Iris neovascularization and neurotrophic keratopathy following ultrasound cycloplasty in refractory glaucoma: case series.

BACKGROUND: Ultrasound cycloplasty is a noninvasive surgery used to reduce intraocular pressure in patients with glaucoma, with fewer severe complications. This report presents several cases of iris neovascularization and neurotrophic keratopathy following ultrasound cycloplasty. CASE PRESENTATION: Six patients diagnosed with refractory glaucoma underwent ultrasound cycloplasty at our clinic. Three cases developed iris neovascularization at postoperative day 3, week 2 and week 4 respectively, with intraocular pressure ranging from 12 to 24 mmHg. The other three cases developed neurotrophic keratopathy at postoperative week 3, week 6 and week 8 which completely healed within 60 days. CONCLUSIONS: Iris neovascularization and neurotrophic keratopathy can be triggered after ultrasound cycloplasty, which are uncommon and self-limited but potentially vision-threatening. Preoperative risk assessment and regular postoperative follow-up are recommended to manage complications effectively.

A New Contact Lens Sensor System for Continuous Intraocular Pressure Monitoring: Evaluation of Safety and Tolerability.

PURPOSE: To assess the safety and tolerability of a new contact lens sensor (CLS) system for continuous 3- and 24-hr intraocular pressure (IOP) monitoring in human eyes. METHODS: Twenty-five subjects were recruited for 3-hr IOP measurement by CLS. Corneal fluorescein staining (CFS) scores were evaluated before and after measurement. Then, 30 participants (10 normal subjects and 20 glaucoma patients) were recruited for 24-hr IOP monitoring. Ocular surface disease index (OSDI) was assessed before and one day after measurement. Contact lens dry eye questionnaire-8 was assessed immediately after measurement. Visual analog scale of discomfort was measured before, immediately after, and one day after measurement. Best-corrected visual acuity (BCVA), tear break-up time (TBUT), and CFS were assessed before, immediately after, and 1 day after measurement. RESULTS: All participants completed 3- or 24-hr IOP measurement by CLS. Corneal fluorescein staining increased from 0.6±0.7 to 2.4±1.5 after 3-hr IOP measurement ( P <0.001). For participants undergoing 24-hr IOP monitoring, OSDI increased from 9.1±9.7 to 18.0±12.4 ( P =0.001). CLDEQ-8 score was 11.6±5.8. Visual analog scale increased from 11.1±14.2 to 35.2±21.8 after measurement ( P <0.001) and decreased to 26.7±18.4 one day later ( P <0.001 compared with baseline). BCVA decreased from 1.0±0.01 to 0.8±0.1 ( P <0.001) and returned to 0.9±0.1 after one day ( P <0.001 compared with baseline). TBUT decreased from 5.1±3.9 to 2.6±1.5 s ( P =0.001) and returned to 4.8±2.5 s ( P =0.465 compared with baseline). Corneal fluorescein staining increased from 0.7±0.9 to 4.3±0.8 ( P <0.001) and dropped to 0.8±0.7 ( P =0.599 compared with baseline). No significant difference was found for all variations of indicators between normal subjects and glaucoma patients ( P >0.1 for all comparisons). CONCLUSIONS: The CLS shows a great potential for a safe and tolerable 24-hr IOP monitoring in normal subjects and glaucoma patients. Clinical attention to the worsening signs and symptoms after measurement is required.

Nintedanib inhibits TGF-ß-induced myofibroblast transdifferentiation in human Tenon's fibroblasts.

Purpose: This study aimed to investigate the effect of nintedanib on the conversion of human Tenon's fibroblasts (HTFs) into myofibroblasts and reveal the molecular mechanisms involved. Methods: Primary cultured HTFs were incubated with transforming growth factor ß1 (TGF-ß1) alone or combined with nintedanib, and cell proliferation and migration were measured by cell counting kit-8 (CCK8) and the scratch wound assay, respectively. HTF contractility was evaluated with a 3D collagen contraction assay. The mRNA and protein levels of α smooth muscle actin (α-SMA) and Snail and the phosphorylation levels of Smad2/3, p38 mitogen-activated protein kinase (p38MAPK), and extracellular signal-regulated kinase ½ (ERK1/2) were determined by quantitative reverse transcription polymerase chain reaction (RT-PCR), western blot, and immunofluorescence staining. Results: Nintedanib inhibited the proliferation and migration of HTFs in a dose-dependent manner. Furthermore, nintedanib prevented HTF myofibroblast differentiation via downregulation of mRNA and protein expression of α-SMA and Snail. A three-dimensional (3D) collagen gel contraction assay demonstrated that nintedanib effectively inhibits myofibroblast contraction induced by TGF-ß1. Mechanistically, we revealed that nintedanib reduces the TGF-ß1-induced phosphorylation of Smad2/3, p38MAPK, and ERK1/2, suggesting that nintedanib acts through both classic and nonclassic signaling pathways of TGF-ß1 to prevent HTF activation. Conclusions: Our study provides new evidence that nintedanib has potent antifibrotic effects in HTFs and suggests that it may be used as a potential therapeutic agent for subconjunctival fibrosis.

