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I. W. Porter, K. L. Cohen; Are There Predictive Factors for Pseudophakic Pseudoaccommodation?. Invest. Ophthalmol. Vis. Sci. 2008;49(13):391. doi: https://doi.org/.
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To identify predictive factors for pseudophakic pseudoaccommodation (PP).
12 patients over age 60 with cataracts, no other eye disease, and BCVA >20/80 were enrolled prior to cataract surgery. Pre-operative manifest refraction, distance-corrected distance and near vision, and video keratoscopy were recorded. Following uncomplicated CE/IOL, all tests were repeated, as well as uncorrected distance and near vision. Patients were assigned to 3 groups - preoperative apparent accommodation (AA, 20/40 or better at distance and 20/40 or better at near with distance correction), postoperative PP (20/40 or better at distance and near uncorrected), and all other patients. Comparisons were made between the groups assessing for unique characteristics.
3 patients demonstrated AA preoperatively, one of whom retained this ability postoperatively. 2 other patients possessed PP and 7 patients had no AA. The 2 patients with preoperative AA that did not have PP both had myopic astigmatism by manifest refraction preoperatively but no astigmatism by manifest postoperatively. All 3 patients with PP had against the rule (ATR) myopic astigmatism postoperatively. Only 1 patient without PP had ATR myopic astigmatism. By simulated keratometry, 9/12 patients had the steep axis at 180 +/- 20 degrees both preoperatively and postoperatively, with no difference between the groups. RMS coma values ranged from 0.062 to 0.187 microns and did not vary signifcantly between the groups.
PP is the ability for patients to see well at distance and near following cataract surgery with monofocal lens placement. Many of the patients with this ability are pleased with their freedom from glasses postoperatively. Proposed mechanisms for this phenomenon include ATR myopic astigmatism, corneal multifocality, coma, and pupillary size. We are not aware of any studies that have attempted to measure AA preoperatively and correlated this to PP. 2 of 3 patients with AA did not possess PP. These 2 patients had no refractive astigmatism postoperatively, which could have limited their PP ability, and their preoperative astigmatism could have been due to cataracts. All patients with PP had ATR myopic astigmatism postoperatively, which has been shown to increase depth of focus. These 3 patients also had 0.75 to 1.25 diopters of ATR astigmatism preoperatively. More patients are needed to detect any possible difference in coma or simulated keratometry values between the groups. Coma may cause PP by increasing corneal multifocality. It may be reasonable to leave patients slightly myopic after cataract surgery if they have ATR astigmatism and are interested in PP.
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