Abnormal Intraocular Pressure Research Articles

Chemical Insights into Topical Agents in Intraocular Pressure Management: From Glaucoma Etiopathology to Therapeutic Approaches.

Glaucoma encompasses a group of optic neuropathies characterized by complex and often elusive etiopathology, involvihttng neurodegeneration of the optic nerve in conjunction with abnormal intraocular pressure (IOP). Currently, there is no cure for glaucoma, and treatment strategies primarily aim to halt disease progression by managing IOP. This review delves into the etiopathology, diagnostic methods, and treatment approaches for glaucoma, with a special focus on IOP management. We discuss a range of active pharmaceutical ingredients used in glaucoma therapy, emphasizing their chemical structure, pharmacological action, therapeutic effectiveness, and safety/tolerability profiles. Notably, most of these therapeutic agents are administered as topical formulations, a critical aspect considering patient compliance and drug delivery efficiency. The classes of glaucoma therapeutics covered in this review include prostaglandin analogs, beta blockers, alpha agonists, carbonic anhydrase inhibitors, Rho kinase inhibitors, and miotic (cholinergic) agents. This comprehensive overview highlights the importance of topical administration in glaucoma treatment, offering insights into the current state and future directions of pharmacological management in glaucoma.

Manhattan Vision Screening and Follow-Up Study (NYC-SIGHT): Subanalysis of Referral to Ophthalmology

Purpose The Manhattan Vision Screening and Follow-up Study aims to provide access to eye care for underserved populations, detect native rates of ocular pathology, and refer participants with eye disease to ophthalmology. This subanalysis describes the reasons for referral to ophthalmology and identifies risk factors associated with being referred. Methods Enrolled participants were aged ≥40 years, living independently in public housing developments and able to provide consent for eye health screenings. Those with habitual visual acuity 20/40 or worse, intraocular pressure (IOP) 23-29 mmHg, or an unreadable fundus image failed and were scheduled with the on-site optometrist. The optometric exam determined whether further referral to ophthalmology for a clinic exam was warranted. Those with an abnormal image or IOP ≥30 mmHg were referred directly to ophthalmology. Main outcome was factors associated with referral to ophthalmology. Results A total of 708 individuals completed the eye health screening over 15 months. A total of 468 participants were referred to ophthalmology (250 had an abnormal image and 218 were referred by the optometrist). Those referred were predominantly older adults (mean age 70.0 ± 11.4 years), female (66.7%), African American (55.1%) and Hispanic (39.5%). Seventy percent of participants had not had a recent eye exam. Stepwise multivariate logistic regression analysis showed that participants with pre-existing glaucoma (OR 3.14, 95% CI 1.62 to 6.08, p = 0.001), an IOP ≥23 mmHg (OR 5.04, 95% 1.91 to 13.28, p = 0.001), or vision impairment (mild) (OR 2.51, 95% CI 1.68 to 3.77, p = 0.001) had significantly higher odds of being referred to ophthalmology. Conclusion This targeted community-based study in Upper Manhattan provided access to eye care and detected a significant amount of ocular pathology requiring referral to ophthalmology in this high-risk population.

Characteristics and Outcomes of Patients with Scleritis in the IRIS® Registry (Intelligent Research in Sight) Database.

PurposeTo report patient characteristics and factors associated with poor visual acuity and abnormal intraocular pressure (IOP) in patients with scleritis in the American Academy of Ophthalmology’s IRIS® Registry (Intelligent Research in Sight).DesignRetrospective cohort study.ParticipantsPatients in the IRIS Registry with at least 3 office visits associated with an International Classification of Diseases scleritis code from 2013 through 2019.MethodsWe evaluated demographic and clinical characteristics in scleritis and scleritis subtype cohorts. We conducted Cox proportional hazards and multiple logistic regression analyses to assess associations with poor best-corrected visual acuity (BCVA), vision loss, and IOP abnormalities.Main Outcome MeasuresPatient characteristics, BCVA of 0.6 logarithm of the minimum angle of resolution (logMAR) or more, BCVA worsened by more than 3 logMAR units 6 months after presentation, IOP of 30 mmHg or more, and IOP of 5 mmHg or less.ResultsIn this cohort of 111 314 patients with scleritis, the mean ± standard deviation age was 58.5 ± 16.6 years, 66% were women, and 30% had bilateral scleritis. Patients with scleromalacia perforans were older and more likely to have bilateral disease. Multiple logistic regression analysis identified factors with increased odds for poor presenting BCVA (older age, male sex, Black race, Hispanic ethnicity, smoking, and scleritis subtypes) and at least 3 lines of vision loss 6 months after initial scleritis diagnosis (older age, smoking, and anterior scleritis). Cox proportional hazards regression modeling of BCVA of 0.6 logMAR or more showed older age (adjusted hazard ratio [aHR] per 10-year unit, 1.11), Black race (aHR, 1.19), Hispanic ethnicity (aHR, 1.22), active smoking (aHR, 1.39), former smoking (aHR, 1.26), and certain scleritis subtypes increase the risk of poor visual acuity development (P < 0.001 for all). Older age, male sex, Black race, Hispanic ethnicity, smoking, and scleritis subtypes increased the odds of IOP abnormality.ConclusionsOlder age, Black or Hispanic ancestry, smoking, and specific scleritis subtypes are risk factors for worse visual and IOP outcomes in patients with scleritis in the IRIS Registry. Closer follow-up may be appropriate for older, Black, or Hispanic patients with scleritis; smokers should receive smoking cessation assistance.

