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At least 19 recordsLinked to original sources
PubMed1995

Comparison of endothelial cell loss and phacoemulsification energy during endocapsular phacoemulsification surgery.

We counted central corneal endothelial cells and measured corneal thickness in 64 human eyes before and three months after cataract extraction and posterior chamber lens implantation. Cataract surgery was the same in all patients and included capsulorhexis and posterior chamber phacoemulsification of the nucleus. Total phacoemulsification energy and time were recorded. A heparin-surface-modified intraocular lens or a regular poly(methyl methacrylate) lens, both having the same design and a 5.0 mm optic, was implanted in the capsular bag with the aid of sodium hyaluronate (Healon). Mean endothelial cell loss was 4%. However, the change in cell density did not correlate with the total phacoemulsification energy used during surgery. Three months after surgery, the central corneal thickness was the same as it had been preoperatively. The results suggest that phacoemulsification in the posterior chamber is a safe procedure even in cases with a hard nucleus.

Aged↗
PubMed1990

Phacoemulsification and intraocular lens implantation in patients with cataract. Experiences of a beginning 'phacoemulsification surgeon'.

Phacoemulsification was performed in 125 eyes (123 patients) selected from 145 eyes (143 patients) referred for planned extracapsular cataract extractions and intended posterior chamber intraocular lens implantations. These procedures were the first clinical phacoemulsification operations performed by the author. In the total material, lesion of the posterior capsule or zonules occurred in 7 eyes (4.9%). Vitreous loss occurred in 3 of these eyes (2.1%). In cases with vitreous loss the operative strategy was changed to implantations of anterior chamber lenses. Five of the 7 eyes that experienced intraoperative complications, had preoperative complicating conditions other than cataract. Visual acuity 6 to 12 weeks postoperatively was 6/12 or better in 87% (126/145) of the eyes. Excluding preoperative posterior segment pathology, 98.4% (126/128) achieved this visual acuity. This study demonstrates that it is possible to include phacoemulsification as the main treatment modality in planned ECCE operations without significant increase in complication rates even for a 'beginning phacoemulsification surgeon'.

Adult↗
PubMed1989

[Protective effect of the anterior lens capsule: corneal endothelial cell loss following intercapsular phacoemulsification compared with phacoemulsification with large open capsulotomy].

In an experimental study using rabbits, the intercapsular technique was performed in 20 eyes to make a small anterior capsulotomy. A large, "can opener" capsulotomy was performed in 20 eyes, and ten eyes (five non-operated animals) served as controls. Endothelial cell loss was determined by vital staining with Trypan blue and Alizarin red S. Average endothelial cell loss with the intercapsular technique was 1.2%; with the can opener technique the cell loss was 6.6%. This difference was statistically significant (p less than 0.01). The percentage in the control eyes was 0.05%. Positive relations between endothelial cell loss related to phacoemulsification time and/or the amount of irrigating fluid used existed for the can opener group only (p less than 0.01). These results demonstrate that the presence of an almost intact anterior lens capsule during removal of lens substance is protective to the corneal endothelium.

Animals↗
PubMed1993

A comparison of corneal endothelial changes after use of Healon or Viscoat during phacoemulsification.

We conducted a prospective, randomized trial comparing the endothelial protective effects of Healon (Kabi Pharmacia Ophthalmics, Inc., Monrovia, California) and Viscoat (Alcon Surgical, Inc., Ft. Worth, Texas) in 59 eyes of 59 patients undergoing iris-plane or posterior-chamber phacoemulsification with posterior-chamber lens implantation. We evaluated postoperative central and superior changes in corneal thickness and corneal endothelial cell density, coefficient of variation in cell size, and percentage of hexagons. In the overall series, at one day postoperatively, corneal thickness increased 17% centrally and superiorly in eyes receiving Healon compared to 12% centrally and 11% superiorly in eyes receiving Viscoat (P < .05). Sixteen weeks postoperatively, superior endothelial cell loss was 11.6% in eyes receiving Healon compared to 2.1% in eyes receiving Viscoat (P < .01). In the iris-plane phacoemulsification group, superior cell loss at week 16 was 13.8% in eyes receiving Healon and 0.5% in eyes receiving Viscoat (P < .04). In the posterior-chamber phacoemulsification group, there were no significant differences between the Healon and Viscoat subgroups. Comparing the surgical techniques, in the Healon group, central cell loss at week 16 was 13.8% in the iris-plane phacoemulsification subgroup and 0.6% in the posterior-chamber phacoemulsification subgroup (P < .03), and coefficient of variation in cell size increased 3.7% in the iris-plane subgroup and decreased 6.8% in the posterior-chamber subgroup (P < .04). In the Viscoat group, there were no significant differences between surgical techniques at week 16. Viscoat provided greater corneal endothelial protection than Healon during iris-plane phacoemulsification. In eyes receiving Healon, posterior-chamber phacoemulsification resulted in less corneal endothelial trauma than the iris-plane technique.

