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Kim and Choi: Determine a Proper Axial Length by Ultrasonic Biometry in Opaque Hydrophilic Acrylic Intraocular Lens
Original Article

J Korean Ophthalmol Soc 2008;49(9):1453-1460.

Published online: 7 September 2008

DOI: https://doi.org/10.3341/jkos.2008.49.9.1453

Determine a Proper Axial Length by Ultrasonic Biometry in Opaque Hydrophilic Acrylic Intraocular Lens

Sang Hyuk Kim, M.D., Si Hwan Choi, M.D.

Department of Ophthalmology, College of Medicine, Chungnam National University, Daejeon, Korea

Address reprint requests to Si Hwan Choi, M.D. Department of ophthalmology, Chungnam National University Hospital #640 Daesa-dong, Jung-gu, Daejeon 301-846, Korea Tel: 82-42-280-7604, Fax: 82-42-255-3745, E-mail: shchoi@cnu.ac.kr

Received 14 May 2008       Accepted 29 January 2008

Copyright © 2008 Korean Ophthalmological Society

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose

To investigate the accuracy of measuring ultrasonic axial lengths using A-scan (Ocuscan®, Alcon, USA) on opaque intraocular lenses after hydrophilic lens (ACRL-160®, Ophthalmed, USA) implantation.

Methods

We measured axial length through ultrasonic biometry prior to intraocular lens exchange. Twelve eyes of 14 patients who had intraocular lens opacity following hydrophilic acryl lens implantation were examined in a clinical study. We compared pre-cataract operative axial lengths to pre-IOL exchange axial lengths. The pre-IOL exchange axial lengths were measured in aphakic and pseudophakic modes. In the pseudophakic mode, the ultrasound velocity through an IOL was set at a rate ranging between 1,500 m/sec to 2,200 m/sec.

Results

The pre-IOL exchange axial lengths in the pseudophakic mode at the rate of 1,600 m/sec in lens velocity were the closest to pre-cataract operative values ( p=0.88).

Conclusions

When pre-cataract operative axial length is known with a hydrophilic acrylic intraocular lens, previous values may be used for IOL exchange of an opacity patient. If not, however, the closest values to pre-cataract operative axial lengths may be obtained by setting the velocity in the pseudophakic mode to a lens velocity rate of 1,600 m/sec.

Keywords: Axial lengths, Hydrophilic acryl lens, IOL opacity, Ultrasonic Biometry

References

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Figure 1.
Slit lamp photographs of opaque hydrophilic acrylic intraocular lens.
jkos-49-1453f1.tif
Figure 2
. (A) Ultrasonic analyzer 5601A (Panametric, USA) measures for the measurement of ultrasonic velocity in hydrophilic acrylic lens (ACRL-C160®, Ophthalmed, USA). (B) Result of the measurement: Ultrasonic velocity shows 2008 m/sec.
jkos-49-1453f2.tif
Figure 3.
The result of axial length measurement at pre-cataract operation and pre-IOL exchange (aphakic/pseudophakic mode). (A)=aphakic mode; (B)=pseudophakic mode (lens velocity, 1,600 m/sec); (C)=pseudophakic mode (lens velocity, 2,000 m/sec); (D)=pseudophakic mode (lens velocity, 2,200 m/sec).
jkos-49-1453f3.tif
Table 1.
Visual acuity at presentation of pre- and post-IOL exchange
Visual acuity∗ pre-IOL exchange post-IOL exchange p-value†
Visual acuity∗ No. of eyes〔 n (%)〕 No. of eyes〔 n (%)〕 p-value
<0.1 2 (14.3) 1 (7.1)
0.1-0.2 11 (78.6) 1 (7.1)
0.3-0.4 1 (7.1) 1 (7.1)
0.5-0.6 3 (21.4)
0.7-0.8 6 (42.9)
>0.8 2 (14.3)
Average (LogMAR) 0.75±0.15 0.33±0.32 0.01

∗ Visual acuity of Dr. Hahn’s standard test chart at 5 m

† Wilcoxon signed rank test.

Table 2.
The results of measurement of axial length in opaque IOL (Mean±SD)
Axial length (mm) p-value∗
Pre-Cataract op. 23.40±0.69 　
IOL opacity
Aphakic mode 23.01±0.56 0.01
Pseudophakic mode
1,500 m/sec 23.05±0.57 0.02
1,550 m/sec 23.25±0.63 0.27
1,600 m/sec 23.39±0.65 0.88
1,650 m/sec 23.59±0.70 0.12
1,700 m/sec 23.69±0.57 0.04
1,750 m/sec 23.86±0.62 0.02
1,800 m/sec 24.01±0.57 0.00
1,850 m/sec 24.16±0.63 0.00
1,900 m/sec 24.33±0.60 0.00
2,000 m/sec 24.55±0.47 0.02
2,200 m/sec 25.21±0.67 0.03

∗ Wilcoxon signed rank test, compared to pre-cataract op. axial length.

Table 3.
The results of axial length and keratometry at pre-cataract op. and post-IOL exchange
Patient Pre-CA AL (mm) Pseudophakic mode* Keratometry (diopters)
Pre-op IOL opacity
Pt. #1 - L 23.02 22.52 44.38 44.35
Pt. #2 - R 23.59 23.55 42.32 42.20
Pt. #2 - L 23.70 23.79 42.07 42.19
Pt. #3 - L 23.10 23.06 41.75 41.75
Pt. #4 - R 22.55 22.91 45.75 45.43
Pt. #5 - R 22.79 22.90 44.88 43.38
Pt. #6 - R 22.43 22.45 45.94 46.99
Pt. #7 - L 23.02 23.10 45.25 45.25
Pt. #8 - L 24.04 23.98 43.00 43.12
Pt. #9 - L 24.21 24.25 42.38 42.87
Pt. #10 - L 23.38 23.30 44.25 42.87
Pt. #11 - R 25.02 24.78 44.00 44.13
Pt. #11 - L 23.37 23.40 43.75 43.88
Pt. #12 - R 23.39 23.41 38.63 38.94
Average 23.40±0.69 23.38±0.65 43.45±1.95 43.38±1.93

Pre-CA=pre-cataract operation; AL=axial length.

Table 4.
Comparison between expected refractive error by axial length measured at pre-cataract, pre-IOL exchange (psuedophaki mode, 1,600 m/sec) and manifested refractive error at post-IOL exchange
Patient Pre-Cataract Pseudophakic mode Post-IOL exchange (diopters)
Pt. #1 - L -0.13 +1.13 -0.25
Pt. #2 - R -0.13 -0.04 -0.13
Pt. #2 - L -0.01 -0.20 -0.38
Pt. #3 - L -0.11 -0.03 -
Pt. #4 - R -0.18 -0.65 -
Pt. #5 - R +0.08 -0.17 -0.75
Pt. #6 - R -0.03 -0.08 -0.25
Pt. #7 - L -0.12 -0.29 -0.50
Pt. #8 - L -0.05 +0.07 -0.38
Pt. #9 - L +0.12 +0.04 -0.25
Pt. #10 - L +0.17 +0.34 +0.50
Pt. #11 - R +0.06 +0.50 +0.25
Pt. #11 - L +0.12 +0.05 +0.25
Pt. #12 - R -0.05 -0.09 -
Average -0.02±0.11 +0.04±0.41 -0.19±0.09
p-value∗ 0.97 0.08

- =unchecked

‗ Wilcoxon signed rank test, compared to expected refractive error by axial length at pre-cataract operation.

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