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Results for “Phacoemulsification”

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PubMed1998

[Hard nucleus cataract extraction by phacoemulsification with intraocular lens implantation].

OBJECTIVE: To investigate the technique of phacoemulsification for hard nucleus cataract extraction and evaluate its therapeutic effects. METHODS: Three methods of phacoemulsification, the improved divide and conquer, the reserve lens cortex spin and no lens cortex spin, were performed on 62 eyes according to the type of nucleus hardness. RESULTS: With foldable or 5.5 mm PMMA intraocular lens implantation, the improved divide and conquer phacoemulsification was performed on 26 eyes, the reserve lens cortex spin phacoemulsification on 23 eyes and no cortex spin phacoemulsification on 13 eyes. At postoperative 3 days, 5 days and 30 days, the visual acuities without correction 0.5 or better were obtained respectively in 46 eyes (74.2%), 60 eyes (96.8%) and 61 eyes (98.4%). The major complications were corneal edema and posterior capsular rupture. CONCLUSION: The technique of phacoemulsification for hard nucleus cataract is worthy to be spread due to safety, easiness and minimum complication.

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PubMed2004

[Corneal endothelial damage and its repair after phacoemulsification].

OBJECTIVE: To introduce a grading system for corneal edema after phacoemulsification and to study the corneal endothelial damage and its repair after phacoemulsification. METHODS: One hundred and five senile cataracts after phacoemulsification were included. Corneal edema was categorized into grades 0 to 4. Endothelial densities at various locations of the cornea were measured with specular microscopy before and three months after surgery. RESULTS: The corneal endothelial cell loss rate was 4.6%, 14.9%, 40.8%, 67.0% and 84.4% in eyes with corneal edema from grades 0 to 4, respectively. Time required for resolution of corneal edema was (2.1 +/- 0.7) days (grade 1), (5.6 +/- 1.9) days (grade 2) and (21.8 +/- 7.1) days (grade 3). The endothelial cell densities at superior, mid and inferior portions of the cornea were (2006 +/- 546) cells/mm(2), (1979 +/- 545) cells/mm(2) and (1754 +/- 543) cells/mm(2) respectively at 3 months after phacoemulsification. Postoperative endothelial cell loss at superior, mid and inferior portions of the cornea was (627 +/- 496) cells/mm(2), (656 +/- 492) cells/mm(2) and (1026 +/- 509) cells/mm(2) respectively. The difference in postoperative endothelial cell densities between the superior and inferior portions of the cornea was statistically significant (P = 0.017), so was the difference between mid and inferior portions of the corneas (P = 0.027). There was no statistically significant difference between the superior and mid portions of the cornea (P = 0.867). CONCLUSION: The grading system for corneal edema is helpful in evaluating the severity of endothelial damage after phacoemulsification and can be used to predict the outcome of the cornea. The major area of endothelial injury after phacoemulsification occurs at the inferior portion of the cornea.

Aged↗

PubMedDate not supplied

Visual results and complications of posterior chamber intraocular lens implantation after capsular tear during phacoemulsification.

BACKGROUND AND OBJECTIVE: To determine the visual outcome and complications of posterior chamber intraocular lens implantation after capsular tear in patients undergoing phacoemulsification at Istanbul University, Istanbul Faculty of Medicine, Department of Ophthalmology, Istanbul, Turkey. PATIENTS AND METHODS: The medical records of patients who underwent phacoemulsification surgery for senile cataract from January 1, 1996, to December 31, 1998, were reviewed. Patient inclusion criteria were implantation of a posterior chamber intraocular lens after phacoemulsification, being operated on by one of two surgeons, and a follow-up of at least 1 year. There were 58 eyes in the group with capsular tear and 159 eyes in the group with intact capsule. RESULTS: A final visual acuity of 0.8 or more was more common in eyes with uncomplicated phacoemulsification surgery (chi-square = 16.25, P = .03). Refraction stabilized most commonly at 2 to 6 months postoperatively in patients with capsular tear and 1 to 21 days postoperatively in patients with uncomplicated phacoemulsification (chi-square = 22.61, P < .001). Complications such as retinal detachment (odds ratio = 11.70, P < .05), cystoid macular edema (odds ratio = 26.33, P < .01), increased intraocular pressure (odds ratio = 14.54, P < .05), and decentration of the intraocular lens (odds ratio = 32.79, P = .001) were more frequently observed in eyes with capsular tear. CONCLUSIONS: It takes longer for the refraction to stabilize in eyes with posterior chamber intraocular lens implantation after capsular tear during phacoemulsification. Complications such as retinal detachment, cystoid macular edema, increased intraocular pressure, and decentration of the intraocular lens are more common in these patients, and therefore they should be observed for a longer period of time.

