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PubMed1993

Cataract surgical techniques.

Cataract surgery continues to evolve as modifications in techniques are introduced. Extracapsular surgery, whether by phacoemulsification or planned extracapsular cataract extraction, is a very safe and effective technique. Maintaining versatility in operative techniques, depending on the clinical situation, is a distinct challenge for the cataract surgeon. Adequate surgical planning, coupled with meticulous surgical technique, gives optimal results. Innovations in wound architecture provide intraoperative and postoperative advantages to the surgeon and to the patient. Capsulorhexis is the preferred method of capsulotomy in phacoemulsification and planned extracapsular cataract extraction. Hydrodissection and related techniques are useful in all types of extracapsular cataract extraction. This article reviews techniques in cataract surgery with an emphasis on the recent literature.

Cataract↗

PubMed1994

Techniques and instruments for cataract surgery.

New techniques for cataract surgery have evolved around access to the cataract, a renewed interest in nuclear expression extracapsular techniques, and a near-completion of the developmental cycle of phacoemulsification back to the original "divide and conquer" strategies. Options to improve access to the cataract include surgical pupil revision, self-retaining iris retractors, and surgical techniques for operating through a small pupil. Nucleus expression through a capsulorhexis is facilitated by global hydrodissection and hydrostatic tilting of the nucleus before removal. New phacoemulsification strategies revolve around the Phaco-Chop method that emphasizes nuclear rim fracturing.

Cataract Extraction↗

PubMed1998

Capsular opacification after cataract surgery and capsule.

The lens capsule, the keystone of modern cataract surgery, has been the subject of some important and interesting investigations over the past year. This review addresses 1) inhibition of posterior capsule opacification (surgical techniques, intraocular lens design, and pharmacologic methods); 2) treatment of posterior capsule opacification; and 3) characteristics of the capsule. Of special interest are techniques for inhibiting posterior capsule opacification in pediatric patients by optic capture through a posterior capsulorhexis, the concept that sharp optic edges markedly decrease posterior capsule opacification as compared with round-edged implants, and promising work demonstrating that an immunotoxin may be effective in prevention of posterior capsule opacification.

Adolescent↗

PubMed2001

Capsulotomy.

Research is continually seeking to better describe the relationship between pseudophakic capsular opacification and underlying cell biology, surgical technique, and intra-ocular lens biomaterial and design. Outcomes are reviewed from prospective, randomized studies that investigate the importance of capsulorhexis size, pharmacological treatment, and lens material in influencing capsular opacification and the need for capsulotomy. The results of several studies support the role of lens edge profile in inhibiting lens epithelial cell migration. A large post-mortem study also examines how lens type may affect anterior capsular opacification formation. Of particular interest is a histological report that sheds additional light on understanding cellular processes in posterior capsu-lar opacification.

Cataract↗

PubMed2002

Management of pediatric cataract and lens opacities.

The diagnosis and surgical management of cataracts in children has benefitted from improvements in microsurgical techniques. Intraocular lens placement has become standard in children 2 years of age and older. Initial experience with intraocular lens implantation in infants found a high rate of surgical complications. However, refinements in surgical techniques may lesson these complications. Posterior capsule opacification is a frequent postoperative problem after pediatric cataract surgery. Posterior continuous curvilinear capsulorhexis with anterior vitrectomy is an effective means to prevent opacification of the visual axis in children.

Cataract↗

PubMed2006

Restoration of accommodation.

PURPOSE OF REVIEW: This review examines the current status of accommodation restoration concepts with reference to the recent, published peer-reviewed literature with an emphasis on physiological aspects of accommodation and presbyopia. RECENT FINDINGS: The mechanisms of accommodation and the causes of presbyopia are described. The physiological amenability of the accommodative structures in the presbyopic eye to accommodation restoration is discussed. General theoretical concepts of accommodation restoration are introduced. The methods that have been used to assess accommodation restoration, including the use of animal models, drug stimulated accommodation, subjective near-vision tests and objective measurements, are reviewed. SUMMARY: While physiological and clinical evidence supports the notion that accommodation can be restored to the presbyopic eye, progress in this potentially exciting area is hindered by the scarcity of good, large-scale clinical studies using objective measurement techniques to evaluate the outcomes of accommodation restoration concepts.

