Safety of femtosecond laser-assisted cataract surgery: assessment of aqueous humour and lens capsule.

PURPOSE: To investigate the effect of femtosecond laser-assisted cataract surgery (FLACS) on aqueous humour and lens capsule. METHODS: This prospective randomized comparative study enrolled 19 eyes that underwent FLACS as the trial group and 20 eyes that underwent conventional phacoemulsification as the control group. The femtosecond laser platform (LLS-fs 3D; LensAR, Orlando, FL, USA) was used to generate capsulotomy (laser energy 8 µJ) and lens fragmentation (laser energy 10 µJ). Morphology of the cutting edge and cells of anterior capsule was assessed by light microscopy. The proteins in the aqueous humour were identified by mass spectrometry (Ultraflex III TOF/TOF; Bruker Dalton, Bremen, Germany). Electrolyte in the aqueous humour was detected by a chemistry analyzer (Aeroset Clinical Chemistry Analyzer; Abbott Laboratories, Abbott Park, IL, USA). RESULTS: The cutting edge of anterior capsule was saw-tooth-shaped under magnification of 200× and 400× in the trial group, while it was smooth in the control group. Intact cells were found in the boundary area next to the cutting edge of anterior capsule in both groups. ß-Crystallin B1, γ-crystallin S and transferrin were detected in the aqueous humour in the trial group. The concentrations of K+ , Na+ and Cl- in the aqueous humour in the trial group differed significantly from those in the control group (p = 0.02, 0.03 and 0.04, respectively). CONCLUSION: Femtosecond laser-assisted cataract surgery (FLACS) causes release of transferrin and crystallin from lens to aqueous humour and results in significant changes in the concentrations of K+ , Na+ and Cl- in aqueous humour. However, these changes due to FLACS have no clinical significance or toxicity.

Anterior Segment Optical Coherence Tomography Assessment After Laser Capsulotomy in Pseudophakic Eyes With Pseudoexfoliation.

PURPOSE: To assess changes in anterior-chamber depth (ACD) and angle width after neodymium:yttrium aluminum garnet (Nd:YAG) laser capsulotomy pseudophakia in eyes with pseudoexfoliation (PEX). METHODS: This prospective and interventional case series study included 25 pseudophakic eyes of 25 patients with PEX and 26 pseudophakic eyes of 26 patients without PEX scheduled for Nd:YAG laser capsulotomy in a single institution. Anterior-chamber depth and angle width were measured with anterior segment optical coherence tomography before and three days after Nd:YAG laser capsulotomy. Preoperative and postoperative measurements of ACD and angle width included the angle opening distance (AOD), measured as the perpendicular distance from the trabecular meshwork at 500 and 750 mm anterior to the scleral spur to the anterior iris surface (AOD500 and AOD750, respectively) and anterior-chamber angle (ACA) in the nasal and temporal quadrants. Main outcome measures were the changes in ACD and angle width parameters. RESULTS: The mean ACD, AOD500, AOD750, and ACA (nasal and temporal) measurements were 3.67±0.12 mm, 0.63±0.05 mm and 0.65±0.05 mm, 0.67±0.06 mm and 0.77±0.04 mm, 35.25±1.69° and 35.37±1.68° in eyes with PEX and 3.73±0.11 mm, 0.6±0.05 mm and 0.63±0.05 mm, 0.66±0.06 mm and 0.74±0.06 mm, 34.24±1.6° and 34.6±1.47° in control eyes, respectively (P>0.05 for all). After Nd:YAG laser capsulotomy, mean ACD, AOD500, AOD750, and ACA (nasal and temporal) measurements were 3.76±0.09 mm, 0.73±0.05 mm and 0.76±0.05 mm, 0.75±0.06 mm and 0.87±0.04 mm, 36.82±1.46° and 35.06±1.52° in eyes with PEX and 3.77±0.1 mm, 0.68±0.06 mm and 0.72±0.06 mm, 0.72±0.05 mm and 0.84±0.06 mm, 34.95±1.4° and 35.79±1.36° in control eyes, respectively (P=0.811, P=0.019, P=0.021, P=0.109, P=0.126, P=0.001, and P=0.01, respectively). CONCLUSIONS: The depth and width of the anterior chamber in eyes with PEX and in control eyes increased significantly after Nd:YAG laser capsulotomy. The change in the width of the anterior chamber in eyes PEX was statistically significant comparing control eyes.