European Glaucoma Society Terminology and Guidelines for Glaucoma, 5th Edition

European Glaucoma Society Terminology and Guidelines for Glaucoma, 5th Edition

Genetic background modifies vulnerability to glaucoma-related phenotypes in Lmx1b mutant mice.

ABSTRACTVariants in the LIM homeobox transcription factor 1-beta (LMX1B) gene predispose individuals to elevated intraocular pressure (IOP), a key risk factor for glaucoma. However, the effect of LMX1B mutations varies widely between individuals. To better understand the mechanisms underlying LMX1B-related phenotypes and individual differences, we backcrossed the Lmx1bV265D (also known as Lmx1bIcst) allele onto the C57BL/6J (B6), 129/Sj (129), C3A/BLiA-Pde6b+/J (C3H) and DBA/2J-Gpnmb+ (D2-G) mouse strain backgrounds. Strain background had a significant effect on the onset and severity of ocular phenotypes in Lmx1bV265D/+ mutant mice. Mice of the B6 background were the most susceptible to developing abnormal IOP distribution, severe anterior segment developmental anomalies (including malformed eccentric pupils, iridocorneal strands and corneal abnormalities) and glaucomatous nerve damage. By contrast, Lmx1bV265D mice of the 129 background were the most resistant to developing anterior segment abnormalities, had less severe IOP elevation than B6 mutants at young ages and showed no detectable nerve damage. To identify genetic modifiers of susceptibility to Lmx1bV265D-induced glaucoma-associated phenotypes, we performed a mapping cross between mice of the B6 (susceptible) and 129 (resistant) backgrounds. We identified a modifier locus on Chromosome 18, with the 129 allele(s) substantially lessening severity of ocular phenotypes, as confirmed by congenic analysis. By demonstrating a clear effect of genetic background in modulating Lmx1b-induced phenotypes, providing a panel of strains with different phenotypic severities and identifying a modifier locus, this study lays a foundation for better understanding the roles of LMX1B in glaucoma with the goal of developing new treatments.

Manhattan Vision Screening and Follow-up Study in Vulnerable Populations (NYC-SIGHT): Design and Methodology.

The Manhattan Vision Screening and Follow-up Study in Vulnerable Populations is a 5-year prospective, cluster-randomized study to improve detection and management of glaucoma and other eye diseases in vulnerable populations living in affordable housing developments. To describe the study design and methodology of the Manhattan Vision Screening and Follow-up Study in Vulnerable Populations, which aims to investigate whether community-based vision screenings can improve detection and management of glaucoma, vision impairment, cataract, and other eye diseases among vulnerable populations living in affordable housing developments in upper Manhattan. This 5-year prospective, cluster-randomized, controlled trial consists of vision screening and referral for follow-up eye care among eligible residents aged 40 and older. Visual acuity, intraocular pressure (IOP), and fundus photography are measured. Participants with visual worse than 20/40, or IOP 23 to 29 mm Hg, or unreadable fundus images fail the screening and are scheduled with the on-site optometrist. Those with an abnormal image and/or IOP ≥30 mm Hg, are assigned as "fast-track" and referred to ophthalmology. Participants living in 7 developments randomized to the Enhanced Intervention Group who fail the screening and need vision correction receive complimentary eyeglasses. Those referred to ophthalmology receive enhanced support with patient navigators to assist with follow-up eye care. Participants living in 3 developments randomized to the Usual Care Group who fail the screening and need vision correction are given an eyeglasses prescription only and a list of optical shops. No enhanced support is given to the Usual Care Group. All participants referred to ophthalmology are assisted in making their initial eye exam appointment. This study targets vulnerable populations where they live to ensure improved access to and utilization of eye care services in those who are least likely to seek eye care.

