Phacoemulsification And Aspiration Research Articles

Effect of a new phacoemulsification and aspiration handpiece on anterior chamber stability.

To evaluate the responsiveness of 3 phacoemulsification and aspiration (PEA) systems and a new handpiece to occlusion break by measuring anterior chamber depth (ACD) and intraocular pressure (IOP). Zengyo Suzuki Eye Clinic, Kanagawa, Japan. Experimental study. ACD change during intentional occlusion breaks was observed and evaluated using the slit side view (SSV) method and IOP measurement with the Centurion Vision System (Group 1), Centurion Vision System with Active Sentry (Group 2), Infiniti Vision System (Group 3), and Constellation Vision System (Group 4). 5 eyes were included per group. Occlusion breaks were triggered at IOP of 30 mm Hg, vacuum limits of 550 mm Hg, and aspiration rate of 40 mL/min. ACD change ratio, surge duration, and surge volume were analyzed from videos of SSV and IOP measurement. The smallest ACD change was observed in Group 2 with SSV. ACD change ratios in Groups 1 to 4 were 17.5% ± 3.9%, 7.3% ± 1.2%, 35.7% ± 9.5%, and 74.1 ± 7.7%, respectively. Surge duration and surge volume were calculated only for Groups 1 and 2 and were significantly lower in Group 2 than in Group 1 (0.32 ± 0.03 vs 1.17 ± 0.07 seconds; 18.91 ± 4.70 vs 45.70 ± 0.83 μL). In these 2 groups, ACD change ratio correlated with surge volume. This study evaluated the responsiveness of 3 PEA systems and a new handpiece to occlusion breaks by measuring IOP and ACD. The Active Sentry system was useful for maintaining the ACD even during occlusion breaks.

Surgical removal of cataract in an Asiatic black bear (Ursus thibetanus) by phacoemulsification and aspiration.

A twenty-year-old male Asiatic black bear (Ursus thibetanus) presented at the Rakuno Gakuen University Animal Medical Center with a 10-year history of bilateral blindness and cataracts. Surgical treatment of bilateral cataracts by extracapsular lensextraction using phacoemulsification and aspiration (PEA) was performed under general anesthesia. An anterior capsulectomy was performed using micro iris scissors and micro anterior lens capsule forceps. The cataract was removed with PEA using the two-handed technique. After surgery, systemic corticosteroids, anti-inflammatory drugs and antibiotics were administered. After cataract removal, the bear had recovered vision, and good quality vision has been maintained to date (15 months). PEA can be a safe and effective treatment for cataracts that impair vision in bears.

Objective classification of zonular weakness based on lens movement at the start of capsulorhexis.

PurposeTo quantify zonular weakness based on lens movement at the start of continuous curvilinear capsulorhexis (CCC) and establish a classification system for it.SettingKozawa Eye Hospital and Diabetes Center, Mito, Japan.DesignRetrospective interventional case series.MethodsWe examined 402 consecutive eyes of 316 patients who underwent CCC, phacoemulsification and aspiration (PEA), and intraocular lens (IOL) implantation. The movement of the lens capsule was measured using images from video recordings of the CCC procedure. Zonular weakness was classified based on the shifted distance: Grade I, less than 0.20 mm; Grade II, 0.20–0.39 mm; and Grade III, greater than 0.40 mm. For each of these grades, we examined the use of the capsule stabilization device during PEA, the surgical procedure for lens removal, and IOL fixation.ResultsWe classified 276 eyes (68.6%) as Grade I, 102 eyes (25.4%) as Grade II, and 24 eyes (6.0%) as Grade III. As the grade increased, the use of the capsule stabilization device in PEA and scleral suture fixation of IOL increased.ConclusionsZonular weakness was quantified by measuring the movement of the lens capsule. An objective classification of zonular weakness based on lens movement may be useful for selecting the appropriate device and procedure during cataract surgery.

Retrospective evaluation of phacoemulsification and aspiration in 41 horses (46 eyes): visual outcomes vs. age, intraocular lens, and uveitis status.