Adult↗

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.

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PubMed1997

Temporal corneal phacoemulsification in filtered glaucoma patients.

PURPOSE: To evaluate the effect of temporal clear corneal phacoemulsification on intraocular pressure (IOP) in eyes that had prior trabeculectomy. DESIGN: Retrospective case-control study. PATIENTS: Forty consecutive patients (cases; TRAB-PHACO group) who underwent temporal corneal phacoemulsification subsequent to trabeculectomy were identified. Forty patients (controls; TRAB group) who had trabeculectomy alone were matched to the cases for length of follow-up, age, IOP, number of anti-glaucoma medications, number of 5-fluorouracil (5-FU) injections, race, sex and diagnosis. MAIN OUTCOME MEASURES: Comparison of IOP before and one year after phacoemulsification in the TRAB-PHACO group, and comparison with the TRAB group. Survival analysis of IOP control after trabeculectomy in the TRAB-PHACO and TRAB groups. RESULTS: In the TRAB-PHACO group, IOP one year after phacoemulsification was not significantly different from the pre-phacoemulsification IOP value (p = 0.65). Kaplan-Meier survival analysis showed that the rates of IOP control at 3, 6 and 9 years after trabeculectomy in the TRAB-PHACO group were 80%, 66% and 44%; in the TRAB group these were 79%, 69% and 55%. These survival curves were not statistically different (p = 0.55). CONCLUSIONS: Cataract surgery by temporal clear corneal phacoemulsification in eyes with filtering blebs after trabeculectomy does not adversely affect long term IOP control.

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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.

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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.

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PubMed2000

Effect of phacoemulsification surgery on hypotony following trabeculectomy surgery.

OBJECTIVE: To review the effect of phacoemulsification surgery in eyes with chronic hypotony following trabeculectomy with mitomycin C. DESIGN: Retrospective analysis of all eyes that underwent phacoemulsification surgery for symptomatic cataracts and had a preoperative diagnosis of chronic hypotony (intraocular pressure [IOP] </=6 mm Hg) for at least 6 months following trabeculectomy with mitomycin C. Each case had at least 6 months' follow-up after the phacoemulsification surgery. SETTING: A tertiary care referral center. INTERVENTION: Clear cornea phacoemulsification surgery, with minimal perioperative anti-inflammatory medication and retention of viscoelastic in eyes at case conclusion. MAIN OUTCOME MEASURES: Intraocular pressure, visual acuity, and complications. RESULTS: Nine eyes of 9 patients were identified. Mean preoperative IOP was 4. 2 +/- 1.4 mm Hg; the mean postoperative IOP was 7.3 +/- 2.8 mm Hg (P=.009). Intraocular pressure increased in all but 2 eyes. One of these 2 eyes experienced an acutely elevated IOP (34 mm Hg) on postoperative day 4, which dropped back to preoperative levels after trabeculectomy flap needling. Mean preoperative visual acuity was 20/300; mean postoperative visual acuity was 20/40. CONCLUSION: Phacoemulsification surgery may be associated with a statistically significant elevation in IOP in previously filtered eyes with hypotony, resulting in resolution of hypotony in some of these challenging cases. Arch Ophthalmol. 2000;118:763-765

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PubMed2002

[In vivo measurement of temperature during phacoemulsification].

