[Rotational technique for emulsification of soft lens nucleus]

Effective and atraumatic removal of a soft lens nucleus requires different surgical techniques compared to phacoemulsification of a dense nucleus.

PURPOSE

This study was conducted to develop a non-ultrasound technique for emulsification of a soft lens nucleus.

MATERIAL AND METHODS

Fifty-seven patients (57 eyes) underwent surgery. In 23 cases, early or immature cataracts were detected, and in 34 cases, lens removal was performed for refractive purposes in high myopia and complex myopic astigmatism. Phacoemulsifier Centurion Vision System (Alcon Laboratories, Inc., USA) was used for the surgery. Aspiration of soft lens nucleus was done using a rotational technique. The following aspects were evaluated in the course of the surgery: the volume of the required irrigation solution, and the frequency needing to involve ultrasound for complete emulsification of the lens nucleus. Intraoperative and postoperative complications were also assessed.

RESULTS

The surgery was uneventful in all cases. There were no violations of the integrity of capsulorhexis edge. The need for short pulses of minimal power ultrasound during the removal of the soft lens using this technique arose only in 11 (19.3%) cases. The effective ultrasound time was less than 1 second. The required volume of irrigation solution was 33.0 (24.0; 43.0) ml, which does not differ significantly from that in ultrasonic phacoemulsification.

CONCLUSIONS

The use of modern phacoemulsifiers providing a high vacuum level allows successful removal of a soft lens without using ultrasound, which prevents its negative impact on the ocular tissues. The use of adequate surgical techniques, including the optimal direction of rotation of the lens nucleus in the rotational technique, improves the efficiency of soft lens nucleus removal.

[Surgical technique for aspiration of soft lens nucleus with preoperative femtosecond laser-assisted fragmentation]

Fragmentation and aspiration of soft cataracts require different surgical techniques and approaches compared to the removal of dense nuclei, including when using a femtosecond laser.

PURPOSE

This study was conducted to develop a non-ultrasound technique for aspiration of a soft lens nucleus after its preliminary femtosecond laser-assisted fragmentation.

MATERIAL AND METHODS

The study included 63 patients (63 eyes) aged 23 to 40 years who underwent surgery. In 27 cases, early or immature cataract was observed, and in 36 cases, cataract removal was performed for refractive purposes in high myopia and complex myopic astigmatism. The VICTUS femtosecond laser surgical system (Technolas Perfect Vision GmbH, Germany) was used for preliminary fragmentation of the lens nucleus. Surgeries were performed using the Centurion Vision System phacoemulsifier (Alcon Laboratories, Inc., USA). The volume of the required irrigation solution was evaluated during the surgery. Intraoperative and postoperative complications were assessed.

RESULTS

The surgery was performed without complications in all cases. Capsulorhexis edge was completely preserved along its entire circumference. The study showed the fundamental possibility of aspirating a cataract with a nucleus of grade I-II density without low-frequency ultrasound after preliminary femtosecond laser-assisted fragmentation of the nucleus with a "grid" pattern, which ensures minimal fragment size in the central zone of the nucleus. The volume of irrigation solution required for aspiration of the nucleus was 36.0 (27.0; 44.0) ml, which does not significantly differ from the volume of solution during ultrasound phacoemulsification of a nucleus of such density.

CONCLUSIONS

Femtosecond laser-assisted fragmentation of the lens nucleus with a "grid" pattern and phacoemulsifier systems with a high vacuum level allow effective aspiration of a soft lens without using low-frequency ultrasound.

[Influence of the pattern of femtosecond laser-assisted lens nucleus fragmentation on the energy and hydrodynamic parameters of phacoemulsification]

The influence of various patterns of preliminary femtosecond laser-assisted fragmentation of the lens nucleus on the energy and hydrodynamic parameters of phacoemulsification remains insufficiently studied.

PURPOSE

This study evaluates the influence of various patterns of preliminary femtosecond laser-assisted fragmentation of the lens nucleus on the energy, hydrodynamic parameters of phacoemulsification, and the degree of corneal endothelial cell loss.

MATERIAL AND METHODS

Hybrid phacoemulsification was performed in 336 patients (336 eyes) with grade IV immature cataract according to the Buratto classification in three age-matched groups. Group 1 included 103 patients (103 eyes) who underwent hybrid phacoemulsification with preliminary femtosecond laser-assisted fragmentation of the nucleus with a «pizza» pattern (division of the nucleus with 10 radial cuts). Group 2 included 112 patients (112 eyes) who underwent femtosecond laser-assisted fragmentation of the nucleus with a «cylinders» pattern (division of the nucleus with 8 radial cuts in combination with 5 circular cuts). Group 3 included 121 patients (121 eyes) who underwent femtosecond laser-assisted fragmentation of the nucleus with a «grid» pattern (division of the nucleus with 8 radial cuts in combination with multiple mutually perpendicular cuts in the central zone in the form of a grid with a 0.5 mm cell). Effective ultrasound time and the volume of irrigation solution for emulsification of the lens nucleus fragments were determined during the operation. The loss of corneal endothelial cells was assessed 3 months after surgery.

