Pseudoexfoliation Glaucoma and its Systemic Association: A Clinical Study

Pseudoexfoliation [PXF] being a age related elastotic process is a well known entity among all ophthalmologists. PXF is most common form of secondary glaucoma. Objective: To study the clinical presentations and response to treatment of PXF glaucoma and also to throw light on its systemic associations. Methods: A total of 70 eyes of PXF glaucoma was considered for the study in duration of 6 months from june to November 2021 at a tertiary care center. All patients underwent detailed ophthalmic evaluation along with gonioscopy, optic disc assessment, visual fields and intraocular pressure. Based on all these , patients were graded as mild, moderate and advanced glaucoma and treated accordingly either with medical or surgical line of management. Patients were followed up for a duration of 6 months. ECG, echocardiography and dermatological evaluation of all the patients were done. Results: Mean age of 70 patients was 52.2 years and there was male preponderance .Powdery greyish white pseudoexfoliative material on pupillary margin was seen in 41 eyes[58.5%] and on anterior capsule was seen in 19 eyes[27.1%]. IOP in these 70 patients ranged between 14 to 40mmHg. Gonioscopy showed exfoliative material deposition in 14 eyes[20%] and increased pigmentation of trabecular meshwork in 44 eyes[62.85%]. Also, it revealed narrow angle( grade 1&2) in 6 eyes and open angle (grade 3&4) in rest .Visual filed changes were present in 57 of 70 eyes with PXF glaucoma. Optic disc changes in PXF glaucoma also showed variations with 17 eyes having CD ratio of<0.5,while 38 eyes had a cupping between 0.6-0.8. Eleven eyes showed advanced cupping of >0.8 while 4 eyes had glaucomatous optic atrophy.60 eyes were treated with medical line while 10 eyes were managed surgically. 4 patients had dermal nodules and diastolic dysfunction was noted in 31 patients. Conclusion: PXF confers a significantly higher risk of developing glaucoma in comparison with the general population and needs close monitering. PXF glaucoma and its systemic associations also has to be considered Keywords: PXF, pseudoexfoliative, ECG

Segmentation Errors in the Measurement of Volumetric Parameters by Swept-Source Anterior Segment Optical Coherence Tomography

Purpose: To investigate the error rate of segmentation in the automatic measurement of anterior chamber volume (ACV) and iris volume (IV) by swept-source anterior segment optical coherence tomography (SS-ASOCT) in narrow-angle and wide-angle eyes.Methods: In this study, fifty eyes from 25 narrow-angle subjects and fifty eyes from 25 wide-angle subjects were enrolled. SS-ASOCT examinations were performed and each SS-ASOCT scan was reviewed, and segmentation errors in the automatic measurement of ACV and IV were classified and manually corrected. Error rates were compared between the narrow-angle and the wide-angle groups, and ACV and IV before and after manual correction were compared.Results: A total of 12,800 SS-ASOCT scans were reviewed. Segmentation error rates of angle recess, iris root, posterior surface of the iris, pupil margin, and anterior surface of the lens were 84.06, 93.30, 13.15, 59.21, and 25.27%, respectively. Segmentation errors of angle recess, iris root, posterior surface of the iris, and pupil margin occurred more frequently in narrow-angle eyes, while more segmentation errors of the anterior surface of the lens were found in wide-angle eyes (all P &lt; 0.001). ACV decreased and IV increased significantly after manual correction of segmentation errors in both groups (all P &lt; 0.01).Conclusion: Segmentation errors were prevalent in the volumetric measurement by SS-ASOCT, particularly in narrow-angle eyes, leading to mismeasurement of ACV and IV.