The Repeatability Assessment of Three-Dimensional Capsule-Intraocular Lens Complex Measurements by Means of High-Speed Swept-Source Optical Coherence Tomography.

PURPOSE: To rebuild the three-dimensional (3-D) model of the anterior segment by high-speed swept-source optical coherence tomography (SSOCT) and evaluate the repeatability of measurement for the parameters of capsule-intraocular lens (C-IOL) complex. METHODS: Twenty-two pseudophakic eyes from 22 patients were enrolled. Three continuous SSOCT measurements were performed in all eyes and the tomograms obtained were used for 3-D reconstruction. The output data were used to evaluate the measurement repeatability. The parameters included postoperative aqueous depth (PAD), the area and diameter of the anterior capsule opening (Area and D), IOL tilt (IOL-T), horizontal, vertical, and space decentration of the IOL, anterior capsule opening, and IOL-anterior capsule opening. RESULTS: PAD, IOL-T, Area, D, and all decentration measurements showed high repeatability. Repeated measure analysis showed there was no statistically significant difference among the three continuous measurements (all P > .05). Pearson correlation analysis showed high correlation between each pair of them (all r >0.90, P<0.001). ICCs were all more than 0.9 for all parameters. The 95% LoAs of all parameters were narrow for comparison of three measurements, which showed high repeatability for three measurements. CONCLUSION: SSOCT is available to be a new method for the 3-D measurement of C-IOL complex after cataract surgery. This method presented high repeatability in measuring the parameters of the C-IOL complex.

[Assessment of retinal thickness obtain by optical coherence tomography after Nd: YAG capsulotomy]. / Ocena grubosci siatkówki na podstawie badania optycznej koherentnej tomografii po wykonaniu Nd: YAG kapsulotomii.

PURPOSE: To measure central macular thickness change after Nd: YAG capsulotomy using optical coherence tomography (OCT). MATERIAL AND METHODS: 55 patients (43 females and 12 males), mean age 65.1 +/- 13.9 years (range 21-87) who underwent Nd: YAG capsulotomy for posterior capsule opacification. Patients were examined preoperatively and one day, one week, one month, three months and six months after Nd: YAG capsulotomy. Central retinal thickness was measured by Stratus IV OCT Optical Coherence Tomography from Carl Zeiss Meditec, Inc. using "fast macular thickness" map protocol. All patients underwent ophthalmic examination including best-corrected visual acuity, fundus examination and intraocular pressure measurement. RESULTS: The initial median and range of the central retinal thickness was 212 microm (168-228), after one day 207 microm (168-232), after one week 207 microm (166-241), after one month 207 microm (163-252), after 3 months 207 microm (171-242), and 210 microm (170-235) 6 months after treatment. Proportional changes of the central retinal thickness was after one day -0.5 (-13.3 to 5.6), after one week 0.5 (-11.6 to 8.1), after one month -0.4 (-8.3 to 14.5), after 3 months 0.5 (-8.7 to 10.0) and 6 months after capsulotomy 0.5 (-5.8 to 7.7). There was no statistically significant change of the central macular thickness in any time point. Cystoid macular edema was observed in three patients 9.0 and 14 weeks after treatment. No other complications were noticed. CONCLUSIONS: Laser capsulotomy should be considered as a safe procedure for the macula. Optical coherence tomography is a useful diagnostic method that can be used in qualification and monitoring of patients undergoing Nd: YAG capsulotomy.

Capsule staining as an adjunct to cataract surgery: a report from the American Academy of Ophthalmology.

OBJECTIVE: This document evaluates currently available data in the published literature to answer the question of whether the use of dye such as indocyanine green or trypan blue to stain the lens capsule to improve visualization is safe and effective as an adjunct to cataract surgery. METHODS: Literature searches conducted in March 2003 and May 2004 retrieved 139 citations. The panel members reviewed the abstracts and selected 47 of possible clinical relevance for review. An additional 14 articles were identified for evaluation. Of the 61 articles reviewed, the panel members selected 36 for the panel methodologist to review and rate according to the strength of the evidence. A level I rating was assigned to properly conducted, well-designed, randomized clinical trials; a level II rating was assigned to well-designed cohort and case-control studies; and a level III rating was assigned to case series and case reports. RESULTS: There is level III evidence that indocyanine green, trypan blue, and fluorescein are each effective in staining the lens capsule and that indocyanine green and trypan blue provide better ease of use and visualization of the capsule than fluoroscein. There is level II evidence that staining the capsule is helpful in completing capsulorrhexis and that it is helpful for pediatric patients under age 5 years and in cases of white cataract. The overall surgical advantage of a completed continuous curvilinear capsulorrhexis using dye has not been demonstrated, but this may be related to the outcome measures chosen rather than a failure to confer advantage. There are substantial data indicating that trypan blue 0.1% is not toxic to the cornea. There are limited data suggesting that indocyanine green 0.125% to 0.5% is not toxic to anterior segment structures. CONCLUSIONS: There are data confirming that dye is safe and effective as an adjunct for capsule visualization in cataract surgery. It is reasonable to use dye when inadequate capsule visualization may compromise the outcome in cataract surgery. More studies are needed to confirm a lack of toxicity of indocyanine green and trypan blue, particularly in the event of posterior segment or longer duration exposure.

