Zonula Research Articles

Finite Element Analysis of Mechanical Ocular Sequelae from Badminton Shuttlecock Projectile Impact

PurposeWith the growing popularity of badminton worldwide, the incidence of badminton-related ocular injuries is expected to rise. The high velocity of shuttlecocks renders ocular traumas particularly devastating, especially with the possibility of permanent vision loss. This study investigated the mechanism behind ocular complications though simulation analyses of mechanical stresses and pressures upon shuttlecock impact. DesignComputational simulation study ParticipantsNone MethodsA 3-dimensional human eye model was reconstructed based on the physiological and biomechanical properties of various ocular tissues. FEA simulations involved a frontal collision with a shuttlecock projectile at 128.7 km/h (80 mph). Intraocular pressure changes and tissue stress were mapped and quantified in the following ocular structures: the limbus, ciliary body, zonular fibers, ora serrata, retina, and optic nerve head. Main Outcome MeasuresIntraocular pressure and tissue stress ResultsUpon shuttlecock impact, compressive force was transferred to the anterior pole of the cornea, propagating posteriorly to the optic nerve head. Deflection of forces anteriorly contributed to refractory oscillations of compressive and tensile stress of ocular tissue. Initial impact led to a momentary (< 1 ms) spike in intraocular pressure 5.66 MPa (42.5 x 103 mmHg) that radially distributed for a very brief instance (< 1 ms) of pressure at the trabecular meshwork of the iridocorneal angle of 1.25 MPa (9.4 x 103 mmHg). The lens had a maximal posterior displacement of 1.5 mm with peak zonular fiber tensile strain of 52%. The limbus, ciliary body, and ora serrata had a peak tensile stress of 5.16 MPa, 1.90 MPa, and 0.62 MPa, respectively. Compressive force from the sclera concentrated at the optic nerve head for a peak stress of 5.97 MPa while peak pressure from vitreous humor was 7.99 MPa. ConclusionShuttlecock impact led to a very brief, substantial rise in pressure and stress significant for tissue damage and subsequent complications, such as secondary glaucoma, angle recession, lens subluxation, hyphema, or retinal dialysis. Our findings offer valuable mechanistic insights into how ocular structures are affected by shuttlecock projectile impact to inform clinical assessments and treatment strategies, while highlighting the importance of protective eyewear in racket sports.

Examination of Vitreolenticular Interface in Relation to Different Phacoemulsification Parameters in Early and Late Postoperative Period.

Background: The surgical parameters of phacoemulsification can significantly impact the behavior of the anterior hyaloid membrane (AHM). Methods: In this prospective study, anterior segment optical coherence tomography was used to examine the attachment or detachment of the AHM of 82 eyes after uneventful phacoemulsification preoperatively and postoperatively over 1 year. The impacts of the capsulorhexis' size, number of hydrodissections, nuclear sclerosis grade, cumulative dissipated energy (CDE), ultrasonic time, total surgical time, weakness of zonular fibers, presence of lens materials in Berger's space (LM-BS), and fluid usage were investigated in relation to the behavior of the AHM. Results: A significant linear trend regarding anterior vitreous detachment (AVD) was observed in the presence of zonular weakness and high CDE at all postoperative times (p ≤ 0.024 and p ≤ 0.005, respectively). Similarly, AVD was observed at 1-month, 3-month, and 1-year follow-ups in cases of high nuclear sclerosis grades (p ≤ 0.044) and high fluid usage (p ≤ 0.021). A significant correlation was observed in the group of LM-BS as the zonular weakness value increased (OR: 0.085; 95% CI: 0.017 to 0.420; p = 0.002), and the fluid usage was also significantly higher (OR: 1.049; 95% CI: 1.003-1.096; p = 0.037). Conclusions: Zonular weakness, high CDE, a hard nucleus, and high fluid usage are risk factors for postoperative AVD.

The Effect of the Zonular Fiber Angle of Insertion on Accommodation.