Suprachoroidally Delivered DNA Nanoparticles Transfect Retina and Retinal Pigment Epithelium/Choroid in Rabbits.

PurposeThis study evaluated ocular tolerability and transfectability of nonviral DNA nanoparticles (DNPs) after microneedle-based suprachoroidal (SC) administration, in comparison to subretinal (SR) administration.MethodsThe DNPs consisted of a single copy of plasmid DNA with a polyubiquitin C/luciferase transcriptional cassette compacted with 10 kDa PEG-substituted lysine 30-mer peptides (CK30PEG10k). New Zealand White rabbits (n = 4 per group) received a unilateral SC injection (0.1 mL via a microneedle technique) of ellipsoid-shaped DNPs, rod-shaped DNPs, or saline (negative control). A cohort of rabbits (n = 4) also received a single unilateral SR injection (0.05 mL via a transvitreal approach) of rod-shaped DNPs. At day 7, luciferase activity was measured in the retina and retinal pigment epithelium (RPE)–choroid via bioluminescence assay. A cohort of rabbits received a SC injection of analogous DNPs to assess spread of DNP injectate in the suprachoroidal space (SCS) via optical coherent tomography and histology.ResultsSuprachoroidal injection of DNPs resulted in reversible opening of the SCS circumferentially and posteriorly and was generally well tolerated, with no significant ocular examination score changes, intraocular pressure abnormalities, or changes in electroretinography amplitudes on day 7 compared to the baseline. High luciferase activity was observed in the retina and RPE-choroid of eyes that received SC DNPs (rod and ellipsoid shape) and SR DNPs (rod shape) compared to controls. The mean luciferase activity in RPE-choroid and retina was comparable between SC and SR administrations. Transfection in the RPE-choroid was approximately 10-fold higher than in the retina after either SC or SR administration of DNPs.ConclusionsSuprachoroidal and SR administration of DNPs resulted in comparable transfection of retina and RPE-choroid.Translational RelevanceSuprachoroidal delivery of DNPs offers the potential to precisely target chorioretinal tissues while avoiding surgical risks associated with SR injection, and it may offer an office-based nonsurgical gene therapy option for the treatment of retinal diseases.

Visual outcome and intraocular pressure control after cataract surgery in patients with lens induced glaucoma: A longitudinal study at a tertiary care centre

Lens induced glaucoma due to hypermature cataract is an important cause of secondary glaucoma. Lens induced glaucoma is a common cause of ocular morbidity. To determine the visual outcome and study the intraocular pressure control post cataract extraction in patients with lens induced glaucoma. This prospective study was done in patients who underwent cataract surgery with lens induced glaucoma visiting the Tertiary Care Centre in Latur, Maharashtra. Fifty cases of lens induced glaucoma satisfying the inclusion criteria were selected &amp; followed up from the time of admission &amp; surgery till 4 weeks post- operatively and factors influencing the final visual outcome were analysed. Chi-Square test was used for comparison &amp; p-value &amp;#60; 0.05 was considered statistically significant. All the cases included in the study had raised intraocular pressure on admission and 48% patients had intraocular pressure between 30-40 mmHg. It was found that good visual acuity can be achieved in LIG presenting within 2 weeks and IOP less than 35mmHg. Forty four percent had a best corrected visual acuity of 6/6-6/12 post operatively. Cases (100%) having abnormal intraocular pressure on admission had normal intraocular pressure after cataract extraction. Positive correlation between duration of symptoms and pre op IOP to the final best corrected visual acuity was found. Awareness, early diagnosis and efficient medical management can control IOP and inflammation, with meticulous surgery and IOL implantation. Lens induced glaucoma due to hyper mature cataract is an important cause of secondary glaucoma in the developing world. The uptake of eye care services by the rural community has also been suboptimal in countries like India where lens induced glaucoma is a common cause of ocular morbidity.

Relationship between the 24-h variability of blood pressure, ocular perfusion pressure, intraocular pressure, and visual field defect in thyroid associated orbitopathy.