Preparation and evaluation of HPMC-based pirfenidone solution in vivo.

CONTEXT: Pirfenidone (PFD) has exhibited therapeutic potential in the treatment of cell proliferative disorders. The previously developed 0.5% water-based PFD eye drops by our team exhibited antiscarring effectiveness and ocular safety but with a limit of short half-life and poor bioavailability. OBJECTIVE: To increase bioavailability of the water-based PFD eye drops, we prepared a viscous solution by adding hydroxypropyl methylcellulose (HPMC, F4M), which acted as a viscosity-enhancer. Subsequently, we compared the HPMC-based PFD solution with the water-based PFD eye drops. MATERIALS AND METHODS: PFD solution with 1% HPMC (w/v) was prepared, and the viscosities at different shear rates were measured to investigate its rheology. PFD concentrations in the tear, aqueous humor, conjunctiva, cornea, and sclerae of New Zealand rabbits were detected at different time points with high-performance liquid chromatography (HPLC) following single instillation of the 0.5% PFD (w/v) water-based eye drops or HPMC-based solution. RESULTS: Compared with the 0.5% water-based PFD eye drops, the HPMC-based solution increased the PFD levels in tears and prolonged the residence time from 10 to more than 20 min (p < .01). Consequently, the concentrations of PFD in aqueous humor, conjunctiva, cornea, and sclera were elevated to varying degrees until 90 min after topical administration. CONCLUSIONS: The developed formulation possesses a same readily administration and simple preparation as the PFD eye drops; however, the HPMC-based solution exhibited the higher bioavailability.

Prevalence, types and awareness of glaucoma in a multi-ethnic population in rural China: the Yunnan Minority Eye Study.

PURPOSE: To determine the prevalence, types and awareness of glaucoma in a rural community in China and to examine possible ethnic variations. METHODS: The Yunnan Minority Eye Study was a multi-ethnic community-based eye survey using random cluster sampling strategies. 2133 Bai, 2205 Han and 2208 Yi Chinese aged 50 years or older participated in this study. Glaucoma including primary open-angle glaucoma (POAG), primary angle-closure glaucoma (PACG) and secondary glaucoma was defined based on the International Society of Geographical and Epidemiological Ophthalmology criteria. RESULTS: The overall age-standardized prevalence of all glaucoma was 2.6% (95% confidence interval [CI]: 2.2-3.1%) in this population. It was 1.8% (95% CI: 1.1-1.9%) for POAG and 0.5% (95% CI: 0.9-1.6%) for PACG, respectively. Among 29 people with secondary glaucoma, 27 (93%) were blind in at least one eye. The presence of primary open-angle glaucoma was associated with male gender (odds ratio [OR] = 2.94; comparing men with women), Yi ethnicity (OR = 2.27; comparing Yi with Han people), higher IOP (OR = 1.09 per mmHg increase), and the presence of myopia (OR = 1.84). Of the 212 participants with glaucoma, only 38 (18%) were aware of the disease and had been diagnosed previously as having glaucoma or suspected glaucoma. Patients who were better educated tended to be aware of the disease. CONCLUSIONS: Significant ethnic difference in the prevalence of POAG was observed in this study. The low awareness of glaucoma highlights the pressing need to increase public awareness of this potentially blinding condition in rural China.

[A prospective randomized study of selective laser trabeculoplasty (SLT) as a replacement for medical therapy in primary open-angle glaucoma].

