Horizontal Chopping Research Articles

CHOPPING METHODS IN APPROACHING HARD CATARACT: OPTIONS AND RECOMMENDATION

Abstract
 Introduction & Objectives : Mature cataracts with hard-nuclear and soft-nuclear cataracts were different in their anatomical features and their management approach. Degeneration of zonules, loss of capsule and cortical liquefaction are often found in hard cataracts. Therefore, different approaches are required in this condition. Chopping methods have several advantages in managing the nucleus which plays a major part in cataract surgery. It lessened phaco power which minimized endothelial damage. The risk of intraoperative zonular dehiscence may also be lowered with chopping methods. Several chopping methods are widely accepted in approaching hard cataracts such as vertical chop, horizontal chop, crater and chop, drill and chop, stop and chop, and multilevel chop. Burst mode which requires high vacuum and power to chop and flow rates must be adequately comprehended by the surgeon in achieving the optimal result. This review discussed chopping methods in cataract surgery.
 Methods : Several chopping methods are widely accepted in approaching hard cataracts such as vertical chop, horizontal chop, crater and chop, drill and chop, stop and chop, and multilevel chop.
 Results : Burst mode which requires high vacuum and power to chop and flow rates must be adequately comprehended by the surgeon in achieving the optimal result.
 Conclusion : This review discussed chopping methods in cataract surgery.

"Stop & drop"- a modified "stop & chop" phacoemulsification technique for cataract surgery.

To introduce a novel technique termed "stop and drop" for creating the first crack in the initial hemi-nucleus, eliminating the need to slip a chopper under the anterior capsular rim during horizontal chopping, hence lowering the risk of capsular or zonular damage. Placing a blunt chopper tip on the upper surface of the hemisection proximal to the capsular edge and pressing it downward to initiate a crack in a pinching manoeuvre. Once a crack has formed, the chopper can slide to the side, widening the crack and assisting the phaco needle to pull out the first fragment. The technique was used in over 100 cases of cataracts successfully. No radial tear, posterior capsule rupture or zonulolysis occurred. "Stop and drop" is an effective and safe technique for performing phacoemulsification. It is not suitable for soft nuclei where the chopper will likely "cheese-wire" through the nuclear material.

Anterior Chamber Retained Lens Fragments After Cataract Surgery: A Case Series and Narrative Review.

IntroductionRetained lens fragments in the anterior chamber following cataract extraction (CE) with phacoemulsification are rare but can lead to significant patient morbidity. Our study aimed to identify risk factors associated with retained lens fragments.MethodsPatients who underwent cataract surgery and subsequently identified to have retained lens fragments in the anterior segment were included. Incidence per year, patient demographics, visual acuity, ocular biometrics, surgical technique, surgeon performing CE, and outcomes were collected retrospectively and compared to a control group.ResultsTwenty-four patients were identified with retained lens fragments, with an incidence of 0.10%. The mean age was 76 years ±6.72 (60–80) compared to 63 ±11.41 (22–86) in the control group (p <0.001). Patients with UDVA 20/150 or worse experienced a greater average improvement in visual acuity compared to patients with UDVA better than 20/150 (logMAR 0.46 vs logMAR 0.05). The mean intraocular pressures before (CE), after CE but before fragment removal, and following fragment removal were 14 mmHg ±2.59, 19 mmHg ±8.20, and 11 mmHg ±2.75, respectively. Twenty-two patients presented with inferiorly located fragments. Statistically significant biometrics include mean anterior chamber depth (3.1 mm ±0.37 vs 3.33 mm ±0.39, p = 0.01) and lens thickness (4.77 mm ±0.44 vs 4.35 mm ±0.44, p = <0.001). Yearly incidence rates per surgeon ranged from 0.00% to 0.85%. In 2003 and 2004, one surgeon had significantly higher incidence rates (0.31 and 0.40%) compared to the average combined rate of all surgeons throughout the study (0.10), with p values of 0.001 and 0.003, respectively. The mean number of days between CE and fragment removal was 26 ±40 (1–138).ConclusionIncreased patient age, shallow anterior chamber depth, and thick lens may be risk factors for retained lens fragments. There may be additional surgeon-specific risk factors. Phacoemulsification technique (Divide-and-Conquer versus Horizontal Chop) showed no significant difference.

