Effect of brimonidine tartrate 0.2% ophthalmic solution on visual quality after implantable collamer lens implantation with a central hole.

PURPOSE: To investigate the effect of brimonidine tartrate 0.2% on visual quality after implantable collamer lens with a central hole (ICL V4c). METHODS: This study comprised 59 consecutive patients implanted with an ICL V4c. Brimonidine was administered randomly into one eye of the patients with symptomatic glare or halos 1 week postoperatively and the contralateral eye with artificial tears as the control group. Visual quality (measured by a optical quality analysis system), pupil size and refraction under scotopic light conditions were measured before and 0.5, 1.5, 3 and 6 h after administration of brimonidine. A symptom questionnaire was also evaluated. RESULTS: The visual quality improved and reached its maximum value, and the scotopic pupil size reached its minimum value 1.5 h after brimonidine administration, with a statistically significant difference seen from 0.5 to 3 h compared to baseline. No changes in refraction were seen after brimonidine. The questionnaire showed that symptoms of glare or halos could be eliminated after brimonidine in 58% of patients, be alleviated in 37% of patients and be unchanged in 5% of patient. However, 10% of patients experienced conjunctival congestion and some patients experienced reduced drug efficacy 1 month after treatment. CONCLUSION: Brimonidine can be used to improve night visual quality in early postoperative period after ICL V4c implantation. It helps patients to quickly adapt to the glare or halos.

Correction to: Thickness profiles of the corneal epithelium along the steep and flat meridians of astigmatic corneas after orthokeratology.

An amendment to this paper has been published and can be accessed via the original article.

Thickness profiles of the corneal epithelium along the steep and flat meridians of astigmatic corneas after orthokeratology.

BACKGROUND: The aim of this study was to investigate the changes in corneal epithelial thickness along the principle meridians of astigmatic corneas after six months of overnight spherical myopic orthokeratology (OK) lens wear. METHODS: This is a prospective study. Fifty-seven subjects with up to 1.50 diopters (D) of corneal toricity wore spherical OK lenses for 6 months. Evaluations of OK lens fit, visual acuity, refractions and corneal toricity (CT) were performed. Fourier-domain optical coherence tomography (FD-OCT) was conducted to measure the corneal epithelial thickness (ET) along the principle meridians of corneal toricity over a diameter of 6 mm. The means of △ET of the same diameter at individual meridians (△ETSm and △ETFm) were calculated and compared. RESULTS: Visual acuity and refraction improved significantly after OK lens wear. △ETFm thinned more than △ETSm (P = 0.027) at 1.5 mm in radius. △ETSm thickened more than △ETFm at 2.5 mm (P = 0.019) and 3.0 mm (P = 0.036).∣△ETSm - △ETFm∣ were significantly correlated with the baseline central CT at 2.0 mm, 2.5 mm and 3.0 mm. ∣△ETSm - △ETFm∣was significantly correlated with the baseline peripheral CT at 2.5 mm. CONCLUSIONS: Overnight wear of spherical OK lenses resulted in differential changes in the thickness profiles of the corneal epithelium between the steep and flat meridians in eyes with corneal toricity.

Comparison of early changes in and factors affecting vault following posterior chamber phakic Implantable Collamer Lens implantation without and with a central hole (ICL V4 and ICL V4c).

