Diabetic Retinopathy Assessment Variability Among Eye Care Providers in an Urban Teleophthalmology Program.

BACKGROUND: Teleophthalmology is an evidence-based method for diabetic eye screening. It is unclear whether the type of eye care provider performing teleophthalmology interpretation produces significant variability. INTRODUCTION: We assessed grading variability between an optometrist, general ophthalmologist, and retinal specialist using images from an urban, diabetic retinopathy teleophthalmology program. METHODS: Three readers evaluated digital retinal images in 100 cases (178 eyes from 90 patients with type 2 diabetes). Fisher's exact test, percent agreement, and the observed proportion of positive (Ppos) or negative agreement (Pneg) were used to assess variability. RESULTS: Among cases deemed gradable by all three readers (n = 65), there was substantial agreement on absence of any retinopathy (88% ± 4.6%, Pneg = 0.91-0.95), presence of moderate nonproliferative or worse retinopathy (87% ± 3.9%, Ppos = 0.67-1.00), and presence of macular edema (99% ± 0.9%, Ppos = 0.67-1.00). There was limited agreement regarding presence of referable nondiabetic eye pathology (61% ± 11%, Ppos = 0.21-0.59) and early, nonroutine referral for a follow-up clinical eye exam (66% ± 8.1%, Ppos = 0.19-0.54). Among all cases (n = 100), there was acceptable agreement regarding which had gradable images (77% ± 5.0%, Ppos = 0.50-0.90). DISCUSSION: Inclusion of multiple types of eye care providers as teleophthalmology readers is unlikely to produce significant variability in the assessment of diabetic retinopathy among high-quality images. Greater variability was found regarding image gradability, nondiabetic eye pathology, and recommended clinical referral times. CONCLUSIONS: Our results suggest that more extensive training and uniform referral standards are needed to improve consensus on image gradability, referable nondiabetic eye pathology, and recommended clinical referral times.

A Practical Approach to Retinal Dystrophies.

Genomic approaches to developing new diagnostic and therapeutic strategies in retinal dystrophies are among the most advanced applications of genetics (Tsang SH, Gouras P (1996) Molecular physiology and pathology of the retina. In: Duane TD, Tasman W, Jaeger AE (eds) Duane's clinical opthalmology. Lippincott-Raven, Philadelphia). The notion that "nothing can be done" for patients with retinal dystrophies is no longer true. Electrophysiological testing and autofluorescence imaging help to diagnose and predict the patient's course of disease. Better phenotyping can contribute to better-directed, cost-efficient genotyping. Combining fundoscopy, autofluorescent imaging, and electrophysiological testing is essential in approaching patients with retinal dystrophies. Emerging are new gene-based treatments for these devastating conditions.

A Novel Adaptive Deformable Model for Automated Optic Disc and Cup Segmentation to Aid Glaucoma Diagnosis.

This paper proposes a novel Adaptive Region-based Edge Smoothing Model (ARESM) for automatic boundary detection of optic disc and cup to aid automatic glaucoma diagnosis. The novelty of our approach consists of two aspects: 1) automatic detection of initial optimum object boundary based on a Region Classification Model (RCM) in a pixel-level multidimensional feature space; 2) an Adaptive Edge Smoothing Update model (AESU) of contour points (e.g. misclassified or irregular points) based on iterative force field calculations with contours obtained from the RCM by minimising energy function (an approach that does not require predefined geometric templates to guide auto-segmentation). Such an approach provides robustness in capturing a range of variations and shapes. We have conducted a comprehensive comparison between our approach and the state-of-the-art existing deformable models and validated it with publicly available datasets. The experimental evaluation shows that the proposed approach significantly outperforms existing methods. The generality of the proposed approach will enable segmentation and detection of other object boundaries and provide added value in the field of medical image processing and analysis.

Presence and Risk Factors for Glaucoma in Patients with Diabetes.

