Outcomes of initial and repeat micro-pulse transscleral cyclophotocoagulation in adult glaucoma patients

BACKGROUND

Micro-pulse transscleral cyclophotocoagulation (MP-TSCPC) has continued to gain popularity as a treatment in adult glaucoma patients. Thus far there is limited evidence reporting the efficaciousness and safety of retreatment.

OBJECTIVE

To evaluate safety and efficacy of primary and repeat MP-TSCPC procedures.

METHODS

Thirty-four of 67 eyes who failed to achieve target IOP from initial MP-TSCPC underwent repeat MP-TSCPC and followed for a minimum of 6 months. All treatments were performed using the laser power of 2000 or 2250 mW, duration of 100-200 s, and a velocity 16-20 s per hemisphere swipe. Success criteria were defined as intraocular pressure (IOP) reduction of greater than 20% from baseline or any medication reduction without additional glaucoma procedures at 6 months after repeat MP-TSCPC. The 6-month success rate after repeat MP-TSCPC was also compared to that of initial MP-TSCPC in the same group of eyes.

RESULTS

Mean baseline IOP before the repeat MP-TSCPC was 23.0 + /- 5.3 on 3.0 + /- 1.4 medications. At 6 months, mean post-op IOP was 18.2 + /- 5.4 (21.9% reduction, p < 0.002), with mean medication staying relatively the same (p = .976). Success rate was increased from 23.5% to 44.1% with the repeat procedure compared to that of initial procedure (p = 0.123). Mean IOP reduction was also greater after repeat MP-TSCPC (18.7%, p < 0.002) when compared to initial MP-TSCPC (10.4%). No adverse events occurred.

CONCLUSIONS

MP-TSCPC is a safe and effective non-invasive means to lower IOP in a variety of glaucoma patients. While over 50% (34/67) of eyes required repeat MP-TSCPC, repeat treatment resulted in greater success rates and IOP reduction without any adverse events when using the total energy between 112 and 150 J.

Gravitational effects on intraocular pressure and ocular perfusion pressure

Changes in the gravitational vector by postural changes or weightlessness induce fluid shifts, impacting ocular hemodynamics and regional pressures. This investigation explores the impact of changes in the direction of the gravitational vector on intraocular pressure (IOP), mean arterial pressure at eye level (MAP_eye), and ocular perfusion pressure (OPP), which is critical for ocular health. Thirteen subjects underwent 360° of tilt (including both prone and supine positions) at 15° increments. At each angle, steady-state IOP and MAP_eye were measured, and OPP calculated as MAP_eye - IOP. Experimental data were also compared to a six-compartment lumped-parameter model of the eye. Mean IOP, MAP_eye, and OPP significantly increased from 0° supine to 90° head-down tilt (HDT) by 20.7 ± 1.7 mmHg (P < 0.001), 38.5 ± 4.1 mmHg (P < 0.001), and 17.4 ± 3.2 mmHg (P < 0.001), respectively. Head-up tilt (HUT) significantly decreased OPP by 16.5 ± 2.5 mmHg (P < 0.001). IOP was significantly higher in prone versus supine position for much of the tilt range. Our study indicates that OPP is highly gravitationally dependent. Specifically, data show that MAP_eye is more gravitationally dependent than IOP, thus causing OPP to increase during HDT and to decrease during HUT. In addition, IOP was elevated in prone position compared with supine position due to the additional hydrostatic column between the base of the rostral globe to the mid-coronal plane, supporting the notion that hydrostatic forces play an important role in ocular hemodynamics. Changes in OPP as a function of changes in gravitational stress and/or weightlessness may play a role in the pathogenesis of spaceflight-associated neuro-ocular syndrome.NEW & NOTEWORTHY Maintaining appropriate ocular perfusion pressure (OPP) is critical for ocular health. We measured the relative changes in intraocular and mean arterial pressures during 360° tilt and calculated OPP, which was elevated during head-down tilt and decreased during head-up tilt. Experimental data are also explained by our computational model. We demonstrate that OPP is more gravitationally dependent than previously recognized and may be a factor in the overall patho-etiology behind the weightlessness-induced spaceflight-associated neuro-ocular syndrome.

A prospective study on effectiveness of elevated intraocular pressure as a criterion for glaucoma referrals by optometric practitioners in Sweden

PURPOSE

To evaluate the outcome of referrals for suspected glaucoma based on elevated intraocular pressure (IOP) made by optometric practitioners in Sweden.

METHODS

This prospective study included 95 individuals referred to the Skåne University Hospital Malmö, Sweden, during 2019, by optometric practitioners, based on elevated IOP. Positive outcome was defined as a diagnosis of glaucoma, or a diagnosis of suspected glaucoma. Referral accuracy was analysed. Positive predictive values (PPV) of different hypothetical IOP and age thresholds were calculated.

RESULTS

In 34% (95% CI: 24-43%) of the referrals, no eye disease was found. Intraocular pressure (IOP) was the only referral criterion in 77% (73/95). The PPV was 35% (95% CI: 25-45%) for all referrals, 27% (95% CI: 16-38%) for IOP-only referrals and 59% (95% CI: 36-82%) for referrals including additional findings. In IOP-only referrals, no definite diagnosis of glaucoma was made in any patients <45 years of age. Applying a theoretical age limit of ≥45 years with a hypothetical IOP limit of ≥25 mmHg in patients 45-69 years and of ≥22 mmHg in patients ≥70 years increased the PPV to 42% (95% CI: 27-57%). IOP-only referrals would have been reduced by 27% without missing any glaucoma cases.

