Alpha-adrenergic antagonists and iris dynamics: Challenges and solutions in cataract surgery.

BACKGROUND: Alpha-1 adrenergic receptor antagonists (α1-ARAs) are frequently used in treatment of Hypertension and symptomatic benign prostatic hypertrophy (BPH). Numerous studies have demonstrated the association between α1-ARAs like Tamsulosin and increased surgical risks for patients undergoing cataract surgery. This study aims to identify and study the effects of α1-ARAs on iris parameters and the subsequent operative challenges encountered during cataract surgery. METHODS: A cross-sectional, prospective study involving 30 patients on α1-ARAs planned for cataract surgery and equal number of age and sex matched controls were subjected to evaluation of changes on iris parameters and subsequent challenges in cataract surgery. RESULTS: The study group had statistically significant lesser pupil diameter. Iris thickness at sphincter muscle region (SMR) was similar between groups (P = 0.53). Significantly lower values of iris thickness at dilator muscle region (DMR) found in treated subjects (P = < 0.001). There was statistically significant difference between DMR/SMR ratio of two groups (P < 0.001). Multiple regression analysis revealed longer duration of α1-ARAs treatment correlated with reduced DMR/SMR ratio (P = 0.001; r = 0.47). CONCLUSION: α1-ARAs have implications for pupil size regulation and surgical procedures involving the eye. Tamsulosin is more potent than alfuzosin in inducing IFIS. Systemic α1-ARAs lower values of DMR thickness, DMR/SMR ratio and reduces pupillary diameter. Therefore, ophthalmologists, primary care physicians, urologists, and patients should be aware of the potential difficulties that these drugs pose for cataract surgery.

Postmortem sympathomimetic iris excitability.

BACKGROUND: A reliable estimation of time since death can be important for the law enforcement authorities. The compound method encompassing supravital reactions such as the chemical excitability of the iris can be used to further narrow intervals estimated by temperature-based methods. Postmortem iris excitability was mostly assessed by parasympatholytic or parasympathomimetic substances. Little is known regarding sympathomimetic agents. The present study aims to describe the postmortem iris excitability using the sympathomimetic drug phenylephrine. METHODS: Cadavers were included after body donors gave written informed consent during lifetime. Exclusion criteria were known eye disease, or a postmortem interval exceeding 26 hours. A pupillometer with a minimum measurement range of 0.5 mm was used to determine the horizontal pupil diameter before and 20 minutes after the application of phenylephrine. Increase in pupil diameter was labeled as positive reaction, unchanged pupil diameter was labeled as negative reaction, and decrease in pupil diameter was labeled as paradox reaction. RESULTS: 30 eyes from 16 cadavers (median age = 80.0; 9 males, 7 females) were examined. Initial pupil size was in median 3.5 mm (interquartile range [IQR]: 3.0-4.5 mm) and progressed to 4.0 mm (IQR: 3.5-5.0 mm) 20 minutes after drug instillation. The achieved pupil diameter difference comprised in median 0.5 mm (IQR: 0.0-1.0 mm). A positive reaction was observed in 21 cases. Negative reactions were observed in 5 cases and paradox reactions in 4 cases. Overall, there was a statistically significant difference in diameter between the initial and the reactive pupil (P = 0.0002). CONCLUSION: Although relatively rarely used, sympathomimetic drugs seem to be eligible for chemical postmortem iris excitability. Currently, assessment of postmortem iris excitability usually only involves parasympatholytic and parasympathomimetic agents. The findings of the present study give a hint that the application of a third agent with a sympathomimetic mechanism of action could provide additional information. Further studies assessing such a triple approach in the compound method in comparison with the current gold standard for estimation of time since death are mandatory to ensure reliable results.

Efficacy and effect of intracameral adrenaline infusion on pulse rate and blood pressure during phacoemulsification in patients with dark irides.

