BLM can regulate cataract progression by influencing cell vitality and apoptosis.

Age-related cataract (ARC) is the most common cause of severe visual impairment and blindness. The precise mechanisms of ARC are not completely understood, but it is well accepted that oxidative damage plays an important role in the disease pathogenesis. BLM, the key enzyme of the double-strand break repair (DSBR) pathway, is part of a family of DNA unwinding enzymes and has a crucial role in multiple steps of the DNA recombination, replication and repair processes. We have recently shown that BLM-rs1063147 is initially associated with nuclear ARC in a cross-section study. Therefore, we wanted to study the effects of BLM on ARC progression. In ARC patients, BLM transcription in lens capsules was decreased, so did the BLM protein, and after UVB irradiation, BLM mRNA and protein levels were increased in SRA01/04 cells. Upon silencing BLM in SRA01/04 cells and rat lens, cell vitality and apoptosis were altered, and the rat lens opacification was considerable. In conclusion, BLM can regulate cataract progression by influencing cell vitality and apoptosis.

Transient bilateral cataract during intensive glucose control: a case report.

BACKGROUND: Cataracts are generally known to occur in hyperglycemic conditions in diabetic patients. In this case, cataract occurred in the course of glucose level control in a patient who had been in a hyperglycemic state. CASE PRESENTATION: A 42-year-old Korean man who had uncontrolled diabetes for more than a year presented with bilateral posterior subcapsular cataracts, which developed within days of initiating antihyperglycemic therapy. With control of his serum glucose level for several weeks, the cataracts regressed. CONCLUSIONS: Transient cataracts can develop during the hypoglycemic state; prompt surgery should be deferred.

Anterior chamber depth and refractive change in late postoperative capsular bag distension syndrome: a retrospective analysis.

PURPOSE: To assess the characteristic findings and effects of laser capsulotomy in patients with late postoperative capsular bag distension syndrome (CBDS). METHODS: Twenty patients diagnosed with late postoperative CBDS between July 2010 and August 2013 were retrospectively reviewed. Before and 1 week after capsulotomy, changes in the anterior chamber depth (ACD) were assessed using ultrasound biomicroscopy. Changes in the refractive status and uncorrected visual acuity (UCVA) were also measured 1 week and 1 month after capsulotomy. For patients who received bilateral cataract surgery, preoperative ACD and axial length measured by IOLMaster were compared between the two eyes. RESULTS: Twenty-two eyes from 20 patients who had undergone laser capsulotomy showed a mean UCVA improvement of 0.27 ± 0.24 logMAR (range, 0.00-0.90). ACD was increased by an average of +0.04 mm (95% confidence interval, +0.01 to +0.06 mm, p = 0.034), equivalent to predicted refractive change of +0.10 D. The discrepancy between actual (+1.33 D) and predicted refractive change after capsulotomy suggests that refractive change may not be generated from IOL displacement in late postoperative CBDS. Preoperative ACD was deeper in the eye with late postoperative CBDS in all bilaterally pseudophakic patients (mean, 3.68 mm vs. 3.44 mm in the fellow eye, p = 0.068). CONCLUSIONS: Late postoperative CBDS showed refractive changes that were resolved successfully after laser capsulotomy. The convex lens effects of opalescent material in the distended capsular bag may play a major role in myopic shift. A larger preoperative ACD is possibly associated with the development of late postoperative CBDS.

Defining the ideal femtosecond laser capsulotomy.

PURPOSE: We define the ideal anterior capsulotomy through consideration of capsular histology and biomechanics. Desirable qualities include preventing posterior capsular opacification (PCO), maintaining effective lens position (ELP) and optimising capsular strength. METHODS: Laboratory study of capsular biomechanics and literature review of histology and published clinical results. RESULTS: Parameters of ideal capsulotomy construction include complete overlap of the intraocular lens to prevent PCO, centration on the clinical approximation of the optical axis of the lens to ensure concentricity with the capsule equator, and maximal capsular thickness at the capsulotomy edge to maintain integrity. CONCLUSIONS: Constructing the capsulotomy centred on the clinical approximation of the optical axis of the lens with diameter 5.25 mm optimises prevention of PCO, consistency of ELP and capsular strength.

