Copyright@ José M González Méijome | Biomed J Sci & Tech Res | BJSTR. MS.ID.006027. 29583 Research Article ISSN: 2574 -1241 Light Distortion as an Indicator of Adaptation to Multifocality after Refractive Lens Exchange (RLE) Santiago Escandón-García 1 , Filomena Ribeiro 2 , Colm McAlinden 3,4,5 and José González- Méijome 1 * 1 Clinical & Experimental Optometry Research Lab (CEORLab), Center of Physics, University of Minho, Braga, Portugal 2 Hospital da Luz, Lisboa, Portugal 3 Department of Ophthalmology, Royal Gwent Hospital, Aneurin Bevan University Health Board, Newport, UK 4 Wenzhou Medical University, Wenzhou, China 5 Eye & ENT Hospital of Fudan University, Shanghai, China *Corresponding author: José Manuel González Méijome, PhD, Center of Physics (Optometry), School of Science, University of Minho, Portugal DOI: 10.26717/BJSTR.2021.37.006027 ARTICLE INFO ABSTRACT Purpose: To evaluate short-term changes in visual function and dysphotopsia under low illumination conditions after refractive lens exchange (RLE) in presbyopic patients implanted with multifocal intraocular lenses (IOLs). Methods: Thirty eyes of 17 patients underwent presbyopic RLE with multifocal IOL implantation (13 bilaterally). Distance visual acuity was measured under photopic conditions and contrast sensitivity was measured without and with the presence of glare (28 lux) in dim illumination. LD was evaluated with a prototype device. Subjective quality of vision was also assessed with the Quality of Vision (QoV) questionnaire at three visits, before surgery, 1 and 3 months following implantation. QoV questionnaire scores symptoms across 3 subscales: frequency, severity and bothersome. Results: Defocus curves at 1 month and 3 months revealed that no clinical or statistically significant difference was present in any vergence. The CS function under photopic and mesopic conditions with glare showed statistically significant improvement for the frequency at 3.00 cycles per degree (p=0.032). LD under monocular conditions showed a significant increase from baseline to 1 month and this change was statistically significant (p=0.039). A binocular summation effect was observed that reduced the light disturbance index (LDI) parameter. Optical phenomena in terms of frequency and severity worsen 1 month post-operatively but return to baseline at 3 months. However, bothersome of symptoms remained the same at 1 month post-operatively and decreased at 3 months post-operatively (p=0.04). Conclusions: Despite the persistence of light disturbances in the medium term, RLE patients improve their contrast sensitivity and refer less bothersome visual complains. Received: July 19, 2021 Published: July 28, 2021 Citation: Santiago Escandón-García, Filomena Ribeiro, Colm McAlinden and José González-Méijome. Light Distortion as an Indicator of Adaptation to Multi- focality after Refractive Lens Exchange (RLE). Biomed J Sci & Tech Res 37(4)- 2021. BJSTR. MS.ID.006027. Keywords: Refractive Lens Exchange; Multifocal IOLs; Presbyopia; Dysphotop- sias Abbreviations: IOLs: Multifocal Intraocu- lar Lenses; RLE: Refractive Lens Exchange; CSF: Contrast Sensitivity Function; VA: Visual Acuity; cpd: Cycles Per Degree; QoV: Quality of Vision Questionnaire; LD: Light Distortion; LDI: Light Disturbance Index; ANOVA: Analysis of Variance; NEI- RQL: National Eye Institute Refractive Er- ror Quality of Life Instrument; FCT: Foun- dation for Science and Technology Introduction Multifocal intraocular lenses (IOLs) allow spectacle independence rates over 80% [1] and the optics of these devices challenge all the physiology of vision due to the distribution of light over the retina. It requires the activation of neuroprocessing, the brain to have the ability to adapt to changes, and to subsequently adjust to the neurophysiology changes that are induced in the quality of retinal image. For this reason, neuroprocessing is the main challenge for multifocal IOLs [2]. Refractive lens exchange (RLE) can be used to correct ametropia and/or presbyopia in subjects over 40 years [3]. The term PRELEX (Presbyopic Lens Exchange) is often used to define implantation of multifocal intraocular lens with RLE [4-7]. The physical features of multifocal IOLs differ from the original human lens, so each patient needs certain amount of time to adapt to use this correction (neuroadaptation) which may vary among patients [1,8]. Higher incidence of visual