BILATERAL MONOCULAR DIPLOPIA ASSOCIATED WITH LID POSITION DURING NEARWORK

Purpose, To describe a common pattern of topographic changes and clini cal signs of six patients presenting with a complaint of monocular dip lopia after reading and to investigate the cause of this topographic d isturbance. Methods, Patient population: Subject group of six patients with monocular diplopia complaints after reading and 20 patients with out such complaints. Examinations performed before and after a reading period of 30 min: videokeratoscopic examination, red reflex examinati on, position of the lids in primary gaze and in reading position. Data analysis: inspection of keratoscopic rings, qualitative analysis of t opography maps, comparison of SAI and SRI of control and subject group s before and after reading, comparison of lid position of control and subject group. Results, Half of the subject group and none of the cont rol group developed subtle ring distortions of keratoscopic rings. SAI and SRI values increased significantly in the subject group compared with the control group (p = 0.02 and p < 0.001, respectively) correspo nding to the development of a focal distortion in the entrance pupil o f the videokeratoscopic image. Each subject developed a horizontal ban d on red reflex located at the superior, middle, or inferior aspect of the pupil after near work. Two controls developed faint bands in the red reflex outside the entrance pupil. The interpalpebral fissure in d own gaze was narrower in the subject group compared with the control g roup (p = 0.001). Conclusions. Some individuals may develop monocular diplopia after reading. We hypothesize that during near work these cor neal topographic alterations occur primarily related to the position o f the lids and tear film interaction with the corneal surface.