The impact of error of refraction and retinal nerve fiber layer thickness on cognitive functions in adults with bilateral myopia

Abstract

Objective

Myopia is considered one of the main causes of visual impairment with increased prevalence. The main objective of this study was to evaluate and characterize cognitive impairment in adult patients with bilateral myopia, in relation to retinal nerve fiber layer (RNFL) thickness.

Methods

Forty patients with bilateral myopia aged 18–40 years, and 40 age- and gender-matched healthy controls were included in the study. For all subjects, cognitive functions were assessed by Paced Auditory Serial Addition Test (PASAT) and Paired Associate Learning test (PALT). Optical coherence tomography (OCT) was done for all included patients and controls.

Results

Among the myopic group, 15 patients had mild myopia, 8 patients had moderate myopia and 17 patients had high myopia. There were significant differences between patients and control groups in terms of cognitive performance and RNFL thickness. There was a significant correlation between the scores of cognitive tests and error of refraction and RNFL thickness.

Conclusion

Adults with bilateral myopia have cognitive impairment, regarding information processing speed and episodic memory. Cognitive impairment is associated with retinal thinning and a higher degree of myopia.

Keywords:

• Myopia
• optical coherence tomography
• cognition
• episodic memory

Authors’ contribution

MH participated in study design, collection and analysis of data and helped to draft manuscript. SI participated in study design, ophthalmological assessment, and helped to draft manuscript. AT participated in study design, ophthalmological assessment and helped to draft manuscript. RM participated in study design, collection and analysis of data and helped to draft manuscript. All authors read and approved the final manuscript with agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Ethics approval

A written informed consent was obtained from each participant in this study. The study was conducted in accordance with the Declaration of Helsinki. The study was approved by local ethical committee in Faculty of medicine, Beni-Suef University.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Availability of data and materials

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request with permission of Faculty of Medicine, Beni-Suef University, Egypt.