Effect of heparin coating of a foldable intraocular lens on inflammation and capsular bag performance after cataract surgery.

PURPOSE: To evaluate the effect of a heparin-coated foldable intraocular lens (IOL) on postoperative flare in high-risk patients. SETTING: Vienna Institute for Research in Ocular Surgery, Department of Ophthalmology, Hanusch Hospital, Vienna, Austria. DESIGN: Randomized clinical trial. METHODS: This study included patients with diabetes mellitus (DM), pseudoexfoliation syndrome (PXF), or both scheduled for cataract surgery in both eyes. One eye received a coated IOL (Polylens EC-1YH PAL) and the other eye, an uncoated control IOL (Polylens EC-1Y PAL). Aqueous flare measurements were taken using a laser flare meter (FM-600, Kowa) preoperatively and 1 hour, 1 day, 3 weeks, and 3 months postoperatively. Visual acuity and anterior (ACO) and posterior (PCO) capsule opacification were assessed, and IOL centration and tilt were measured with a Purkinje meter. RESULTS: Eighty eyes of 40 patients were included in the study; 64 eyes of 32 patients completed the study. The mean flare values (photons/ms) preoperatively and 1 hour, 1 day, 3 weeks, and 3 months postoperatively were 6.98 ± 3.71 (SD), 19.14 ± 18.90, 16.62 ± 25.33, 10.33 ± 9.70, 8.74 ± 4.64, respectively, with the coated IOL and 8.65 ± 5.73, 22.08 ± 16.23, 13.44 ± 13.71, 7.50 ± 4.11, and 7.03 ± 3.70, respectively, with the control IOL. No significant differences were found in flare, visual acuity, ACO, PCO, tilt, or centration between the coated IOL and the control IOL at any timepoint. CONCLUSION: No significant differences in flare or capsule performance were found between the coated IOL and control IOL.

Effect of haptic material and number of intraocular lens on anterior capsule contraction after cataract surgery.

PURPOSE: To evaluate changes over time of the anterior capsule opening size after phacoemulsification, based on haptic number and composition of three acrylic intraocular lenses (IOLs). METHODS: Fifty-five patients (70 eyes) were included. All underwent phacoemulsification followed by implantation of either an acrylic IOL with two-haptic (one-piece, 26 eyes; three-piece, 22 eyes), or four-haptic (one-piece, 22 eyes). The area of the anterior capsule opening size was measured one week postoperatively (baseline) and at three months. RESULTS: There was a significant reduction in the area of the anterior capsule opening from one week as compared to three months postoperatively in all groups (p < 0.001). However, there was no significant difference in the reduction in the anterior capsule opening between the IOLs (p = 0.36). CONCLUSIONS: The number and material of the haptic of the three acrylic IOLs did not influence the degree of anterior capsule opening shrinkage.

[Pseudoexfoliation syndrome and cataract surgery. Avoidance and treatment of complications]. / Pseudoexfoliationssyndrom und Kataraktchirurgie. Vermeidung und Behandlung von Komplikationen.

Eyes with pseudoexfoliation syndrome often exhibit insufficient mydriasis, zonular weakness and pronounced fibrotic capsular shrinkage. This may make cataract surgery as such difficult but also leads to postoperative complications, such as rhexis ovalization or phimosis (capsule contraction syndrome) or progressive zonular weakening with final spontaneous dislocation of the capsule-implant complex (CIC). To avoid or correct for this special techniques and implants may be used: as prophylaxis, intracameral adrenalin and retroiridal capsulorhexis, iris retractors or dilators, various models of capsular tension and bending rings, bimanual capsule ring implantation, capsular bag stabilization with iris retractors or segments and secondary capsulorhexis may be used. Rhexis phimosis may be excised by a special diathermic probe, a subluxated CIC may be sutured to the sclera either in toto or the lens only after removal from the capsule bag, the latter also to the posterior iris surface. When luxated into the vitreous cavity, the CIC may be lifted to the iris plane and refixed as described or exchanged for a new lens sutured into the sulcus or an angle or iris-supported anterior chamber lens.