BACKGROUND: Based on our experience of in vitro measurements of temperature in the anterior chamber in 1994 we designed a new spatula with an integrated probe that enabled us to measure temperature continuously during phacoemulsification without any surgical effort. METHODS: We measured the temperature in the anterior chamber during 50 cases of phacoemulsification. Depending on the indications, we used different energy modes (0-100%) and pulse modes ranging from 3 to 10 pulses per second or continuous ultrasonic output. Different viscoelastic substances were also used. RESULTS: The average temperature in the anterior chamber was 30 degrees C and adapted to the temperature of the irrigation fluid within seconds as soon as irrigation was started. During phacoemulsification each ultrasonic output causes an increase of temperature. In the case of continuous mode, the maximum rise in temperature was 3.5 degrees C. When the pulse mode was used the temperature increased up to 1.7 degrees C. It is important to note that one single pulse may increase the temperature by 0.8 degree C close to the phacotip. The rise of temperature correlated with the viscosity of the viscoelastic substance used. CONCLUSIONS: The new probe proved to be a practical device to monitor temperature in the anterior chamber during phacoemulsification. Up to now we did not encounter any critical degrees of temperature but it should be pointed out that a functional irrigation unit, the use of pulse mode or permanent ultrasonic output and in particular the type of viscoelastic material used are all important parameters influencing the rise of temperature during phacoemulsification. Further experience and results obtained with the new probe will be reported in the future.

Anterior Chamber↗

PubMed2006

A prospective randomized clinical trial of phacoemulsification vs manual sutureless small-incision extracapsular cataract surgery in Nepal.

PURPOSE: To compare the efficacy and visual results of phacoemulsification vs manual sutureless small-incision extracapsular cataract surgery (SICS) for the treatment of cataracts in Nepal. DESIGN: Prospective, randomized comparison of 108 consecutive patients with visually significant cataracts. METHODS: settings: Outreach microsurgical eye clinic. patients: One hundred eight consecutive patients with cataracts were assigned randomly to receive either phacoemulsification or SICS. intervention Cataract surgery with implantation of intraocular lens. main outcome measures: Operative time, surgical complications, uncorrected and best-corrected visual acuity (BCVA), astigmatism, and central corneal thickness (CCT). RESULTS: Both surgical techniques achieved excellent surgical outcomes with low complication rates. On postoperative day 1, the groups had comparable uncorrected visual acuity (UCVA) (P = 0.185) and the SICS group had less corneal edema (P = 0.0039). At six months, 89% of the SICS patients had UCVA of 20/60 or better and 98% had a best-corrected visual acuity (BCVA) of 20/60 or better vs 85% of patients with UCVA of 20/60 or better and 98% of patients with BCVA of 20/60 or better at six months in the phaco group (P = 0.30). Surgical time for SICS was much shorter than that for phacoemulsification (P < .0001). CONCLUSION: Both phacoemulsification and SICS achieved excellent visual outcomes with low complication rates. SICS is significantly faster, less expensive, and less technology dependent than phacoemulsification. SICS may be the more appropriate surgical procedure for the treatment of advanced cataracts in the developing world.

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PubMed2005

Ultrasonic power reduction during phacoemulsification using adjunctive NeoSoniX technology.

PURPOSE: To compare the phacoemulsification times and powers used in 3 phacoemulsification machine configurations. SETTING: Wolfe Eye Clinic, Marshalltown, Iowa, USA. METHODS: A randomized prospective study of 410 consecutive cases was conducted. All cases were performed using the Alcon Legacy 20000 phacoemulsification machine. Configurations were the Standard Legacy 20000 machine (n=165), Advantec upgraded Legacy 20000 (n=112), and Advantec upgraded Legacy 20000 with NeoSoniX (n=133). Preoperative measurements included the patient's age and cataract grade using the nuclear color (NC) scale of the Lens Opacities Classification System III (LOCS III). Intraoperative measurements included machine-measured phacoemulsification time and average percentage of maximum power expenditure. An independent statistician performed analysis of covariance on NC for each of the machine configurations. RESULTS: The mean age in years and the NC value were similar in each group. There was no significant difference in phacoemulsification time in minutes among the 3 machines: Standard=1.17, Advantec=1.12, NeoSoniX=1.16. The average percentage of maximum power consumption was similar for Standard Legacy 20000 at 38.00% and Advantec Legacy 20000 at 37.97% but significantly less for Advantec Legacy 20000 with NeoSoniX at 27.56% (P<.001). With the NeoSoniX-incorporated machine, compared with Standard and Advantec, a 27.5% reduction in ultrasonic energy power expenditure was observed all grades of nuclear density. CONCLUSIONS: The addition of 15% amplitude NeoSoniX rotational energy reduced total ultrasonic power expenditure by 27.5% for all cataract nuclear densities.

