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Results for “Phacoemulsification”

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PubMed1999

Ultrasonographic classification and phacoemulsification of white senile cataracts.

OBJECTIVE: To classify the white senile cataracts and report the results of phacoemulsification of white cataracts. DESIGN: Prospective, noncomparative case series. PARTICIPANTS: One hundred eyes were included. INTERVENTION: White cataracts were examined biomicroscopically before surgery, and their acoustic structure was analyzed with standardized A-scan echography. White cataract surgery was performed with phacoemulsification via a superior temporal near-limbus corneal approach using a bimanual divide-and-conquer or stop-and-chop technique. Patients were followed after surgery for a period of 9 months. MAIN OUTCOMES MEASURES: The A-scan acoustic structure of white cataracts; successful accomplishment of capsulorrhexis; mean phacoemulsification time, power, and energy; intraoperative and postoperative complications of phacoemulsification; and visual acuity at 9 months after surgery. RESULTS: White senile cataracts were categorized into three different types. Type I included intumescent, white cataracts with cortex liquefaction and high internal acoustic reflections (44 eyes), type II included white cataracts with voluminous nuclei, little amount of whitish solid cortex, and low internal acoustic reflections (49 eyes), and type III included white cataracts with fibrosed anterior capsule and low internal echospikes (7 eyes). Circular capsulorrhexis was completed in 79 eyes and was significantly less successful in eyes with type I intumescent, white cataracts compared with type II white cataracts (P = 0.0034). Mean phacoemulsification time and energy were higher in type II and type III white cataracts. Posterior capsule rupture occurred in ten eyes, and three of these eyes were complicated by vitreous loss. In 95 eyes, the posterior chamber lens was implanted in the capsular bag and in five eyes in the sulcus. After surgery, a transient corneal edema developed in 31 eyes. At the final 6-month examination, the mean postoperative visual acuity was 20/30. CONCLUSION: Current phacoemulsification techniques can safely manage eyes with senile white cataracts. The increased risk of difficulty with continuous capsulorrhexis in type-I and type-III white cataracts and the substantial nuclear hardness in type-II and mainly type-III white cataracts would suggest that current phacoemulsification techniques might not be as successful in these patients as they are in ordinary earlier cataracts.

Aged↗

PubMed2001

Phacoemulsification conditions resulting in thermal wound injury.

PURPOSE: To determine and model the relationships between phacoemulsification conditions and viscoelastic agents that result in thermal wound injury. SETTING: Animal laboratory, Irvine, California, USA. METHODS: Mechanical and animal models, various wound sizes, phacoemulsification tips, and dispersive and cohesive viscoelastic agents were evaluated. Settings for phaco power, vacuum, and irrigation levels were controlled within a surgically relevant range. In the mechanical and animal models, incision temperature was assessed as a function of phacoemulsification parameters and time. In the animal model, wound damage was evaluated at the time of surgery. RESULTS: Induced time delays from the onset of phaco power to the onset of irrigation flow caused a thermal rise at the incision site. In these experiments, lack of irrigation and aspiration resulted in the greatest thermal rise and caused wound damage. Both the cohesive and dispersive viscoelastic agents were associated with a delay in the start of irrigation and aspiration, which resulted in similar maximum temperatures. Mathematical models were developed to estimate the maximum incision temperature from the phacoemulsification power, the duration (seconds) of occlusion, the tip gauge and type, and other phacoemulsification parameters. The models predict that under comparable conditions, occlusion with a viscoelastic agent will result in higher incision temperatures than occlusion with a balanced salt solution. CONCLUSION: Under comparable phacoemulsification conditions, both the cohesive and dispersive viscoelastic agents were associated with elevated temperatures that would be preventable by ensuring irrigation and aspiration flow before the onset of phacoemulsification power.

Acetates↗

PubMed1998

Conversion from phacoemulsification to extracapsular cataract extraction: incidence, risk factors, and visual outcome.

