[Computer-assisted phacoemulsification for hard cataracts]

PURPOSE

to evaluate the efficiency of new torsional phacoemulsification software (Ozil IP system) in hard nucleus cataract extraction.

METHODS

45 eyes with hard senile cataract (degree III and IV) underwent phacoemulsification performed by the same surgeon, using the same technique (stop and chop). Infiniti (Alcon) platform was used, with Ozil IP software and Kelman phaco tip miniflared, 45 degrees. The nucleus was split into two and after that the first half was phacoemulsificated with IP-on (group 1) and the second half with IP-off (group 2). For every group we measured: cumulative dissipated energy (CDE), numbers of tip closure that needed manual desobstruction the amount of BSS used.

RESULTS

The mean CDE was the same in group 1 and in group 2 (between 6.2 and 14.9). The incidence of occlusion that needed manual desobstruction was lower in group 1 (5 times) than in group 2 (13 times). Group 2 used more BSS compared to group 1.

CONCLUSION

The new torsional software (IP system) significantly decreased occlusion time and balanced salt solution use over standard torsional software, particularly with denser cataracts.

Clinical application of 11-deoxycortisol in visualizing prolapsed vitreous body after posterior capsule rupture in cataract surgery

PURPOSE

To evaluate the clinical usefulness of 11-deoxycortisol, a precursor of cortisol in steroid metabolism, in visualizing the vitreous body in the anterior chamber after posterior capsule rupture during cataract surgery.

SETTING

Department of Ophthalmology, Tsukuba University Hospital, Ibaraki, Japan.

METHODS

Eight eyes had anterior vitrectomy during cataract surgery using this new technique. A suspension of 11-deoxycortisol was prepared by dilution in balanced salt solution without preservatives or emulsifying agents. After a posterior capsule rupture, the suspension was injected into the anterior chamber. The visual and anatomical outcomes of surgery were evaluated during a follow-up of 7 to 9 months.

RESULTS

After the 11-deoxycortisol injection, the vitreous body that had prolapsed through the torn posterior capsule, with white particles entrapped on its surface, became clearly visible. Complete removal of the prolapsed vitreous body was achieved easily and safely using an anterior vitrectomy system. No postoperative complications related to the use of 11-deoxycortisol were observed.

CONCLUSION

Injection of 11-deoxycortisol helped visualize the vitreous body in the anterior chamber after posterior capsule rupture. The technique minimized intraoperative and postoperative complications related to posterior capsule rupture and vitreous loss during cataract surgery [corrected]

Decrease in complications during cataract surgery with the use of a silicone-tipped irrigation/aspiration instrument

PURPOSE

To compare rates of vitreous loss during cataract surgery when a silicone-tipped irrigation/aspiration (I/A) instrument is used for cortex removal as opposed to a metal tip.

SETTING

Parkland Memorial Hospital, Dallas, Texas, USA.

METHODS

A retrospective chart review of all patients who had cataract extraction by phacoemulsification by third-year ophthalmology residents between September 2000 and February 2004 was conducted. A silicone-tipped I/A instrument was used to remove cortex for all surgeries beginning in September 2002, whereas a metal I/A tip was used previously.

RESULTS

Of the 1072 cases performed with a metal I/A tip, there were 13 cases of vitreous loss during cortex removal (rate 1.2%) and 26% of all vitreous loss during that time occurred during cortex removal. Of the 805 cases performed with a silicone I/A tip, there was a single case (0.1%) of vitreous loss during cortex removal (P=.004); only 4% of all vitreous loss during that time occurred during cortex removal (P=.011).

CONCLUSION

The overall incidence of vitreous loss during cortex removal and the ratio of vitreous loss during cortex removal to all cases of vitreous loss were significantly decreased using the silicone-tipped I/A instrument.

Outcome of dual infusion through irrigating chopper in conventional phacoemulsification

OBJECTIVE

To determine the operative advantage in terms of minimizing the complications following conventional phaco surgery with dual infusion through irrigating chopper.

