Long-term visual outcome of dense bilateral congenital cataract

Background Dense congenital cataracts often cause severe visual impairment. The results of long-term follow-up of dense bilateral congenital cataract in China have not been well documented. The purpose of this study was to evaluate the long-term visual function in children who underwent cataract extraction for dense bilateral congenital cataract in southern part of China. Methods Medical records of children who underwent surgery of dense bilateral congenital cataract between January 1992 and December 2000 at Zhongshan Ophthalmic Center of Sun Yat-sen University were retroactively reviewed. In 38 children available for current follow-up, best corrected visual acuity （BCVA） and stereoscopic vision, as well as nystagmus, strabismus, and other complications, were evaluated. The mean follow-up period was 107.6 months （range 60 to 167 months）. Results The mean age of cataract extraction and secondary intraocular lens implantation were 5.6 months （range 3 to 12 months） and 4.2 years （range 2.4 to 15 years）, respectively. The mean BCVA was 0.25 in the better eye and 0.16 in the fellow eye. Stereoscopic vision was absent in all patients, and 3 children had simultaneous perception. Nystagmus was detected in all cases and strabismus in 35 cases. A high correlation was found between timing of cataract extraction and final BCVA of the better eye （r=-0.55, P=0.00）. A statistically significant difference was found in BCVA between post- and pre-treatment of amblyopia （t=5.65, P=0.00）. Conclusions Long-term visual function in children with dense bilateral congenital cataract was poor when cataract surgery was performed at age of 3 months or later. Earlier cataract surgery with adequate optical rehabilitation contributed to better visual outcome.

Comparison of higher-order aberrations and contrast sensitivity between Tecnis Z9001 and CeeOn 911A intraocular lenses:a prospective randomized study

Background The advent of wavefront technology in the past five years has provided some insight into the optical outcomes of cataract surgery. The Tecnis Z9001 intraocular lens （Tecnis IOL, AMO） with a modified prolate anterior surface was claimed to reduce or even eliminate ocular spherical aberration to improve the visual quality. The purpose of this study was to determine whether Tecnis IOLs can improve the quality of vision as evaluated by measuring visual acuity, wavefront aberration, and contrast sensitivity. Methods In an intraindividual prospective study, 20 patients with bilateral cataract were randomly assigned to receive a modified prolate anterior surface IOL （Tecnis Z9001, AMO） in one eye and a biconvex spherical surface IOL （CeeOn 911A, AMO） in the other. After 3 months, the following were investigated： best corrected visual acuity, pupil diameter, photopic and mesopic contrast sensitivity, and wavefront aberration of the whole eye （ocular）, cornea, and internal plane. Results The differences in the best corrected visual acuity and pupil diameter between the two groups were not statistically significant. Negative 4th-order spherical aberration （Z4^0） was found in the Tecnis group, whereas positive Z4^0 found in the CeeOn group for the internal and ocular plane. Statistically significant differences were found at the ocular higher-aberrations between the two IOLs. Contrast sensitivity testing showed significantly better results in the Tecnis group at visual angles higher than 1.0 degree under photopic conditions and at visual angles higher than 1.6 degree under mesopic conditions both without glare and with glare in comparison with the CeeOn group. Conclusions The Tecnis Z9001 IOL with a modified prolate anterior surface produces negative spherical aberration and consequently reduces the higher-order aberrations in pseudophakic eyes. This leads to enhanced contrast sensitivity and improved functional vision compared to conventional spherical IOLs.