and treatment of diabetic macular edema (DME). The retrospective 2-year cohort study included eyes with DME confirmed using spectral-domain optical coherence tomography in Taipei Veterans General Hospital, Taiwan, between 2010 and 2020. All the eyes were treated with an intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) during regular follow-up around 2 years. They were categorized into 3 different groups: an estimated glomerular filtration rate ≥ 60 (mL/min per 1.73 m2) (group A), < 60 (group B), and patients undergoing hemodialysis (group C). The main outcome measures were (1) visual improvement, (2) structural improvement, and (3) the injection frequency of anti-VEGF in the different groups. In this study, 167 eyes from 120 patients were enrolled. Compared with groups B and C, the eyes in group A experienced the only significant visual improvement at month 3, month 6, and month 12 (P = 0.0001, 0.0002, 0.0013, respectively). The presence of subretinal fluid and intraretinal cysts was significantly decreased in groups A and B. In the treatment frequency analysis, the number of injections was the highest in group A and lowest in group C during the study period (P = 0.04). The severity of CKD had an impact on the DME treatment. The less severe CKD was, the greater the visual improvement that could be achieved. In addition, relatively poor renal function required a lower anti-VEGF injection frequency. The active prevention of the progression of CKD may play a key role in DME treatment.

Macular Alterations in a Cohort of Caucasian Patients Affected by Retinitis Pigmentosa

Objectives: Our objective was to investigate the prevalence of macular complications detected by spectral-domain optical coherence tomography (SD-OCT) in a large Caucasian cohort of RP patients, highlight the major alterations in chorioretinal structure, and compare the macular structural changes in eyes affected by retinal dystrophies with those in healthy controls. Methods: This was an observational, retrospective, and cross-sectional study. Three hundred and seven patients with RP were consecutively enrolled and underwent clinical assessment. In particular, SD-OCT images were used to ascertain the morphology of the posterior pole of patients with RP by evaluating the residual ellipsoid zone (EZ), the volume and thickness of the outer nuclear layer (ONLT), and subfoveal choroid thickness (SCT). At the same time, the pathological finding that the patients’ vision was reduced under treatment was analyzed. Results: A total of 436 eyes of 218 patients with RP were studied. Considering all of the eyes studied, 103 had cystoid macular edema (CME) (23.62%), 123 (28.21%) had vitreomacular traction (VMT), and 199 (45.75%) had epiretinal membranes (ERMs). There were also 12 (2.75%) cases of lamellar macular holes (LMHs), of which 3 (1.38% of all patients) cases were bilateral. Only 137 eyes (31.42%) did not have the above-mentioned alterations. SCT was significantly reduced compared to that of the control group (193.03 µm ± 67.90 SD vs. 295 µm ± 69.04 SD), while the foveal central macular thickness (FCMT) was greater (270.91 μm ± 74.04 SD vs. 221 µm ± 37.25 SD). Conclusions: This research highlights the high incidence of macular complications. The results of our study indicate the importance of regular monitoring of RP patients and early intervention to avoid further complications in this group of subjects with severe visual field impairment to avoid further central vision loss.

Optical coherence tomography angiography of peripapillary vessel density in non-arteritic anterior ischemic optic neuropathy and demyelinating optic neuritis