CONCLUSION

The overall predictive value of the referrals was poor. Glaucoma resources would have been used more effectively by increasing the required age for IOP-only referrals to ≥45 years in combination with different IOP thresholds for certain age groups.

Strain by virtual extensometers and video-imaging optical coherence tomography as a repeatable metric for IOP-Induced optic nerve head deformations

PURPOSE

To determine if in vivo strain response of the Optic Nerve Head (ONH) to IOP elevation visualized using Optical Coherence Tomography (OCT) video imaging and quantified using novel virtual extensometers was able to be provided repeatable measurements of tissue specific deformations.

METHODS

The ONHs of 5 eyes from 5 non-human primates (NHPs) were imaged by Spectralis OCT. A vertical and a horizontal B-scan of the ONH were continuously recorded for 60 s at 6 Hz (video imaging mode) during IOP elevation from 10 to 30 mmHg. Imaging was repeated over three imaging sessions. The 2D normal strain was computed by template-matching digital image correlation using virtual extensometers. ANOVA F-test (F) was used to compare inter-eye, inter-session, and inter-tissue variability for the prelaminar, Bruch's membrane opening (BMO), lamina cribrosa (LC) and choroidal regions (against variance the error term). F-test of the ratio between inter-eye to inter-session variability was used to test for strain repeatability across imaging sessions (FIS).

RESULTS

Variability of strain across imaging session (F = 0.7263, p = 0.4855) and scan orientation was not significant (F = 1.053, p = 0.3066). Inter session variability of strain was significantly lower than inter-eye variability (FIS = 22.63, p = 0.0428) and inter-tissue variability (FIS = 99.33 p = 0.00998). After IOP elevation, strain was highest in the choroid (-18.11%, p < 0.001), followed by prelaminar tissue (-11.0%, p < 0.001), LC (-3.79%, p < 0.001), and relative change in BMO diameter (-0.57%, p = 0.704).

CONCLUSIONS

Virtual extensometers applied to video-OCT were sensitive to the eye-specific and tissue-specific mechanical response of the ONH to IOP and were repeatable across imaging sessions.

Immune responses to injury and their links to eye disease

The eye is regarded as an immune privileged site. Since the presence of a vasculature would impair vision, the vasculature of the eye is located outside of the central light path. As a result, many regions of the eye evolved mechanisms to deliver immune cells to sites of dysgenesis, injury, or in response to the many age-related pathologies. While the purpose of these immune responses is reparative or protective, cytokines released by immune cells compromise visual acuity by inducing inflammation and fibrosis. The response to traumatic or pathological injury is distinct in different regions of the eye. Age-related diseases impact both the anterior and posterior segment and lead to reduced quality of life and blindness. Here we focus attention on the role that inflammation and fibrosis play in the progression of age-related pathologies of the cornea and the lens as well as in glaucoma, the formation of epiretinal membranes, and in proliferative vitreoretinopathy.

Incidence of presumed steroid response in contralateral eye of patients who underwent glaucoma filtration surgery

PURPOSE

The aim of this study was to report the incidence of presumed steroid response in contralateral eye of patients who underwent glaucoma filtration surgery.

METHODS

We reviewed records of 298 glaucoma patients (147 PACG [primary angle-closure glaucoma], 129 POAG [primary open-angle glaucoma], and 22 JOAG [juvenile open-angle glaucoma]) who underwent either trabeculectomy alone or trabeculectomy with cataract extraction. All patients received prednisolone acetate 1% eye drop postoperatively in the operated eye for up to 6 to 8 weeks. The contralateral eye received the same antiglaucoma medications as before. Information collected included age, sex, number of antiglaucoma medications in the fellow eye preoperatively, and VFI (visual field index). The preoperative intraocular pressure (IOP) in the contralateral eye was taken as the baseline. The maximum IOP recorded postoperatively up to a follow-up period of 6 to 8 weeks was noted. A steroid response was defined as rise in the IOP by ≥6 mmHg.

RESULTS

In this study, 298 eyes of 298 glaucoma patients were included. The mean age of patients was 60.1 ± 13.7 years. The mean number of antiglaucoma medications in the fellow eye pre-operatively was 2.4 ± 1.2. Mean preoperative and postoperative IOP in the fellow eye were 17.46 ± 7 and 19.37 ± 7.1 mmHg, respectively. Sixty-three eyes out of 298 eyes (21.14%) showed a rise in IOP by 6 mmHg. The maximum IOP difference noted was 15 mmHg. The average time interval to the defined steroid response was 16.13 days. The majority showed a steroid response within 19 days.

CONCLUSION

Steroid response is a significant factor leading to elevated IOP postoperatively in the contralateral eye as well.

Comparison of Viscoelastic Substance Injection Versus Air Filling in the Anterior Chamber During Foldable Capsular Vitreous Body (FCVB) Implant Surgery: A Prospective Randomized Controlled Trial

INTRODUCTION

To compare the outcomes of viscoelastic substance injection with air filling in the anterior chamber during foldable capsular vitreous body (FCVB) implant surgery in patients with severe retinal disease.

