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Measurement of Angle Lamda (λ) with Pentacam in Normal Controls and Anisometropia Patients
Ann Optom Contact Lens 2019;18:86-90
Published online September 25, 2019
© 2019 The Korean Optometry & Contact Lens Study Society

Sang Min Lee, MD, Helen Lew, MD, PhD

Department of Ophthalmology, CHA Bundang Medical Center, CHA University, Seongnam, Korea
Correspondence to: Helen Lew, MD, PhD
Department of Ophthalmology, CHA Bundang Medical Center, #59 Yatap-ro, Bundang-gu, Seongnam 13496, Korea
Tel: 82-31-780-5330, Fax: 82-31-780-5333
Received March 7, 2019; Revised June 20, 2019; Accepted August 6, 2019.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Purpose: To measure and compare angle lambda between normal controls and anisometropia patients.
Methods: We conducted a retrospective cross-sectional study including 134 normal controls and 34 anisometropia patients who visited our clinic with visual acuity test from April 2017 to January 2018. All patients underwent cycloplegic or manifest refraction. Classified as anisometropia group, when the difference in binocular spherical equivalent was greater than 2.0 diopter (D). The anterior segment of the eye and axial length were measured using Pentacam (Oculus, Wetzler, Germany) and IOL master 700 (Carl Zeiss Meditec AG, Oberkochen, Germany). The angle lambda was calculated by the law of cosine with the data from Pentacam.
Results: There was no significant difference in the mean age and sex ratio between control and anisometropic groups. The angle lambda of control and anisometropia group were 3.56 ± 1.69° and 2.87 ± 1.58° and the spherical equivalent were -0.19 ± 2.82 D and -2.30 ± 4.65 D. Correlations between the spherical equivalent and the angle lambda showed a positive correlation (correlation coefficient = 0.636, p < 0.01). There was no significant difference in axial length, anterior chamber depth and lens thickness between control and anisometropia group. Difference of angle lambda in anisometropia group was bigger than controls (p < 0.05).
Conclusions: There was positive correlation between angle lambda and spherical equivalent, which were in agreement with the results from previous studies. However, the angle lambda in this study was measured at monocular fixation and further studies will be need on angle lambda in binocular fixation.
Keywords : Anisometropia; Angle lambda; Angle kappa; IOL master; Pentacam

September 2019, 18 (3)