Comparison of intraocular lens power calculation formulas with and without total keratometry and ray tracing in patients with previous myopic SMILE.

PURPOSE: To evaluate the prediction error (PE) variance and absolute median PE of different intraocular lens (IOL) calculation formulas including last-generation formulas such as Barrett True-K with K, Okulix and total keratometry (TK)-based calculations with Haigis, and Barrett True-K in a simulation model in post-small-incision lenticule extraction (SMILE) eyes. SETTINGS: Department of Ophthalmology, University Hospital Marburg, Marburg, Germany. DESIGN: Prospective study. METHODS: Preoperative measurements included IOL power calculation before and after SMILE surgery. The target refraction was set to be the lowest myopic refractive error in pre-SMILE eyes. The IOL power targeting at the lowest myopic refractive error in pre-SMILE eyes was selected for the post-SMILE IOL calculation of the same eye. The difference between the predicted refraction of pre- and post-SMILE eyes with the same IOL power was defined as IOL difference. The refractive change induced by SMILE was defined as the difference between preoperative and postoperative manifest refraction. RESULTS: 98 eyes from 49 patients underwent bilateral myopic SMILE. The PE variance of Okulix was not significantly different compared with Barrett True-K with TK ( P = .471). The SDs of the mean PEs were ±0.413 D (Haigis-TK), ±0.453 D (Okulix), ±0.471 D (Barrett True-K with TK), ±0.556 D (Haigis-L), and ±0.576 D (Barrett True-K with K). The mean absolute PE was 0.340 D, 0.353 D, 0.404 D, 0.511 D, and 0.715 D for Haigis-TK, Okulix, Barrett True-K with TK, Barrett True-K with K, and Haigis-L, respectively. The highest percentage of eyes within ±0.50 D was achieved by Okulix, followed by Haigis-TK, Barrett True-K with TK, Barrett True-K with K, and Haigis-L. CONCLUSIONS: Results suggest that Haigis in combination with TK, Okulix, and Barrett True-K with and without TK offer good options for accurate IOL power calculation after SMILE. Haigis-L showed a tendency for myopic shift in eyes after previous SMILE.

Five-year follow-up of corneal morphology and corneal refractive power changes after uneventful DMEK.

PURPOSE: To investigate changes of corneal thickness spatial profile (CTSP), corneal volume (CV) distribution, and total corneal refractive power (TCRP) over a course of 60 months after uneventful Descemet membrane endothelial keratoplasty (DMEK). METHODS: In our prospective, comparative study, sixty DMEK cases without intraoperative and postoperative complications and with complete 60-month follow-up were included (group 1). CTSP at corneal apex (CCT) and at 2 mm, 4 mm, 6 mm, and 8 mm rings, CV in 3 mm, 5 mm, 7 mm, and 10 mm zones, and TCRF in 2 mm, 4 mm 6 mm, and 8 mm zones were evaluated preoperatively and at 3, 6, 12, 24, and 60 months postoperatively. The 60-month results were compared to an age-matched group of uncomplicated pseudophakic eyes (group 2; n = 20). RESULTS: The CCT and CTSP at 2, 4, and 6 mm increased significantly at 60 months compared to 3-month outcomes (P < 0.001). Similarly, CV increased significantly in 3 mm, 5 mm, and 7 mm zones at 60 months compared to 3 months outcomes (P < 0.001). The TCRP showed in all zones a significant decrease at 3 months (P < 0.001) followed by a continuous and significant increase at 60 months (P < 0.001). The 60-month CCT and CTSP at 2 mm were similar to group 2 (P ≥ 0.094). CONCLUSION: Sixty months after uneventful DMEK, CT within the central 2 mm zone and CV at 3 mm zone were similar to uncomplicated pseudophakic eyes. A continuous and statistically significant increase of TCRP was observed in all measured zones after the 3-month examination.