METHODS

Thirty eyes with severe retinal diseases were randomly divided into two groups. In the viscoelastic group, 0.15-0.2 mL of 1.7% sodium hyaluronate was injected into the anterior chamber after FCVB implantation; in the air group, the anterior chamber was maintained by filling the air after FCVB implant surgery. The eyes of treated patients were examined during a 24-week follow-up appointment. Data, including intraocular pressure (IOP), the difference between preoperative and postoperative IOP, and postoperative complications, were recorded.

RESULTS

Data collected from 27 eyes were used in the final analysis. The IOP of the air group was lower than that of the viscoelastic group from the first to third postoperative day (P < 0.01). Moreover, the difference between preoperative and postoperative IOP in the viscoelastic group was significantly smaller than that in the air group from the first to third postoperative day (P < 0.01). After the 1st postoperative week, postoperative IOP values were similar in the two groups (P > 0.05). Postoperative complications in the air group and the viscoelastic group included corneal blood staining (1 eye vs. 0 eyes), transient postoperative diffuse hemorrhage (5 eyes vs. 1 eye), inflammation reaction (9 eyes vs. 4 eyes), and postoperative fibrin exudation (4 eyes vs. 1 eye), respectively.

CONCLUSION

The use of viscoelastic substances in the anterior chamber during FCVB implant surgery was associated with less fluctuation in postoperative IOP and could reduce postoperative complications.

REGISTRATION NUMBER

ChiCTR-TNC-00000396.

Effects of acute stress, general anesthetics, tonometry, and temperature on intraocular pressure in rats

Intraocular pressure (IOP) is important for eye health as abnormal levels can led to ocular tissue damage. IOP is typically estimated by tonometry, which only provides snapshots of pressure history. Tonometry also requires subject cooperation and corneal contact that may influence IOP readings. The aim of this research was to investigate IOP dynamics of conscious animals in response to stressors, common anesthetics, tonometry, and temperature manipulations. An eye of male Brown-Norway rats was implanted with a fluid-filled cannula connected to a wireless telemetry system that records IOP continuously. Stress effects were examined by restricting animal movements. Anesthetic effects were examined by varying isoflurane concentration or injecting a bolus of ketamine. Tonometry effects were examined using applanation and rebound tonometers. Temperature effects were examined by exposing anesthetized and conscious animals to warm or cool surfaces. Telemetry recordings revealed that IOP fluctuates spontaneously by several mmHg, even in idle and anesthetized animals. Environmental disturbances also caused transient IOP fluctuations that were synchronous in recorded animals and could last over a half hour. Animal immobilization produced a rapid sustained elevation of IOP that was blocked by anesthetics, whereas little-to-no IOP change was detected in isoflurane- or ketamine-anesthetized animals if body temperature (BT) was maintained. IOP and BT decreased precipitously when heat support was not provided and were highly correlated during surface temperature manipulations. Surface temperature had no impact on IOP of conscious animals. IOP increased slightly during applanation tonometry but not rebound tonometry. The results show that IOP is dynamically modulated by internal and external factors that can activate rapidly and last long beyond the initiating event. Wireless telemetry indicates that animal interaction induces startle and stress responses that raise IOP. Anesthesia blocks these responses, which allows for better tonometry estimates of resting IOP provided that BT is controlled.

Potential effects of angiogenesis-related factors on the severity of APAC and surgical outcomes of trabeculectomy

Background

EPO (erythropoietin) and PDGF (platelet derived growth factor) families are thought to be associated with angiogenesis under hypoxic condition. The sharp rise of intraocular pressure in acute primary angle closure (APAC) results in an inefficient supply of oxygen and nutrients. We aimed to measure the expression of EPO and PDGF family members in APAC eyes and demonstrate their associations with APAC’s surgical success rate.

Methods

Concentrations of EPO, PDGF-AA, -BB, -CC and -DD collected in aqueous humor samples of 55 patients recruited were measured. Before operations, correlations between target proteins and IOP (intraocular pressure) were detected between APAC (acute primary angle closure) and cataract patients. Based on the post-operative follow-up, the effects of EPO and PDGF family members on the successful rate of trabeculectomy were tested.

Results

The levels of EPO, PDGF-CC and -DD were significantly elevated in the APAC group compared to the cataract group. During the post-operative follow-up, EPO, PDGF-CC and -DD showed significant differences between the success and failure groups. In multivariable linear regression analyses, failed filtration surgery was more likely in APAC eyes with higher EPO level. The Kaplan-Meier survival plot suggested that the success rate in eyes with low EPO level was significantly higher than that in eyes with high EPO level.

Conclusion

The levels of EPO, PDGF-CC and -DD were significantly elevated in failure group. EPO level correlated with preoperative IOP and numbers of eyedrops, and higher EPO level in aqueous humor is a risk factor for trabeculectomy failure. It can be a biomarker to estimate the severity of APAC and the success rate of surgery. The investigation of mechanism of EPO in APAC a may have potential clinical applications for the surgical treatment of APAC.

