Journal of Refractive Surgery

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Original Article 

Measure of Keratoconus Progression Using Orbscan II

Hyojin Kim, PhD; Choun-Ki Joo, MD, PhD

Abstract

PURPOSE

To observe the progression of keratoconus over 3 years using Orbscan II, and to estimate risk correlations with rapid progressive changes.

METHODS

Fifty-six eyes of 35 patients (mean age: 25.9±5.7 years, range: 18 to 35 years) with keratoconus were reviewed whose sex, age, visual acuity, refractive error, atopy, eye rubbing habits, family history of keratoconus, hard contact lens wear, intraocular pressure, keratometric reading, corneal shape, corneal thickness index, and corneal asphericity had been determined. The keratometric change over 3 years was evaluated using Orbscan II, with 6-month intervals between each examination. All patients selected had less than moderate keratoconus on initial examination.

RESULTS

The rate of keratometric change was 0.78±099 of keratometric change of 1.37±1.08 D/half-year, whereas the rate of change was 0.15±0.15 D/half-year in eyes exhibiting no apparent progression (P=.001). Logistic regression analysis showed that eye rubbing (odds ratio [OR] = 3.810; 95% confidence interval [CI] = 1.194-12.158) and inferior steepening compared to superior steepening (OR = 5.465; 95% CI = 1.667-17.857) were associated with progression after diagnosis (P<.05).

CONCLUSIONS

Careful attention must be paid to the presence of eye rubbing and corneal shape with inferior steepening at the time of diagnosis, as these factors may help in predicting the rapid progressive change in keratoconus. [J Refract Surg. 2008;24:600-605.]

ABOUT THE AUTHORS

From the Department of Visual Optics, Division of Health Science, Baekseok University (Kim), and the Department of Ophthalmology and Visual Science, College of Medicine, The Catholic University of Korea (Kim, Joo), Seoul, Korea.

The authors have no financial or proprietary interest in any of the materials presented herein.

Presented in part at the American Society of Cataract & Refractive Surgery meeting; April 16-20, 2005; Washington, DC.

The authors thank Lim Kooi Ling and John A. Vukich, MD, for critical reading and helpful discussions during this study.

Correspondence: Choun-Ki Joo, MD, PhD, Dept of Ophthalmology and Visual Science, Kangnam St Mary’s Hospital, College of Medicine, The Catholic University of Korea, # 505 Banpo-dong, Seocho-ku, Seoul, 137-040, Republic of Korea. Tel: 82 2 590 2615; Fax: 82 2 533 3801; E-mail: ckjoo@catholic.ac.kr

Received: August 11, 2005

Accepted: June 2, 2007

Posted online: November 15, 2007

Abstract

PURPOSE

To observe the progression of keratoconus over 3 years using Orbscan II, and to estimate risk correlations with rapid progressive changes.

METHODS

Fifty-six eyes of 35 patients (mean age: 25.9±5.7 years, range: 18 to 35 years) with keratoconus were reviewed whose sex, age, visual acuity, refractive error, atopy, eye rubbing habits, family history of keratoconus, hard contact lens wear, intraocular pressure, keratometric reading, corneal shape, corneal thickness index, and corneal asphericity had been determined. The keratometric change over 3 years was evaluated using Orbscan II, with 6-month intervals between each examination. All patients selected had less than moderate keratoconus on initial examination.

RESULTS

The rate of keratometric change was 0.78±099 of keratometric change of 1.37±1.08 D/half-year, whereas the rate of change was 0.15±0.15 D/half-year in eyes exhibiting no apparent progression (P=.001). Logistic regression analysis showed that eye rubbing (odds ratio [OR] = 3.810; 95% confidence interval [CI] = 1.194-12.158) and inferior steepening compared to superior steepening (OR = 5.465; 95% CI = 1.667-17.857) were associated with progression after diagnosis (P<.05).

CONCLUSIONS

Careful attention must be paid to the presence of eye rubbing and corneal shape with inferior steepening at the time of diagnosis, as these factors may help in predicting the rapid progressive change in keratoconus. [J Refract Surg. 2008;24:600-605.]

ABOUT THE AUTHORS

From the Department of Visual Optics, Division of Health Science, Baekseok University (Kim), and the Department of Ophthalmology and Visual Science, College of Medicine, The Catholic University of Korea (Kim, Joo), Seoul, Korea.

The authors have no financial or proprietary interest in any of the materials presented herein.

Presented in part at the American Society of Cataract & Refractive Surgery meeting; April 16-20, 2005; Washington, DC.

The authors thank Lim Kooi Ling and John A. Vukich, MD, for critical reading and helpful discussions during this study.

Correspondence: Choun-Ki Joo, MD, PhD, Dept of Ophthalmology and Visual Science, Kangnam St Mary’s Hospital, College of Medicine, The Catholic University of Korea, # 505 Banpo-dong, Seocho-ku, Seoul, 137-040, Republic of Korea. Tel: 82 2 590 2615; Fax: 82 2 533 3801; E-mail: ckjoo@catholic.ac.kr

Received: August 11, 2005

Accepted: June 2, 2007

Posted online: November 15, 2007

10.3928/1081597X-20080601-08

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