Diabetes mellitus represents a growing international public health issue with a near quadrupling in its worldwide prevalence since 1980. Though it has many known microvascular complications, vision loss from diabetic retinopathy is one of the most devastating for affected individuals. In addition, there is increasing evidence to suggest that diabetic patients have a greater risk for glaucoma as well. Though the pathophysiology of glaucoma is not completely understood, both diabetes and glaucoma appear to share some common risk factors and pathophysiologic similarities with studies also reporting that the presence of diabetes and elevated fasting glucose levels are associated with elevated intraocular pressure-the primary risk factor for glaucomatous optic neuropathy. While no study has completely addressed the possibility of detection bias, most recent epidemiologic evidence suggests that diabetic populations are likely enriched with glaucoma patients. As the association between diabetes and glaucoma becomes better defined, routine evaluation for glaucoma in diabetic patients, particularly in the telemedicine setting, may become a reasonable consideration to reduce the risk of vision loss in these patients.

Regional Image Features Model for Automatic Classification between Normal and Glaucoma in Fundus and Scanning Laser Ophthalmoscopy (SLO) Images.

Glaucoma is one of the leading causes of blindness worldwide. There is no cure for glaucoma but detection at its earliest stage and subsequent treatment can aid patients to prevent blindness. Currently, optic disc and retinal imaging facilitates glaucoma detection but this method requires manual post-imaging modifications that are time-consuming and subjective to image assessment by human observers. Therefore, it is necessary to automate this process. In this work, we have first proposed a novel computer aided approach for automatic glaucoma detection based on Regional Image Features Model (RIFM) which can automatically perform classification between normal and glaucoma images on the basis of regional information. Different from all the existing methods, our approach can extract both geometric (e.g. morphometric properties) and non-geometric based properties (e.g. pixel appearance/intensity values, texture) from images and significantly increase the classification performance. Our proposed approach consists of three new major contributions including automatic localisation of optic disc, automatic segmentation of disc, and classification between normal and glaucoma based on geometric and non-geometric properties of different regions of an image. We have compared our method with existing approaches and tested it on both fundus and Scanning laser ophthalmoscopy (SLO) images. The experimental results show that our proposed approach outperforms the state-of-the-art approaches using either geometric or non-geometric properties. The overall glaucoma classification accuracy for fundus images is 94.4% and accuracy of detection of suspicion of glaucoma in SLO images is 93.9 %.

DFPE, partially fluorinated ether: a novel approach for experimental intravitreal tamponade.

PURPOSE: To evaluate decafluoro-di-n-pentyl ether (DFPE) as a vitreous tamponade by examining ocular tolerance in rabbits' eyes. METHODS: Thirteen rabbits were divided into 4 groups after mechanical vitrectomy and were followed up to 12 months. The tamponade remained in the eye for 6 months in group 1 (DFPE) and Group 3 (DFPE and silicone oil) and for 12 months in group 2 (DFPE). Group 4 served as control. RESULTS: In groups 1, 2, and 3, dispersion of the fluid appeared 2 weeks postoperatively. Posterior subcapsular cataracts appeared in rabbits' eyes with large fills of DFPE (>50%). Histologic findings in groups 1 and 2 showed no detectable change in outer nuclear layer thickness. Except for some vacuolations, the inner retina was well preserved in all injected rabbits' eyes. On the electroretinography of injected rabbits' eyes, there was no effect on the a wave amplitude and b wave implicit time, but the b wave amplitude was elevated with statistical significance (P < 0.001) at 1, 3, and 6 months postoperatively but with no statistical significance (P > 0.05) after that period when compared with group 4 and unoperated fellow rabbits' eyes of each group. CONCLUSION: Decafluoro-di-n-pentyl ether demonstrated minimum adverse effects in retinal rabbits; further studies are needed before clinical use as short-term tamponade.

A Mechanistic Model of Aqueous Humor Flow to Study Effects of Angle Closure on Intraocular Pressure.