Optical coherence tomography assessment of capsule closure after cataract surgery.

PURPOSE: To develop a technique for documenting and quantifying capsule bend formation in pseudophakic eyes, evaluate when the anterior and posterior lens capsules become completely apposed to the optic, and determine how soon a capsule bend is created at the optic edge of an intraocular lens (IOL) after cataract surgery. SETTING: Medical University of Vienna, Department of Ophthalmology, Vienna, Austria. METHODS: This prospective study comprised 33 eyes of 33 patients with age-related cataract who were scheduled to have cataract surgery. All eyes had phacoemulsification with implantation of 1 of 3 types of open-loop IOLs: 1-piece acrylic (SA60AT, Alcon), 3-piece acrylic (AcrySof MA60BM, Alcon), or 3-piece silicone (911A, AMO). Each group included 11 eyes. One and 3 days and 1, 2, 3, and 4 weeks after surgery, contact between the lens capsule and IOL optic as well as capsule bend formation were evaluated using optical coherence tomography (OCT). The postoperative times at which the capsule came into contact with the IOL optic and when the capsule bend formed were determined. RESULTS: One day postoperatively, the mean distance between the anterior capsule and the IOL was 197 microm in the 1-piece acrylic IOL group, 161 microm in the 3-piece acrylic IOL group, and 220 microm in the 3-piece silicone IOL group. The posterior capsule was in contact with the IOL on the same day or earlier than the anterior capsule in 28 patients (85%). Postoperatively, the capsule bend formed at a mean of 10 days in the 1-piece acrylic group, 13 days in the 3-piece acrylic group, and 15 days in the 3-piece silicone group. The short-term reproducibility of the OCT technique was excellent (r = 0.99). CONCLUSIONS: Optical coherence tomography produced cross-sectional tomograms of capsule-IOL contact in the early postoperative period. There was no significant difference in the time to capsule bend formation between the 3 IOLs. However, capsule bend formation at the optic edge occurred earlier with the 1-piece acrylic IOL than with the 3-piece silicone IOL.

Assessment of capsular block syndrome with anterior segment optical coherence tomography.

A 59-year-old woman developed progressive, moderate myopia 1 year after routine phacoemulsification and insertion of a soft posterior chamber intraocular lens (IOL). After biomicroscopy, late capsular block was diagnosed and treated with a neodymium:YAG laser posterior capsulotomy. The myopia disappeared immediately. This case was illustrated using optical coherence tomography developed for the anterior segment. After capsulotomy, the IOL moved backward by 448 microm, corresponding to -0.75 diopter of induced myopia.

Methods of assessment of patients for Nd:YAG laser capsulotomy that correlate with final visual improvement.

BACKGROUND: This paper attempts to clarify the usefulness of various simple pre-operative measures in estimating the potential for a visually successful capsulotomy. METHODS: 24 patients attending for capsulotomy had pre-operative measures of glare with BAT tester, visibility of posterior pole and grading of posterior capsular pearls and fibrosis seen at slit lamp. Visual function was measured before and after standardised capsulotomy. Correlations of the various preoperative measures with eventual visual function improvements were calculated. RESULTS: Pearls at slit lamp and poor posterior pole visualisation were all correlated with improvements in visual acuity and contrast sensitivity after capsulotomy. Amount of fibrosis visible at slit lamp and glare assessment were not correlated with vision improvements after laser. CONCLUSION: Of the various measures that are taken prior to Nd : YAG capsulotomy, some correlate with eventual visual improvement but for others no clinical utility was found. Practitioners should note these findings as they are especially of use in more questionable or high-risk cases to help determine whether referral for PCO treatment by Nd: YAG capsulotomy is likely to benefit the patient.

