Comparison of Functional Vision Provided by AMO Tecnis Z9000 and Alcon SA60AT Acrysof

This study is to compare intraindividually the functional vision provided by two different posterior chamber intraocular lenses: AMO Tecnis Z9000 and Alcon SA60AT Acrysoft. To see if the aspherical intraocular lenses provide better functional vision than traditional spherical intraocular lenses.

In this prospective study, 20 patients with bilateral catarct presenting for cataract surgery are randomly assigned to recieve an aspherical intraocular lens(AMO Tecnis Z9000) in one eye and a spherical intraocular lens(Alcon SA60AT Acrysof)in the other. All surgeries are performed by one experienced surgeon(Fung-Rong Hu,MD)with clear cornea small incision phacoemulsification and in-the-bag posterior chamber intraocular implantation.

The patients are followed for 3 months, and postoperative contrast sensitivity, contrast acuity, corneal \& total ocular high-ordered aberrations are measured and compared intraidividually between two different IOL groups.

Outcome Measurement:

1. Contrast sensitivity testing: measured with spectacle correction for the target distance of three meters using wall-mounted FACT sine-wave grating chart with nine levels of contrast.The graphic contrast sensitivity is recorded as a log functional units on the y-axis and displayed for five spatial frequency targets (1.5, 3, 6, 12, 18 cycles per degree (cpd))on x- axis.
2. Contrast acuity testing: measured with spectacle correction for the target distance of three meters using logMAR letter chart(Precision Vision®)represented on a wall-mounted illuminator cabinet.Two types of contrast charts are used, high contrast(Cat.No.2103 SLOAN translucent chart)and low contrast(Cat.No.2132 10% SLOAN translucent chart),and are tested under both photopic and mesopic conditions.
3. Pupil diameters: measured by Colvard infrared pupillometer (Oasis. Medical, Glendora, CA, USA )under both photopic and mesopic luminance levels.
4. Corneal aberration analysis: performed with TMS-4 (Tomey, Japan).The corneal HOAs are described with Zernike polynomials of 3rd-to 5th- order root-mean-square(RMS)of central 6mm diameter using VOLPro 6.89 software(Fa. Sarver and Associates, Carbondale. Ill, USA).
5. Total ocular aberration analysis: performed with a Hartmann-Shack aberrometer(Zywave, Bausch \& Lomb Inc., Rochester, New. York)under maximal mydriasis with Mydrin-P(phenylephrine hydrochloride 0.5% and tropicamide 0.5%, Santen).The wavefront errors were described using Zernike polynomials RMS for total HOA at pupil diameter of 5 mm and 6 mm, primary spherical (Z 4,0) and 3rd-to 5th-order aberration at pupil diameter of 6 mm.

Data Analysis:

* Mann-Whitney U matched-paired test was used with STATA software
* P values of 0.05 or less were considered statistically significant

Eligibility Criteria:
Inclusion Criteria:

* Bilateral cataracts, eligible for phacoemulsification with primary implantation of a posterior chamber IOL
* Willing and able to comply with scheduled visits and other study procedures

Exclusion Criteria:

* Preoperative ocular pathology potentially affect visual acuity. EX: diabetic retinopathy, macular degeneration, corneal opacity, glaucoma, visual field defect...etc.
* Previous ocular surgery. Ex: refractive surgery, vitreoretinal surgery...etc.
* Patients who cannot cooperative with the study procedures