Purpose: To study the relationship between the circumferential extent of angle closure and elevation in intraocular pressure (IOP) using a novel mechanistic model of aqueous humor (AH) flow. Methods: AH flow through conventional and unconventional outflow pathways was modeled using the unified Stokes and Darcy equations, which were solved using the finite element method. The severity and circumferential extent of angle closure were modeled by lowering the permeability of the outflow pathways. The IOP predicted by the model was compared with biometric and IOP data from the Chinese American Eye Study, wherein the circumferential extent of angle closure was determined using anterior segment OCT measurements of angle opening distance. Results: The mechanistic model predicted an initial linear rise in IOP with increasing extent of angle closure which became nonlinear when the extent of closure exceeded around one-half of the circumference. The nonlinear rise in IOP was associated with a nonlinear increase in AH outflow velocity in the open regions of the angle. These predictions were consistent with the nonlinear relationship between angle closure and IOP observed in the clinical data. Conclusions: IOP increases rapidly when the circumferential extent of angle closure exceeds 180°. Residual AH outflow may explain why not all angle closure eyes develop elevated IOP when angle closure is extensive. Translational Relevance: This study provides insight into the extent of angle closure that is clinically relevant and confers increased risk of elevated IOP. The proposed model can be utilized to study other mechanisms of impaired aqueous outflow.

Effectiveness of Glaucoma Screening and Factors Associated with Follow-up Adherence among Glaucoma Suspects in a Safety-Net Teleretinal Screening Program.

PURPOSE: To evaluate rates and risk factors associated with follow-up adherence to in-person glaucoma evaluations and confirmed glaucoma diagnosis in glaucoma suspects identified through teleretinal diabetic retinopathy screening (TDRS). DESIGN: Retrospective cohort study SUBJECTS: Patients with diabetes identified through teleretinal screening to have large or asymmetric cup-to-disc ratios in a Los Angeles County safety-net primary care-based TDRS program. METHODS: Retrospective chart review was performed to obtain demographic and clinical information for patients with cup-to-disc ratios concerning for glaucoma on TDRS. Patients who completed an in-person follow-up appointment within 1 year of teleretinal screening were adherent. Factors associated with follow-up adherence and diagnosis of glaucoma were analyzed with chi-square and independent t tests along with multivariable logistic regressions. MAIN OUTCOME MEASURES: The proportion of patients with suspected glaucoma who adhered with in-person follow-up examination, proportion of patients with confirmed glaucoma diagnosis, and factors associated with follow-up adherence and glaucoma diagnosis. RESULTS: Eight-hundred seventeen patients with optic discs suspicious for glaucoma were included. Five-hundred thirty-four (65.4%) patients successfully completed an in-person glaucoma evaluation. Among these patients, 62.9% and 24.5% received a diagnosis of glaucoma suspect and glaucomatous optic neuropathy, respectively. Compared with patients aged < 50 years, patients aged 50 to 64 years had 1.57 times higher odds of being adherent with in-person visits (P = 0.036), whereas no difference was seen in those aged ≥ 65 years. For every $10 000 increase in the zip code median income, patients had 11% lower odds of being adherent (P = 0.031). Compared with Latino patients, Black patients had 3.52 times (P < 0.001) higher odds of having confirmed glaucoma. CONCLUSION: The majority of patients referred as glaucoma suspects on TDRS completed a follow-up examination, and nearly a quarter of those examined received a confirmed glaucoma diagnosis. Patients aged ≥ 50 and < 65 years along with those from lower-income neighborhoods were more likely to follow up for an in-person evaluation. Compared with Latino patients, Black patients had a higher risk for a confirmed glaucoma diagnosis. This demonstrates the effectiveness of glaucoma detection in a large-scale TDRS program for a safety-net patient population. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any materials discussed in this article.

Non-Invasive Hybrid Ultrasound Stimulation of Visual Cortex In Vivo.