Accommodation, Ocular↗

PubMed2007

Adjunct devices for managing challenging cases in cataract surgery: capsular staining and ophthalmic viscosurgical devices.

PURPOSE OF REVIEW: Cataract surgeons should employ all reasonable technology to facilitate safe and consistent outcomes. Knowledge of adjunct devices to enhance visualization of the capsular bag and appropriate use of ophthalmic viscosurgical devices allow for enhanced protection of intraocular structures and reduced rates of complication. RECENT FINDINGS: Trypan blue is US Food and Drug Administration-approved for facilitating visualization of the anterior capsule. Animal data demonstrate Brilliant Blue G to be an effective capsular stain with a superior safety profile. Healon5 is a safe viscosurgical device that is particularly useful in children, poorly dilating pupils, intraoperative floppy-iris syndrome, and intumescent cataracts. The viscoadaptivity of Healon5 enables its utility throughout the procedure of cataract extraction. The recent literature on capsular dyes and advances in ophthalmic viscosurgical technology is reviewed. SUMMARY: Inadequate capsular visualization and poor tissue stabilization/protection increase the chance of discontinuous capsulorhexis, retained nuclear material, vitreous loss and corneal decompensation. Utilization of adjunctive tools in the setting of challenging cataract cases can significantly limit adverse intraoperative outcomes and result in reproducible surgical success.

Animals↗

PubMed2004

Surgical detachment of Descemet's membrane and endothelium imaged over time by in vivo confocal microscopy.

A 90-year-old woman developed a large circular capsulorhexis-like defect in Descemet's membrane as a complication of small incision cataract surgery. Nine months post-surgery, in vivo confocal microscopic examination of the temporal mid-peripheral cornea revealed an endothelial cell density of 934 +/- 69 cells/mm2 (normal range 1566-3088 cells/mm2). Endothelial pigmented deposits were visible as scattered hyper-reflective areas on the posterior endothelial surface. Descemet's folds were also noted. In vivo confocal microscopy performed 3 years later showed the temporal mid-peripheral corneal endothelial density (in the region of the break) was 948 +/- 66 cells/mm2. A reduction of endothelial polymegathism and pleomorphism was observed. Imaging in the region of the temporal portion of the original Descemet's defect showed well-defined linear structures with hyper-reflective edges. Compared to 3 years previously, the cornea at the level of Descemet's membrane appeared to have greater reflectivity. This case demonstrates how microstructural changes in the cornea can be described and analysed over time with the assistance of in vivo confocal microscopy.

Aged↗

PubMed2004

A mathematical model of factors that influence the performance of accommodative intraocular lenses.

In this work a mathematical model of capsule movement during pseudophakic accommodation is described to allow identification and evaluation of factors that may explain the variation in effect of accommodative intraocular lenses (IOLs) between patients. The model assumes that increasing vitreous pressure pushes the lens capsule forward as a circular diaphragm and that this movement is from a fixed fulcrum. With an IOL in situ, the capsule is taken to have a non-uniform thickness due to the presence of the anterior capsulorhexis. The model assumes a uniform capsular elasticity and ignores contributions from cellular elements such as posterior capsule opacification. Using our model and a regression formula to calculate capsular bag size, taking into account axial length and keratometry values, we are able to predict accommodative effect in individual patients. By simple geometry we have developed a mathematical model to identify variables that are important in pseudophakic accommodation. It provides the basis for the development of a more complex model that would address the movement of a lens taking into account the influence of the zonular system during accommodation.

Accommodation, Ocular↗

PubMed1997

Cataract surgery and pupil size in patients with diabetes mellitus.

PURPOSE: Constriction of the pupil during phacoemulsification and intraocular lens (IOL) implantation in patients with diabetes mellitus was studied. METHODS: Before surgery a combination of 0.75% cyclopentolate and 2.5% phenylephrine was applied topically to the eyes of 32 patients with diabetes mellitus and 25 age-matched controls. Epinephrine was mixed with buffered saline solution and used during the surgery. The surgical procedure included capsulorhexis, phacoemulsification in the posterior chamber and implantation into the capsular bag of a heparine surface-modified poly(methyl metacrylate) IOL with an optic diameter of 5.0 mm. The durations of phacoemulsification and the whole surgical procedure were recorded. Measurements of the horizontal pupillary diameter were taken before surgery, after phacoemulsification and at the end of the surgery. RESULTS: There was no significant difference in pupil size between controls and the diabetic group before the operation. Surgically induced miosis after phacoemulsification and at the end of operation were significantly more pronounced in the diabetic group than in controls (p < 0.05) (p < 0.05). Phacoemulsification and the entire surgical procedure took significantly longer time when performed in the diabetic eyes (p < 0.05) (p < 0.05). CONCLUSION: We conclude from these data that constriction of the pupil during cataract surgery is more pronounced in diabetic eyes as compared to controls.

