Korean J Ophthalmol.  2014 Aug;28(4):285-291.

Higher Order Aberrations of the Corneal Surface after Laser Subepithelial Keratomileusis

• Jung HH
• Ji YS
• Oh HJ
• Yoon KC

Abstract

PURPOSE
To evaluate the changes of higher order aberrations (HOAs) before and after laser subepithelial keratomileusis (LASEK) and to analyze the influence of tear film instability on HOAs of the corneal surface after LASEK.
METHODS
In this cross-sectional study, 31 patients who underwent LASEK were divided into dry eye (16 patients, 32 eyes) and non-dry eye groups (15 patients, 30 eyes). Uncorrected distance visual acuity, spherical equivalent refraction, ablation depth, tear film parameters and Ocular Surface Disease Index (OSDI) questionnaire scores were evaluated in both groups. Total HOA root mean square (RMS), third-order coma, third-order trefoil and fourth-order spherical aberration (SA) of the corneal surface immediately and at 10 seconds after blinking were measured before and after surgery.
RESULTS
The total HOA RMS, coma, trefoil and SA significantly increased after LASEK compared with preoperative values in both groups. In the dry eye group, total HOA RMS, coma and trefoil significantly increased except for SA at 10 seconds after blinking compared with those measured immediately after blinking. In addition, the changes of total HOA RMS, coma and trefoil were negatively correlated with tear film break-up time (R = -0.420, -0.473 and -0.439, respectively), but positively correlated with OSDI score (R = 0.433, 0.499 and 0.532, respectively). In the non-dry eye group, there were no significant differences between HOAs measured at 10 seconds after blinking and those measured immediately after blinking.
CONCLUSIONS
The HOAs including coma, trefoil and SA significantly increased after LASEK. The tear film instability in the dry eye can be associated with more deterioration of the optical quality after LASEK, due to more significant increase of total HOA RMS, coma and trefoil.

Keyword

Higher order aberration; Laser subepithelial keratomileusis; Tear film instability

MeSH Terms

Adult
Cornea/*physiopathology
Corneal Wavefront Aberration/*etiology/physiopathology
Cross-Sectional Studies
Dry Eye Syndromes/*physiopathology
Female
Humans
Keratectomy, Subepithelial, Laser-Assisted/*adverse effects
Lasers, Excimer/*therapeutic use
Male
Surveys and Questionnaires
Tears/*physiology
Visual Acuity/physiology
Young Adult

Figure

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  Fig. 1 Changes of total higher order aberration root mean square (A), coma (B), trefoil (C) and spherical aberration (D) between values measured immediately after blinking and those measured at 10 seconds after blinking in the dry eye and the non-dry eye groups. *p < 0.05 (comparison of values measured immediately after blinking and those measured at 10 seconds after blinking).

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