Comparison of postoperative higher-order aberrations and contrast sensitivity: tissue-saving versus conventional photorefractive keratectomy for low to moderate myopia.
OBJECTIVE
To assess the efficacy, predictability, safety, contrast sensitivity, higher-order aberrations (HOAs), and patient satisfaction after tissue-saving photorefractive keratectomy (PRK) and conventional PRK.


METHODS
Department of Ophthalmology, Farabi Eye Hospital, Tehran Medical University, Tehran, Iran.


METHODS
Comparative case series.


METHODS
This prospective study evaluated eyes with low to moderate myopia that had PRK with a Technolas 217z excimer laser. Patients were randomly assigned to have surgery using a conventional algorithm (PlanoScan) or a tissue-saving algorithm (Zyoptix). Contrast sensitivity, HOAs, and patient satisfaction were analyzed preoperatively and 1, 3, and 6 months postoperatively.


RESULTS
The conventional group comprised 42 eyes (21 patients) and the tissue-saving group, 62 eyes (31 patients). At 6 months, all eyes in both groups were within ±0.50 diopter of the attempted correction and had an uncorrected distance visual acuity of 20/25 or better. However, the tissue-saving group had a statistically significantly greater increase in the mean root mean square of total HOAs and more induced spherical aberration than the conventional group (P<.05). There was no significant difference between the 2 groups in mesopic or photopic contrast sensitivity. The level of satisfaction after surgery was the same in the 2 groups.


CONCLUSIONS
Although the conventional and tissue-saving algorithms for PRK were both safe and effective in treating low to moderate myopia, tissue-saving PRK induced a greater increase in HOAs than conventional PRK; this may be because of the smaller blend zone of the tissue-saving algorithm. Contrast sensitivity and patient satisfaction were comparable between the 2 methods.
Hashemi
Hassan
H
Ophthalmology Department, Farabi Eye Hospital, Tehran Medical University, Tehran, Iran.
Nazari
Rahman
R
Amoozadeh
Javad
J
Beheshtnejad
Amir Houshang
AH
Jabbarvand
Mahmoud
M
Mohammadpour
Mehrdad
M
Hashemian
Hesam
H
D000328:Adult; D000465:Algorithms; D015350:Contrast Sensitivity / Q000502:physiology*; D057108:Corneal Wavefront Aberration / Q000209:etiology*; D005260:Female; D006801:Humans; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D009216:Myopia / Q000601:surgery*; D017060:Patient Satisfaction; D018903:Photorefractive Keratectomy / Q000379:methods*; D011183:Postoperative Complications; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult