The Effect of Initial Visual Acuity on Visual Prognosis in Low Vision Aid and Rehabilitation Cases

Purpose: To analyze the initial visual acuities of cases referred to our clinic due to low vision and the effect on visual prognosis. Materials and methods: A retrospective evaluation was carried out on 869 eyes of 464 patients who were referred to our center due to low vision between December 2010 and May 2015. Distance acuities of the patients were measured with a distant vision chart prepared for patients with low vision, and the near acuities were measured with a Jaeger near vision chart. Patients with logMAR ≥ 0.5 [snellen ≤ 20/63] visual acuity were included in the study. Cases were separated into 4 groups according to initial distant acuity and 3 groups according to the initial near acuity values. In the statistical analysis, a value of p < 0.05 was accepted as statistically significant. Results: The mean distant acuity of the cases was found to be 0.13 ± 0.11 (Snellen) (mean logMAR 0.9) and 0.55 ± 0.29 (Snellen) (mean logMAR 0.3) respectively before and after the low vision aid (LVA) examination. The mean near acuity of the cases was J 13.93 ± 4.21 (mean logMAR 0.8) and J 7.76 ± 4.51 (mean logMAR 0.4) respectively before and after the LVA. Initial distant visual acuity was logMAR > 1.3 [Snellen < 20/400] in 14%, logMAR 1.3-1.0 [snellen 20/400-20/200] in 48%, logMAR 0.7-1.0 [snellen 20/200-20/100] in 22% and logMAR < 0.7 [> snellen 20/100] in 16% of the cases. In total, it was seen that the visual acuity of 62% of the cases was at the level of “legally blind” (logMAR ≥ 1.0) [snellen ≤ 20/200]. The distant and near visual acuities before LVA were determined as the factors that had the greatest effect on the improvement of distant and near acuities of the patients. Conclusion: The visual acuity at the time of application is the primary factor affecting LVA success. In this study, the visual acuity of the cases referred to our center for LVA was evaluated as quite low, sufficient time could not be allocated to cases due to intense polyclinic conditions and patients were referred late. With earlier referral, it would be possible to enable patients to remain more self-sufficient.