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Estimation of intraocular lens power calculation after myopic corneal refractive surgery: using corneal height in anterior segment optical coherence tomography.

Kim DH, Kim MK, Wee WR - Korean J Ophthalmol (2015)

Bottom Line: Mean CH, ELPest, and ELPm were 3.71 ± 0.23, 7.74 ± 1.09, 5.78 ± 0.26 mm, respectively.The ELPm and ELPest were linearly correlated (ELPest = 1.841 × ELPm - 2.018, p = 0.023, R = 0.410) and ELPconv and Pconv agreed well with ELPest and Preal, respectively.Eyes within ±0.5, ±1.0, ±1.5, and ±2.0 diopters of the calculated Pconv, were 23.3%, 66.6%, 83.3%, and 100.0%, respectively.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea. ; Laboratory of Ocular Regenerative Medicine and Immunology, Seoul Artificial Eye Center, Seoul National University Hospital Clinical Research Institute, Seoul, Korea.

ABSTRACT

Purpose: To investigate the feasibility of estimating effective lens position (ELP) and calculating intraocular lens power using corneal height (CH), as measured using anterior segment optical coherence tomography (AS-OCT), in patients who have undergone corneal refractive surgery.

Methods: This study included 23 patients (30 eyes) who have undergone myopic corneal refractive surgery and subsequent successful cataract surgery. The CH was measured with AS-OCT, and the measured ELP (ELPm) was calculated. Intraocular lens power, which could achieve actual emmetropia (Preal), was determined with medical records. Estimated ELP (ELPest) was back-calculated using Preal, axial length, and keratometric value through the SRK/T formula. After searching the best-fit regression formula between ELPm and ELPest, converted ELP and intraocular lens power (ELPconv, Pconv) were obtained and then compared to ELPest and Preal, respectively. The proportion of eyes within a defined error was investigated.

Results: Mean CH, ELPest, and ELPm were 3.71 ± 0.23, 7.74 ± 1.09, 5.78 ± 0.26 mm, respectively. The ELPm and ELPest were linearly correlated (ELPest = 1.841 × ELPm - 2.018, p = 0.023, R = 0.410) and ELPconv and Pconv agreed well with ELPest and Preal, respectively. Eyes within ±0.5, ±1.0, ±1.5, and ±2.0 diopters of the calculated Pconv, were 23.3%, 66.6%, 83.3%, and 100.0%, respectively.

Conclusions: Intraocular lens power calculation using CH measured with AS-OCT shows comparable accuracy to several conventional methods in eyes following corneal refractive surgery.

No MeSH data available.


Related in: MedlinePlus

An anterior segment optical coherence tomography image. The measured corneal height (CHm) was defined as the distance between the posterior corneal surface and the intersection between the perpendicular lines.
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Figure 1: An anterior segment optical coherence tomography image. The measured corneal height (CHm) was defined as the distance between the posterior corneal surface and the intersection between the perpendicular lines.

Mentions: Preoperative evaluations included measurement of corneal radius, AL, and CH. Corneal radius was measured with an autokeratorefractometer (Nidek KR-8900; Topcon, Tokyo, Japan) and IOL Master (Carl-Zeiss Meditec, Dublin, CA, USA). The AL was measured with contact A-scan ultrasonography (Axis II PR; Quantel Medical, Clermont-Ferrand, France) and IOL Master. Topographic analysis with Orbscan IIz (Bausch & Lomb, Claremont, CA, USA) was also performed. CH was measured using Visante AS-OCT (Carl Zeiss Meditec). To measure CH, a line connecting the two anterior chamber angles was drawn in the AS-OCT image. A line was then drawn from the corneal vertex, perpendicular to the line connecting the anterior chamber angles. The distance between the posterior corneal surface and the intersection point of these two lines was defined as measured CH (CHm) (Fig. 1). The built-in software of the Visante AS-OCT automatically CHm when the posterior corneal surface and the intersection point of the angle and the corneal vertex lines were specified. All AS-OCT examinations were performed by one examiner.


