Surface roughness after excimer laser ablation using a PMMA model: profilometry and effects on vision.
OBJECTIVE
To show that the limited quality of surfaces produced by one model of excimer laser systems can degrade visual performance with a polymethylmethacrylate (PMMA) model.


METHODS
A range of lenses of different powers was ablated in PMMA sheets using five DOS-based Nidek EC-5000 laser systems (Nidek Technologies, Gamagori, Japan) from different clinics. Surface quality was objectively assessed using profilometry. Contrast sensitivity and visual acuity were measured through the lenses when their powers were neutralized with suitable spectacle trial lenses.


RESULTS
Average surface roughness was found to increase with lens power, roughness values being higher for negative lenses than for positive lenses. Losses in visual contrast sensitivity and acuity measured in two subjects were found to follow a similar pattern. Findings are similar to those previously published with other excimer laser systems.


CONCLUSIONS
Levels of surface roughness produced by some laser systems may be sufficient to degrade visual performance under some circumstances.
Department of Optometry and Neuroscience, UMIST, Manchester, United Kingdom. s.a.naroo@aston.ac.uk
Shehzad A
SA
Naroo
W Neil
WN
Charman
D000328:Adult; D015350:Contrast Sensitivity / Q000502:physiology; D006801:Humans; D054018:Lasers, Excimer; D008875:Middle Aged; D008953:Models, Anatomic; D018903:Photorefractive Keratectomy; D019904:Polymethyl Methacrylate; D013499:Surface Properties; D014785:Vision, Ocular / Q000502:physiology*; D014792:Visual Acuity / Q000502:physiology
D019904:Polymethyl Methacrylate