Corneal Power Distribution and Functional Optical Zone Following Small Incision Lenticule Extraction for XXXX .

@entity1 @entity940 @entity1714
PURPOSE: To evaluate corneal power distribution using the ray tracing method (corneal power) in eyes undergoing small incision lenticule extraction (SMILE) surgery and compare the functional optical zone with two lenticular sizes. METHODS: This retrospective study evaluated 128 @entity1 who underwent SMILE for the correction of @entity1714 and @entity940 with a lenticular diameter of 6.5 mm (the 6.5-mm group) and 6.2 mm (the 6.2-mm group). The data include refraction, correction, and corneal power obtained via a Scheimpflug camera from the pupil center to 8 mm. The surgically induced changes in corneal power (  corneal power) were compared to correction and   refraction. The functional optical zone was defined as the largest ring diameter when the difference between the ring power and the pupil center power was 1.50 diopters or less. The functional optical zone was compared between two lenticular diameter groups. RESULTS: Corneal power distribution was measured by the ray tracing method. In the 6.5-mm group (n=100),   corneal power at 5 mm showed the smallest difference from   refraction and   corneal power at 0 mm exhibited the smallest difference from correction. In the 6.2-mm group (n=28),   corneal power at 2 mm displayed the lowest dissimilarity from   refraction and   corneal power at 4 mm demonstrated the lowest dissimilarity from correction. There was no significant difference between the mean postoperative functional optical zones in either group when their spherical equivalents were matched. CONCLUSIONS: Total corneal refactive power can be used in the evaluation of surgically induced changes following SMILE. A lenticular diameter of 6.2 mm should be recommended for @entity1 with @entity1714 because there is no functional difference in the optical zone.