PURPOSE: To evaluate the incidence, risk factors, and visual outcome in cases converted from phacoemulsification to routine extracapsular cataract extraction (ECCE). SETTING: Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India. METHODS: A retrospective study was performed in 540 eyes that had clear corneal phacoemulsification performed by an experienced phacoemulsification surgeon. The cases in which phacoemulsification was initiated and then converted to ECCE were studied. The main parameters evaluated were the factors responsible for the conversion, corneal endothelial cell loss, and visual outcome. RESULTS: Twenty eyes (3.7%) required conversion to ECCE during phacoemulsification. Pupillary miosis (6 cases), posterior capsule rupture (5 cases), prolonged phaco time (4 cases), posterior extension of the capsulorhexis (2 cases), corneal thermal burn (1 case), subluxation of the lens (1 case), and malfunctioning of the ultrasonic handpiece (1 case) were the reasons for the conversion. The mean percentage of endothelial cell loss was 11.06% +/- 2.3 (SD); 18 cases (90.0%) achieved a visual acuity of 20/40 or better at 6 weeks. CONCLUSIONS: Intraoperative pupillary miosis, posterior capsule rupture, and very hard nuclear cataract causing prolonged phacoemulsification were the major risk factors for conversion to ECCE. Optimal preoperative preparation and prompt recognition of complications during phacoemulsification can lead to timely conversion to ECCE to achieve a good visual outcome.

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PubMed1996

Phacoemulsification in diabetics.

In a retrospective study we examined a consecutive group of diabetic patients (74 operated eyes) who underwent phacoemulsification and intraocular lens implantation over a 2 year period ending in June 1994. We compared this group with 66 diabetic eyes who underwent extracapsular surgery and lens implantation and who were examined for a previous study. There were no significant differences in progression of the retinopathy, complications, or final visual acuity. Seventy-two per cent of the phacoemulsification group improved by at least 2 lines of Snellen acuity postoperatively compared with 76% of the extracapsular group. Seventy-four per cent of the phacoemulsification group achieved an acuity of 6/12 or better compared with 68% of the extracapsular group. Overall there were fewer post-operative complications in the phacoemulsification group though there was an increased incidence of transient corneal oedema. The major cause of poor visual acuity in the phacoemulsification group was maculopathy, particularly in the presence of proliferative retinopathy in older patients. Use of a small intraocular lens did not prevent adequate fundal examination or photocoagulation. It is concluded that the outcome of cataract surgery in diabetics is largely determined by the degree of maculopathy. Phacoemulsification and extracapsular cataract surgery give similar visual results. Diabetic retinopathy should not be considered a contraindication to small-incision cataract surgery and phacoemulsification.

Adult↗

PubMed1999

[Erbium laser phacoemulsification--a clinical pilot study].

INTRODUCTION: From August 1997 to March 1998, we performed a prospective pilot study to examine erbium laser phacoemulsification in cataract surgery under clinical conditions and to determine the side effects of this method. PATIENTS AND METHOD: 34 patients (40 eyes) with senile cataract were recruited. Slit lamp findings, keratometry, best corrected visual acuity, refraction, pachymetry, endothelial cell count and intraocular pressure were determined preoperatively and on 1st, 4th, 14th and 60th postop day according to a standardised protocol (single pulse energy between 10 and 20 mJ, frequency of application 60 Hz, average phaco time 3 min, total energy 38.5 mJ). The operations were done with the erbium laser system MCL 29, Aesculap-Meditec Co., Jena, Germany. RESULTS: A total emulsification of the nucleus was possible in 36 of 40 eyes (90%) (nucleus hardness between 0 and 3). A partial emulsification of the nucleus in nucleus hardness 3 was possible in 2 eyes, in nucleus hardness 4 in 1 eye and in nucleus hardness 2 in 1 eye (4 eyes--10%). Visual acuity increased from 0.3 preop to 0.8 two months postop (median). Intraocular pressure decreased from 16 mm Hg preoperatively to 13 mm Hg two months postoperatively (median). The increase of corneal thickness was not statistically significant compared to baseline. The decrease of endothelial cell count was 0.96%. Postoperative complications which are not known in ultrasonic phacoemulsification did not appear in erbium laser phacoemulsification. CONCLUSION: Erbium laser phacoemulsification is a surgical method that makes the emulsification of softer nuclei under clinical conditions possible with a low rate of complications also in the beginning of the learning curve. For higher nucleus hardnesses, technical and surgical parameters have to be optimised. Advantages of erbium laser phacoemulsification compared to ultrasonic phacoemulsification are less energy transmission into the eye, no heating of anterior chamber, impossibility of corneal burns and easier access in eyes that are deep into the orbit. Especially advantageous is the high protection of endothelium by erbium laser phacoemulsification. A prospective controlled comparative study to ultrasonic emulsification is desirable.