Case Report: Glaucoma in an Infant With Retinopathy of Prematurity

Retinopathy of prematurity (ROP) is a leading cause of childhood blindness that occurs due to incomplete development of retinal blood vessels in preterm infants. Glaucoma is an ocular comorbidity in some patients with ROP, and it may be associated with immature anterior chamber development, ROP itself, or the treatment for ROP. There have been a few reports of narrow-angle glaucoma after laser treatment for ROP. In this case report, we describe the course of a female infant born at 24 weeks and 5 days of gestational age with treatment-requiring ROP treated with laser photocoagulation who subsequently developed very elevated intraocular pressure and shallow anterior chambers without pupillary block. The patient required bilateral ab externo trabeculotomy for elevated intraocular pressure, which normalized after the procedure. The patient has remained stable at the last follow-up at 51 weeks postmenstrual age. Differing from previous glaucoma presentations in this setting, we illustrate a case of elevated intraocular pressure and anterior chamber narrowing after laser therapy without pupillary block or synechiae. The possible multifactorial etiology of glaucoma in this patient, including incomplete angle development, ischemia, and laser treatment, highlight the need for glaucoma screening in patients with ROP, both in the short and long term.

A Clinical Case of Fitting Scleral Lens for Correction of Pellucid Marginal Degeneration

Background. Pellucid Marginal Degeneration (PMD) is a rare bilateral degenerative corneal disease. It causes corneal ectasia with bilateral, clear, inferior (typically 4 o’clock to 8 o’clock), peripheral corneal thinning. It usually affects about 80% of corneal stroma, which leads to the corneal ectasia above the thinning area as well as provokes the irregular astigmatism and visual impairment that are difficult to correct. Purpose. To study the possibilities of correction and social rehabilitation in a patient with PMD wearing scleral lenses. Materials and methods. The study included a patient with PMD, signs of corneal dysfunction and narrow-angle subcompensated glaucoma in the right eye, and PMD of the cornea resulted in a corneal leukoma – terminal glaucoma in the left eye. In addition to standard ophthalmic methods, we performed corneal topography and optical coherence tomography (OCT). For intraocular pressure measurement, ICARE IOP tonometer was used in several areas of the intact peripheral cornea. Results. Prior to lens fitting, UCVA in the right eye amounted to 0.06. Scleral lens helped achieve a high visual acuity of 0.9–1.0. The lens was well-tolerated by the patient. Conclusion. Scleral lenses may be a good choice for patients with irregular cornea caused by corneal dystrophy. Not only they are easy to use and have a good visual effect, but they also help patients with social rehabilitation.

CyanoHABs: unavoidable evolutionary ecological consequence for low nutrient-requiring cyanobacteria in eutrophic water

The mechanism of cyanobacterial harmful algal blooms (CyanoHABs) is complicated and confusing. One major reason is they are studied primarily from an ecological perspective and on bloom-forming species only. This narrow angle loses a broader evolutionary and ecological context in which CyanoHABs occur and fails to provide information on relevant components to achieve a wholistic understanding. To derive a comprehensive mechanism of CyanoHABs, we examine CyanoHABs through the overlooked evolutionary and ecological lenses: evolutionary radiation, ecological comparison with co-living algae, and recently identified genomic functional repertoire between blooming and non-blooming species. We found key factors: (1) elaborate diverse functional repertoire and low nutrient requirement in cyanobacteria molded by early adaptive evolution, (2) cyanobacteria having lower nutrient requirements than green algae indeed, (3) there is no directed evolution in biological functions toward water eutrophication in cyanobacteria, (4) the CyanoHAB-associated functional repertoire are more abundant and complete in blooming than non-blooming species. These factors lead us to postulate a preliminary mechanism of CyanoHABs as a synergistic quad: superior functional repertoire, established with long adaptive radiation under nutrient-deficient conditions and not evolved toward eutrophic conditions, enables cyanobacteria to efficiently utilize elevated nutrients under current eutrophic regime for excess growth and CyanoHABs thereof, due to their lower nutrient requirements than co-living algae. This preliminary synthesis without doubt needs further empirical testing, which can be undertaken with more comparative studies of multiple species using integrated systems biology approaches.

