The applicability of correction factor for corneal thickness on non-contact tonometer measured intraocular pressure in LASIK treated eyes

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• 作者：Jitendra Jethani^a ; ^b ; Paaraj Dave^a ; ^{paaraj@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; Monica Jethani^b ; Yogesh Desai^b ; Purvi Patel^b
• 关键词：NCT ; CCT ; LASIK ; Intraocular pressure ; Correction
• 刊名：Saudi Journal of Ophthalmology
• 出版年：2016
• 出版时间：January-March 2016
• 年：2016
• 卷：30
• 期：1
• 页码：25-28
• 全文大小：444 K

文摘

To determine the applicability of central corneal thickness (CCT) based correction factor for non-contact tonometer (NCT) measured intraocular pressure (IOP) readings.

d="absSec_2">Method

d="sp0010">A prospective, non-randomized study involved 346 eyes of 173 consecutive patients with age ⩾21 years undergoing laser-assisted in situ keratomileusis (LASIK) for myopia and/or myopic astigmatism. The CCT and IOP were measured before and after the LASIK procedure. The IOP pre and post-LASIK was compared after applying the correction factor for CCT. Patients not completing the 3 month postoperative follow-up were excluded.

d="absSec_3">Results

d="sp0015">The median spherical equivalent before undergoing LASIK was −4.25D (inter-quartile range, −3.25D). The mean preoperative CCT was 536.82 ± 33.71 μm which reduced to 477.55 ± 39.3 μm (p < 0.01) post-LASIK. The mean IOP reduced from a preoperative value of 14.6 ± 2.32 mmHg to 10.64 ± 2.45 mmHg postoperatively (p < 0.01). On applying correction for the corneal thickness, the pre and postoperative IOP was 15.14 ± 2.8 mmHg and 15.37 ± 2.65 mmHg (p = 0.06) respectively with a strong positive correlation (r = 0.7, p < 0.01). Three hundred eyes (86.7%) had an absolute difference in IOP of less than 3.0 mmHg post-CCT correction which is within the retest variability of NCT. Only 46 eyes (13.3%) had an absolute difference of more than 3.0 mmHg.

d="absSec_4">Conclusion

d="sp0020">The modified Ehler’s correction algorithm used in this study can be effectively applied in the normal IOP range in a majority of patients.