METHODS

A Randomized Controlled Clinical Trial (RCCT) was conducted in the Ophthalmology Unit-III, Sindh Government Lyari General Hospital and DUHS and Al-Noor Eye Hospital Karachi, from March 2008 to February 2009. A total of 200 eyes with nuclear/cortico-nuclear cataract on Lens Opacity Classification System III underwent phacoemulsification. In all 100 eyes in group A were randomized to have conventional phacoemulsification with dual infusion technique through irrigating chopper and another 100 eyes in group B by conventional phaco surgery. Outcomes in two groups were judged by amount of Ringer's Lactate used, stability of anterior chamber and number of complications observed.

RESULTS

Rate of intra-operative complications was lower in group A as compared to group B (p=0.002). Anterior chamber depth was maintained in all cases of group A while it collapsed in 9 cases of group B which was highly significant (p=0.003). Mean amount of Ringer's Lactate used in group A was 260.2 +/- 55.07 ml and 195.8 +/- 35.0 ml in group B, which was significantly high (p<0.001).

CONCLUSION

Dual infusion through irrigating chopper serves triple function of irrigation, chopping and additional separate distant infusion. It improves anterior chamber stability and compensates surge and operative advantage to surgeon.

[Intelligent phaco--always necessary?]

PURPOSE

To assess the need of /P system use in soft cataract

METHODS

prospective study--40 eyes with soft cataract (+/++); surgery with Infinity system, Ozil handpiece; in 20 eyes we used low levels (max 70%) of torsional ultrasound power and IP system; in 20 eyes we used higher levels of torsional ultrasound power without IP system; we assessed: the CME value and the presence of cornela edema.

RESULTS

In cases with tosional ultrasound only: average value of CME--2.4; maxim value of CME--4.3; all corneas without edema. In cases with torsional ultrasound and IP system; average value of CME--3.6; maxim value of CME--7.2; 4 eyes with decemetic folds in central cornea.

CONCLUSIONS

In soft cataracts is better to not use IP system

Thermal comparison of Infiniti OZil and Signature Ellips phacoemulsification systems

PURPOSE

To determine thermal characteristics of Signature Ellips (Abbott Medical Optics) and Infiniti OZil (Alcon, Inc.) transverse ultrasound and compare both with longitudinal ultrasound in clinically relevant scenarios.

DESIGN

Laboratory investigation.

METHODS

Temperature increase over baseline after 60 seconds was measured in water at positions in 90-degree increments around the sleeve near the proximal needle shaft in an artificial chamber for Ellips and OZil on continuous ultrasound with aspiration blocked and unblocked. This was also done with Signature using longitudinal ultrasound, with and without micropulse (6 ms on, 12 ms off), with aspiration blocked and unblocked, and at the OZil sleeve tip on continuous transverse mode with aspiration unblocked.

RESULTS

OZil (8.1 +/- 0.3 C) had greater temperature increase than Ellips (5.2 +/- 0.3 C; P < .0001) with aspiration unblocked and blocked (29.3 +/- 1.0 C vs 12.2 +/- 0.7 C; P < .0001). OZil had uneven distribution of heat around the shaft (30.1 +/- 0.5 C vs 28.5 +/- 0.6 C; P < .0001), whereas Ellips did not (P = .57). OZil was cooler at the tip (6.6 +/- 0.2 C; P < .0001). Friction in a cadaver eye incision only increased these numbers by 10% (OZil, irrigation blocked).

CONCLUSIONS

Metal stress probably creates heat at the proximal needle junction for both transverse methods. Heat generation differences between OZil and Ellips result from the manner in which they create needle motion. Incision burns may occur, especially for OZil, under nonpulsed settings during fragment removal with occlusion when reaching across the anterior chamber such that the proximal needle shaft came near the wound.

[Influence AquaLase at corneal endothelial cells]

PURPOSE

To assess the effect of the cleaning of the posterior capsule using pulses of balanced salt solution (BSS) on the corneal endothelial cells.

