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Value of posterior keratometry in the assessment of surgically induced astigmatic change in cataract surgery
Author(s) -
Klijn Stijn,
Sommen Charlotte M.,
Sicam Victor Arni D. P.,
Reus Nicolaas J.
Publication year - 2016
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/aos.13003
Subject(s) - keratometer , meridian (astronomy) , scheimpflug principle , medicine , ophthalmology , cataract surgery , corneal topography , cornea , surgery , physics , astronomy
Purpose To investigate the value of posterior keratometry in the assessment of surgically induced astigmatic change (AC) in cataract surgery, with particular emphasis on the influence of test–retest variability. Methods Seventy‐seven eyes of 77 cataract patients scheduled for routine cataract surgery were enrolled. All patients received a 2.2‐mm self‐sealing scleral incision ( n = 24), single‐plane clear corneal incision ( SPCCI ; n = 29) or biplanar clear corneal incision ( BPCCI ; n = 24). Measurements of anterior and posterior corneal astigmatism were performed with a rotating Scheimpflug camera (Pentacam HR ) preoperatively and postoperatively. Two repeated readings were taken preoperatively to assess the role of the test–retest effect. Astigmatic change (AC) was analysed according to the polar value method. Results On the anterior corneal surface, SPCCI s and BPCCI s caused a statistically significant mean flattening of the incisional meridian of 0.37 and 0.27 dioptres (D), respectively. Scleral incisions on average did not cause AC, although steepening, flattening or torque beyond the test–retest effect was observed in individual cases. On the posterior surface, mean power changes in the incisional meridian were below 0.1 D for all incisions, and these changes were of the same order of magnitude as the test–retest effect. Conclusion Surgically induced AC of the posterior corneal surface after cataract surgery is of negligible clinical relevance. Moreover, it is of the same order of magnitude as the test–retest variability of the measurement device and therefore cannot (yet) be reliably assessed.