The impact of vision screening in preschool children on visual function in the Swedish adult population

BACKGROUND: Amblyopia is the most common monocular visual impairment in Scandinavia. A visual screening programme for preschool children was introduced in Sweden in the 1970s to reduce the prevalence of amblyopia. The purpose of this study was to investigate the impact of this visual screening programme in adult men recruited to the armed forces in Sweden.METHODS: The prevalence of amblyopia was compared in recruits born in 1956-1957 (n = 1500), before the introduction of the visual screening programme (unscreened), and those born in 1977-1979 (n = 2626), after the visual screening programme was introduced (screened). Amblyopia was defined as bilateral, if the bilateral best corrected visual acuity (BCVA) was <0.5 (20/40), and unilateral if there was a ≥2-line interocular difference and BCVA was <0.625 (20/32) in the worse eye. Subgroup analysis was performed on recruits with hyperopia, myopia and anisometropia.RESULTS: The prevalence of amblyopia was significantly lower after the introduction of the Swedish visual screening programme. Forty-seven (3.3%) of the unscreened and 23 (0.9%) of the screened recruits had unilateral amblyopia (p < 0.0001, OR = 0.26 (95%CI 0.16-0.43)). The risk for developing amblyopia was markedly reduced by screening in recruits with hyperopia (≥2D) (p < 0.0001 and OR 0.034 (95% CI 0.003-0.207)) and anisometropia (≥1.5D interocular difference) (p < 0.01 and OR 0.20 (95% CI 0.08-0.66)). Only a few recruits with myopia had amblyopia.CONCLUSIONS: The results demonstrate the value of the Swedish visual screening programme for preschool children in preventing amblyopia. Anisometropia or high hyperopic refractive errors can be identified by screening and corrected to prevent amblyopia

The success of unilateral surgery for constant and intermittent exotropia and factors affecting it in a large scandinavian case series

Purpose: To compare the results of surgery for constant and intermittent exotropia, to determine factors affecting surgical success, and to evaluate the effect of horizontal rectus muscle surgery on distance-near incomitance. Methods: In this retrospective study of 291 Scandinavian patients, inclusion criteria were surgery for constant (n = 101) or intermittent (n = 190) exotropia with no vertical deviation, no previous strabismus surgery, and available postoperative follow-up data. Medical records of patients (age: 3 to 85 years) undergoing surgery were reviewed. Surgical success was defined as postoperative esodeviation of less than 5 prism diopters (PD) to exodeviation of 10 PD or less. Results: Surgical success was 70% in constant exotropia and 80% in intermittent exotropia (P > .05). At follow-up 1.5 years after surgery, a significant drift was found in intermittent exotropia (P .05). The surgical success rate increased with decreasing preoperative angle (P < .05). Resection of the medial rectus muscle had a greater effect on the near deviation, whereas recession of the lateral rectus muscle had a greater effect on the distance deviation (P < .05). Conclusions: Surgical success was equally good in constant and intermittent exotropia, but better long-term stability was observed following surgery for constant exotropia. The only factor affecting surgical success was the preoperative deviation, with smaller deviations having a better outcome. A distance-near incomitance may be an important consideration in choosing the magnitude of medial versus lateral rectus muscle surgery

Comparison of a new digital KM screen test with conventional Hess and Lees screen tests in the mapping of ocular deviations

PURPOSE: To evaluate the digital KM screen computerized ocular motility test and to compare it with conventional nondigital techniques using the Hess and Lees screens.METHODS: Patients with known ocular deviations and a visual acuity of at least 20/100 underwent testing using the digital KM screen and the Hess and Lees screen tests. The examination duration, the subjectively perceived difficulty, and the patient's method of choice were compared for the three tests. The accuracy of test results was compared using Bland-Altman plots between testing methods.RESULTS: A total of 19 patients were included. Examination with the digital KM screen test was less time-consuming than tests with the Hess and Lees screens (P < 0.001 and P = 0.003, resp., compared with the digital KM screen). Patients found the test with the digital KM screen easier to perform than the Lees screen test (P = 0.009) but of similar difficulty to the Hess screen test (P = 0.203). The majority of the patients (83%) preferred the digital KM screen test to both of the other screen methods (P = 0.008). Bland-Altman plots showed that the results obtained with all three tests were similar.CONCLUSIONS: The digital KM screen is accurate and time saving and provides similar results to Lees and Hess screen testing. It also has the advantage of a digital data analysis and registration