[Evaluation of the residual refractive error of hydrophobic acrylic intraocular lenses].
BACKGROUND
The postoperative refractive status after cataract surgery is mainly characterised by the preoperatively determined intraocular lens (IOL) power. Beyond this scope we evaluated the refractive error of hydrophobic acrylic IOLs.


METHODS
Standard phacoemulsification with implantation of hydrophobic acrylic IOLs ("yellow" HOYA AF-1 YA60BB n = 63, Alcon MA 60AC n = 52, AMO AR 40e n = 131) was performed in 246 consecutive patients (first eyes). The "yellow" AF-1 YA60BB was mainly implanted in eyes with macular drusen, whereas the other two IOL types were selected statistically. Eyes with no guaranteed postoperative follow-up and eyes with previous surgical interventions were excluded. Beside a complete ophthalmological examination, biometry (IOLMaster, Zeiss) and objective refraction (Nidek) were assessed. IOL power was predicted according to the Holladay-I formula and with the IOL-specific constants provided by the manufacturer. The objective refraction was evaluated again four to six weeks after cataract surgery. The "predictive error" (PE) and the absolute value of PE (APE) were defined as the deviation of the postoperative objective refraction to the target refraction.


RESULTS
Mean target refraction of the 246 eyes was - 0.54 +/- 0.68 D and PE was - 0.24 +/- 0.75 D (APE: 0.57 D). With the MA 60AC a PE/APE of - 0.24 +/- 0.71 D/0.59 D was achieved. With the AR 40e the PE/APE was - 0.10 +/- 0.73 D/0.51 D, and with the AF-1 YA60BB the PE/APE yielded - 0.54 +/- 0.73 D/0.69 D. With the AR 40e/MA 60AC/AF-1 YA60BB, altogether 77%/75%/62% ranged in three-quarters of a dioptre around the target refraction.


CONCLUSIONS
In general, four to six weeks after cataract surgery the achieved spherical equivalent was more myopic than the target refraction. The AR 40e yielded the lowest PE/APE, whereas the AF-1 YA60BB resulted in the highest PE/APE. If this trend is manifested by other investigators with a larger sample size, the manufacturer should optimise the lens specific constants.
Wald
E
E
Konventhospital der Barmherzigen Brüder Linz, Osterreich.
Viestenz
A
A
Langenbucher
A
A
Schönherr
U
U
D000180:Acrylic Resins; D000328:Adult; D002386:Cataract / Q000150:complications / Q000628:therapy*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D011379:Prognosis; D012030:Refractive Errors / Q000175:diagnosis* / Q000209:etiology / Q000517:prevention & control*; D016896:Treatment Outcome
D000180:Acrylic Resins