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PubMed2006

Thermography used for analysis and comparison of different cataract surgery procedures based on phacoemulsification.

Thermography has been employed to analyze and compare three cataract surgery procedures performed in vivo with phacoemulsification, namely, the Sovereign phacoemulsification system with a traditional technique, the Sovereign WhiteStar phacoemulsification system with a traditional technique and the Sovereign WhiteStar phacoemulsification system with a bimanual technique. During the entire surgical procedure, the temperature of the ocular surface was monitored. The temperature values in the area where the phaco probe was inserted in the eye were measured, and the quantities of heat transmitted to the eye in the different procedures were assessed through suitable indices. In this study the highest temperature measured for each procedure during the surgical operation was 44.9 degrees C for the Sovereign phacoemulsification system with a traditional technique, 41 degrees C for the Sovereign WhiteStar phacoemulsification system with a traditional technique and 39.5 degrees C for the Sovereign WhiteStar phacoemulsification system with a bimanual technique, which is also the surgical procedure having the lowest thermal impact on the eye, i.e., the one in which the temperature peaks are lowest in amplitude and the least amount of heat is transmitted to the eye. Thermography, used in this study as a temperature monitoring instrument, has allowed analysis to be effected through a useful and advantageous methodology, totally non-invasive as regards both surgeon and patient, and has been applied in vivo without requiring any change in the surgical procedure.

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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↗

PubMed2006

Time series analysis of age related cataract hospitalizations and phacoemulsification.

BACKGROUND: Cataract surgery remains a commonly performed elective surgical procedure in the aging and the elderly. The purpose of this study was to utilize time series methodology to determine the temporal and seasonal variations and the strength of the seasonality in age-related (senile) cataract hospitalizations and phacoemulsification surgeries. METHODS: A retrospective, cross-sectional time series analysis was used to assess the presence and strength of seasonal and temporal patterns of age-related cataract hospitalizations and phacoemulsification surgeries from April 1, 1991 to March 31, 2002. Hospital admission rates for senile cataract (n = 70,281) and phacoemulsification (n = 556,431) were examined to determine monthly rates of hospitalization per 100,000 population. Time series methodology was then applied to the monthly aggregates. RESULTS: During the study period, age-related cataract hospitalizations in Ontario have declined from approximately 40 per 100,000 to only one per 100,000. Meanwhile, the use of phacoemulsification procedures has risen dramatically. The study found evidence of biannual peaks in both procedures during the spring and autumn months, and summer and winter troughs. Statistical analysis revealed significant overall seasonal patterns for both age-related cataract hospitalizations and phacoemulsifications (p < 0.01). CONCLUSION: This study illustrates the decline in age-related cataract hospitalizations in Ontario resulting from the shift to outpatient phacoemulsification surgery, and demonstrates the presence of biannual peaks (a characteristic indicative of seasonality), in hospitalization and phacoemulsification during the spring and autumn throughout the study period.

Aging↗

PubMedDate not supplied

Comparison of the thermal effect on clear corneal incisions during phacoemulsification with different generation machines.