Treatment Success Across Different Levels of Preoperative Disease Burden: Stratified Two-Year Outcomes from the Pivotal Trial of iStent inject ® Trabecular Micro-Bypass in Primary Open-Angle Glaucoma and Cataract

PURPOSE

To examine effectiveness outcomes stratified by preoperative disease burden in the pivotal trial of iStent inject ® with cataract surgery (INJ) vs cataract surgery alone (CS).

MATERIALS AND METHODS

Prospective, 3:1 randomized, single-masked, concurrently-controlled, multicenter trial enrolling 505 subjects with cataract and mild-to-moderate primary open-angle glaucoma who underwent iStent inject implantation with phacoemulsification or phacoemulsification alone, and were followed for 2 years including annual medication washouts. Post hoc stratification was completed for baseline mean diurnal intraocular pressure (BL DIOP; Low-DIOP <25mmHg, Mid-DIOP ≥25 to <30 mmHg, High-DIOP ≥30mmHg) and preoperative medication burden (Low-Med 1 medication, Mid-Med 2 medications, High-Med ≥3 medications).

RESULTS

The 24-month primary and secondary effectiveness endpoints were met, with significant treatment-over-control differences in percent of eyes achieving ≥20% unmedicated DIOP reduction and in unmedicated DIOP reduction, respectively. In subgroup analyses, the proportions of INJ eyes achieving the primary endpoint remained steady across all BL DIOP (75.4%, 77.1%, 74.4% in Low/Mid/High-DIOP strata, respectively) and preoperative medication levels (76.8%, 70.8%, 79.7% in Low/Mid/High-Med strata, respectively); meanwhile, the proportions of CS eyes diminished with higher BL DIOP (64.5%, 63.6%, 33.3%, respectively) and more medications (69.0%, 63.3%, 29.4%, respectively). Regarding secondary effectiveness, postoperative DIOP reduction increased with higher BL DIOP in INJ eyes (6.2mmHg, 7.8mmHg, 9.8mmHg, respectively) but plateaued in CS eyes (5.2mmHg, 5.8mmHg, 5.4mmHg, respectively). INJ eyes also had consistent DIOP reduction regardless of preoperative medication burden (6.8mmHg, 6.7mmHg, 7.8mmHg, respectively), while DIOP reduction diminished with more medications in CS eyes (6.1mmHg, 5.0mmHg, 3.3mmHg, respectively). Safety was favorable, comparable to phacoemulsification alone.

CONCLUSION

Significant IOP reductions occurred across all levels of BL DIOP and preoperative medication burden in iStent inject eyes. DIOP reductions increased with higher BL DIOP and remained stable across all levels of preoperative medication burden, suggesting the device's potential utility in more medically challenging cases.

Surface Engineering of FLT4-Targeted Nanocarriers Enhances Cell-Softening Glaucoma Therapy

Primary open-angle glaucoma is associated with elevated intraocular pressure (IOP) that damages the optic nerve and leads to gradual vision loss. Several agents that reduce the stiffness of pressure-regulating Schlemm's canal (SC) endothelial cells, in the conventional outflow pathway of the eye, lower IOP in glaucoma patients and are approved for clinical use. However, poor drug penetration and uncontrolled biodistribution limit their efficacy and produce local adverse effects. Compared to other ocular endothelia, FLT4/VEGFR3 is expressed at elevated levels by SC endothelial cells and can be exploited for targeted drug delivery. Here, we validate FLT4 receptors as clinically relevant targets on SC cells from glaucomatous human donors and engineer polymeric self-assembled nanocarriers displaying lipid-anchored targeting ligands that optimally engage this receptor. Targeting constructs were synthesized as lipid-PEGx-peptide, differing in the number of PEG spacer units (x), and were embedded in micelles. We present a novel proteolysis assay for quantifying ligand accessibility that we employ to design and optimize our FLT4-targeting strategy for glaucoma nanotherapy. Peptide accessibility to proteases correlated with receptor-mediated targeting enhancements. Increasing the accessibility of FLT4-binding peptides enhanced nanocarrier uptake by SC cells while simultaneously decreasing the uptake by off-target vascular endothelial cells. Using a paired longitudinal IOP study in vivo, we show that this enhanced targeting of SC cells translates to IOP reductions that are sustained for a significantly longer time as compared to controls. Confocal microscopy of murine anterior segment tissue confirmed nanocarrier localization to SC within 1 h after intracameral administration. This work demonstrates that steric effects between surface-displayed ligands and PEG coronas significantly impact the targeting performance of synthetic nanocarriers across multiple biological scales. Minimizing the obstruction of modular targeting ligands by PEG measurably improved the efficacy of glaucoma nanotherapy and is an important consideration for engineering PEGylated nanocarriers for targeted drug delivery.