Humans↗

PubMed2005

Effect of preoperative counseling on patient fear from the visual experience during phacoemulsification under topical anesthesia: Multicenter randomized clinical trial.

PURPOSE: To determine whether preoperative counseling about potential intraoperative visual experience during phacoemulsification under topical anesthesia reduces fear in patients having cataract surgery. SETTING: The Eye Institute at Tan Tock Seng Hospital, Singapore, Royal Hull Hospitals NHS Trust, Kingston-upon-Hull, and Manchester Royal Eye Hospital, Manchester, United Kingdom. METHODS: In this prospective multicenter randomized clinical trial, patients with cataracts having elective phacoemulsification under topical anesthesia were recruited and randomized into 2 groups. Both groups received routine preoperative counseling regarding risks and benefits of cataract surgery. One group received additional counseling on the potential intraoperative visual experience during phacoemulsification; the other group did not. The patients were then interviewed within 24 hours following phacoemulsification regarding their intraoperative experience. RESULTS: Two hundred nineteen patients were recruited over an 11-month period. There were 104 men and 115 women. The mean age was 68 years (range 20 to 89 years). There were 188 Singaporeans, comprising 168 Chinese, 13 Malays, and 7 Indians, and 31 British patients, all of whom were white. The mean fear score was 0.3 in the group that received additional counseling and 0.9 in the group that did not receive additional counseling (P = .036). The effect of counseling on fear was significant (P = .002) even after controlling for sex, age, and whether first or second cataract surgery. CONCLUSIONS: Preoperative counseling about the potential intraoperative visual experience during phacoemulsification under topical anesthesia helped to reduce the fear from the visual sensations in patients having cataract surgery.

Adult↗

PubMed2006

Subjective difficulty of each stage of phacoemulsification cataract surgery performed by basic surgical trainees.

PURPOSE: To measure the relative difficulty of each stage of phacoemulsification surgery performed by basic surgical trainees. SETTING: Mater Misericordiae University Hospital, Dublin, Ireland. METHODS: This prospective study comprised 100 consecutive cases of phacoemulsification performed by 8 trainee surgeons over an 11-month period. The trainees completed a questionnaire at the end of surgery, rating the degree of difficulty of 8 individual stages of phacoemulsification on a 5-point scale from 1 (very easy) to 5 (very difficult). RESULTS: At the start of the study, trainees had spent a mean of 9.4 months training. The mean preoperative best corrected decimal visual acuity was 20/70. The most difficult stages were phacoemulsification and capsulorhexis with the highest mean scores of 3.32 +/- 1.00 (SD) and 3.30 +/- 1.24, respectively and the lowest completion rates of 66.7% and 74.4%, respectively. The first 3 stages of peribulbar blockade (1.72 +/- 0.75), draping the surgical field (1.35 +/- 0.70) and corneal incision (1.97 +/- 0.72) were easiest and had close to a 100% completion rate. Hydrodissection, irrigation/aspiration, and intraocular lens insertion had difficulty rates of 2.42 +/- 0.92, 2.80 +/- 1.10, and 2.58 +/- 1.08, respectively, and completion rates of 92.3%, 78.4%, and 83.1%, respectively. Posterior capsule tear occurred in 9%, including 4% with vitreous loss; there was 1 case of zonular dehiscence. CONCLUSIONS: Trainee surgeons found phacoemulsification and capsulorhexis the most difficult stages of cataract surgery early in the learning curve. More time can be dedicated to mastering these steps in the wet lab.

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PubMed2006

Incidence and outcomes evaluation of endophthalmitis management after phacoemulsification and 3-piece silicone intraocular lens implantation over 6 years in a single eye unit.