Aged↗
PubMed1993

Formation of free radicals during phacoemulsification.

During phacoemulsification cavitation bubbles are formed. These bubbles are believed to be one source of damage to corneal endothelium seen after phacoemulsification. Free radicals are induced whenever cavitation bubbles implode. The aim of this study was to confirm the initiation of free radicals by phacoemulsification and to correlate the power of ultrasound in the phacoemulsification process to the amount of free radicals formed, using both in vitro and in vivo techniques. The formation of free radicals was determined by adding luminol to a buffer and measuring the chemoluminescence in vitro and in rabbit eyes (Lumacounter 2080 or a single-photon-counting apparatus) during phacoemulsification. The data obtained show that free radicals are formed during phacoemulsification and that the amount of free radicals correlates with the power of ultrasound. Furthermore, the radical formation could be inhibited by the radical scavengers SOD, Healon and Healon GV. These results were achieved both in vitro in the test tube and in vivo in rabbit eyes. By showing that the addition of SOD to the irrigation buffer during phacoemulsification decreases the corneal endothelial cell damage, we show that free radicals could have a role in postoperative complications seen clinically.

Animals↗
PubMed1995

[Endothelial cell loss after phacoemulsification and 3.5 vs. 5 mm corneal tunnel incision].

This prospective study was performed to compare the central endothelial cell loss (ECL) after phacoemulsification and 3.5 with 5 mm temporal clear-corneal incision. Moreover, the influence of ultrasound time and power on postoperative endothelial cell density was evaluated. PATIENTS AND METHODS. Sixty-two patients (age 71 +/- 7.7 years) without corneal pathology were operated by phacoemulsification (Storz, Premiere) with a temporal, self-sealing, two-step clear-corneal incision followed by posterior chamber IOL implantation under viscoelastic (1% sodium hyal-uronate). Thirty-one one-piece plate-haptic foldable silicone IOLs (Chiron C10; Staar Surgical AA-4203) were implanted by an injector through a 3.5 mm incision (group A). The other 31 PMMA IOLs (Pharmacia 809P) were implanted through a 5 mm incision (group B). One surgeon performed all operations with the same technique (bimanual phacoemulsification in the capsular bag). Sutureless wound closure was performed in group A, while the wounds in patients of group B were closed with a single radial stitch. The central endothelial cell counts were recorded preoperatively, on days 2-5 and 6 months postoperatively using contact specular microscopy. RESULTS. The collective data revealed a cell loss of 7.9% (+/- 4.1 SD) on days 2-5 postoperatively and 6.7% (+/- 2.9) after 6 months. A direct linear relationship was found to exist between ultrasound time (UT) and ECL. In group A (7 patients) the ECL slightly increased from 3.5% in the first week postoperatively to 3.8% after 6 months, operated under UT < or = 1 min 30 sec. The ECL decreased from 8.2% to 6.4% after 6 months in group A (19 patients), operated under UT of 1 min 30 sec, and from 10.8% to 8.9% under UT of 2 min 31 sec-3 min 30 sec (5 patients). The ECL in group B decreased from 6.3% in the first postoperative week to 5.4% 6 months postoperatively, operated under UT < or = 1 min 30 sec (10 patients), from 8.1% to 7%, operated under UT of 1 min 31 sec-2 min 30 sec (14 patients), and from 11.2% to 10.4% under UT of 2 min 31 sec-3 min 30 sec (7 patients). CONCLUSION. Endothelial cell loss of 6.7% after phacoemulsification through a temporal clear-corneal incision compares favorably with other series in which cell loss was determined following cataract surgery with or without IOL implantation. Phacoemulsification and 3.5 mm clear-corneal incision evoked less ECL of 6.2% compared with phacoemulsification and 5 mm clear-corneal incision with ECL of 7.3% after 6 months.

Aged↗
PubMed1993

[Comparison of phacoemulsification and planned extracapsular cataract extraction].