To determine the effect of age at the time of surgery, intraocular lens (IOL) placement, and presence of chronic uveitis on visual outcome after phacoemulsification and aspiration (PA) of cataracts in horses. Records of 41 horses (46 eyes) receiving unilateral or bilateral PA. Retrospective analysis of horses receiving unilateral or bilateral PA at the NCSU-VTH (35 horses, 39 eyes) and in Northern Italy (six horses, seven eyes) was performed. Visual status at last follow-up was compared to age at the time of surgery, IOL status, and presence of chronic uveitis preoperatively. Seven horses with chronic uveitis also underwent placement of a suprachoroidal cyclosporine implant. Clinical ophthalmic examinations and owner questionnaires were used to evaluate visual status. Twenty-one of 46 eyes (46%) received an IOL and 12 of 46 eyes (26%) had chronic uveitis. Overall, 25 of 46 eyes (54%) were visual at last follow-up (mean 35.1 ± 34.8 months). Age (mean 8.6 ± 7.7 years) was not significantly associated with visual outcome. Fourteen of 21 (67%) pseudophakic eyes and 11 of 25 (44%) aphakic eyes were visual at last follow-up (P = 0.342). Eyes with preoperative chronic uveitis were significantly less likely to be visual (3 of 12 eyes [25%]) than horses without preoperative chronic uveitis (22 of 34 eyes [65%]) (P = 0.023). Horses with chronic uveitis had significantly less favorable visual outcome after PA. Older age at surgery and IOL use were not associated with poor visual outcome.

Changes in Vitreous Temperature During Intravitreal Surgery

To determine how different intraoperative surgical procedures affect the midvitreous temperature. The vitreous temperatures were monitored continuously with an intravitreal thermocouple in 87 eyes of 81 cases undergoing vitrectomy. Thirty-three eyes had diabetic retinopathy (DR), 35 eyes had an epiretinal membrane, and 19 eyes had an idiopathic macular hole. In eyes with DR, the correlation between the number of photocoagulations (PCs) and the change in temperature was analyzed. The temperature was also recorded before and after combined phacoemulsification and aspiration (PEA) and vitrectomy in 10 eyes. The average midvitreal temperature before the vitrectomy was 33.0 ± 1.3°C, 30.7 ± 1.7°C after core vitrectomy, 32.9 ± 1.3°C after membrane peeling, and 29.2 ± 1.4°C after peripheral vitrectomy. The temperature before PC was 29.8 ± 1.3°C, and it increased to 31.5 ± 1.9°C post-PC. The differences in the temperatures between consecutive procedures were significant (P < 0.01, respectively, Wilcoxon signed-rank test). The difference in the temperatures of the same procedures among the different diseases was not significant except after membrane peeling. A significant correlation was detected between the number of PCs and the duration of the PCs, and between the duration of PCs and the change in vitreous temperature after PC (r = 0.719, P = 0.0010, and r = 0.800, P = 0.0002, respectively, Spearman's rank correlation coefficient test). The temperature after PEA decreased significantly by 2.3°C. Our results showed that vitreous temperatures vary during different vitrectomy procedures.

New side-view imaging technique for observing posterior chamber structures during cataract surgery in porcine eyes

BackgroundTo develop a side-view imaging technique for observing the dynamic behavior of posterior chamber structures (PCSs) in porcine eyes which mimics closed-eye cataract surgery in humans.MethodsEnucleated porcine eyes were placed into liquid nitrogen for 5 seconds and immediately bisected at about a 45-degree angle to the equatorial plane. The anterior portion was attached firmly to a glass slide with superglue and sprinkled with wheat flour. Phacoemulsification and aspiration (PEA) was performed as in humans on 10 consecutive porcine eyes. The movements of the PCSs were monitored through the glass slide with a high-resolution video camera set below the cut surface of the eye. The intraocular pressure (IOP) was monitored during the surgery. The highest IOP, operation time, and volume of irrigation fluid of 10 whole eyes were compared to that obtained from the bisected eyes glued to a glass slide. In a second set of experiments, the strength of the seal between the bisected eye and the glass slide was tested in three sets of eyes: 1) frozen eye fixed with superglue with wheat flour for 3 min; 2) frozen eye fixed with superglue for 3 min; and 3) non-frozen eye fixed with superglue for 30 min. The highest IOP that led to a disruption of the seal was compared among the three groups.ResultsPEA was successfully performed on 9 of 10 (90%) eyes with the movements of the PCSs clearly observed. The average maximum intraocular pressure of the 9 bisected eyes was 55.8 ± 4.7 mmHg and that for the 10 unbisected eyes was 55.3 ± 5.0 mmHg (P = 0.650). The frozen eye fixed with superglue in combination with wheat flour (Group 1) had the strongest sealing strength with an average IOP at the breaking point of 117.3 ± 36.2 mmHg.ConclusionsOur side-view imaging technique can be used to evaluate the changes of the PCSs during intraocular surgery and for surgical training of new residents.