PURPOSE: To evaluate the incidence and outcomes of management of endophthalmitis following phacoemulsification and 3-piece silicone intraocular lens (IOL) implantation in a single eye unit over a 6-year period. SETTING: Shrewsbury and Telford Hospital, NHS Trust, Shrewsbury, United Kingdom. METHODS: Forty-four cases of endophthalmitis following phacoemulsification and 3-piece silicone IOL implantation were identified between January 1, 1998, and December 31, 2003. All the data related to the endophthalmitis cases were prospectively collected. The total number of cataract surgeries was identified from the hospital information technology department through coding data. RESULTS: There were 44 cases of endophthalmitis following 12 362 phacoemulsification cataract extractions (incidence 0.36%). The incidence of endophthalmitis with a silicone polypropylene IOL (0.67%) was significantly higher (P<.0005) than with a silicone poly(methyl methacrylate) (PMMA) IOL (0.24%). Thirty-six patients (81.8%) had vitreous tap while 8 patients (18.2%) had vitrectomy. Twenty cases (45.5%) were culture positive. Visual acuity was 6/12 or better in 30 patients (68.8%). There was weak correlation between visual acuity at presentation and final visual outcome (Pearson correlation r = 0.33, P = .029). Final visual acuity was not significantly related to culture results (P = .85, Mann-Whitney U test) or type of presentation (P = .52, Mann-Whitney U test). CONCLUSIONS: In this first single-center study to report incidence of endophthalmitis following phacoemulsification and silicone IOL implantations alone, the incidence of endophthalmitis was significantly higher with silicone polypropylene IOLs than with silicone PMMA IOLs and the overall incidence of endophthalmitis following phacoemulsification surgery was higher than most of the published data.

Anti-Bacterial Agents↗

PubMed2006

Phacoemulsification tip vacuum pressure: Comparison of 4 devices.

PURPOSE: To determine the vacuum pressure generated by 4 phacoemulsification devices measured at the phacoemulsification tip. SETTING: University ophthalmology department. METHODS: The effective vacuum pressures generated by the Sovereign (AMO), Millennium (Bausch & Lomb), Legacy AdvanTec (Alcon Laboratories), and Infiniti (Alcon Laboratories) phacoemulsification machines were measured with a device that isolated the phacoemulsification tip in a chamber connected to a pressure gauge. The 4 machines were tested at multiple vacuum limit settings, and the values were recorded after the foot pedal was fully depressed and the pressure had stabilized. The AdvanTec and Infiniti machines were tested with and without occlusion of the Aspiration Bypass System (ABS) side port (Alcon Laboratories). The Millennium machine was tested using venturi and peristaltic pumps. RESULTS: The machines generated pressures close to the expected at maximum vacuum settings between 100 mm Hg and 500 mm Hg with few intermachine variations. There was no significant difference between pressures generated using 19- or 20-gauge tips (Millennium and Sovereign). The addition of an ABS side port decreased vacuum by a mean of 12.1% (P < .0001). CONCLUSION: Although there were some variations in vacuum pressures among phacoemulsification machines, particularly when an aspiration bypass tip was used, these discrepancies are probably not clinically significant.

Phacoemulsification↗

PubMed2006

Alteration of free radical development by ophthalmic viscosurgical devices in phacoemulsification.

PURPOSE: To determine the effect of ophthalmic viscosurgical devices (OVDs) and irrigation/aspiration (I/A) settings on free radical development during phacoemulsification. SETTING: Department of Ophthalmology, Nippon Medical School, Tokyo, Japan. METHODS: Free radicals were detected by the electron spin resonance (ESR) spin-trap method. After a spin-trapping agent, 5,5-dimethyl-1-pyrroline N-oxide 1%, was mixed with the irrigating solution, phacoemulsification simulation was performed in an eye model at 100% ultrasound power levels for 10, 20, and 30 seconds. A high I/A setting (35 mL/min with 250 mm Hg vacuum) and a low I/A setting (15 mL/min with 60 mm Hg vacuum) were used in combination with no OVD, sodium hyaluronate 1% (Healon), sodium hyaluronate 2.3% (Healon5), sodium hyaluronate 3%-chondroitin sulfate 4% (Viscoat), or sodium hyaluronate 1% (Opegan). Immediately after phacoemulsification, the solution in the anterior chamber was collected and signals from the spin adduct were measured using an ESR spectrometer. RESULTS: With the low setting, all OVDs significantly suppressed the signals for up to 20 seconds. At 30 seconds, the signals were still significantly smaller in all OVD groups, except Healon, than those in the no-OVD. With the high setting, the effect was not significant in the Healon and Opegan groups at 10 seconds; by 20 seconds and after, only Viscoat showed significant suppression. CONCLUSIONS: Free radical development in phacoemulsification can be altered by OVD properties and I/A settings. To reduce oxidative stress to the corneal endothelium, attention should be paid to the retention of OVDs in the anterior chamber during phacoemulsification.