Computational model of evolving lens capsule biomechanics following cataract-like surgery.

Cataract surgery is an invasive procedure whereby lens fibers are removed through a permanent central hole, or capsulorhexis, in the surrounding lens capsule and replaced with an artificial intraocular lens (IOL). Remnant lens epithelial cells subsequently transdifferentiate to a more contractile and synthetic wound-healing phenotype, which causes significant structural and mechanical adaptations of the residual lens capsule. The goal of this study is to present a computational model capable of capturing salient features of the biomechanical evolution of the lens capsule following cataract-like surgery. The model is shown to predict marked long-term increases in thickness and stiffness of the lens capsule nearest the edge of the capsulorhexis comparable to reported measurements. Such models represent a first step toward understanding better the long-term interactions between the residual lens capsule and implanted IOL, thus initiating a new paradigm for the design of improved IOLs, including those having an accommodative feature.

Posterior capsule opacification assessment and factors that influence visual quality after posterior capsulotomy.

PURPOSE: To study the correlation between posterior capsule opacification (PCO) and intraocular straylight and visual acuity. DESIGN: Prospective noninterventional study. METHODS: We measured visual acuity (VA), logarithm of minimal angle of resolution (logMAR) and intraocular straylight (C-Quant straylight parameter log[s]) under photopic conditions before and 2 weeks after YAG capsulotomy in 41 patients (53 eyes) from the Centro de Oftalmología Barraquer in Barcelona and the University Eye Clinic, Paracelsus Medical University in Salzburg. Photopic pupil diameter was also measured. To document the level of opacification, pupils were dilated and photographs were taken with a slit lamp, using retroillumination and the reflected light of a wide slit beam at an angle of 45 degrees. PCO was subjectively graded on a scale of 0 to 10 and using the POCOman system. A multiple regression analysis was performed to evaluate factors that influence straylight after capsulotomy. RESULTS: Straylight correlated well with retroillumination and reflected-light PCO scores, whereas VA only correlated with retroillumination. Both VA and straylight improved after capsulotomy. Straylight values varied widely after capsulotomy. Multiple regression analysis showed that older age, large ocular axial length, hydrophobic acrylic intraocular lenses (IOLs), and small capsulotomies are factors that increased intraocular straylight. CONCLUSION: Intraocular straylight is a useful tool in the assessment of PCO. It correlates well with PCO severity scoring methods. When performing a posterior capsulotomy, factors such as age, IOL material, axial length, and capsulotomy size must be taken into consideration, as they influence intraocular straylight.

Correlación entre la localización del lente intraocular, según biomicroscopia ultrasónica,y diferentes parámetros quirúrgicos en pacientes operados de catarata / Correlation between the location of the intraocular lens according to ultrasonic biomicroscopy and several surgical parameters in patients operated from cataract

OBJETIVO: Determinar la correlación entre la localización del lente intraocular en cámara posterior por biomicroscopia ultrasónica, diferentes parámetros quirúrgicos en pacientes operados de catarata. MÉTODOS: Se realizó un estudio descriptivo, prospectivo y transversal en el Instituto Cubano de Oftalmología Ramón Pando Ferrer durante el período de enero a junio del 2007. Se estudiaron variables como: edad, sexo, etiología de la catarata, técnica quirúrgica, localización del lente intraocular según biomicroscopia ultrasónica, así como complicaciones transoperatorias y posoperatorias. RESULTADOS: El 79 por ciento de todos los pacientes operados tenían entre 60 y 79 años de edad y algo más de la mitad correspondió al sexo femenino con un 59 por ciento. La catarata senil fue la etiología que predominó con un 74 por ciento y en el 68 por ciento de los casos el lente se localizó por biomicroscopia ultrasónica en el saco capsular. En los ojos donde el lente intraocular se localizó fuera del saco, la proporción de complicaciones transoperatorias y posoperatorias fueron significativamente mayoritarias, mientras que en los ojos donde el lente intraocular se encontraba en el saco, la mayoría no presentó complicaciones transoperatorias ni posoperatorias. CONCLUSIONES: Las diferencias entre las distintas localizaciones del lente intraocular se encontraron con significación estadística en el tipo de catarata, la presencia de complicaciones transoperatorias y posoperatorias, sin embargo, no se encontró relación estadística significativa entre la localización del lente intraocular con la técnica quirúrgica utilizada

