A randomized controlled trial comparing soft contact lens and rigid gas-permeable lens wearing in infantile nystagmus.

OBJECTIVE: To perform the first randomized controlled trial comparing soft contact lens (SCL) with rigid gas-permeable lens (RGPL) wearing in infantile nystagmus (IN), using spectacle wear as a baseline. DESIGN: Randomized, controlled cross-over trial with an intention-to-treat design. PARTICIPANTS AND CONTROLS: A total of 24 participants with IN (12 idiopathic, 12 with albinism). METHODS: Participants were randomized into 1 of 2 treatment arms receiving the following sequence of treatments (2-3 weeks for each treatment): (A) spectacles, SCL, RGPL, and spectacle wear; or (B) spectacles, RGPL, SCL, and spectacle wear. MAIN OUTCOME MEASURES: The main outcome measure was mean intensity of nystagmus at the null region viewing at 1.2 m. Secondary outcome measures included the same measure at 0.4 m viewing and across the horizontal meridian (measured over a ±30° range at 3° intervals) for distance and near. The nystagmus foveation characteristics were similarly assessed over ±30° and at the null region at 1.2 m and 0.4 m viewing. Visual outcome measures included best-corrected visual acuity (BCVA) at 4 m and 0.4 m, gaze-dependent visual acuity (GDVA) (i.e., visual acuity when maintaining gaze angles over a ±30° range at 10° intervals) at 4 m, and reading performance at 0.4 m derived from the Radner reading chart. RESULTS: There were no significant differences between SCL and RGPL wearing for any nystagmus characteristics or compared with spectacle wearing. The BCVA, reading acuity, and critical print size were significantly worse for SCL wearing compared with RGPL and baseline spectacle wear (P<0.05), although mean differences were less than 1 logarithm of the minimum angle of resolution (logMAR) line. CONCLUSIONS: Nystagmus was not significantly different during SCL and RGPL wearing in IN, and contact lens wearing does not significantly reduce nystagmus compared with baseline spectacle wearing. The wearing of SCL leads to a small but statistically significant deterioration in visual function compared with both RGPL and spectacle wearing at baseline, although mean effect sizes were not clinically relevant.

Barriers to spectacle use in Tanzanian secondary school students.

PURPOSE: Screening school students for refractive errors is a component of many primary eye care programs. In 2004 a trial of two approaches of spectacle-delivery to Tanzanian secondary school students found that only one third of students were using their spectacles at three months. Barriers to spectacle use were investigated using questionnaires and focus group discussions. METHODS: At the three months follow-up survey a questionnaire explored satisfaction with spectacles and the attitudes of trial participants (median age 15 years). Attitudes and reactions of friends, teachers and families were also explored. Students also discussed their experience with spectacle use and reasons for non-use in 8 focus groups divided by intervention, sex and spectacle use. RESULTS: In general, students seemed happy with the appearance of their spectacles and the beneficial impact on their vision. Peer pressure and parental concerns about safety of spectacle use, cost of purchasing spectacles and difficulties in accessing good local optical services were identified as the main barriers. Students criticized prescribing practices of local opticians and favored alternative and traditional treatments for visual impairment. CONCLUSION: To increase the effectiveness of school vision screening in Tanzania, barriers such as peer pressure or concerns about safety need to be addressed, in addition to provision of affordable, good quality spectacles. Barriers to spectacle use in children are likely to exist in all populations, but may vary in their nature and importance and therefore should be investigated in existing and new screening programs.