Laserinterferometric assessment of pilocarpine-induced movement of an accommodating intraocular lens: a randomized trial.

PURPOSE: To measure the axial movement of an accommodating intraocular lens (IOL) induced by ciliary muscle contraction after application of pilocarpine. DESIGN: Randomized, controlled, patient- and examiner-masked trial with intrapatient comparison. PARTICIPANTS AND CONTROLS: One hundred ten eyes of 55 patients with age-related bilateral cataract. METHODS: This study was divided into 3 parts. In the first, the accommodating IOL (1CU) was compared with a 3-piece open-loop acrylic IOL that served as the control. In the second, to assess the effect of capsule fibrosis on the potential accommodating performance of the accommodating IOL, extensive polishing of the anterior capsule with a slit cannula was compared with standard surgery. In the third, the effect of a posterior capsulorhexis was compared with that of standard surgery. Anterior chamber depth (ACD) was assessed with partial coherence interferometry, measured before and after topical application of pilocarpine 2%, and near visual acuity (VA) was evaluated 3 months after surgery. MAIN OUTCOME MEASURE: Pilocarpine-induced change in ACD. RESULTS: The accommodating IOL showed a forward movement under pilocarpine with a median amplitude of movement of -314 microm (95% confidence interval [CI]: -148 to -592), compared with the backward movement of 63 microm (95% CI: 161 to -41) for the open-loop control IOL (P = 0.001). Capsule polishing and a posterior capsulorhexis had no effect on IOL movement with the accommodating IOL. The median near VA with distance correction was 20/60. CONCLUSION: Pilocarpine induced a small but significant forward movement of the accommodating IOL. However, the amount of movement was calculated to result in a refractive change of <0.5 diopters (D) in most patients, reaching 1 D or slightly more in only single cases, with a large variability of movement. Neither polishing of the capsule bag nor a posterior capsulorhexis could enhance the accommodative ability.

[Posterior capsule opacification: incidence and pathogenesis]. / Antrine katarakta: daznis, etiologija ir patogeneze.

Posterior capsule opacification (PCO) or secondary cataract is still the most common complication of cataract surgery. PCO results from the proliferation, growth, migration and transdifferentiation of lens epithelial cells left on the anterior capsule at the time of cataract surgery. Two types of PCO that are distinguished clinicaly are the fibrous and the pearl. It can be treated with Nd-YAG laser capsulotomy, but procedure is not without complications and it is not free of costs. For the United States, it has been estimated that the overall expenses for treatment of PCO are exceeded by the costs for cataract treatment itself. Consequently, a lot of experimental and clinical studies have been performed on this topic. They have led to a better understanding of the pathogenesis of the development of PCO and strategies to prevent PCO.

Intraocular lens implantation in the absence of capsular support: a report by the American Academy of Ophthalmology.

OBJECTIVE: This review was conducted to determine the safety and efficacy of open-loop anterior chamber, scleral-sutured posterior chamber, and iris-sutured posterior chamber intraocular lenses (IOLs) in eyes with inadequate capsular support for posterior chamber implantation in the capsular bag or ciliary sulcus. It also attempted to determine whether there is a preferred IOL or fixation site of choice in eyes with inadequate capsular support. METHODS: A literature search conducted for the years 1980 to 2001 yielded 189 citations related to IOL implantation in the absence of capsular support. An update search, conducted in March 2002, yielded an additional 28 articles. The Anterior Segment Panel members reviewed these abstracts and selected 148 articles of possible clinical relevance for review. Of these, 89 were considered sufficiently clinically relevant for the panel methodologist to review and rate according to the strength of evidence. A level I rating was assigned to properly conducted, well-designed, randomized clinical trials; a level II rating was assigned to well-designed cohort and case-control studies; and a level III rating was assigned to case series. Articles comparing the safety and efficacy of the IOL type and fixation site were further evaluated for the quality of the statistical methods used in the study. Studies with a rating of A or B were considered acceptable, C was borderline, and D and F were considered unacceptable as medical evidence. RESULTS: Forty-three articles with data concerning outcome of IOL insertion in eyes with inadequate capsular support had an evidence rating of level III or higher and were used in the final review of the safety and efficacy of one or more lens types and/or fixation sites. Seven articles had data about more than one lens type. Six had a statistical method rating of C or higher and were used to evaluate differences in visual outcomes and complication rates between lens types and fixation sites. CONCLUSIONS: The literature supports the safe and effective use of open-loop anterior chamber, scleral-sutured posterior chamber, and iris-sutured posterior chamber IOLs for the correction of aphakia in eyes without adequate capsular support for placement of a posterior chamber lens in the capsular bag or ciliary sulcus. At this time, there is insufficient evidence to demonstrate the superiority of one lens type or fixation site. Precise determination of small differences in visual outcome or complication rates will require a large prospective, randomized clinical trial.