RESULTS

The minimum effective ultrasound time was noted after using the "grid" pattern - 4.05 (2.88; 4.74) s, which was significantly less than with the "cylinders" pattern - 4.97 (3.78; 5.88) s and the "pizza" pattern - 6.15 (4.52; 7.75) s (p<0.05). The effective ultrasound time when using the "cylinders" pattern was significantly less than with the "pizza" pattern (p<0.05). The volume of irrigation solution used for emulsification of the lens nucleus fragments was significantly less in the "grid" pattern - 41.5 (33.5; 49.5) ml compared to the "cylinders" patterns 58.5 (51.0; 66.0), p<0.05 and "pizza" pattern 75.0 (66.0; 83.5), p<0.01. The volume of irrigation solution when using the "cylinders" pattern was significantly less than when using the "pizza" pattern (p<0.05). The loss of corneal endothelial cells after using the "grid" pattern was 8.82 (7.59; 9.87)%, which was significantly less than after the "cylinders" patterns - 9.97 (8.81; 10.83)%, p<0.05 and "pizza" - 11.70 (10.62; 12.97)%, p<0.05. At the same time, the loss of endothelial cells after using the "cylinders" pattern was significantly less than after the "pizza" pattern (p<0.05).

CONCLUSIONS

The choice of the optimal pattern of preliminary femtosecond laser-assisted fragmentation of the lens nucleus provides a significant decrease in the energy and hydrodynamic parameters of phacoemulsification and, accordingly, the loss of corneal endothelial cells.

[Optimization of phacoemulsification technique for Morgagnian cataract]

PURPOSE

This study was conducted to develop a new optimized phacoemulsification technique for Morgagnian cataract taking into account the anatomical and topographic parameters of the lens nucleus.

MATERIAL AND METHODS

A working classification of Morgagnian cataract was developed based on the size of the nucleus: if the edge of the nucleus is visualized at the upper edge of the pupil or between the upper edge and the middle of the pupil, it was classified as an initial stage of Morgagnian cataract with a large nucleus; if the upper edge of the nucleus is visualized in the middle of the pupil and below, it was classified as an advanced stage of Morgagnian cataract with a small nucleus. The first group included six patients who underwent surgery using the scaffold technique with removal of the whole small nucleus into the anterior chamber. The second group included 11 patients who underwent surgery using the scaffold technique with removal of the last fragment of the nucleus into the anterior chamber.

RESULTS

The use of the scaffold technique with removal of the nucleus into the anterior chamber helped reduce the number of intraoperative complications to 16.7% in the first group, compared to 27.3% in the second group, and the percentage of endothelial cell loss to 10.1% in the first group, compared to 10.7% in the second group.

CONCLUSIONS

The anatomical and topographic features of the lens and the anterior segment of the eye in Morgagnian cataract with a small nucleus allow for preliminary implantation of an intraocular lens into the capsular bag to protect the posterior capsule during phacoemulsification of the nucleus with minimal mechanical, hydrodynamic and acoustic damage to the surrounding structures of the eye.

Phacoemulsification in the Vitreous Cavity for Retained Nuclear Lens Fragments

Purpose

To evaluate anatomic and functional results after surgery of retained lens fragments in the vitreous cavity after previous phacoemulsification.

Methods

The authors studied retrospectively 18 patients who underwent pars plana vitrectomy (PPV) for retained nuclear lens fragments. Patients having only cortical material in the vitreous cavity were excluded. In all cases the nucleus or nuclear fragments were removed after a complete vitrectomy using perfluorocarbon injection in the vitreous cavity, associated with phacoemulsification in the vitreous cavity. The authors used a conventional phaco probe devoid of the silicone sleeve. Time lapse between cataract surgery and vitrectomy varied between 0 and 24 days (mean 8.2 ± 7.4). Follow-up was 33.9 ± 20.6 months (range 4 to 53).

Results

The mean final best-corrected visual acuity (BCVA) was 20/45 (range 20/400 to 20/20). It was 20/40 or better in 33% of patients, reaching 40% when patients with pevious macular disease were excluded. A total of 61% of patients reached a final BCVA ranging from 20/50 to 20/200. Retinal detachment occurred in one eye and topical medications were necessary to manage intraocular pressure in four cases.

Conclusions

PPV with intravitreous phacoemulsification is the technique of choice for dislocated nuclei or nuclear fragments in the vitreous cavity.

[Comparison study of new nucleus fragmentation technique in dense cataract phacoemulsification]

Comparison study of new fragmentation technique of dense nucleus in ultrasound phacoemulsification is performed. Proposed method of dense nucleus fragmentation allows to decrease equivalent time of ultrasound exposure using Ozil and NeoSoniX techniques. Minimal loss of corneal posterior epithelial cells was showed in combination of developed nucleus fragmentation technique with torsional phacoemulsification (Ozil). Combination of new fragmentation technique of dense nucleus (IV stage) with Ozil technique results in significant decrease of surgical trauma and time of rehabilitation.

