Current Eye Research最新文献

Purpose: When examining the ocular surface, patients are required to look straight ahead and the effects of vertical eye movement on tear film behavior are not considered despite it being natural and common to change gaze without blinking. This exposes parts of the bulbar conjunctiva previously covered by the eyelids and therefore not covered by the tear film during the preceding blink. This study investigates how the tear film behaves when presented with newly exposed areas of ocular surface due to vertical eye movements.

Methods: The tear film dynamics of a sequence of vertical open-eye gaze maneuvers (upgaze-downgaze) were studied in 15 participants with no ocular surface related complaints (OSDI <13) using the TearView infrared camera system. TearView detects the tear film based on natural infrared radiation emitted from the ocular surface. Interferometry was used to examine lipid layer behavior. In a subgroup (n = 3), eyelids were mechanically lifted using a finger to reveal bulbar conjunctiva.

Results: Vertical eye movements exposed bulbar conjunctiva not covered by the tear film during the preceding blink. The fully formed tear film reacted by spreading toward the newly uncovered ocular surface area, thereby recoating it. This also occurred when the eyelids were mechanically lifted to reveal ocular surface previously beneath the eyelids. No apparent flow occurred from the menisci onto the ocular surface.

Conclusions: The fully formed tear film is isolated from the meniscal tear and meibum reservoirs (a completely perched tear film). This tear film spontaneously spreads to cover ocular surface area that is newly exposed during vertical eye movements.

Purpose: Acanthamoeba keratitis (AK) is a sight threatening infection of the cornea caused by opportunistic pathogens belonging to the genus Acanthamoeba. AK is commonly associated with contact lens use, and treatments are currently limited and ineffective. As such, the emergence of antimicrobial resistance in Acanthamoeba poses a significant challenge to the management of AK. This study investigates the development of polyhexamethylene biguanide (PHMB) resistance, a frontline therapeutic, in Acanthamoeba trophozoites and explores potential cross-resistance to hexamidine and voriconazole.

Methods: Acanthamoeba castellanii trophozoites were exposed and maintained in PHMB starting at 2 µg/mL and increasing upon reaching confluence. Cells were subsequently exposed to incrementally higher doses of PHMB in a stepwise manner (2, 4, 5.5, and 7 µg/mL). When sustained growth under PHMB exposure was observed, morphology was assessed by imaging flow cytometry and susceptibility assays were performed by incubating resistant strains with PHMB, hexamidine, and voriconazole for 24 h, and viability determined using alamarBlue.

Results: Trophozoites surviving exposure at 2 µg/mL reached confluence within 11 days. Stepwise increases to 4 µg/mL, 5.5 µg/mL, and 7 µg/mL were achieved within 6-7 days at each stage. PHMB-resistant Acanthamoeba strains exhibited a 9-fold increase in resistance to PHMB relative to naïve cells, alongside significant cross-resistance to voriconazole (159-fold) and hexamidine (8.4-fold). No significant change in trophozoite or cyst morphology was observed relative to the naïve cell line.

Conclusions: These findings represent the first known laboratory-induced PHMB-resistant Acanthamoeba strains, raising concerns regarding the longevity of current therapeutic options and the potential for cross-resistance to alternative treatments. This highlights the need for clinical vigilance and further investigation into the molecular mechanisms of resistance to better inform treatment strategies.

Purpose: Retinopathy of prematurity is a leading cause of childhood blindness, with several predisposing factors, including prematurity and oxygen therapy. This study examines nucleated red blood cell (NRBC) counts at birth in preterm neonates and compares those who developed ROP with those who did not.

Methods: This case-control study included 143 preterm neonates (birth weight <1500 g and/or gestational age <32 weeks) born at Ghaem Hospital, Mashhad, between 2017 and 2020. Umbilical cord blood samples were collected to measure NRBC counts per 100 white blood cells. Neonatal characteristics (birth weight, sex, gestational age, Apgar scores), maternal history (age, pregnancy complications, mode of delivery, parity), and laboratory findings were recorded. Follow-up assessments continued until discharge, with ophthalmologic evaluation for ROP at 32 weeks of gestational age or four weeks post-birth. The control group consisted of preterm neonates without ROP.

Results: Among the 143 neonates studied, 102 (71.3%) developed ROP, while 41 (28.7%) did not. Significant differences were observed between the two groups in NRBC percentage (p = 0.009) and fifth-minute Apgar score (p = 0.002).

