Effect of Minimising Ultrasound Power to 1% During Cataract Surgery on Corneal Endothelium. (OCTOPUS)

Standard Coaxial Microincision Cataract Surgery Versus Coaxial Microincision Cataract Surgery Using 1% Ultrasound in Immature Senile Cataract :a Corneal Endothelium Study

Coaxial microincision cataract surgery using 1% ultrasound is not inferior to standard coaxial microincision cataract surgery in patients of grade 0.1-6.0 immature senile cataract in terms of corneal endothelial safety.

Study Overview

• Status: Unknown
• Conditions: Cataract
• Intervention / Treatment: Procedure: one percent ultrasound power in CMICS; Procedure: 40 percent ultrasound power in CMICS

Detailed Description

Corneal endothelial damage and posterior capsular rupture are two most undesirable complications of cataract surgery, infact significant loss of endothelium can lead to corneal decompensation and loss of corneal clarity. However, some degree of endothelial cell loss is inevitable after any cataract surgery. A loss of 3.2%-23.2% has been shown in various studies since 1967. It is well known that during cataract surgery many different factors can generate endothelial damages, these include the impact of the nuclear fragments, the turbulence generated in anterior chamber and the volume of liquid. It is also related to the amount of ultrasonic energy used and the subsequent temperature rise, the contact with surgical instruments and the IOL during implantation. It also depends on the release of free radicals the length and features of incision,the surgical technique used . The risk of endothelial cell density loss is further enhanced when surgeons have to deal with high density cataract, shallow anterior chamber and old age.

Since the time Kelman introduced his technique of phacoemulsification, there has been constant and conscious effort on the part of phaco surgeons to reduce their phaco time by bringing some alteration or innovation in their personal technique or introducing new technologies for the procedure of phacoemulsification. Development of Laser emulsifier, SONAAR machines, introduction of cold phaco with modulations of ultrasound in the form of pulse, micropulse and bursts were achievements towards attaining this end and goal.

Coaxial microphacoemulsification is the standard phacoemulsification technique being practised globally for cataract extraction and on many occasions we intentionally do not use the phaco power either at all or fully as per the pre set limit. In fact the use of efficient fluidic controls and a chopper minimizes the use of phaco energy. If we could assess a zero/minimal ultrasound technique in a scientific setting we might achieve the desired goal without resorting to major modifications of instrumentation and machine. Coaxial MICS fully utilizes the advantages of small incision and provides the most comfortable platform for the surgeons using conventional phacoemulsification.

We imagined that most ideal setting would be introducing zero phaco power in the anterior chamber for emulsifying the nucleus as has been done already in case of Aqualase using warm fluid based system and Howard Fines new technique of mechanically emulsifying the lens with rotators(under investigation). For that we undertook a pilot study in 10 patients and performed coaxial microincision phacoemulsification, introducing the ultrasound power in incremental fashion during the surgery in each of the 10 patients till we could achieve the adequate aspiration of fluid and fragments .

At zero power the phacotip and tubing experienced repeated blockages with associated prolongation of surgical time,thus increment to one percent was made during the same sitting. To our surprise, the very first step of introducing 1% ultrasound power made all the difference.No further increments were required as all techniques of nuclear management and lens aspiration were conveniently possible at this setting.

The procedure of aspiration of fragments was smooth and continuous, it also caused a reduction in the surgical time in comparison to zero power phaco.The cases revealed less corneal endothelial trauma in comparison to conventional phacoemulsification using higher power settings. The most surprising observation was that we could dissemble the nucleus with any known technique of nucleus fragmentation(stop and chop, divide and conquer, phaco-chop) in almost all grades of cataracts .Possibly that high vaccum 300-350 is responsible for this nuclear fragmentation and not only the cavitational effects of ultrasound power.

Keeping all the other parameters uniform we wish to design an RCT to study the effect of eliminating phaco power. With this in view,this study compares the endothelial status in addition to various complications and visual outcome following standard coaxial microincision cataract surgery and coaxial microincision cataract surgery using 1% ultrasound.