METHODS

This pilot study involves 43 patients with bilateral cataracts having lens removal using torsional phacoemulsification (Ozil, Infiniti, Alcon) and bimanul irrigation/aspiration (I/A). Posterior capsule of the right eye of each patient was cleaned using pulses of BSS (AquaLase, Infiniti, Alcon). Surgery was performed by one of 2 surgeons (NJ, PR), both eyes of each patient was operated on by the same surgeon. Best corrected visual acuity (BCVA), endotelial cell count and pachymetry were evaluated pre- and postoperatively as well as occurence af peri- and postoperative complications.

RESULTS

Preoperative mean pachymetry (P) was 566 +/- 45 microm in the right eye (RE) and 562 +/- 42 microm in the left eye (LE), mean endotelial cell count (ECC) 2541 +/- 317 cells/mm2 (RE) and 2567 +/- 311 cells/mm2 (LE). Three months after surgery P was 557 +/- 43 microm (RE) and 558 +/- 45 microm (LE) and ECC 2368 +/- 416 cells/mm2 (RE) and 2396 +/- 417 cells/mm2 (LE). There was no statistical difference in postoperative changes of both corneal parameters between right and left eyes. Best corrected visual acuity improved in all eyes and no peri-or postoperative complications occured.

CONCLUSIONS

Cleaning of the posterior capsule using AquaLase is safe for corneal endothelial cells.

Comparison of actual vacuum pressures at the end of 3 phacoemulsification tips in swine eyes

PURPOSE

To compare the actual vacuum pressure at the end of an aspiration bypass system (ABS) phaco tip and a conventional tip in conditions similar to those during human cataract surgery.

SETTING

Kangbuk Samsung Hospital, Seoul, Korea.

METHODS

A 4.0 mm diameter rubber eraser ball was inserted in a phacoemulsified swine eye and engaged to a phaco tip. With a vacuum pressure of 300 mm Hg, the eraser ball was pulled in the opposite direction with the phaco tip. The pulling power separating the eraser ball from the phaco tip was measured using the volume of water dripped into a container connected to the eraser ball. Measurements were taken with an Infiniti ABS tip and 2 conventional tips: Sovereign (conventional tip S) and Infiniti (conventional tip I). Measurements were taken alternatively at random in the same eye.

RESULTS

The mean pulling power was 17.35 mL +/- 5.01 (SD) with conventional tip S and 16.85 +/- 4.45 mL with conventional tip I. The mean pulling power of the ABS tip was 13.35 +/- 4.32 mL, which was a mean 20.8% lower than that of conventional tip I (P = .016) and 23.1% lower than that of conventional tip S (P = .010).

CONCLUSIONS

The actual vacuum pressure of the phaco tip was significantly influenced by the presence of the ABS hole. To compensate for the decrease in actual vacuum pressure, surgeons should be aware of the characteristics of the ABS tip being used and change the standard settings accordingly.

[The first results of cataract phacoemulsification made by bimanual technique]

The results of 112 operations of bimanual ultrasound lens extraction through microincisions in cataracts of varying severity and origin are assessed in patients aged 46 to 85 years. The parameters of operation of ultrasound devices, the designs of accessory instruments (cataract hydrochoppers), and a nuclear scission procedure are considered. It is noted that this procedure is convenient in complicated cases: rigid iris and lens dislocation. The operations were observed to show a high efficiency: no postoperative astigmatism and rapid rehabilitation.

Cataract surgery (phacoemulsification) in difficult cases

By presenting three cataract surgeries, we discuss the difficulties of the interventions and the key moments. Case I: Mature cataract surgery on a patient with corneal opacities (maculas). Case II: Posterior polar cataract. Case III: Small pupil, shallow anterior chamber (dilating with Malyugin ring).

CONCLUSIONS

The surgery of a mature cataract on an eye with corneal opacities can be performed by a surgeon with enough experience. The final visual acuity depends on the clarity of the center of the cornea. During the operation of a posterior polar cataract we have to be prepared to the rupture of the posterior capsule, which is more frequent than in other cases. These interventions are better to be made in centers with posterior pole surgery capabilities. The Malyugin ring is a novel PMMA device, which dilates the pupil, creating decent conditions for a cataract surgery This device can be inserted and pulled out through a standard 2,8 mm incision.