Conclusions: Elevated umbilical cord NRBC counts, alongside other clinical markers, may serve as a predictive factor for ROP and its severity.

Introduction: Wearable light sensors allow for a more objective classification of a child's habitual light environment. The aim of this study was to develop an optimal illuminance and/or RGB irradiance thresholds as a proxy for distinguishing between indoor and outdoor environments through empirical analysis of data collected with the Actiwatch Spectrum PRO, as an example of wearable light-sensing technology.

Methods: Six participants, aged 18-22 y, wore an Actiwatch Spectrum PRO, for two consecutive days as they went about their daily activities. The Actiwatch was configured to record at 30 s epochs, both overall illuminance (lux) and irradiance (µW/cm2), for each of its three wavelength channels (R, G, B). Using the Actiwatch's scoring feature, participants indicated changes in their environment and its type, i.e. indoors or outdoors. For each individual dataset, mean illuminance, as well as mean red, green, and blue irradiances were calculated for each event, i.e. interval spent in a particular environment. Criteria for distinguishing between indoor and outdoor environments were evaluated using ROC analyses.

Results: Based on the collected data, a 1000 lux white light threshold, which has been commonly used to distinguish between outdoor and indoor settings, resulted in significant misclassification of reported outdoor events (sensitivity: 43.5%, specificity: 93.6%). The use of two time-dependent red light irradiance thresholds covering sunrise to 2 pm, and 2 pm to sunset, proved to more reliably identify outdoor settings (sensitivity: 85.1%, specificity: 82.6%).

Conclusion: In this small-scale study of the Actiwatch Spectrum Pro, derived red light irradiance thresholds out performed the more commonly used 1000 lux white light threshold in correctly classifying indoor and outdoor environments. In this context, the potential utility of wavelength-dependent irradiance cutoff values warrants further investigation, with due consideration to study-specific differences in geographic locations, climate and season.

Purpose: To systematically explore the multi-dimensional mechanisms of the epigenetic regulatory network in uveitis, address the challenges faced by traditional treatments, and provide new ideas and directions for the precise diagnosis and treatment of this disease.

Methods: A systematic review was conducted on the epigenetic regulation in uveitis, focusing on analyzing abnormal DNA methylation, dynamic balance of histone modifications, disease-specific regulatory characteristics of non-coding RNAs, as well as their applications in diagnosis, prognosis assessment, and targeted treatment strategies.

Results: The epigenetic regulatory network in uveitis includes abnormal DNA methylation driving immune imbalance, histone modification dynamics regulating inflammatory signal amplification, and disease-specific non-coding RNAs. Epigenetics shows value in uveitis diagnosis, prognosis, and targeted treatments, with relevant scientific challenges analyzed.

Conclusion: This review clarifies the roles of epigenetics in uveitis, offering new insights for precise diagnosis and treatment, which is conducive to advancing research and clinical practice in the field.

Purpose: To evaluate the safety, efficacy, predictability, and stability of phakic refractive lens (PRL) implantation for the correction of super-high myopia.

Methods: This four-center prospective clinical study included 30 eyes from 16 myopic patients who underwent PRL implantation. The patients were followed up for one year, with evaluations of uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refraction, intraocular pressure (IOP), vault, endothelial cell density (ECD), and axial length.

Results: One year postoperatively, eight eyes (27%) achieved a UDVA of 20/20 or better, and 21 eyes (70%) achieved a UDVA of 20/25 or better. The CDVA improved by one line in 22 eyes (73%), with one eye experiencing a loss of CDVA. The mean efficacy and safety index at one year were 1.30 ± 0.49 and 1.61 ± 0.32, respectively. No significant change was observed in the mean refractive spherical equivalent between one week and one year postoperatively. The axial length remained stable pre- and postoperatively. IOP increased significantly at 1 d and 1 week postoperatively (p = 0.002 and p < 0.001, respectively) but returned to preoperative levels by 1 month. ECD showed no significant change pre- and postoperatively except that 5 eyes from 4 patients had a postoperative ECD below 2000 cells/mm² caused by surgical trauma. The mean vault was 393.05 ± 243.54 µm at one week and 385.68 ± 157.41 µm at one year, showing no significant change.

