EVALUATION OF A NEW ALGORITHM FOR THE ASSESSMENT OF REFRACTIVE ERRORS COMPARED TO CONVENTIONAL CYCLOPLEGIA

Refractive disorders, including myopia, are constantly evolving and could affect half of the world's population by 2050. The increase in the number of refractive surgeries requires reliable, rapid and reproducible methods of evaluation of these defects.

This is a comparative, monocentric, prospective study carried out in the ophthalmology department of the University Hospital of Brest, between January 2021 and May 2022 on a total of 300 patients operated on for corneal refractive surgery.

The primary outcome was a comparison of the spherical equivalent and the vector components of the Jackson cross cylinder ( J0 and J45). These data were derived from the automated "Smart Brouillard" algorithm of the ESSILOR® VR-800, the manifest refraction and the cycloplegic refraction (cyclopentolate). 

The Smart Brouillard overestimates the spherical equivalent by -0.25D (p< 0.01) compared to cycloplegia, while the manifest refraction overestimates by -0.36D (p< 0.01). In the myopic subgroup, the difference (-0.11D, p<0.01) is smaller than in the hyperopic subgroup (-0.38D, p<0.01). Concerning astigmatism, the cylindrical difference was 0.25D lower whatever the degree of astigmatism and this in all groups. 

The Smart Brouillard of the ESSILOR® VR-800 over evaluates myopia minimally compared to cycloplegia and gives a more accurate result than the conventional fog technique. The clinical difference is acceptable in the myopic patient and is less than one lens step on a conventional phoropter. Astigmatism is correctly evaluated, whatever its degree. It is useful in a population of 18-40 year olds as part of a pre-refractive surgery assessment.