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A Study of Optical Zone Size and Incision Redeepening in Experimental Radial Keratotomy

A Study of Optical Zone Size and Incision Redeepening in Experimental Radial Keratotomy Abstract • The effects of optical clear zone size and incision redeepening following four-and eight-incision radial keratotomy were studied in a series of human cadaver eyes. Keratometry was measured with both the Terry keratometer and corneascope photographs. After eight incisions, induced corneal flattening for each clear zone (Terry keratometry readings) was 3.0 mm, 9.06 diopters; 4.0 mm, 6.44 D; 5.0 mm, 5.23 D; and 6.0 mm, 2.29 D. Differences were statistically significant, except for the 4.0-mm and 5.0-mm zones. Induced corneal flattening following eight incisions (corneoscopy) was 3.0 mm, 9.83 D; 4.0 mm, 8.87 D; 5.0 mm, 6.04 D; and 6.0 mm, 2.59 D. Differences were statistically significant, except for the 3.0-mm and 4.0-mm zones. Peripheral redeepening of the incisions did not significantly increase the amount of corneal flattening for any optical zone, as measured by the Terry keratometer. However, the 3.0-mm optical zone flattened an additional 1.23 D after the redeepening incisions, as measured by corneoscopy. The redeepening incisions were complicated by perforations in 38% of the eyes. Titrating the effect of radial keratotomy by varying the size of the optical zone appears to be valid, but the value of peripheral redeepening in the acute laboratory situation is not supported by these data. References 1. Salz J, Lee J, Steel D, et al: Radial keratotomy in fresh human cadaver eyes . Ophthalmology 1981;88:742-746.Crossref 2. Salz JJ, Lee T, Jester J, et al: Analysis of incision depth following experimental radial keratotomy . Ophthalmology 1983;90:655-659.Crossref 3. Salz J: Keratometric results of radial keratotomy on human cadaver eyes , in Schachar R (ed): Refractive Modulation of the Cornea . Denison, Tex, LAL Publishing, 1981, pp 175-177. 4. Jester J, Venet T, Lee J, et al: A statistical analysis of radial keratotomy in human cadaver eyes . Am J Ophthalmol 1981;92:172-177. 5. Fyodorov S, Durnev V: Operation of dosaged dissection of corneal circular ligament in cases of myopia of mild degree . Ann Ophthalmol 1979; 11:1855-1890. 6. Hoffer K, Darin J, Pettit T, et al: Three years experience with radial keratotomy: The UCLA study . Ophthalmology 1983;90:627-636.Crossref 7. Arrowsmith R, Sanders D, Marks R: Visual, refractive, and keratometric results of radial keratotomy . Arch Ophthalmol 1983;101:873-881.Crossref 8. Kremer F, Marks R: Radial keratotomy: Prospective evaluation of safety and efficacy . Ophthalmol Surg 1983;14:925-930. 9. Dietz M, Sanders D, Marks R: Radial keratotomy: An overview of the Kansas City study . Ophthalmology 1984;91:467-478.Crossref 10. Henslee S, Rowsey J: New corneal shapes in kerato-refractive surgery . Ophthalmology 1983;90:245-250.Crossref 11. Rowsey J, Isaac MS: Corneoscopy in kerato-refractive surgery . Cornea 1983;2:133-142.Crossref 12. Rowsey JJ, Balyeat H, Rabinovitch B, et al: Predicting the results of radial keratotomy . Ophthalmology 1983;90:642-654.Crossref http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Archives of Ophthalmology American Medical Association

A Study of Optical Zone Size and Incision Redeepening in Experimental Radial Keratotomy

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Publisher
American Medical Association
Copyright
Copyright © 1985 American Medical Association. All Rights Reserved.
ISSN
0003-9950
eISSN
1538-3687
DOI
10.1001/archopht.1985.01050040132036
Publisher site
See Article on Publisher Site

Abstract

Abstract • The effects of optical clear zone size and incision redeepening following four-and eight-incision radial keratotomy were studied in a series of human cadaver eyes. Keratometry was measured with both the Terry keratometer and corneascope photographs. After eight incisions, induced corneal flattening for each clear zone (Terry keratometry readings) was 3.0 mm, 9.06 diopters; 4.0 mm, 6.44 D; 5.0 mm, 5.23 D; and 6.0 mm, 2.29 D. Differences were statistically significant, except for the 4.0-mm and 5.0-mm zones. Induced corneal flattening following eight incisions (corneoscopy) was 3.0 mm, 9.83 D; 4.0 mm, 8.87 D; 5.0 mm, 6.04 D; and 6.0 mm, 2.59 D. Differences were statistically significant, except for the 3.0-mm and 4.0-mm zones. Peripheral redeepening of the incisions did not significantly increase the amount of corneal flattening for any optical zone, as measured by the Terry keratometer. However, the 3.0-mm optical zone flattened an additional 1.23 D after the redeepening incisions, as measured by corneoscopy. The redeepening incisions were complicated by perforations in 38% of the eyes. Titrating the effect of radial keratotomy by varying the size of the optical zone appears to be valid, but the value of peripheral redeepening in the acute laboratory situation is not supported by these data. References 1. Salz J, Lee J, Steel D, et al: Radial keratotomy in fresh human cadaver eyes . Ophthalmology 1981;88:742-746.Crossref 2. Salz JJ, Lee T, Jester J, et al: Analysis of incision depth following experimental radial keratotomy . Ophthalmology 1983;90:655-659.Crossref 3. Salz J: Keratometric results of radial keratotomy on human cadaver eyes , in Schachar R (ed): Refractive Modulation of the Cornea . Denison, Tex, LAL Publishing, 1981, pp 175-177. 4. Jester J, Venet T, Lee J, et al: A statistical analysis of radial keratotomy in human cadaver eyes . Am J Ophthalmol 1981;92:172-177. 5. Fyodorov S, Durnev V: Operation of dosaged dissection of corneal circular ligament in cases of myopia of mild degree . Ann Ophthalmol 1979; 11:1855-1890. 6. Hoffer K, Darin J, Pettit T, et al: Three years experience with radial keratotomy: The UCLA study . Ophthalmology 1983;90:627-636.Crossref 7. Arrowsmith R, Sanders D, Marks R: Visual, refractive, and keratometric results of radial keratotomy . Arch Ophthalmol 1983;101:873-881.Crossref 8. Kremer F, Marks R: Radial keratotomy: Prospective evaluation of safety and efficacy . Ophthalmol Surg 1983;14:925-930. 9. Dietz M, Sanders D, Marks R: Radial keratotomy: An overview of the Kansas City study . Ophthalmology 1984;91:467-478.Crossref 10. Henslee S, Rowsey J: New corneal shapes in kerato-refractive surgery . Ophthalmology 1983;90:245-250.Crossref 11. Rowsey J, Isaac MS: Corneoscopy in kerato-refractive surgery . Cornea 1983;2:133-142.Crossref 12. Rowsey JJ, Balyeat H, Rabinovitch B, et al: Predicting the results of radial keratotomy . Ophthalmology 1983;90:642-654.Crossref

Journal

Archives of OphthalmologyAmerican Medical Association

Published: Apr 1, 1985

References