Comparison of the accuracy of intraocular lens power calculations for cataract surgery in eyes after phototherapeutic keratectomy.
OBJECTIVE
To compare the accuracy of several methods of intraocular lens (IOL) power calculations used for cataract surgery in eyes treated with phototherapeutic keratectomy (PTK) that results in changes in the anterior corneal surface and axial length; these results make power calculations less predictable.


METHODS
We evaluated the medical records of 23 eyes of 13 patients (mean age, 68.8 years; range 62-80 years) who underwent cataract surgery after PTK at Keio University Hospital, Tokyo, Japan. The prediction error, defined as the difference between the estimated postoperative spherical equivalent and the postoperative manifest refraction at the spectacle plane, was calculated using five formulas: SRK/T, Haigis-L, Shammas-PL, Camellin-Calossi, and OKULIX ray tracing software. We compared the median values of the arithmetic and absolute prediction errors among the five formulas.


RESULTS
The median arithmetic errors after cataract surgery for the five formulas were 0.70 D (diopter) (range -0.41 to 2.78), -0.96 D (range -2.14 to 0.81), -0.81 D (range -1.89 to 1.15), -0.04 D (range -1.35 to 1.47), and 0.68 D (range -0.61 to 2.50), respectively.


CONCLUSIONS
The Camellin-Calossi formula is a good option for calculating IOL powers in eyes that underwent PTK.
Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
Yukari
Y
Yaguchi
Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan. fwic7788@mb.infoweb.ne.jp.
Kazuno
K
Negishi
Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
Megumi
M
Saiki
Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
Hidemasa
H
Torii
Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
Kazuo
K
Tsubota
D000368:Aged; D000369:Aged, 80 and over; D002386:Cataract / Q000150:complications*; D002387:Cataract Extraction; D003317:Corneal Dystrophies, Hereditary / Q000150:complications* / Q000601:surgery; D006801:Humans; D007910:Lenses, Intraocular; D008875:Middle Aged; D018903:Photorefractive Keratectomy; D012029:Refraction, Ocular; D015203:Reproducibility of Results; D012189:Retrospective Studies
Band keratopathy; Camellin–Calossi formula; Granular corneal dystrophy type 2; Intraocular lens power calculation; Phototherapeutic keratectomy