Pharmacological Profile and Ocular Hypotensive Effects of Cromakalim Prodrug 1, a Novel ATP-Sensitive Potassium Channel Opener, in Normotensive Dogs and Nonhuman Primates

Purpose: To evaluate pharmacokinetic parameters and ocular hypotensive effects of cromakalim prodrug 1 (CKLP1) in normotensive large animal models. Methods: Optimal CKLP1 concentration was determined by dose response and utilized in short- (5-8 days) and long-term (60 days) evaluation in hound dogs (n = 5) and African Green Monkeys (n = 5). Blood pressure was recorded 3-5 times per week with a tail cuff. Concentrations of CKLP1 and the parent compound levcromakalim were assessed in hound dog plasma and select tissues by LC-MS/MS after bilateral ocular treatment with CKLP1 for 8 days. Pharmacokinetic parameters were calculated from days 1, 4, and 8 data. After necropsy, histology was assessed in 43 tissue samples from each animal. Results: In hound dogs and African Green monkeys, 10 mM CKLP1 (optimal concentration) significantly lowered intraocular pressure (IOP) by 18.9% ± 1.1% and 16.7% ± 6.7%, respectively, compared with control eyes (P < 0.05). During treatment, no significant change in systolic or diastolic blood pressure was observed in either species (P > 0.1). Average values for half-life of CKLP1 was 295.3 ± 140.4 min, Cmax, 10.5 ± 1.6 ng/mL, and area under the concentration vs. time curve (AUClast) 5261.4 ± 918.9 ng·min/mL. For levcromakalim, average values of half-life were 96.2 ± 27 min, Cmax 1.2 ± 0.2 ng/mL, and AUClast 281.2 ± 110.8 ng·min/mL. No significant pathology was identified. Conclusions: CKLP1 lowered IOP in hound dogs and African green monkeys with no effect on systemic blood pressure. Ocular topical treatment of CKLP1 showed excellent tolerability even after extended treatment periods.

Clinical Study of the IOPTx™ System - an Electroceutical Wearable to Lower Intraocular Pressure

Purpose: To investigate the safety and efficacy of the IOPTx™ system - a novel wearable, electroceutical treatment to lower intraocular pressure. Methods: Patients wear the customized contact lens and spectacles of the IOPTx™ system and undergo three 15-minute randomized stimulation trials at different stimulus amplitudes with 15 minutes of rest in between. The parameters for the stimulation trials include a frequency of 50 Hz, a pulse width of 100 µs, and current amplitudes between 90-150 µA. The optometrist measures the intraocular pressure (IOP) before, immediately after, and 15 minutes after the trial, and performs topography, a slit eye examination, and specular microscopy before and after the entire study to check the health of the eye and confirm the safety of the system. Results: The IOPTx™ system successfully modulates a patient's IOP. By testing various currents, we create individual tuning curves examining the effect of the stimulation amplitude on the change in IOP. Each patient may have an optimal dose-response curve and by normalizing to this value, the IOPTx™ system decreased IOP by an average of 17.7% with fifteen minutes of therapy. No Adverse Events or Adverse Device Effects occurred.Conclusions: The results of this clinical case series provide preliminary evidence of efficacy and safety of the IOPTx™ system and its potential usefulness to lower IOP in glaucoma and ocular hypertension.

Effect of general inhalational anesthesia on intraocular pressure measurements in normal and glaucomatous children

PURPOSE

To investigate the agreement between the intraocular pressure (IOP) measurements in the awake condition and under different stages of general inhalational anesthesia using sevoflurane in both glaucomatous and normal children.

METHODS

A prospective study was performed on 43 glaucomatous children and 30 age-matched controls. Baseline IOP of one eye was measured immediately before general anesthesia using Perkins tonometer and then re-measured under light, intermediate, and deep anesthesia, and then after intubation. Depth of anesthesia was determined using bispectral index pediatric sensor. The agreement between the IOP measurements before and during different stages of anesthesia was analyzed using Bland-Altman plots. Systematic and proportionate deviations between the IOP measurements were analyzed.

RESULTS

The mean age was 58.6 ± 41.99 months. The mean IOP was significantly lower at all stages of anesthesia in both groups. The coefficient of variation was over 20% in all measurements under anesthesia. For all IOP measurements during anesthesia, the limits of agreement were > 7 mmHg difference in the control group and > 20 mmHg in the glaucomatous group. The best agreement was with the IOP measurement after intubation (mean limit of agreement of -1.4 mmHg, 1.96 s range, -8.8-6 mm Hg) in the control group and with the IOP measurement under intermediate anesthesia (mean limit of agreement of -4.2 mmHg, 1.96 s range, -15.1-6.8 mm Hg) in the glaucomatous group.

CONCLUSIONS

Inhalational anesthesia has variable effects on IOP measurement at all stages of anesthesia. Caution should be taken when extrapolating the true IOP from these measurements.

Sympathetic context of the disease - a new era in glaucoma management

Primary open angle glaucoma (POAG) is a multifactorial optic neuropathy, which progresses in a chronic manner. Several etiological factors are involved, including genetic factors, race, age, IOP or vascular, systemic factors. IOP has an established role in the initiation and evolution of glaucoma, but its interactions with additional risk factors are complex. We propose the notion of the Glaucoma Etiological Area (GEA), as a representation of all the elements acting in collaboration in the physiopathology of each glaucoma case. When combined in different proportions, these elements may trigger the typical glaucomatous optic neuropathy (GON). We know that the statistical values of IOP are valid for normal eyes, but the glaucoma eye is not a normal eye. The notion of GEA can open a new perspective to interpret IOP values and to assess the true value of IOP control as a treatment for glaucoma. Applying the GEA theory allows us to tune the role of IOP. Additional factors, such as ocular properties (RGCL status, CCT, IOP fluctuation curve), ocular comorbidities (PEX, PDS), systemic comorbidities (arterial hypertension, vasospastic diseases such as migraines or Reynaud’s syndrome) or patient’s attitude towards glaucoma management (treatment compliance, access to follow-up and treatment) may greatly influence the evolution of GON and should be viewed holistically when developing a management plan for each patient. Applying the notion of GEA in clinical practice allows a more realistic approach of the pathophysiology of the disease and for a glaucoma treatment that is tailored to each patient.