OBJECTIVE: To evaluate the efficacy and safety of selective laser trabeculoplasty (SLT) as a replacement for medical therapy in primary open-angle glaucoma (POAG). METHODS: A prospective, randomized, controlled study.SLT treatment with SOLO SLT Nd: YAG laser was provided to 45 participants with advanced POAG (67 eyes, IOP ≤ 21 mmHg, 1 mmHg = 0.133 kPa) under anti-glaucomatous medications control). A table of random numbers was created by simple randomization method. Participants were randomly divided into two groups: the standard-energy group (34 eyes), which received a 270° standard-energy SLT treatment and the sub-threshold energy group (33 eyes), which received a 360° sub-threshold energy treatment. The intraocular pressure (IOP) before and after SLT, daytime IOP curve, dosage of anti-glaucoma drugs and treatment complications were observed, which were be followed up for 6-9 months (average 6.4 months). Two-tailed t-test or paired t test was used when the continuous variables were normal distribution, such as the basic data, daily fluctuations of IOP, laser energy. Non-parametric Mann-Whitney U test or Wilcoxon rank test was used when data was not distributed normally, such as drug category. Chi-square or Fisher's exact test was used when count variables such as success rate and complications were analyzed. RESULTS: The number of anti-glaucomatous drugs used in the standard-energy group and the sub-threshold energy group before SLT was (2.3 ± 0.5) and (2.1 ± 0.4), respectively; whereas, after the last treatment, it reduced to (1.3 ± 0.5) and (1.1 ± 0.3), respectively (Z = -5.477, -5.396; P < 0.05). The success rate of the standard-energy group and the sub-threshold energy group was 91.1%, and 87.9%, respectively, which was not significant different (P = 0.70). Laser treatment was found to reduce the IOP fluctuation during the daytime.IOP fluctuation decreased from (3.6 ± 1.0) mmHg to (2.3 ± 1.0) mmHg in the standard-energy group, and decreased from (3.9 ± 1.4) mmHg to (2.4 ± 0.9) mmHg in the sub-threshold energy group, which was significant different (t = 4.911, 4.679; P < 0.05). The total laser energy of the standard-energy group (47.8 ± 6.0) mJ was higher than the sub-threshold energy group (43.2 ± 5.1) mJ (t = 12.006, 3.233; P < 0.05). However, there was no significant difference in the daily IOP fluctuations, success rate, reduction of medication categories, preoperative and postoperative IOP, and adverse reactions between the two groups. CONCLUSIONS: SLT is a safe and effective replacement for medical therapy in primary open-angle glaucoma treatment. SLT could reduce the applications of anti-glaucoma drugs. There was no significant difference between therapeutic effects of which eyes received 360° sub-threshold energy and 270° standard-energy.

Automatic noninvasive tear breakup time (TBUT) and conventional fluorescent TBUT.

PURPOSE: To compare the effects of different volumes of fluorescein on tear breakup time (FTBUT) and to investigate if and to what extent the tear breakup time determined by an automated noninvasive instrument (NITBUT) differs from FTBUT. METHODS: Twenty-four healthy volunteers were recruited to the study. Fluorescent tear breakup time was measured with different volumes of fluorescein solution delivered by either glass rod or objective directly by fluorescein strip. Noninvasive tear breakup time was measured with a noninvasive instrument (Oculus Keratograph 5M, Germany; K5). The average levels of the tear breakup times (TBUTs) and the variability of the successive recordings for each measurement were compared. RESULTS: Increasing the volume of fluorescein delivered from 1 to 7 µl lengthened FTBUT by a mean ratio of 1.26-fold (p = 0.019) for the glass rod technique. No significant difference was detected in the FTBUT measured by the fluorescein strip technique when the delivered volume was increased from 4.5 to 7 µl. The variability of successive recordings was stable across the tested volumes for both techniques. Noninvasive tear breakup time determined by K5 was significantly longer than FTBUTs (mean difference: 3.90 seconds, p = 0.003 and 4.12 seconds, p = 0.002, respectively). Although no significant difference was detected in the average SD for successive recordings among K5 and the other two invasive techniques (p = 0.325), the variability of NITBUT was found significantly dependent on the observed TBUT (r = 0.532, p = 0.007). CONCLUSIONS: The Oculus Keratograph 5M usually produced substantially longer TBUT compared with invasive techniques tested. The variability of readings by this novel method increased with the values of NITBUT. Given the small sample size in the current experiment, however, these findings need to be confirmed in a larger study.