Trench, lollipop, lift and chop technique for mild to moderate cataracts

No abstract available.DOI: http://dx.doi.org/10.3126/nepjoph.v4i2.6561 Nepal J Ophthalmol 2012; 4 (2): 344-345  

Capsulotomy and hydroprocedures for nucleus prolapse in manual small incision cataract surgery

Manual small incision cataract surgery (MSICS) involves the manual removal of nucleus through a scleral tunnel. To achieve 100% success every time, one has to do a good capsulotomy and should master the technique to prolapse the nucleus into anterior chamber. During conversion from extracapsular cataract surgery to MSICS, one can perform a can-opener capsulotomy and prolapse the nucleus. However, it is safer and better to perform a capsulorrhexis and hydroprolapse the nucleus, as it makes the rest of the steps of MSICS comfortable. Use of trypan blue in white and brown cataracts makes the capsulorrhexis and prolapse simple and safe. Extra caution should be taken in cases with hypermature cataracts with weak zonules and subluxated cataracts.

Torsional ultrasound modality for hard nucleus phacoemulsification cataract extraction

AIM

To evaluate the efficacy and safety of phacoemulsification using torsional modality with different parameter settings for hard nucleus cataract extraction.

DESIGN

A prospective, randomised clinical study.

METHODS

A clinical practice study conducted at the Cataract Service, Zhongshan Ophthalmic Center, Sun-Yat-Sen University, and Guangzhou. One eye each from 198 consecutive patients with cataract density grade IV according to the Emery-Little system classification system, requiring phacoemulsification and intraocular lens implantation, was included. Eyes were randomly assigned to the Linear Torsional combined with Ultrasound power group (Linear Tor+US group, n = 66), 100% Fixed Torsional group (Fixed Tor group, n = 65) and conventional Ultrasound burst group (US group, n = 67). All surgeries were performed by a single experienced surgeon and outcomes evaluated by another surgeon masked to treatment. Intraoperative parameters were Ultrasound Time (UST), Cumulative Dissipated Energy (CDE) and surgical complications. Patients were examined on post-op days 1, 7 and 30. Postoperative outcomes were final best corrected visual acuity (BCVA), average central and incisional corneal thickness and central endothelial cell counts.

RESULTS

The mean UST was lower in the Fixed Tor group than in the US group and in the Lin US+Tor group (p0.01), greater average central corneal and incisional thickness on days 1, 7 (p0.01), and higher average corneal endothelial cell losses on day 7 and 30 days (p

CONCLUSIONS

Torsional combined with ultrasound power or high fixed torsional amplitude can yield more effective hard nucleus phacoemulsification than conventional ultrasound modality.

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Key Words Collapse

MESH Headings

• Aged
• Aged, 80 and over
• Cornea/pathology
• Endothelium, Corneal/pathology
• Female
• Humans
• Lens Nucleus, Crystalline/surgery
• Male
• Middle Aged
• Phacoemulsification/methods
• Prospective Studies
• Tomography, Optical Coherence
• Treatment Outcome
• Ultrasonic Therapy/methods
• Visual Acuity

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Grants Collapse

Affiliation(s)

M Zeng Zhongshan Ophthalmic Center, Sun-Yat-Sen University Guangzhou, People’s Republic of China The Second Affiliated Hospital of Guangzhou Medical College, Guangzhou, People’s Republic of China
X Liu Zhongshan Ophthalmic Center, Sun-Yat-Sen University Guangzhou, People’s Republic of China
Y Liu Zhongshan Ophthalmic Center, Sun-Yat-Sen University Guangzhou, People’s Republic of China
Y Xia Zhongshan Ophthalmic Center, Sun-Yat-Sen University Guangzhou, People’s Republic of China
L Luo Zhongshan Ophthalmic Center, Sun-Yat-Sen University Guangzhou, People’s Republic of China
Z Yuan Zhongshan Ophthalmic Center, Sun-Yat-Sen University Guangzhou, People’s Republic of China
Y Zeng Zhongshan Ophthalmic Center, Sun-Yat-Sen University Guangzhou, People’s Republic of China
Y Liu Zhongshan Ophthalmic Center, Sun-Yat-Sen University Guangzhou, People’s Republic of China

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Management of the hard posterior polar cataract

I describe a technique for managing the posterior polar cataract with a dense nucleus by initially sculpting a central trough to the depth of the polar opacity. The nucleus is partially cracked in the periphery, avoiding the polar opacity, and then chopped into quadrants without rotating. Next, the phaco tip engages the core of the nuclear quadrant while a cleavage plane is manually dissected along the lenticular lamellae using a Nagahara phaco chopper, with the tip rotated slightly so it points somewhat toward the equator of the lens, to a depth estimated to leave a nuclear shell, sparing the polar cataract. The nucleus is peeled away from the outer nucleus shell, which is kept in place by the phaco chopper. The intact nuclear plate is removed last and any capsular defect managed accordingly. This technique minimizes the risk for losing a nuclear fragment into the vitreous cavity.

