Intraocular lens calculations status after corneal refractive surgery

Current Opinion in Ophthalmology

Volumn 11, Issue 1, 2000, Pages 35-46

  Seitz, Berthold ^a   Langenbucher, Achim ^a  

^a UNIVERSITY HOSPITAL ERLANGEN   (Germany)

Author keywords

[No Author keywords available]

Indexed keywords

ARTICLE; CATARACT EXTRACTION; CONTROLLED STUDY; CORNEA SURGERY; DEVICE; HUMAN; KERATECTOMY; KERATOMETRY; KERATOMILEUSIS; LENS IMPLANTATION; LENS POWER; MATHEMATICAL COMPUTING; PRIORITY JOURNAL; RADIAL KERATOTOMY; REFRACTION ERROR;

CORNEA; HUMANS; KERATECTOMY, PHOTOREFRACTIVE, EXCIMER LASER; KERATOMILEUSIS, LASER IN SITU; KERATOTOMY, RADIAL; LENS IMPLANTATION, INTRAOCULAR; LENSES, INTRAOCULAR; MATHEMATICS; OPTICS; REFRACTIVE ERRORS; REOPERATION; VISUAL ACUITY;

EID: 0033966206     PISSN: 10408738     EISSN: None     Source Type: Journal    
DOI: 10.1097/00055735-200002000-00006     Document Type: Article

References (61)

