Efficacy of the Wavefront Optimized (WFO) Profile in Non-anterior Astigmatisms

NCT ID: NCT01432834

Last Updated: 2017-01-18

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 74 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2010-04-30
• Study Completion Date: 2011-04-30

Brief Summary

The purpose of the study was to assess the efficacy of the Allegretto Wave excimer laser and the wavefront optimized ablation profile in correcting primarily non-anterior astigmatism faults, following laser in-situ keratomileusis (LASIK) and photorefractive keratectomy (PRK).

Detailed Description

Different optical components of the eye contribute to the total astigmatism error.In specific, the anterior corneal surface is responsible for the anterior component of astigmatism fault (anterior astigmatism), while the posterior corneal surface and the lens are responsible for the posterior one (posterior astigmatism).

Regarding our study, 74 refractive surgery candidates were recruited. Only one eye from each candidate was randomly enrolled in the study. Of them, 40 eyes underwent LASIK treatment (LG group), while 34 eyes underwent PRK treatment (PG group). The Allegretto Wave excimer laser (software version: 2.020 / WaveLight AG, Erlangen, Germany) was used for the ablation in all groups. Preoperatively, the ocular residual astigmatism (ORA) was calculated for each eye, according to which each astigmatism fault was characterized as primarily anterior or non-anterior.ORA is the vectorial value of astigmatism arising from non-anterior sources. Its amount on total astigmatism (R) is determined by the magnitude ratio ORA/R. Ratios below 1 indicate primarily anterior astigmatism, while ratios above 1 indicate primarily non-anterior astigmatism. 20 LG eyes and 16 PG eyes presented primarily anterior astigmatism (LG-A and PG-A subgroups, respectively), while 20 LG eyes and 18 PG eyes demonstrated primarily non-anterior astigmatism (LG-NA and PG-NA subgroups, respectively). Postoperatively, vector analysis of astigmatism correction was conducted; The following indexes were calculated: a) Correction index (CI), b) Difference vector (DV) and c) Index of Success (IOS).

Conditions

Astigmatism

Study Design

• Allocation Method: NON_RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: NONE

Study Groups

LASIK group (LG group)

Volunteers of this group received LASIK treatment.

Group Type: OTHER

Laser in situ keratomileusis (LASIK)

Intervention Type: OTHER

During LASIK treatments the Carriazo-Pendular microkeratome (SCHWIND eye-tech-solutions GmbH \& Co.KG, Kleinostheim, Germany) with 130μm cutting head was used for the creation of the flap. The normal value of the negative pressure of the suction ring was between 600-620 mmHg and the velocity of the head movement was constant (3mm/sec). The hinge was created at the 12 o'clock position. The Allegretto Wave excimer laser (software version: 2.020 / WaveLight AG, Erlangen, Germany) was used for all ablations. Attempted ablations were modified according to the "S001 Wellington" nomogram for the "wavefront optimised" protocol.

PRK group (PG group)

Volunteers of this group received PRK treatment

Group Type: OTHER

Photorefractive keratectomy (PRK)

Intervention Type: OTHER

The same surgical procedure was applied to all PG participants that included: Instillation of proparacaine hydrochloride 0.5% drops for topical anaesthesia, application of a sponge saturated with 10% alcohol to the central cornea for 20-30 seconds and subsequent de-epithelialization by means of a hockey knife.The Allegretto Wave excimer laser (software version: 2.020 / WaveLight AG, Erlangen, Germany) was used for all ablations. Attempted ablations were modified according to the "S001 Wellington" nomogram for the "wavefront optimised" protocol. A soft therapeutic lens was applied until complete re-epithelialization of the cornea was detected.

Interventions

Laser in situ keratomileusis (LASIK)

During LASIK treatments the Carriazo-Pendular microkeratome (SCHWIND eye-tech-solutions GmbH \& Co.KG, Kleinostheim, Germany) with 130μm cutting head was used for the creation of the flap. The normal value of the negative pressure of the suction ring was between 600-620 mmHg and the velocity of the head movement was constant (3mm/sec). The hinge was created at the 12 o'clock position. The Allegretto Wave excimer laser (software version: 2.020 / WaveLight AG, Erlangen, Germany) was used for all ablations. Attempted ablations were modified according to the "S001 Wellington" nomogram for the "wavefront optimised" protocol.

Intervention Type: OTHER

Photorefractive keratectomy (PRK)

The same surgical procedure was applied to all PG participants that included: Instillation of proparacaine hydrochloride 0.5% drops for topical anaesthesia, application of a sponge saturated with 10% alcohol to the central cornea for 20-30 seconds and subsequent de-epithelialization by means of a hockey knife.The Allegretto Wave excimer laser (software version: 2.020 / WaveLight AG, Erlangen, Germany) was used for all ablations. Attempted ablations were modified according to the "S001 Wellington" nomogram for the "wavefront optimised" protocol. A soft therapeutic lens was applied until complete re-epithelialization of the cornea was detected.

Intervention Type: OTHER

Other Intervention Names

Allegretto Wave excimer laser (software version: 2.020 / WaveLight AG, Erlangen, Germany); Carriazo-Pendular microkeratome (SCHWIND eye-tech-solutions GmbH & Co.KG, Kleinostheim, Germany); Allegretto Wave excimer laser (software version: 2.020 / WaveLight AG, Erlangen, Germany)

Eligibility Criteria

Inclusion Criteria

• astigmatism fault

Exclusion Criteria

• previous incisional eye surgery
• evidence of any type of corneal pathology
• evidence of any type of optic neuropathy
• history of optic neuropathy
• diabetes mellitus

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Democritus University of Thrace

OTHER

Sponsor Role: lead

Responsible Party

Georgios Labiris

Senior Lecturer of Ophthalmology

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

Eye Institute of Thrace (EIT)

Alexandroupoli, , Greece

Countries

Greece

References

Labiris G, Gatzioufas Z, Giarmoukakis A, Sideroudi H, Kozobolis V. Evaluation of the efficacy of the Allegretto Wave and the Wavefront-optimized ablation profile in non-anterior astigmatisms. Acta Ophthalmol. 2012 Sep;90(6):e442-6. doi: 10.1111/j.1755-3768.2012.02463.x. Epub 2012 Jun 13.

Reference Type: RESULT

PMID: 22690672 (View on PubMed)

Other Identifiers

23/29-07-11

Identifier Type: -

Identifier Source: org_study_id