Bilateral monocular diplopia associated with lid position during near work.

PURPOSE

To describe a common pattern of topographic changes and clinical signs of six patients presenting with a complaint of monocular diplopia after reading and to investigate the cause of this topographic disturbance.

PATIENT POPULATION

Subject group of six patients with monocular diplopia complaints after reading and 20 patients without such complaints. Examinations performed before and after a reading period of 30 min: videokeratoscopic examination, red reflex examination, position of the lids in primary gaze and in reading position.

DATA ANALYSIS

inspection of keratoscopic rings, qualitative analysis of topography maps, comparison of SAI and SRI of control and subject groups before and after reading, comparison of lid position of control and subject group.

RESULTS

Half of the subject group and none of the control 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) corresponding to the development of a focal distortion in the entrance pupil of the videokeratoscopic image. Each subject developed a horizontal band 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 down gaze was narrower in the subject group compared with the control group (p = 0.001).

CONCLUSIONS

Some individuals may develop monocular diplopia after reading. We hypothesize that during near work these corneal topographic alterations occur primarily related to the position of the lids and tear film interaction with the corneal surface.