Effect of three treatment protocols on acute ocular hypertension after phacoemulsification and aspiration of cataracts in dogs

To compare the effect of topical latanoprost, intracameral carbachol, or no adjunctive medical therapy on the development of acute postoperative hypertension (POH) and inflammation after routine phacoemulsification and aspiration (PA) of cataracts in dogs. Retrospective study. Dogs received either one drop of topical 0.005% latanoprost (21 dogs, 39 eyes), an intracameral injection of 0.3 mL of 0.01% carbachol (15 dogs, 30 eyes), or no adjunctive therapy (46 dogs, 90 eyes) immediately following PA of cataract(s). Intraocular pressure (IOP) was measured in all dogs 2 and 4 h after surgery. IOP was measured and aqueous flare assessed at 8 am the day after surgery. Carbachol-treated dogs had significantly higher mean IOP (33.2 +/- SD 20.8 mmHg) 2 h after surgery than dogs receiving no adjunctive therapy (22.0 +/- SD 14.1 mmHg) (P = 0.049). There were no significant differences in IOP among groups at any other time point. There were no significant differences in number of POH episodes between dogs treated with carbachol (47%), latanoprost (29%), or dogs that received no adjunctive therapy (33%). There were no significant differences in mean aqueous flare grade between eyes treated with latanoprost (1.7 +/- SD 0.4) or carbachol (1.4 +/- SD 0.6), and eyes that received no adjunctive therapy (1.7 +/- SD 0.4). Topical 0.005% latanoprost or intracameral injection of 0.3 mL of 0.01% carbachol after PA in dogs did not reduce POH or increase intraocular inflammation compared to dogs not receiving adjunctive therapy after PA of cataracts.

Disruption of the Posterior Chamber–Anterior Hyaloid Membrane Barrier During Phacoemulsification and Aspiration as Revealed by Contrast-Enhanced Magnetic Resonance Imaging

To determine the effect of phacoemulsification and aspiration (PEA) in different surgical settings on the posterior chamber-anterior hyaloid membrane (AHM) barrier. Eighty enucleated porcine eyes divided into 8 groups underwent lens extraction at a bottle height of 35 or 95 cm by 1 of the following 4 procedures: standard PEA, standard PEA without hydrodissection (sPEA-), sPEA- including 5 minutes of irrigation of the anterior chamber, and sPEA- including 20 cycles of deflation (5 seconds each cycle) and inflation (10 seconds each cycle) of the anterior chamber. Distribution of gadopentetate dimeglumine (gadolinium-diethylenetriamine pentaacetic acid [Gd-DTPA]) in the irrigating fluid was assessed by magnetic resonance imaging (MRI). The most common MRI pattern was the posterior chamber type, where Gd-DTPA was localized in the anterior and posterior chambers, followed by AHM detachment, in which Gd-DTPA was evident beneath the posterior lens capsule. The least common was AHM tear, in which Gd-DTPA entered the vitreous cavity through a tear in the AHM. Logistic regression analysis revealed prolonged irrigation (P< .001) and deflation/inflation of the anterior chamber (P< .001) as risk factors for AHM detachment and hydrodissection (P= .04) as a risk factor for AHM tear. Changes in intraocular pressure can disrupt the posterior chamber-AHM barrier during PEA. Cataract surgeons should reexamine their surgical settings to avoid unnecessary stress on the eye.