The optic nerve is the second cranial nerve (CN II) that connects and transmits visual information between the retina and the brain. Severe damage to the optic nerve often leads to distorted vision, vision loss, and even blindness. Such damage can be caused by various types of degenerative diseases, such as glaucoma and traumatic optic neuropathy, and result in an impaired visual pathway. To date, researchers have not found a viable therapeutic method to restore the impaired visual pathway; however, in this paper, a newly synthesized model is proposed to bypass the damaged portion of the visual pathway and set up a direct connection between a stimulated visual input and the visual cortex (VC) using Low-frequency Ring-transducer Ultrasound Stimulation (LRUS). In this study, by utilizing and integrating various advanced ultrasonic and neurological technologies, the following advantages are achieved by the proposed LRUS model: 1. This is a non-invasive procedure that uses enhanced sound field intensity to overcome the loss of ultrasound signal due to the blockage of the skull. 2. The simulated visual signal generated by LRUS in the visual-cortex-elicited neuronal response in the visual cortex is comparable to light stimulation of the retina. The result was confirmed by a combination of real-time electrophysiology and fiber photometry. 3. VC showed a faster response rate under LRUS than light stimulation through the retina. These results suggest a potential non-invasive therapeutic method for restoring vision in optic-nerve-impaired patients using ultrasound stimulation (US).

Super-Resolution Ultrasound Localization Microscopy for Visualization of the Ocular Blood Flow.

OBJECTIVE: The ocular vascular system plays an important role in preserving the visual function. Alterations in either anatomy or hemodynamics of the eye may have adverse effects on vision. Thus, an imaging approach that can monitor alterations of ocular blood flow of the deep eye vasculature ranging from capillary-level vessels to large supporting vessels would be advantageous for detection of early stage retinal and optic nerve diseases. METHODS: We propose a super-resolution ultrasound localization microscopy (ULM) technique that can assess both the microvessel and flow velocity of the deep eye with high resolution. Ultrafast plane wave imaging was acquired using an L22-14v linear array on a high frequency Verasonics Vantage system. A robust microbubble localization and tracking technique was applied to reconstruct ULM images. The experiment was first performed on pre-designed flow phantoms in vitro and then tested on a New Zealand white rabbit eye in vivo calibrated to various intraocular pressures (IOP) - 10 mmHg, 30 mmHg and 50 mmHg. RESULTS: We demonstrated that retinal/choroidal vessels, central retinal artery, posterior ciliary artery, and vortex vein were all visible at high resolution. In addition, reduction of vascular density and flow velocity were observed with elevated IOPs. CONCLUSION: These results indicate that super-resolution ULM is able to image the deep ocular tissue while maintaining high resolution that is comparable with optical coherence tomography angiography. SIGNIFICANCE: Capability to detect subtle changes of blood flow may be clinically important in detecting and monitoring eye diseases such as glaucoma.

Wedge Defects on Optical Coherence Tomography Angiography of the Peripapillary Retina in Glaucoma: Prevalence and Associated Clinical Factors.

PRCIS: Among subjects with glaucoma, wedge-shaped defects on optical coherence tomography angiography (OCTA) were associated with disc hemorrhages (DH), paracentral visual field (VF) defects, increased cup-to-disc ratio (CDR), and thinner retinal nerve fiber layer (RNFL). PURPOSE: To examine determinants of wedge defects on peripapillary OCTA in glaucoma. MATERIALS AND METHODS: A total of 278 eyes of 186 subjects with mild to severe primary open-angle glaucoma underwent 6×6 spectral-domain OCTA imaging of the superficial peripapillary retina from 2016 to 2020 at an academic practice. Wedge defects were defined as focal microvasculature loss that extends outward from the optic nerve in an arcuate, wedge shape. Logistic regression models controlling for intereye correlation identified variables significantly associated with wedge defects. Eyes with profound microvasculature loss in both hemispheres were excluded. Candidate variables included: age, sex, race or ethnicity, diabetes, hypertension, follow-up duration, baseline untreated intraocular pressure, intraocular pressure at time of imaging, DH history, paracentral VF defects, CDR, central corneal thickness, spherical equivalent, VF mean deviation, RNFL thickness, and glaucoma stage. RESULTS: Of 278 eyes, 126 (45.3%) had wedge defects in at least 1 hemisphere. In our multivariable logistic regression model, wedge defects were associated with DH history [odds ratio (OR): 3.19, 95% confidence interval (CI): 1.05-9.69, P=0.041], paracentral VF defects [OR: 4.38 (95% CI: 2.11-9.11), P<0.0001], larger CDR [OR: 1.27 (95% CI: 1.03-1.56), P=0.024, per 0.1 increase], and thinner RNFL [OR: 1.71 (95% CI: 1.25-2.34), P=0.0009, per 10 µm decrease]. CONCLUSION: DH history and paracentral VF defects were independently associated with wedge defects on OCTA, which was present in 45.3% of primary open-angle glaucoma patients. These findings may provide insight into glaucoma pathogenesis.