Aged↗

PubMed2005

Three-year follow-up of posterior capsule opacification with two different silicone intraocular lenses.

PURPOSE: To compare posterior capsule opacification (PCO) after cataract surgery with implantation of two silicone intraocular lenses (IOLs) with different designs. METHODS: We carried out a prospective, clinical study of 116 patients randomized to standardized phacoemulsification with implantation of CeeOn Edge (n = 57) or SI40NB (n = 59) IOLs. The follow-up period was 3 years. To evaluate PCO morphologically, digital images were obtained and analysed using evaluation of posterior capsule opacification computer software (epco). The neodymium:YAG (Nd:YAG) capsulotomy rate was recorded. RESULTS: At 2 and 3 years, the eyes with SI40NB IOLs had significantly more PCO than those with the CeeOn Edge IOLs (p = 0.00014 and p = 0.002). Nine Nd:YAG capsulotomies were performed in the SI40NB group and none in the CeeOn Edge group. This difference was statistically significant (p = 0.003). In some patients a regression of PCO was noticed and confirmed using epco. Statistically less PCO was noted when the capsulorhexis rim was placed so that it covered all 360 degrees of the optic of the IOL. CONCLUSIONS: A clinically and statistically significant difference in PCO development between CeeOn Edge and SI40NB IOLs at 2 and 3 years postoperatively was found. These findings support earlier studies indicating that a sharp edge of the optic is a more important factor in IOL design than IOL material in the prevention of PCO.

Aged↗

PubMed1998

Lens epithelial cell regression on the posterior capsule with different intraocular lens materials.

BACKGROUND/AIMS: Posterior capsular opacification (PCO) is caused by proliferation and migration of lens epithelial cells (LECs) across the posterior capsule and is the commonest cause of reduced vision after cataract surgery. The influence of intraocular lens (IOL) material on the process of LEC migration was studied. METHODS: 90 eyes underwent standardised extracapsular surgery, with capsulorhexis and "in the bag" IOL placement. They were randomised to receive a three piece 6 mm lens of PMMA, silicone, or polyacrylic (AcrySof, Alcon, Fort Worth, TX, USA). On days 7, 30, 90, 180, and years 1 and 2 high resolution digitised retroillumination images were taken of the posterior capsule. The presence of LECs was determined at 90 days and 2 years, and their progression or regression was established by serial examination of images. RESULTS: LECs were seen in 93% of silicone and 97% of PMMA IOLs at 90 days, compared with 46% of polyacrylic (p < 0.001). At year 2 LECs were present in all patients with silicone or PMMA lenses, whereas 62% of patients with polyacrylic IOLs had LECs (p < 0.001). Of those patients with LECs at day 90 LEC regression occurred in 8% with silicone IOLs and 15% of PMMA cases, compared with 83% of patients with polyacrylic IOLs (p < 0.0001). CONCLUSION: The presence of LECs on the posterior capsule was considerably lower with polyacrylic than PMMA or silicone IOLs and LEC regression occurred more frequently. The lower incidence of LECs and the higher rate of regression may explain why PCO formation appears to be reduced with polyacrylic lenses. This has important clinical implications for the prevention of PCO.

Acrylic Resins↗

PubMed1998

Comparison of decentration and tilt between one piece and three piece polymethyl methacrylate intraocular lenses.

BACKGROUND: The extent of the decentration and tilt was prospectively compared between one piece polymethyl methacrylate (PMMA) and three piece PMMA intraocular lenses (IOLs) which were implanted in the capsular bag after performing continuous curvilinear capsulorhexis. METHODS: 91 patients underwent a one piece PMMA IOL implantation in one eye as well as the implantation of the three piece PMMA IOL with polyvinylidene fluoride loops in the opposite eye. The length of the lens decentration and the angle of the tilt were quantitated using the anterior eye segment analysis system (EAS-1000) at 1 week as well as 1, 3, and 6 months postoperatively. RESULTS: The mean length of the decentration in the one piece IOL was smaller than that in the three piece IOL at 1 week (p = 0.0092), 1 month (p = 0.0044), 3 months (p = 0.0069), and 6 months (p = 0.0010) postoperatively. However, no significant difference was found in the degree of the tilt between the two types of IOLs throughout the observation periods. CONCLUSION: These results clarified that the one piece PMMA IOL with rigid PMMA haptics implanted in the capsular bag provides a better centration than the three piece PMMA IOL with flexible haptics, whereas the tilt was the same between the two types of IOLs.