Primary Phacoemulsification and Aspiration Combined with 25-Gauge Single-Port Vitrectomy for Management of Acute Angle Closure

To describe a technique using phacoemulsification and aspiration (PEA) combined with 25-gauge single-port vitrectomy as a primary treatment for acute angle closure (AAC). Seventeen consecutive cases of AAC were treated with 1) transconjunctival limited single-port vitrectomy with a 25-gauge vitrector and 2) transcorneal PEA and cortex removal followed by implantation of foldable intraocular lenses (IOL). Intraocular pressure (IOP) control was achieved in all 17 eyes examined. Mean preoperative IOP was 51.8+/-13.1 mmHg, and mean IOP on postoperative day 1 was 18.3+/-8.5 mmHg. Additional anti-glaucoma surgery was necessary in one eye. IOL could not be implanted because of zonular dialysis in one eye. Postoperative complications were seen in three cases (one retinal hemorrhage and two papilledema). The PEA procedure is efficient as a primary treatment of AAC. Single-port vitrectomy with a 25-gauge vitrector facilitated PEA and IOL implantation.

High infusion pressure in conjunction with vitreous surgery alters the morphology and function of the retina of rabbits

To investigate the effects of high infusion pressure in conjunction with pars plana vitrectomy (PPV) on retinal morphology and function in rabbits. Pars plana vitrectomy was performed under urethane (0.8 mg/kg) anaesthesia in the right eye of albino rabbits following phacoemulsification and aspiration (PEA). The left eyes were not touched. After PEA, the animals were divided into two groups. In six eyes, intraocular pressure (IOP) was increased to 80 mmHg for 30 mins (high-pressure group) and in five eyes IOP was maintained at 40 mmHg for 30 mins (low-pressure group). The IOPs were regulated by the height of the bottle of balanced salt solution (BSS) and monitored with a pressure transducer. After the pressure elevation, vitreous fluid was collected to measure the glutamate concentration. Then, PPV was performed for 15 mins in both groups under an infusion pressure of 40 mmHg. In five additional rabbits, PEA alone was performed in the right eye, and vitreous fluid was collected (PEA group). Functional alterations were assessed by recording visual evoked potentials (VEPs) and electroretinograms (ERGs). Ten days after the IOP changes, the animals were killed with intravenous pentobarbital sodium and the eyes were prepared for histological analysis. Damage to retinal ganglion cells (RGCs) was quantified by counting the number of cells in the ganglion cell layer (GCL). The contralateral eyes in the high-pressure group served as controls (n = 6). The mean implicit time (IT) of the VEPs in the high-pressure group was significantly longer than that before the IOP elevation, by 114-124% (p < 0.05, paired t-test), and also than that of control eyes (p < 0.05, anova followed by t-test). No significant changes in the VEPs were detected in either the low-pressure group or the PEA group. There were significantly fewer cells in the GCL in the high-pressure group (24.7/mm) than in the control animals (41.4/mm; p < 0.05, Dunnett's test). The number of cells in the GCL in the low-pressure and PEA groups did not significantly differ to that in the controls. The amplitudes of the ERG a- and b-waves were not significantly changed (p > 0.05, paired t-test). These results suggest that high infusion pressure in conjunction with PPV leads to morphological and functional changes in the retina. The absence of ERG changes and presence of VEP changes suggest that these changes were due to damage to RGCs, which supports the morphological observations.

Aqueous and Vitreous Penetration of Levofloxacin after Topical and/or Oral Administration

