[Results of modified one-stage operation for cataract and glaucoma]

The paper analyzed the immediate and late results (the state of intraocular pressure and visual functions) of combined surgery for cataract and glaucoma, by using the developed instrument. Eighteen patients (19 eyes) aged 54 to 92 years who had open-angle glaucoma or phacotopic glaucoma (dislocation of the lens to the vitreous body) and cataract underwent combined surgery involving extraction of cataract, its phacoemulsification with intraocular lens (IOL) implantation through the scleral tunnel, and sinus trabeculectomy (STE) performed with a perforator, the instrument developed by the authors. The findings confirm the efficiency of the combined surgery (STE) with cataract extraction through variously extended scleral tunnels in patients with open-angle glaucoma, normalizing intraocular pressure and improving visual functions by one-stage surgery. Combined surgery for cataract extraction with IOL implantation through the scleral tunnel and STE, which is performed with the instrument proposed by the authors, has been put into practice.

Phacoemulsification using iris hooks and scleral fixation of the intraocular lens in patients with secondary glaucoma associated with lens subluxation

PURPOSE

We described the techniques and results of phacoemulsification using iris hook and scleral fixation of intraocular lens (IOL) in patients with secondary glaucoma associated with lens subluxation.

METHODS

Eight eyes of seven patients with secondary glaucoma associated with lens dislocation, who had undergone the surgery, were retrospectively reviewed.

RESULTS

At a mean of 23.5 months+/-13.6 (SD) after the surgery, the mean best-corrected visual acuity improved from 0.24+/-0.21 to 0.83+/-0.3, and mean intraocular pressure (IOP) was changed from 38.4+/-11.4 to 15.5+/-1.8 mmHg at the final examination. There were no vitreoretinal complications except cystoid macular oedema in one eye.

CONCLUSION

The technique appears to be safe and effective in terms of visual rehabilitation and controlling IOP in patients with secondary glaucoma associated with lens subluxation.

Efficacy of Cruise Control in controlling postocclusion surge with Legacy and Millennium venturi phacoemulsification machines

PURPOSE

To determine the efficacy of the Cruise Control surge-limiting device (Staar Surgical) with phacoemulsification machines known to have high levels of surge.

SETTING

John A. Moran Eye Center Clinical Laboratories.

METHODS

In an in vitro study, postocclusion anterior chamber depth changes were measured in fresh phakic human eye-bank eyes using the Alcon Legacy and Bausch & Lomb Millennium venturi machines in conjunction with the Staar Cruise Control device. Both machines were tested with 19-gauge non-Aspiration Bypass System tips at high-surge settings (500 mm Hg vacuum pressure, 75 cm bottle height, 40 mL/min flow rate for the Legacy) and low-surge settings (400 mm Hg vacuum pressure, 125 cm bottle height, 40 mL/min flow rate for the Legacy). Adjusted parameters of flow, vacuum, and irrigation were used based on previous studies to create identical conditions for each device tested. The effect of the Cruise Control device on aspiration rates was also tested with both machines at the low-surge settings.

RESULTS

At the high setting with the addition of Cruise Control, surge decreased significantly with the Legacy but was too large to measure with the Millennium venturi. At the low setting with the addition of Cruise Control, surge decreased significantly with both machines. Surge with the Millennium decreased from more than 1.0 mm to a mean of 0.21 mm +/- 0.02 (SD) (P<.0001). Surge with the Legacy decreased from a mean of 0.09 +/- 0.02 mm to 0.05 +/- 0 mm, a 42.9% decrease (P<.0001). The Millennium had the highest surge and aspiration rate before Cruise Control and the greatest percentage decrease in the surge and aspiration rates as a result of the addition of Cruise Control.

CONCLUSIONS

In the Legacy machine, the Cruise Control device had a statistically and clinically significant effect. Cruise Control had a large effect on fluidics as well as surge amplitude with the Millennium machine. The greater the flow or greater the initial surge, the greater the impact of the Cruise Control device.