BackgroundIn cases of optic disc edema or a pale optic disc, distinguishing an episode of optic neuritis (ON) from that of non-arteritic anterior ischemic optic neuropathy (NAION) during a clinical examination is challenging. Optical coherence tomography angiography (OCTA) can reveal differences in peripapillary vascular network structures and provide biomarkers for differential diagnosis.MethodsA total of 23 eyes with NAION, 22 eyes with demyelinating ON (DON), and 27 eyes from healthy participants were imaged using OCTA to observe the radial peripapillary capillaries (RPCs). Optical coherence tomography was used to measure peripapillary retinal nerve fiber layer (RNFL) thickness and the macular ganglion cell complex (mGCC). Data for all patients were recorded at 2–3 weeks and more than 3 months after the symptom onset.ResultsA total of 23 affected eyes from 23 patients with NAION (average age 52.17 ± 7.92 years), 22 eyes from 22 patients with demyelinating optic neuritis (DON) (average age 47.88 ± 19.24 years), and 27 eyes from 27 healthy individuals (average age 46.43 ± 14.08 years) were included in the study. There were no significant differences in sex, age, and eye laterality between any two groups (F = 0.968, 0.475, 0.870; p &amp;gt; 0.05). Throughout the course of NAION and DON, the superior RPC, superior mGCC, and peripapillary RNFL decreased with time (p &amp;lt; 0.05). In contrast, the inferotemporal RPC and inferior mGCC did not decrease from the acute to chronic stage in NAION (t = 1.639, 0.834, p = 0.117, 0.413). Compared with the normal group, patients with NAION and DON exhibited a sharp reduction in the average RPC, RNFL, and GCC from the acute to the chronic stage (p &amp;lt; 0.05). Patients with DON exhibited a significant decrease in the inferotemporal RPC and inferior mGCC compared with the patients with NAION (p &amp;lt; 0.05). In contrast, there were no significant differences in the inferior mGCC at the chronic stage between the patients with NAION and those with ON (t = 2.547, p = 0.093).ConclusionVarious structural and microvascular changes were observed in patients with NAION and ON, indicating distinct features of the optic nerve during the different stages of NAION and ON. Peripapillary vascular density, measured using spectral domain OCT (SD-OCT), may be a biomarker to distinguish NAION from ON.

Validation of Inter-Reader Agreement/Consistency for Quantification of Ellipsoid Zone Integrity and Sub-RPE Compartmental Features Across Retinal Diseases

Background: An unmet need exists when clinically assessing retinal and layer-based features of retinal diseases. Therefore, quantification of retinal-layer-thicknesses/fluid volumes using deep-learning-augmented platforms to reproduce human-obtained clinical measurements is needed. Methods: In this analysis, 210 spectral-domain optical coherence tomography (SD-OCT) scans (30 without pathology, 60 dry age-related macular degeneration [AMD], 60 wet AMD, and 60 diabetic macular edema [total 23,625 B-scans]) were included. A fully automated segmentation platform segmented four retinal layers for compartmental assessment (internal limiting membrane, ellipsoid zone [EZ], retinal pigment epithelium [RPE], and Bruch’s membrane). Two certified OCT readers independently completed manual segmentation and B-scan level validation of automated segmentation, with segmentation correction when needed (semi-automated). Certified reader metrics were compared to gold standard metrics using intraclass correlation coefficients (ICCs) to assess overall agreement. Across different diseases, several metrics generated from automated segmentations approached or matched human readers performance. Results: Absolute ICCs for retinal mean thickness measurements showed excellent agreement (range 0.980–0.999) across four cohorts. EZ-RPE thickness values and sub-RPE compartment ICCs demonstrated excellent agreement (ranges of 0.953–0.987 and 0.944–0.997, respectively) for full dataset, dry-AMD, and wet-AMD cohorts. Conclusions: Analyses demonstrated high reliability and consistency of segmentation of outer retinal compartmental features using a completely human/manual approach or a semi-automated approach to segmentation. These results support the critical role that measuring features, such as photoreceptor preservation through EZ integrity, in future clinical trials may optimize clinical care.

Association of subretinal drusenoid deposits and cardiovascular disease

The presence of subretinal drusenoid deposits (SDDs) in patients with age-related macular degeneration (AMD) appears to be correlated with cardiovascular disease (CVD) and may serve as a useful tool for predicting certain forms of CVD. Here, we tested this hypothesis by examining whether patients with AMD with SDDs are more likely to have a cardiovascular-related condition and/or undergo a cardiovascular procedure. This is a retrospective cohort study. We included a total of 597 patients with AMD either with SDDs (n = 332) or without SDDs (n = 265). All patients underwent spectral-domain optical coherence tomography (SD-OCT). The SD-OCT scans were annotated by masked, experienced graders. We also extracted data from the patients’ electronic medical records (EMRs), including patient demographics, cardiovascular diagnoses, and CVD-related procedures based on ICD-9 codes. AMD patients with SDDs were more likely to be diagnosed with CVD or undergo a cardiovascular procedure compared to AMD patients without SDDs, particularly percutaneous transluminal coronary angioplasty (PTCA; OR 2.73, 95% CI [1.21, 6.13], p = 0.02). Multivariate analysis confirmed the association between the presence of SDDs and a background of PTCA in the presence of other covariates. These data suggest that the presence of SDDs in patients with AMD correlates with certain severe cardiovascular conditions; SDDs and CVD may share common pathogenic pathways.