To investigate the aqueous and vitreous penetration of levofloxacin, the drug was administered topically and/or orally to patients undergoing vitrectomy. Thirty-six patients undergoing initial vitrectomy with phacoemulsification and aspiration (PEA) were enrolled, and were divided randomly into three groups. Group 1 was treated with topical application of levofloxacin (three times on the day before surgery and seven times on the day of surgery), Group 2 received oral administration of levofloxacin (200 mg twice on the day before surgery and 200 mg at 3 hours before surgery), and Group 3 received both topical and oral levofloxacin according to the above schedules. The concentration of levofloxacin was measured in aqueous humor and vitreous fluid samples obtained during surgery. In Groups 1, 2, and 3, the mean levofloxacin concentration in aqueous humor was 0.765+/-0.624 micro g/mL, 1.279+/-0.440 micro g/mL, and 1.823+/-0.490 micro g/mL, respectively, while the mean levofloxacin concentration in vitreous fluid was <0.02 micro g/mL, 1.455+/-0.445 micro g/mL, and 1.369+/-0.530 micro g/mL, respectively. Oral administration of levofloxacin at a dose of 400 mg/day was sufficient for the prophylaxis of ocular infections, because the drug concentrations in both aqueous humor and vitreous fluid were higher than the MIC90 values for major ocular pathogens. Topical application of levofloxacin achieved adequate drug levels in aqueous humor, but not in vitreous fluid, while combined topical and oral administration had an additive effect on the drug concentration in aqueous humor.

Achievement of Less Invasive Cataract Surgery

Phacoemulsification and aspiration (PEA) has become the most popular type of cataract surgery. The safety of cataract surgery has been dramatically improved due to the development of surgical techniques and associated instruments. However, corneal endothelial damage still represents a serious complication, as excessive damage can lead to irreversible bullous keratopathy. Collision of lens fragments to corneal endothelium by turbulent flow causes physical breakdown of the endothelial cells. We report a case in which corneal endothelial damage occurred by the collision of lens fragments during phacoemulsification and aspiration. The outcome prompted us to perform safer operations with new surgical instruments.

Postoperative Refractive Error of Secondary Intraocular Lens Implantation After Simultaneous Vitrectomy and Lensectomy

To determine postoperative refractive errors of secondary intraocular lens (IOL) implantation, this study was performed in 42 eyes of 42 patients following secondary IOL implantation fixed in the sulcus after simultaneous vitrectomy and phacoemulsification and aspiration. Controls were 138 eyes of 124 patients with cataract who underwent phacoemulsification and aspiration and IOL implantation. The spread between expected and actual refraction (actual - expected) was -0.81 +/- 0.86 diopters (average +/- standard deviation) in the study group and 0.01 +/- 0.91 diopters in the control group (statistically significant, P < .001, Student's t test). The actual refractive errors in the study subjects were shifted toward myopia compared with the controls.

Phacoemulsification Associated Corneal Damage Evaluated by Corneal Volume

To determine the usefulness of the Pentacam corneal volume assay in the assessment of corneal endothelial damage caused by phacoemulsification and aspiration (PEA). Prospective, comparative, observational case series. PEA was performed in 85 eyes by three surgeons under different conditions. Central cell density (CD) was determined using a specular microscope before and one month after surgery. Pentacam was used before and one day, one week, and one month after surgery to determine 3- and 10-mm corneal volumes. For all surgeons, no significant differences in the 3-mm corneal volumes were noted between the before and one-month after surgery values. However, 10-mm corneal volumes at one month were significantly higher than preoperative levels. No correlation was noted between the increasing rate of the 10-mm corneal volume and decreasing rate of CD. Pentacam-determined corneal volumes may be useful in assessing PEA-caused corneal damage.

Surgical Results of Combined Pars Plana Vitrectomy, Phacoemulsification, and Intraocular Lens Implantation for various Vitreoretinal Diseases

To evaluate the results and complications of combined pars plana vitrectomy (PPV), phacoemulsification and aspiration (PEA), and intraocular lens (IOL) implantation. A total of 117 eyes from 114 patients who had undergone PPV combined with PEA and IOL implantation were retrospectively analyzed. Combined surgery was performed for a wide variety of vitreoretinal diseases. Intraoperative and postoperative complications were also reviewed. The postoperative BCVA improved by 2 lines or more in 85 eyes (72.6%). Intraoperative complications consisted of retinal tears in 14 eyes (12.0%) and posterior capsular rupture in 2 eyes (1.7%). Iatrogenic retinal tears occurred more frequently in eyes with a macular hole than in eyes with any other disease (p=0.005, chi-square test). Postoperative complications consisted of posterior capsule opacification (PCO) (21 eyes), transient IOP elevation (29 eyes), vitreous hemorrhage (6 eyes), anterior chamber fibrin exudation (11 eyes), posterior iris synechia (8 eyes), neovascular glaucoma (1 eye), and recurrent retinal detachment (RD) (2 eyes). Fibrin exudation occurred more frequently in eyes with proliferative diabetic retinopathy (PDR) and RD than in eyes with any other disease (p=0.03, chi-square test). PCO occurred more frequently in eyes with PDR than in eyes with any other disease (p=0.03, chi-square test). The present study suggests that a high success rate can be achieved when recently improved PPV techniques are combined wi th PEA and IOL implantation. The complications that were observed following this combined treatment varied with respect to the vitreoretinal disease present prior to surgery.