Abbreviations: AG = advanced glaucoma, BP = blood pressure, CCT = central corneal thickness, CIGTS = Collaborative Initial Glaucoma Treatment Study, CNTGS = Collaborative Normal-Tension Glaucoma Study, EMGT = Early Manifest Glaucoma Trial, GEA = glaucoma etiological area, GON = glaucomatous optic neuropathy, IOP = intraocular pressure, NTG = Normal Tension Glaucoma, OHTS = Ocular Hypertension Study, PDS = Pigmentary dispersion syndrome, PEX = Pseudoexfoliation syndrome, POAG - primary open-angle glaucoma, RGCL = retinal ganglion cell layer, VFL = visual field loss

Cubogel as potential platform for glaucoma management

The aim of this work is to survey the potential of cubogel as an ocular dosage form to boost the corneal permeability of Dorzolamide Hydrochloride DZ; an antiglaucomal drug. DZ-loaded cubosomal dispersions were prepared according to Box-Behnken design, where the effect of independent variables; Monoolein MO concentration (2.5, 5 and 7.5%w/w), Pluronic^® F127 concentration (0.25, 0.5 and 0.75%w/w) and magnetic stirrer speed of (400, 800 and 1200 rpm) was studied on PS (nm), Zp (−mV) and Q 2 h (%) respectively. The prepared formulae were characterized via drug content DC (%), particle size PS (nm), polydispersity index PDI, zeta potential Zp (−mV), in-vitro drug release (Q 2 h%) and finally TEM. The optimized formulation composed of: 6.13% w/w of MO, 0.75% w/w of F127 and prepared at 1200 rpm stirring speed was chosen based on the criteria of minimum PS (nm), maximum Zp (−mV) and minimum Q 2 h (%). Results revealed that the optimum formula showed PS of 153.3 ± 8.4 n, Zp of 32 ± 3 −mV and 37.78 ± 1.3% released after 2 h. Carbopol 934 (1% w/v) as gelling agent was used to prepare the optimum cubogel, which was further evaluated by DSC, ex-vivo permeation and stability studies at 4 °C for three months. Moreover, in vivo studies of the optimized cubogel include; draize test, histological examination, confocal laser scanning microscopy (CLSM) and intraocular pressure (IOP) measurement. Results revealed that the optimized cubogel was considerably safe, stable and competent to corneal delivery as assured by draize and histological examination. CLSM showed a deeper penetration of more than 2.5-fold. A higher bioavailability (288.24 mg. h/ml) was attained from cubogel compared to the market product Trusopt^® eye drops (115.40 mg. h/ml) following IOP measurement. Therefore, DZ-loaded cubogel could be considered as promising delivery system to boost the transcorneal permeation hence corneal bioavailability of DZ as antiglaucomal drug.

Effects of Scleral Contact Lenses for Keratoconus Management on Visual Quality and Intraocular Pressure

Purpose

To evaluate the visual acuity level achieved by scleral contact lens (CL) fitting in patients affected by keratoconus and to evaluate possible intraocular pressure (IOP) changes during the scleral CL wear using a transpalpebral tonometer.

Methods

In a prospective case series a comparison was made between visual acuity obtained with glasses, RGP and 16.8mm diameter scleral CL in 30 consecutive patients affected by keratoconus. IOP was tested during scleral CL wear by transpalpebral Diaton Tonometer (DT) and also by Goldmann Applanation Tonometer (GAT) before and after scleral CL wear.

Results

The mean logMAR visual acuity improved from 0.2±0.25SD with glasses and 0.1±0.02SD with RGP, to −0.002±0.041SD when using the scleral CL (p<0.05). The mean IOP value before scleral CL wear was 12.93mmHg±2.20SD when measured with GAT and 7.85mmHg±2.27SD when measured with DT. During scleral CL wear, IOP was assessed through DT, with a mean value of 8.86mmHg±2.36SD; values were stable after 8 hours of scleral CL use. Immediately after scleral CL removal, the mean IOP measured with GAT was 12.85mmHg ±2.40SD and the mean IOP measured with DT was 7.66mmHg±1.88SD. Therefore, during scleral CL wear, it was evidenced a small but statistically significant increase of the mean IOP value (1.01mmHg; p<0.01), with a reversion to values prior to application when scleral CL was removed.

Conclusion

Scleral CLs remarkably improved visual acuity in keratoconus patients when compared to glasses or RGP contact lenses. Even if it was evidenced a small increase of the mean IOP value during their wear, it may not be significant in otherwise healthy eyes. Statistical analysis demonstrated good agreement between GAT and DT but their numerical values presented a constant gap, that should be taken into account when there is a need to relate the DT values to the reference ones.

