OCULAR GROWTH IN INFANT APHAKIA - BILATERAL VERSUS UNILATERAL CONGENITAL CATARACTS

In a prospective study the changes in the ocular axial lengths and in the overall refractions were examined in cases of unilateral and bilat eral congenital cataract requiring surgery during the first year of li fe. Measurements were taken on 18 children with unilateral and on 20 c hildren with bilateral congenital cataract at the time of surgery and up to eight years postoperatively. Surgery was performed via a pars pl ana/plicata approach, and all infants were fitted with contact lenses. In cases of unilateral cataract, the ocular axial length tended to be superior to the age-matched values already prior to surgery. After fo ur to eight years, one third of the eyes were clearly above normal. In cases of bilateral cataract, the axial lengths were reduced at the ag e of surgery in the majority of cases, and particularly in eyes that r equired surgery during the first six months of life. The curvatures of the contact lenses tended to remain unchanged in bilateral cataract, and decreased by about 0.7 mm in unilateral cases. This also reflects the high degree of microphthalmia in bilateral cases. After four to ei ght years, the degree of microphthalmia had usually increased. The ove rall refraction decreased significantly in unilateral and bilateral ca taract during the first four years of life. The mean values were highe r in bilateral than in unilateral cataract at all ages. The mean decre ase was 15 diopters in unilateral cataract (SD +/- 5.5 dpt), and 10 di opters in bilateral cataract (SD +/- 6 dpt). When correlating the age- matched differences in the ocular axial lengths at the time of surgery with the overall refractions after four to eight years, a good correl ation was found in the unilateral cases (eight eyes), and a poor corre lation in the bilateral cases (24 eyes). The data indicate that intrao cular implants should not be used in bilateral cataract requiring surg ery during the first year of life as long as there is no possibility t o change their refraction while in place. In unilateral cases, a relat ively accurate prediction appears possible in a small number of eight eyes. However, an additional important correction with glasses would b e needed before reaching the final refraction resulting in a high degr ee of aniseiconia, and eliminating the chances for binocular vision th at are small anyway. Furthermore, data from other authors would indica te that the change in refraction may be much more important than expec ted when using intraocular implants in unilateral congenital cataract requiring surgery during the first year of life. By the use of contact lenses, good to excellent visual functions can be achieved.