Topographically-guided laser in situ keratomileusis to treat corneal irregularities.
OBJECTIVE
To evaluate the predictability and safety of topographically guided laser in situ keratomileusis (LASIK) to treat corneal irregularities.


METHODS
Prospective, noncomparative interventional case series.


METHODS
Twenty-seven patients (29 eyes) with postsurgical corneal irregularities, divided into four subgroups (postkeratoplasty, 6 eyes; posttrauma, 6 eyes; postphotorefractive keratectomy (PRK)/LASIK with decentered or small ablations, 11 eyes; post-PRK/LASIK with central islands, 6 eyes).


METHODS
LASIK was performed using the Automatic Corneal Shaper and the Keracor 117 C spot-scanning excimer laser (Bausch & Lomb Surgical Technolas, Munich, Germany). Individual ablation patterns were calculated on the basis of axial radii of curvature data obtained with the Corneal Analysis System (EyeSys Premier, Irvine, CA).


METHODS
Change of corneal topography pattern, patient satisfaction, manifest spectacle refraction, and visual acuity at 12 months after surgery.


RESULTS
Corneal topography showed improved corneal regularity in 66% of eyes in the postkeratoplasty group, whereas 34% remained irregular. In the posttrauma group, 83% improved and 17% remained irregular. In the decentered/small optical zone group, 91 % improved and 9% remained irregular. In the central islands group, 50% improved and 50% remained irregular. Refractive cylinder decreased from 5.83 +/- 1.25 diopters (D) to 2.96 +/- 1.23 D in the postkeratoplasty group (P = 0.01), from 2.21 +/- 1.35 D to 0.50 +/- 0.84 D in the posttrauma group (P = 0.001), from 0.73 +/- 0.71 D to 0.36 +/- 1.05 D in the decentered/small optical zone group (NS), and from 1.42 +/- 1.13 D to 0.50 +/- 0.84 D in the central island group (P = 0.01). Uncorrected visual acuity improved from 20/200 +/- 0.07 to 20/50 +/- 0.17 in the postkeratoplasty group (P = 0.01), from 20/83 +/- 0.12 to 20/50 +/- 0.28 in the posttrauma group (P = 0.01), from 20/60 +/- 0.16 to 20/50 +/- 0.29 in the decentered/small optical zone group (NS), and from 20/71 +/- 0.12 to 20/60 +/- 0.24 in the central island group (NS).


CONCLUSIONS
The topographically-guided LASIK method used in this study resulted in a significant reduction of refractive cylinder, a significant increase of uncorrected visual acuity, and improved corneal regularity in a large percentage of patients with severe corneal irregularities such as decentered/small optical zones after LASIK or irregular astigmatism after keratoplasty or trauma. With small irregularities such as central islands, results were sufficiently poor to advise against the use of our technique in these patients.
Knorz
M C
MC
Department of Ophthalmology, Klinikum Mannheim, Mannheim, Germany.
Jendritza
B
B
D000293:Adolescent; D000328:Adult; D001251:Astigmatism / Q000209:etiology / Q000601:surgery*; D002648:Child; D003315:Cornea / Q000601:surgery*; D019781:Corneal Topography; D005131:Eye Injuries / Q000150:complications; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D015948:Keratoplasty, Penetrating / Q000009:adverse effects; D054018:Lasers, Excimer; D008875:Middle Aged; D018903:Photorefractive Keratectomy / Q000009:adverse effects; D011446:Prospective Studies; D012086:Reoperation; D012449:Safety; D016896:Treatment Outcome; D014792:Visual Acuity