BACKGROUND: To objectively compare the early changes in vault over time following implantation of an Implantable Collamer Lens without (ICL V4) and with (ICL V4c) a central hole and the respective factors affecting vault change in moderate to high myopia. METHODS: This prospective study comprised of 38 eyes of 38 patients implanted with ICL V4 and 39 eyes of 39 patients implanted with ICL V4c intraocular lenses. We quantitatively assessed the postoperative values of vault and pupil size at 1 day, 1 week, and 1 month following implantation using a rotating Scheimpflug camera (Pentacam). We compared these postoperative values within and between the two groups and identified the factors affecting vault change. RESULTS: The mean vaults at 1 day, 1 week, and 1 month following ICL V4 implantation were 303.68 ± 185.11, 517.89 ± 160.07 and 521.32 ± 155.72 µm respectively, and those following ICL V4c were 316.67 ± 186.89, 495.13 ± 180.84 and 510.77 ± 175.51 µm, respectively. There was a significant difference in vault between 1 day and 1 week postoperatively. There was a significant association between the vault change and the pupil size change in both groups from 1 day to 1 month postoperatively (Pearman correlation coefficient; ICL V4: r = 0.585, P = 0.001; ICL V4c: r = 0.588, P <0.001). The vault value 1 month after implantation of ICL V4 and ICL V4c was associated with the preoperative anterior chamber depth, horizontal corneal diameter, horizontal and vertical sulcus-to-sulcus. CONCLUSIONS: Pupil movement is a critical factor in vault change, with increasing vault observed postoperatively from 1 day to 1 week associated with the declining effects of pharmacological miosis and increasing pupil size. The anterior chamber depth, horizontal corneal diameter, horizontal and vertical sulcus-to-sulcus show some correlation with vault.

Comparison of efficacy and visual outcomes after SMILE and FS-LASIK for the correction of high myopia with the sum of myopia and astigmatism from -10.00 to -14.00 dioptres.

PURPOSE: To compare the efficacy and visual outcomes after femtosecond laser small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) in correcting high myopia. METHODS: This prospective, randomized study included patients who underwent SMILE or FS-LASIK for the correction of high myopia [the sum of spherical and cylindrical error from -10.00 to -14.00 dioptres (D)]. Preoperative, 1-month (P1m), 3-months (P3m) and 6-months (P6m) postoperative outcomes were analysed and compared between the two procedures. RESULTS: Ninety-six right eyes of 96 patients (SMILE: n = 51, FS-LASIK: n = 45) were included. Both the (Attempted - achieved) sphere and the (attempted - achieved) spherical equivalent (SEQ) were greater in the FS-LASIK group at all three postoperative time-points (p < 0.001). The postoperative vector means of astigmatism were smaller in the SMILE group than in the FS-LASIK group. The differences between the optical zone of tissue removal (ROZ) during surgery and the postoperative functional optical zone (FOZ; ROZ-FOZ) were smaller in the SMILE group than in the FS-LASIK group. No significant difference was found between the two procedures in the delta-root mean square (RMS) of aberrations, except for delta-spherical aberration (SA) at P3m. CONCLUSIONS: Both SMILE and FS-LASIK are effective in correcting high myopia. SMILE resulted in less under-correction, less regression, a smaller decrease in the FOZ and a smaller increase in SA when compared to FS-LASIK, resulting in better visual outcomes with SMILE.

Comparison of Corneal Power and Astigmatism between Simulated Keratometry, True Net Power, and Total Corneal Refractive Power before and after SMILE Surgery.

Purpose. To compare the mean corneal power (Km) and total astigmatism (Ka) estimated by three methods: simulated keratometry (simK), true net power (TNP), and total corneal refractive power (TCRP) before and after femtosecond laser small incision lenticule extraction (SMILE) surgery. Methods. A retrospective, cross-sectional study. SimK, TNP, and TCRP from a Scheimpflug analyzer were obtained from 144 patients before and 6 months after SMILE surgery. Km and Ka were recorded as the mean of individual paracentral rings of 1.0 to 8.0 mm (R1 to R8). The surgically induced changes in Km (delta-simK, delta-TNP, and delta-TCRP) and Ka (delta-simKa, delta-TNPa, and delta-TCRPa) were compared to the changes in spherical equivalent of the cycloplegic refraction (delta-SE) and astigmatism (delta-RA). Results. Preoperatively, astigmatism values were greatest with simKa from R1 to R5 and greatest with TCRPa from R6 to R8. Astigmatism values were smallest with TNPa from R1 to R7. Postoperatively, astigmatism values were greatest with simKa from R1 to R5 and greatest with TCRPa from R6 to R8. Delta-TCRP3 and Delta-TCRP4 matched delta-SE most closely, and delta-TCRPa3 matched delta-RA most closely. Conclusions. TCRP proved to be the most accurate method in estimating corneal power and astigmatism both before and after SMILE surgery.