Restoration of Vision in Severe, Cicatricial, Ocular Surface Disease With the Boston Keratoprosthesis Type II.

PURPOSE: To assess clinical outcomes of patients with severe, cicatricial ocular surface disease (OSD) implanted with the currently marketed design of the Boston keratoprosthesis type II (BK2). DESIGN: Retrospective cohort study. METHODS: Records of consecutive patients undergoing BK2 implantation from June 2009 to March 2021 were assessed for postoperative visual acuity, postoperative complications, device replacement, and additional surgeries. RESULTS: Fifty-six eyes of 53 patients with a mean follow-up of 45.8 months (range, 0.2-134.7 months) were included. Stevens-Johnson syndrome/toxic epidermal necrolysis was the most common indication (49.1%), followed by mucous membrane pemphigoid (39.6%) and other OSD (11.3%). Visual acuity improved from logMAR 2.2 ± 0.5 preoperatively to 1.5 ± 1.2 at final follow-up. Of 56 eyes, 50 saw ≥20/200 at some point postoperatively. Of the eyes with a follow-up of more than 5 years, 50.0% retained a visual acuity of ≥20/200 at their final follow-up. The most common complications over the entire postoperative course (mean ∼4 years) were de novo or worsening glaucoma (41.1%), choroidal effusions (30.3%), retinal detachment (25.0%), and end-stage glaucoma (25.0%). In a univariate analysis, patients who experienced irreversible loss of ≥20/200 visual acuity were more likely to have been previously implanted with an older design of BK2, less likely to be on preoperative systemic immunosuppressive therapy, and less likely to have undergone concurrent glaucoma tube implantation, compared to patients who retained ≥20/200 acuity (P < .04 for all). CONCLUSIONS: Advances in device design and postoperative care have made implantation of BK2 a viable option for corneal blindness in the setting of severe cicatricial OSD.

Intrasession repeatability and intersession reproducibility of peripapillary OCTA vessel parameters in non-glaucomatous and glaucomatous eyes.

OBJECTIVE: To compare intrasession repeatability versus intersession reproducibility of the peripapillary vessel parameters using optical microangiography-based optical coherence tomography angiography (OCTA) in non-glaucomatous and glaucomatous eyes. METHODS: In an observational, longitudinal study, peripapillary OCTA scans were collected to evaluate intrasession repeatability and intersession reproducibility using within-eye coefficient of variation (CVW) and intraclass correlation coefficient (ICC). Images were quantified using a custom research-oriented quantification software calculating vessel area density (VAD) and flux and a commercially developed, clinic-oriented quantification software (Cirrus 11.0, Carl Zeiss Meditec) calculating perfusion density (PD) and flux index (FI). Effect of signal strength on the reliability of OCTA parameters was also evaluated. RESULTS: Among 120 non-glaucomatous eyes, intrasession CVW were 4.2% for VAD, 5.3% for flux, 1.5% for PD and 2.0% for FI. The intersession CVW were 6.5% for VAD, 8.0% for flux, 2.0% for PD and 3.2% for FI. The intrasession ICC ranged from 0.928 to 0.945, and intersession ICC ranged from 0.811 to 0.866. From 118 glaucomatous eyes, intrasession CVW was 9.0% for VAD, 10.3% for flux, 1.7% for PD and 2.3% for FI. The intersession CVW was 12.1% for VAD, 14.2% for flux, 2.3% for PD and 3.5% for FI. The intrasession ICC ranged from 0.904 to 0.972, and intersession ICC ranged from 0.855 to 0.955. Signal strength was significantly positively associated with OCTA vessel parameters (p<0.0001) for both groups. CONCLUSION: Peripapillary OCTA vessel parameters had greater intrasession repeatability compared to intersession reproducibility in both non-glaucomatous and glaucomatous eyes. The built-in commercially developed quantification software demonstrated greater agreement than the custom research-oriented quantification software.