[Meta-analysis of randomized controlled trials comparing selective laser trabeculoplasty with prostaglandin analogue in the primary treatment of open-angle glaucoma or ocular hypertention].

OBJECTIVE: To compare the efficacy of selective laser trabeculoplasty (SLT) versus prostaglandinanalogue (PGA) in the treatment of open angle glaucoma (OAG) and ocular hypertension (OHT). METHODS: Literature analysis.Systematic review of randomized controlled trials comparing SLT versus PGA, identified by searching literatures including Medline (January, 1966-December, 2012), EMBASE Reviews (January, 1974-December, 2012) OVID Evidence-Based Medicine Reviews (January, 1966-December, 2012), Chinese BioMedical Literature Database SinoMed (January, 1966-December, 2012), and CNKI (January, 1999-December, 2012). RevMan 5.0 was used to do meta-analysis. RESULTS: Three publications reporting 3 trials, 161 participants (231 eyes) with OHT or OAG were included for meta-analysis.IOP reduction favored PGA group, weighted mean difference (WMD) = -0.85[1 mmHg = 0.133 kPa; 95% confidence interval (CI) (-1.43 to -0.27), no significant heterogeneity present (P = 0.82, I² = 0%)].Success rates are equal in two groups [OR = 0.70, 95%CI = (0.49 to 1.19) , no significant heterogeneity present (P = 0.58, I² = 0%)]. Eyes underwent additional antiglaumatous interventions favored SLT group, OR = 1.11 [95%CI = (0.60 to 2.06), significant heterogeneity present, (P = 0.08, I² = 61%)]. CONCLUSIONS: As primary therapy of OAG or OHT, SLT is no more effective than PGA in success rate. IOP reduction affected by SLT is not effective than PGA. Compared with PGA, SLT can reduce the use of anti-glaucoma medications.

Early impairment of magnocellular visual pathways mediated by isolated-check visual evoked potentials in primary open-angle glaucoma: a cross-sectional study.

OBJECTIVE: To explore different performances in the magnocellular (MC) and parvocellular (PC) visual pathways in patients with primary open-angle glaucoma (POAG) and to objectively assess impairment in early stage of POAG. METHODS AND ANALYSIS: This is a cross-sectional study. MC and PC visual pathways were assessed using isolated-check visual evoked potential (ic-VEP). Visual acuity, intraocular pressure, fundus examination, optical coherence tomography and visual field were measured. Signal-to-noise ratios (SNRs), mediated by ic-VEP were recorded. The Spearman's correlation analysis was used to estimate the relationships between visual functions and structures. Receiver-operating-characteristic (ROC) curves were used to estimate the accuracy in detection of early POAG. RESULTS: 60 participants (30 early POAG eyes and 30 age-matched control subjects) were recruited. MC visual pathway showed a non-linear response function, while PC visual pathway was a linear response function as contrast increased. Early POAG eyes exhibited significantly weaker initial contrast gains and lower maximum responses in the MC visual pathway (p=0.001, p=0.004, respectively). The SNRs at 8% and 32% depths of modulation (DOM) were significantly correlated with temporal-side retinal nerve fibre layer (RNFL) thickness in early POAG in MC-biased stimulation (p=0.017, p=0.020, respectively). The areas under ROC of 16% DOM were 0.780 (sensitivity 80.0%, specificity 63.3%) with the cut-off SNR of 2.07. CONCLUSIONS: The MC visual pathway was damaged in the early stage of POAG. The SNRs at 8% and 32% DOM of MC-biased stimulation were significantly correlated with temporal-side RNFL thickness in early POAG, which helped in understanding the mechanisms of visual impairment in the early stage of POAG.

Expression of the SARS-CoV-2 Receptor ACE2 and Protease TMPRSS2 in Ocular Hypertension Eyes of Nonhuman Primate and Human.