Simulateur pédagogique médical : la phacoémulsification en réalité virtuelle

INTRODUCTION

Improvements in computer technology have made it possible to design a cataract surgery teaching simulator in real time.

MATERIAL AND METHODS

A computed representation of the lens was made with a mechanical model simulating the behavior of the lens, to which we added texture. The different models use mesh to make a section, which allowed us to make a section in real time using element removal or separation. Different models were used: a mass-spring mesh, a rigid model and a deformable model created using the finite element method. The contact with the lens is simulated by a collision sphere, which provides the interaction between the surgical instruments and the virtual environment. The surgical instruments viewed on the screen are controlled by a stylus with 6 degrees of freedom.

DISCUSSION

We obtained the first step of phacoemulsification in real time with a good visual aspect. The surgeon views the procedure and can modify his movements instantaneously. This simulator provides the opportunity for students to safely learn phacoemulsification and improve their technique with an infinite number of procedures.

CONCLUSION

The realism offered by this tool provides a rigorous teaching tool that might reduce the learning curve for phacoemulsification.

Development of an in vitro model to assess posterior capsule safety during phacoemulsification with ultrasound or AquaLase handpieces

PURPOSE

To develop a cadaver eye model that would assess posterior capsule (PC) vulnerability when different cataract removal technologies were evaluated and use the model to evaluate the relative amplitude levels required to rupture the human PC with the AquaLase handpiece (Alcon) compared with an ultrasound (US) handpiece.

SETTING

Private practice, Cincinnati, Ohio, USA.

METHODS

In part 1 of the study, 26 phakic human cadaver eyes were sectioned in the anteroposterior meridian. The anterior portion of the globe was placed cornea side down, and the vitreous was gently cleared from the posterior surface of the lens capsule. Ultrasound was applied directly to the central capsule after achieving a vacuum of 100 mm Hg. The power was incremented until rupture was observed. In part 2 of the study, the same procedure was repeated with 50 eye pairs. For each pair, US was randomly applied to 1 eye and AquaLase to the other. The 50 pairs were divided into 3 groups based on vacuum level: 100, 300, or 500 mm Hg.

RESULTS

Part 1 results show that at 100 mm Hg, the mean power needed to break the PC with US was 19% +/- 6% (SD). There was no correlation between time from harvest to test and rupture power (R(2) = 0.04) or between donor age and rupture power (R(2) = 0.2). When the same procedure was repeated in part 2, on average, US power ruptured the capsule at a lower power than the AquaLase magnitude at each vacuum setting. The respective means were 18.5% +/- 6.7% and 61.0% +/- 23.3% for 100 mm Hg, 15.2% +/- 5.4% and 47.1% +/- 14.5% for 300 mm Hg, and 11.8% +/- 6.5% and 20.0% +/- 9.4% for 500 mm Hg. The difference between the groups and the values within each group decreased as vacuum levels increased.

CONCLUSION

This new experimental model in a cadaver eye provides a useful method for comparing factors and techniques that contribute to PC rupture.

Preventing Posterior Capsular Opacification With an Endocapsular Equator Ring in a Young Human Eye

OBJECTIVE

To report the results of a specially designed closed ring with a square edge (endocapsular equator ring) in a young patient to prevent posterior capsular opacification.

METHODS

One eye of a 22-year-old atopic patient underwent endocapsular equator ring implantation with a 1-piece polymethylmethacrylate intraocular lens immediately after phacoemulsification at Hara Eye Hospital on January 10, 2003. The solid flexible silicone ring has an outer diameter of 9.0 mm, is 1.0 mm wide and 1.0 mm thick, and has a square edge. The loops of the intraocular lens are fixed in the inner groove of the ring. The contralateral control eye underwent phacoemulsification and implantation with a conventional intraocular lens implantation. The Hayashi method was used to determine the posterior capsular opacification score.

RESULTS

The ring retained the transparency of the entire posterior capsule. Two years postoperatively, the posterior capsular opacification score in the central area was 3.75 in the ring eye and 15.25 in the control eye, which underwent Nd:YAG laser capsulotomy 2.5 years postoperatively.