Retained Nuclear Fragments in the Anterior Chamber after Phacoemulsification with an Intact Posterior Capsule

OBJECTIVE

To review the clinical features and treatment of patients with retained nuclear fragments in the anterior chamber (AC).

DESIGN

Single-center, retrospective, noncomparative, consecutive case series.

PARTICIPANTS

Sixteen patients with a diagnosis of retained nuclear fragments in the AC.

METHODS

Retrospective review of the medical records at Bascom Palmer Eye Institute in Miami, Florida, to identify all patients with a diagnosis of retained nuclear fragments in the AC after phacoemulsification surgery without rupture of the posterior capsule. Charts were reviewed and patient characteristics, ocular history, clinical findings, treatment (medical and surgical), and visual outcomes were recorded.

MAIN OUTCOME MEASURES

Visual outcome and visual acuity at last follow-up visit.

RESULTS

Most patients presented with corneal edema and anterior segment inflammation. All patients proved refractory to medical management, and surgical extraction of the retained lens fragment was required. Ten patients were myopic or had long axial lengths and/or steep keratometry readings. Three patients underwent penetrating keratoplasty for intractable corneal edema. One patient required a second surgery for fragment removal after a previous unsuccessful attempt at removal. Visual outcomes for the patients without macular disease who had lens fragment removal alone ranged from 20/20 to 20/40. Of the 2 patients without macular disease who underwent penetrating keratoplasty, the visual outcomes were 20/50 and 20/30.

CONCLUSIONS

Retention of nuclear fragments in the AC may occur after phacoemulsification. This complication was associated with myopia in a majority of patients in this series, and we hypothesize that small fragments may hide in the posterior chamber in these larger eyes. Surgical removal was associated with a good visual outcome in patients without macular disease.

Aqualase for cataract extraction

PURPOSE

To report our experience of using Aqualase technology for cataract extraction.

METHODS

In total, 33 patients (20 females; mean age 71.4 years) underwent cataract surgery using Aqualase through a 3.2-mm corneal incision. Grade of nucleus, nuclear removal technique, and intraoperative complications were noted. Clinical parameters from postoperative visits were collected.

RESULTS

Aqualase is capable of removing cataracts up to nuclear sclerosis 2+ (out of 4) with relative ease. Nuclei graded 2+ or greater were technically more difficult and conversion to ultrasound phacoemulsification was required in one case. Two posterior capsule ruptures occurred: one during nucleus removal (contact with the tip while aspirating without Aqualase) and one unrelated to Aqualase during aspiration of cortex. Of 25 patients seen on the first postoperative day, 22 had a clear cornea. A total of 96% patients without preoperative comorbidity achieved 6/9 or better postoperatively. One patient had transient postoperative uveitis.

CONCLUSIONS

Removal of softer cataracts with Aqualase has the theoretical advantage over phacoemulsification, by carrying less risk to the posterior capsule, since the handpiece has a smooth polymer tip that has no mechanical motion inside the eye. However, the tip should not be considered entirely capsule-friendly, as rupture is possible with the foot-pedal in position two (aspiration only). Although certain adjustments to the technique are required, the method is similar enough to phacoemulsification to ensure a brief learning curve. With increasingly firm cataracts, Aqualase becomes less effective and ultrasound phacoemulsification is still superior for such cases, in our experience.

Illuminated endochopper in the management of posteriorly dislocated lens nucleus

We describe the use of an illuminated endochopper (a prototype instrument produced by DORC International) in the management of a posteriorly dislocated lens nucleus or lens particles. This instrument helps to divide the lens nucleus or its fragments into small pieces and thus reduces time and ultrasound energy.

[20 rules for hard nucleus phacoemulsification]

The mature cataract with hard nucleus still represents one of the most difficult task for modern phacoemulsification. The author presents some practical advise concerning both less experienced and experienced surgeons.

Chopstick technique for nucleus removal in an impending dropped nucleus

We describe a bimanual chopstick technique for nucleus removal after a posterior capsule tear and an impending dropped nucleus during phacoemulsification. The technique stabilizes the nucleus and nuclear fragments by providing posterior support with a Sinskey hook introduced from the pars plana. Once supported, the nucleus is gripped between 2 instruments, brought out of the capsular bag into the anterior chamber, and then taken out of the enlarged wound. This bimanual removal technique causes minimal disturbance to the vitreous, iris, and cornea.

