Autorefraction Versus Subjective Refraction In A Novel Pentafocal Intraocular Lens

To evaluate the correlation between automated refraction (AR) and subjective refraction (SR) after implantation of a novel hydrophilic diffractive pentafocal IOL, the Intensity SL (Hanita lenses, Israel) . With multifocal IOL the target refraction is very important in attaining optimal results. These results are verified by measuring the patients visual acuity and refraction. In many instances automated refraction may give an erroneous value because the measurement is done on a multifocal IOL optic. It is important to be aware of systematic errors in automated refraction when basing the subjective refraction on the measurement. 

Private refractive surgery clinic affiliated with an academic ophthalmology department, the Netherlands.

In a prospective consecutive case series, 24 patients (48) eyes) implanted with a pentafocal IOL (Intensity SL) were included. At 3 months postoperatively the visual acuity, autorefraction, and subjective refraction were obtained, monocularly. Automated refraction was performed with the Topcon-KR8100 (Topcon corp., Nagoya, Japan). Visual acuity was measured in LogMAR in standardized vision lanes. Correlation between the automated and the subjective refraction in terms of spherical equivalent (SE), Sphere(S), and cylinder (C) was done. Analysis of J0 and J45 vectors was performed.  

At 3 months postoperatively  mean uncorrected Logmar visual acuity was 0.025 + 0.08 (-0.13 to 0.3) and significantly better than preoperatively (P<0.05). The mean Sphere with AR was -0.96 + 0.43 D, and -0.15 + 0.35D with SR. The mean cylinder with AR was -0.46 + 0.34 with AR and -0.11 + 0.25 with SR. Mean soherical equivalent was -0.92 + 0.39 with AR and -0.20 + 0.34 with SR. All these diffrences were highly statistically significant (P<0.001). In terms of J0 and J45 the mean differences were up to 0.02D and not statistically significant. In terms of spherical equivalent autorefraction yielded a more myopic results than SR in 96% (46/48 eyes) and in terms of sphere in 77% of the eyes (37/48). 

In this study of differences between automated refraction and subjective refraction we found a mean difference of 0.54D in the sphere and 0.72 in the spherical equivalent. The automated refraction had a systematic myopic measurement error. When doing subjective refraction son patient implanted with multifocal IOLs one should keep in mind, that if automeated refraction is the starting point for subjective refraction, each type of premium IOL can have its own specific range of systematic error in the autorefraction, and this shoudl be taken into account during refraction of the patient.