The Complications of Cataract Surgery in Patients with Pseudoexfoliation

The senile cataract represents the blurring of the crystalline lens after the age of 65. It occurs due to metabolic changes in the crystalline lens which occur over the years. The only effective way to treat cataract is the surgical one. Pseudoexfoliation is an age related systemic disorder. PEX represents the accumulation fibrillar material in the extracellular matrix of the tissue. The most known ocular manifestation of the PEX are the collection at iris pupillary margin and anterior lens capsule. This accumulation is associated with many intraoperative and postoperative complications in patients scheduled for cataract surgery. The aim of the study was to investigate the prevalence of the surgical complications during phacoemulsfication in patients with PEX. The study included 91 patients scheduled for cataract surgery divided into two groups (PEX group 46, control group 45 patients). Poor intraoperative midryasis, zonular dehiscence, postoperative corneal edema, anterior chamber inflammation, elevated intraocular pressure and tear film instability had particularly higher rate of occurring in PEX group comparing to the control group (p<0.001). The highest mean value of intraocular pressure was observed in PEX group on the first postoperative day 25.6 ± 1.1 mmHg, while the best corrected visual acuity was measured in control group 0.71 ± 1.2 one month after phacoemulsification. Cataract surgery in patients with PEX carries great risk, but with adequate preoperative planning, the awareness of the potential complications, can provide safe and routine phacoemulification in these patients.

Electron microscopy analysis of femtosecond laser-assisted capsulotomy before and after lens fragmentation

Studying anterior lens capsule cutting edge profiles from femtosecond laser-assisted capsulotomy procedures performed before and after lens fragmentation. Twenty eyes (10 patients) with age-related cataract underwent femtosecond laser-assisted surgery (FLACS) using the Ziemer Z8 platform. First step of laser surgery was either capsulotomy (group first) or fragmentation (group second). One eye of each patient was assigned randomly, the second eye treated with the different sequence of procedures. After anterior capsule removal, tissue was fixed in cacodylate-buffered solution and cutting-edge profiles were analysed using scanning electron microscopy (SEM). All cases had cataract grade 2 and 3 based on LOCS III grading. SEM analysis showed more smooth edges in the first group, especially in cases with pseudoexfoliation (P = 0.037); more tags and bridges and a significant number of staggered cutting patterns (7 out of 10 cases) in the second group. All cases evolved the same microgroves with “valleys and mountains “ as signs of the photodisruption process. Femtosecond laser capsulotomy should be performed before lens fragmentation minimizing the rate of cutting errors. Especially in eyes with advanced cataract, as intracapsular pressure may increase due to lens fragmentation without anterior capsular opening.

Posterior Approach in Management of Phacomorphic Angle Closure

This article presents a case of posterior lensectomy through 3-port pars plana vitrectomy for the management of phacomorphic angle closure. A 67-year-old man presented to the outpatient department with headache and decreased vision in his left eye for the past 3 days. Visual acuity 2/60, intraocular pressure (IOP) &#x3e;60 mm Hg, and the anterior chamber (AC) depth Van Herick grade 1. A complete ophthalmologic examination revealed a phacomorphic angle closure. Serial management was performed consisting of mannitol 20% intravenously, laser peripheral iridotomy, and trabeculectomy. However, the depth of the AC became more shallow, and the IOP remained high. Lens extraction as definitive therapy could not be performed because of the adhesion of the iris and anterior lens capsule to the corneal endothelium; thus, posterior lensectomy using 3-port pars plana vitrectomy, and phacofragmatome was performed. Once the corneal thickness was returned to normal, and the AC depth was sufficient, the patient underwent secondary intraocular lens implantation. A significant improvement in visual acuity, normal IOP, and AC depth were achieved after the management of the posterior approach. Thus, this posterior approach should be considered a good option of management technique in cases with phacomorphic angle closure with very shallow AC depth and a fragile cornea.