CONCLUSION

An endocapsular equator ring effectively prevents posterior capsular opacification in a young patient with atopic cataracts.

Objective measurement of postocclusion surge during phacoemulsification in human eye-bank eyes

PURPOSE

To objectively compare the postocclusion vacuum surge among different phacoemulsification machines and devices.

DESIGN

Experimental study.

METHODS

Infiniti, Legacy, Millennium, and Sovereign were tested in an eye-bank eye. All the machines were tested with 20-gauge non-ABS tips, 430 mm Hg vacuum pressure, 24 ml/minute aspiration rate, peristaltic pump, and 75 cm bottle height. In addition, Infiniti and Legacy were also tested with 20-gauge bypass tips (ABS), 125 cm bottle height, and 40 ml/minute flow rate. We also tested 19-gauge tips with Infiniti and Sovereign and the venturi pump for Millennium.

RESULTS

Significant differences were found between all the machines tested with Millennium peristaltic generating the least and Millennium Venturi the most surge. ABS tips significantly decreased the surge for Legacy but not for Infiniti. Cruise Control (CC) had a significant effect on Sovereign but not on Millennium. Increasing the bottle height decreased surge while increasing the flow increased surge for both Infiniti and Legacy. The 19-gauge tips increased surge for both Infiniti and Sovereign.

CONCLUSIONS

Surge varied over a range of 40 microm to more than 2 mm. ABS and CC decrease surge, especially when the machine is not functioning near the limits of surge prevention. Certain parameters, such as a 19-gauge tip and high flow, dramatically increased surge, whereas elevating the bottle ameliorates it. Understanding the impact of all these features will help in minimizing the problem.

The preventive effect of capsular tension ring in phacoemulsification of senile cataracts with pseudoexfoliation

We evaluated the preventive role of the capsular tension ring (CTR) in zonular and capsular complications in the phacoemulsification surgery of cataracts with pseudoexfoliation (PEX) in two groups of eyes with senile cataract associated with PEX, with (Group A) or without (Group B) CTR implantation. CTR implantation did not prove as effective as expected in preventing the zonulo-capsular complications. Contradictory to the significant increase of intracapsular intraocular lens (IOL) implantation rate, post-operative visual acuity did not improve in the same value.

Innovations in phacoemulsification technology

PURPOSE OF REVIEW

A working knowledge of the principles guiding recent technologic upgrades in phacoemulsification units will help the surgeon to maximize clinical benefits from the latest machines.

RECENT FINDINGS

Reduced thermal energy combined with more efficient emulsification resulting from microfractionation of ultrasound energy, and improved chamber stability from automatic fluidic adjustments are achievable with the recent technological advances.

SUMMARY

Improved safety and efficiency can be achieved with the most current advances in phacoemulsification technology.

Phacoemulsification using iris-hooks for capsular support in high myopic patient with subluxated lens and secondary angle closure glaucoma

We report an unusual case of angle closure glaucoma in a 78-year-old highly myopic female patient. The patient did not show any preoperative signs of subluxation of lens. However, the capsular bag was noted to be unstable during surgery. The patient was managed with phacoemulsification of lens using a novel method of iris hooks for stabilization of capsular bag during surgery.

[Influence of intraoperative pupil diameter and nuclear grade due to complications during Aqualase phacoemulsification]

PURPOSE

The aim of this study was to make an evaluation of the frequency of intraoperative complications during Aqualase phacoemulsification and correlate it to different intraoperative pupil diameters and nuclear grades.

METHODS

Aqualase phacoemulsification was performed in 23 eyes without retinal or optic disc pathology in 23 unselected patients (15 women and 8 men) who underwent out-patient cataract surgery. Nuclear grade, intraoperative pupil diameters and complications were recorded. The correlation of intraoperative complications with intraoperative pupil diameter and nuclear grade was determined using "Fisher's exact" test.