Purpose: With age, there is an anterior shift of the ciliary body in the eye, which alters the angle of zonular insertion in older eyes compared with younger eyes. This study aims to simulate lens accommodation with different zonular angles to consider the influence of zonular position on lens accommodative capacity. Methods: Models were constructed based on lenses aged 11, 29, and 45 years using a 2D axisymmetric structure that included a capsule, cortex, nucleus, and zonular fibers. The different zonular fibers were simulated by changing the position of the point where the zonular fibers connect to the ciliary body. The effect of the different zonular fiber insertion angles on the model shape and optical power was analyzed. Results: The models show that smaller angles made by zonular fibers to the surface of the lens lead to larger optical power changes with simulated stretching. When the models were stretched, and when varying the zonule angles, the optical power of the 11-, 29-, and 45-year-old models changed up to 0.17 D, 0.24 D, and 0.30 D, respectively. The effect of zonular angles on the anterior radius of curvature of the anterior surface varied by 0.29 mm, 0.23 mm, and 0.25 mm for the 11-, 29-, and 45-year-old models, respectively. Conclusions: Larger zonular fiber insertion angles cause smaller deformation and less accommodative change, while parallel zonules induce the largest change in lens shape.

Zonular fibre Insertion-to-Limbus Distance (ZLD): normative data to assess lens position and diagnose ectopia lentis

PurposeSubluxation of the crystalline lens (Ectopia Lentis, EL) can lead to significant visual impairment and serves as a diagnostic criterion for genetic disorders such as the Marfan syndrome. There is no established criterion to diagnose and quantify EL. We prospectively investigated the distance between the zonular fibre insertion and the limbus (ZLD) in healthy subjects as a parameter to assess the position of the lens, quantify EL and provide normative data.MethodsThis prospective, observational, cross-sectional study includes one-hundred-fifty eyes of 150 healthy participants (mean age 28 years, range 4–68). Pupils were dilated with tropicamide 0.5% and phenylephrine 2.5% eyedrops. ZLD was measured in mydriasis at the slit lamp as the distance between the most central visible insertions of the zonular fibres on the lens surface and the corneoscleral limbus. Vertical pupil diameter (PD) and refractive error were recorded. If zonular fibre insertions were not visible, the distance between limbus and the pupillary margin was recorded as ZLD.Results145 right and 5 left eyes were examined. 93% of study subjects were Caucasian, 7% were Asian. In eyes with visible zonular fibre insertions (n = 76 eyes), ZLD was 1.30 ± 0.28 mm (mean ± SD, range 0.7–2.1) and PD was 8.79 ± 0.57 mm (7.5–9.8). In the remaining 74 eyes, ZLD was 1.38 ± 0.28 mm (0.7–2.1), and PD was 8.13 ± 0.58 mm (6.7–9.4). For all eyes, ZLD was 1.34 ± 0.29 mm (0.7–2.1), and PD was 8.47 ± 0.66 mm (6.7–9.8). Refractive error and sex did not significantly affect ZLD. Smaller PD and older age were associated with larger ZLD (P < 0.001 and P = 0.036, respectively).ConclusionAverage ZLD was 1.34 mm in eyes of healthy subjects. Older age correlated with larger ZLD. These normative data will aid in diagnosing and quantifying EL.

Investigation of crystalline lens overshooting: ex vivo experiment and optomechanical simulation results.

Introduction: Crystalline lens overshooting refers to a situation in which the lens momentarily shifts too much from its typical location immediately after stopping the rotational movement of the eye globe. This movement can be observed using an optical technique called Purkinje imaging. Methods: In this work, an experimental setup was designed to reproduce this effect ex vivo using a fresh porcine eye. The sample was rotated 90° around its centroid using a high-velocity rotation stage, and the Purkinje image sequences were recorded, allowing us to quantify the overshooting effect. The numerical part of the study consisted of developing a computational model of the eye, based on the finite element method, that allowed us to understand the biomechanical behavior of the different tissues in this dynamic scenario. A 2D fluid-structure interaction model of the porcine eye globe, considering both the solid parts and humors, was created to reproduce the experimental outcomes. Results: Outputs of the simulation were analyzed using an optical simulation software package to assess whether the mechanical model behaves optically like the real ex vivo eye. The simulation predicted the experimental results by carefully adjusting the mechanical properties of the zonular fibers and the damping factor. Conclusion: This study effectively demonstrates the importance of characterizing the dynamic mechanical properties of the eye tissues to properly comprehend and predict the overshooting effect.