Advancements in equine ophthalmic imaging enhance understanding of ocular and orbital anatomy and disease in standing sedated horses.

To review data on the advances in equine ophthalmic imaging that have been made during the past 5 years and highlight advantages of using multiple imaging modalities to improve clinical observational skills and improve diagnostic accuracy. A literature review from 2019 through 2024 of equine ophthalmic digital photography, fundus photography, ocular and orbital ultrasonography (US), ultrasound biomicroscopy (UBM), confocal microscopy (CM), spectral domain optical coherence tomography (SD-OCT), radiography, CT, and MRI. Digital photography remains the cornerstone of equine ophthalmic imaging for documenting examination findings, sharing information with colleagues, and consulting with specialists. Digital images also allow for in-depth postexamination review and evaluation, often revealing subtleties that may have otherwise gone undetected during the ophthalmic examination. Advanced imaging modalities are being used more frequently in equine ophthalmology, especially those that can be used with the horses standing under sedation, including US, UBM, SD-OCT, CM, and CT. Advances in equine ophthalmic imaging have led to many new clinical discoveries and to an increase in our knowledge of ocular anatomy and diseases in the horse. Many of these advanced diagnostic imaging modalities, such as MRI, CT, SD-OCT, and CM, are cost prohibitive and require substantial operator training to ensure proficiency. However, their availability in tertiary referral centers, such as veterinary teaching hospitals and large equine clinics/practices, is becoming more widespread. Advanced equine ophthalmic imaging data contributes substantially to our general understanding of clinical and applied anatomy and improves our understanding of the underlying pathogenesis associated with specific diseases.

Comparison of subfoveal choroidal thickness in pre-eclamptic, healthy pregnant, and non-pregnant women.

The purpose of the study was to compare the choroidal thickness (CT) in pre-eclamptic (PE), healthy pregnant, and age-matched healthy non-pregnant females by spectral-domain optical coherence tomography (SD-OCT) and to investigate any possible correlation between subfoveal CT (SFCT) and mean arterial pressure (MAP) in PE. This was a hospital-based, comparative study. A total of 90 females (30 in each group) aged 20-40 years were recruited prospectively over 1 year. Females with refractive error beyond ±3 D, intraocular pressure >21 mmHg, prior ocular trauma or surgeries, systemic diseases, pregnancy-related complications (except PE), and poor OCT scans were excluded. Following comprehensive ophthalmic evaluation, CT was measured bilaterally using SD-OCT (EDI) at the subfoveal region and at 1500 μm nasal and temporal to fovea. Systolic and diastolic blood pressures were recorded in all. The PE group had significantly thinner choroid (SFCT: 337.5 ± 49.8 OD, 333.0 ± 50.8 OS) as compared to the healthy non-pregnant group (SFCT: 351.6 ± 34.4 OD, 365.3 ± 33.6 OS) and healthy pregnant group (SFCT: 374.2 ± 44.1 OD, 377.2 ± 49.5 OS) (P < 0.05) in all locations (nasal, temporal, and subfoveal) in both eyes (except for OD nasal CT). However, there was no significant correlation between SFCT and MAP in the PE group. Significantly lower CT in PE without any direct correlation between SFCT and MAP may implicate that choroidal thinning in PE is governed by multifactorial choroidal vasospasm and endothelial dysfunction, instead of MAP solely.

Does Laser Iridotomy Cause Secondary Epiretinal Membrane?