PURPOSE: Coronavirus disease 2019 is a disease caused by the novel severe acute respiratory syndrome coronavirus 2. The double-positive of angiotensin-converting enzyme 2 and transmembrane protease serine type 2 have a higher risk of being infected by severe acute respiratory syndrome coronavirus 2. The susceptibility of coronavirus disease 2019 in patients with chronic diseases, especially in different tissues of ocular hypertension eyes like glaucoma, is not yet known. METHODS: An ocular hypertension model was established by laser photocoagulation in rhesus monkeys. The expression of angiotensin-converting enzyme 2 and transmembrane protease serine type 2 in three ocular hypertension eyes and the three control eyes were analyzed using immunofluorescence. RESULTS: No difference was observed between ocular hypertension and control eyes in the expression of angiotensin-converting enzyme 2 and transmembrane protease serine type 2 in the conjunctival epithelium, corneal epithelium, and ciliary muscle. In ocular hypertension eyes and control eyes, angiotensin-converting enzyme 2 and transmembrane protease serine type 2 expression were both observed in the retina. Angiotensin-converting enzyme 2 staining of retinal ganglion cells was found to be significantly higher in ocular hypertension eyes than in control eyes. However, there was no difference in angiotensin-converting enzyme 2 and transmembrane protease serine type 2 expression in retinal vessels and choroidal vessels between ocular hypertension and control eyes. In our study, the expression and distribution of angiotensin-converting enzyme 2 and TMPREE2 in human retina were similar to that of non-human primates as expected. CONCLUSION: Our study confirmed that angiotensin-converting enzyme 2 and transmembrane protease serine type 2 were expressed widely in rhesus monkey eyes. When compared with controls eyes, the expression of angiotensin-converting enzyme 2 was higher in the retinal ganglion cells in ocular hypertension eyes, suggesting that high ocular pressure may affect the patients' ocular susceptibility to severe acute respiratory syndrome coronavirus 2 infection.

Development and Validation of an Internet-Based Remote Perimeter (Perimouse).

Purpose: We sought to validate the feasibility of Perimouse, an internet-based remote perimeter that allows for natural fixation and can be performed on most computers via a web page. Methods: In this cross-sectional study, Perimouse evaluated the visual field of 45 healthy people and 27 patients with primary open-angle glaucoma on a laptop. Participants used a mouse cursor to locate new dots on the screen that were determined by preset saccade vectors. A "click and confirm" strategy was used to eliminate the unwanted visual search. Dot brightness was either fixed at 12 dB in the suprathreshold program (screening program) or variable in the threshold program. We compared Perimouse outcomes with the Humphrey Field Analyzer (HFA) 24-2 Swedish Interactive Testing Algorithm standard program. Results: In the screening program, Perimouse showed moderate to high concordance with HFA. The intraclass coefficient ranged from 0.58 to 0.86 in different areas of Garway-Heath mapping. In the threshold program, normal subjects had threshold ranging from 19 to 16 dB, presenting sensitivity changes according to the "hill of vision". The test-retest difference was 0.09 dB. Habitual spectacle correction and environmental luminance (2-337 lux) had little impact on the central or peripheral threshold (P > 0.05). The correlation between Perimouse and HFA threshold sensitivity was strong (R = 0.950), although Perimouse mean defect was 4.40 dB higher than the HFA mean defect. Conclusions: Perimouse is a reliable visual field test that correlates strongly with HFA. It shows potential for population screening and monitoring visual field defects. Translational Relevance: Perimouse assesses the visual field using saccade vectors without eye trackers, enhancing its accessibility via a web page.

Continuous 24-hour intraocular pressure monitoring in normal Chinese adults using a novel contact lens sensor system.

AIMS: To investigate the physiological nyctohemeral intraocular pressure (IOP) rhythms of normal Chinese adults using a novel contact lens sensor system (CLS) that can output IOP in millimetres of mercury (mm Hg) continuously. METHODS: Fifty-nine eyes of 59 normal Chinese adults completed 24-hour IOP monitoring using the novel CLS. A descriptive analysis was conducted on the 24-hour IOP mean, peak and acrophase, trough and bathyphase, fluctuation, and mean amplitude of intraocular pressure excursion (MAPE). The continuous data were analysed at several periods (diurnal period, 08:00-20:00 hours; nocturnal period, 22:00-06:00 hours; sleep time, 0:00-06:00 hours), and compared between right and left eyes, males and females, and different age ranges (<30, and ≥30), respectively. RESULTS: Normal adults had a lower peak, higher trough, smaller fluctuation and smaller MAPE (p<0.05 for all comparisons) but non-significantly different mean (p=0.695) in the nocturnal period or sleep time compared with the diurnal period. The 24-hour IOP peak and trough showed the frequency of occurrence ranging from 1.69% to 15.25% at an interval of 2 hours. No IOP parameter showed significant difference between right and left eyes (p>0.1 for all comparisons). The male group had larger 24-hour and diurnal IOP fluctuation and MAPE (p<0.05 for all comparisons). Subjects aged 30 or over had higher 24-hour and diurnal mean, higher peak, and larger MAPE (p<0.05 for all comparisons). CONCLUSION: Continuous 24-hour IOP output from the CLS in normal Chinese was stable with a comparable mean level between day and night, as well as scattered acrophase and bathyphase. The 24-hour IOP mean increased with age, and IOP variations were positively correlated to age and male sex.