Corneal Remodeling After Myopic SMILE Versus FS-LASIK: A Spatial Analysis of Short- and Mid-Term Corneal Thickness, Volume, and Shape Changes.

PURPOSE: To evaluate the short- and mid-term changes of corneal thickness spatial profile (CTSP), corneal volume distribution (CVD), and corneal asphericity after small-incision lenticule extraction (SMILE) for correction of myopia and astigmatism and compare the results with femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). METHOD: Thirty eyes of 18 patients who underwent SMILE were compared with a group of 30 eyes of 16 patients who underwent FS-LASIK. The groups were matched for preoperative central corneal thickness and lenticule thickness/ablation depth. Scheimpflug corneal tomography was performed preoperatively and postoperatively at 2 months and 3 years. The CTSP was evaluated on 4 concentric rings (2, 4, 6, and 8 mm). The CVD was evaluated at 3 concentric zones (3, 5, and 7 mm). Changes in the anterior and posterior asphericity at a 6-mm zone were also evaluated. RESULTS: Between the 2-month and 3-year examination, the CTSP showed a similar increase for both groups at all measured points and rings ( P ≥ 0.168). The CVD also showed a similar increase for both groups at all measured zones ( P ≥ 0.278). The anterior corneal asphericity remained stable after SMILE (2-mo Q = 0.46 ± 0.27; 3-yr Q = 0.45 ± 0.27; P = 0.711) but decreased significantly after FS-LASIK (2-mo Q = 0.52 ± 0.47; 3-yr Q = 0.47 ± 0.44; P = 0.028). Similarly, the posterior corneal asphericity remained stable after SMILE (2-mo Q = -0.11 ± 0.15; 3-yr Q = -0.11 ± 0.13; P = 0.902) but decreased significantly after FS-LASIK (2-mo Q = -0.13 ± 0.14; 3-yr Q = -0.16 ± 0.15; P = 0.034). CONCLUSIONS: CTSP and CVD between the 2-month and 3-year examination showed a similar increase after SMILE and FS-LASIK. During the postoperative course, the anterior and posterior corneal asphericity remained more stable after SMILE compared with FS-LASIK.

Fourier Analysis of Corneal Irregular Astigmatism After Small Incision Lenticule Extraction and Comparison to Femtosecond Laser-Assisted Laser In Situ Keratomileusis.

PURPOSE: Evaluation of spherical component (SC), regular astigmatism (RA), and irregular astigmatism (IA, ie, Asymmetry and Irregularities) 3 years after small incision lenticule extraction (SMILE) and comparison to femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). METHODS: Thirty-two eyes of 21 patients who underwent SMILE for myopia and astigmatism were compared with 32 eyes of 21 patients treated with FS-LASIK. Scheimpflug images were obtained preoperatively and 3 years postoperatively. Fourier analysis of keratometric-derived parameters (SC, RA, Asymmetry, and Irregularities) of the anterior, posterior, and total cornea were evaluated at 4 concentric rings (ring 1, 2 mm diameter; ring 2, 4 mm; ring 3, 6 mm; ring 4, 8 mm) and over the entire 8-mm zone. RESULTS: After FS-LASIK, over the 8-mm zone, the RA and IA of the anterior cornea increased significantly (P ≤ 0.002), whereas SMILE induced an insignificant increase in RA and Asymmetry (P ≥ 0.276) and a decrease in Irregularities (P = 0.770). At the 8-mm zone of the posterior cornea, the Irregularities increased significantly (P = 0.027) after FS-LASIK, whereas SMILE induced no significant changes in the examined variables (P ≥ 0.347). RA and IA of the total cornea increased significantly after FS-LASIK (P ≤ 0.001), whereas SMILE induced an insignificant increase in RA and Asymmetry (P ≥ 0.092) and a significant decrease in Irregularities (P < 0.001). FS-LASIK induced a greater decrease in SC of the total cornea at ring 4 (P = 0.009). CONCLUSIONS: FS-LASIK resulted in a greater increase in RA and Irregularities and greater flattening of the midperiphery of the anterior and total cornea compared with SMILE. The posterior cornea remained unaffected after SMILE, whereas more Irregularities were induced after FS-LASIK over the 8-mm zone.