OBJECTIVE: To determine the correlation between the location of the intraocular lens in the posterior chamber using ultrasonic biomicroscopy and the different surgical parameters in patients operated from cataract. METHODS: A prospective, descriptive and cross-sectional study was carried out in Ramón Pando Ferrer Cuban Institute of Ophthalmology in the period of January to June 2007. The studied variables were age, sex, etiology of cataracts, surgical technique, location of the intraocular lens using ultrasonic biomicroscopy, as well as transoperative and postoperative complications. RESULTS: Seventy nine percent of all the surgical patients were 60-79 years of age and 59 percent were females. The senile cataract was the prevailing etiology for 74 percent and the lens was located in the capsular sac using ultrasonic biomicroscopy in 68 percent of the cases. In those eyes where the intraocular lens was off the sac, the ratio of transoperative and postoperative complications was significantly higher, whereas most of the eyes with the IOL placed in the sac did not have either transoperative or postoperative complications. CONCLUSIONS: The differences between the different locations of the intraocular lens were statistically significant in terms of the type of cataract; however, there was not any significant statistical association between the location of the intraocular lens and the surgical technique

Ex vivo quantification of the time course of contractile loading of the porcine lens capsule after cataract-like surgery.

Cataract surgery is an invasive procedure that replaces the quasi-spherical native lens fibers with a flat prosthetic device, which initially reduces mechanical stress within the remnant lens capsule and, ultimately, leads to contraction of the capsule about the implant. Although resultant changes in geometry have been quantified previously, little is known about the loads associated with this contraction. We present a novel experimental culture device to quantify ex vivo the time course of increases in tension within the contracting lens capsule after cataract-like surgery. Results demonstrate that contraction reaches steady state within approximately one month with a mean tension of 1.45 mN/mm and Cauchy (true) stress of 13.4 kPa. A significant increase in alpha-smooth muscle actin (alpha-SMA) was also found in post-cultured compared to fresh lens capsules, thus suggesting that transdifferentiated lens epithelial cells (LECs) modulated the contraction. Quantification of loads imparted by the contracting lens capsule is important for assessing implant/capsule interactions and implant stability in vivo. Because contraction of the capsule may be modulated in part by LECs attempting to restore their native mechanical environment, our results further suggest a possible mechanism for the long-term errant changes in capsular structure commonly observed after surgery.

Altered mechanical behavior and properties of the human anterior lens capsule after cataract surgery.

Several studies have quantified the mechanics of the normal lens capsule, motivated in large part by the need to understand better the mechanism of accommodation. In addition to this principal physiologic function, the lens capsule also plays a significant clinical role by housing the prosthetic lens implanted during cataract surgery. This procedure alters dramatically the mechanical environment of the capsule, which may modulate the errant behavior of lens epithelial cells that leads to capsular contraction and deposition of non-native matrix proteins. Although much is known about histological alterations within the post-surgical capsule, little is known about the altered mechanics. We performed uniaxial mechanical tests on normal and post-surgical human anterior lens capsules and found, for the first time, that cataract surgery leads to a significant stiffening of the capsule nearest the capsulorhexis edge. These data promise to be important for developing predictive tools capable of elucidating interactions between the post-surgical capsule and implant.

Documentation of capsular opacification and incomplete cell migration barrier formation by ThinOptX IOL using Miyake-Apple view.