Estimation of intraocular lens power calculation after myopic corneal refractive surgery: using corneal height in anterior segment optical coherence tomography.

Kim DH, Kim MK, Wee WR - Korean J Ophthalmol (2015)

An anterior segment optical coherence tomography image. The measured corneal height (CHm) was defined as the distance between the posterior corneal surface and the intersection between the perpendicular lines.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4446561&req=5

Figure 1: An anterior segment optical coherence tomography image. The measured corneal height (CHm) was defined as the distance between the posterior corneal surface and the intersection between the perpendicular lines.
Mentions: Preoperative evaluations included measurement of corneal radius, AL, and CH. Corneal radius was measured with an autokeratorefractometer (Nidek KR-8900; Topcon, Tokyo, Japan) and IOL Master (Carl-Zeiss Meditec, Dublin, CA, USA). The AL was measured with contact A-scan ultrasonography (Axis II PR; Quantel Medical, Clermont-Ferrand, France) and IOL Master. Topographic analysis with Orbscan IIz (Bausch & Lomb, Claremont, CA, USA) was also performed. CH was measured using Visante AS-OCT (Carl Zeiss Meditec). To measure CH, a line connecting the two anterior chamber angles was drawn in the AS-OCT image. A line was then drawn from the corneal vertex, perpendicular to the line connecting the anterior chamber angles. The distance between the posterior corneal surface and the intersection point of these two lines was defined as measured CH (CHm) (Fig. 1). The built-in software of the Visante AS-OCT automatically CHm when the posterior corneal surface and the intersection point of the angle and the corneal vertex lines were specified. All AS-OCT examinations were performed by one examiner.

Bottom Line: Mean CH, ELPest, and ELPm were 3.71 ± 0.23, 7.74 ± 1.09, 5.78 ± 0.26 mm, respectively.The ELPm and ELPest were linearly correlated (ELPest = 1.841 × ELPm - 2.018, p = 0.023, R = 0.410) and ELPconv and Pconv agreed well with ELPest and Preal, respectively.Eyes within ±0.5, ±1.0, ±1.5, and ±2.0 diopters of the calculated Pconv, were 23.3%, 66.6%, 83.3%, and 100.0%, respectively.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea. ; Laboratory of Ocular Regenerative Medicine and Immunology, Seoul Artificial Eye Center, Seoul National University Hospital Clinical Research Institute, Seoul, Korea.

ABSTRACT

Purpose: To investigate the feasibility of estimating effective lens position (ELP) and calculating intraocular lens power using corneal height (CH), as measured using anterior segment optical coherence tomography (AS-OCT), in patients who have undergone corneal refractive surgery.

Methods: This study included 23 patients (30 eyes) who have undergone myopic corneal refractive surgery and subsequent successful cataract surgery. The CH was measured with AS-OCT, and the measured ELP (ELPm) was calculated. Intraocular lens power, which could achieve actual emmetropia (Preal), was determined with medical records. Estimated ELP (ELPest) was back-calculated using Preal, axial length, and keratometric value through the SRK/T formula. After searching the best-fit regression formula between ELPm and ELPest, converted ELP and intraocular lens power (ELPconv, Pconv) were obtained and then compared to ELPest and Preal, respectively. The proportion of eyes within a defined error was investigated.

Results: Mean CH, ELPest, and ELPm were 3.71 ± 0.23, 7.74 ± 1.09, 5.78 ± 0.26 mm, respectively. The ELPm and ELPest were linearly correlated (ELPest = 1.841 × ELPm - 2.018, p = 0.023, R = 0.410) and ELPconv and Pconv agreed well with ELPest and Preal, respectively. Eyes within ±0.5, ±1.0, ±1.5, and ±2.0 diopters of the calculated Pconv, were 23.3%, 66.6%, 83.3%, and 100.0%, respectively.

Conclusions: Intraocular lens power calculation using CH measured with AS-OCT shows comparable accuracy to several conventional methods in eyes following corneal refractive surgery.

No MeSH data available.


Related in: MedlinePlus