Hemiretinal Asymmetry in Peripapillary Vessel Density in Healthy, Glaucoma Suspect, and Glaucoma Eyes.

PURPOSE: To investigate hemiretinal asymmetry in radial peripapillary capillary vessel area density (VAD) of healthy, glaucoma suspect, and glaucoma eyes of varying severity and its diagnostic utility for glaucoma. DESIGN: Population-based, cross-sectional study. METHODS: Optic disc scans (6 × 6 mm) were collected on optical coherence tomography angiography (OCTA) to obtain VAD and on optical coherence tomography (OCT) to measure circumpapillary retinal nerve fiber layer (RNFL) thickness. Hemiretinal difference in VAD (hdVAD) was defined as the absolute difference between superior and inferior hemiretinal VAD. Age-adjusted multivariable linear regression of hdVAD on glaucoma severity was performed. Areas under curves (AUCs) were calculated from predicted probabilities generated by multiple logistic regression of glaucoma severity on age-adjusted single and combined parameters. RESULTS: A total of 1,043 eyes of 1,043 participants (587 healthy, 270 suspect, 67 mild, 54 moderate, 65 severe glaucoma) were included. After age adjustment, mean hdVAD was similar between healthy and suspect (P = .225), higher in mild vs suspect (P < .001), and higher in moderate vs mild (P = .018), but lower in severe vs moderate (P = .001). AUCs of hdVAD were highest for discriminating mild (0.685) and moderate (0.681) glaucoma from healthy. Combining hdVAD and global RNFL (gRNFL) yielded the highest AUCs of all parameters for mild (0.818) and any POAG (0.859) and resulted in significantly better diagnostic accuracy than either hdVAD or gRNFL alone (P < .05 for all comparisons). CONCLUSIONS: hdVAD is higher in early glaucoma and may help with early detection when damage is focal, but its diagnostic ability appears less robust in advanced glaucoma when damage is diffuse.

Steps to Measurement Floor of an Optical Microangiography Device in Glaucoma.

PURPOSE: To compare dynamic ranges and steps to measurement floors of peripapillary and macular metrics from a complex signal-based optical microangiography (OMAGC) optical coherence tomography angiography (OCTA) device for glaucoma with those of OCT measurements. DESIGN: Cross-sectional study. METHODS: Imaging of 252 eyes from 173 patients with glaucoma and 123 eyes from 92 subjects without glaucoma from a glaucoma clinic was quantified using custom and commercial software. Metrics from OCT (retinal nerve fiber layer [RNFL], ganglion cell/inner plexiform layer [GCIPL]) and OCTA (custom: peripapillary vessel area density [pVAD], macular vessel area density [mVAD], and macular vessel skeleton density [mVSD]; commercial: peripapillary perfusion density [pPDZ], macular perfusion density [mPDZ], and macular vessel density [mVDZ]) were plotted against visual field mean deviation (MD) with linear change-point analyses, measurement floors, and steps to floors. RESULTS: Mean MD (dB) for glaucomatous eyes was -5.77 (-6.45 to -5.10). The number of eyes with mild glaucoma (MD >-6), moderate glaucoma (MD -6 to -12), and severe glaucoma (MD <-12) were 164, 50, and 38, respectively. pPDZ yielded the lowest estimated floor at -26.6 dB (standard error [SE] 1.53), followed by OCTA macular metrics (-25 to -21 dB; SE 1.03) and pVAD (-17.6 dB, SE 1.06). RNFL and GCIPL produced floors at -17.8 (SE 0.927) and -23.6 dB (SE 1.14). The highest number of steps to measurement floor belonged to RNFL (7.20) and GCIPL (7.33), followed by pPDZ (4.25), mVAD (3.87), and mVSD (3.81), with 2.5 or fewer steps for pVAD, mPDZ, and mVDZ. CONCLUSIONS: pPDZ, mVAD, and mVSD had approximately 4 steps within their dynamic ranges, without true measurement floors, and thus may be useful in evaluating advanced glaucomatous progression. Improving OCTA test-retest repeatability could augment number of steps for OCTA metrics, increasing their clinical utility.