Corneal Irregular Astigmatism and Curvature Changes After Small Incision Lenticule Extraction: Three-Year Follow-Up.

PURPOSE: To evaluate the long-term changes in anterior and posterior corneal irregular astigmatism and curvatures after small incision lenticule extraction (SMILE). METHODS: Fifty eyes of 28 patients underwent SMILE for myopic astigmatism. All procedures were performed using the VisuMax® femtosecond laser. A Scheimpflug camera was used for preoperative and 3-year postoperative tomography. Anterior and posterior corneal Fourier parameters (spherical component, regular astigmatism, asymmetry, and irregularity) and curvature data were evaluated and compared within 2 subgroups according to the magnitude of the refractive correction (low myopia group: spherical equivalent (SEQ) ≥ -6 D; high myopia group: (SEQ) < -6 D). Associations between all studied parameters were examined. RESULTS: Three years postoperatively, an increase in anterior corneal curvatures and Fourier parameters was detected and the results were strongly correlated with the preoperative SEQ, lenticule thickness, and volume. At the posterior cornea, the flattest radius, corneal astigmatism, spherical component, regular astigmatism, and irregularity decreased only in the high myopia group. A correlation was found between changes in posterior astigmatism and changes in anterior radii (R = 0.349, P = 0.014), SEQ (R = 0.396, P = 0.0049), and lenticule thickness (R = -0.414, P = 0.0031). Moreover, changes in posterior corneal irregularity correlated with the changes in anterior and posterior radii (R = -0.3, P = 0.034, and R = 0.449, P = 0.0012, respectively), changes in preoperative SEQ (R = 0.284, P = 0.0477), and lenticule thickness (R = -0.311, P = 0.0298). CONCLUSIONS: Three years after SMILE, there was a reduction of posterior astigmatism in high refractive corrections. This could result in undercorrection in high refractive treatments. Total irregularities increased despite the compensatory effect of the posterior corneal surface.

Femtosecond Lenticule Extraction (FLEx) for Spherocylindrical Hyperopia Using New Profiles.

PURPOSE: To investigate new lenticule profiles for the treatment of hyperopia by femtosecond lenticule extraction (FLEx) for spherocylindrical hyperopia using a modified laser scan sequence. METHODS: In this prospective 9-month study, 39 eyes of 22 patients with the mean age of 49 years (range: 27 to 56 years) underwent hyperopic FLEx. The mean optical zone was 6 mm (range: 5.75 to 6.75 mm) with keratometry readings and magnitude of correction adjusted mean transition zone of 2.1 mm (range: 1.80 to 2.89 mm). The lenticule thickness was set at 25 µm in the center and 10 µm at the edge. RESULTS: Preoperative spherical equivalent manifest refraction was +1.96 ± 1.04 diopters (D) (range: +0.63 to +4.50 D). Because of the presbyopic age, the treatment was aimed at low myopia in 75% of the eyes treated. At the final 9-month follow-up visit, the mean spherical equivalent was -0.40 ± 0.61 D (range: -1.50 to +0.75 D), with 70% of eyes treated within ±0.50 D and 89% of eyes within ±1.00 D of intended correction. The regression was +0.29 D between 1 week and 6 months but 0.03 D between 6 and 9 months. A total of 10% of eyes lost one line of corrected distance visual acuity, respectively. There were no losses of two or more lines of visual acuity or any serious intraoperative or postoperative complications. CONCLUSIONS: Treatment of spherocylindrical hyperopia by FLEx led to refractive results similar to published outcomes on hyperopic femtosecond laser-assisted LASIK. [J Refract Surg. 2018;34(1):6-10.].