40% of cataract surgeons in German speaking countries use phacoemulsification as the procedure of choice for cataract extraction while the other 60% still use the planned extracapsular extraction. The more procedures a surgeon performs the stronger is the tendency toward performing phacoemulsification. The opening technique of the anterior capsule is chosen accordingly: for phacoemulsification capsulorhexis is preferred, while for the planned extracapsular extraction can opener - or letter box - technique is usually done. The length of the sclero-corneal incision is 3.2 mm in phacoemulsification, 6.2 mm for a PMMA posterior chamber lens implantation and 9-13 mm for the planned extracapsular extraction. We prospectively compared both procedures with each group including 100 consecutive patients. The mean irrigation volume was 96.6 +/- 48.8 ml in the phacoemulsification group as opposed to 48.1 +/- 26 ml in the planned extracapsular extraction group. The mean duration of irrigation was 130 +/- 67 sec in the first versus 129 +/- 76 sec in the second group; mean endothelial cell loss was 7.9% versus 7.1%. No correlation was found between endothelial cell loss and duration of irrigation. Mean postoperative astigmatism measured 1.0 +/- 0.49 in the first group as compared to 3.3 +/- 1.7 dpt in the second group. Except for the astigmatism, our study could not detect significant differences regarding the outcome between both procedures. There are advantages to the phacoemulsification procedure, however, such as a smaller incision (e.g. tunnel technique), a closed irrigation-aspiration system, controlled intraocular pressure and the more frequent use of capsulorrhexis. Preferred indications and possible advantages regarding intra- and postoperative complications are discussed.

Aged↗
PubMed1993

Refractive results after phacoemulsification and ECCE. A comparative study.

The refractive results were evaluated in 79 patients undergoing cataract extraction by phacoemulsification using a 6-7 mm tunnel incision, and compared with a group of 77 patients undergoing planned extracapsular cataract extraction (ECCE) by the same surgeon. A mean increase in the keratometric cylinder of 0.05D and 0.52D was found in the phacoemulsification and the extracapsular cataract extraction group, respectively. This was significantly different from zero for the extracapsular cataract extraction group (p < 0.05) but not for the phacoemulsification group (p > 0.05). By vector analysis, the mean surgically induced astigmatism was 0.91D and 1.36D in the phacoemulsification and the extracapsular cataract extraction group, respectively (p < 0.01). The IOL power prediction error (spectacle plane) was found to be 0.17D (+/- 0.69 SD) in the phacoemulsification group and 0.02 D (+/- 0.79 SD) in the extracapsular cataract extraction group, respectively. We conclude that phacoemulsification improves the surgical control of the refractive outcome of cataract surgery.

Aged↗
PubMed1983

A comparison of the effects of phacoemulsification and nucleus expression on endothelial cell density.

A series of patients undergoing extracapsular cataract extraction by phacoemulsification (1,126) or nucleus expression (632) were studied to evaluate the relative effects of emulsification time, irrigating volume, and surgical technique on endothelial cell density. The collective data revealed a higher cell loss with phacoemulsification (15%) than with nucleus expression (12%). Patients over 69.5 years appeared to be more vulnerable to the effects of phacoemulsification than those below 69.5 years. Although the data were subjected to combinations and permutations of age, sex, time, and volume, no direct correlation between emulsification time and/or irrigating volume and endothelial cell loss was shown. When data sets for individual surgeons were analyzed, the most striking difference was between the endothelial effect of anterior chamber phacoemulsification (26% average reduction) and that of posterior chamber phacoemulsification (13% average reduction).

Age Factors↗
PubMed1994

Corneal endothelial cell loss after phacoemulsification using nuclear cracking procedures.

This study assessed corneal endothelial damage in endocapsular phacoemulsification surgery using a nuclear cracking procedure in which the nucleus was divided into four quadrants and emulsified. Forty-five eyes had phacoemulsification using this technique, and 33 eyes had phacoemulsification using undivided sculpting techniques (without cracking). We examined the extent of endothelial cell loss at one and three months after surgery using specular microscopy. We also measured ultrasound time, time spent for phacoemulsification, and infusion volume during surgery. Endothelial cell loss was significantly less in the nuclear cracking group than in the undivided sculpting group. Ultrasound time in surgery with cracking was significantly shorter than that in surgery without cracking. The time for the phacoemulsification maneuvers and the infusion volume were the same for both procedures. These findings indicate that the ultrasound time was shortened using the nuclear cracking technique and resulted in less corneal injury.

Aged↗
PubMed1991

Eccentric capsulorhexis and bidirectional endocapsular phacoemulsification.

The advantages of continuous circular capsulorhexis and endocapsular (endolenticular, posterior chamber, in situ) phacoemulsification are well recognized. Perhaps the only disadvantage of the phacoemulsification technique is the increased operative time. This report presents a new method for endocapsular phacoemulsification which includes a superiorly decentered circular or oval capsulorhexis and more rapid endocapsular phacoemulsification using a combination of one- and two-handed techniques. The procedure may also be safer since most of the phacoemulsification is performed within the central "safe zone" of the posterior chamber.

Cataract Extraction↗
PubMed1991

Nucleus-splitting phacoemulsification technique.