Wearable Contact Lens Sensor for Non-invasive Continuous Monitoring of Intraocular Pressure

Intraocular pressure (IOP) is an essential indicator of the diagnosis and treatment of glaucoma. IOP has an apparent physiological rhythm, and it often reaches its peak value at night. To avoid missing the peak value at night and sample the entire rhythm cycle, the continuous monitoring of IOP is urgently needed. A wearable contact lens IOP sensor based on a platinum (Pt) strain gauge is fabricated by the micro-electro-mechanical (MEMS) process. The structure and parameters of the strain gauge are optimized to improve the sensitivity and temperature stability. Tests on an eyeball model indicate that the IOP sensor has a high sensitivity of 289.5 μV/mmHg and excellent dynamic cycling performance at different speeds of IOP variation. The temperature drift coefficient of the sensor is 33.4 μV/°C. The non-invasive IOP sensor proposed in this report exhibits high sensitivity and satisfactory stability, promising a potential in continuous IOP monitoring.

The treatment of glaucoma using topical preservative-free agents: an evaluation of safety and tolerability

Introduction: Preservative-free (PF) medications represent a valuable treatment strategy in the lifelong management of glaucoma. By removing preservative toxicity, PF formulations provide tangible clinical benefits to glaucoma patients worldwide. They improve tolerability and adherence, leading to a positive impact in long-term intraocular pressure (IOP) control.Areas covered: A critical review of the subject is provided, including selected evidence on the safety and tolerability of currently available topical PF formulations. Cumulative evidence confirms that topical PF medications are at least equally efficacious to their preserved equivalents. There is convincing short-term evidence for superior tolerability and safety of PF formulations compared to preserved medications. The long-term benefits and success of PF therapy requires further elucidation.Expert opinion: Successful stepwise administration of medical therapy for glaucoma remains elusive. There is a greater risk for ocular toxicity and therapy failure with preserved topical glaucoma therapy. Currently available and emerging PF therapy options potentially optimize lifelong stepwise glaucoma therapy and may enhance outcome. To avert complications from preservatives leading to poor adherence, ideally, future antiglaucoma therapy should become 100% PF. There are still key aspects of PF therapy that warrant further investigation.

Pedunculated Lipoma of the Caecum Causing Colocolic Intussusception in an Adult

Introduction

Colocolic intussusception in adults is uncommon and poses both a diagnostic and therapeutic dilemma. The association of an underlying malignancy necessitates a preoperative confirmation of diagnosis. The presenting features are variable. Hence contrast enhanced computed tomography of the abdomen is pivotal for diagnosis. An en bloc resection of the specimen in accordance with standard oncological principles is the mainstay of treatment.

Case report

A case of colocolic intussusception in an adult is presented to highlight the difficulties in preoperative diagnosis and in selecting the best surgical option for treatment.

Conclusion

Adult bowel intussusception is a diagnostic dilemma with preoperative diagnosis being the biggest challenge. CT scan of the abdomen is an excellent diagnostic modality with high diagnostic accuracy. Explorative laparotomy with en bloc resection is mainstay of treatment in adults.

Phentolamine Mesylate Ophthalmic Solution Provides Lasting Pupil Modulation and Improves Near Visual Acuity in Presbyopic Glaucoma Patients in a Randomized Phase 2b Clinical Trial

PURPOSE

Phentolamine mesylate ophthalmic solution (PMOS), applied to the eye topically, was shown previously to have beneficial effects in patients with dim light vision disturbances (DLD), including decreased pupil diameter (PD), improved best-corrected distance visual acuity (BCDVA), as well as lower intraocular pressure (IOP). The ORION-1 trial evaluated the long-term safety and efficacy of PMOS in a glaucomatous, presbyopic population.

PATIENTS AND METHODS

In this randomized, double-masked, multi-center, placebo-controlled, multiple-dose Phase 2b trial, 39 patients with elevated IOP were randomized to receive one evening dose of study medication or placebo for 14 days. The primary outcome measure was mean change in diurnal IOP, and the key secondary outcome measures included changes in PD, distance-corrected near visual acuity (DCNVA), and conjunctival hyperemia.

RESULTS

Use of 1% PMOS did not lead to a statistically significant decrease in diurnal IOP compared to placebo (P = 0.89) but trended toward a greater decrease in patients with lower IOP baselines. PMOS produced a statistically significant mean 20% PD reduction under both photopic and mesopic conditions that was sustained for 36 hours post-dosing. A statistically significant number of patients with PMOS compared to placebo demonstrated ≥1 line of improvement in photopic DCNVA at day 8 (P = 0.0018), day 15 (P = 0.0072), and day 16 (P = 0.0163), with a trend for 2- and 3-line improvements at all time points. There was no statistical difference in conjunctival hyperemia compared to placebo.

CONCLUSION

Although mean IOP was not lowered significantly, daily evening dosing of 1% PMOS was found to be well tolerated with no daytime conjunctival redness and demonstrated improvement in DCNVA with sustained PD reduction in a glaucomatous and presbyopic population. Smaller pupil size can have beneficial effects in improving symptoms of presbyopia and DLD, which will be the focus of further studies.

