DOI: https://doi.org/10.22141/2309-8147.4.2.2016.172810

AN EVALUATION OF UNEXPECTED REFRACTIVE OUTCOMES FOLLOWING TORIC IOL IMPLANTATION FOR ASTIGMATISM: A SECTOR SUBTRACTION GRAPHICAL METHOD FOR CALCULATING THE EFFECTIVE ASTIGMATIC CORRECTION

Sudi Patel, Larysa Tutchenko, Oleksiy Voytsekhivskyy

Abstract


Aim. To present and test a simple graphical procedure for determining the actual effective astigmatic correction applied after implanting toric intra-ocular lenses using the planned and residual astigmatic corrections.
Methods. Nineteen cases where a range of toric intra-ocular lenses were implanted were refracted by objective means one year post-op. Of the 19, 14 cases presented with residual astigmatism ≥0.25DC. Using the presented geometric expression, the actual effective astigmatic correction was calculated for each of the 14 cases.
Results. The pre-op planned astigmatic corrections ranged from –1.50DC to –7.50DC. The residual astigmatic values at one year did not exceed –1.75DC. Residual astigmatism resulted from a combination of IOL rotational misalignment (either clockwise or anti-clockwise) coupled with under or overcorrection. The mean (±s.d) rotational misalignment was 1.6° (±7.5°) ranging from 0 to 44°. A signifi cant association between the actual effective cylinder power (y1), planned cylinder power (x1) and sine of planned cylinder axis (x2) was found as follows , y1 = 0.807x1 + 0.199x2 – 0.372 (F= 25.43, r= 0.907, p<0.001, n=14, rpower= 0.899, ppower<0.001, raxis= –0.011, paxis= 0.97).
Conclusion. The simple graphical procedure identifi ed the root cause of unexpected residual refractive errors after toric IOL implantion. In general there was a tendency towards underdelivery of IOL power and axis misalignment. The procedure allows the cataract surgeon to quickly identify the root cause of unexpected post-op refractive error and assist in providing better management options to enhance patient satisfaction.


Keywords


toric IOL, planned and actual effective astigmatic correction, residual astigmatism

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References


Airy G. B. On a peculiar defect in the eye, and a mode of correcting it / G. B. Airy // Transactions of the Cambridge Phil Soc. – 1827. – Vol. 2. – P. 267–271.

Donders F. C. On anomalies of accommodation and refraction of the eye / F. C. Donders; [translated by WD Moore]. – London, 1864. – New Sydenham Society. – P. 501–511.

Borish I. M. Clinical refraction / I. M. Borish. – Vol. 1. – [3rd edition]. – Chicago: The Profession Press, 1975. – p. 123.

Morlet N. Astimatism and analysis of its surgical correction / N. Morlet, D. Minassian, J. Dart // Br J Ophthalmol. – 2001. – Vol. 85. – P. 1127–1138.

Raasch T. W. Repeatability of subjective refraction in the myopic and keratoconic subjects: results of vector analysis / T. W. Raasch, K.B. Schechtman, L. J. Davis [et al.] // Ophthalmic Physiol Opt. – 2001. – Vol. 21. – P. 376–383.

Jalie M. The principles of ophthalmic lenses / M. Jalie – [2nd edition]. – London: Association of Dispensing Opticians, 1972. – P. 277–278.

Thibos L. N. Power vectors: An application of Fourier analysis to the description and statistical analysis of refractive error / L. N. Thibos, W. Wheeler, D. Horner // Optom and Vis Sci. – 1997. – Vol. 4. – P. 367–375.

Duncombe K. O. A new and remarkably sensitive test for astigmatism / K. O. Duncombe // Br J Physiol Optics. – 1933. – Vol. 7. – P. 112–1128.

Linksz A. Determination of axis and amount of astigmatic error by rotation of trial cylinder / A. Linksz //Arch Ophthalmol. – 1942. – Vol. 28. – P. 632–651.

Fearn W. W. L. The effect of axis errors on prescription comfort / W. W. L. Fearn // Optician. – 1948. – Vol. 115. – P. 355–357.

Anderson F. R. To tilt or not to tilt- a controversy rehashed / F. R. Anderson // Surv Ophthalmol. – 1969. – Vol. 14. – P. 55–60.

Guyton D. L. Prescribing cylinders: the problem of distortion / D. L. Guyton // Surv Ophthalmol. – 1977. – Vol. 22. – P. 177–188.