OBJECTIVE: Phacoemulsification is the most common cataract surgery that needs optimum circumstances in the field of surgery. This comparative pre- and postoperative study assessed the efficacy and safety of using adrenaline in the irrigating solution as an adjunct to preoperative topical mydriatics in dark irides during Phaco surgery. PATIENTS AND METHODS: This was a prospective observational study that enrolled 421 cataract patients (421 eyes) with dark irides, who were scheduled for Phaco surgery from January 2019 to August 2020. All patients received intraoperative irrigation of a balanced salt solution containing adrenaline. The pulse rate and systolic and diastolic blood pressure of all patients were recorded pre- and postoperatively. In addition, the presence of intraoperative floppy-iris syndrome (IFIS), need for pupil mechanical dilatation, and incidence of posterior capsular rupture were recorded. RESULTS: The sample consisted of 421 patients (421 eyes) all had dark irides. Pulse rate and systolic and diastolic blood pressure did not significantly increase post-operatively (p <0.001). Mechanical dilatation of the pupil was performed in one patient (0.24%) and seven eyes (1.66%) were found to have IFIS. There was no case of posterior capsule rupture. CONCLUSIONS: In comparison with the use of preoperative topical mydriatics alone, adding intracameral adrenaline to the irrigation fluid maintains better pupillary dilatation throughout Phacoemulsification surgery, thereby providing better clinical outcomes in dark irides, even in those with IFIS. Its use has no incremental effect on either blood pressure or pulse rate.

UVR-B-induced NKR-1 Expression in Ocular Tissues is blocked by Substance P Receptor Antagonist Fosaprepitant in the Exposed as well as Unexposed Partner Eye.

Purpose: To investigate the effect of NKR-1 antagonists in an established UVR-B-induced cataract mouse model. Furthermore, to examine the expression of pro-inflammatory cytokines/chemokines in mouse eyes following unilateral UVR-B exposure.Methods: Mice received intraperitoneally injections of Fosaprepitant and Spantide I, before and after unilateral exposure to UVR-B. After day 3 and 7 post-exposure, ocular tissues were extracted for the detection of NKR-1 protein level by ELISA.Results: Pretreatment with Fosaprepitant decreases NKR-1 expression in exposed ocular tissues as well as in the unexposed lens epithelium compared to the saline group. Spantide I treatment showed a tendency of NKR-1 overexpression in ocular tissues.Conclusion: The clinically approved NKR-1 receptor antagonist Fosaprepitant decreases NKR-1 protein expression effectively not only in the exposed but also in the unexposed partner eye in a UVR-B irradiation mouse model. No effect was seen on the protein concentration of pro-inflammatory cytokines/chemokines in either eye.

The efficacy and safety of intravitreal conbercept combined with mitomycin C augmented trabeculectomy for treating neovascular glaucoma.

AIM: To investigate the efficacy and safety of intravitreal Conbercept (IVC) and trabeculectomy for treating neovascular glaucoma (NVG). METHODS: We retrospectively reviewed a total of 29 eyes from 29 NVG patients. All patients received preoperative IVC combined with mitomycin C (MMC) augmented trabeculectomy with a 12-month follow-up. The best-corrected visual acuities (BCVA), intraocular pressure (IOP), and cumulative survival rate were calculated. RESULTS: All 29 cases had complete regression of iris neovascularization at 7 days after the combination treatment, and 2 cases had residual iris neovascularization which regressed completely 1 month later. IOP decreased while BCVA improved significantly following the combination treatment. The success rates were 96.6%, 93.1%, 89.7%, 86.2%, and 82.8% at 1 week, 1, 3, 6, and 12 months after trabeculectomy, respectively. IVC injection combined trabeculectomy had few complications. CONCLUSIONS: IVC injection of conbercept combined with trabeculectomy is effective and safe for the treatment of NVG.

Circadian Regulation of IOP Rhythm by Dual Pathways of Glucocorticoids and the Sympathetic Nervous System.

Purpose: Elevated IOP can cause the development of glaucoma. The circadian rhythm of IOP depends on the dynamics of the aqueous humor and is synchronized with the circadian rhythm pacemaker, that is, the suprachiasmatic nucleus. The suprachiasmatic nucleus resets peripheral clocks via sympathetic nerves or adrenal glucocorticoids. However, the detailed mechanisms underlying IOP rhythmicity remain unclear. The purpose of this study was to verify this regulatory pathway. Methods: Adrenalectomy and/or superior cervical ganglionectomy were performed in C57BL/6J mice. Their IOP rhythms were measured under light/dark cycle and constant dark conditions. Ocular administration of corticosterone or norepinephrine was also performed. Localization of adrenergic receptors, glucocorticoid receptors, and clock proteins Bmal1 and Per1 were analyzed using immunohistochemistry. Period2::luciferase rhythms in the cultured iris/ciliary bodies of adrenalectomized and/or superior cervical ganglionectomized mice were monitored to evaluate the effect of the procedures on the local clock. The IOP rhythm of retina and ciliary epithelium-specific Bmal1 knockout mice were measured to determine the significance of the local clock. Results: Adrenalectomy and superior cervical ganglionectomy disrupted IOP rhythms and the circadian clock in the iris/ciliary body cultures. Instillation of corticosterone and norepinephrine restored the IOP rhythm. ß2-Adrenergic receptors, glucocorticoid receptors, and clock proteins were strongly expressed within the nonpigmented epithelia of the ciliary body. However, tissue-specific Bmal1 knock-out mice maintained their IOP rhythm. Conclusions: These findings suggest direct driving of the IOP rhythm by the suprachiasmatic nucleus, via the dual corticosterone and norepinephrine pathway, but not the ciliary clock, which may be useful for chronotherapy of glaucoma.