Conclusion: PRL implantation for correction of super-high myopia demonstrated good safety, efficacy, predictability, and stability.

Purpose: The aim of this study was to develop a 3D-printed eye model to simulate measuring intraocular pressure (IOP) as a training device, and to assess the correlation between measured IOP using common clinical techniques and actual internal pressure.

Methods: The IOP eye model was designed using CAD software and printed with a resin stereolithography (SLA) 3D-printer (Formlabs 3B, Formlabs Inc., MA, USA). Two clinical instruments, Tono-pen (Tono-Pen AVIA, Reichert Ophthalmic Instruments, USA), and Perkins hand-held tonometer (Clement Clarke Perkins Tonometer Mk2, Vision Equipment Inc., USA) were used for IOP measurements of the model. The pressure within the model was adjusted between 7 to 55 mmHg at 5 mmHg increments, and the IOP values of the tonometry were correlated to the internal pressure displayed on the gauge.

Results: The IOP model could reliably produce internal pressure from 0 to 56 mmHg. The results showed that the Tono-pen measurements above 7 mmHg were closely correlated to the internal pressure obtained from the pressure gauge (Pearson r = 0.99, p < 0.0001). However, aligning the mires and measuring IOP accurately with the Perkins device was challenging.

Conclusion: The 3D-printed eye model was able to strongly correlate IOP readings taken with a Tono-pen with internal pressure measured by a pressure gauge. The internal pressure of this model can be regulated and is envisioned as a potential model for practicing tonometry at different ranges of pressure.

Purpose: Sex hormone changes, often occurring during menopause, are implicated in meibomian gland dysfunction (MGD) and evaporative dry eye disease (DED). This study aimed to evaluate whether menopausal status affects the treatment outcomes of perfluorohexyloctane eye drops.

Methods: This post hoc analysis used data from a phase 3 trial (NCT05515471) of perfluorohexyloctane eye drops in patients with DED associated with MGD. The efficacy and safety of perfluorohexyloctane compared with 0.6% saline were evaluated within each menopausal status subgroup (premenopausal or postmenopausal), and the interaction between treatment and menopausal status was assessed.

Results: In total, 245 women (94 postmenopausal and 151 premenopausal) were included. In the postmenopausal subgroup, the propensity score weighted least-squares mean differences (LSMD) in changes from baseline to day 57 in total corneal fluorescein staining (tCFS) score and eye dryness score (EDS) between perfluorohexyloctane and saline were -1.0 (95% CI, -2.0, 0.0) and -7.9 (95% CI, -15.6, -0.2), respectively. In the premenopausal subgroup, the propensity score weighted LSMD in changes from baseline to day 57 in tCFS score and EDS were -1.4 (95% CI, -2.3, -0.5) and -14.0 (95% CI, -20.3, -7.8), respectively. Both subgroups showed improvements in some DED symptoms. No statistically significant interaction was observed between menopausal status and treatment across all measured outcomes. Perfluorohexyloctane was well tolerable in both subgroups.

Conclusions: Perfluorohexyloctane eye drops improved signs and symptoms of DED associated with MGD and were safe in both postmenopausal and premenopausal women. Further studies are needed to confirm the influence of menopausal status on perfluorohexyloctane efficacy.

Trial registration: ClinicalTrials.gov identifier, NCT05515471.

Purpose: To study the correlation between uncorrected distance visual acuity (UCVA) and myopic refractive error among school-aged children.

Methods: The North India Myopia study is a prospective cohort study in which school children were screened for refractive error. These children were subsequently followed up to note the incidence and progression of myopia. The methodology of the study is as previously described. Children with UCVA < 3/60 were excluded for this analysis, since they are more likely to be associated with other ocular pathologies.

Results: Of the 9884 children screened, 1463 children fulfilled the inclusion criteria for this analysis. UCVA was plotted against the mean prescribed Spherical equivalent (SE), with a 95% confidence interval. Marginal predictions of prescribed power according to UCVA were calculated using linear regression, enabling the development of a nomogram to estimate the closest SE based on UCVA.

Conclusion: There is a steady correlation between the UCVA and degree of myopic refractive error among school going children. This correlation has been utilized to develop this nomogram that may help predict myopic refractive error on the basis of uncorrected visual acuity. Large scale studies are needed for the validation of this nomogram in different populations.