BACKGROUND AND OBJECTIVE: Older generation phacoemulsification units are widely employed where economics do not permit frequent upgrades. Thermal effects on the cornea while performing phacoemulsification with different generation machines were evaluated. PATIENTS AND METHODS: The thermal effect on the clear corneal incision during uncomplicated phacoemulsification performed by the Series 10,000 (Alcon Laboratories, Fort Worth, TX) and the Diplomax (Allergan, Irvine, CA) machines was clinically evaluated and correlated with the effective phacoemulsification time required. The clinical outcome was analyzed with respect to wound closure and surgically induced corneal astigmatism. RESULTS: The average effective phacoemulsification time required to emulsify a grade IV cataract was 88.33 +/- 15.81 seconds with the Series 10,000 machine and 61.67 +/- 21.79 seconds with the Diplomax machine. A grade 2 or more thermal effect was seen in 19.33% of patients operated on with the Series 10,000 machine and 3.22% of patients operated on with the Diplomax machine. The resultant tissue retraction affected wound closure and mean surgically induced corneal astigmatism (1.71 +/- 1.05 D with the Diplomax machine and 2.21 +/- 1.32 D with the Series 10,000 machine). CONCLUSIONS: Newer generation machines require less phacoemulsification power to emulsify hard cataracts, and the clinical outcomes are more favorable. Incision burns must be kept in mind when working with older generation phacoemulsification machines.

Adult↗

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.

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PubMed2004

Phacoemulsification after retinal detachment surgery.

PURPOSE: To evaluate the outcomes of phacoemulsification in eyes that had previous retinal detachment (RD) surgery. SETTING: Hayashi Eye Hospital, Fukuoka, Japan. METHODS: Ninety-six eyes of 90 consecutive patients who had phacoemulsification after previous RD surgery (RD group) were included. Fifty-one fellow eyes that had not had RD surgery but did have phacoemulsification served as controls (control group). Recurrence of RD, visual acuity, complications, and the neodymium:YAG (Nd:YAG) laser capsulotomy rate were examined. RESULTS: Recurrent RD after phacoemulsification occurred in 2 eyes (2.1%) in the RD group. Three eyes (5.9%) in the control group developed RD postoperatively. The incidence of RD was not significantly different between the 2 groups (P =.3416). The mean final visual acuity in the RD group was 20/30, significantly worse than in the control group (P =.0099). Posterior capsule opacification developed in 29 eyes (30.2%) in the RD group and 11 eyes (21.6%) in the control group; the difference between the groups was not significant. Eighteen eyes (43.9%) that had implantation of a poly(methyl methacrylate) (PMMA) intraocular lens (IOL) and 7 eyes (6.6%) that received an acrylic IOL had an Nd:YAG capsulotomy; the capsulotomy rate was significantly higher in eyes with a PMMA IOL than in eyes with an acrylic IOL (P<.0001). CONCLUSIONS: The rate of recurrent RD after phacoemulsification in eyes that had previous RD surgery was similar to that of new occurrence of RD in fellow eyes without RD before phacoemulsification. Because the Nd:YAG capsulotomy rate was lower in eyes with acrylic IOLs than in eyes with PMMA IOLs, acrylic IOLs are recommended for eyes at high risk for RD.

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PubMed2006

In vitro behavior of ophthalmic viscosurgical devices during phacoemulsification.

PURPOSE: To evaluate the behavior and aspiration of several ophthalmic viscosurgical devices (OVDs) during phacoemulsification. SETTING: Department of Ophthalmology, Tokyo Dental College Suidobashi Hospital, Tokyo, Japan. METHODS: Cohesive OVDs (sodium hyaluronate 1.0% [Healon and Provisc]), dispersive OVDs (sodium hyaluronate 3.0%-chondroitin sulfate 4.0% [Viscoat]), and new-generation OVDs such as viscoadaptive (sodium hyaluronate 2.3% [Healon5]) and viscodispersive (hyaluronic acid 1.65%-chondroitin sulfate 4.0% [DisCoVisc]) OVDs, were stained with fluorescein sodium. The movement of the OVDs during simulated cataract surgery was recorded in porcine eyes under an operating microscope and with a side-view video camera. The initial and complete aspiration times of each OVD during phacoemulsification using 20 and 40 mL/min flow rates and sleeves and the removal times using the irrigation and aspiration (I/A) tip at the end of surgery were evaluated from the recorded videos. RESULTS: The complete aspiration time of the cohesive OVDs was less than 3 seconds but up to 20 seconds with a low flow rate of 20 mL/min with a smaller sleeve. Other OVDs remained in the anterior chamber during phacoemulsification with both flow rates. The removal time for cohesive OVDs was less than 4 seconds and for new-generation OVDs, 10 to 15 seconds. The dispersive OVD required a significantly (P<.05) longer removal time than other OVDs. CONCLUSIONS: Cohesive OVDs are removed easily during phacoemulsification; however, the aspiration rate can be affected by fluidics. New-generation OVDs, such as Healon5 and DisCoVisc, remained in the anterior chamber during phacoemulsification and were removed easily by I/A at the end of surgery. The behavior of these OVDs is preferable during phacoemulsification.