RESULTS

The average age of our patients was 70.3 (+/- 12.5) years, the mean best spectacle-corrected visual acuity (BSCVA) preoperatively was 0.39 (+/- 0.15) and the mean BSCVA postoperatively was 0.79 (+/- 0.13). The mean aqua time was 3.11 s (+/- 1.55 s) with maximum nuclear sclerosis of up to grade 3 (mean nuclear sclerosis 1.9). The aqua time correlated with the nuclear sclerosis (r = 0.90). The mean intraoperative pupil diameter was 7.2 (+/- 0.7) mm. In 2 of 3 patients with an intraoperative pupil diameter of 6 mm, iris touch occurred intraoperatively. There were no other intra- or postoperative complications. The frequency of iris touch was statistically significantly higher for reduced pupil diameters (p = 0.01). The nuclear grade with a maximum of 3 was without statistical significance to iris touch frequency (p > 0.05).

CONCLUSIONS

The number of iris traumas is significantly higher when the intraoperative pupil diameter is reduced. The iris should be protected in these cases. A prospective, randomised study should be performed to compare the number of intraoperative complications between ultrasound and Aqualase phacoemulsification.

Phaco fluidics and phaco ultrasound power modulations

The most common surgical procedure in the United States is cataract surgery; most specifically, phacoemulsification. Understanding the fluidics and ultrasonic power fundamentals for phacoemulsification is instrumental for their safe and efficient use. Although phaco machines allow a few decades ago, the basic concepts have remained the same. Phaco machines allow ultrasonic-assisted aspiration of the cataract while maintaining the stability within the eye and minimizing the trauma of surgery to ocular structures. In this light, the two primary concepts are the fluidics of the lens aspiration and the application of the ultrasound power.

Aspiration curette for anterior capsule polishing: Laboratory and clinical evaluation

Capsular fibrosis or fibrotic after-cataract results from transdifferation of anterior lens epithelial cells into myofibroblasts with consequent contraction and collagen deposition. To avoid possible complications, an instrument was designed for efficient and safe polishing of the anterior capsule leaf. The curette features an upward-facing slit with sharp-edged flanks and rounded turning points and an optional bypass hole. It is introduced through 3 equidistant 20-gauge paracentesis openings. In a laboratory test, vacuum rise time and vacuum levels under occlusion and the effect of adding a bypass hole were investigated for various pump settings. In a clinical pilot series, efficiency and safety of various designs were tested and vacuum and flow settings titrated for optimum performance; the clinical effect was determined in prospectively randomized bilateral studies. Optimum pump settings were 5 mL/min and 10 mm Hg with the nonventing curette and 7 to 10 mL/min and 50 mm Hg with the venting curette. A bypass hole delayed the vacuum rise and reduced the mean vacuum level on full occlusion. It also allowed fine-tuning the vacuum at the slit by varying the flow rate with the foot pedal. Anterior capsule polishing significantly decreased capsule fibrosis and is recommended when posterior capsulorhexis and optic buttonholing are combined.

Flexible iris retractors for management of zonular dialysis during planned phacoemulsification

BACKGROUND

The aim of this study was to determine the use of flexible iris retractors in four patients with zonular dialysis occurring during cataract surgery.

METHODS

We describe the use of flexible iris retractors to stretch and fixate the capsulorhexis over the zonular dehiscence sector for patients with traumatic zonular disruption occurring during phacoemulsification, which stabilizes the capsular bag and facilitates cataract extraction without complications.

RESULTS

Each of the four eyes was implanted with posterior chamber intraocular lens (PCIOL) successfully. The intraocular lenses (IOLs) remained well centered during the 12-month follow-up period and the patients enjoyed improved vision without complications.

CONCLUSION

Flexible iris retractor is a simple, convenient and useful instrument for managing zonular dehiscence that occurred during cataract extraction. It facilitates the removal of the residual lens material and IOL implantation without major complications.

