Publications (8)24.13 Total impact
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Article: Astigmatic neutrality in 1.9-mm coaxial microincision phacoemulsification.
Journal of refractive surgery (Thorofare, N.J.: 1995) 07/2012; 28(7):451-2. · 2.54 Impact Factor -
Article: Toric intraocular lens calculations-reply.
Archives of ophthalmology 07/2012; 130(7):947-9. · 3.86 Impact Factor -
Article: Toric intraocular lens outcome using the manufacturer's prediction of corneal plane equivalent intraocular lens cylinder power.
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ABSTRACT: To describe the refractive outcome of toric intraocular lens (IOL) implantation by comparing the postoperative refractive astigmatism with the preoperative keratometric astigmatism target. In a university department of a publicly funded hospital, 38 eyes of 29 patients underwent routine cataract surgery with insertion of a toric implant (SN60TT AcrySof Toric). Surgically induced astigmatism was derived using vector analysis of refractive outcome vs predicted postoperative keratometric astigmatism and compared with the targeted induced astigmatism. Postoperative remaining refractive astigmatism of 0.97 diopters (D) was achieved vs a target of 0.61 D. A mean (SD) surgically induced astigmatism value of 1.78 (0.89) D was derived compared with a mean (SD) targeted induced astigmatism value of 1.58 (0.47) D (calculated by the manufacturer's online calculator, which predicts IOL corneal plane equivalent cylinder power and postoperative keratometric cylinder). Toric IOLs are a safe, predictable method of astigmatic correction. However, some remaining astigmatism is commonly present owing to the necessary nonzero astigmatic targets imposed by the steps between IOL cylinder powers, variability of axis, and power effects of surgical incisions as well as by underestimation of the corneal plane cylinder power of the IOLs by the manufacturer.Archives of ophthalmology 08/2011; 129(8):1004-8. · 3.86 Impact Factor -
Article: Outcome of toric intraocular lens implantation after adjusting for anterior chamber depth and intraocular lens sphere equivalent power effects.
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ABSTRACT: To describe the refractive outcome of toric intraocular lens (IOL) implantation by taking into account the effect on astigmatic outcome of the anterior chamber depth and the sphere power of the IOL, and to examine whether the predictability of the toric effect can be improved. In a university department in a publicly funded hospital, 38 eyes of 29 patients underwent routine cataract surgery with insertion of a toric implant (SN60TT AcrySof Toric). The corneal plane effective cylinder power of the IOL was calculated, including the effect on this value of the anterior chamber depth and pachymetry and of the sphere power of the IOL. The mean (SD) corneal plane equivalent cylinder power of the IOL predicted preoperatively by the manufacturer as 1.58 (0.47) diopters (D) vs 2.02 (0.64) D by us (calculated using predicted postoperative anterior chamber depth and IOL sphere values). The mean (SD) measured postoperative value was 1.78 (0.89) D, which was better predicted by us. The manufacturer currently appears to underestimate the corneal plane effective cylinder power of its toric IOLs. Improved outcome could be achieved by estimating the effective corneal plane cylinder power of the IOL, as altered by the anterior chamber depth and pachymetry and by the IOL sphere power, but this is currently not addressed by the manufacturer.Archives of ophthalmology 08/2011; 129(8):998-1003. · 3.86 Impact Factor -
Article: Variation in surgically induced astigmatism estimation due to test-to-test variations in keratometry.
Journal of cataract and refractive surgery 10/2010; 36(10):1792-3. · 2.75 Impact Factor -
Article: Corneal limbal marking in the treatment of myopic astigmatism with the excimer laser.