1. 1 Markovits AS: Extracapsular cataract extraction with posterior chamber intraocular lens implantation in a postradial keratotomy patient. Arch Ophthalmol 1986; 104: 329-331.
2. 2 Koch DD, Liu JF, Hyde LL, Rock RL, Emery JM: Refractive complications of cataract surgery after radial keratotomy. Am J Ophthalmol 1989, 108: 676-682.
3. 3 Celikkol L, Pavlopoulos G, Weinstein B, Celikkol G, Feldman S: Calculation of intraocular lens power after radial keratotomy with computerized videokeratography. Am J Ophthalmol 1995, 120:739-750.
4. 4 Lyle WA, Jin GJC: Intraocular lens power prediction in patients who undergo cataract surgery following previous radial keratotomy. Arch Ophthalmol 1997, 115:457-461.
5. 5 Lesher MP, Schumer DJ, Hunkeler JD, Durrie DS, McKee FE: Phacoemulsification with intraocular lens implantation after excimer laser photorefractive keratectomy: a case report. J Cataract Refract Surg 1994, 20(suppl):265-267.
6. 6 Kalski RS, Danjoux JP, Fraenkel GE, Lawless MA, Rogers C: Intraocular lens power calculation for cataract surgery after photorefractive keratectomy for high myopia. J Refract Surg 1997, 13:362-366.
7. 7 Loughnan M, Sutton GL, Fraenkel GE, Wolfe R, Barrett G: Clinical consultations: intraocular lens power calculation following corneal refractive surgery. Aust N Z J Ophthalmol 1998, 26:343-345. Based on a clinical scenario of cataract surgery after a -4.5-D PRK, suggestions are made by three authors about how to calculate the IOL power if full access to the patient's pre-PRK examination results was or was not available. Methods included refraction-derived keratometric values, rigid trial contact lenses, and intraoperative "optometry."
8. 8 McDonnell PJ: Can we avoid an epidemic of refractive "surprises" after cataract surgery [editorial]? Arch Ophthalmol 1997, 115:542-543.
9. 9 Bardocci A, Lofoco G: Corneal topography and postoperative refraction after cataract phacoemulsification following radial keratotomy. Ophthalmic Surg Lasers 1998, 30:155-159. Phacoemulsification and IOL implantation in a 55-year old patient after 8-cut RK elsewhere resulted in a prediction error of 2.5 D using the "effective refractive power" of the Holladay's Diagnostic Summary (EyeSys) in the SRK/T formula. After uneventful cataract surgery, corneal topography showed a significant initial flattening of approximately 2 D, which returned to preoperative corneal curvature after 23 weeks.
10. 10 Morris AHC, Whittaker KW, Morris RJ, Corbett MC: Errors in intraocular lens power calculation after photorefractive keratectomy. Eye 1998, 12:327-328. Phacoemulsification and IOL implantation in a 66-year old patient after -7.0 D PRK elsewhere resulted in a prediction error of 5.0 D using keratometric diopters as assessed by the Topcon OM-4 Ophthalmometer (Topcom; Paramus, NJ, USA) in the SRK II formula. Because of intolerable aniseikonia, IOL replacement became necessary, resulting in a final refractive error of +1-0.5 D. Retrospectively, the authors recommend to use the highest IOL power predicted by more than one third-generation formula based on refraction-derived keratometry or central corneal topography analysis. Keratometry readings should be routinely obtained before PRK and be made available for subsequent cataract extraction and IOL implantation.
11. 11 Roberts C: Corneal topography: a review of terms and concepts. J Cataract Refract Surg 1996, 22:624-629.
12. 12 Roberts C: Principles of corneal topography. In Principles and Practice of Refractive Surgery. Edited by Elander R, Rich LF, Robin JB. Philadelphia: WB Saunders, 1997:476-497.
13. 13 Holladay JT: Cataract surgery in patients with previous keratorefractive surgery (RK, PRK, and LASIK). Ophthalmic Pract 1997, 15:238-244.
14. 14 Manning CA, Kloess PM: Comparison of portable automated keratometry and manual keratometry for IOL calculation. J Cataract Refract Surg 1997, 23: 1213-1216.
15. 15 Wilson SE, Klyce SD: Quantitative descriptors of corneal topography: a clinical study. Arch Ophthalmol 1991, 109:349-353.
16. 16 Maeda N, Klyce SD, Smolek MK, McDonald MB: Disparity between keratometry-style readings and corneal power within the pupil after refractive surgery for myopia. Cornea 1997, 16:517-524.
17. 17 Holladay JT: Corneal topography using the Holladay Diagnostic Summary. J Cataract Refract Surg 1997, 13:209-221.
18. 18 Seitz B, Behrens A, Langenbucher A: Corneal topography. Curr Opin Ophthalmol 1997, 8:8-24.