To evaluate the relationship between the 24-h variability of blood pressure (BP), ocular perfusion pressure (OPP), intraocular pressure (IOP), and visual field (VF) defect in thyroid-associated orbitopathy (TAO). Thirty patients (60 eyes) with TAO were clinically examined in the Eye Hospital of Wenzhou Medical University. Patients were divided into two groups: one with VF defect (A) and the other without (B). Clinical parameters measured include 24-h IOP, 24-h blood pressure, orbital computed tomography (CT) scan, optical coherence tomography (OCT), and VFs. The pulse pressure (PP), mean arterial pressure (MAP), mean ocular perfusion pressure (MOPP), and 24-h fluctuations were calculated by formula. The MOPP and MAP fluctuation were greater in group A than B (p< 0.05) and had significant negative correlation to mean deviation (MD) of VF (R= - 0.434 P= 0.001*). There was no statistical difference in the muscle index, medial rectus muscle thickness, and blood pressure between two groups. Although there were no significant differences in the mean IOP and IOP fluctuation between two groups, the incidence of IOP abnormalities has higher trend in group A. Patients with 24-h IOP fluctuation ≥8mmHg and the mean IOP > 21mmHg in the group A were more than group B. Dysthyroid optic neuropathy (DON) might have multiple pathogenic mechanisms. In this study, 24-h MOPP fluctuation and medial rectus maximal diameter were all the risk factors for DON. Higher mean IOP and 24-h IOP fluctuation might be risk factors for DON.

TRPC5 regulates axonal outgrowth in developing retinal ganglion cells

The TRPC5 ion channel is activated upon depletion of intracellular calcium stores, as well as by various stimuli such as nitric oxide (NO), membrane stretch, and cold temperatures. TRPC5 is abundantly expressed in the central nervous system where it has important neuronal functions. In the chick retina, TRPC5 expression was shown to be restricted to amacrine cells (ACs) and Müller glial cells, although its expression was also observed in the ganglion cell layer (GCL) in displaced ACs, as determined by their characteristic cell morphology. However, it is possible that this expression analysis alone might be insufficient to fully understand the expression of TRPC5 in retinal ganglion cells (RGCs). Hence, we analyzed TRPC5 expression by in situ hybridization and immunostaining in the developing mouse retina, and for the first time identified that developing and mature RGCs strongly express TRPC5. The expression begins at E14.5, and is restricted to ACs and RGCs. It was reported that TRPC5 negatively regulates axonal outgrowth in hippocampal neurons. We thus hypothesized that TRPC5 might have similar functions in RGCs since they extend very long axons toward the brain, and this characteristic significantly differs from other retinal cell types. To elucidate its possible involvement in axonal outgrowth, we inhibited TRPC5 activity in developing RGCs which significantly increased RGC axon length. In contrast, overexpression of TRPC5 inhibited axonal outgrowth in developing RGCs. These results indicate that TRPC5 is an important negative regulator of RGC axonal outgrowth. Since TRPC5 is a mechanosensor, it might function to sense abnormal intraocular pressure changes, and could contribute to the death of RGCs in diseases such as glaucoma. In this case, excessive Ca2+ entry through TRPC5 might induce dendritic and axonal remodeling, which could lead to cell death, as our findings clearly indicate that TRPC5 is an important regulator of neurite remodeling.

Recent Progress of Miniature MEMS Pressure Sensors.

Miniature Microelectromechanical Systems (MEMS) pressure sensors possess various merits, such as low power consumption, being lightweight, having a small volume, accurate measurement in a space-limited region, low cost, little influence on the objects being detected. Accurate blood pressure has been frequently required for medical diagnosis. Miniature pressure sensors could directly measure the blood pressure and fluctuation in blood vessels with an inner diameter from 200 to 1000 μm. Glaucoma is a group of eye diseases usually resulting from abnormal intraocular pressure. The implantable pressure sensor for real-time inspection would keep the disease from worsening; meanwhile, these small devices could alleviate the discomfort of patients. In addition to medical applications, miniature pressure sensors have also been used in the aerospace, industrial, and consumer electronics fields. To clearly illustrate the “miniature size”, this paper focuses on miniature pressure sensors with an overall size of less than 2 mm × 2 mm or a pressure sensitive diaphragm area of less than 1 mm × 1 mm. In this paper, firstly, the working principles of several types of pressure sensors are briefly introduced. Secondly, the miniaturization with the development of the semiconductor processing technology is discussed. Thirdly, the sizes, performances, manufacturing processes, structures, and materials of small pressure sensors used in the different fields are explained in detail, especially in the medical field. Fourthly, problems encountered in the miniaturization of miniature pressure sensors are analyzed and possible solutions proposed. Finally, the probable development directions of miniature pressure sensors in the future are discussed.

