Target detection in infrared images after wavefront-guided and wavefront-optimized PRK and LASIK

Abstract

Purpose : To assess the ability of U.S. military servicemembers to detect targets in infrared images before and after undergoing wavefront-guided (WFG) and wavefront-optimized (WFO) photorefractive keratectomy (PRK) and LASIK.

Methods : A total of 53 U.S. military servicemembers (mean age 29.9 ±5.5 years) electing to undergo either PRK or LASIK for myopia with or without astigmatism (mean manifest refractive spherical equivalent -3.78 ±1.44 diopters) were randomized to undergo WFG or WFO treatment. WFG treatment was performed using the VISX CustomVue STAR S4 IR and WFO with Wavelight Allegretto Wave EyeQ. In addition to clinical tests, the participants underwent computer-based experiments preoperatively (with optical correction) and at 6 weeks and 6 months postoperatively (6M PO) (without correction) assessing their ability to detect targets of military interests during wide field of view, long range search process: 1) mid-wave (MW) infrared images of human targets; and 2) MW and long-wave (LW1 and LW2) infrared images of combat vehicle targets. The probability of detection (Pd) for each experiment was calculated and the treatment groups were compared. Associations between postop target detection performance and clinical outcomes were also determined.

Results : The participants underwent either WFG PRK (n=14), WFG LASIK (12), WFO PRK (13) or WFO LASIK (14). All treated eyes except for one WFO PRK-treated eye achieved uncorrected distance visual acuity of 20/20 or better at 6M PO. In detecting human targets, there was no significant difference in Pd over a period up to 6M PO among the treatment groups (p=0.55). There was also no significant difference in Pd over time for detecting combat vehicle targets whether the targets were MW infrared images (p=0.91) or LW infrared images (LW1, p=0.52; LW2, p=0.71). At 6M PO, UDVA, MSE and the type of surgery were significantly associated with the Pd for human targets (R²=0.61, p=0.035) but not with the Pd for vehicle targets (p>0.126).

Conclusions : U.S. military servicemembers undergoing PRK or LASIK with either WFG or WFO technology for myopia or myopic astigmatism appear to benefit from their treatment, eliminating the need for corrective lenses while maintaining their ability to perform visual discrimination tasks. The outcomes of surgery appear to be strongly associated with their ability to detect human targets.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.