NOTCH Signaling Controls Ciliary Body Morphogenesis and Secretion by Directly Regulating Nectin Protein Expression

Anterior segment dysgenesis is often associated with cornea diseases, cataracts, and glaucoma. In the anterior segment, the ciliary body (CB) containing inner and outer ciliary epithelia (ICE and OCE) secretes aqueous humor that maintains intraocular pressure (IOP). However, CB development and function remain poorly understood. Here, this study shows that NOTCH signaling in the CB maintains the vitreous, IOP, and eye structures by regulating CB morphogenesis, aqueous humor secretion, and vitreous protein expression. Notch2 and Notch3 function via RBPJ in the CB to control ICE-OCE adhesion, CB morphogenesis, aqueous humor secretion, and protein expression, thus maintaining IOP and eye structures. Mechanistically, NOTCH signaling transcriptionally controls Nectin1 expression in the OCE to promote cell adhesion for driving CB morphogenesis and to directly stabilize Cx43 for controlling aqueous humor secretion. Finally, NOTCH signaling directly controls vitreous protein secretion in the ICE. Therefore, this study provides important insight into CB functions and involvement in eye diseases.

Intraocular Pressure Telemetry for Managing Glaucoma during the COVID-19 Pandemic

PURPOSE

To evaluate in glaucoma patients the feasibility and use of remote monitoring of intraocular pressure (IOP) with an implanted telemetry sensor during the coronavirus disease 2019 (COVID-19) lockdown.

DESIGN

Cross-sectional study.

PARTICIPANTS

Patients previously implanted with a telemetric IOP sensor (Eyemate; Implandata GmbH) were included.

METHODS

Intraocular pressure measurements acquired by the patients during the lockdown were collected by physicians who were located remotely. A questionnaire was sent to 10 participating study centers to evaluate the clinical impact of remote monitoring of IOP via the IOP sensor system.

MAIN OUTCOME MEASURES

Number of patients who obtained home IOP measurements.

RESULTS

Data were available from all centers and from 37 eyes of 37 patients (16 patients with a sulcus-based sensor and 21 patients with a suprachoroidal sensor). Thirty-four patients obtained IOP measurements during the lockdown. Mean age of the patients was 69.3 ± 9.6 years, and 48.6% were women. A total of 8415 IOP measurements from 370 measurement days were obtained. Based on remote IOP measurements, treatment was changed in 5 patients. In another 5 patients, treatment change was considered when physicians received the IOP measurements after the lockdown. Nine of the 10 study centers judged remote IOP measurements to have a clinical impact.

CONCLUSIONS

These results show the feasibility of patient-acquired measurement of IOP in conjunction with remote IOP monitoring by physicians with an implantable sensor. The data obtained impacted clinical decision making, including adjustment of ocular hypotensive therapy and avoiding unnecessary office visits during the COVID-19 pandemic.

Formulation and investigation of pilocarpine hydrochloride niosomal gels for the treatment of glaucoma: intraocular pressure measurement in white albino rabbits

The present study was focused on investigating niosomal gels loaded with cholinergic drug; pilocarpine HCl, for prolonged precorneal residence time and improved bioavailability for glaucoma treatment. Pilocarpine HCl niosomes were prepared using various nonionic surfactants (span 20, span 60 and span 80), in the presence of cholesterol in different molar ratios by ether injection method. The selected formulations were incorporated into carbopol 934 and locust bean gum-based gels. TEM analysis confirmed that niosomes formed were spherical in shape and has a definite internal aqueous space with uniform particle size. Formulation F4 composed of span 60 and cholesterol (1:1) gave the highest entrapment (93.26 ± 1.75%) and slower release results after 8 hours (Q8h = 60.35 ± 1.87%) among other formulations. The in-vitro drug permeation studies showed that there was a prolonged release of drug from niosomal gels as compared to niosomes itself. Considering the in-vitro drug release, niosomal gel formulation G2 was the best among the studied formulations. The release data were fitted to an empirical equation, which indicated that the release follows non-Fickian diffusion mechanism. The stability study revealed that incorporation of niosomes in gel increased their stability than the niosome itself. No signs of redness, inflammation, swelling or increased tear production were observed over the study period for tested formulation by Draize's test. The intraocular pressure (IOP) lowering activity of G2 formulation showed relative bioavailability 2.64 times more than bioavailability of marketed Pilopine HS® gel. These results suggest that the niosomal gels containing pilocarpine HCl are promising ocular carriers for glaucoma treatment.

Co-delivery of brinzolamide and miRNA-124 by biodegradable nanoparticles as a strategy for glaucoma therapy

Co-delivery nanoparticles with characteristics of intracellular precision release drug have been generally accepted as an effective therapeutic strategy for eye diseases. In this study, we designed a new co-delivery system (miRNA/NP-BRZ) as a lasting therapeutic approach to prevent the neuro-destructive after the long-term treatment of glaucoma. Neuroprotective and intraocular pressure (IOP) response were assessed in in vivo and in vitro models of glaucoma. At the meaning time, we describe the preparation of miRNA/NP-BRZ, drug release characteristics, intraocular tracing, pharmacokinetic and pharmacodynamics study and toxicity test. We found that miRNA/NP-BRZ could remarkably decrease IOP and significantly prevent retinal ganglion cell (RGC) damages. The new formula of miRNA-124 encapsulated in PEG-PSA-BRZ nanoparticles exhibits high encapsulation efficiency (EE), drug-loading capacity (DC), and stable controlled-release efficacy (EC). Moreover, we also verified that the miRNA/NP-BRZ system is significantly neuroprotective and nontoxic as well as lowering IOP. This study shows our co-delivery drug system would have a wide potential on social and economic benefits for glaucoma.