Visual Outcome and Predictors of Poor Visual Outcome among Uveitis Patients Attended at KCMC Eye Department, Moshi—Northern Tanzania

Background: Uveitis, an inflammatory disease of the middle layer of the human eye is a potentially blinding disease, carrying social, economic and individual consequence. Though not being a leading blinding disease, it causes visual impairment and blindness with its complications like cataract and glaucoma. Few studies have addressed the visual outcome after diagnoses and follow-up of patients with uveitis; and at our setting, few is known about the visual outcome, factors predicting poor outcome. Methodology and Materials: This was a hospital-based cohort study conducted at the Kilimanjaro Christian Medical Center (KCMC), Eye Department. Files of patients attended from January 2010 to December 2017 were assessed. Measures of Central Tendency and their corresponding dispersion were used to summarize continuous variables and proportions for categorical variables. One sample paired t-test was used to assess differences in mean Best Corrected Visual Acuity (BCVA) and Wilcoxon Signed Rank test for differences in median BCVA between the first visit and at one year respectively. Association between predictors and poor outcome was analyzed by using Chi square test. Multivariate regression was used to control for potential confounders and a p value less than 0.05 was considered as statistical significant. Results: A total of 291 patients were assessed, majority of them being female (54.6%), with median age being 53 years. The proportion of visual impairment reduced from the initial 57.7% at presentation to 28.2% at one year. The mean BCVA improved from the initial 0.96 log MAR to 0.70 log MAR at one year. The main factors associated with poor presenting vision were: Cataract (p value < 0.001), Cystoid Macular Edema (CME: p value < 0.001), Maculopathy (p value = 0.042), Keratopathy (p value < 0.001), Posterior Synechiae (PS: p value = 0.044), Abnormal Intraocular Pressure (IOP: p value = 0.036) and non-anterior location (p value = 0.042). At one year, the factors associated with poor outcome were: retinal detachment (p value = 0.022), Glaucoma (p value = 0.018) and Maculopathy (p value = 0.039). Conclusions: at one year of follow-up of patients with uveitis, the proportion of visual impairment reduces significantly, with improvement also being observed on mean visual acuity. The most common predictors of poor visual outcome were Cataract, Glaucoma CME, abnormal IOP and Maculopathy.

Philadelphia Telemedicine Glaucoma Detection and Follow-up Study: confirmation between eye screening and comprehensive eye examination diagnoses

AimsTo evaluate agreement between ocular findings of a telemedicine eye screening (visit 1) with diagnoses of a comprehensive eye examination (visit 2).MethodsA primary care practice (PCP)–based telemedicine screening programme incorporating...

Prediction of postoperative complications of pediatric cataract patients using data mining

BackgroundThe common treatment for pediatric cataracts is to replace the cloudy lens with an artificial one. However, patients may suffer complications (severe lens proliferation into the visual axis and abnormal high intraocular pressure; SLPVA and AHIP) within 1 year after surgery and factors causing these complications are unknown.MethodsApriori algorithm is employed to find association rules related to complications. We use random forest (RF) and Naïve Bayesian (NB) to predict the complications with datasets preprocessed by SMOTE (synthetic minority oversampling technique). Genetic feature selection is exploited to find real features related to complications.ResultsAverage classification accuracies in three binary classification problems are over 75%. Second, the relationship between the classification performance and the number of random forest tree is studied. Results show except for gender and age at surgery (AS); other attributes are related to complications. Except for the secondary IOL placement, operation mode, AS and area of cataracts; other attributes are related to SLPVA. Except for the gender, operation mode, and laterality; other attributes are related to the AHIP. Next, the association rules related to the complications are mined out. Then additional 50 data were used to test the performance of RF and NB, both of then obtained the accuracies of over 65% for three classification problems. Finally, we developed a webserver to assist doctors.ConclusionsThe postoperative complications of pediatric cataracts patients can be predicted. Then the factors related to the complications are found. Finally, the association rules that is about the complications can provide reference to doctors.