Removal of reflections in the photographic assessment of PCO by fusion of digital retroillumination images.

PURPOSE: Automated image-analysis systems for objective assessment of posterior capsule opacification (PCO) depend on good image quality. One major drawback is the existence of light-reflection artifacts (Purkinje spots) in retroillumination images of the posterior capsule. Therefore, a software algorithm was developed that removes these artifacts by fusion of two or more digital images from the same eye, photographed in slightly different directions of gaze. METHODS: The image-fusion process comprises five steps: definition of a primary and a secondary image, automated segmentation of the region of interest and the Purkinje spots, manual selection of three pairs of corresponding points in both images, geometric registration and radiometric calibration of the regions to be inserted from the secondary image into the primary image. The program was tested with an image set of 30 eyes that had various degrees of PCO. A digital image acquisition system with a coaxial optical path was used to take retroillumination images from each eye in at least three different directions of gaze. RESULTS: In 28 cases all light-reflection artifacts within the capsulorrhexis rim could be removed entirely. In two cases, small parts of single Purkinje spots remained visible, because the reflections were located too closely in the primary and the secondary images. CONCLUSIONS: Fusion of digital retroillumination images provides high-quality, reflection-free PCO images. This allows objective PCO assessment systems to analyze 100% of the posterior capsule, leading to more accurate results.

Assessment of anterior capsule opacification: photographic technique and quantification.

PURPOSE: To develop and evaluate a standardized slitlamp photographic technique to document and quantify anterior capsule opacification (ACO) in the pseudophakic eye. SETTING: University of Vienna, Medical School, Department of Ophthalmology, Vienna, Austria. METHODS: In this prospective study, slitlamp photographs were taken in 29 eyes of 19 patients with ACO of varying degrees and intraocular lenses of different materials. Digital slitlamp photographs were taken by 2 examiners using a standardized protocol. The intensity of anterior fibrosis was evaluated using subjective grading by 2 masked examiners and by image analysis. RESULTS: A standardized protocol was developed for documentation of ACO. The intraexaminer (or short-term) reproducibility (r = 0.96, P < .01) and interexaminer reproducibility (r = 0.93, P < .01) were excellent. The results of image analysis used to objectively quantify ACO correlated with the subjective grading (r = 0.95, P < .01). CONCLUSION: This standardized technique of slitlamp photography and image analysis provided reproducible documentation and can therefore serve as a basis for the quantification of ACO.

Retroillumination versus reflected-light images in the photographic assessment of posterior capsule opacification.

PURPOSE: To investigate the relative merit of retroillumination and of reflected light slit-lamp-derived photographs in the assessment of the opacification of the posterior lens capsule. METHODS: Retroillumination and slit-lamp-derived reflected-light photographs were taken on 23 consecutive eyes with posterior capsule opacification (PCO) in uncomplicated pseudophakia. Subjective grading was performed on both types of photographs to evaluate the extent and density of posterior capsular opacification. Best-corrected visual acuity (BCVA) before and after YAG laser capsulotomy was used to assess the impact of capsular opacification on visual function. RESULTS: After capsulotomy all patients attained a BCVA > or = 46 letters (> or =20/32) with a mean increase of 25 letters, indicating that PCO was the cause of visual impairment in these patients. The relative capacity of retroillumination and of reflected-light photographs to adequately capture the extent and the severity of posterior capsule opacification varied considerably. Reflected-light images, in addition to frequently producing higher severity scores for the opacity than retroillumination photographs, in 4 of 23 eyes (17.4%) proved to be the only technique able to document the presence of PCO. CONCLUSIONS: Our results indicate that, with respect to retroillumination images, reflected-light photography has an increased ability to adequately capture the presence and the severity of PCO and that the use of only retroillumination images may lead to its underestimation. This may be relevant to clinical studies aiming to evaluate incidence and progression of this condition.