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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cataract surgery is known to induce refractive and corneal astigmatism, but little is known regarding the specific corneal topographic alterations produced by this surgery. We evaluated the corneal topographic effects of extracapsular cataract extraction (ECCE) performed with an 8- to 11-mm posterior limbal incision closed with interrupted sutures and subsequent selective suture removal. Corneal topography was analyzed in 15 eyes with the TMS-1 videokeratoscope preoperatively, before selective suture removal 4-6 weeks after surgery, 2-5 weeks after selective removal of sutures, and at 5 1/2-8 months after surgery. The Surface Regularity Index was significantly increased before suture removal and after suture removal but returned to normal at the final examination. The Irregular Astigmatism Index remained significantly increased at all examinations after surgery. Corneal asymmetry (Surface Asymmetry Index) continued to be significantly increased compared with the preoperative examination after suture removal and at 6 months after surgery. The standard deviation of powers (SDP) was significantly elevated before and immediately after suture removal, but was not significantly different at 6 months. Mean corneal astigmatism remained significantly increased (0.80 +/- 0.11 preoperatively, 1.39 +/- 0.24 at maximum follow-up, p = 0.04). Significant changes in corneal topography occurred in each patient between suture removal and final examinations. A few patients developed against-the-rule astigmatism ranging from 0.6 to 2.2 diopters. ECCE significantly altered corneal tomography compared with the preoperative contour in all patients. In those patients in whom surgically induced nonspherical and noncylindrical distortions occur (radially asymmetrical power distribution, lack of central corneal smoothness), corneal topography may provide information that is useful for management.
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PMID:Prospective study of corneal topographic changes produced by extracapsular cataract surgery. 892 69

The purpose of this study was to evaluate the corneal irregular astigmatism following photorefractive keratectomy (PRK) for myopia. The corneal topography of 30 eyes of 26 patients was measured with the TMS-1 videokeratoscope before and 1 month after PRK. Axial dioptric data were decomposed into four components; A0 (Sphericity), C1 x 2 (Asymmetry), C2 x 2 (Regular astigmatism), and C3 (higher-order irregularity) for the central 3 and 6 mm zone by Fourier series harmonic analysis. Post-operative topographies were divided into those with an irregular and those with a homogeneous pattern, and the Fourier components were compared. In the 6 mm zone, A0 was significantly decreased (P < 0.001), and C1 x 2, C2 x 2, and C3 were significantly increased (P = 0.001, 0.005, 0.002, respectively). In the 3 mm zone, A0 decreased (P < 0.001) and C1 x 2 increased (P < 0.001) significantly. C1 x 2 was correlated with the post-operative corrected visual acuity (P < 0.001, r = 0.647). The irregular pattern group had a larger C1 x 2 component (P < 0.001). The treatment displacement was not correlated with any component. In conclusion, irregular topography due to intraoperative drift or asymmetrical wound healing may play a more important role in the post-operative corneal optical property than mild treatment displacement.
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PMID:Fourier analysis of corneal astigmatic changes following photorefractive keratectomy. 1275 57