UPARANT is an effective antiangiogenic agent in a mouse model of rubeosis iridis.

Puncture-induced iris neovascularization (rubeosis iridis; RI) in mice is associated with upregulation of extracellular matrix (ECM) degradation and inflammatory factors. The anti-angiogenic and anti-inflammatory efficacy of UPARANT in reducing RI was determined by noninvasive, in vivo iris vascular densitometry, and confirmed in vitro by quantitative vascular-specific immunostaining. Intravitreal administration of UPARANT successfully and rapidly reduced RI to non-induced control levels. Molecular analysis revealed that UPARANT inhibits formyl peptide receptors through a predominantly anti-inflammatory response, accompanied with a significant reduction in ECM degradation and inflammation markers. Similar results were observed with UPARANT administered systemically by subcutaneous injection. These data suggest that the tetrapeptide UPARANT is an effective anti-angiogenic agent for the treatment of RI, both by local and systemic administrations. The effectiveness of UPARANT in reducing RI in a model independent of the canonical vascular endothelial growth factor (VEGF) proposes an alternative for patients that do not respond to anti-VEGF treatments, which could improve treatment in proliferative ocular diseases. KEY MESSAGES: UPARANT is effective in the treatment of rubeosis iridis, both by local and systemic administrations. UPARANT can reduce VEGF-independent neovascularization.

The effect of cycloplegia on biometric measurements using swept-source optical coherence tomography-based biometry.

BACKGROUND: To evaluate the effect of pupil dilation obtained with cyclopentolate on biometric measurements using swept-source optical coherence tomography biometry. METHODS: This study involved 63 eyes of 63 healthy volunteers. After ophthalmic examination, biometry measurements of the participants were obtained with IOL Master 700 (Carl Zeiss Meditec AG, Jena, Germany). After pre-dilation measurements were taken, subjects were given one drop of cyclopentolate hydrochloride ophthalmic solution three times at 10-minute intervals. When cycloplegia had been achieved, a dilated fundus examination was conducted and post-dilation measurements were taken with IOL Master 700. The biometric parameters were recorded and SPSS Software 22.0 was used for statistical analysis. RESULTS: There was a significant increase in anterior chamber depth, anterior aqueous depth and central corneal thickness values after pupil dilation (p < 0.05). A significant decrease was observed in lens thickness values after cycloplegia (p < 0.05). There were no statistically significant differences between pre-dilation and post-dilation axial length, keratometry (K1, K2) and white-to-white values (p > 0.05). CONCLUSION: This study demonstrated there is no significant difference in axial length and keratometry measurements using swept-source optical coherence tomography biometry before and after cycloplegia.

A synthetic glycosaminoglycan mimetic blocks HSV-1 infection in human iris stromal cells.

Herpes simplex virus type-1 (HSV-1) is a significant pathogen that affects vision by targeting multiple regions in the human eye including iris. Using a focused library of synthetic non-saccharide glycosaminoglycan mimetics (NSGMs), we identified sulfated pentagalloylglucoside (SPGG) as a potent inhibitor of HSV-1 entry and cell-to-cell spread in the primary cultures of human iris stromal (HIS) cells isolated from eye donors. Using in vitro ß-galactosidase reporter assay and plaque reduction assay, SPGG was found to inhibit HSV-1 entry in a dosage-dependent manner (IC50 ∼6.0 µM). Interestingly, a pronounced inhibition in HSV-1 entry and spread was observed in HIS cells, or a cell line expressing specific gD-receptor, when virions were pre-treated with mimetics suggesting a possible interaction between SPGG and the HSV-1 glycoprotein. To examine the significance of gD-SPGG interaction, HIS cells were pretreated with SPGG, which showed a significant reduction in gD binding. Taken together, our results provide strong evidence of SPGG being a novel viral entry inhibitor against ocular HSV infection.

Effects of sustained daily latanoprost application on anterior chamber anatomy and physiology in mice.

