Abstract
Purpose.:
To study eye movements in a large group of children after the removal of unilateral infantile cataract, and to compare fixation instabilities between treatment groups with or without IOL implantation.
Methods.:
The Infant Aphakia Treatment Study (IATS) is a randomized, multicenter clinical trial comparing IOL to contact lens (CL) treatment with a unilateral infantile cataract in participants who underwent cataract surgery at 1 to 6 months of age. At age 4.5 years, eye movements were recorded in 103 participants, using a high-speed video camera while the child performed a fixation task. The recordings were inspected by masked readers for the presence of fixation instabilities (nystagmus and saccadic oscillations).
Results.:
Overall, fixation instabilities were observed in 50 (60%) of 83 children who had evaluable recordings, with no differences between treatment groups (27 [64%] of 42 in the IOL group, 23 [56%] of 41 in the CL group; P = 0.51). Nystagmus was seen in 38% and saccadic oscillations in 31%, with no differences between treatment groups (P > 0.33). Children without a fixation instability had better visual acuity (P = 0.04).
Conclusions.:
Nystagmus and saccadic oscillations are well-known consequences of infantile cataracts, presumably the result of visual deprivation during the critical period of visual development. After early cataract extraction, successful optical correction may reduce further form deprivation and minimize the incidence of these fixation instabilities. In this study, no differences in the presence of fixation instabilities were found between the two treatment strategies (CL or IOL) for optical correction after cataract removal. (ClinicalTrials.gov number, NCT00212134.)
Infants in the CL group underwent an extracapsular lensectomy, posterior capsulotomy, and anterior vitrectomy through the capsulotomy, whereas those in the IOL group initially had the lens aspirated followed by the implantation of an AcrySof SN60AT into the capsular bag. In the event that both haptics could not be implanted into the capsular bag, a different IOL (AcrySof MA60AT; Alcon Laboratories) was implanted into the ciliary sulcus after subtracting 1.0 diopter (D) from the calculated IOL power. Intraocular lens power targeted an 8-D undercorrection for infants 4 to 6 weeks of age and a 6-D undercorrection for infants older than 6 weeks. Following IOL placement, a posterior capsulectomy and an anterior vitrectomy were performed through the pars plana/plicata.
Within a week after cataract surgery, infants in the CL group were fitted with a Silsoft (Bausch & Lomb, Rochester, NY, USA) or a rigid gas-permeable CL (per discretion of the investigator or the site-based contact lens specialist) with a 2.0-D overcorrection to provide a near point focus. For patients in the IOL group, spectacles were prescribed at or before the 1-month postoperative visit and/or at any later visit when one of the following conditions existed in the treated eye: hyperopia of more than 1.0 D, myopia of more than 3.0 D, or astigmatism of more than 1.5 D. The overall aim was to overcorrect the refractive error by 2.0 D to achieve a near point correction until the child was 2 years old. At that time, distance correction glasses with bifocals were prescribed for all patients, and patients were asked to wear them at all times while awake.
Starting the second postoperative week, parents were instructed to have their child wear an adhesive occlusive patch over the unoperated eye for x hours/day (where x equals the child's age in months), thus gradually increasing the amount of prescribed daily patching, until age 8 months. Thereafter, patching was prescribed for one-half of waking hours.
Scott R. Lambert, MD (Study Chair); Lindreth DuBois, MEd, MMSc (National Coordinator)
Contact Lens Committee: Buddy Russell, COMT; Michael Ward, MMSc
Data and Safety Monitoring Committee: Robert Hardy, PHD (Chair); Eileen Birch, PhD; Ken Cheng, MD; Richard Hertle, MD; Craig Kollman, PhD; Marshalyn Yeargin-Allsopp, MD (resigned); Cyd McDowell; Donald F. Everett, MA (ex officio)
Data Coordinating Center (Emory University): Michael Lynn, MS (Director), Betsy Bridgman, BS; Marianne Celano, PhD; Julia Cleveland, MSPH; George Cotsonis, MS; Carey Drews-Botsch, PhD; Nana Freret, MSN; Lu Lu, MS; Seegar Swanson; Thandeka Tutu-Gxashe, MPH
Eye Movement Reading Center (University of Alabama, Birmingham and Retina Foundation of the Southwest, Dallas, TX): Claudio Busettini, PhD, Samuel Hayley, Joost Felius, PhD
Medical Safety Monitor: Allen Beck, MD
Program Office (National Eye Institute): Donald F. Everett, MA
Steering Committee: Scott R. Lambert, MD; Edward G. Buckley, MD; David A. Plager, MD; M. Edward Wilson, MD; Michael Lynn, MS; Lindreth DuBois, Med MMSc; Carolyn Drews-Botsch, PhD; E. Eugenie Hartmann, PhD; Donald F. Everett, MA
Vision and Developmental Testing Center (University of Alabama, Birmingham): E. Eugenie Hartmann, PhD (Director); Anna K. Carrigan, MPH; Clara Edwards
Participating Clinical Centers (in order by the number of patients enrolled):
Medical University of South Carolina, Charleston, South Carolina (14): M. Edward Wilson, MD; Margaret Bozic, CCRC, COA
Harvard University, Boston, Massachusetts (14): Deborah K. Vanderveen, MD; Theresa A. Mansfield, RN; Kathryn Bisceglia Miller, OD
University of Minnesota, Minneapolis, Minnesota (13): Stephen P. Christiansen, MD; Erick D. Bothun, MD; Ann Holleschau, BA; Jason Jedlicka, OD; Patricia Winters, OD; Jacob Lang, OD
Cleveland Clinic, Cleveland, Ohio (10): Elias I. Traboulsi, MD; Susan Crowe, BS, COT; Heather Hasley Cimino, OD
Baylor College of Medicine, Houston, Texas (10): Kimberly G. Yen, MD; Maria Castanes, MPH; Alma Sanchez, COA; Shirley York
Emory University, Atlanta, Georgia (9): Scott R. Lambert, MD; Amy K. Hutchinson, MD; Lindreth Dubois, Med, MMSc; Rachel Robb, MMSc; Marla J. Shainberg, CO
Oregon Health and Science University, Portland, Oregon (9): David T Wheeler, MD; Ann U. Stout, MD; Paula Rauch, OT, CRC; Kimberly Beaudet, CO, COMT; Pam Berg, CO, COMT
Duke University, Durham, North Carolina (8): Edward G. Buckley, MD; Sharon F. Freedman, MD; Lois Duncan, BS; B.W. Phillips, FCLSA; John T. Petrowski, OD
Vanderbilt University, Nashville, Tennessee (8): David Morrison, MD; Sandy Owings COA, CCRP; Ron Biernacki, CO, COMT; Christine Franklin, COT
Indiana University, Indianapolis, Indiana (7): David A. Plager, MD; Daniel E. Neely, MD; Michele Whitaker, COT; Donna Bates, COA; Dana Donaldson, OD
Miami Children's Hospital, Miami, Florida (6): Stacey Kruger, MD; Charlotte Tibi, CO; Susan Vega
University of Texas Southwestern, Dallas, Texas (6): David R. Weakley, MD; David R. Stager Jr, MD; Joost Felius, PhD; Clare Dias, CO; Debra L. Sager; Todd Brantley, OD
Case Western Reserve, Cleveland, Ohio (1): Faruk Orge, MD