This study aimed to determine the frequency of epiretinal membrane (ERM) in the long term after neodymium-doped yttrium aluminum garnet laser iridotomy (LI) using spectral domain optical coherence tomography (SD-OCT). This retrospective study included 94 eyes that underwent LI for primary angle-closure glaucoma, were followed for at least 4 years, and had no ERM before the procedure. The control group consisted of 66 eyes that were followed for suspected glaucoma did not have a previous ERM. We compared the ERM frequencies of the groups at the last visit. Additionally, ERM frequencies were compared between those who had cataract surgery in the post-LI period and those who did not. After a follow-up period of at least 4 years, ERM developed in 36 of 94 eyes (38.2%) in the LI group. Of these, 32 were stage 1 ERM (34.0%) and 4 were stage 2 ERM (4.2%). In the control group, ERM developed in 13 of 66 eyes (19.6%), 12 of which were stage 1 ERM (18.1%) and 1 was stage 2 ERM (1.5%) (p=0.012). ERM developed in 14 of 32 eyes (43.7%) who underwent phacoemulsification surgery after LI and in 22 of 62 eyes (35.4%) that underwent only LI without subsequent cataract surgery (p=0.435). ERM developed significantly more frequently in the 62 phakic eyes that underwent only LI than in the eyes in the control group (p=0.045). LI appears to be a predisposing factor for the development of ERM, regardless of subsequent cataract surgery.

Comparison of ganglion cell-inner plexiform layer thickness among patients with intermittent exotropia according to fixation preference: a retrospective observational study.

This study was performed to compare the thickness of the ganglion cell-inner plexiform layer (GCIPL) depending on the presence or absence of fixation preference in patients with intermittent exotropia (IXT) with refractive values close to emmetropia and with no amblyopia. The study recruited pediatric patients diagnosed with IXT with a spherical equivalent within ±1.25 diopter and no amblyopia. The patients were categorized into two groups: a monocular exotropia group with fixation preference and an alternating exotropia group without fixation preference. GCIPL thickness was measured using spectral domain optical coherence tomography, and the macula was divided into nine sectors according to the Early Treatment Diabetic Retinopathy Study (ETDRS). GCIPL thickness in each sector was compared between the monocular and alternating exotropia groups. In the monocular exotropia group, GCIPL thickness was significantly thinner in the dominant eye than in the nondominant eye in the S1 sector (91.2±7.4 μm vs. 93.3±5.2 μm, p=0.019). However, in the alternating exotropia group, there were no significant differences between the eyes across all ETDRS sectors. When comparing the interocular differences in GCIPL thickness between the two groups, the monocular exotropia group (absolute value of the dominant eye minus the nondominant eye) exhibited significantly greater differences in several ETDRS sectors than the alternating exotropia group (absolute value of the right eye minus the left eye). The significant interocular difference in GCIPL thickness in the monocular exotropia group suggests that fixation preference may influence the anatomical structure of the macula in patients with IXT.

Comparative evaluation of OCT with OCTA changes at the optic disc and macula in glaucoma suspect and early glaucoma.

To compare the diagnostic ability of macular ganglion cell inner plexiform layer (mGCIPL) and peripapillary retinal nerve fiber layer (pRNFL) thickness on optical coherence tomography (OCT) and macular and peripapillary perfusion changes using OCT angiography (OCTA) in glaucoma suspect and early primary open angle glaucoma (POAG). Ninety patients (30 normal, 30 glaucoma suspects, and 30 early POAG) were recruited in this cross-sectional, prospective study. The average thickness of mGCIPL and pRNFL on spectral domain-OCT and macular vessel density (VD), optic nerve head (ONH) perfusion, and ONH flux index (FI) on OCTA were evaluated for early diagnosis of glaucoma. Macular VD, ONH perfusion, and ONH FI were significantly reduced in early POAG eyes compared to normal. The best correlation was observed between ONH FI and the average RNFL in both glaucoma suspects (r = 0.47, P < 0.01) and early POAG patients (r = 0.53, P < 0.01). Out of all the measured OCTA parameters, only ONH perfusion was significantly lower in glaucomatous eyes compared to glaucoma suspects (P < 0.001). Average GCIPL (0.82) and macular VD (0.76) had the highest area under the receiver operating characteristic (AUROC) curve value among all the OCT and OCTA parameters, respectively, for differentiating glaucoma suspects from controls. Rim area (0.92) and ONH FI (0.81) had the highest AUROC value among all the OCT and OCTA parameters for differentiating early POAG patients from controls. OCTA vascular parameters had a good correlation with structural damage both at the disc and the macula. OCT parameters were superior to OCTA parameters for diagnosis of glaucoma, although OCTA parameters are deranged very early in the disease.

