Abstract
Purpose :
To investigate which amblyopic children are at risk for visual acuity (VA) deterioration.
Methods :
In a previous RCT (2001, N=303; Loudon et al.) we investigated risk factors for non-compliance with occlusion therapy and determined whether compliance can be improved in all newly diagnosed children in The Hague. Compliance was measured electronically with the Occlusion Dose Monitor (ODM). Treatment continued until no further improvement in VA was measured. Between December 2015 – July 2017 these patients were re-examined with a full orthoptic examination including the Landolt-C chart 17.2’ for VA at distance and the Radner chart for reading VA. Examinations were carried out by the research orthoptist through domiciliary visits and at the out-patient clinic Haaglanden MC, Westeinde, The Hague. VA deterioration was defined as a decrease of ≥0.2 logMAR lines between the current VA and the last VA measured during the RCT 15 years ago.
Results :
Fifteen years after treatment, we were able to contact 208 (69%) subjects; 59 (19%) refused and 17 (6%) were excluded. We were able to include 132 subjects. When comparing the current VA of the amblyopic eye with the VA directly after treatment, there were five (4%) subjects, who had a VA decrease of ≥0.2 logMAR. Their mean age at start of occlusion was 4.1 (SD±0.4) years and current age was 16.6 (SD±1.1) years. Mean VA of the amblyopic eye at start of treatment was 0.83 (SD±0.41) logMAR, at the end of treatment 0.29 (SD±0.16) and current VA of the amblyopic eye was 0.76 (SD±0.15) logMAR. Current mean reading acuity was 1.39 (SD±0.83) logMAR. All of them had microstrabismus and eccentric fixation. Compliance with treatment at the time varied from 0%-99%. Current VA of the fellow eye in all five subjects was ≤0 logMAR.
Conclusions :
In our cohort of 132 treated amblyopes 4% had VA deterioration of ≥0.2 logMAR fifteen years after treatment. The only patients, who showed this deterioration had a combination of microstrabismus, eccentric fixation and low VA (i.e. equal or worse than 0.3 logMAR) at start of therapy. It may be worthwhile for this type of amblyopes, to extend the treatment until the end of the sensitive period.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.