The Preoperative Prognostic Factors for Outcome After LASEK Using the MEL60

Jae Ryun Kim; Jung Sub Kim; Eun Jung Jun; Hyun Seung Kim; Sung Kun Chung

doi:10.3341/jkos.2010.51.8.1064

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Kim, Kim, Jun, Kim, and Chung: The Preoperative Prognostic Factors for Outcome After LASEK Using the MEL60

Original Article

J Korean Ophthalmol Soc 2010;51(8):1064-1070.

Published online: 7 September 2010

DOI: https://doi.org/10.3341/jkos.2010.51.8.1064

The Preoperative Prognostic Factors for Outcome After LASEK Using the MEL60

Jae Ryun Kim, MD¹, Jung Sub Kim, MD², Eun Jung Jun, MD¹, Hyun Seung Kim, MD¹, Sung Kun Chung, MD¹

¹Department of Ophthalmology, Inje university, Pusan Paik Hospital, Busan, Korea

²Crystal Eye Hospital, Busan, Korea

Address reprint requests to Sung Kun Chung, MD Department of Ophthalmology and Visual Science, St. Mary's Hospital #62, Yeouido-dong, Yeongdeungpo-gu, Seoul 150-713, Korea Tel: 82-2-3779-1243, Fax: 82-2-761-6869, E-mail: eyedoc@catholic.ac.kr

Received 8 September 2009 Accepted 1 June 2010

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 preoperative clinical factors affecting the refractive outcome after laser-assisted subepithelial keratomileusis (LASEK).

Methods

This retrospective study was conducted on 58 patients (116 eyes) who underwent bilateral LASEK using the MEL60. The outcome efficacy and predictability of LASEK was examined by analyzing data including age, gender, pre-operative uncorrected visual acuity, preoperative refraction (spherical equivalent and cylindrical diopter), central corneal thickness, tear breakup time, and Schirmer test through multiple logistic regression analysis.

Results

The preoperative factor associated with postoperative uncorrected visual acuity was the amount of preoperative spherical equivalent. Greater preoperative spherical equivalent was associated with decreased efficacy. Predictability was also associated with the amount of preoperative spherical equivalent. Greater preoperative spherical equivalent was associated with decreased predictability. The other preoperative factors including sex, age, preoperative uncorrected visual acuity, amount of preoperative cylinder diopter, intraocular pressure, tear breakup time, Schirmer test and central corneal thickness did not show any association with efficacy or predictability.

Conclusions

The preoperative spherical equivalent was determined as the most important prognosis factor in LASEK, as it is in PRK or LASIK.

Keywords: Factor, LASEK, Refractive outcome

References

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Table 1.

Characteristics of eyes for LASEK^*

Parameter
Age (yr)	25.8 ± 5.43
Gender (male/female)	19/39
Preoperative UCVA^† (logMAR)	1.18 ± 0.37
Preoperative manifest refractive SE^‡ (D)	−4.90 ± 1.50
Pachymetry (µm)	548.9 ± 40.5
Schirmer test (mm)	16.81 ± 5.12
Tear breakup time (second)	7.08 ± 2.77
Intraocular pressure (mmHg)	15.16 ± 2.78
Mild myopia	32 eyes (27.6%)
Moderate myopia	53 eyes (45.7%)
High myopia	31 eyes (26.7%)
Total	116 eyes

LASEK^*=laser-assisted subepithelial keratomileusis

UCVA^†= uncorrected visual acuity

SE^‡=spherical equivalent.

Table 2.