Multilayered Inverted Internal Limiting Membrane Flap Technique in Optic Disc Pit Maculopathy.

To evaluate the anatomical and visual outcomes of the multilayered inverted internal limiting membrane (ML-ILM) flap technique in the treatment of optic disc pit maculopathy (ODPM). In this retrospective interventional case series, medical records and macular spectral-domain optical coherence tomography images of patients who underwent combined pars plana vitrectomy with ML-ILM flap surgery for ODPM were analyzed. Best-corrected visual acuity (BCVA) and central macular thickness (CMT) at postoperative 6 months were compared with baseline findings. Intraoperative and postoperative complications, fluid resolution time, and recurrence during follow-up were recorded. Five eyes of 5 patients with ODPM were included in the study. According to the preoperative macular fluid characteristics, 2 patients had only intraretinal fluid, while 3 patients had intraretinal and subretinal fluid. The preoperative median BCVA was 1.0 logarithm of the minimum angle of resolution (logMAR) (range, 1.0-1.3 logMAR), and the CMT was 560 μm (range, 452-667 μm). At the 6-month postoperative follow-up, the median BCVA was 0.40 logMAR (range, 0.1-0.7 logMAR), and CMT was 315 μm (range, 265-326 μm) (p=0.042 and p=0.043, respectively). During the 6-month follow-up period, no recurrence or full-thickness macular hole formation was observed. The ML-ILM flap technique is a preferable surgical option to achieve both high anatomical and functional success and flap stabilization.

The no-retina-touch technique: vitrectomy and platelet-rich plasma in the treatment of lamellar macular hole. New insights into pathogenesis.

To explore the use of autologous platelet-rich plasma (PRP) as a potential therapeutic adjuvant strategy for treating degenerative lamellar macular holes (LMHs). A prospective interventional case series. Seven consecutive patients (8 eyes) with a diagnosis of LMH underwent a pars-plana vitrectomy with PRP injection under air tamponade. Anatomical results based on spectral domain optical coherence tomography (SD-OCT) and functional results, in terms of best corrected visual acuity (BCVA) and reading performance, were analyzed. At 12 months postoperatively, 7 out of 8 eyes (88%) presented a complete closure of the LMH. The ellipsoid zone (EZ) was restored in 3 eyes (37.5%). The mean (±SD) postoperative BCVA was 0.39 (±0.56) LogMAR, resulting in a statistically significant visual acuity improvement (p = 0.007). The mean (±SD) maximum reading speed (MaxRS) improved to 133.48 (±41.47) wpm, with a significant increase compared to the baseline (p = 0.029). The mean (±SD) reading acuity score (RA score) resulted in 0.44 (±0.04) LogRAD, with an improvement in reading acuity that did not reach statistical significance (p = 0.129). The utilization of the PRP technique with a no-retina-touch approach safeguards the delicate retinal tissues, minimizing the possibility of iatrogenic trauma or post-operative complications, while maintaining a high rate of efficacy in enabling the improvement of the foveal defect in lamellar macular holes.

Tuning and Timing of Organ of Corti Vibrations at the Apex of the Intact Chinchilla Cochlea.

The goal of this research was to record sound-evoked vibrations in the organ of Corti at the apex of the intact cochlea of the chinchilla, an animal with a frequency hearing range similar to that of humans. Twelve adult anesthetized chinchillas of either sex were used. Measurements of sound-evoked vibrations of the intact organ of Corti (OoC) were performed using optical coherence tomography (OCT). Acoustic stimuli consisted of single tones of 1-s duration. OoC vibrations were recorded using a Telesto Spectral Domain OCT system (Thorlabs GmbH, Germany) and ThorImage® OCT version 5.4.2 (Thorlabs GmbH, Germany). Further analysis of the output of the ThorImage software was performed by ad hoc programs written using Matlab® R2020b. Recordings were performed at several OoC sites extending from the Hensen's cell region to the vicinity of the basilar membrane (BM). The measurement angle between the optical axis of the OCT system and the BM was approximately 45°. Under that experimental condition, delays among the different OoC locations indicate that BM motion occurs earlier than at other sites. At all OoC sites, sound-evoked vibrations grow nonlinearly with stimulus level at compressive rates. The sharpness of tuning of OoC vibrations increases with stimulus level and death. Iso-velocity curves as a function of frequency are well-tuned around 500 Hz and closely resemble threshold tuning curves of chinchilla auditory-nerve fibers with similar characteristic frequencies. The nonlinear processing of sounds at the apex of the chinchilla cochlea differs significantly from the processing of sounds at the base of the cochlea in the same species.