Inside-out delineation

A technique of achieving precise hydrodelineation, in which fluid is injected from the inside of the nucleus to the outside, is described. The desired thickness of the nucleus-epinucleus bowl can be accomplished because the right-angled cannula can direct the fluid in the desired plane. This technique is useful in eyes with posterior polar cataracts and in eyes with dense cataracts in which aggressive phacoparameters are necessary for their removal.

Comparison of Nagahara phaco-chop and stop-and-chop phacoemulsification nucleotomy techniques

PURPOSE

To compare intraoperative and postoperative effects of Nagahara phaco-chop and stop-and-chop phacoemulsification nucleotomy techniques.

SETTING

Department of Ophthalmology, SBMU First Aid and Traumatology Hospital, Ankara, Turkey.

METHODS

Seventy patients were evaluated prospectively in 2 groups. The Nagahara phaco-chop nucleotomy technique was performed in Group 1 (35 eyes) and the stop-and-chop technique in Group 2 (35 eyes). There were no significant between-group differences. The mean phaco time, phaco power, effective phaco time, time to achieve maximum vision, corneal thickness increase relative to the preoperative values, and time to return to the preoperative values were determined. All parameters in both groups were statistically compared using the chi-square test and the independent-samples t test.

RESULTS

The mean phaco time was 1.3 minutes +/- 0.7 (SD), phaco power was 16.7% +/- 5.0%, and effective phaco time was 14.9 +/- 11.8 seconds in Group 1 and 1.8 +/- 0.9 minutes, 20.0% +/- 6.2%, and 22.3 +/- 14.2 seconds, respectively, in Group 2. The mean time to achieve maximum vision postoperatively was 6.9 +/- 3.7 days in Group 1 and 11.7 +/- 7.7 days in Group 2. The mean postoperative corneal thickness increase in Group 1 and Group 2 was 52.3 +/- 84.5 microm and 111.6 +/- 151.2 microm, respectively, and the mean time to return to preoperative pachymetry values, 9.8 +/- 5.7 days and 13.7 +/- 10.0 days, respectively. There were significant between-group differences in these parameters.

CONCLUSIONS

The Nagahara phaco-chop technique had fewer negative effects on the corneal endothelium as less ultrasonic energy was used. This accelerated the functional healing process and the return to preoperative physiologic values.

[A new method of macrofragmentation of dense nuclei by using loop fragmentizer]

The study results showed a principle possibility to fragmentize the most dense lens nuclei by means of a nylon cutting loop. The safety and efficiency of applying a loop fragmentizer in phacoemulsification of high-density cataract were equally demonstrated. The method advantages are conditioned by that a preliminary splitting of the nucleus into fragments without trenches being shaped cuts essentially the total capacity and duration of ultrasound impact, thus, the irrigation time and the needed volume of balance salt solution also decrease intraoperatively: it, naturally, diminishes the generally-known traumatic aftermaths of surgical intervention.

Pop-and-chop nucleofractis

Horizontal chopping is effective for endocapsular nucleofractis. We describe pop and chop, a variant of chopping that enables an easy first crack and initial segment removal. It involves partial extracapsular prolapse of the nucleus prior to the initial chop. It is particularly useful when hydrodissection results in partial prolapse of the lens nucleus so that it is wedged into the anterior capsule opening. It is also helpful when beginning surgeons are learning phaco chop.

Posterior assisted levitation for nucleus retrieval using Viscoat after posterior capsule rupture

A pars plana injection of Viscoat (sodium hyaluronate 3%-chondroitin sulfate 4%) was used to stabilize and elevate a descending nucleus in 8 patients with posterior capsule rupture. The nucleus or nuclear remnants were successfully removed in all 8 patients.

Timing of dislocated nuclear fragment management after cataract surgery

PURPOSE

To determine the timing of vitrectomy in patients with dislocated nuclear fragments after phacoemulsification and to correlate timing with visual outcomes.

SETTING

University Eye Clinic of Ioannina, Ioannina, Greece.

METHODS

This was a retrospective review of the records of 26 patients who had phacoemulsification at the University Eye Clinic of Ioannina over a 5-year period. The mean age of the 13 men and 13 women was 66.9 years (range 59 to 80 years). All patients had nucleus or nuclear fragment dislocation into the vitreous cavity during phacoemulsification and had vitrectomy and removal of the dislocated nucleus. The postoperative follow-up ranged from 3 to 9 months.

RESULTS

Eight patients (30.8%) had vitrectomy at the time of phacoemulsification (Group A), 8 (30.8%) within 3 weeks (Group B), and 10 (38.5%) after more than 3 weeks (Group C). Patients in Group A did not develop complications, and 87.5% achieved a final visual acuity of 5/10 or better. In Group B, 4 patients (50%) developed moderate intraocular inflammation and 5 patients achieved a final visual acuity of 5/10 or better. Six patients in Group C (60%) had phacoanaphylactic glaucoma and 3 (30.0%), retinal detachment; 70.0% had a final visual acuity of 3/10 or worse.