Modified capsulorhexis for fluid-filled mature cataracts

Background: The aim of this study was to develop a modified capsulorhexis technique featuring a new maneuver for the removal of subcortical fluid in fluid-filled mature cataracts to avoid high intralenticular pressure. Methods: This prospective interventional study included 33 eyes with mature cataracts and evidence of subcapsular fluid spaces by slit lamp examination. For each patient, 20% mannitol was administered intravenously according to the bodyweight 1 h preoperatively. Under peribulbar anesthesia, a 2.2-mm main incision was made, and the anterior chamber was filled with a dispersive ophthalmic viscosurgical device. Using a bent-tip cystotome, a 2-mm curved incision was made in the center of the anterior capsule, which released subcortical fluid and was drained through compression of the posterior lip of the main incision using a spatula. Then, fine gentle milking in all quadrants around the puncture on the anterior lens capsule from the periphery toward the site of puncture using the blunt-edged spatula further assists drainage of subcortical fluid and breaks fine septa inside the lens to remove fluid from intralenticular fluid pocket collections. Results: The study included 15 (45.5%) men and 18 (54.5%) women with a mean ± standard deviation (SD) of age of 63.2 ± 5.33 and 64.4 ± 6.21 years, respectively. The modified capsulorhexis technique was performed for 33 intumescent cataracts. Capsulorhexis was completed in all cases; capsulorhexis was easy in 31 (94%) eyes and difficult in 2 (6%) eyes. In the two difficult cases, radial extension occurred in one eye, and it was retrieved using the Little technique; the other case with radial tear was completed successfully using a retinal micro scissor from the other edge of the capsulorhexis until reaching an oval, continuous capsulorhexis. Conclusions: This modified capsulorhexis technique with compression on the posterior lip of the main incision and capsule milking allowed for a safe, continuous curvilinear capsulorhexis. Further comparative studies are necessary to confirm our preliminary results. How to cite this article: Ghoneim EM. Modified capsulorhexis for fluid-filled mature cataracts. Med Hypothesis Discov Innov Ophthalmol. 2021 Summer; 10(2): 17-24. https://doi.org/10.51329/mehdioptometry1422

Lens-Related Ocular Emergencies (LROE) in Dogs: Treatment and Visual Outcome

Background Lens-related emergencies need immediate medical intervention to reduce complications, minimize pain, and improve chances of retaining vision. The present study aimed to demonstrate the common lens-related ocular emergencies in dogs and evaluate the short-term outcomes after treatment of these cases. Sixty dogs (90 eyes) of different breeds were presented with unilateral (30 eyes, OD = 18, OS = 12) and bilateral (60 eyes) ocular abnormalities related to crystalline lens injury. Clinical, ultrasonographic, and laboratory examinations were achieved. Different treatment protocols were conducted after complete ophthalmic examination and the associated clinical outcomes were evaluated. Results Mean (± SD) age of dogs at initial evaluation was 3.65 (± 2.4) years (range, 1˗12 years). Lens luxation and subluxation were diagnosed in 45 eyes (25 with anterior lens luxation, 15 with subluxation, and 5 with posterior lens luxation). Lens-induced anterior uveitis without glaucoma (n = 25 eyes), uveitic glaucoma (n = 15 eyes), and lens capsule disruption (n = 5 eyes) were also diagnosed. The vision was lost in all 5 eyes with posterior lens luxation (100%), 18/25 eyes with anterior lens luxation (72%), and 5/15 eyes with lens subluxation (33.3%). Vision impairment was also identified in 10/25 eyes (40%) with unresponsive lens-induced anterior uveitis and in 5/5 eyes (100%) with traumatic rupture of the anterior lens capsule. Conclusion Crystalline lens injury can cause a wide variety of ocular emergencies that may result in blindness. Early diagnosis and appropriate treatment are crucial for handling lens-related emergencies in dogs.

CircHIPK3 knockdown suppresses E2F3 expression to inhibit the viability and promote the apoptosis of lens epithelial cells in age-related cataract by sponging miR-499a-5p