Distribution and associated factors of choroidal thickness in highly myopic eyes-a real-world study based on a Chinese population.

To measure the subfoveal choroidal thickness (SFCT) in highly myopic eyes at different locations using enhanced depth imaging spectral-domain optical coherence tomography (EDI SD-OCT). To identify the ocular and systemic risk factors associated with choroidal thinning in high myopia. Based on the Beijing Eye Study, a detailed ophthalmic examination was performed including EDI SD-OCT for the measurement of SFCT. OCT images were obtained from 103 highly myopic eyes (≥ -6.00 dioptres) and 227 normal eyes randomly selected from the baseline population, matched for age and sex. The mean SFCT was 110.6 ± 85.2 μm in highly myopic eyes (range, 3-395 μm). Mean regional choroidal thickness was lowest on the nasal and inferior sides of the macula, and slightly higher on the temporal and superior sides than at the fovea. On multivariate analysis, SFCT was associated with age (b = -0.48; P < 0.001), axial length (b = -0.44; P < 0.001), gender (b = -0.31; P < 0.05) and staphyloma (b = -0.26; P = 0.05). In highly myopic eyes, SFCT decreased by 5.1 μm/year of age, by 9.2 µm/D of myopia, and by 22.6 µm/mm of axial length. The SFCT decreases with age and increased axial length in highly myopic eyes. The formation of a posterior staphyloma has been identified as a major contributor to choroidal thinning and is therefore a reliable indicator for risk management. The involvement of choroidal abnormalities may be a significant factor in the development of myopic degeneration.

Comparative analysis of a novel spectral-domain OCT biometer versus swept-source OCT or OLCR biometer in healthy pediatric ocular biometry

With the advancements in ocular biometric technology, there have been significant improvements in accurately and efficiently measuring ocular parameters. The aim of this study is to compare the reliability of biometric parameters obtained using a new frequency-domain optical coherence tomography (SD-OCT) biometer with the measurements obtained from swept-source OCT (SS-OCT) and optical low coherence reflectometry (OLCR) biometers. This study employed an observational cross-sectional design. Measurements of axial length (AL), flat and steep corneal keratometry (K1 and K2), and central corneal thickness (CCT) obtained using the The Colombo IOL were compared with those obtained with the IOLMaster 700 and SW-9000 devices. The agreement were evaluated using intraclass correlation coefficient (ICC) and Bland–Altman analyses. The differences of the measurements of the three increments were assessed by one-way ANONA. 73 right eyes of 73 healthy pediatric subjects were analyzed. The AL difference measured by Colombo IOL compared with IOLmaster700 and SW-9000 were 0.00 ± 0.02 mm and − 0.07 ± 0.05 mm, respectively (P > 0.05, ANOVA). There was no statistically significant difference in CCT, K1, and K2 among the three instruments (all P > 0.05, ANOVA). The ICC values for AL, K1, K2, and CCT were 0.999, 0.996, 0.995, and 0.998, respectively. The Bland-Altman analysis showed an agreement of AL, K1, K2, and CCT with Colombo IOL and IOLMaster 700 spanned over 0.08 mm, 0.71D, 0.69D, and 12.17 μm, respectively. The agreement of AL, K1, K2, and CCT with Colombo IOL and SW-9000 spanned approximate 0.21 mm, 0.75D, 1.06D, and 14.37 μm, respectively. The new SD-OCT biometer and the SS-OCT biometer showed strong agreement in measuring AL and CCT in healthy pediatric subjects. This supports the reliability of the new SD-OCT biometer as an alternative for assessing these parameters. However, K1 and K2 could not be used interchangeably in clinical practice. Further research is needed to explore their applicability in different clinical settings and patient populations."light" />