CONCLUSION

Early vitrectomy (fewer than 3 weeks postoperatively) was associated with better visual results, while late vitrectomy resulted in limited visual acuity in a high percentage of patients and increased the risk for glaucoma and retinal detachment.

Phacoemulsification using the burst mode

PURPOSE

To compare the amount of ultrasound (US) energy required for burst mode and pulse mode during nuclear fragment emulsification.

SETTING

Instituto de la Visión, University of Buenos Aires, Buenos Aires, Argentina.

METHODS

The ultrasound time (UST) and effective US power (USP) used by 2 surgeons were retrospectively compared. Nuclear fragments were emulsified using the pulse mode in 82 cases (Group 1) and the burst mode in 118 cases (Group 2). The 2 groups were divided according to nuclear hardness: 0 to 2+ (subgroups 1a and 2a) or 3+ to 4+ (subgroups 1b and 2b). The difference in nuclear hardness between Groups 1 and 2 was not statistically significant.

RESULTS

The mean UST and USP were, respectively, 1.64 minutes +/- 0.98 (SD) at 10.53% +/- 4.46% in subgroup 1a and 0.56 +/- 0.46 minutes at 10.51% +/- 5.80% in subgroup 1b. The respective means were 2.94 +/- 1.36 minutes at 15.14% +/- 4.49% in subgroup 2a and 0.75 +/- 0.52 minutes at 10.04% +/- 3.12% in subgroup 2b. The differences between subgroups were statistically significant except between subgroups 2a and 2b.

CONCLUSION

The burst mode increased US efficiency, especially when used for hard cataracts.

Step-down technique

From the beginning of nuclear fragment removal to the end, we progressively reduce all the parameters, ie, energy, vacuum, and aspiration flow rate, in a step-by-step manner proportionate to the posterior capsule exposure. This promotes adaptation of various parameters to the appropriate stages of surgery and allows the trainee and expert surgeon to perform posterior plane phacoemulsification. We recommend this technique for emulsification of dense as well as optimum-grade cataracts.

Nucleus cryoinversion for extraction of highly complicated cataracts

We describe a technique for cataract extraction in vitrectomized eyes that uses secured removal of the nucleus with no manipulation of the capsular bag. After a large scleral tunnel is prepared and a capsulorhexis created, a 20-gauge retinal cryoprobe enveloped in a plastic or a silicone sleeve is introduced into the anterior chamber. The cryoprobe engages the nucleus by a "freeze-grip" and rotates it 180 degrees so that the nucleus is elevated into the anterior chamber with no force applied to the capsule and the cryoprobe supporting it from below. The cryoprobe is replaced by a vectis under the nucleus and with the help of another instrument from above, the nucleus is removed. Aspiration of cortical material under low-pressure fluid maintenance of the anterior chamber completes removal of the cataract. An intraocular lens is then implanted in the ciliary sulcus for maximum capsule support.

Effect of hydrodissection on intraoperative performance: randomized study

PURPOSE

To evaluate the effect of hydrodissection on intraoperative performance during phacoemulsification of age-related nuclear cataracts.

SETTING

Iladevi Cataract & IOL Research Centre, Ahmedabad, India, and Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.

METHODS

In a prospective study, 86 eyes were randomly assigned to have multiquadrant hydrodissection (+HD, n = 48) or no hydrodissection (-HD, n = 38) during phacoemulsification of a grade 1 to 3 nuclear cataract. Excluded were patients with grade 4 or 5 nuclear sclerosis, a poorly dilating pupil, or associated ocular/systemic disease. Parameters assessed were nucleus and cortex removal time, the amount of fluid used for cortex removal, and the total amount of fluid used. The ease of nucleus rotation and cortical cleanup was also evaluated and graded subjectively as very easy, difficult, or very difficult. Data were analyzed using the Student t test and the chi-square test.

RESULTS

The mean nucleus removal time was 355 seconds +/- 237 (SD) and 474 +/- 212 seconds in the +HD and -HD groups, respectively (P =.09). The mean cortex removal time was significantly less in the +HD group than in the -HD group (79 +/- 51 seconds and 220 +/- 222 seconds, respectively) (P =.007). Significantly less fluid (43%) was used for cortex removal in the +HD group than in the -HD group (mean 70 +/- 45 mL and 123 +/- 82 mL, respectively) (P =.013), and significantly less total fluid (35%) was used in the +HD group (312 +/- 132 mL and 422 +/- 80 mL, respectively) (P =.002). Nucleus rotation was easy in all eyes in the +HD group; 68.43% of eyes in the -HD group failed to achieve rotation (P =.001). Cortex removal was very easy in 52.08% of eyes in the +HD group and easy in 47.90%; it was easy in 52.63% in the -HD group, difficult in 36.84%, and very difficult in 10.52%.

CONCLUSION

The use of multiquadrant cortical-cleaving hydrodissection made removal of the lens nucleus and cortex easier and faster during phacoemulsification of age-related nuclear cataracts.