Zonulopathy and its Relation to Primary Angle Closure Disease: A Narrative Review.

This paper aims to discuss the anatomical features of zonule fibers that centers the lens in the eye and summaries the relationship between zonulopathy and PACD.

Successful Management of Cataract in Patient With Long Anterior Zonules and Small Pupil :A Rare Case

Introduction : Long anterior zonules (LAZ) are rare disease with prevalence was 1–2%, characterized by zonular fibers that extend centrally leading to a small zonule-free zone (ZFZ), which raises the risk of complications during zonular cutting while continuous curvilinear capsulorhexis (CCC). This leads to two options whether to perform phacoemulsification through a small CCC within the small ZFZ or an adequately sized CCC. The objective of this study was to report challenging management of phacoemulsification surgery with LAZ eyes with small pupil&#x0D; Case Illustration : A 62 y.o female had visual acuity(VA) 0.7(logMAR) due to corticonuclear cataract in left eye. She had history complicated cataract surgery with secondary sulcus fixated IOL in her fellow eye. The IOP was normal, no phacodenesis and pseudoexfoliative material observed in left eye. The posterior segment was normal. The left eye observed otherwise normal in initial examination. Intraoperatively, after viscomidriasis technique the ZFZ identified in the area of 2.0-2.5 mm from central. Five millimeter CCC can be achieved in the central area and phacoemulsification with the help of CTR (Capsular Tension Ring) safely performed and one piece IOL was implanted in the bag.&#x0D; Discussion : On the first postoperative day, VA was improves to 0.4(logMAR), IOL central and clear corneal with minimal inflammation. One week after surgery, the VA 0.3(logMAR) and no sign of IOL decenteration.&#x0D; Conclusion : Phacoemulsification in eyes with LAZs can be safely performed with CTR through an adequately sized CCC without significant complications. A combination of early recognising high-risk eye, proficient skills, and surgical instruments can improve outcome.

Structural and functional features of the eye in Marfan syndrome. Report 2. Changes in the anatomical complex of the lens

This study assesses the state of the anatomical complex of the lens in MS using UBM. The study was carried out on clinical material previously used by us to analyze changes in the fibrous membrane of the eye in MS. At the first stage, the main (19 patients with MS, 38 eyes) and the control (24 patients with myopia, 48 eyes) groups were formed for comparative evaluation. The formed groups were standardized according to the age of the patients and the axial length of the eye. At the second stage, patients with MS were divided into subgroups depending on the absence or presence of biomicroscopic signs of ectopia lentis (22 and 16 eyes, respectively). For UBM, an ultrasound linear sensor with a scanning frequency of 50 MHz was used (Aviso device, Quantel Medical, France). Various biometric UBM indicators were determined: lens thickness, diameter of the lens, lens-axial length factor, iris-lens angle, iris-lens contact distance, posterior chamber depth, length of the fibers of ciliary zonule, thickness of the ciliary body, sclera-ciliary process angle. There are changes in the anatomical complex of the lens as a whole in MS (in the lens itself, the ciliary zonule, and the ciliary body), which are characterized by an increase in lens thickness and a decrease in the diameter of the lens, an increase in the length of the fibers of the ciliary zonule and a decrease in the thickness of the ciliary body. At the same time, the displacement of the lens detected by optical biomicroscopy (ectopia lentis) can be considered as an advanced stage of changes in the anatomical complex of the lens. UBM provides the possibility of full-fledged visualization of all components of the anatomical complex of the lens in terms of both diagnostics, and monitoring of changes in MS. The question of the advisability of including this method in the algorithm for diagnosing ocular manifestations in order to verify the MS remains open. Possible obstacles may be, on the one hand, related to the need for special and expensive equipment, and on the other hand, the absence of a generally accepted «normal» values of UBM indicators of the anatomical complex of the lens.

Retinitis Pigmentosa with Bilateral Ectopia Lentis

Retinitis pigmentosa (RP), a degenerative disorder characterized by a diverse array of ocular and systemic manifestations, was initially reported in 1857. Despite over a century of research, zonular weakness in RP still remains unsolved. We report a late presentation of bilateral inferior subluxation of lens, with visible zonular fibres. The patient exhibited no systemic abnormalities suggestive of a syndromic presentation. This appears to be a rare instance of bilateral concurrent spontaneous ectopia lentis (EL) associated with RP, with no syndromic association. It serves as a wake-up call for urgent need of further research in understanding the aetiology of RP.