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ABSTRACT: To determine whether preoperative marking of the limbal cornea improves treatment of myopic astigmatism with the excimer laser. Retrospective study on 108 eyes with myopic astigmatism that underwent LASIK or laser epithelial keratomileusis (LASEK) with the Technolas 217 (Bausch & Lomb) excimer laser. Preoperative limbal marking was performed in 47 eyes (marked group). The 12-month results were used for refractive and visual analysis. The achieved cylinder reduction, spherical reduction, and refractive predictability were similar for the marked and unmarked groups in the overall study collective, in the LASIK and LASEK subgroup analysis, and in a higher astigmatism (> 1.25 diopters) subgroup analysis. Limbal marking showed no influence on the refractive results, and vector analysis showed no significant difference in angle of error among groups. Corneal limbal marking failed to improve the refractive outcome in LASIK and LASEK for myopic astigmatism.Journal of refractive surgery (Thorofare, N.J.: 1995) 10/2009; 26(7):505-11. · 2.54 Impact Factor -
Article: Astigmatic neutrality in biaxial microincision cataract surgery.
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ABSTRACT: To assess the astigmatic effect of biaxial microincision cataract surgery (MICS) with insertion of an UltraChoice 1.0 Rollable Thinlens intraocular lens (IOL) in a sufficiently powered controlled study. Queen Elizabeth Hospital, South Australian Institute of Ophthalmology, University of Adelaide, Adelaide, Australia. Consecutive patients having biaxial MICS were evaluated prospectively. Keratometry was performed preoperatively and postoperatively. Vector analysis of the alteration in the keratometric cylinder was compared with that in control eyes not having surgery but having keratometry over a similar time frame. There were 76 eyes in the surgical group and 74 in the control group. The right-hand incision used for IOL insertion had a mean external opening width of 2.00 mm and a mean internal width of 1.89 mm. The left-hand incision measured a mean of 1.49 mm and 1.46 mm, respectively. There was no statistically significant difference between the surgical group and the routine variability in keratometry in the untreated control group in surgically induced astigmatism (surgical group, 0.57 diopter [D] +/- 0.05 [SEM]; control group, 0.54 +/- 0.06 D; P =.660) or the degree of mean calculated flattening effect at the right-hand incision (0.01 +/- 0.06 D and -0.05 +/- 0.05 D, respectively; P = .405) or at the left-hand incision (-0.06 +/- 0.05 D and 0.03 +/- 0.06 D, respectively; P = .283). Biaxial MICS with insertion of IOL through a temporal incision of 2.0 mm offers prospects of astigmatic neutrality in cataract surgery.Journal of cataract and refractive surgery 10/2009; 35(9):1555-62. · 2.75 Impact Factor -
Article: Astigmatic change in biaxial microincisional cataract surgery with enlargement of one incision: a prospective controlled study.
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ABSTRACT: To investigate the astigmatic changes induced by biaxial microincisional cataract surgery with enlargement of one incision to accommodate a foldable standard lens. In a prospective controlled trial one eye each of 50 patients was evaluated. Two temporal microincisions were applied and the right-hand incision was enlarged to 2.8 mm to allow for the insertion of the lens. Based on preoperative and postoperative keratometry readings, vector analysis was performed to calculate the surgically induced astigmatism (SIA) and the flattening effect of each of the two incisions at their meridia. To assess the degree of measurement error, a non-surgical control group underwent keratometry over the same time frame and vector analysis was used to calculate the same indices based on the variation in the keratometry readings. Six weeks postoperatively, mean SIA was 0.66 +/- 0.08 D in the study group and 0.51 +/- 0.05 D in the non-surgical control group (P = 0.041). At the right-hand incision, a flattening of 0.34 +/- 0.09 D was measured in the study group as opposed to a steepening of 0.03 +/- 0.06 D in the control group (P < 0.001). At the smaller left-hand incision, steepening effects of 0.28 +/- 0.08 and 0.05 +/- 0.06 D occurred, respectively (P = 0.011). Biaxial microincisional cataract surgery with enlargement of one incision to 2.8 mm is not astigmatically neutral, demonstrating a statistically significantly larger SIA than that attributable to measurement error.Clinical and Experimental Ophthalmology 05/2009; 37(3):254-61. · 1.98 Impact Factor
Top co-authors
Top Journals
Institutions
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2011
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University of Adelaide
- South Australian Institute of Ophthalmology
Adelaide, South Australia, Australia -
The Queen Elizabeth Hospital
- Department of Ophthalmology
Adelaide, South Australia, Australia
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