Latanoprost is a common glaucoma medication. Here, we study longitudinal effects of sustained latanoprost treatment on intraocular pressure (IOP) in C57BL/6J mice, as well as two potential side-effects, changes in iris pigmentation and central corneal thickness (CCT). Male C57BL/6J mice were treated daily for 16 weeks with latanoprost. Control mice were treated on the same schedule with the preservative used with latanoprost, benzalkonium chloride (BAK), or handled, without ocular treatments. IOP and CCT were studied at pre-treatment, 2 "early" time points, and 2 "late" time points; slit-lamp analysis performed at a late time point; and expression of corneal and iridial candidate genes analyzed at the end of the experiment. Latanoprost lowered IOP short, but not long-term. Sustained application of BAK consistently resulted in significant corneal thinning, whereas sustained treatment with latanoprost resulted in smaller and less consistent changes. Neither treatment affected iris pigmentation, corneal matrix metalloprotease expression or iridial pigment-related genes expression. In summary, latanoprost initially lowered IOP in C57BL/6J mice, but became less effective with sustained treatment, likely due to physiological adaptation. These results identify a new resource for studying changes in responsiveness associated with long-term treatment with latanoprost and highlight detrimental effects of commonly used preservative BAK.

Effects of Post-Treatment Hydrogen Gas Inhalation on Uveitis Induced by Endotoxin in Rats.

BACKGROUND Molecular hydrogen (H2) has been widely reported to have benefiicial effects in diverse animal models and human disease through reduction of oxidative stress and inflammation. The aim of this study was to investigate whether hydrogen gas could ameliorate endotoxin-induced uveitis (EIU) in rats. MATERIAL AND METHODS Male Sprague-Dawley rats were divided into a normal group, a model group, a nitrogen-oxygen (N-O) group, and a hydrogen-oxygen (H-O) group. EIU was induced in rats of the latter 3 groups by injection of lipopolysaccharide (LPS). After that, rats in the N-O group inhaled a gas mixture of 67% N2 and 33% O2, while those in the H-O group inhaled a gas mixture of 67% H2 and 33% O2. All rats were graded according to the signs of uveitis after electroretinography (ERG) examination. Protein concentration in the aqueous humor (AqH) was measured. Furthermore, hematoxylin-eosin staining and immunostaining of anti-ionized calcium-binding adapter molecule 1 (Iba1) in the iris and ciliary body (ICB) were carried out. RESULTS No statistically significant differences existed in the graded score of uveitis and the b-wave peak time in the Dark-adapted 3.0 ERG among the model, N-O, and H-O groups (P>0.05), while rats of the H-O group showed a lower concentration of AqH protein than that of the model or N-O group (P<0.05). The number of the infiltrating cells in the ICB of rats from the H-O group was not significantly different from that of the model or N-O group (P>0.05), while the activation of microglia cells in the H-O group was somewhat reduced (P<0.05). CONCLUSIONS Post-treatment hydrogen gas inhalation did not ameliorate the clinical signs, or reduce the infiltrating cells of EIU. However, it inhibited the elevation of protein in the AqH and reduced the microglia activation.

Post-mortem chemical excitability of the iris should not be used for forensic death time diagnosis.

Post-mortem chemical excitability of the iris is one of the non-temperature-based methods in forensic diagnosis of the time since death. Although several authors reported on their findings, using different measurement methods, currently used time limits are based on a single dissertation which has recently been doubted to be applicable for forensic purpose. We investigated changes in pupil-iris ratio after application of acetylcholine (n = 79) or tropicamide (n = 58) and in controls at upper and lower time limits that are suggested in the current literature, using a digital photography-based measurement method with excellent reliability. We observed "positive," "negative," and "paradox" reactions in both intervention and control conditions at all investigated post-mortem time points, suggesting spontaneous changes in pupil size to be causative for the finding. According to our observations, post-mortem chemical excitability of the iris should not be used in forensic death time estimation, as results may cause false conclusions regarding the correct time point of death and might therefore be strongly misleading.

The Effects of Systemic Alfuzosin and Tamsulosin Hydrochloride on Choroidal Thickness and Pupil Diameter Sizes in Cases with Benign Prostatic Hyperplasia.