A novel ADAMTSL4 compound heterozygous mutation in isolated ectopia lentis: a case report and review of the literature

BackgroundCongenital ectopia lentis is characterized by dislocation of the lens caused by partial or complete abnormalities in the zonular fibers. It can be caused by either systemic diseases or isolated ocular diseases. Gene detection techniques can provide valuable information when an etiological diagnosis is challenging. Herein, we report the case of a six-year-old girl with a confirmed diagnosis of isolated ectopia lentis caused by a compound heterozygous ADAMTSL4 gene mutation.Case presentationThe patient was a 6-year-old Chinese Han girl with strabismus in the right eye. Slit lamp examination revealed that the lens in the right eye was opacified and dislocated, without an ectopic pupil. Gene detection demonstrated the presence of a compound heterozygous mutation in the ADAMTSL4 gene [c. 2270dupG (p.Gly758Trpfs *59) and c. 2110A > G (p.Ser704Gly)], and the diagnosis of isolated ectopia lentis was confirmed. She underwent lens extraction, and a sutured scleral-fixated posterior chamber intraocular lens (IOL) was placed in the right eye. The best-corrected visual acuity was 0.1 one month postoperatively.ConclusionGene detection plays a crucial role in diagnosing disorders with similar symptoms, such as isolated ectopia lentis and Marfan syndrome. In this study, we used whole exons sequencing to diagnose isolated ectopia lentis and identified the variant c.2110A > G (p.Ser704Gly), which may be associated with the development of ectopia lentis and early-onset cataract in the patient. These pathogenic gene mutations have significant implications for the genetic diagnosis of congenital ectopia lentis, treatment, surveillance, and hereditary and prenatal counseling for the patient and their family members.

Оценка метода профилактики девиации ирригационного потока при факоэмульсификации с использованием дисперсивного вискоэластика (Вискоблок) в аспекте состояния витреолентикулярного интерфейса

Purpose. Evaluate state of the vitreolenticular interface before surgery, during phacoemulsification of cataract, and in the early postoperative period. To assess the effectiveness of «Viscoblock» method application during phacoemulsification to prevent intraoperative irrigation fluid misdirection syndrome by blocking the penetration of irrigation fluid through the zonular fibers through injecting dispersive ophthalmic viscosurgical device behind the iris. Material and methods. We operated 49 patients (50 eyes) diagnosed with age-related cataracts. All patients were divided into two groups. In the first group, we performed phacoemulsification with hydrophobic intraocular lens (IOL) implantation and application of the «Viscoblock» method. This group included 24 patients. In the second group, we performed phacoemulsification with hydrophobic IOL implantation using standard technique, it included 25 patients. All patients underwent standard ophthalmological examination and specific additional ones: ultrasound biomicroscopy – UBM Aviso (Quantel Medical, France); spectral optical coherence tomography OCT (Solix, Optovue, USA). Surgical treatment was performed under the control of an operating microscope equipped with intraoperative OCT (Lumera Rescan 700, Carl Zeiss, Germany). Results. According to preoperative diagnostics and it's UBM data, all patients in the first and second groups showed abnormalities in lens zonular fibers. According to OCT data before the surgery, no cases of anterior hyaloid membrane (AHM) detachment were detected. During the surgery, AHM detachment was observed in 24% of cases in first group and in 56% of cases in second group. Intraoperative iris prolapses occurred in 8% of cases only in the first group. Posterior capsule rupture was observed in only 1 patient in second group. Conclusion. Our technique, «Viscoblock», allows us to limit the penetration of irrigation fluid through the Zonula ciliaris in 76% of cases. However, it should be noted that the method does not provide complete prevention of AHM detachment, as it may already exist in some patients. Additionally, we cannot exclude partial washout of viscoelastic substance during the surgery, which can reduce the tamponade effect. Key words: vitreo-lenticular interface, Berger's space, intraoperative fluid misdirection syndrome, optical coherence tomography, ultrasound biomicroscopy, «Viscoblock», cataract, lens zonular fibers, vitreous body, posterior lens capsule, anterior hyaloid membrane, intraocular lens