A technique for phacoemulsification that can be used with or without capsulorhexis and that allows surgery to be performed at the 12 o'clock position is described. Following central sculpting, the nucleus is tipped superiorly to the level of the iris plane with a second instrument and the phacoemulsification tip. The hard nucleus is split from the soft nucleus, leaving two bowl-shaped pieces. The nucleus is rotated and the hard nucleus is removed with a phacoemulsification tip while the softer nucleus or epinucleus is ignored. Once the hard nucleus has been removed, the epinucleus follows easily into the phacoemulsification tip. The technique is advantageous for beginning phacoemulsification surgeons and offers an alternative for very hard nuclei with small pupils.

Cataract Extraction↗
PubMedDate not supplied

Cataract extraction by the intracapsular methods and by phacoemulsification: the results of surgeons in training.

The results of 63 phacoemulsifications performed by 14 resident ophthalmologists (surgeons in training) were compared to their first 112 intracapsular cataract procedures. Although the number of complications was greater in the eyes undergoing intracapsular operations, the final visual acuities obtained by either procedurewere similar: visual acuities in the range of 20/20 to 20/30 were found in 80.7% of intracapsular cataract operations and in 83.3% of phacoemulsification procedures. Visual acuities of 20/50 or better were found in 90.3% of intracapsular cataract extractions andin 88.8% of phacoemulsification procedures. Cylindric correction of higher power was required to correct astigmatism associated with intracapsular cataract surgery as compared to phacoemulsification. The results of irrigation-aspiration of soft or traumatic cataracts performed in 20 eyes with needle and syringe were compared to results of 19 eyes operated on by use of the Cavitron-Kelman irrigation-aspiration handpiece. The incidence of postoperative secondary membrane requiring discussion was similar for both procedures. The basis for setting up a successful program for resident training in phacoemulsification is discussed.

Cataract Extraction↗
PubMed1989

Phacoemulsification systems.

Our objectives in conducting this evaluation were to present an overview of a basic phacoemulsification system and its components, to describe the phacoemulsification procedure within the context of the operating principles of the system's components, and to compare two manufacturers' products. Specifications for additional phacoemulsification systems are available in the November 1989 edition of ECRI's Hospital Product Comparison System. Both of the evaluated systems enable a surgeon to perform a complete cataract extraction procedure by phacoemulsification. We rated both units Acceptable. In selecting a unit, users should consider performance, safety, human factors design, and manufacturer training and support. Although list prices vary widely among available systems, cost factors should not override clinical performance and safety requirements. While we measured certain engineering parameters, such as stroke length and ultrasound (US) output forces exerted on a medium, we stress that the results of these tests do not provide enough information to predict clinical performance. Clinical performance of phacoemulsification systems can be determined only by the experience of the clinicians who use them. Clinicians should review our evaluation thoroughly before making a purchasing decision. The information we present is useful for purchasing the evaluated or other available models because our criteria will guide users in assessing all components, and our findings and discussion on some aspects are common to many available systems (e.g., type of pump, irrigation and aspiration [I/A] characteristics). The in-depth clinical and technical information will help users to better understand principles, thereby helping them to better define their needs. Although we discovered a number of problems with the evaluated models, users should not assume that similar or other problems do not exist with systems that we did not evaluate. The willingness of manufacturers to cooperate in our studies and the knowledge they gain through participating may lead to the development of better products.

Cataract Extraction↗
PubMed1994

Phacoemulsification--a senior surgeon's learning curve.

We sought to prospectively document and evaluate the learning curve of an experienced extracapsular surgeon making a supervised transition from extracapsular cataract extraction (ECCE) to phacoemulsification. Over a period of 2 weeks, 51 phacoemulsification procedures using an endocapsular nucleofractis technique were performed by a single senior surgeon at the Christian Medical College in Vellore, India under the supervision of a visiting US expert with more than 15 years' experience in the technique. Vitreous loss occurred in seven eyes (six prior to the stage of cortical aspiration); failure of capsulorhexis necessitated conversion to standard ECCE in four. Injury to the inferior iris during phacoemulsification was cosmetically significant in three eyes. Two eyes had mild persistent localized corneal edema, but there were no instances of permanent corneal damage. One eye had intraoperative displacement of the nucleus into the vitreous. In one eye with vitreous loss, the implanted intraocular lens dislocated into the vitreous cavity. Two patients had clinically detectable cystoid macular edema at 6 weeks. Eleven patients were lost to follow up after 3 weeks. Six weeks after surgery, 36 of the remaining 40 eyes (90%) had achieved a best-corrected visual acuity of 6/6. We conclude that phacoemulsification requires supervised learning, even for an experienced surgeon. Complications still occurred, but were restricted to the unfamiliar steps of the surgery. Factors identified in the first 2 days of surgery (10 cases) as critical in the smooth transition to phacoemulsification were careful selection of initial cases, a successful capsulorhexis, and hydrodissection with vigorous nucleus mobilization.(ABSTRACT TRUNCATED AT 250 WORDS)

Astigmatism↗