The purpose of this study was to evaluate the in situ relationship of ThinOptX intraocular lens (IOL) in a cadaveric donor eye with posterior capsular opacification (PCO), following report of high PCO rates with this IOL. A cadaveric donor eye implanted with ThinOptX IOL and received at our eye bank was fixed in 10% formalin after retrieval of corneoscleral button. The globe was sectioned at equator and evaluated from the posterior (Miyake-Apple) view. Complete iridectomy was performed and IOL evaluated from the anterior (surgeon's) view. The IOL was well centered in the bag. A thick (Grade 4) Sommering ring was seen with centripetal extension across the IOL edge margin. The anterior capsule showed fibrosis and distortion of the capsulorrhexis margin. It seems from our findings that in some cases, the edge of the ThinOptX IOL may not provide an adequate barrier to epithelial cell migration and PCO formation. This can have clinical implications which need evaluation in large clinical and histopathological studies.

Absence of SPARC leads to impaired lens circulation.

SPARC is a matricellular glycoprotein involved in regulation of extracellular matrix, growth factors, adhesion, and migration. SPARC-null mice have altered basement membranes and develop posterior sub-capsular cataracts with cell swelling and equatorial vacuoles. Exchange of fluid, nutrients, and waste products in the avascular lens is driven by a unique circulating ion current. In the absence of SPARC, increased circulation of fluid, ions, and small molecules led to increased fluorescein distribution in vivo, loss of resting membrane polarization, and altered distribution of small molecules. Microarray analysis of SPARC-null lenses showed changes in gene expression of ion channels and receptors, matrix and adhesion genes, cytoskeleton, immune response genes, and cell signaling molecules. Our results confirm the hypothesis that the regulation of SPARC on cell-capsular matrix interactions can increase the circulation of fluid and ions in the lens, and the phenotype in the SPARC-null mouse lens is the result of multiple intersecting functional pathways.

Effect of trypan blue staining on the elastic modulus of anterior lens capsules of diabetic and nondiabetic patients.

PURPOSE: To determine whether trypan blue causes a significant difference in the biomechanical properties (stiffness) of diabetic and nondiabetic anterior lens capsules and to determine whether diabetes significantly alters the stiffness of anterior lens capsules. SETTING: Veterans Administration Boston Healthcare Center System, Jamaica Plain, Massachusetts, USA. METHODS: In this unmasked prospective randomized controlled experimental study, anterior lens capsules were obtained from diabetic and nondiabetic patients approved for cataract surgery. Four treatment groups were created: (1) capsules of nondiabetic patients without trypan blue; capsules of nondiabetic patients with trypan blue; (3) capsules of diabetic patients without trypan blue; (4) capsules of diabetic patients with trypan blue. Anterior lens capsule stiffness as a function of elastic (Young's) modulus (kilopascals) was measured with the Hysitron TriboIndenter. RESULTS: The use of trypan blue led to significantly stiffer anterior lens capsules (P= .036). Trypan blue had the greatest effect on the stiffness of diabetic lens capsules (P= .046). CONCLUSION: Trypan blue contributed to increased capsule stiffness during capsulorhexis, especially in diabetic patients.

[Central corneal thickness measurement by optical coherence tomography after Nd: YAG capsulotomy in patients with posterior capsule opacity]. / Ocena zmiany grubosci rogówki metoda optycznej koherentnej tomografii po wykonaniu kapsulotomii Nd: YAG laserem u pacjentów z zacma wtórna.

PURPOSE: Opacification of the posterior capsule remains the most frequent complication of cataract-intraocular lens surgery. Nd: YAG laser capsulotomy is actually the most common procedure performed to remove the posterior capsule opacification. YAG laser secondary posterior capsulotomy can be associated with significant complications. Possible problems include among others, corneal oedema. Our study has to determine whether the neodymium:yttrium-aluminium-garnet (Nd: YAG) capsulotomy performed in postoperative posterior capsule opacification, has an impact on corneal thickness measured by means of the optical coherence tomography. MATERIAL AND METHODS: 55 patients (43 females and 12 males), who underwent Nd: YAG capsulotomy in posterior capsule opacification, were enrolled to the study. Mean age was 65.1 years (range 23-87). Patients were examined before and one day, week, month, three months and six months after Nd: YAG capsulotomy. Central corneal thickness was measured with use of OCT, anterior chamber depth with OCT, endothelial cell density was estimated with specular microscopy. Besides, slit lamp examination, including fundus examination, and intraocular pressure measurement were performed. Visual function was assessed in terms of best corrected distance visual acuity by means of EDTRS type charts. Median of the total laser power and single impact laser power and count of impacts were determined. In all cases medical history was taken and analyzed. RESULTS: Statistically, significant changes of central corneal thickness at one day, week, month and three months after capsulotomy were observed. Highest relative percentage change at first day (1.9) was noted. Statistically significant correlation between central corneal thickness change and total laser power and single impact laser power was found in patients 1 month and 3 months after treatment. CONCLUSIONS: (1) Only temporary central corneal thickness increase was observed as assessed by means of OCT. (2) Nd: YAG capsulotomy should be performed with the minimal possible energy delivered to the eye.