Clinical features of patients with mutations in genes for nanophthalmos.

BACKGROUND/AIMS: To distinguish the clinical feature of nanophthalmos (NNO) caused by mutations in protease serine 56 (PRSS56), membrane-type frizzled-related protein (MFRP), myelin regulatory factor (MYRF) and transmembrane protein 98 (TMEM98) and to evaluate the association between angle-closure glaucoma (ACG) and NNO. METHODS: Variants in those four genes were identified through exome sequencing/whole genome sequencing data, and bioinformatic analysis was conducted to identify pathogenic/likely pathogenic (P/LP) variants. This observational study comprehensively summarised ophthalmological data of 67 patients with NNO from 63 families. Ocular parameters from 68 eyes without surgical treatment were subjected to further analysis. RESULTS: Totally, 67 patients from 63 families harboured 57 P/LP variants in the four genes, including 30 in PRSS56 (47.6%), 23 in MFRP (36.5%), 5 in TMEM98 (7.9%) and 5 in MYRF (7.9%). ACG was present in 79.1% of patients. An analysis of ocular parameters from 68 eyes revealed that shorter axial length (AL), lower vitreous-to-AL ratios and severe foveal hypoplasia were associated with variants in PRSS56 and MFRP. Uveal effusion was more common in patients with PRSS56 variants, while retinitis pigmentosa was frequently observed in patients with MFRP variants. Patients with MYRF variants exhibited the thinnest retinal nerve fibre layer thickness. Patients with TMEM98 variants had an earlier average onset age of glaucoma. CONCLUSION: Variants in PRSS56 and MFRP are the most common genetic cause of NNO. ACG is a severe complication frequently observed in these patients. Earlier onset of ACG is observed in patients with dominant NNO, while foveal hypoplasia is more common in patients with recessive disease. Recognising these features is helpful in clinical care and genetic counselling.

Pirfenidone inhibits migration, differentiation, and proliferation of human retinal pigment epithelial cells in vitro.

PURPOSE: To investigate the effects of pirfenidone (PFD) on the migration, differentiation, and proliferation of retinal pigment epithelial (RPE) cells and demonstrate whether the drug induces cytotoxicity. METHODS: Human RPE cells (line D407) were treated with various concentrations of PFD. Cell migration was measured with scratch assay. The protein levels of fibronectin (FN), connective tissue growth factor (CTGF), α-smooth muscle actin (α-SMA), transforming growth factor beta (TGFßS), and Smads were assessed with western blot analyses. Levels of mRNA of TGFßS, FN, and Snail1 were analyzed using reverse transcriptase-polymerase chain reaction. Cell apoptosis was detected with flow cytometry using the Annexin V/PI apoptosis kit, and the percentages of cells labeled in different apoptotic stage were compared. A Trypan Blue assay was used to assess cell viability. RESULTS: PFD inhibited RPE cell migration. Western blot analyses showed that PFD inhibited the expression of FN, α-SMA, CTGF, TGFß1, TGFß2, Smad2/3, and Smad4. Similarly, PFD also downregulated mRNA levels of Snail1, FN, TGFß1, and TGFß2. No significant differences in cell apoptosis or viability were observed between the control and PFD-treated groups. CONCLUSIONS: PFD inhibited RPE cell migration, differentiation, and proliferation in vitro and caused no significant cytotoxicity.

Quantitative measurement of interocular suppression in anisometropic amblyopia: a case-control study.