Aligned chopping for full thickness fragmentation in hard cataracts

We describe a horizontal chopping technique to fracture the nucleus using an angled sharp edged chopper, thats enters the anterior chamber through a side port in a 30° angle to the main incision. Following the capsulorrhexis, the phaco tip is buried into the nucleus centrally, while the surgeon-bent chopper is placed behind the lens on the opposite side of the main incision. When moving the chopper towards the phaco tip, the angle allows a sharp clean cut of the hard nucleus, dividing it in 2 hemispheres and consequently further in smaller fragments.

Capsular tension ring assisted phacoemulsification of morgagnian cataract.

Purpose:To describe a novel technique of phacoemulsification in morgagnian cataract using capsular tension ring (CTR).Methods:This was a retrospective, non-comparative, clinical interventional study. Patients with hypermature morgagnian cataract who had undergone CTR-assisted phacoemulsification were included in the study. After capsulorhexis, CTR was inserted in a clockwise manner to stabilize the capsular bag in each case. Phacoemulsification was then performed using either horizontal chopping or vertical chopping. We have used the CTR in these cases without any obvious lens subluxation in order to perform safe emulsification of the nuclear pieces in the capsular bag. We have performed the procedure successfully in eleven eyes with hypermature morgagnian cataract.Results:The mean corrected distance visual acuity (CDVA) improved from 2.62 ± 0.25 Log MAR to 0.35 ± 0.28 Log MAR at 3 months postoperatively (P = 0.00008). Total nine out of 11 patients gained CDVA of 20/40 or better at 3 months postoperatively. No intraoperative complications such as posterior capsular rupture, zonular dialysis, iris trauma, vitreous loss were noted. The mean endothelial cell loss was 148.82 ± 41.52 cells/mm2 after 3 months of surgery.Conclusion:The main culprit for intraoperative complications during phacoemulsification in a morgagnian cataract is the vulnerable capsular bag. Following insertion of a CTR after capsulorhexis, the bag becomes stable and the subsequent steps of the surgery become uneventful, thereby, preventing any further complications.

Rotary Chop: A New Technique for Teaching Chop and Tackling Mature Cataracts.

IntroductionHere we describe a new cataract chop technique that is most valuable for two groups of ophthalmologists: (1) experienced surgeons encountering challenging nuclear fragmentation due to mature cataracts or zonulopathies, and (2) inexperienced surgeons wishing to develop skills necessary for chopping techniques.MethodsWe have termed this new method “rotary chop,” since the partial thickness pilot holes created by the phacoemulsification (phaco) tip around the periphery of the nucleus produce a rotary phone dial appearance on the surface of the cataract. By creating these pilot holes, the surgeon is able to easily place the chopper deep into the body of the nucleus, avoiding the need to apply vertical piercing force to the nucleus.ResultsThe patient in the technical video had a 4+ nuclear sclerosis cataract. The preoperative vision in this eye was counting fingers at 2 feet with no improvement with refraction. On postoperative day 1, visual acuity had improved to 20/80 . By postoperative week 1, best-corrected visual acuity was 20/20 (20/25-2 uncorrected).ConclusionThis method avoids unnecessary zonular stress. Additionally, inexperienced surgeons using this technique during routine cataract surgery are able to quickly master the movements necessary for both vertical and horizontal chop in a safer environment.Electronic supplementary materialThe online version of this article (10.1007/s40123-020-00249-7) contains supplementary material, which is available to authorized users.

Scoop and chop - A modified phaco-chop technique for pseudoexfoliation and cataract.