Spontaneous lens luxation in an 88-year old female with exfoliative glaucoma

Spontaneous lens dislocation is a result of disruption of the ciliary body zonules and may develop because of damage of the zonule fibers that holds the lens in place. Lens luxation may occur spontaneously in association with ocular or systemic disease or can follow trauma. In exfoliative glaucoma, exfoliation material affects the zonular system, creating fragility and weakening of the zonular support leading to subsequent laxity of the lens [1-4]. We report herein an uncommon case of unilateral spontaneous lens luxation in a patient with exfoliative glaucoma.

The major influence of anterior and equatorial zonular fibres on the far-to-near accommodation revealed by a 3D pre-stressed model of the anterior eye

PurposeTo explore the synergistic function of the ligaments in eye, the zonular fibres, that mediate change in eye lens shape to allow for focussing over different distances. MethodsA set of 3D Finite Element models of the anterior eye together with a custom developed pre-stress modelling approach was proposed to simulate vision for distant objects (the unaccommodated state) to vision for near objects (accommodation). One of the five zonular groups was cut off in sequence creating five models with different zonular arrangements, the contribution of each zonular group was analysed by comparing results of each specific zonular-cut model with those from the all-zonules model in terms of lens shape and zonular tensions. ResultsIn the all-zonular model, the anterior and equatorial zonules carry the highest tensions. In the anterior zonular-cut model, the equatorial zonular tension increases while the posterior zonular tension decreases, resulting in an increase in the change in Central Optical Power (COP). In the equatorial zonular-cut model, both the anterior and posterior zonular tensions increase, causing a decreasing change in COP. The change in COP decreases only slightly in the other models. For vitreous zonular-cut models, little change was seen in either the zonular tension or the change in COP. ConclusionsThe anterior and the equatorial zonular fibres have the major influence on the change in lens optical power, with the anterior zonules having a negative effect and the equatorial zonules contributing a positive effect. The contribution to variations in optical power by the equatorial zonules is much larger than by the posterior zonules.

Результаты смешанной цилиокапсулярной фиксации трехчастной ИОЛ при факоэмульсификации у пациентов с несостоятельностью связочного аппарата хрусталика

Purpose. To evaluate clinical results of mixed ciliary-capsular fixation of a three-piece IOL in combination with the intracapsular ring's implantation during phacoemulsification in patients' zonular weakness caused by pseudoexfoliative (PEX) syndrome. Material and methods. This study included 78 patients (86 eyes) with complicated cataract and PEX syndrome associated with zonular weakness and natural lens instability. The average age of the patients was 74.3±9.3 years. Phacoemulsification was performed in a standard technique and followed by ciliary-capsular fixation of a three- piece IOL in all cases. Preoperative and postoperative follow up period lasted from 1st day until 10 months postop. It included biomicroscopy, visual acuity measurement, keratometry, tonometry, ultrasonic biomicroscopy, optical coherence tomography of the posterior segment of the eye. Results. At the 2nd day postop (86 cases) UCVA and BCVA were 0.46±0.29 and 0.58±0.27 respectively, IOP was 16.48±2.81 mm Hg; at 10 months postop (38 cases) UCVA and BCVA – 0.54±0.31 and 0.79±0.28, IOP – 15.34±3.71 mm Hg. The average deviation of the predicted refraction at the 2 days after surgery was –0.29±0.77 D with no significant change after 10 months. Efficiency ratio at 10 months postop was 193, the safety factor was 285. This type of IOL fixation didn't lead to an increase in IOP, development of chronic inflammation such as iridocyclitis or any other comorbidity. All IOLs were stable position regardless of the status of the zonular fibers. Conclusion. As a result of a preliminary study, it was found that mixed ciliary-capsular fixation of a three-piece IOL provides its stable position, high clinical and functional results in the early and late postoperative period after phacoemulsification in patients with pseudoexfoliative syndrome and failure of the lenticular ligamentous-capsular system. Key words: pseudoexfoliative syndrome, zonular weakness, intraocular lens, ciliary-capsular fixation, lens subluxation, myopic shift