Macular thickness and volume after uncomplicated phacoemulsification surgery evaluated by optical coherence tomography. A one-year follow-up

OBJECTIVE

To evaluate changes in the macular thickness and volume using optical coherence tomography in patients after phacoemulsification and intracapsular implantation of a foldable intraocular lens.

MATERIALS AND METHODS

The study included 82 patients (37 males and 45 females) after phacoemulsification and intracapsular implantaion of the same type of a foldable intraocular lens, without any other eye disease. Phacoemulsification was performed with an INFINITI machine. In all patients, macular thickness and volume were measured with an optical coherence tomograph (Stratus OCT) using the Fast Macular Thickness Map. The OCT evaluation was performed on days 1, 7, 30 and 90 postoperatively. In 58 patients (71%), it was additionally performed at 12 months after surgery and in 52 patients (63%) the macular parameters in the healthy and operated eyes were compared.

RESULTS

A statistically significant increase in the minimal retinal thickness was observed on days 30 (p<0.0005) and 90 (p<0.005) postoperatively compared to post-operative day 1. A statistically significant increase in the foveal volume was seen on days 30 (p<0.00005) and 90 (p<0.0005). A statistically significant increase in the volume of the entire macula was found on days 7, 30 and 90 (p<0.00005).

CONCLUSION

Uncomplicated cataract phacoemulsification is followed by increases in the central retinal thickness, foveal volume and volume of the entire macula on days 30 and 90 and at 12 months postoperatively. Further observation of patients is required to confirm whether the macular parameters will return to their values on day 1 postoperatively and if so, when this will occur.

Use of Malyugin pupil expansion device for intraoperative floppy-iris syndrome: results in 30 consecutive cases

PURPOSE

To evaluate a new disposable, small-pupil expansion device in tamsulosin patients with intraoperative floppy-iris syndrome (IFIS) having cataract surgery.

SETTING

Private practice, Los Altos, California, USA.

METHODS

The 5-0 polypropylene Malyugin pupil expansion device (MicroSurgical Technology) was used in 30 eyes from 21 tamsulosin patients having routine cataract surgery. The pupil diameter was measured at the beginning and end of surgery, and the severity of IFIS was graded. Intraoperative and postoperative complications were recorded.

RESULTS

The device maintained a constant 6.0 mm pupil diameter throughout surgery. Although iris prolapse was still possible, there were no significant intraoperative or postoperative complications despite the fact that 93% of the eyes had moderate to severe IFIS. All eyes achieved a best corrected visual acuity of at least 20/25. There was a tendency for ring deformation if flash sterilization was used without sufficient cooling time.

CONCLUSIONS

The disposable Malyugin pupil expansion device was highly effective at maintaining an adequate pupil opening in eyes with IFIS. It is easier and faster to use than iris retractors and other pupil expansion rings and represents an excellent small-pupil strategy.

A fluidics comparison of Alcon Infiniti, Bausch & Lomb Stellaris, and Advanced Medical Optics Signature phacoemulsification machines

PURPOSE

To compare three phacoemulsification machines for measurement accuracy and postocclusion surge (POS) in human cadaver eyes.

DESIGN

In vitro comparisons of machine accuracy and POS.

METHODS

Tip vacuum and flow were compared with machine indicated vacuum and flow. All machines were placed in two human cadaver eyes and POS was determined.

RESULTS

Vacuum (% of actual) was 101.9% +/- 1.7% for Infiniti (Alcon, Fort Worth, Texas, USA), 93.2% +/- 3.9% for Stellaris (Bausch & Lomb, Rochester, New York, USA), and 107.8% +/- 4.6% for Signature (Advanced Medical Optics, Santa, Ana, California, USA; P < .0001). At 60 ml/minute flow, actual flow and unoccluded flow vacuum (UFV) was 55.8 +/- 0.4 ml/minute and 197.7 +/- 0.7 mm Hg for Infiniti, 53.5 +/- 0.0 ml/minute and 179.8 +/- 0.9 mm Hg for Stellaris, and 58.5 +/- 0.0 ml/minute and 115.1 +/- 2.3 mm Hg for Signature (P < .0001). POS in an 32-year-old eye was 0.33 +/- 0.05 mm for Infiniti, 0.16 +/- 0.06 mm for Stellaris, and 0.13 +/- 0.04 mm for Signature at 550 mm Hg, 60 cm bottle height, 45 ml/minute flow with 19-gauge tips (P < .0001 for Infiniti vs Stellaris and Signature). POS in an 81-year-old eye was 1.51 +/- 0.22 mm for Infiniti, 0.83 +/- 0.06 mm for Stellaris, 0.67 +/- 0.01 mm for Signature at 400 mm Hg vacuum, 70 cm bottle height, 40 ml/minute flow with 19-gauge tips (P < .0001).

CONCLUSIONS

Machine-indicated accuracy, POS, and UFV were statistically significantly different. Signature had the lowest POS and vacuum to maintain flow. Regarding POS, Stellaris was close to Signature; regarding vacuum to maintain flow, Infiniti and Stellaris were similar. Minimizing POS and vacuum to maintain flow potentially are important in avoiding ocular damage and surgical complications.

The influence of viscoelastic substances on the corneal endothelium during cataract surgery by phacoemulsification

PURPOSE

To compare the ability of different ophthalmic viscoelastic devices to protect the corneal endothelium following in-the-bag phacoemulsification with posterior chamber intraocular lens (IOL) implantation.

MATERIAL & METHODS

We studied 50 patients with soft to moderately dense (Grade 1-3) cataract and corneal endothelial cell density of >2000 cells/mm2. The corneal response to surgery was evaluated by measuring the endothelial cell loss, the variation in the mean cell area of the endothelial cells (CV), and the central corneal thickness, all that by using a TOPCON SP 2000P noncontact, specular microscope. Data were recorded preoperatively and postoperatively.

RESULTS

Preoperatively no statistical significant difference was observed in cell count, CV or pachymetry among groups. Postoperatively, all the groups had a statistically significant decrease (p < 0.001) in endothelial cell count. There was an equal and significant (p < 0.001) increase in visual acuity. Between groups there was no statistically significant difference (p > 0.17) in any of the parameters we studied.

CONCLUSIONS

Between the OVDs we used, either DisCoVisc or ProVisc & VisCoat, there was no statistical significant difference neither in surgical outcome nor in endothelial layer aspect and function. DisCoVisc protected better the endothelium cells even if it was not statistically significant, and is the one that can be used for the entire surgical procedure.

Visual acuity in patients having foldable and non-foldable intra-ocular lens for cataract surgery

BACKGROUND

Intra-ocular lens (IOLs) is the most commonly use organ substitute worldwide. Question of different type of IOLs which would offer different post operative visual acuity (VA) has been asked.

OBJECTIVES

To compare the pre-operative and post operative visual acuity (VA) of cataract patients operated-patient and the use of non foldable and foldable IOLs in different age groups.

METHOD

Retrospective study of post operative VA of cataract patients-operated from Priest, Lerdsin Hospital in Bangkok and Lampang Hospital in northern part of Thailand. Methods to operate and type of IOLs implantation were recorded. The cases with pre-operative and intra-operative complications were excluded.

RESULTS

Post operative VA of cataract patients was better than pre-operation VA with statistically significant at p-value less than 0.05 and the results persisted for every age group. With phacoemulsification (PE) techniques, non-foldable IOLs offered better post operative VA than foldable IOLs in every age group except in age group of less than 40 and age group over 59 that showed statistically significant different at p-value less than 0.05.

CONCLUSION

Due to the nature of retrospective study, the cause of poor post operative VA was due to astigmatism which the pre-operative astigmatism were not recorded to fulfill complete analysis.