PURPOSE:The purpose is to evaluate the results of the modified direct phaco-chop technique of cataract surgery in eyes with pseudoexfoliation.METHODS:All patients with pseudoexfoliation and visually significant cataract with normal intraocular pressure (IOP) and optic nerve that underwent cataract surgery by the same surgeon using Infiniti®, OZil® Torsional handpiece (Alcon Labs), were included for this retrospective hospital-based study. Direct vertical or horizontal chop technique was used in all cases with parameters set as required for quadrant removal with high vacuum after the initial cleanup of cortex under the capsulorhexis. To allow better visualization of the hardness of the nucleus core, the sides of the lens were scooped out a central well with vacuum with maximum chopping done centrally within the rhexis as the first step to enable better assessment of the depth of burying the chopper for direct chop. Intraoperative details recorded and analyzed included ultrasound time and cumulative dissipated energy. The mean visual acuity and IOP before and after surgery were recorded at 1 day, 1 week, and 1 month. Complications during or after surgery were noted.RESULTS:A total of 138 patients with a mean age of 62 ± 6.7 years underwent phachop technique of phacoemulsification for nuclear cataract grades of nuclear sclerosis 2–4 with significant improvement in visual acuity from baseline (0.26) to 3 months (0.82), P < 0.001. The mean ultrasound torsional amplitude and cumulative dissipated energy (CDE) were greater for brown cataract of grading >3, P = 0.02. A total of 8 patients had intraoperative zonular dialysis in 1 quadrant (none in >1 quadrant), which was not associated with intraoperative vitreous prolapse in 6 eyes.CONCLUSIONS:Direct modified phaco-chop technique may be a safe technique in pseudoexfoliation due to minimal zonular stress with successful outcomes and reduced complications.

Application of vertical chop combined with horizontal chop in hard nuclear cataract surgery

Objective To evaluate the efficacy of vertical chop combined with horizontal chop in hard nuclear cataract surgery. Methods A retrospective study. Total of 86 eyes of 86 patients with senile cataract were randomly divided into two groups, and all nuclear classification ranged from IV to V. Group A, 43 patients, received vertical chop combined with horizontal chop. Group B, 43 patients, received phacoemulsification with high vacuum splitting. The efficacy were compared between the two groups. Results The ultrasonic time (UST) was (67.77±14.68) s of group A and (103.09±44.89) s of group. The cumulative dissipated energy (CDE) was 35.33±12.75 of group A and 41.25±14.35 in group B. The difference in UST and CDE were significant statistically between the two groups (P 0.3 occupied 86.05 % in group A and 67.44 % in group B (P=0.04). The corneal edema at 1 day postoperatively in group A was lower than that in group B, the difference was statistically significant between the two groups (P=0.03). The difference in degree of corneal edema at 7 days after surgery was not statistically significant between the two groups. The corneal endothelial cells (CECs) in 1 month postoperatively was (2 371.30±179.02)/mm2 in group A and (2 157.80±156.46)/mm2 in group B(P<0.01). The loss rate of CECs was (8.73±3.74)% in group A and (15.41±3.54)% in group B(P<0.01). Conclusion Application of vertical nuclear chop combined with horizontal nuclear chop in hard nuclear cataracts surgery is effective. Key words: Cataracts, hard nuclear; Chop, vertical; Chop, horizontal

Phaco-nucleotomy techniques in management of pseudoexfoliation syndrome.