OBJECTIVE: The aims of this study were to assess (1) the relationship between interocular suppression and visual function in patients with anisometropic amblyopia, (2) whether suppression can be simulated in matched controls using monocular defocus or neutral density filters, (3) the effects of spectacle or rigid gas-permeable contact lens correction on suppression in patients with anisometropic amblyopia, and (4) the relationship between interocular suppression and outcomes of occlusion therapy. DESIGN: Case-control study (aims 1-3) and cohort study (aim 4). PARTICIPANTS: Forty-five participants with anisometropic amblyopia and 45 matched controls (mean age, 8.8 years for both groups). METHODS: Interocular suppression was assessed using Bagolini striated lenses, neutral density filters, and an objective psychophysical technique that measures the amount of contrast imbalance between the 2 eyes that is required to overcome suppression (dichoptic motion coherence thresholds). Visual acuity was assessed using a logarithm minimum angle of resolution tumbling E chart and stereopsis using the Randot preschool test. MAIN OUTCOME MEASURES: Interocular suppression assessed using dichoptic motion coherence thresholds. RESULTS: Patients exhibited significantly stronger suppression than controls, and stronger suppression was correlated significantly with poorer visual acuity in amblyopic eyes. Reducing monocular acuity in controls to match that of cases using neutral density filters (luminance reduction) resulted in levels of interocular suppression comparable with that in patients. This was not the case for monocular defocus (optical blur). Rigid gas-permeable contact lens correction resulted in less suppression than spectacle correction, and stronger suppression was associated with poorer outcomes after occlusion therapy. CONCLUSIONS: Interocular suppression plays a key role in the visual deficits associated with anisometropic amblyopia and can be simulated in controls by inducing a luminance difference between the eyes. Accurate quantification of suppression using the dichoptic motion coherence threshold technique may provide useful information for the management and treatment of anisometropic amblyopia. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

How best to assess suppression in patients with high anisometropia.

PURPOSE: We have recently described a rapid technique for measuring suppression using a dichoptic signal/noise task. Here, we report a modification of this technique that allows for accurate measurements to be made in amblyopic patients with high levels of anisometropia. This was necessary because aniseikonic image size differences between the two eyes can provide a cue for signal/noise segregation and, therefore, influence suppression measurement in these patients. METHODS: Suppression was measured using our original technique and with a modified technique whereby the size of the signal and noise elements was randomized across the stimulus to eliminate size differences as a cue for task performance. Eleven patients with anisometropic amblyopia, five with more than 5 diopters (D) spherical equivalent difference (SED), six with less than 5 D SED between the eyes, and 10 control observers completed suppression measurements using both techniques. RESULTS: Suppression measurements in controls and patients with less than 5 D SED were constant across the two techniques; however, patients with more than 5 D SED showed significantly stronger suppression on the modified technique with randomized element size. Measurements made with the modified technique correlated with the loss of visual acuity in the amblyopic eye and were in good agreement with previous reports using detailed psychophysical measurements. CONCLUSIONS: The signal/noise technique for measuring suppression can be applied to patients with high levels of anisometropia and aniseikonia if element size is randomized. In addition, deeper suppression is associated with a greater loss of visual acuity in patients with anisometropic amblyopia.

Reduced interocular suppression after inverse patching in anisometropic amblyopia.

Purpose: Recent investigations observed substantial enhancements in binocular balance, visual acuity, and stereovision among older children and adults with amblyopia by patching the amblyopic eye (i.e., inverse patching) for 2 h daily over 2 months. Despite these promising findings, the precise neural mechanisms underlying inverse patching remain elusive. This study endeavors to delve deeper into the neural alterations induced by inverse patching, focusing on steady-state visual evoked potentials (SSVEPs). We specifically investigate the changes in SSVEPs following monocular deprivation of either the fellow eye or the amblyopic eye in older amblyopic children and adults. Method: Ten participants (17.60 ± 2.03 years old; mean ± SEM), clinically diagnosed with anisometropic amblyopia, were recruited for this study. Each participant underwent a 120 min patching session on their fellow eye on the first day, followed by a similar session on their amblyopic eye on the second day. Baseline steady-state visual evoked potentials (SSVEPs) measurements were collected each day prior to patching, with post-patching SSVEPs measurements obtained immediately after the patching session. The experimental design incorporated a binocular rivalry paradigm, utilizing SSVEPs measurements. Results: The results revealed that inverse patching induced a heightened influence on neural plasticity, manifesting in a reduction of interocular suppression from the fellow eye to the amblyopic eye. In contrast, patching the fellow eye demonstrated negligible effects on the visual cortex. Furthermore, alterations in interocular suppression subsequent to inverse patching exhibited a correlation with the visual acuity of the amblyopic eye. Conclusion: Inverse patching emerges as a promising therapeutic avenue for adolescents and adults grappling with severe anisometropic amblyopia that proves refractory to conventional interventions. This innovative approach exhibits the potential to induce more robust neural plasticity within the visual cortex, thereby modulating neural interactions more effectively than traditional amblyopia treatments.