Drug-Induced Myopia: Pathogenesis, Diagnosis, and Treatment

Myopia is one of the leading causes of visual impairment. Systemic agents cause myopia by three main mechanisms. It is an increase in the refractive power of the lens with ciliary muscle spasm, an increase in the refractive power of the lens with water retention, and finally the anterior displacement of the lens with swelling of the ciliary processes. Idiosyncratic reaction in uveal tissue is dose-independent and is the main pathology. In general, as a result of ciliochoroidal effusion, the ciliary body-lens-iris block is displaced anteriorly, and myopia occurs with the relaxation of the zonular fibers. Many drugs have been reported to cause this condition, and mostly sulfa derivatives cause myopia. Acetazolamide, topiramate, indapamide, sulfasalazine, methazolamide, co-trimaxazole, ethoxolamide, hydrochlorothiazide, chlorthalidone, psychotropic agents are in this group. In this review, the drugs that cause myopia and their pathological mechanisms and treatments will be explained.

The ciliary zonules provide a pathway for immune cells to populate the avascular lens during eye development.

The eye is an immune-privileged site, with both vasculature and lymphatics absent from the central light path. Unique adaptations have made it possible for immune cells to be recruited to this region of the eye in response to ocular injuries and pathogenic insults. The induction of such immune responses is typically activated by tissue resident immune cells, considered the sentinels of the immune system. We discovered that, despite the absence of an embedded vasculature, the embryonic lens becomes populated by resident immune cells. The paths by which they travel to the lens during development were not known. However, our previous studies show that in response to corneal wounding immune cells travel to the lens from the vascular-rich ciliary body across the zonules that link these two tissues. We now examined whether the zonule fibers provide a path for immune cells to the embryonic lens, and the zonule-associated matrix molecules that could promote immune cell migration. The vitreous also was examined as a potential source of lens resident immune cells. This matrix-rich site in the posterior of the eye harbors hyalocytes, an immune cell type with macrophage-like properties. We found that both the zonules and the vitreous of the embryonic eye contained fibrillin-2-based networks and that migration-promoting matrix proteins like fibronectin and tenascin-C were linked to these fibrils. Immune cells were seen emerging from the ciliary body, migrating along the ciliary zonules to the lens, and invading through the lens capsule at its equator. This is just adjacent to where immune cells take up residence in the embryonic lens. In contrast, the immune cells of the vitreous were not detected in the region of the lens. These results strongly suggest that the ciliary zonules are a primary path of immune cell delivery to the developing lens.

Effect of phacoemulsification on the Berger space

Objective: To investigate the effect of phacoemulsification on the Berger space (BS). Methods: A prospective cohort study. Patients with cataract who underwent phacoemulsification and intraocular lens implantation in the Department of Ophthalmology, Affiliated Hospital of Nantong University from May 2021 to October 2021 were enrolled. The BS was observed by slit-lamp microscopy and anterior segment optical coherence tomography (AS-OCT) before and 1 month after operation. Intraoperative optical coherence tomography with a 25G optical fiber was performed to observe the BS. The number of eyes with the BS and materials in the BS (MIB) detected perioperatively was counted, and the width of the BS was measured. Statistical analysis was carried out by the Chi-square test, generalized estimating equations, Mann-Whitney U test and binary logistic regression analysis. Results: A total of 119 patients (119 eyes) were included [44 males, 75 females; mean age, (65±12) years]. Preoperatively, the BS was identified in only 4 eyes (3.4%), and no MIB was found. Intraoperatively, the BS was identified in 47 eyes (39.5%), and the MIB was observed in 20 eyes (16.8%). At one month postoperatively, the BS was identified in 33 eyes (27.7%), of which 16 eyes (13.4%) still had MIB. There were significant differences in the detection rates of the BS and MIB between intraoperative and preoperative groups (both P<0.001). The difference in the detection rate of the BS postoperatively compared to intraoperatively was statistically significant (P=0.001), while the difference in the detection rate of MIB was not statistically significant (P>0.05). The intraoperative and postoperative width of the BS [M (Q1, Q3)] was 160.3 (61.6, 273.1) μm and 106.8 (0, 259.4) μm, respectively, and the difference was statistically significant (Z=-2.28, P=0.023). In addition, the detection rate of the BS and MIB in patients with a high risk of zonular fiber weakness [60.7% (17/28) and 42.9% (12/28)] was significantly higher than that in patients without this risk factor [33.0% (30/91) and 8.8% (8/91)] (χ²=6.90, P=0.009; P<0.001). In the multivariable model, weakness of zonular fibers (OR=0.214, 95%CI: 0.081 to 0.561) and higher cumulative dissipated energy (OR=1.255, 95%CI: 1.047 to 1.504) were the main risk factors for structural changes of the BS intraoperatively. Conclusion: Phacoemulsification can damage the normal anatomical structure of the BS, resulting in intraoperative entrance of fluid and particulates to the BS.