Phaco one-chop nucleotomy

Phaco one-chop, a hybrid of the phaco-chop, stop-and-chop, and phaco-flip techniques, has 3 main phaco phases: embedding the phaco tip and chopping, flipping the right heminucleus without nucleus rotation, and evacuating the remaining left heminucleus in the bag. Of 198 eyes evaluated, 86% had a Lens Opacities Classification System III cataract grade of 3 to 6. The mean equivalent phaco time (EPT) was 1.9 seconds; for the densest cataracts, the highest phaco power needed was 5.3%. The mean overall power was 2.1%. Thus, the phaco one-chop method requires less EPT and phaco power and allows greater surgeon control for efficiency and predictability than the techniques from which it was derived.

Forceps-guided nuclear cleavage cataract extraction

We introduce a manual nuclear fragmentation technique, forceps-guided nuclear cleavage. A 5.5 to 7.0 mm superior scleral incision is started 1.5 mm posterior to the limbus. Two additional 1.0 mm paracenteses are made at 3 and 9 o'clock in clear cornea close to the limbus. A continuous curvilinear capsulorhexis (CCC) is created; in most cases, 4 to 5 radial relaxing incisions are made in the CCC. The anterior and equatorial cortex and epinucleus are removed with 2-handed irrigation/aspiration via the 2 paracenteses with the nucleus in the capsular bag. The nucleus is prolapsed into the anterior chamber. A nucleus hook is inserted via the 3 o'clock paracentesis and applied to the 6 o'clock nuclear equator to hold the nucleus. A nucleus cleaving forceps is inserted through the upper incision to the 12 o'clock equator of the nucleus and advanced to one-third depth of the nucleus. The forceps is relaxed while the nucleus is cleaved in half.

Sinus fracture--phacoemulsification technique for dense cataracts

A method of performing phacofracture of hard nuclei is presented. Following a central horizontal fracture into 2 hemisections, the phacoprobe is plunged into the inferior hemisection to create a sinus within its dense wall. The chopper/second instrument is placed into the sinus and force is applied along the lateral walls of the sinus. The phacoemulsification probe breaks it and splits the inferior hemisection into two quadrants. A similar method is employed for the superior-nuclear hemisection.

Comparative study of vitrectomy for dropped nucleus with and without the use of perfluorocarbon liquid. Clinical, electrophysiological and visual field outcomes

PURPOSE

To compare pars plana vitrectomy for dropped nucleus with and without perfluorocarbon liquid.

METHODS

24 eyes with dropped nucleus were randomized to undergo PPV with perfluorodecalin, (study, n=12) and without it (control, n=12). Visual acuity, IOP, visual evoked response and electroretinography were noted at study entry and up to 3 months after PPV. Humphrey perimetry was done at 3 months.

RESULTS

Final visual acuity was >20/60 in 75% of study eyes and 41.6% of controls. The two groups were statistically comparable with regard to the above parameters before PPV and during follow-up. The timing of vitrectomy did not significantly influence the final visual acuity. A higher rate of complications was seen in the control group.

CONCLUSIONS

Perfluorodecalin facilitated the procedure and possibly minimized complications, and was found to be safe for intraoperative use in terms of recovery of visual acuity, stable ERG and VER, and normal visual fields.

[Hard nucleus chopping technique for non-phacoemulsification in small-incision cataract surgery: two-knife chopping]

PURPOSE

To search for a practical nuclear chopping technique for non-phacoemulsification in small-incision cataract surgery.

METHODS

We designed two choppers for dividing nucleus in cataract surgery. We used them in our clinical practice of hard nuclear cataract surgery and thus improved the choppers constantly.

RESULTS

Two hundred and forty-six cases (246 eyes) of cataract with their nuclei being Grade III or harder were involved in our observation. Nucleus had been divide into two halves at one chopping and the nuclear halves were delivered through a 4.5 mm incision safely in all cases. Visual acuity was 0.5 or better in 189 eyes (73.8%), 232 eyes (94.9%) and 241 eyes (97.9%) one day, seven days and three months respectively after surgery. Complications included corneal edema near the incision in 12% eyes and folding of the Descemet membrane in 25% eyes.

CONCLUSION

Two-knife chopping technique has the advantages of reasonable design, small incision, little injury, no limitation by hard nucleus and easy manipulation. It is a practical and ideal chopping technique in non-phacoemulsification small-incision cataract surgery.

Photolysis using the Dodick-ARC laser system for cataract surgery

PURPOSE

To report the intraoperative and postoperative results of cataract surgery using a pulsed Q-switched neodymium:YAG (Nd:YAG) laser.

SETTING

Eye Clinic, Kreiskrankenhaus Bad Hersfeld, Germany.