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PubMed2004

Computer-simulated phacoemulsification.

OBJECTIVE: To develop a simulator for training in phacoemulsification to be used as a learning device for both beginners and experienced surgeons to shorten the learning curve. DESIGN: Experimental study. METHODS: The system consists of a personal computer, a 3-dimensional visual interface, a phacoemulsification handpiece, and a nucleus manipulator and foot pedals for control of the phacoemulsification procedure and microscope adjustments. The simulation is based on generalized simulation software that can be also used for the development of other medical simulations. MAIN OUTCOME MEASURES: Qualitative statements given in a questionnaire. Medical students and ophthalmic surgeons with varying experience of phacoemulsification were tested. RESULTS: A simulator for training in phacoemulsification has been developed. The surgical procedures can be practiced any number of times, and there is no risk to patients. The efforts of the surgeon can be evaluated objectively. CONCLUSIONS: Studies have shown that the number of complications for an ophthalmic surgeon learning phacoemulsification decreases exponentially, reaching close to the asymptote only after several hundred procedures. Simulator training might shorten the learning period, reduce expensive supervision by an experienced surgeon, and maintain and improve the skills of experienced surgeons.

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PubMed2004

Effect of temporal corneal phacoemulsification on intraocular pressure in eyes with prior trabeculectomy with an antimetabolite.

OBJECTIVE: To evaluate the effect of temporal corneal phacoemulsification on intraocular pressure (IOP) in eyes after primary trabeculectomy with intraoperative fluorouracil (5-FU) or mitomycin C (MMC). DESIGN: Retrospective case-control study. PATIENTS: Twenty-nine patients who were participants in a prospective randomized double-masked trial comparing the efficacies of intraoperative 5-FU and MMC and who underwent temporal corneal phacoemulsification after the primary trabeculectomy were matched to 29 patients enrolled in the same study who did not undergo cataract surgery. The 2 groups were matched for length of follow-up after the trabeculectomy and the antimetabolite used at the time of trabeculectomy. METHODS: Comparisons of IOP, visual acuity (VA), and the number of glaucoma medications were made between the 2 groups and within the groups at various follow-up intervals to detect any statistically significant differences. MAIN OUTCOME MEASURES: Intraocular pressure before phacoemulsification and at various times postoperatively were compared with IOP in the control group at the matched follow-up times. RESULTS: The mean of all IOP measurements beyond 3 months after phacoemulsification for each subject was significantly higher than the prephacoemulsification IOP (11.8+/-4.2 vs. 8.7+/-4.5 mmHg; P = 0.00003, paired t test). In contrast, the mean IOP remained stable in the control group during the equivalent time period (9.6+/-3.5 vs. 9.1+/-3.1 mmHg; P = 0.42, paired t test). Postphacoemulsification IOP was significantly higher than the corresponding IOP in the time-matched control group (P<0.003, analysis of covariance). Mean VA improved significantly after the phacoemulsification (P = 0.0002) but remained stable in the control group. CONCLUSION: Temporal corneal phacoemulsification can affect long-term IOP control after trabeculectomy with 5-FU or MMC.

Adult↗

PubMed2002

Acoustic cavitation in phacoemulsification: chemical effects, modes of action and cavitation index.

High-intensity ultrasound (US) energy (HIUE) has been extensively used in the last 3 decades in a wide range of surgical procedures, including phacoemulsification. The generation of radicals and sonoluminescence (SL) by application of continuous-wave (CW) HIUE to an aqueous medium under conditions simulating cataract phacoemulsification surgery is demonstrated by electron paramagnetic resonance (EPR) spectroscopy and a sensitive photon-detecting system. The findings provide direct evidence for the generation of acoustic cavitation in the simulated intraocular environment, pointing out that generation of acoustic cavitation in clinical phacoemulsification and other surgical applications of US is possible. The findings imply that the effects of acoustic cavitation in aqueous medium may contribute to the endothelial damage observed clinically following phacoemulsification cataract surgery. Saturation of the irrigating solution with various gases modifies the acoustic cavitation. Saturation of the irrigating solution with CO2 practically eliminates acoustic cavitation, with the concomitant elimination of radicals and SonL. CO2 may be utilized clinically to suppress acoustic cavitation in phacoemulsification and other medical applications. A cavitation index (CI) is introduced for the purpose of standardizing phacoemulsification instrumentation and other medical US devices that employ HIUE.