19. 19 Seitz B, Langenbucher A, Nguyen NX, Kus MM, Küchle M. Underestimation of intraocular lens power for cataract surgery after myopic photorefractive keratectomy. Ophthalmology 1999, 106:693-702. Model calculations in 31 eyes after PRK for myopia (-1.5 to -8.0 D; mean, -5.4±1.9 D) revealed that pre-PRK and post-PRK, keratometric diopters as assessed by the Zeiss keratometer were significantly (≈ 1.0 D) smaller than keratometric diopters as assessed by TMS-1 topography analysis (P < 0.001 ). After PRK, mean measured keratometric diopters were significantly greater (absolute difference, 0.4 D) than respective calculated values considering the preoperative to postoperative change of the anterior corneal surface (P < 0.001), which was significantly greater (absolute difference, 0.6-0.7 D) than calculated keratometric diopters considering the preoperative to postoperative SEQ change at the corneal plane (P < 0.001). The smallest keratometric diopters (absolute difference, 0.3-0.4 D) were achieved considering the preoperative to postoperative SEQ change at the spectacle plane (P < 0.001). For the Haigis and SRK/T formulas, IOL power values using keratometer readings were significantly higher (> 1 D) than IOL power values using topography analysis readings (P < 0.001). On average, the theoretically induced ametropia after fictitious IOL implantation may reach +1.4 D (maximum, +3.1 D). Overestimation of keratometric diopters and underestimation of IOL power correlated significantly with the difference between the preoperative and postoperative SEQ (P = 0.001) and with the intended depth of PRK ablation (P = 0.004).
20. 20 Gelender N, Gelber EC: Cataract following radial keratotomy. Arch Ophthalmol 1983, 101:1229-1231.
21. 21 Casebeer JC, Shapiro DR, Ingram RW, Genstler A: Phacoemulsification after T-hex keratotomy. J Cataract Refract Surg 1993, 19:778-779.
22. 22 Siganos DS, Pallikaris IG, Lambropoulos JE, Koufala CJ: Keratometric readings after photorefractive keratectomy are unreliable for calculating IOL power. J Refract Surg 1996, 12:278-279.
23. 23 Speicher L, Göttinger W: Intraocular lens power calculation after decentered photorefractive keratectomy. J Cataract Refract Surg 1999, 25:140-143. Phacoemulsification and IOL implantation in a 59-year old patient after decentered -18.0-D PRK resulted in a refraction of +4.0 D using automated keratometry and the SRK II formula. Because of intolerable polyopia and aniseikonia, IOL replacement became necessary, resulting in a final refractive error of +0.75 D. Retrospectively, the authors recommend to use refraction-derived keratometric diopters on the corneal plane in a third-generation formula but not the SRK II formula. The authors emphasize that post-PRK refraction must be determined before a myopic shift caused by a nuclear cataract develops.
24. 24 Amm M, Halberstadt M: IOL power calculation after decentered laser in situ keratomileusis. Ophthalmologe 1999, 96(suppl 1):37.
25. 25 Seiler T, McDonnell PJ: Excimer laser photorefractive keratectomy. Surv Ophthalmol 1995, 40:89-118.
26. 26 Wilson SE, Klyce SD, McDonald MB, Liu JC, Kaufman HE: Changes in corneal topography after excimer laser photorefractive keratectomy for myopia. Ophthalmology 1991, 98:1338-1347.
27. 27 Waring GO III, Lynn MJ, McDonnell PJ, and the PERK Study Group: Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study 10 years after surgery. Arch Ophthalmol 1994, 112:1298-1308.
28. 28 Hanna KD, Jouve FE, Waring GO III: Preliminary computer simulation of the effects of radial keratotomy. Arch Ophthalmol 1989, 107:911-918.
29. 29 Sawusch MR, McDonnell PJ: Computer modeling of wound gape following radial keratotomy. Refract Corneal Surg 1992, 8:143-145.
30. 30 Buzard KA: Introduction to biomechanics of the cornea. Refract Corneal Surg 1992, 8:127-138.
31. 31 Olsen T: On the calculation of power from curvature of the cornea. Br J Ophthalmol 1986, 70:152-154.
32. 32 Mandel RB: Corneal power correction factor for photorefractive keratectomy. J Refract Corneal Surg 1994, 10:125-128.
33. 33 Gobbi PG, Carones F, Brancato R: Keratometric index, videokeratography, and refractive surgery. J Cataract Refract Surg 1998, 24:202-211. Using the keratometric index of refraction of 1.3375 is validated for estimating optical power differences of untreated corneas or after incisional keratotomy. It is not accurate in assigning absolute values of dioptric power, where the value 1.3315 is more appropriate. For PRK the proper stromal index of refraction, 1.376, must be used for ablation calculations and dioptric change estimates. The authors conclude that videokeratographic instruments should include three distinct values of refractive index (1.3375, 1.376, and 1.3315) for an accurate and complete characterization of dioptric power maps. In cataract surgery, corrections must be introduced in the calculation of IOL power for patients who have previously had PRK.
34. 34 Alimisi S, Miltsakakis D, Klyce S: Corneal topography for intraocular lens power calculations. J Refract Surg 1996, 12(suppl):309-311.
35. 35 Celikkol L, Ahn D, Celikkol G, Feldman ST: Calculating intraocular lens power in eyes with keratoconus using videokeratography. J Cataract Refract Surg 1996, 22:497-500.
36. 36 Cuaycong MJ, Gay CA, Emery J, Haft EA, Koch DD: Comparison of the accuracy of computerized videokeratography and keratometry for use in intraocular lens power calculation. J Cataract Refract Surg 1993, 19(suppl):178-181.