Differential Efficacy of Combined Phacoemulsification and Endocyclophotocoagulation in Open-angle Glaucoma Versus Angle-closure Glaucoma.

PRéCIS:: This retrospective study found that combined phacoemulsification and endocyclophotocoagulation reduced intraocular pressure (IOP) to a greater degree in angle-closure glaucoma versus open-angle glaucoma and was effective for all stages of glaucoma. PURPOSE: Endocyclophotocoagulation (ECP) laser treatment of the ciliary processes is believed to decrease IOP by reducing aqueous production. Anecdotal experience in angle-closure glaucoma suggests that it may also lower IOP by opening the drainage angle to promote aqueous outflow. This study sought to evaluate combined phacoemulsification and ECP (phaco/ECP) in eyes with different types and stages of glaucoma. PATIENTS AND METHODS: A Retrospective chart review of eyes that underwent phaco/ECP between October 2010 and December 2016 at one institution was conducted. RESULTS: In 63 eyes of 63 patients with an average of 3.0±1.7 years of follow-up, the 22 eyes with chronic angle-closure glaucoma (CACG) had greater IOP reduction and medication reduction than the 41 eyes with primary open-angle glaucoma at both 1 year (6.4 vs. 2.1 mm Hg, P=0.01; 0.9 vs. 0.2 medications, P=0.04) and final follow-up (6.2 vs. 2.4 mm Hg, P=0.02; 0.9 vs. 0.3 medications, P=0.05). There was no difference in IOP reduction or medication reduction for eyes with mild, moderate, or advanced glaucoma at both 1 year (3.5, 3.9, 0.5 mm Hg, respectively, P=0.18; 0.3, 0.6, 0.4 medications, P=0.58) and final follow-up (3.3, 4.8, 0.7 mm Hg, P=0.11; 0.1, 0.8, 0.4 medications, P=0.14). CONCLUSIONS: Eyes with CACG were more responsive to phaco/ECP in terms of IOP and medication reduction compared with eyes with primary open-angle glaucoma. This finding could be partially or entirely due to concurrent cataract extraction and greater CACG preoperative IOP. Phaco/ECP was effective in all stages of glaucoma.

Hemorrhagic complications from glaucoma surgery in patients on anticoagulation therapy or antiplatelet therapy.

PURPOSE: To determine the incidence of and risk factors for hemorrhagic complications in patients on anticoagulation (ACT) or antiplatelet therapy (APT) having glaucoma surgery. DESIGN: Retrospective case-control study. METHODS: Medical records of patients who had glaucoma surgery between July 1, 1998 and March 31, 2005 were reviewed. Patients who either used ACT/APT continuously throughout the perioperative period or discontinued its use prior to surgery were compared to case-matched control patients who were not on such therapies. Patients on ACT/APT who experienced postoperative hemorrhagic complications were compared to those who did not. Outcome measures included hemorrhagic complications and thromboembolic events. RESULTS: Three hundred and forty-seven patients (eyes) who were on ACT or APT prior to glaucoma surgery had a higher rate of hemorrhagic complications than 347 control patients (10.1% vs 3.7%, respectively, P = .002). Patients on ACT had a higher rate of hemorrhagic complications than patients on APT (22.9% vs 8.0%, respectively, P = .003). Patients who continued ACT during glaucoma surgery had the highest rate of hemorrhagic complications (31.8%) when compared to patients who discontinued ACT prior to surgery or patients who used APT alone (P = .001). Hemorrhagic complications following glaucoma surgery were more frequently associated with preoperative ACT, arrhythmia, and higher preoperative and postoperative intraocular pressures (IOP). CONCLUSION: Chronic ACT/APT was associated with a statistically significant increase in the rate of hemorrhagic complications, and perioperative ACT and a high preoperative IOP are potential risk factors for hemorrhagic complications in patients undergoing glaucoma surgery.

