PASCAL Laser Platform Produces Less Pain Responses Compared To Conventional Laser System

December 30, 2015 updated by: Umit Ubeyt INAN, Kocatepe University

An Observational Prospective Study of Comparing Pain Responses With Pattern Laser Platform and Conventional Laser System During the Panretinal Photocoagulation in Proliferative Diabetic Retinopathy

The aim of this study is to compare the severity of expressed pain scores in patients with PDR who underwent either PASCAL or conventional laser and to assess the association between patient characteristics and severity of pain.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Proliferative diabetic retinopathy (PDR) is a severe complication of diabetes mellitus characterized by new vessel formation in the retina and optic disc. Tight glycemic control and laser treatment in the early phases of the disease may slow the progression of PDR. Panretinal photocoagulation (PRP) is a laser-based treatment modality that destroys the outer retina layers and thereby improves the oxygen supply of the inner retina. During the following years, sequential improvements took place, including introduction of yellow, green, and diode lasers with various advantages of each wavelength.

In 2006, a novel semi-automatic and multi-shot photocoagulator called as PASCAL (Pattern scan laser, Opti-Medica Corp., Santa Clara, California, USA) was introduced with a reduction in pulse duration of each laser spot from typical 100 ms down to 10-30 millisecond. Compared with the conventional laser, shorter pulses have been shown to significantly reduce the risk of damage to the adjacent retinal tissues.

Almost all patients experience pain during PRP. While some patients may tolerate the pain, the majority does not. One study reported that 64.1% of patients did not complete treatment due to pain and therefore had an increased risk of vision loss. To improve patient compliance, several anesthetic and analgesic techniques such as peribulbar anesthesia, oral anesthesia and topical eye drops have been used. The patient comfort, and thus compliance, may be improved by using the shorter exposure burns, avoiding red or infrared wavelengths with deeper penetration, and by decreasing overall treatment time.

The aim of the current study was to compare the severity of expressed pain scores in patients with PDR who underwent either PASCAL or conventional laser.

As a method of this study, both eyes were treated within the same session and while one eye was treated with PASCAL laser, the other was treated with conventional laser (ELLEX Integre, Adailade, Australia) with 30 minutes resting intervals. To avoid a bias about orientation or becoming accustomed to laser procedure, PASCAL laser was performed in the first eyes in half of the patients (14 patients) and conventional laser was performed in the first eyes in the other half of the patients randomly. While the spot size used to obtain a white-grayish spot on the retina was 200-400 µm in both PASCAL and conventional laser, the pulse duration was 100 ms with conventional laser and 30ms with PASCAL laser. In order to accurately and reliable compare the grade of pain between each procedures, the retinal areas and total number of spots were standardized. Similar numbers of laser spots were created by two laser systems in same retinal quadrants in both eyes. Ten minutes after the procedure ended the severity of pain was assessed using a verbal rating scale and a visual analog scale (VAS). In the verbal scale the patient rates the pain on a Likert scale verbally, e.g. "none", "mild pain", "moderate pain", "severe pain" or "very severe pain" in five grading system (0-4) and in the VAS they specify the severity of pain by indicating a position along a continuous line from 0 to 10. Using these scores, relationship between severity of pain and patient characteristics including history of prior PRP treatment (experience), gender and duration of diabetes mellitus were assessed. Patients were assigned either in the experienced or non-experienced groups depending on history of prior PRP.

Study Type

Interventional

Enrollment (Actual)

30

Phase

  • Not Applicable

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Patients (>18 years) with type 1 or 2 diabetes and bilateral high-risk proliferative diabetic retinopathy (PDR)

Exclusion Criteria:

  • Patients with a history of focal/grid photocoagulation, a history of orbital trauma, orbital infection or surgery, those with corneal or lens opacities, those with vitreous hemorrhage and non-compliant patients

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: TREATMENT
  • Allocation: RANDOMIZED
  • Interventional Model: CROSSOVER
  • Masking: NONE

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
ACTIVE_COMPARATOR: PASCAL group
Patients undergone PASCAL laser photocoagulation
Device: PASCAL laser
A novel semi-automatic and multi-shot photocoagulator called as PASCAL (Pattern scan laser, Opti-Medica Corp., Santa Clara, California, USA) was introduced with a reduction in pulse duration of each laser spot from typical 100 ms down to 10-30 millisecond. Compared with the conventional laser, shorter pulses have been shown to significantly reduce the risk of damage to the adjacent retinal tissues. One eye was treated with PASCAL laser, the other was treated with conventional laser with 30 minutes resting intervals. To avoid a bias about orientation or becoming accustomed to laser procedure, PASCAL laser was performed in the first eyes in half of the patients (14 patients) randomly.
ACTIVE_COMPARATOR: Conventional group
Patients undergone conventional laser photocoagulation
Device: Conventional laser
Maintaining of good glycemic regulation and performing panretinal laser photocoagulation (PRP) with conventional laser device (ELLEX Integre, Adailade, Australia) when it is indicated are evidence based effective methods for proliferative diabetic retinopathy.One eye was treated with conventional laser, the other was treated with PASCAL laser with 30 minutes resting intervals. To avoid a bias about orientation or becoming accustomed to laser procedure, conventional laser was performed in the first eyes in half of the patients (14 patients) randomly.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Verbal Score for pain
Time Frame: 3 months
Verbal Score for pain was measured as units on the scale 10 minutes after the completion the laser procedure.
3 months
Visual analog score for pain
Time Frame: 3 months
Visual Analog Score for pain was measured as units on the scale 10 minutes after the completion the laser procedure.
3 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Kocatepe University

Investigators

  • Principal Investigator: Umit U Inan, M.D, Kocatepe University Medical School Department of Ophthalmology

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

May 1, 2014

Primary Completion (ACTUAL)

July 1, 2014

Study Completion (ACTUAL)

June 1, 2015

Study Registration Dates

First Submitted

December 19, 2015

First Submitted That Met QC Criteria

December 30, 2015

First Posted (ESTIMATE)

January 1, 2016

Study Record Updates

Last Update Posted (ESTIMATE)

January 1, 2016

Last Update Submitted That Met QC Criteria

December 30, 2015

Last Verified

December 1, 2015

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 0112S299

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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