The short-term intraocular pressure after 25G+ pars plana vitrectomy and analysis of possible influence factors in rhegmatogenous retinal detachment and proliferative diabetic retinopathy

Objective To observe the short-term intraocular pressure after 25G+ pars plana vitrectomy(PPV) and analyze the possible influencing factors in rhegmatogenous retinal detachment (RRD) and proliferative diabetic retinopathy (PDR) eyes. Methods This is a retrospective case-control study. A total of 160 patients (163 eyes) of RRD and PDR who underwent 25G+ PPV were enrolled in this study. There were 88 males (89 eyes) and 72 females (74 eyes), with the mean age of (50.37±13.24) years. There were 90 patients (92 eyes) with RRD (the RRD group) and 70 patients (74 eyes) with PDR (the PDR group). Best corrected visual acuity (BCVA) and intraocular pressure (IOP) were performed on all the patients. The BCVA was ranged from hand motion to 0.6. The average IOP was (12.61±4.91) mmHg (1 mmHg=0.133 kPa). There were significant differences in crystalline state (χ2=9.285, P=0.009), IOP (χ2=58.45, P=0.000), history of PPV (χ2=4.915, P=0.027) and hypertension (χ2=24.018, P=0.000), but no significant difference in sex (χ2=0.314, P=0.635) and age (χ2=5.682, P=0.056) between the two groups. A non-contact tonometer has been used to measure IOP on postoperative day 1 and 3. The postoperative IOP distribution has been divided into five groups: severe ocular hypotension (≤5 mmHg), mild ocular hypotension (6 - 9 mmHg), normal (10 - 21 mmHg), mild ocular hypertension (22 - 29 mmHg), severe ocular hypertension (≥30 mmHg). Logistic regression analysis has been used to analyze the risk and protective factors. Results On the first day after surgery, there were 21 eyes(12.9%) in mild ocular hypotension, 96 eyes (58.9%) in normal, 22 eyes (13.4%) in mild ocular hypertension and 24 eyes (14.7%) in severe ocular hypertension. On the first day after surgery, there were 18 eyes (11.0%) in mild ocular hypotension, 117 eyes (71.7%) in normal, 23 eyes (14.1%) in mild ocular hypertension and 5 eyes (3.1%) in severe ocular hypertension. There was no significant difference of IOP distribution between the two groups(Z=−1.235, −1.642; P=0.217, 0.101). The results of logistic regression analysis showed that silicone tamponade was a risk factor for ocular hypertension in PDR eyes on the first day after surgery [odds ratio (OR)=15.400, 95% confidence interval (CI) 3.670 - 64.590; P<0.001], while intraocular lens was the risk factor for ocular hypotension in PDR eyes on third day after surgery (OR=19.000, 95%CI 1.450 - 248.2; P=0.025). As for RRD eyes, the ocular hypotension before surgery was a risk factor for ocular hypertension on the third day after surgery (OR=3.755, 95%CI 1.088 - 12.955; P=0.036). For all eyes, silicone tamponade (OR=0.236, 95%CI 0.070 - 0.797), air tamponade (OR=0.214, 95%CI 0.050 - 0.911) and inert gas tamponade (OR=0.092, 95%CI 0.010 - 0.877) were protective factors for ocular hypotension on the first day after surgery (P=0.020, 0.037, 0.038); silicone tamponade was protective factor for ocular hypotension on the third day after surgery (OR=0.249, 95% CI 0.066 - 0.94, P=0.040); while aphakic eyes was the risk factor for ocular hypotension on third day after surgery (OR=7.765, 95% CI 1.377 - 43.794, P=0.020). The ocular hypotension before surgery was a risk factor for ocular hypertension on the third day after surgery (OR=4.034, 95% CI 1.475 - 11.033, P=0.007). Conclusions The abnormal IOP is common after 25G+ PPV with a rate from 28.3% to 31.1%. Silicone tamponade, air tamponade and inert gases tamponade are protective factors for postoperative ocular hypotension, aphakic eye is risk factor for postoperative ocular hypotension. Ocular hypotension before surgery and silicone oil tamponade are risk factors for postoperative ocular hypertension. Key words: Vitreoretinal surgery/adverse effects; Intraocular pressure; Diabetic retinopathy/ surgery; Retinal detachment/surgery; Root cause analysis

Intracranial and Intraocular Pressure During Various Degrees of Head-Down Tilt.