Fundus Densitometry Findings Suggest Optic Disc Hemorrhages in Primary Open-Angle Glaucoma Have an Arterial Origin.

PURPOSE: To analyze optic disc hemorrhages (DH) associated with primary open-angle glaucoma by quantifying their geometric profile and comparing their densitometry with hemorrhages from retinal vein occlusions (RVO) and retinal macroaneurysms (MA), which have venous and arterial sources of bleeding, respectively. DESIGN: Retrospective cross-sectional study. METHODS: Setting: Massachusetts Eye & Ear. POPULATION: Fundus images of DH (n = 40), MA (n = 14), and RVO (n = 25) were identified. Patient clinical backgrounds and demographics were obtained. MAIN OUTCOME MEASURES: Grayscale pixel intensity units of hemorrhages and adjacent arteriole and venule over the same background tissue were measured. Densitometry differentials (arteriole or venule minus hemorrhage [ΔA and ΔV, respectively]) were calculated. The ratios of length (radial) to midpoint width for DH were calculated. Mean ΔA and ΔV between groups were compared with t tests. Multiple linear regression assessed the relation of retinal hemorrhage diagnosis to ΔA and ΔV and of DH shape to ΔA and ΔV. RESULTS: Mean (± standard deviation) ΔA and ΔV for DH (6.9 ± 7.1 and -4.7 ± 8.0 pixel intensity units, respectively) and MA (5.3 ± 5.9 and -6.0 ± 4.6, respectively) were comparable (P ≥ .43). Mean ΔA (14.6 ± 7.7) and ΔV (6.4 ± 6.3) for RVO were significantly higher compared to DH and MA (P < .0001) and remained significant in multivariable analyses. A unit increase in DH length-to-width ratio was associated with 1.2 (0.5) and 1.3 (0.5) pixel intensity unit (standard error) decrease in ΔA and ΔV, respectively (P ≤ .014). CONCLUSIONS: DH have densitometry profiles comparable to MA and different from RVO, suggesting that DH in glaucoma have an arterial origin.

Erythropoietin: a candidate neuroprotective agent in the treatment of glaucoma.

Glaucoma is a progressive optic neuropathy that is the leading cause of irreversible blindness in the world. Although methods to lower intraocular pressure are the mainstay of glaucoma therapy, there are currently no available treatment modalities targeted at neuroprotection. Erythropoietin is a hematopoietic cytokine that has been shown to possess remarkable tissue-protective properties in preclinical models of neurodegeneration. As a result, there is a growing interest to explore the neuroprotective properties of erythropoietin as a possible therapeutic agent in neuropathic diseases of the eye such as glaucoma. Initial results in animal models have been promising, but further studies are needed to fully evaluate the safety and efficacy of this candidate neuroprotective agent in clinical trials.

Acquired Corneal Neuropathy and Photoallodynia Associated With Malposition of an Ex-PRESS Shunt.

PURPOSE: Corneal neuropathy is a recently described disease process that is not well understood and is likely underdiagnosed as a result. This is the first reported case of an acquired corneal neuropathy associated with malposition of an Ex-PRESS shunt. METHODS: A single case report. RESULTS: We report the case of a 50-year-old man with a history of multiple procedures for glaucoma who subsequently developed photoallodynia and corneal neuropathy in association with malposition of an Ex-PRESS shunt in the peripheral cornea. Laser confocal microscopy (HRT3/RCM) of the cornea showed the presence of neuromas, decreased nerve density, and a significant increase of dendritiform immune cells consistent with our diagnosis. Initial treatment with steroid pulse therapy did not result in decreased inflammation or symptomatic improvement leading to surgical explantation of the shunt. One month after surgery, there was noticeable improvement in the patient's pain and photoallodynia (approximately 40%) as well as the abnormalities seen on confocal microscopy. CONCLUSIONS: We hypothesize that poor Ex-PRESS shunt positioning can act as a nidus for corneal inflammation, resulting in corneal neuropathy and lowering of the nociception threshold.