3D Modeling of the Crystalline Lens Complex under Pseudoexfoliation.

Pseudoexfoliation, one of the most frequent crystalline lens complex disorders, is prevalent in up to 30% of individuals older than 60 years old. This disease can lead to severe conditions, such as subluxation or dislocation of the lens, due to the weakening of the zonules. The goal for the present study was to understand the relevant biomechanical features that can lead to the worsening of an individual’s visual capacity under pseudoexfoliation. To this end, finite element models based on a 62-year-old lens complex were developed, composed by the capsular bag, cortex, nucleus, anterior, equatorial, and posterior zonular fibers. Healthy and pseudoexfoliative conditions were simulated, varying the location of the zonulopathy (inferior/superior) and the degenerated layer. The accommodative capacity of the models with inferior dialysis of the zonular fibers was, on average, 4.7% greater than for the cases with superior dialysis. If the three sets of zonules were disrupted, this discrepancy increased to 14.9%. The present work provides relevant data to be further analyzed in clinical scenarios, as these models (and their future extension to a wider age range) can help in identifying the most influential regions for the reduction of the visual capacity of the lens.

Spontaneaous dislocation of the crystalline lens in the anterior chamber in a patient with pseudoexfoliation syndrome

Pseudoexfoliation syndrome (PEX) is a systemic disorder of the extracellular matrix that presents primarily via its characteristic ocular manifestations [1]. Typically, white fibrillary residue on the anterior lens capsule and pupillary margin is observed, as are pupillary transillumination defects and pigmentation of the trabecular meshwork [2]. Zonular weakness can be attributed to the deposition of pseudoexfoliative material on the zonular fibers and ciliary processes, resulting in a proteolytic disintegration of the zonule that can lead to spontaneous fragmentation [2]. We report a case of a dislocation of the hole crystalline lens in the anterior chamber in a patient with pseudoexfoliation syndrome.

Intraoperative complication rates in cataract surgery performed by resident trainees and staff surgeons in a tertiary eyecare center in Hungary.

To compare the incidence of intraoperative complications during primary phacoemulsification (phaco) surgery between resident surgeons (residents) and staff surgeons (specialists) and to objectively determine the difficulty of stages in phaco surgery. This retrospective study included cases of phaco cataract surgery performed between January and December 2019. There were no exclusion criteria. For each patient, demographics, clinical history, case complexity, type of surgeon, and operative details were reviewed. Primary outcomes included intraoperative complication rates and the objective measure of difficulty in the steps of the surgery performed by residents and specialists. A total of 3272 cases were included; 7.4% (n=241) of cases were performed by residents. The overall complication rate was 5.4% (n=177). The intraoperative complication rate was significantly higher (P<0.001) in residents (n=33, 13.7%) than in specialists (n=144, 4.8%). The most frequent complications were posterior capsule tear (n=85, 2.6%), anterior capsule tear (n=50, 1.53%), zonular fiber loss (n=45, 1.38%), and dropped nucleus (n=15, 0.46%). Objectively, the most difficult steps during surgery were phaco in 66 (60.0%), capsulorhexis in 21 (19.1%), irrigation/aspiration in 13 (11.8%), hydrodissection in 9 (8.2%), and intraocular lens (IOL) implantation in 1 (0.9%) case. Intraoperative complication rates are higher in residents than in specialists. The order of objective difficulty in phaco surgery steps is in line with the subjective findings of other surveys, revealing that the most challenging parts of phaco surgery are phaco and capsulorhexis.