Free Radical Development in Phacoemulsification Cataract Surgery

Phacoemulsification and aspiration (PEA) has become the most popular cataract surgery, due to the establishment of safe surgical techniques and development of associated instruments. However, corneal endothelial damage still represents a serious complication, as excessive damage can lead to irreversible bullous keratopathy. In addition to causes such as mechanical or heat injuries, free radical formation due to ultrasound has been posited as another cause of corneal endothelium damage in PEA. Ultrasound in aqueous solution induces cavitation, directly causing water molecule disintegration and resulting in the formation of hydroxylradicals, the most potent of the reactive oxygen species. Considering the oxidative insult to endothelial cells caused by free radicals, their presence in the anterior chamber may represent one of the most harmful factors during these procedures. Indeed, some researchers have recently started to evaluate PEA from the perspective of oxidative stress. Conversely, the major ingredient in ophthalmic viscosurgical devices (OVDs), which are indispensable for maintaining the anterior chamber in PEA surgery, is sodium hyaluronate, a known free radical scavenger. OVDs can thus be expected to provide some anti-free radical effect during PEA procedures. In addition, since commercially available OVDs display different properties regarding retention in the anterior chamber during PEA, the anti-free radical effect of OVDs is likely to depend on behavior during irrigation and aspiration. The present study followed standard PEA procedures in an eye model and measured hydroxylradicals in the anterior chamber using electron spin resonance. The kinetics of free radical intensity and effects of several OVDs during clinical PEA were also demonstrated. These studies may be of significance in re-evaluating OVDs as a chemical protectant for corneal endothelium, since the OVD has thus far only been regarded as a physical barrier. In addition, many reports about corneal endothelium damage during PEA have been published, but objective evaluation of various damaging factors has been difficult. The present assay of free radicals in a simulation of clinical PEA offers the first method to quantitatively assess stress on the corneal endothelium.

Post-cataract Surgery Endophthalmitis Treated with Core Vitrectomy: A Case Report

Postoperative endophthalmitis is one of the most serious complications after cataract surgery though its frequency may be low. We report a case with post-cataract extraction bacterial endophthalmitis treated favorably by core vitrectomy through pars plana with anterior vitrectomy cutter (A-vit). The patient, a 72-year-old woman, presented with blurred vision 7 days after phacoemulsification and aspiration (PEA) and intraocular lens (IOL) implantation. Her initial visual acuity was counting fingers. As hypopyon and corneal edema progressed in a few hours, we decided to perform vitectomy. Firstly, we performed IOL explantation and anterior vitrectomy through the corneal stab incision with A-vit attached to the phaco machine. The inflammation, however, appeared to be severe. Secondly we performed core vitrectomy with the same cutter as we used in the first operation through pars plana as well as intravitreal injection of vancomycin on the following day. The inflammation was gradually subsided and her corrected visual acuity was recovered to 30/20 at 7 months after the vitrectomy. The results is suggest that for cataract surgeons in the facilities that are not equipped with 3-port vitrectomy machine, post-cataract extraction bacterial endophthalmitis of the emergency stage can be successfully treated by core vitrectomy through pars plana as well as intravitreal injection of antibiotics with neither vitreous shaving at the vitreous base nor artificial posterior vitreous detachment.