PURPOSE: To compare the effects of alfuzosin hydrochloride and tamsulosin hydrochloride on choroidal thickness (CT) and pupil diameter (PD) sizes in patients with benign prostatic hyperplasia. SUBJECTS AND METHODS: Sixty-three men patients with newly diagnosis of benign prostatic hyperplasia were randomly assigned to either alfuzosin hydrochloride or to tamsulosin hydrochloride groups in this prospective, randomized, parallel-group clinical trial. Enhanced depth imaging spectral-domain optical coherence tomography, pupillography were obtained at baseline, 1st and 3rd month, and choroidal thicknesses and pupil diameter sizes were compared between the two groups. RESULTS: The mean subfoveal choroidal thickness (SCT), nasal choroidal thickness (NCT), and temporal choroidal thickness (TCT) in AH group were 275.70 ± 32.14 µm, 269.7 ± 33.54 µm and 270.71 ± 33.52 µm at baseline, respectively; and they were 275.46 ± 31.6 µm, 268.73 ± 33.08 µm and 270.73 ± 33.05 µm at baseline in TH group, respectively (P = 0.97, P = 0.84, P = 0.99, for SCT, NCT, and TCT, respectively). The mean SCT, NCT, and TCT after 3 months were 278.93 ± 34.58 µm, 272.62 ± 34.17 µm, and 273.6 ± 34.17 µm in AH group, respectively; and they were 274.36 ± 31.91 µm, 264.70 ± 33.59 µm, and 267.72 ± 33.6 µm in TH group, respectively (P = 0.6, P = 0.37, P = 0.43, for SCT, NCT, and TCT, respectively). The mean scotopic pupil diameter (SPD), mesopic pupil diameter (MPD), and photopic pupil diameter (PPD) sizes in AH group were 6.46 ± 0.84 mm, 5.07 ± 0.72 mm and 3.66 ± 0.46 mm at baseline, respectively; and they were 6.44 ± 1.14 mm, 5.01 ± 0.79 mm and 3.62 ± 0.53 mm at baseline in TH group, respectively (P = 0.89, P = 0.74, P = 0.68, for SPD, MPD, and PPD, respectively). The mean SPD, MPD, and PPD sizes after 3 months were 5.96 ± 0.76 mm, 4.67 ± 0.74 mm, and 3.15 ± 0.47 mm in AH group, respectively; and they were 6.42 ± 0.89 mm, 5.05 ± 0.75 mm, and 3.55 ± 0.53 mm in TH group respectively (P = < 0.001, P = < 0.001, P = < 0.001, for SPD, MPD, and PPD, respectively). CONCLUSION: The repeated measure of ANOVA for the mean CT values within AH group showed statistically significant increases in baseline CTs, although these differences did not reach statistical significance between 2 groups at follow-ups. We found significant different outcomes for PD sizes during study in the groups. The mean outcome in this study is that using αAR antagonists have potential effects on CT and PD sizes. Abbreviations and Acronyms: AH: alfuzosin hyrdrochloride; ANOVA: analyses of variance; AR: adrenergic receptor; BCVA: best-corrected visual acuity; BPH: benign prostatic hyperplasia; CT: choroidal thickness; EDI-OCT: enhanced depth imaging spectral-domain optical coherence tomography; IFIS: intraoperative floppy iris syndrome; MPD: mesopic pupil diameter; NCT: nasal choroidal thickness; PD: pupil diameter; PPD: photopic pupil diameter; SCT: subfoveal choroidal thickness; SPD: scotopic pupil diameter; TCT: temporal choroidal thickness; TH: tamsulosin hydrochloride.

A 5-Minute Interval between Two Dilating Eye Drops Increases Their Effect.

PURPOSE: Patients are usually advised to wait 5 minutes between eye drops. This delay supposedly allows the first drop not to be washed out by the second one, thereby increasing the combined effect. However, in the only experimental study conducted in humans on the concurrent administration of two different eye drops, the authors concluded that a 10-minute time interval between eye drops did not increase their combined effect. Our study was designed to address this puzzling observation. METHODS: Using digital photographs shot in photopic conditions in 40 eyes of 20 healthy volunteers, we compared relative pupil surface (i.e., pupil to iris surface area ratios) before and after the administration of one drop of 10% phenylephrine and one drop of 0.5% tropicamide either immediately or after a 5-minute time interval. RESULTS: Waiting 5 minutes yielded a 5.6% relative pupil surface gain (observer 1: P = .003, observer 2: P = .005) indicating an additional combined effect with a 5-minute time interval. CONCLUSIONS: These results show a detectable additive effect that is probably the result of methodological refinements including the challenging of the mydriasis by photopic conditions and the use of pupil and iris surface areas, which may show differences that would be undetectable in terms of diameter.