Retzlaff J. Vector analysis of astigmatism / J. Retzlaff, P. Paden, L. Ferrell // J Cataract Refract Surg. – 1993. – Vol. 19. – P. 393–398.

Krall E. M. Vector analysis of astigmatism correction after toric intraocular lens implantation / E. M. Krall, E. M. Arlt, M. Hohensinn [et al.] // J Cataract Refract Surg. – 2015. – Vol. 41. – P. 790–799.

Bascaran L. Effi cacy and stability of AT TORBI 709 M toric IOL / L. Bascaran, J. Mendicute, B. Macias-Murelaga [et al.] // J Cataract Refract Surg. – 2013. – Vol. 39. – P. 194–199.

Hyon J. Y. Rotational stability of a single-piece hydrophobic acrylic intraocular lens during removal of ophthalmic viscosurgical devices / J. Y. Hyon, H. E. Yeo // Am J Ophthalmol. – 2010. – Vol. 149. – P. 253–257.

Chan C. C. Management of astigmatism: toric intraocular lenses / C. C. Chan, E. J. Holland // Int Ophthalmol Clin. – 2012. – Vol. 52. – P. 21–30.

Patel C. K. Post-opPost-operative intraocular lens rotation: a randomized comparison of plate and loop haptic implants / C. K. Patel, S. Ormonde, P. H. Rosen [et al.] // Ophthalmology. – 1999. – Vol. 106. – P. 2190–2195.

Prinz A. Rotational stability and posterior capsule opacifi cation of a plate-haptic and an open-loop-haptic intraocular lens / A. Prinz, T. Neumayer, W. Buehl [et al.] // J Cataract Refract Surg. – 2011. – Vol. 37. – P. 251–257.

Visser N. Accuracy of toric intraocular lens implantation in cataract and refractive surgery / N. Visser, T. T. Berendscho, N. J. Bauer [et al.] // J Cataract Refract Surg. – 2011. – Vol. 37. – P. 1394–1402.

Afsar A. J. A comparison of visual performance between a rigid PMMA and a foldable acrylic intraocular lens / A. J. Afsar, S. Patel, R. L. Woods, W. Wykes // Eye (Lond). – 1999. – Vol. 13. – P. 329–335.

Visser N. Toric intraocular lenses: historical overview, patient selection, IOL calculation, surgical techniques, clinical outcomes, and complications /N. Visser, N. J. Bauer, R. M. Nuijts // J Cataract Refract Surg. – 2013. – Vol. 39. – P. 624–637.

Carlos L. Rotational stability of the V4b implatable collamer lens / L. Carlos, J. F. Alfonso, L. Fernandez-Vega [et al.] // J Emmetropia. – 2015. – Vol. 6. – P. 7–12.

Holland E. The AcrySof toric intraocular lens in subjects with cataracts and corneal astigmatism; a randomized, subject-maskied, parallel-group, 1 year study / E. Holland, S. Lans, J. D. Horn [et al.] // Ophthalmology. – 2010. – Vol. 117. – P. 2104–2111.

Hoffmann P. C. Results of higher power toric intraocular lens implnation / P. C. Hoffmann, S. Aule, W. W. Hütz // J Cataract Refract Surg. – 2011. – Vol. 37. – P. 1411–1418.

Chua W. H. Matched comparison of rotational stability

of 1-piece acrylic and plate-haptic silicone toric intraocular lenses in Asian eyes / W. H. Chua, L. H. Yuen, J. Chua [et al.] // J Cataract Refract Surg. – 2012. – Vol. 38. – P. 620–624.

Sheppard A. L. Clinical outcomes aftter implnation of a new hydrophobic acrylic toric IOL during routine catarct surgery / A. L. Sheppard, J. S. Wolffsohn, U. Bhatt [et al.] // J Cataract Refract Surg. – 2013. – Vol. 39. – P. 41–47.

Scialdone A. Visual performance of two aspheric toric intraocular lenses: a comparative study / A. Scialdone, F. De Gaetano, G. Monaco // J Cataract Refract Surg. – 2013. – Vol. 39. – P. 906–914.

Bachernegg A. Rotational stability and visual outcome after implantation of a new toric intraocular lens for the correction of corneal astigmatism during cataract surgery / A. Bachernegg, T. Rückl, W. Riha [et al.] // J Cataract Refract Surg. – 2013. – Vol. 39. – P. 1390–1398.


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