Foveal pit morphology evaluation during optical biometry measurements using a full-eye-length swept-source OCT scan biometer prototype.

PURPOSE: To assess the scan quality of foveal pit morphology (FPM) and to quantify central retinal thickness (CRT) during routine optical biometry measurements with a full-eye-length swept-source optical coherence tomography (SS-OCT) scan biometer prototype (IOLMaster700) and to compare these results with standard examinations using spectral-domain optical coherence tomography (SD-OCT) technique (Cirrus4000 SD-OCT). METHODS: As part of a SS-OCT scan protocol to measure biometric parameters for intraocular lens power calculation, central horizontal 1 mm retinal B scans were taken from phakic (group I) and pseudophakic (group II) nonvitrectomized eyes. To evaluate FPM, macular scans of either examination technique were subjectively analyzed and compared. Repeated CRT measurements were performed to analyze repeatability and consistency of IOLMaster700 recordings. These results were compared with CRT evaluations using SD-OCT. RESULTS: Overall, 146 eyes of 146 patients were included in this series. The subjective assessments of FPM are illustrated. Repeated CRT measurements (repeatability) with the IOLMaster700 disclosed an overall intraclass correlation of 0.57 (group I: 0.48; group II: 0.89). Overall coefficient of variation (accuracy) was calculated to be 12.43% (group I: 14.21%; group II: 5.66%). The comparison of CRT measurements between both devices showed significant differences in group I (p = 0.006). CONCLUSIONS: Compared with SD-OCT, resolution of the 1 mm retinal B scan of SS-OCT scan biometry was lower. However, advanced pathologic characteristics were clearly discernible. Repeatability and accuracy of CRT measurements were acceptable though lower than with the standard SD-OCT technique. The CRT differed significantly in eyes of particular interest (group I) between both devices. The new scan could provide useful information for subsequent patient examination and further treatment planning for cataract surgery.

The vitreomacular interface in retinal vein occlusion.

PURPOSE: To evaluate the posterior vitreous adhesion status in patients with a history of central or branch retinal vein occlusion and to compare the results with the natural time-course of posterior vitreous detachment in healthy age-related controls. METHODS: A retrospective chart review in terms of the posterior vitreous adhesion status was performed in 132 patients (133 eyes) with a history of a central (CRVO) or branch (BRVO) retinal vein occlusion. All patients underwent vitrectomy. Based on the operation reports, the vitreous adhesion status was classified as attached, partially detached or completely detached. The results were compared to the natural time-course of posterior vitreous detachment development in healthy age-related controls. RESULTS: Eighty-one eyes met the inclusion and exclusion criteria. Fifty-two eyes (64%) had a history of CRVO and 29 eyes (36%) a history of BRVO, respectively. In the CRVO group, the posterior vitreous was attached in 47 eyes (90%) and completely detached in five eyes (10%). In the BRVO group, the posterior vitreous was attached in 27 eyes (93%), partially detached in 1 eye (3%) and completely detached in another eye (3%). A subdivision into age classes and a comparison with healthy age-related controls [data by Weber-Krause & Eckardt (1997) Ophthalmologe, 94, 619-623] showed in patients between 65 and 69 years of age an attached posterior vitreous cortex in 72% in healthy eyes, in 100% in CRVO (p = 0.109) and in 89% in BRVO (p = 0.440), in patients between 70 and 79 years of age an attached posterior vitreous cortex in 56% in healthy eyes, in 86% in CRVO (p = 0.010) and in 100% in BRVO (p = 0.038) and in patients between 80 and 89 years of age an attached posterior vitreous cortex in 43% in healthy eyes, in 100% in CRVO (p = 0.191) and in 67% in BRVO (p = 0.582) (Fisher's exact t-test). CONCLUSION: In patients with a history of CRVO or BRVO, the posterior vitreous cortex stays attached more frequently in all age groups in comparison with the healthy age-related controls.