Acoustics↗

PubMed2001

Phacoemulsification combined with silicone oil removal through a posterior capsulorhexis.

PURPOSE: To evaluate the technique of silicone oil removal through a posterior capsulorhexis combined with phacoemulsification and intraocular lens (IOL) implantation. SETTING: Dr. Rajendra Prasad Center for Ophthalmic Sciences, New Delhi, India. METHODS: Fifteen eyes of 15 patients had phacoemulsification with removal of silicone oil, which had been used for intraocular tamponade after a previous pars plana vitrectomy. Eyes with a stable retina were included in the series. In all eyes, the silicone oil was removed through a planned posterior capsulorhexis after phacoemulsification. The parameters evaluated were the primary diagnosis, duration between silicone oil instillation and phacoemulsification, type of cataract, preoperative and postoperative best corrected visual acuities (BCVAs), and complications such as frequency of retinal redetachment and secondary cataract. RESULTS: Vitreoretinal surgery with silicone oil instillation was performed for rhegmatogenous-tractional detachment resulting from Eales' disease in 6 eyes and from proliferative diabetic retinopathy in 2 eyes, for primary rhegmatogenous retinal detachment in 6 eyes, and for traumatic rhegmatogenous detachment in 1 eye. The mean duration between the silicone oil instillation and phacoemulsification was 7.5 months +/- 3.8 (SD). Fourteen eyes had posterior subcapsular cataract, and 10 had nuclear sclerosis. Preoperative BCVA was worse than 6/60 in all eyes. The BCVA was 6/60 or better in 9 eyes after a minimum follow-up of 6 months. Two eyes had choroidal detachment in the early postoperative period. No eye had vitreous hemorrhage, retinal redetachment, secondary cataract, clinically significant endothelial decompensation or macular edema, or a dislocated IOL. CONCLUSION: The results indicate that silicone oil removal through a posterior capsulorhexis during phacoemulsification is a viable option and can be performed in selected cases of cataract with previous silicone oil instillation and a stable retina.

Adolescent↗

PubMed2002

Endothelial protection: avoiding air bubble formation at the phacoemulsification tip.

PURPOSE: To investigate the conditions under which bubbles form during phacoemulsification. SETTING: Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea. METHODS: In the first part of the study, the partial pressure of oxygen (pO(2)) was used as a surrogate measure for the partial pressure of air. Irrigation solutions packaged in glass and plastic containers were studied. A directly vented glass bottle was also tested. The pO(2) of the various irrigation solutions was measured as the containers were emptied. In the second part, phacoemulsification procedures were performed in rabbit eyes with different power settings and different irrigation solutions. Intracameral bubble formation during the procedure was recorded. Following the phacoemulsification procedures, the corneas were stained for F-actin and examined for endothelial injury. RESULTS: The initial pO(2) in irrigation solutions packaged in glass bottles was about half that at atmospheric levels; in solutions packaged in plastic, it was at atmospheric levels. As irrigation solutions were drained from the container, the pO(2) of the solution tended to rise toward atmospheric levels. The rate of pO(2) increase was markedly reduced by using a directly vented glass bottle. In the phacoemulsification procedures, bubble formation was most likely to occur with higher pO(2) and higher power settings. Observation of bubbles by the surgeon was highly correlated with endothelial damage. CONCLUSIONS: Keeping the pO(2) low reduced the risk of endothelial damage, especially at higher phacoemulsification powers. The packaging of irrigation solutions was the most important factor in controlling the initial pO(2) of the solution. The pO(2) can be minimized throughout a phacoemulsification procedure by using a directly vented glass bottle.

Actins↗