Targeted reaching with monocular depth information and haptic feedback: Comparing between monocular patients and normally sighted observers.

Monocular blindness impairs visual depth perception, yet patients seldom report difficulties in targeted actions like reaching, walking, or driving. We hypothesized that by utilizing monocular depth information and calibrating actions with haptic feedback, monocular patients can perceive egocentric distance and perform targeted actions. We compared targeted reaching in monocular patients, monocular-viewing, and binocular-viewing normal controls. Sixty observers reached either a far or a near target, calibrating reaches to the near target with accurate or false feedback while leaving reaches to the far target uncalibrated. Reaching accuracy and precision were analyzed. Results indicated no difference in reaching accuracy between monocular patients and normal controls; all groups initially underestimated distances before until calibration. Monocular patients responded to calibration sensitively, achieving accuracy in calibrated reaches and generalizing this effect to uncalibrated distances. Thus, with monocular depth information and haptic feedback, monocular patients could perceive distance and accomplish targeted reaching.

Inhibition of TGF-ß2-Induced Trabecular Meshwork Fibrosis by Pirfenidone.

Purpose: Trabecular meshwork (TM) fibrosis is a crucial pathophysiological process in the development of primary open-angle glaucoma. Pirfenidone (PFD) is a new, broad-spectrum antifibrotic agent approved for the treatment of idiopathic pulmonary fibrosis. This study investigated the inhibitory effect of PFD on TM fibrosis and evaluated its efficacy in lowering intraocular pressure (IOP). Methods: Human TM cells were isolated, cultured, and characterized. Cell Counting Kit-8 was used to evaluate the proliferation and toxicity of different concentrations of PFD on normal or fibrotic TM cells. TM cells were treated with transforming growth factor beta-2 (TGF-ß2) in the absence or presence of PFD. Western blotting and immunofluorescence analyses were used to analyze changes in the TM cell cytoskeleton and extracellular matrix (ECM) proteins, including alpha-smooth muscle actin (α-SMA), F-actin, collagen IV (COL IV), and fibronectin (FN). An ocular hypertension (OHT) mouse model was induced with Ad-TGF-ß2C226/228S and then treated with PFD or latanoprost (LT) eye drops to confirm the efficacy of PFD in lowering IOP. Results: PFD inhibited the proliferation of fibrotic TM cells in a dose-dependent manner and inhibited TGF-ß2-induced overexpression of α-SMA, COL IV, and FN in TM cells. PFD stabilized F-actin. In vivo, PFD eye drops reduced the IOP of the OHT models and showed no significant difference compared with LT eye drops. Conclusions: PFD inhibited TGF-ß2-induced TM cell fibrosis by rearranging the disordered cytoskeleton and decreasing ECM deposition, thereby enhancing the aqueous outflow from the TM outflow pathway and lowering IOP, which provides a potential new approach to treating glaucoma. Translational Relevance: Our work with pirfenidone provides a new approach to treat glaucoma.

Monocular information for perceiving large egocentric distance: A comparison between monocularly blind patients and normally sighted observers.

The debate surrounding the advantages of binocular versus monocular vision has persisted for decades. This study aimed to investigate whether individuals with monocular vision loss could accurately and precisely perceive large egocentric distances in real-world environments, under natural viewing conditions, comparable to those with normal vision. A total of 49 participants took part in the study, divided into three groups based on their viewing conditions. Two experiments were conducted to assess the accuracy and precision of estimating egocentric distances to visual targets and the coordination of actions during blind walking. In Experiment 1, participants were positioned in both a hallway and a large open field, tasked with judging the midpoint of self-to-target distances spanning from 5 to 30 m. Experiment 2 involved a blind walking task, where participants attempted to walk towards the same targets without visual or environmental feedback at an unusually rapid pace. The findings revealed that perceptual accuracy and precision were primarily influenced by the environmental context, motion condition, and target distance, rather than the visual conditions. Surprisingly, individuals with monocular vision loss demonstrated comparable accuracy and precision in perceiving egocentric distances to that of individuals with normal vision.