• Study Type: Interventional
• Enrollment (Anticipated): 72
• Phase: Phase 3

Contacts and Locations

• Study Contact: Name: Taru Dewan, MS FRCSEd; Phone Number: 0091-9810673180; Email: tarudewan@hotmail.com
• Study Contact Backup: Name: Praveen K Malik, MS; Phone Number: 0091-9810405681; Email: praveenk002@yahoo.com

Study Locations

• India
  • Delhi
    • New Delhi, Delhi, India, 110001
      • Recruiting
      • Dr. R.M.L.Hospital,
      • Contact: Taru Dewan, MS,FRCSEd; Phone Number: 0091-9810673180; Email: tarudewan@hotmail.com
      • Contact: Praveen K Malik, MS; Phone Number: 009109810405681; Email: praveenk002@yahoo.com
      • Principal Investigator: Taru Dewan, MS FRCSEd

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 40 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

1. Patients of >40yrs will be included in the study.
2. Grade 0.1-6.0 (LOCS III grading) of senile cataract.

Exclusion Criteria:

1. Patients with pre-operative endothelial cell density count less than 1500cells/mm2.
2. All eye pathologies that can compromise the visual recovery.
3. Eyes with any kind of corneal dystrophy or corneal scars preventing visualisation of cataract for reliable grading.
4. Raised intraocular pressure (> 21 mmHg).
5. Previous intraocular surgery.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: one percent ultrasound; Co-axial MICS shall be performed in cases allocated to this arm .The ultrasound power shall be kept at one percent during the surgery.A note of effective phacotime,volume of fluid aspirated and any intraoperative complications shall be made.	Procedure: one percent ultrasound power in CMICS; Co-axial MICS shall be performed in cases allocated to this arm .The ultrasound power shall be kept at one percent during the surgery.A note of effective phacotime,volume of fluid aspirated and any intraoperative complications shall be made.; Other Names: OCTOPUS
Active Comparator: 40 percent ultrasound; Co-axial MICS shall be performed in cases allocated to this arm .The ultrasound power shall be kept at 40 percent during the surgery.A note of effective phacotime,volume of fluid aspirated and any intraoperative complications shall be made.	Procedure: 40 percent ultrasound power in CMICS; Co-axial MICS shall be performed in cases allocated to this arm .The ultrasound power shall be kept at 40 percent during the surgery.A note of effective phacotime,volume of fluid aspirated and any intraoperative complications shall be made.; Other Names: standard CMICS

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
change in endothelial cell count from baseline over time	Noncontact specular microscope (EM - 3000; TOMEY: VERSION 2A/OJ) will be used to calculate the endothelial cell density, coefficient of variation of cell size, percentage of hexagonal cells and corneal thickness before surgery and 1day, 1 week, 1, 3, 6, 9 and 12 months visits after surgery. 3 endothelial cell photographs will be taken at each visit and the mean cell count of three photographs will be calculated. Counts will be performed by an observer blinded to which procedure the patient had undergone. Endothelial cell loss will be calculated as a percentage of pre operative cell density	1 day,1week,months 1,3,6,9,12

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
change in Intraocular pressure from baseline	Intraocular pressure will be measured using applanation tonometer.	1day,1week,months1,3,6,9,12
visual acuity	snellens visual acuity will be converted to Logmar scale and recorded with and without spectacle correction	1 month
posterior capsular rupture	any incidence of posterior capsular rupture during surgery would be noted	day 0 of surgery

Collaborators and Investigators

• Sponsor: Dr. Ram Manohar Lohia Hospital
• Investigators: Principal Investigator: Taru Dewan, MS FRCSEd, Dr. R.M.L.Hospital,New Delhi,India

Study record dates

Study Major Dates

• Study Start: November 1, 2010
• Primary Completion (Anticipated): April 1, 2011
• Study Completion (Anticipated): April 1, 2012

Study Registration Dates

• First Submitted: December 6, 2010
• First Submitted That Met QC Criteria: December 13, 2010
• First Posted (Estimate): December 14, 2010

Study Record Updates

• Last Update Posted (Estimate): December 15, 2010
• Last Update Submitted That Met QC Criteria: December 14, 2010
• Last Verified: November 1, 2010

More Information

Terms related to this study

• Keywords: cataract,; phacoemulsification,; one percent ultrasound; endothelial cell density
• Additional Relevant MeSH Terms: Eye Diseases; Lens Diseases; Cataract
• Other Study ID Numbers: RMLH-002-EYE