37. 37 Husain SE, Kohnen T, Maturi R, Er H, Koch DD: Computerized videokeratography and keratometry in determining intraocular lens calculations. J Cataract Refract Surg 1996, 22:362-366.
38. 38 Hannush SB, Crawford SL, Waring GO III, Gemmill MC, Lann MJ, Nizam A: Accuracy and precision of keratometry, photokeratoscopy, and corneal modeling on calibrated steel balls. Arch Ophthalmol 1989, 107:1235-1239.
39. 39 Seitz B, Langenbucher A, Kus MM, Küchle M, Naumann GOH: Nonmechanical corneal trephination with the excimer laser improves outcome after penetrating keratoplasty. Ophthalmology 1999, 106:1156-1165. "All-suture-out" astigmatism and best-corrected visual acuity after penetrating keratoplasty were significantly more favorable using the excimer laser for nonmechanical trephination in contrast to the motor trephine. "Central power" and astigmatism as assessed by TMS-1 topography analysis were significantly higher (average, 1 D) than the respective values as assessed by standard Zeiss keratometry.
40. 40 Karabatsas CH, Cook SD, Powell K, Sparrow JM: Comparison of keratometry and videokeratography after penetrating keratoplasty. J Refract Surg 1998, 14:420-426.
41. 41 Hugger P, Kohnen T, Koch DD: Assessment of refractive change following photorefractive keratectomy: keratometry versus computerized videokeratography. Ophthalmologe 1997, 94:699-702.
42. 42 Holladay JT: Intraocular lens power calculations for cataract and refractive surgery. In Refractive Surgery: Current Techniques and Management. Edited by Serdarevic ON. New York: Igaku-Shoin; 1997:183-193.
43. 43 Retzlaff JA, Sanders DR, Kraff MC: Development of the SRK/T intraocular lens implant power calculation formula. J Cataract Refract Surg 1990, 16: 333-340, 528.
44. 44 Sanders DR, Retzlaff JA, Kraff MC, Gimbel HV, Raanan MG: Comparison of the SRK/T formula and other theoretical and regression formulas. J Cataract Refract Surg 1990, 16:341-436.
45. 45 Haigis W: IOL Calculation According to HAIGIS [on-line]. Available: http://www.augenklinik.uni-wuerzburg.de/uslab/ioltxt/haid.htm.
46. 46 Holladay JT, Prager TC, Chandler TY, Musgrove KH, Lewis JW, Ruiz RS: A three-part system for refining intraocular lens power calculations. J Cataract Refract Surg 1988, 14:17-24.
47. 47 Hoffer KJ: The Hoffer Q formula: a comparison of theoretic and regression formulas. J Cataract Refract Surg 1993, 19:700-712.
48. 48 Olsen T, Thim K, Corydon L: Accuracy of newer generation intraocular lens power calculation formulas in long and short eyes. J Cataract Refract Surg 1991, 17:187-193.
49. 49 Holladay JT, Gills JP, Leidlein J, Cherchio M: Achieving emmetropia in extremely short eyes with two piggyback posterior chamber intraocular lenses. Ophthalmology 1996, 103:1118-1123.
50. 50 Kohnen T, Koch MJ: Refractive aspects of cataract surgery. Curr Opin Ophthalmol 1998, 9:55-59.
51. 51 Olsen T: Sources of error in intraocular lens power calculation. J Cataract Refract Surg 1992, 18:125-129.
52. 52 McEwans JR, Massengill RK, Friedel SD: Effect of keratometry and axial length measurement errors on primary implant power calculations. J Cataract Refract Surg 1990, 16:61-70.
53. 53 Hoffmann PC, Hütz WW, Eckhardt HB: Importance of IOL calculation formulas for postoperative refraction after cataract surgery. Klin Monatsbl Augenheilkd 1997, 211:168-177.
54. 54 Seitz B, Langenbucher A, Hofmann B, Behrens A, Kus MM: Refractive power of the human posterior corneal surface in vivo in relation to gender and age. Ophthalmologe 1998, 95(suppl 1):50.
55. 55 Guyton DL: Consultations in refractive surgery. Refract Corneal Surg 1989, 5:203.
56. 56 Holladay JT: Consultations in refractive surgery. Refract Corneal Surg 1989, 5:203.
57. 57 Hoffer KJ: Intraocular lens power calculation for eyes after refractive keratotomy. J Refract Surg 1995, 11:490-493.
58. 58 Seitz B, Langenbucher A, Nguyen NX, Kus MM, Küchle M: Fehlbestimmung von Hornhautbrechkraft und Kunstlinsenstärke bei Kataraktoperation nach PRK [in German]. In Kongreβ der Deutschsprachigen Gesellschaft für Intraokularlinsenimplantation und refraktive Chirurgie. Edited by Duncker G, et al. Berlin: Springer; 1998:447-455.
59. 59 Happe W, Wiechens B, Haigis W, Behrendt S, Duncker G: Intraocular lens power calculation using intraoperative retinoscopy. Klin Monatsbl Augenheilkd 1997, 210:207-212.
60. 60 Basuk WL, Zisman M, Waring GO III, Wilson LA, Binder PS, Thompson KP, et al.: Complications of hexagonal keratotomy. Am J Ophthalmol 1994, 117: 37-49.
61. 61 Langenbucher A, Seitz B, Kus MM, Nguyen NX, Küchle M: Berechnung der Kunstlinsenstärke nach photorefraktiver Keratektomie [in German]. In Kongreβ der Deutschsprachigen Gesellschaft für Intraokularlinsenimplantation und refraktive Chirurgie. Edited by Duncker G, et al. Berlin: Springer; 1998: 441-446.