ANISOMETROPIA AND PRESBYOPIA - PRESCRIBIN G PROGRESSIVE LENSES, A NEWAPPROACH

Objective of the study To show that anisometropia does not absolutely preclude the prescription of progressive lenses. Materials and methods Forty-one anisometropes and presbyopes were selected for a prolonged trial of visual correction using progressive lenses. The congenital or acquired type of their anisometriopia and its particular form were al so studied, Each patient was submitted to a protocol comprising of a s eries of ophthalmologic and orthoptic tests so as to evaluate the pati ent's subjective far and near refraction, with measurement of phorias and of horizontal and vertical ductions, visual acuity, and the qualit y of binocular vision while looking in different directions. A prelimi nary trial of correction in actual situation was done in older to chec k fusion in near vision, The entire range of tests was repeated two mo nths after the patient was provided with the lenses. The tolerance for progressive lenses during redifferent activities of daily life was ev aluated after the second and the sixth months. Results Seven patients presenting an associated strabismus were not provided with the lenses because the initial pre-lens trial revealed a total inability to read within the near-vision zone. Among the 34 patients provided with the l enses, 21 constantly, wore their progressive lenses and said that they were satisfied, 6 wore their progressive lenses during daily activiti es but preferred to use their unifocal lenses for prolonged reading, a nd 7 abandoned their progressive lenses because they could not tolerat e them. Association with a strabismus is not synonymous with an initia l impossibility or with abandonment because of the 27 patients who con stantly wore their progressive lenses 9 were strabismic. The best resu lts were obtained in the age range of 45 to 52 years old, for visual a cuity for > 20/40, and in cases of congenital anisometropia with inter mittent or permanent unilateral neutralization. On the other hand, pat ients presenting an acquired anisometropia, particularly postoperative , proved to be poor candidates. Conclusion Weak and strong anisometrop ia does not absolutely preclude the prescription of progressive lenses except for certain strabismic subjects with an abnormal lateral-orien ted posture.