Assessment of anterior chamber angle changes after phacoemulsification with swept-source OCT

AIM: To assess the changes of anterior chamber angle in patients with shallow anterior chamber after phacoemulsification combined with intraocular lens (IOL) implantation, based on anterior segment swept-source optical coherence tomography (AS-SS-OCT) measurements. METHODS: This was a prospective case control study; sixty eyes of sixty case were scheduled for cataract surgery with normal intraocular pressure (IOP). Based on anterior chamber depth (ACD) and gonioscopy findings, the eyes were divided into two groups: group of shallow anterior chamber and narrow angle (SAC group, 30 eyes); and group of normal anterior chamber group with wide angle (NAC group, 30 eyes). Measurements of ACD, anterior chamber volume (ACV), iris volume (IV), lens vault (LV), angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), and trabecular iris angle (TIA) were conducted in each group before and 3mo after surgery. RESULTS: There was no significant difference in age, axial length (AL), corneal curvature, corneal diameter, intraocular pressure, and IV between two groups before surgery, except for the LV (P=0.000). ACD and ACV were prominently larger in the NAC group than the SAC group 3mo after operation (3.69±0.38 vs 3.85±0.39 mm, P=0.025; 161.37±19.47 vs 178.26±20.30 mm3, P=0.002). AOD750, ARA750 in nasal and inferior quadrants, TISA750 in all quadrants except temporal, and TIA750 in all quadrants in SAC group were significantly smaller than those in NAC group after operation (all P<0.05). CONCLUSION: Cataract surgery can deepen anterior chamber and increase the width of anterior chamber angle in Chinese subjects, but the angle related parameters including AOD750, ARA750, TISA750, TIA, TISA750, and ACV in patients with shallow anterior chamber and narrow angle do not reach the normal level.

Vortex formation and associated aneurysmogenic transverse rotational shear stress near the apex of wide-angle cerebral bifurcations

OBJECTIVE Aneurysm formation preferentially occurs at the site of wide-angle cerebral arterial bifurcations, which were recently shown to have a high longitudinal positive wall shear stress (WSS) gradient that promotes aneurysm formation. The authors sought to explore the other components of the hemodynamic environment that are altered with increasing bifurcation angle in the apical region and the effects of these components on WSS patterns on the vessel wall that may modulate aneurysm genesis and progression. METHODS Parametric models of symmetrical and asymmetrical bifurcations were created with increasing bifurcation angles (45°–240°), and 3D rotational angiography models of 13 middle cerebral artery (MCA) bifurcations (7 aneurysmal, 6 controls) were analyzed using computational fluid dynamics. For aneurysmal bifurcations, the aneurysm was digitally removed to uncover hemodynamics at the apex. WSS vectors along cross-sectional planes distal to the bifurcation apex were decomposed as orthogonal projections to the cut plane into longitudinal and transverse (tangential to the cross-sectional plane) components. Transverse rotational WSS (TRWSS) and TRWSS gradients (TRWSSGs) were sampled and evaluated at the apex and immediately distal from the apex. RESULTS In parametric models, increased bifurcation angle was associated with transverse flow vortex formation with emergence of an associated apical high TRWSS with highly aneurysmogenic positive TRWSSGs. While TRWSS decayed rapidly away from the apex in narrow-angle bifurcations, it remained greatly elevated for many radii downstream in aneurysm-prone wider bifurcations. In asymmetrical bifurcations, TRWSS was higher on the aneurysm-prone daughter vessel associated with the wider angle. Patient-derived models with aneurysmal bifurcations had wider angles (149.33° ± 12.56° vs 98.17° ± 8.67°, p < 0.001), with significantly higher maximum TRWSS (1.37 ± 0.67 vs 0.48 ± 0.23 Pa, p = 0.01) and TRWSSG (1.78 ± 0.92 vs 0.76 ± 0.50 Pa/mm, p = 0.03) compared to control nonaneurysmal bifurcations. CONCLUSIONS Wider vascular bifurcations are associated with a novel and to the authors’ knowledge previously undescribed transverse component rotational wall shear stress associated with a positive (aneurysmogenic) spatial gradient. The resulting hemodynamic insult, demonstrated in both parametric models and patient-based anatomy, is noted to decay rapidly away from the protection of the medial pad in healthy narrow-angle bifurcations but remain elevated distally downstream of wide-angle aneurysm-prone bifurcations. This TRWSS serves as a new contribution to the hemodynamic environment favoring aneurysm formation and progression at wide cerebral bifurcations and may have clinical implications favoring interventions that reduce bifurcation angle.