Pathology of canine cataract surgery complications

AIM: To compare pathological complications arising from 2 methods of canine cataract surgery, manual extracapsular cataract extraction (MECCE) and the more automated phacoemulsification and aspiration (PA). METHODS: Case material presented to the Comparative Ophthalmic Pathology Laboratory, University of North Carolina over the previous 20 years (1979–1999) was searched for cases with a history of prior cataract surgery. Data were obtained from the pathology accession forms, and submitting veterinarians were contacted to verify and complete missing data where possible. The slides were re-examined, histological features of surgical complications were noted and secondary changes recorded. RESULTS: Fourteen canine post-cataract-surgery cases were reviewed, the average age of the group being 7.7 years. Of the 14 eyes, 7 had surgery performed using MECCE, and 7 using PA. Of the 7 eyes that underwent MECCE surgery, 5 were enucleated and diagnosed on both clinical and pathological grounds with glaucoma. Of the 7 eyes that underwent PA, 4 were diagnosed with infectious endophthalmitis. CONCULSIONS: Complications observed were related to the surgical technique performed. Failures of manual extracapsular surgical procedures were more commonly associated with postoperative synechia and glaucoma, compared with failures of phacoemulsification, which were more commonly associated with infection and rhegmatogenous retinal detachments. CLINICAL RELEVANCE: To minimise post surgical complications, MECCE should be accompanied by rigorous efforts to reduce surgically induced inflammation, while PA should be performed using excellent aseptic technique. It is important with both techniques to totally remove cortical material while maintaining the integrity of the posterior capsule.

The Optimal Molecular Weight of Dispersive Type Sodium Hyaluronate for the Reduction of Corneal Endothelial Damage Induced by Sonication, Irrigation, and Aspiration

Purpose: The purpose of this study was to investigate the optimal molecular weight of dispersive sodium hyaluronate (Na-HA) for the reduction of corneal endothelial damage induced by sonication, irrigation, and aspiration, using enucleated pig eyes. Method: The phaco-needle of phacoemulsification and aspiration (PEA) equipment was inserted into the anterior chamber after aqueous humor replacement with a 1% Na-HA solution of various molecular weights (2420 × 10 3, 1460 × 10 3, 1100 × 10 3, 520 × 10 3 or 290 × 10 3). Then sonication, irrigation, and aspiration were conducted for 60 seconds. The residual rate of Na-HA in the anterior chamber and the damaged area of corneal endothelium were determined using an image analyzer. Results: Na-HA with a molecular weight of 1100 × 10 3 gradually disappeared from the anterior chamber after mixing with the irrigating solution, and the damaged area in only the 1100 × 10 3 group was significantly smaller compared with that in the control group. Conclusion: These results suggest that an optimal molecular weight exists for dispersive hyaluronate applied for the protection of intraocular tissues during PEA. Under the conditions of this study, Na-HA with a molecular weight of 1100 × 10 3 displayed the highest protective efficacy.

Comparison of Scheimpflug images of posterior capsule opacification and histological findings in rabbits and humans

Purpose: To compare the posterior capsule opacification in Scheimpflug photographic images produced by an electronic anterior eye segment analysis system with the histopathological findings in rabbits and humans. Setting: Department of Ophthalmology, Wakayama Medical College, Japan. Methods: Opacified posterior capsules were photographed using the EAS-1000 system (Nidek) and were then extracted during vitreous surgery for proliferative diabetic retinopathy or proliferative vitreoretinopathy in 2 patients. In rabbits, phacoemulsification and aspiration (PEA) with intraocular lens (IOL) implantation was performed. The IOL was implanted in the bag or in the sulcus. After intervals of healing, the posterior capsule was photographed with the EAS-1000 and the animals were then killed. In both clinical and experimental specimens, the posterior capsule was processed for light microscopic histology and immunohistochemistry. Results: Opacified human capsules were well imaged by the EAS-1000. Histology showed that lens epithelial cells proliferated with and without an accumulation of extracellular matrix. Details such as rolling of the capsulotomy edge were seen well. Regenerated lens fibers of Soemmering’s ring were seen as a mass within the capsule. In the rabbit model, Scheimpflug images accurately represented the capsules as they appeared histologically. Conclusion: The EAS-1000 system provided faithful, relatively high-resolution images that corresponded to the histologic findings in the posterior capsules after PEA-IOL surgery in humans and rabbits.