effect of photorefractive keratectomy on corneal biomechanics
نویسندگان
چکیده
purpose: to assess alterations in parameters measured by the ocular response analyzer (ora) after photorefractive keratectomy (prk) with or without 0.02% mitomycin c (mmc) in myopic eyes. methods: in 33 right eyes of 33 patients, iop was determined using the goldmann applanation tonometry (gat) before and 3 months after prk. corneal hysteresis (ch), corneal resistance factor (crf), goldmann-correlated iop (iopg), and cornea-compensated iop (iopcc) were also measured. pre- and postoperative values were compared and the effect of ablation depth, optical zone, and duration of mmc application on changes in corneal biomechanics was examined. results: mean ablation depth was 56.6±20.8 microns. postoperatively, there was a significant reduction in corneal biomechanical properties and iop readings by the gat and ora. ablation depth was significantly associated with percentage change in ch (p=0.021), crf (p=0.001), and iop gat (p<0.001). however, the size of optical zone and duration of mmc application was not correlated with these parameters. the percentage of change in iop gat and in iopg but not in iopcc was significantly associated with percentage of change in ch and in crf. conclusion: prk reduces corneal biomechanical properties which is proportional to the amount of ablation. however, other variables including optical zone and duration of mmc application have no effect. iopcc appeared to be less dependent on alterations in corneal properties than iopg and iop gat.
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عنوان ژورنال:
بیناجلد ۱۸، شماره ۱، صفحات ۲۳-۲۹
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