METHODS

This prospective study involved 100 consecutive patients who had cataract surgery between October 1998 and May 1999. The patients were allocated to 3 groups based on the hardness of the nucleus using the LOCS III system: Group 1 (NO < or = 2.9), 48 patients; Group 2 (NO 3.0 to 3.9), 46 patients; Group 3 (NO > or = 4.0), 6 patients. Plasma was generated with a pulsed Q-switched Nd:YAG laser (ARC GmbH). A clear corneal incision of 1.25 mm provided access for the laser tip. An intraocular lens (CeeOn Edge [Pharmacia & Upjohn] or AcrySof [Alcon]) was implanted via a separate clear corneal incision. Intraoperative laser pulse rate and total energy were recorded. Preoperative and postoperative (2 days and 6 months) central cornea thickness was compared.

RESULTS

In all cases, the cataract was removed within an acceptable time without converting to the conventional phacoemulsification technique. Mean total energy was 1.97 J +/- 1.43 (SD) in Group 1, 3.37 +/- 1.59 J in Group 2, and 7.70 +/- 2.09 J in Group 3. No significant postoperative changes between preoperative and postoperative central pachymetry were seen in Groups 1 and 2; there was a 1.9% postoperative increase in central pachymetry in Group 3. This could be a consequence of the higher volume of intraoperative balanced salt solution and the prolonged procedure in this group. Six months postoperatively, there were no significant changes from the preoperative values.

CONCLUSION

Photolysis of the lens nucleus can be used safely and efficiently for nuclei with a hardness up to NO 3.9. The energy required for lens removal was 83% less than that required by phacoemulsification.

A retrospective study of patients with retained nuclear fragments after cataract extraction

PURPOSE

A registration and follow-up of patients who underwent pars plana vitrectomy after dislocated nuclear fragments to the vitreous following cataract extraction.

MATERIAL AND METHODS

A retrospective study of 125 patients referred to The National Hospital during the years 1991 to 1998. Phacoemulsification and extracapsular technique were used in 115 eyes and 10 eyes, respectively. A pars plana vitrectomy was performed within an average of 13 days (1-99 days) after cataract extraction. Average follow-up period was 9 months (0.5-35 months).

RESULTS

The visual acuity at follow-up was > or = 0.5 in 67 eyes (55.4%), <0.5->0.1 in 32 eyes (26.4%), and < or = 0.1 in 22 eyes (18.2%). The total number of retinal detachments was 26 (21.5%).

CONCLUSION

Retained nuclear fragments in the vitreous is a serious complication and most eyes achieve acceptable visual results.

Hydrodissection after nucleus fracture

We introduce a technique of hydrodissection that reduces capsular bag distension and thus lowers the risk of capsular block syndrome. In 100 consecutive cases in which this method was used for cataract surgery, no complications occurred. Postoperative best corrected visual acuity was better than 20/40 in 96% of patients.

Phaco-chop versus stop-and-chop nucleotomy for phacoemulsification

PURPOSE

To perform a comparative evaluation of phaco-chop versus stop-and-chop nucleotomy techniques of phacoemulsification.

SETTING

Dr. Rajendra Prasad Center for Ophthalmic Sciences, New Delhi, India.

METHODS

Forty eyes of 40 patients with immature senile cataract were included in the study. Twenty eyes each were randomly assigned to have phaco-chop (Group 1) or stop-and-chop (Group 2) nucleotomy during phacoemulsification. The main parameters were corneal endothelial count, effective phaco time, volume of infusion fluid used, central corneal pachymetry, best corrected visual acuity (BCVA), and intraoperative complications during nucleotomy. Follow-up visits were scheduled at 1, 4, and 12 weeks.

RESULTS

The mean effective phaco time was 27 seconds +/- 18 (SD) in Group 1 and 28 +/- 16 seconds in Group 2. The mean corneal endothelial cell loss was 6.89% and 7.17%, respectively, at the end of 12 weeks. The difference between groups was not significant. An anterior capsule tear occurred in 3 eyes in Group 1 and 1 eye in Group 2. All eyes achieved a BCVA of 20/20 at the end of 4 weeks. There were no significant between-group differences in any intraoperative or postoperative parameter.

CONCLUSIONS

The phaco-chop and the stop-and-chop nucleotomy techniques were equally efficacious for nuclear management during phacoemulsification.

Quarters extraction technique for manual phacofragmentation(1)

In the quarters extraction technique, the nucleus is manually split and the fragments then removed. A 5.5 to 6.5 mm sclerocorneal single-plane incision is made. After capsulorhexis, hydrodissection, hydrodelineation, and surface cortex aspiration, the edge of the nucleus is prolapsed into the anterior chamber. The front quarter of the nucleus is cut and removed with a nucleus puncher. A corner of the remaining three quarters of nucleus is wedged into the wound and rotated out with a claw vectis. Among the initial 120 cases, there were no posterior capsule ruptures, and the mean endothelial cell loss at 3 months was 8.7% +/- 6.5% (SD). Because there is no need to deeply insert instruments at the time of nuclear fragmentation, this technique can be performed safely and easily in most cases except in eyes with very large nuclei.