The authors aimed to review cases with divergence insufficiency esotropia in 12 young adults associated with excessive near work. Patients were aged 28.17 ±4.06 years and had normal external, anterior / posterior segment examinations and no neurological signs. Ten had constant horizontal diplopia and two had intermittent horizontal diplopia at distance fixation. Esotropia onset preceded hospital presentation by 4.75 ±1.48 months. The distance angle was greater than the near angle by at least 10PD. There was no gaze limitations and no high myopia. Best corrected visual acuity was 20/20 for all in both eyes. Accommodative convergence to accommodation (AC/A) ratio was low at a mean of 2.12 ±0.23. Fusional divergence amplitudes were reduced: 4.92 ±2.35D break and 2.50 ±1.76D recovery at distance, 12.50 ±2.93D break and 9.75 ±2.65D recovery at near. The average time of near work per day was 6.51 ±1.19 hours. The median distance angle was 27.5PD (18-35) and for near was 15PD (8-20). Reduction of near work to less than one hour for three months resulted in all patients having a significant reduction in angle: 20PD (10-25) distance and eight (2-13) for near. One patient regained orthophoria and 11 results with prisms (n=6) or surgery (n=5). The authors ruled out an accommodative element, uncorrected refractive error and neurological causes of divergence insufficiency. They suggest the excessive near work might influence the development divergence insufficiency esotropia because of a larger accommodative effort with associated increased convergence tonus to achieve clear binocular vision. Treatment is to refrain from excessive near work and improve fusional vergence.
Distance esotropia due to excessive near work
Reviewed by Fiona Rowe
Young patients with divergence insufficiency related to excessive near work.
Fiona Rowe (Prof)
Institute of Population Health, University of Liverpool, UK.View Full Profile