showed a beneficial effect of F6H8 by immediately fusing with the precorneal tear film and compensating for surface irregularities. Other works showed high precision and excellent repeatability of the WASCA aberrometer when assessing HOA [ 26, 27]. Three consecutive scans were acquired under mesopic lighting conditions for the right and then the left eye, by a single optometrist according to a standardized operating procedure, including standardized oral instructions for each patient. Lipid phase product to protect against evaporation and dry eyes caused by screen work (PC, smartphone), air conditioning or drafts. As buffer phosphate-containing compounds are often used, which, on an irritated ocular surface can lead to damage and thus visual impairment.

The purpose of this prospective, controlled clinical study was to evaluate the effect of a non-aqueous liquid, perfluorohexyloctane (F6H8; Evotears®), on HOA after four weeks of application in otherwise healthy subjects. Previous studies have shown that a uniform reduction of the tear film seems to have little influence on the image quality [ 6]. Eyelids are the mobile skin folds that cover the anterior part of the eye and whose main function is to protect the ocular blood cell.This causes a progressive deterioration of the cells of the epithelium of the retina which causes blurred central vision. Thus, each blink leads to the renewal of the lipid layer, which prevents premature evaporation and destabilisation of the tear.

In Europe there are 4 million people with EMD and in Spain there are approximately 300,000 patients. We demonstrated higher repeatability of HOA measurements after application of F6H8 than in untreated eyes, which is in accordance with the results of previously mentioned works. For the first one hundred eyes, we derived Limits of Repeatability (LoR) and bias, or mean difference, values for measured aberrometric and manifest refraction spherical equivalent values [ 14]. In addition, a drop has a volume of only about 10 μl and therefore up to 280 drops per 3 ml content can be dispensed from one bottle of EvoTears ®. EvoTears ® OMEGA is lipophilic, thanks to the innovative substance perfluorohexyloctane, and yet has the same refractive index as the tear.

The negative effect of HOA increase on visual quality after use of AT has been shown previously [ 34]. Influence of perfluorohexyloctane eye drops on tear film thickness in patients with mild to moderate dry eye disease: a randomized controlled clinical trial. Age-associated AMD or Macular Degeneration is a degenerative eye disease that affects the central area of the retina or macula.