Aged↗

PubMed1998

Initial clinical experience with the picosecond Nd:YLF laser for intraocular therapeutic applications.

AIMS/BACKGROUND: Compared with nanosecond (ns) pulses of conventional Nd-YAG lasers, picosecond (ps) laser pulses allow intraocular surgery at considerably lower pulse energy. The authors report initial clinical experiences using a Nd:YLF ps laser for the treatment of various indications for photodisruption. METHODS: A Nd:YLF laser system (ISL 2001, wavelength 1053 nm) was used to apply pulse series of 100-400 microJ single pulse energy at a repetition rate of 0.12-1.0 kHz. Computer controlled patterns were used to perform iridectomies (n = 53), capsulotomies (n = 9), synechiolysis (n = 3), and pupilloplasties (n = 2). Other procedures were vitreoretinal strand incision (n = 2) and peripheral retinotomy (n = 1). For comparison, 10 capsulotomies and 20 iridotomies were performed with a Nd:YAG ns laser. The ps laser cut of an anterior capsule was assessed by scanning electron microscopy (SEM). RESULTS: Open, well defined iridectomies (mean total energy 4028 mJ, mean diameter 724 microns), were achieved at first attempt in 92% of the cases. In 64% an iris bleeding and in 21% an IOP increase of > 10 mm Hg occurred. All capsulotomies were performed successfully (mean energy 690 mJ/mm cutting length) but with a high incidence of intraocular lens damage. The attempted vitreoretinal applications remained unsuccessful as a result of optical aberrations of the eye and contact lens. Although ps laser capsulotomies and iridectomies required much higher total energy than ns procedures, the resulting tissue effects of the ps pulses were more clearly defined. SEM examination of a ps incision of the anterior lens capsule demonstrated, nevertheless, that the cut was more irregular than the edge of a continuous curvilinear capsulorhexis. CONCLUSION: Series of ps pulses applied in computer controlled patterns can be used effectively for laser surgery in the anterior segment and are considerably less disruptive than ns pulses. The ps laser is well suited for laser iridectomies while the ns laser is preferable for posterior capsulotomies. As vitreoretinal applications remained unsuccessful, the range of indications for intraocular photodisruption could not be extended by the ps laser.

Humans↗

PubMed2000

Cataract extraction and intraocular lens implantation in children with uveitis.

AIM: To evaluate the long term results of cataract surgery with intraocular lens implantation (IOL) in children with uveitis. METHODS: The study included 10 eyes in seven children (age 3.5-10 years, mean 6.5 years). The cataract surgery included capsulorhexis of the anterior and the posterior capsule, anterior vitrectomy in some eyes, and implantation of a heparin surface modified (HSM) poly(methyl methacrylate) (PMMA) IOL into the capsular bag. RESULTS: Follow up periods ranged from 1 to 5 years. Best corrected visual acuity after surgery reached 20/50-20/20 in all but two eyes. Opacities or membranes requiring reoperation developed in seven eyes. Glaucoma developed in three eyes after the cataract operation. CONCLUSION: These results suggest that implantation of a HSM PMMA IOL is an alternative to correct aphakia also in children with uveitis.

Anticoagulants↗

PubMedDate not supplied

Incidence of cystoid macular edema after uncomplicated phacoemulsification.

