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

Diabetic Retinopathy Clinical Trial

Official title:

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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT02645383
• Other study ID #: 0112S299
• Status: Completed
• Phase: N/A
• First received: December 19, 2015
• Last updated: December 30, 2015
• Start date: May 2014
• Est. completion date: June 2015

Study information

• Verified date: December 2015
• Source: Kocatepe University
• Contact: n/a
• Is FDA regulated: No
• Health authority: Turkey: Ethics Committee
• Study type: Interventional

Clinical Trial Summary

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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 30
• Est. completion date: June 2015
• Est. primary completion date: July 2014
• Accepts healthy volunteers: No
• Gender: Both
• Age group: 18 Years and older

Eligibility

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 Design

Allocation: Randomized, Intervention Model: Crossover Assignment, Masking: Open Label, Primary Purpose: Treatment

Related Conditions & MeSH terms

• Diabetic Retinopathy
• Retinal Diseases

Intervention

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.
• 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.

Locations

Country	Name	City	State
n/a

Sponsors (1)

Lead Sponsor	Collaborator
Kocatepe University

References & Publications (12)

Aiello LP, Gardner TW, King GL, Blankenship G, Cavallerano JD, Ferris FL 3rd, Klein R. Diabetic retinopathy. Diabetes Care. 1998 Jan;21(1):143-56. Review. — View Citation

Al-Hussainy S, Dodson PM, Gibson JM. Pain response and follow-up of patients undergoing panretinal laser photocoagulation with reduced exposure times. Eye (Lond). 2008 Jan;22(1):96-9. Epub 2007 Nov 23. — View Citation

Alvarez-Verduzco O, Garcia-Aguirre G, Lopez-Ramos Mde L, Vera-Rodriguez S, Guerrero-Naranjo JL, Morales-Canton V. Reduction of fluence to decrease pain during panretinal photocoagulation in diabetic patients. Ophthalmic Surg Lasers Imaging. 2010 Jul-Aug;4 — View Citation

Blumenkranz MS, Yellachich D, Andersen DE, Wiltberger MW, Mordaunt D, Marcellino GR, Palanker D. Semiautomated patterned scanning laser for retinal photocoagulation. Retina. 2006 Mar;26(3):370-6. — View Citation

Feman SS, Chen J, Burroughs TE. Change in diabetic panretinal photocoagulation incidence. Ophthalmic Surg Lasers Imaging. 2012 Jul 1;43(4):270-4. doi: 10.3928/15428877-20120618-02. — View Citation

Jain A, Blumenkranz MS, Paulus Y, Wiltberger MW, Andersen DE, Huie P, Palanker D. Effect of pulse duration on size and character of the lesion in retinal photocoagulation. Arch Ophthalmol. 2008 Jan;126(1):78-85. doi: 10.1001/archophthalmol.2007.29. — View Citation

Mainster MA. Decreasing retinal photocoagulation damage: principles and techniques. Semin Ophthalmol. 1999 Dec;14(4):200-9. Review. — View Citation

Muqit MM, Marcellino GR, Gray JC, McLauchlan R, Henson DB, Young LB, Patton N, Charles SJ, Turner GS, Stanga PE. Pain responses of Pascal 20 ms multi-spot and 100 ms single-spot panretinal photocoagulation: Manchester Pascal Study, MAPASS report 2. Br J O — View Citation

Nagpal M, Marlecha S, Nagpal K. Comparison of laser photocoagulation for diabetic retinopathy using 532-nm standard laser versus multispot pattern scan laser. Retina. 2010 Mar;30(3):452-8. doi: 10.1097/IAE.0b013e3181c70127. — View Citation

Schuele G, Rumohr M, Huettmann G, Brinkmann R. RPE damage thresholds and mechanisms for laser exposure in the microsecond-to-millisecond time regimen. Invest Ophthalmol Vis Sci. 2005 Feb;46(2):714-9. — View Citation

Wu WC, Hsu KH, Chen TL, Hwang YS, Lin KK, Li LM, Shih CP, Lai CC. Interventions for relieving pain associated with panretinal photocoagulation: a prospective randomized trial. Eye (Lond). 2006 Jun;20(6):712-9. Epub 2005 Jul 8. — View Citation

Zakrzewski PA, O'Donnell HL, Lam WC. Oral versus topical diclofenac for pain prevention during panretinal photocoagulation. Ophthalmology. 2009 Jun;116(6):1168-74. doi: 10.1016/j.ophtha.2009.01.022. Epub 2009 Apr 19. — View Citation

* Note: There are 12 references in all — Click here to view all references

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Verbal Score for pain	Verbal Score for pain was measured as units on the scale 10 minutes after the completion the laser procedure.	3 months	No
Primary	Visual analog score for pain	Visual Analog Score for pain was measured as units on the scale 10 minutes after the completion the laser procedure.	3 months	No