Preoperative characteristics associated with UCVA^* <20/25 6 months after LASEK^† (Efficacy)

Factor		No. of eyes	Odd ratio	95% CI^‡	^∏ P value
Sex	Male	38 (32.7%)	1
	Female	78 (67.3%)	3.974	0.563∼28.071	0.167
IOP	≤15	59 (50.8%)	1
	>15	57 (49.2%)	1.145	0.300∼4.364	0.843
Age	<20	8 (6.9%)	1
	20≤<30	84 (72.4%)	0.101	0.007∼1.557	0.101
	30≤	24 (21.7%)	0.064	0.003∼1.248	0.070
SE^§	<-4D	32 (27.6%)	1
	−4D≤<-6D	53 (45.7%)	5.614	0.432∼72.975	0.187
	−6D≤	31 (26.7%)	20.939	1.464∼299.437	0.025
Astigmatism	<-1D	75 (64.6%)	1
	−1D≤<-2D	29 (25%)	1.958	0.494∼7.762	0.339
	−2D≤	12 (10.4%)	0.465	0.038∼5.643	0.548
Tear breakup time	≥10	42 (36.2%)	1
	<10	74 (63.8%)	2.192	0.309∼15.554	0.432
Schirmer	≥10	99 (85.4%)	1
	<10	17 (14.6%)	0.813	0.121∼5.436	0.831
Preoperative UCVA^*	≥2/20	29 (25%)	1
	<2/20	87 (75%)	0.897	0.149∼5.404	0.905
Preoperative corneal thickness	<550	52 (44.8%)	1
	≥550	64 (55.2%)	3.585	0.841∼15.275	0.084

^* UCVA = uncorrected visual acuity

LASEK^† = laser assisted subepithelial keratomileusis

CI^‡ = confidence interval

SE^§ = spherical equivalent

p^∏ = multiple logistic regression analysis.

Table 3.

Average of uncorrected visual acuity and spherical equivalent 6 months after LASEK^*

Group	UCVA^† (logMAR)	SE^‡
<-4.0D	0.036 ± 0.095	−0.35 ± 0.41
−4.0D≤<-6.0D	0.040 ± 0.073	−0.60 ± 0.62
−6.0D≤	0.087 ± 0.116	−0.72 ± 0.85

LASEK^*=laser assisted subepithelial keratomileusis

UCVA^†= uncorrected visual acuity

SE^‡ = spherical equivalent.

Table 4.

Preoperative characteristics associated with refractive error outside ± 1.0D 6 months after LASEK^* (Predictability)

Factor		No. of eyes	Odd ratio	95% CI^‡	^∏ P value
Sex	Male	38 (32.7%)	1
	Female	78 (67.3%)	1.182	0.278–5.027	0.821
IOP	≤15	59 (50.8%)	1
	>15	57 (49.2%)	3.107	0.993–9.722	0.051
Age	<20	8 (6.9%)	1
	20≤<30	84 (72.4%)	0.150	0.015–1.511	0.107
	30≤	24 (21.7%)	0.173	0.014–2.127	0.170
SE^§	<-4D	32 (27.6%)	1
	−4D≤<-6D	53 (45.7%)	11.907	1.172–120.994	0.036
	−6D≤	31 (26.7%)	18.150	1.567–210.245	0.020
Astigmatism	<-1D	75 (64.6%)	1
	−1D≤<-2D	29 (25%)	1.520	0.419–5.516	0.524
	−2D≤	12 (10.4%)	4.253	0.874–20.705	0.073
Tear breakup time	≥10	42 (36.2%)	1
	<10	74 (63.8%)	0.952	0.228–3.981	0.946
Schirmer	≥10	99 (85.4%)	1
	<10	17 (14.6%)	0.499	0.081–3.059	0.453
Preoperative UCVA^†	≥2/20	29 (25%)	1
	<2/20	87 (75%)	1.739	0.367–8.231	0.485
Preoperative corneal thickness	<550	52 (44.8%)	1
	≥550	64 (55.2%)	1.331	0.397–4.457	0.643

^* LASEK=laser assisted subepithelial keratomileusis

^† UCVA=uncorrected visual acuity

^‡ CI=confidence interval

^§ SE=spherical equivalent

^∏ p=multiple logistic regression analysis.

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