Fluidics and heat generation of Alcon Infiniti and Legacy, Bausch & Lomb Millennium, and advanced medical optics sovereign phacoemulsification systems

PURPOSE

To study heat generation, vacuum, and flow characteristics of the Alcon Infiniti and Bausch & Lomb Millennium with results compared with the Alcon Legacy and advanced medical optics (AMO) Sovereign machines previously studied.

DESIGN

Experimental study.

METHODS

Heat generation with continuous ultrasound was determined with and without a 200-g weight. Flow and vacuum were determined from 12 to 40-ml/min in 2-ml/min steps. The impact of a STAAR Cruise Control was also tested.

RESULTS

Millennium created the most heat/20% of power (5.67 +/- 0.51 degrees C unweighted and 6.80 +/- 0.80 degrees C weighted), followed by Sovereign (4.59 +/- 0.70 degrees C unweighted and 5.65 +/- 0.72 degrees C weighted), Infiniti (2.79 +/- 0.62 degrees C unweighted and 3.96 +/- 0.31 degrees C weighted), and Legacy (1.99 +/- 0.49 degrees C unweighted and 4.27 +/- 0.76 degrees C weighted; P < .0001 for all comparisons between machines except Infiniti vs Legacy, both weighted). Flow studies revealed that Millennium Peristaltic was 17% less than indicated (P < .0001 to all other machines), and all other machines were within 3.5% of indicated. Cruise Control decreased flow by 4.1% (P < .0001 for same machine without it). Millennium Venturi had the greatest vacuum (81% more than the least Sovereign; P < .0001), and Cruise Control increased vacuum in a peristaltic machine 35% more than the Venturi system (P < .0001).

CONCLUSIONS

Percent power is not consistent in regard to heat generation, however, flow was accurate for all machines except Millennium Peristaltic. Restriction with Cruise Control elevates unoccluded vacuum to levels greater than the Venturi system tested.

[Incidence of posterior capsule opacification in patients submitted to phacoemulsification and expandable acrylic intraocular lens implantation]

PURPOSE

To evaluate prospectively the results of expandable acrylic intraocular lenses in patients submitted to phacoemulsification as regard posterior capsule opacification.

METHODS

The study group consisted of 830 patients, 1,200 eyes that underwent phacoemulsification from 1998 to 2002, by the same surgeon, using the same technique but with different diameters of capsulorrhexis, with expandable hydrophilic acrylic intraocular lens implantation. The mean follow-up was 2.4 years, ranging from 6 months to 4 years.

RESULTS

The total number of posterior capsule opacification was 54 cases.

CONCLUSIONS

The incidence of posterior capsule opacification was 4.6% in these patients.

[Performance evaluation of NeoSoniX technology in cataract surgery]

PURPOSE

The techniques and results of cataract surgery have improved dramatically with technological advancements. One of the reasons for this improvement would be the reduced use of ultrasound with the new phacoemulsification devices. The objective of this study is to confirm the theoretical advantage of the NeoSoniX handpiece.

METHODS

The authors compared the results of the parameters recorded by the Legacy phacoemulsification system during 300 cataract surgeries performed with the use of the conventional ultrasound handpiece and 100 performed with the innovative Neosonix. All surgeries were performed by the same senior surgeon, using the same surgical technique. The choice of handpiece was random. The handpieces were compared considering cataract grade of hardness, in relation to parameters of ultrasound time, amount of balanced saline solution, and percentage of average power used during surgery.

RESULTS

The analysis performed retrospectively on a chronological series of cases showed that the time of ultrasound used with the NeoSoniX handpiece was inferior to that with the conventional handpiece, for any cataract grade of hardness (p<0.000001). The volume of balanced saline solution used during surgical procedures was smaller, favoring the NeoSoniX technology (p<0.000001). In relation to the percentage of ultrasound energy used with the different technologies, an inferior value was found in the group who underwent surgery with the use of the NeoSoniX handpiece (p<0.000001).

CONCLUSIONS

Based on the information provided by these surgeries, we may claim that there was a significant superiority when using the NeoSoniX handpiece in comparison to the conventional Legacy machine handpiece in cataract surgeries, regardless of cataract grade.

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.