More than half of astronauts develop ophthalmic changes during long-duration spaceflight consistent with an abnormal intraocular and intracranial pressure (IOP, ICP) difference. The aim of our study was to assess IOP and ICP during head-down tilt (HDT) and the additive or attenuating effects of 1% CO2 and lower body negative pressure (LBNP). In Experiment I, IOP and ICP were measured in nine healthy subjects after 3.5 h HDT in five conditions: -6°, -12°, and -18° HDT, -12° with 1% CO2, and -12° with -20 mmHg LBNP. In Experiment II, IOP was measured in 16 healthy subjects after 5 min tilt at +12°, 0°, -6°, -12°, -18°, and -24°, with and without -40 mmHg LBNP. ICP was only found to increase from supine baseline during -18° HDT (9.2 ± 0.9 and 14.4 ± 1 mmHg, respectively), whereas IOP increased from 15.7 ± 0.3 mmHg at 0° to 17.9 ± 0.4 mmHg during -12° HDT and from 15.3 ± 0.4 mmHg at 0° to 18.7 ± 0.4 mmHg during -18° HDT. The addition of -20 mmHg LBNP or 1% CO2 had no further effects on ICP or IOP. However, the use of -40 mmHg LBNP during HDT lowered IOP back to baseline values, except at -24° HDT. A small, posterior intraocular-intracranial pressure difference (IOP > ICP) is maintained during HDT, and a sustained or further decreased difference may lead to structural changes in the eye in real and simulated microgravity.Marshall-Goebel K, Mulder E, Bershad E, Laing C, Eklund A, Malm J, Stern C, Rittweger J. Intracranial and intraocular pressure during various degrees of head-down tilt. Aerosp Med Hum Perform. 2017; 88(1):10-16.

Transgenic TBK1 mice have features of normal tension glaucoma.

Duplication of the TBK1 gene is associated with 1-2% of normal tension glaucoma, a common cause of vision loss and blindness that occurs without grossly abnormal intraocular pressure. We generated a transgenic mouse that has one copy of the human TBK1 gene (native promoter and gene structure) incorporated into the mouse genome (Tg-TBK1). Expression of the TBK1 transgene in the retinae of these mice was demonstrated by real-time PCR. Using immunohistochemistry TBK1 protein was predominantly localized to the ganglion cell layer of the retina, the cell type most affected by glaucoma. More intense TBK1 labelling was detected in the retinal ganglion cells (RGCs) of Tg-TBK1 mice than in wild-type littermates. Tg-TBK1 mice exhibit the cardinal sign of glaucoma, a progressive loss of RGCs. Hemizygous Tg-TBK1 mice (with one TBK1 transgene per genome) had a 13% loss of RGCs by 18 months of age (P = 1.5 × 10-8). Homozygous Tg-TBK1 mice had 7.6% fewer RGCs than hemizygous Tg-TBK1 mice and 20% fewer RGCs than wild-type mice (P = 1.9 × 10-5) at 6 months of age. No difference in intraocular pressures was detected between Tg-TBK1 mice and wild-type littermates as they aged (P > 0.05). Tg-TBK1 mice with extra doses of the TBK1 gene recapitulate the phenotype of normal tension glaucoma in human patients with a TBK1 gene duplication. Together, these studies confirm the pathogenicity of the TBK1 gene duplication in human glaucoma and suggest that excess production of TBK1 kinase may have a role in the pathology of glaucoma.

Lack of effects of intramuscular medetomidine on intraocular pressure in clinically normal cats.

This study aimed to determine the effects of intramuscular medetomidine on the results of tonometry in healthy cats. Sixteen healthy cats were randomly divided into two groups of eight cats. The first group was sedated with intramuscular medetomidine alone (100 µg/kg) and the second group received only saline (0.5 ml/5 kg). Intraocular pressure (IOP) values were measured immediately before (T0) and after the injections at 15 mins (T15) and 25 mins (T25) in both groups. Sedation with medetomidine did not cause a statistically significant change in the mean IOP values. The pretreatment mean ± SD IOPs in the treatment and control groups were 16.2 ± 3.1 and 15.9 ± 4.0 mmHg, respectively. In the medetomidine group the mean ± SD IOPs at T15 and T25 were 16.1 ± 4.1 (P = 0.9) and 14.6 ± 2.2 (P = 0.1). Based on this study in healthy cats, medetomidine may be a good choice as a sedative agent in uncooperative cats when IOP measurements are needed. Further investigations in cats with abnormal IOPs are warranted.