Pseudoexfoliation syndrome is a common clinically important systemic condition characterized by the pathological production and accumulation of an abnormal fibrillar extracellular material in many intraocular and extra ocular tissues. Many studies have shown that pseudoexfoliation syndrome patients have higher rates of intraoperative complications during cataract surgery compared to the patients without it. To compare Phaco-chop and Divide and Conquer techniques of phacoemulsification, in the management of pseudoexfoliation syndrome in terms of intraoperative complications. It is a hospital based prospective study of 90 patients with cataract and pseudoexfoliation syndrome attending ophthalmology outpatient department in our hospital. The mean age of patients in the study was 61.7 years with equal number of unilateral and bilateral cases. Intra operative complications noted in vertical chopping technique was only pupil constriction in 6.7%, no other complications were seen in this technique, whereas in horizontal chopping, 13.3% had pupil constriction, 6.7% had difficulty in chopping, 3.3% had zonular dehiscence and 3.3% had posterior capsular rent . In divide and conquer technique 16.7% had pupil constriction, 10% had difficulty in trenching, 3.3% had posterior capsular rent. Almost all the patients (97.8%) were implanted with intraocular lens after employment of various surgical modifications. Vertical chopping techniques scores over horizontal chopping and divide and conquer technique of phacoemulsification with good surgical outcome because of less complications.

Corneal Affection in Divide and Conquer versus Horizontal Chopping in Phacoemulsification

Corneal Affection in Divide and Conquer versus Horizontal Chopping in Phacoemulsification

Lift and crack technique for risky cataract cases

We describe a technique to manage dense cataract cases. After a capsulorhexis of 6.0 to 7.0 mm diameter has been created, the phaco tip is inserted into the nucleus centrally and high vacuum is used to lift the nucleus and elevate it with a tilt to protrude outside the capsular bag distally. The chopper is used to segment the nucleus centripetally, starting from the lens equator or just behind, without applying stress to the capsular bag or zonules. Further phacoemulsification is maintained by holding the nucleus centrally and chopping it into smaller triangular sectoral pieces. In this horizontal chopping technique, which is done just outside the capsular bag, grasping the nucleus in the center and elevating it with high vacuum instead of depressing one edge of the nucleus to elevate the other edge prevents additional stress to the capsule and zonules. Neither author has a financial or proprietary interest in any material or method mentioned.

Double Extra Sharp Chopper Increase Efficacy of Phacoemulsification for Hard Mature Cataract Surgery

Objective: To assess the efficacy and safety of a modified double extra sharp chopper for removal of hard cataracts. Design: Prospective non-comparative interventional clinical study. Participants: Forty eyes from 25 patients with hard mature cataract grades 3-4. Methods: The pre-modified Koch chopper was sharpened under the slit lamp to become extra sharp at the tip and inside the edge and 2 mm in length. Patients with hard mature cataract grades 3-4 (grade 4 being the hardest) underwent phacoemulsification by single surgery and were analyzed prospectively. Results: The mean effective phaco time was 23.73 ± 5.75 seconds. Minimal power was facilitated by using horizontal chopping using a self-made double extra sharp chopper. No resistance was encountered while moving the chopper, regardless of cataract persistency. Preoperative BCVA were count fingers (47%), hand movement (35%), and light perception (18%). Postoperative BCVA on day 1and day 7 were 0.57 and 0.95, respectively. There was no difference of effective phaco time among nuclear hardness (P = 0.467), which represent the effectiveness of the extra sharp chopper. Conclusions: The double extra sharp chopper facilitated a safe and rapid visual rehabilitation and maximal subject comfort when doing phacoemulsification for hard mature cataracts.

Cross chop: Modified rotationless horizonal chop technique for weak zonules

Cross chop is a modified horizontal chop technique that enables safe and efficient lens disassembly without torquing the lens within the capsular bag.

Obtaining shorter regular expressions from finite-state automata

We consider the use of state elimination to construct shorter regular expressions from finite-state automata (FAs). Although state elimination is an intuitive method for computing regular expressions from FAs, the resulting regular expressions are often very long and complicated. We examine the minimization of FAs to obtain shorter expressions first. Then, we introduce vertical chopping based on bridge states and horizontal chopping based on the structural properties of given FAs. We prove that we should not eliminate bridge states until we eliminate all non-bridge states to obtain shorter regular expressions. In addition, we suggest heuristics for state elimination that leads to shorter regular expressions based on vertical chopping and horizontal chopping.

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.