Impact of defocus and high-order aberrations on light distortion measurements

• Autor(a) principal: Sousa, Ana Isabel Carvalho Amorim
• Data de Publicação: 2019
• Outros Autores: Araújo, Rute Juliana Ferreira Macedo, Fernandes, Paulo RB, Queirós, A., González-Méijome, José Manuel
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/1822/57813
• topic: Science & Technology

Purpose. To evaluate the impact of different levels of positive and negative defocus on light disturbance (LD) measures and to understand how high-order aberrations (HOAs) and topographic quality parameters may influence the perception of photic phenomena. Methods. Thirty young healthy subjects (21 females and 9 males) attended this cross-sectional study. LD was evaluated with the light distortion analyzer (LDA) in natural accommodative and cycloplegic conditions with positive and negative induced defocus of 1.00D. HOAs were taken for a natural mesopic (without cycloplegia) and for fixed 5mm (with cycloplegia) pupil size. The impact of corneal morphological parameters (SAI, SRI, and Q-value) in LD was also investigated. Results. Positive and negative induced defocus of 1.00D significantly increased the size of LD (p<0.010, Wilcoxon signed rank test) but not its irregularity index. Spherical-like HOAs were associated with the size of LD, while coma-like and total-like HOAs were associated with LD irregularity. Our results showed that SRI was significantly correlated with the size of the disturbance area (r=0.519, p=0.003, Spearman correlation) and SAI with both size (r=0.502, p=0.005, Spearman correlation) and irregularity (r=0.371, p=0.044, Spearman correlation). However, no correlation between the Q-value and LD parameters was found. Conclusions. The uncorrected positive and negative refractive errors might increase the size of the LD, such as the spherical-like HOAs, SAI, and SRI, instead of asphericity. Coma-like and total-like HOAs and SAI may influence the perception of irregularities in the LD shape. These results might have an impact on postrefractive surgery visual performance that should be investigated.