The diagnostic value of orbital magnetic resonance imaging T2-Mapping in patients with active Graves' ophthalmopathy

Objective To study the clinical value of orbital magnetic resonance imaging(MRI) in diagnosis and making a judgment about the curative effect of glucocorticoid in patients with Graves' ophthalmopathy(GO). Methods A total of 106 patients with GO were divided into active GO group or inactive GO group according to whether clinical activity score(CAS)≥3 or not, respectively. T2 relaxation times(T2RTs)(ms) and areas(mm2) of four extra-ocular muscles (EOMs) (superior, inferior, medial, and lateral rectus) were directly measured by MRI T2-Mapping. Correlation analysis of T2RTs and areas with eyeball motility, diplopia, exophthalmus, visual acuity and intraocular pressure(IOP) were also performed. The T2RTs and areas of EOMs before and after intravenous methylprednisolone(iv MP) pulse therapy were recorded, respectively. Results The mean T2RTs(88.9±13.8) and mean areas(58.1±23.8) of EOMs in active GO were significantly greater than those in inactive GO(80.6±10.0 and 46.2±18.6, respectively), bing both significantly greater than those in volunteers with normal eyes(76.2±4.7 and 30.3±6.1, respectively)(P<0.01). Maximal T2RTs and maximal areas of EOMs showed significant positive correlation(P<0.01), and both were positively correlated weakly with CAS, reduced movement of eyeball, diplopia, exophthalmus and loss of visual acuity(P<0.01). On the contrary, maximal T2RTs and maximal areas of EOMs showed negative correlation or no correlation with spontaneous retrobulbar pain, painful eye movement, redness of eyelids and abnormal IOP. Even if 1≤CAS<3, ophthalmic symptoms and signs also showed a positive responses to iv MP in patients with moderate to severe GO as long as prolonged T2RTs occurred at least in one of EOMs. The maximal T2RTs, maximal areas, mean T2RTs and mean areas of EOMs were significantly decreased at the end of iv MP treatment, meanwhile ophthalmic symptoms and signs were obviously improved. Conclusions Prolonged T2RTs, especially accompanied by enlarged area on the identical EOMs is an remarkable symbols of acute inflamed muscles. The findings suggested that the use of prolonged T2RTs can improve diagnostic sensitivity and predict the curative effect of iv MP in patients with moderate to severe GO and CAS≥1. (Chin J Endocrinol Metab, 2015, 31: 327-332) Key words: Graves' ophthalmopathy; Magnetic resonance imaging; Methylprednisolone

Diurnal Intraocular Pressure Fluctuation in Eyes with Angle-closure.

ABSTRACTPurpose: To investigate diurnal intraocular pressure (IOP) fluctuation in eyes with angle-closure.Materials and methods: Seventy-seven eyes of 77 newly diagnosed patients with angle closure [33 subjects with primary angle-closure suspects (PACS), 23 subjects with primary angle-closure (PAC), and 21 subjects with primary angle-closure glau-coma (PACG)] were enrolled after laser peripheral iridotomy for this prospective, cross-sectional study.Goldmann applanation tonometry (GAT) was performed at 08:00, 12:00, 16:00, 20:00, and 04:00 hours. Mean diurnal IOP, peak IOP, trough IOP, and IOP fluctuation (peak-trough) were compared between groups.Results: The mean age of the enrolled subjects was 56.8 ± 5.4 years, with 30 males and 47 females. Intraocular pressure fluctuation was significantly higher in the PACG (7.4 ± 2.8 mm Hg) and PAC (5.5 ± 2.3 mm Hg) groups compared with PACS subjects (4.4 ± 1.5 mm Hg). The highest IOP was recorded at 04:00 hours in all but two patients. Two PACS, 10 PAC and 8 PACG patients, with normal office hour IOP had IOP peaks > 21 mm Hg at night. Twenty-five percent patients (20/77) had abnormal IOP despite good office hour readings.Conclusion: Primary angle-closure glaucoma and PAC eyes showed diurnal IOP fluctuations greater than 5 mm Hg in most subjects, with peak IOP recorded at 04:00 hours. Peak IOP was higher than office hour IOP recordings in subjects with angle-closure. A diurnal variation curve is recommended in these subjects, especially in cases with controlled IOP during office hours.How to cite this article: Bhartiya S, Ichhpujani P. Diurnal Intraocular Pressure Fluctuation in Eyes with Angle-closure. J Curr Glaucoma Pract 2015;9(1):20-23.