Spontaneous closure of anterior capsule tear.

We report a case of anterior capsule tear that was closed spontaneously by fibrotic tissue during the postoperative period. The tear was inadvertently created during intraocular lens (IOL) implantation in the capsular bag. The IOL remained stable in the postoperative period, with excellent centration and no compromise in vision.

Effect of a capsular tension ring on prevention of intraocular lens decentration and tilt and on anterior capsule contraction after cataract surgery.

PURPOSE: To investigate the effect of a capsular tension ring (CTR) on the prevention of marked decentration and tilt of the intraocular lens (IOL), severe anterior capsule contraction, and refractive prediction error after cataract surgery. METHODS: Forty-seven eyes of 43 patients that had an implantation of a CTR during phacoemulsification surgery due to zonular instability (CTR group), and 34 fellow eyes that did not receive a CTR (no-CTR group) were enrolled. The degree of IOL decentration and tilt and the anterior capsule opening area were measured using a Scheimpflug videophotography system. RESULTS: No significant differences were found between the two groups in the mean degree of IOL decentration (0.34 mm in the CTR group, 0.29 mm in the no-CTR group; P=0.1401), tilt angle (2.82 degrees in the CTR group, 2.56 degrees in the no-CTR group; P=0.3173), anterior capsule opening area (24.3 mm2 in the CTR group, 23.6 mm2 in the no-CTR group; P=0.7620), or refractive prediction error (P=0.3459). CONCLUSION: In eyes with either zonular dehiscence or weakness, a CTR can prevent marked IOL decentration and tilt and severe anterior capsule contraction, and may lead to prevention of refractive prediction error.

Optical aberrations in pseudophakic eyes after 2.5-mm Nd:YAG laser capsulotomy for posterior capsule opacification.

PURPOSE: To evaluate aberrometric outcomes in eyes with posterior capsule opacification after 2.5-mm Nd: YAG laser capsulotomy compared to pseudophakic eyes without posterior capsule opacification. METHODS: Photographic image analysis of posterior capsule opacification was performed on 36 eyes that showed advanced posterior capsule opacification (case group) and on 36 eyes which showed absence of posterior capsule opacification (control group). Best spectacle-corrected visual acuity (BSCVA) and wavefront analysis were performed in the control group and in the case group after 2.5-mm capsulotomy. RESULTS: Mean BSCVA in the case group after treatment was significantly higher than before treatment (P < .05) and similar to the BSCVA in the control group (P > .1). Aberrometric analysis was performed on the control group, but light scattering prevented the analysis in posterior capsule opacification before capsulotomy, which was then performed after the intervention in 18 (50%) eyes. Mean total high order aberrations and 3rd order aberrations were significantly higher in the case group than in the control group (P < .05). Fourth and 5th order aberration values were similar between the case and control groups (P > .06). CONCLUSIONS: Our wavefront results can detect a deterioration of visual quality in patients that underwent a 2.5-mm Nd:YAG capsulotomy compared to pseudophakic patients not affected by posterior capsule opacification. This difference cannot be detected by standard visual acuity examination. Further study is needed to clarify whether our high order aberration findings were related to small, 2.5-mm capsulotomies and whether aberrometry may be indicative for mild to moderate posterior capsule opacification.