a safety and effectiveness study of prk using the allegretto wave® eye-q excimer laser system

Conditions: Myopia; Astigmatism

Summary: the purpose of this study is to evaluate the safety and effectiveness of the allegretto wave eye-q excimer laser system for the reduction of myopia with or without astigmatism in subjects undergoing photorefractive keratectomy (prk) treatment.

this was a prospective, multi-center, single group study. subjects underwent bilateral prk in which the second eye was treated no sooner than 1 week and no later than 30 days after the first eye's prk treatment. subjects were followed for 2 years after surgery. the protocol underwent 4 amendments. the key differences between the protocol versions were clarifications of the planned analyses and adverse event reporting procedures. there were no changes in the inclusion and exclusion criteria or non-adverse event related study assessments between the protocol versions 1-5. refractive stability of manifest refraction spherical equivalent (mrse) and manifest refractive cylinder was defined as established when: * at least 95% of the treated eyes had a change ≤ 1.0 diopter between manifest refractions performed at any 2 manifest refractions at least 3 months apart * the mean rate of change, as determined by a paired analysis, was ≤ 0.5 diopter per year (0.04 d/month) over the same time period * the mean rate of change decreased monotonically over time, with a projected asymptote of zero or a rate of change attributable to normal aging * the 95% confidence interval for the mean rate of change included zero or a rate of change attributable to normal aging. refractive stability was assessed for pairs of visits within an interval and was defined to occur at the latter time point of the first interval at which stability was achieved. in the final amendment to the protocol, 3 secondary objectives were made co-primary in response to agency comments. all endpoints and analyses were modified to match.

Eligibility criteria:
inclusion criteria: * subjects desiring refractive correction of myopia up to -6.00 diopter (d) sphere with or without astigmatism 0 to -3.00 d and up to -6.00 d manifest refraction spherical equivalent (mrse) at the spectacle plane measured by manifest refraction; * minimum best spectacle corrected visual acuity (bscva) in the treated eye of 20/25; * uncorrected visual acuity (ucva) 20/40 or worse in the treated eye; * less than 0.75 d spherical equivalent (se) difference between cycloplegic and manifest refractions; * stable refraction (within ± 0.5 d), as determined by mrse for a minimum of 12 months prior to surgery; * demonstrated stable refraction for contact lens wearers, as specified in protocol; * signed informed consent document; * willing and able to comply with schedule for follow-up visits; * other protocol-defined inclusion criteria may apply. exclusion criteria * females who are pregnant, lactating, or planning a pregnancy during the time course of the study, or have another condition associated with the fluctuation of hormones that could lead to refractive changes; * participation in other clinical trials during this study; * acute or chronic disease or illness that would increase the operative risk or confound the outcomes of the study; * dry eye syndrome as determined by the short questionnaire for dry eye syndrome; * systemic medications that may confound the outcome of the study or increase the risk to the subject by affecting wound healing or tissue repair, including, but not limited to steroids, antimetabolites, immune response modifying drugs, etc.; * nystagmus or any other condition that would prevent a steady gaze during the prk treatment or other diagnostic tests; * ocular condition that may predispose the subject to future complications; * previous intraocular or corneal surgery; * subjects who desire to have monovision; * a known sensitivity to medications used for study procedures, including prk; * presence or history of any condition or finding that makes the subject unsuitable as a candidate for prk or study participation or may confound the outcome of the study, in the opinion of the investigator; * other protocol-defined exclusion criteria may apply.

Keywords: prk myopia astigmatism