IntroductionCircular RNA (circRNA) is considered to be a vital regulator of disease progression, including age-related cataract (ARC). However, the molecular mechanism of circHIPK3 in ARC progression has not been fully elucidated.Material and methodsThe expression levels of circHIPK3, miR-499a-5p and E2F transcription factor 3 (E2F3) were measured by quantitative real-time PCR. Cell counting kit 8 assay and flow cytometry were performed to detect cell viability and apoptosis, respectively. Western blot analysis was employed to test the protein levels of apoptosis-related markers and E2F3. Biotin-labeled RNA pull-down assay was used to select miRNAs that could be targeted by circHIPK3, and dual-luciferase reporter assay was performed to confirm the interaction between miR-499a-5p and circHIPK3 or E2F3.ResultsCircHIPK3 is a stable circRNA that is significantly under-expressed in the anterior lens capsule tissues of ARC patients. Knockdown of circHIPK3 suppressed SRA01/04 cell viability and accelerated apoptosis. Moreover, miR-499a-5p could be targeted by circHIPK3, and its inhibitor reversed the effect of circHIPK3 silencing on cell viability and apoptosis. Furthermore, E2F3 was a target of miR-499a-5p, and its overexpression reversed the effect of miR-499a-5p on the viability and apoptosis of SRA01/04 cells. In addition, circHIPK3 positively regulated E2F3 expression by sponging miR-499a-5p.ConclusionsCircHIPK3 knockdown inhibited viability and enhanced apoptosis of lens epithelial cells to promote ARC progression by regulating miR-499a-5p/E2F3 axis.

Metformin Reduced Collagen Deposition and Contractility, but Increased Collagen Degradation in in vitro Posterior Capsule Opacification Model

BACKGROUND: Posterior capsule opacification (PCO) often occurs after cataract surgery. Metformin has been known to have an ability to inhibit fibrosis. This study aimed to investigate the effects of metformin on cell contractility, collagen deposition and degradation in human lens epithelial cells (HLEC) of cataract patients.METHODS: HLEC were isolated from the anterior lens capsule of patients undergoing cataract surgery. The HLEC culture was carried out using explant culture technique. The in vitro PCO model was created by scratching technique on HLEC cultures. The treatment groups were given 0.1, 0.5 and 1 mM metformin, respectively, while the control group were given 10% fetal bovine serum (FBS). On the 7th day after scratching technique, the collagen deposition, collagen degradation and cell contractility were evaluated.RESULTS: Collagen deposition in HLEC was significantly reduced after given 0.1 mM, 0.5 mM and 1 mM metformin (17.92±6.16 mg/mL, 12.92±4.31 mg/mL, 11.25±5.30 mg/mL, respectively), compared to the control group (31.46±7.52 μg/mL, p=0.002). Collagen degradation significantly was increased in the 0.1 mM, 0.5 mM and 1 mM metformin groups (4.77±9.27 mg/mL, 6.59±1.16 mg/mL, 6.35±1.90 mg/mL, respectively) compared to the control group (2.21±2.78 μg/mL, p=0.002). While, collagen contractility in HLEC was significantly reduced in 0.1mM, 0.5mM and 1 mM metformin groups (16.39±3.89%, 13.89±2.59%, 11.93±2.44%, respectively), compared to the control group (44.25±4.95%, p=0.000).CONCLUSION: Metformin reduced collagen deposition and contractility, but increased collagen degradation in HLEC of cataract patients through mechanism of extracellular matrix remodeling.KEYWORDS: metformin, human lens epithelial cell, fibrosis

UV Effect on Human Anterior Lens Capsule Macro-Molecular Composition Studied by Synchrotron-Based FTIR Micro-Spectroscopy

Ultraviolet (UV) irradiation is an important risk factor in cataractogenesis. Lens epithelial cells (LECs), which are a highly metabolically active part of the lens, play an important role in UV-induced cataractogenesis. The purpose of this study was to characterize cell compounds such as nucleic acids, proteins, and lipids in human UV C-irradiated anterior lens capsules (LCs) with LECs, as well as to compare them with the control, non-irradiated LCs of patients without cataract, by using synchrotron radiation-based Fourier transform infrared (SR-FTIR) micro-spectroscopy. In order to understand the effect of the UV C on the LC bio-macromolecules in a context of cataractogenesis, we used the SR-FTIR micro-spectroscopy setup installed on the beamline MIRAS at the Spanish synchrotron light source ALBA, where measurements were set to achieve a single-cell resolution with high spectral stability and high photon flux. UV C irradiation of LCs resulted in a significant effect on protein conformation with protein formation of intramolecular parallel β-sheet structure, lower phosphate and carboxyl bands in fatty acids and amino acids, and oxidative stress markers with significant increase of lipid peroxidation and diminishment of the asymmetric CH3 band.