Modified capsular tension ring for cortical removal after implantation

We describe a modification of the original 14C Morcher capsular tension ring. The new ring, the Henderson capsule tension ring (HCTR, Morcher), is an open C-shaped loop made of poly(methyl methacrylate). It has 8 equally spaced indentations of 0.15 mm to improve the ease of removing nuclear and cortical material while maintaining equal expansion of the capsular bag. The HCTR is currently under review by the U.S. Food and Drug Administration.

Cataract surgery using the bimanual phacoemulsification technique with an Accurus system and Mackool microphaco tip

PURPOSE

To investigate the safety and effectiveness of the Accurus vitreoretinal and phacoemulsification system (Alcon, Inc.) for bimanual phacoemulsification surgery.

SETTING

Kosei Chuo Hospital, Tokyo, Japan.

METHODS

Phacoemulsification for age-related cataract was performed using a bimanual technique in 55 eyes and a coaxial technique in 31 eyes. The Accurus system with a venturi pump and a sleeveless ultrasonic tip or a Mackool microphaco tip was used in all cases. The 2 techniques were compared. In bimanual phacoemulsification, the 2 tips were evaluated to determine whether either reduced ocular tissue impairment.

RESULTS

The mean best corrected visual acuity 1 day after the surgery was 20/20 in both groups. There was no significant difference between the bimanual group and coaxial group except in ultrasound output (bimanual 22%, coaxial 28%; P = .01). Iris impairment was observed only in the bimanual group but was reduced by the use of the Mackool sleeved microphaco tip.

CONCLUSION

Bimanual phacoemulsification for cataract surgery using the Accurus system with a venturi pump and a Mackool microphaco tip was safe and effective and may provide a means of performing combined or successive cataract and vitreoretinal surgery.

Weight effect of saline accumulation in surgical drapes

BACKGROUND

Positive vitreal pressure during phacoemulsification is a known risk factor for posterior capsule rupture. Knowledge of modifiable causes of positive vitreal pressure is imperative to aid in its management intraoperatively. The aim of our study was to determine whether the weight from the accumulation of a large volume of saline in the surgical drapes could have an effect on intraocular pressure in patients. Such an effect could indicate a source of posterior vitreal pressure in patients undergoing prolonged phacoemulsification.

METHODS

In 23 adult patients undergoing phacoemulsification at the Jones Eye Institute at the University of Arkansas for Medical Sciences, intraocular pressure readings were taken before and after the addition of 500 cc of saline to the surgical drapes and taken again after removal of the saline.

RESULTS

Statistically significant differences in intraocular pressure were found between the baseline measurement, the measurement with saline, and the measurement after saline removal. No differences in the rise in intraocular pressure were found according to age, race, sex, or which eye was tested.

INTERPRETATION

Accumulation of a large volume of saline in surgical drapes has a modest effect on intraocular pressure. This may indicate a contributing cause of posterior vitreal pressure during prolonged phacoemulsification.

[Prospective randomized trial comparing Discovisc versus Healon in phacoemulsification]

OBJECTIVE

To compare the intraoperative behaviour of both, DisCoVisc and Healon used as viscoelastics in cataract surgery.

METHOD

We prospectively evaluated 35 patients with cataracts who underwent phacoemulsification and intraocular lens implantation. Patients were randomized into two groups. Group A included 17 patients in where Healon was used as a viscoelastic, whereas group B included 18 patients in where the viscoelastic used was DisCoVisc. After each procedure, the surgeon filled in a questionnaire describing the behaviour of the viscoelastic during the different stages of phacoemulsification.

RESULTS

DisCoVisc behaved as both cohesive and dispersive viscoelastic during capsulorrhexis, phacoemulsification and viscoelastic aspiration, whereas Healon acted as a cohesive substance during all surgical stages. DisCoVisc enabled better visualization and transparency during all the surgical stages and maintains the capsular bag better during the intraocular lens implantation. Viscoelastic aspiration was easier with Healon.

CONCLUSIONS

DisCoVisc is a new viscosurgical device with both cohesive and dispersive properties, which avoids using two different viscoelastics to improve the performance at different surgical stages. DisCoVisc has been shown to be more transparent and provides better anterior chamber maintenance when compared with Healon. Healon was more easily aspirated due to its cohesive character.