Evaluation of alignment of spectacle lenses using a digital camera

Purpose : To report the state of alignment of spectacle lenses using a digital still camera. Cases and Method : This study was made on 78 patients who habitually used spectacles to correct refractive errors. The series comprised 41 males and 37 females. Their ages ranged from 4 to 85 years, average 29 years. They were asked to fixate on a still camera placed 50 cm away. Deviation of spectacle lenses from their ideal position were calculated from corneal reflex and markers showing center of the lens. Results : The center of spectacle lens deviated downwards by 4.0±3.6 mm in the right eye and by 3.8±3.5 mm in the left. Distance between lens centers was larger from the interpupillary distance by 1.6±2.0 mm. Conclusion : There are several cases of misalignment between optical axis of the eye and center of the lens. Clinical evaluation of this feature is necessary to provide proper correction of refraction and ease of wearing to the patient.