Animals↗

PubMed2006

Torque and flattening effects of clear corneal temporal and on-axis incisions for phacoemulsification.

PURPOSE: To compare the torque and flattening effect induced by temporal or on-axis clear corneal incisions (CCIs) for phacoemulsification. SETTING: Moorfields Eye Hospital, London, United Kingdom. METHODS: Randomized controlled clinical trial on 62 eyes with cataract and mild to moderate corneal astigmatism (<2.60 diopters [D]) having phacoemulsification with a temporal CCI (temporal group) or on-axis CCI (on-axis group). Corneal astigmatism was assessed by corneal topography preoperatively and 3 weeks after surgery. The meridian of the incisions was marked on the cornea before local anesthesia was given to avoid anesthesia-related cyclotorsion. The surgically induced astigmatism (SIA) vector, torque, flattening effect, and accuracy of incision placement were analyzed in the 2 groups and compared with a paired t test. RESULTS: Three weeks after surgery, the on-axis CCI induced slightly more flattening of the meridian of the incision (mean -0.63 +/- 0.57 D [SD]) than the temporal CCI (mean -0.50 +/- 0.44 D); however, the differences were not statistically significant (P = .31). Simple algebraic difference showed a mean increase in astigmatism magnitude of 0.12 +/- 0.52 D in the temporal group and a mean reduction of 0.21 +/- 0.53 D in the on-axis group (P = .02). The mean absolute torque was 0.28 +/- 0.27 D and 0.53 +/- 0.37 D, respectively (P<.005). The absolute angle of error of incision placement (alpha) was greater after on-axis CCIs (mean 25.9 +/- 20.1 degrees) than after temporal CCIs (mean 14.5 +/- 14.3 degrees) (P = .01). CONCLUSIONS: In eyes with preoperative astigmatism less than 2.60 D, on-axis CCI phacoemulsification induced slightly more flattening along the incision meridian than temporal CCI phacoemulsification, although the differences were not significant. The on-axis CCI was associated with significantly greater absolute torque and angle of error than the temporal CCI. These factors could limit the benefit of placing the incision on axis when the aim is to reduce preoperative astigmatism in phacoemulsification.

Aged↗

PubMed2004

Effect of cataract surgery on the corneal endothelium: modern phacoemulsification compared with extracapsular cataract surgery.

PURPOSE: To investigate whether modern phacoemulsification surgery results in more damage to the corneal endothelium than extracapsular cataract extraction (ECCE), and to examine which preoperative, operative, and postoperative factors influence the effect of cataract surgery on the endothelium. DESIGN: Randomized controlled trial. PARTICIPANTS: Five hundred patients 40 years or older were randomized into 2 groups (ECCE, 249; phacoemulsification, 251). METHODS: Central corneal endothelial cell counts, coefficient of variation of cell size, and hexagonality were assessed before surgery and up to 1 year postoperatively. MAIN OUTCOME MEASURE: Endothelial cell count. RESULTS: Four hundred thirty-three patients completed the trial. The initial preoperative mean cell count for the entire sample was 2481 (standard error [SE]: 18.6), reduced at 1 year postoperatively to 2239 (SE: 23.5). An average 10% reduction in cell count was recorded by 1 year postoperatively. There was no such change in hexagonality or in the coefficient of variation. There was no significant difference in overall percentage cell loss between the 2 treatment groups. Factors associated with excessive cell loss (> or =15% by 1 year) were a hard cataract (odds ratio [OR]: 2.1, 95% confidence limits: 1.1-4.1; P = 0.036), age (OR: 1.04, P = 0.005), and capsule or vitreous loss at surgery (OR: 2.38, P = 0.106). Phacoemulsification carried a significantly higher risk (OR: 3.7, P = 0.045) of severe cell loss in the 45 patients with hard cataracts relative to ECCE (52.6% vs. 23.1%; chi-square test, P = 0.041), with both procedures achieving similar postoperative visual acuity outcomes. CONCLUSIONS: No significant difference in overall corneal endothelial cell loss was found between these 2 operative techniques. The increased risk of severe cell loss with phacoemulsification in patients with hard cataracts suggests that phacoemulsification may not be the optimal procedure in these cases, and that ECCE should be preferred.

Adult↗