We determined the incidence and causes of clinical and angiographic cystoid macular edema (CME) after uncomplicated phacoemulsification and intraocular lens implantation in otherwise normal eyes. This study comprised 252 eyes of 252 patients who had uncomplicated phacoemulsification with continuous curvilinear capsulorhexis and in-the-bag acrylic intraocular lens implantation. The presence of clinical and angiographic CME was evaluated 45 days after surgery, using fundus fluorescein angiography. Age, sex, cataract type, iris color, and real phacoemulsification time of the patients were also recorded. The mean age of the patients was 69.86 (range 60-82) years). Clinical CME was not detected in any eye at any postoperative visit. There were 23 cases with angiographic CME (9.1%). There were no significant differences between the groups who were later found to be angiographically CME-positive or CME-negative in any variable recorded (p >0.05). The incidences of clinical and angiographic CME after uncomplicated phacoemulsification were 0 and 9.1%, respectively. These results indicate that the occurrence of clinical CME has greatly reduced after uncomplicated phacoemulsification operations, but the incidence of angiographic CME is still nearly equal to the incidence of the extracapsular technique.

Aged↗

PubMedDate not supplied

Subjective visual experience and pain level during phacoemulsification and intraocular lens implantation under topical anesthesia.

PURPOSE: To investigate the subjective visual experiences and pain during the phacoemulsification and intraocular lens (IOL) implantation under topical anesthesia, and whether these parameters change according to the stage of phacoemulsification cataract surgery. METHODS: Forty eyes of 40 patients with cataract undergoing phacoemulsification and IOL implantation under topical anesthesia were included in this study. The patients were told that they would be asked about their visual experiences and pain level, if any, during every stage of the surgery. As for degree of the pain, a 5-grade scale was used. The surgery was divided into 9 stages, i.e., clear corneal incision, continuous curvilinear capsulorhexis, side-port incisions at 3 and 9 o'clock positions, hydrodissection, nuclear rotation, phacoemulsification, bimanual irrigation and aspiration, IOL implantation, apposition of corneal incisions with stromal hydration. RESULTS: All subjects (100%) reported that they had seen some kind of light during the operation. Thirty-eight patients (95%) said that they had seen one or more colors. In 32 patients (80%), the light intensity decreased, and colors blurred significantly following the hydrodissection. As for the pain level during surgery, the overall pain score was found to be 0.40. The highest mean pain score was noted during IOL implantation stage followed by phacoemulsification and bimanual irrigation-aspiration. CONCLUSION: Topical anesthesia is both a safe and effective method for small-incision clear corneal phacoemulsification cataract surgery. Patients may experience visual sensations, and the pain felt during the operation is low and tolerable. Visual experiences and pain level may change according to the stage of phacoemulsification cataract surgery.

Adult↗

PubMedDate not supplied

Visual results after primary intraocular lens implantation or contact lens correction for aphakia in the first year of age.

PURPOSE: The optimal role of intraocular lenses (IOLs) in infants remains a controversial topic. Some ophthalmologists advocate correction with a contact lens (CL), whereas others recommend an IOL correction. Our study compared visual acuity, ocular alignment, retreatment rate and binocular vision outcomes in children treated with these two methods at our clinic. METHODS: This study included 41 children with unilateral congenital cataract who underwent cataract surgery with posterior capsulorhexis and anterior vitrectomy, coupled with (IOL group, n=18) or without (CL group, n=23) primary IOL implantation. All infants underwent the first surgery during the first 12 months of their life and they were operated on in the period from 1994 to 1999. The mean age at surgery was 3.11+/-2.65 months (range: 28 days to 11 months). All patients were prescribed the same half-time reduced occlusion therapy. Good cooperation of the parents and good compliance with patching were the necessary conditions to include a patient in the study. Between January and February 2003, the final visual acuity and binocular vision outcomes were examined. RESULTS: The mean final visual acuity (logarithm of the minimum angle of resolution) of the operated eye was 0.43+/-0.33 for the IOL group and 0.58+/-0.39 for the CL group (p=0.14). The mean interocular difference in visual acuity was 0.22+/-0.29 for the IOL group and 0.56+/-0.31 for the CL group (p=0.042). The reoperation rate was 78% in the IOL group compared with 35% in the CL group (p=0.017). Esotropia or exotropia of more than 8 prism diopters were present in 55% of children (10/18) in the IOL group compared with 83% of children (19/23) in the CL group (p=0.039). CONCLUSIONS: We suggest that correction of aphakia after unilateral congenital cataract surgery with primary IOL implantation results in improved visual acuity, improved binocular vision outcome and less occurrence of strabismus, but a higher rate of complications requiring reoperation. Further studies with a larger pediatric patient group are necessary to confirm the optimal treatment of aphakia after unilateral congenital cataract extraction.

Aphakia, Postcataract↗