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Abstract Background Visual quality after corneal refractive surgery is linked to the postoperative effective optical zone (EOZ). This study aims to compare long-term changes in the EOZ following small incision lenticule extraction (SMILE) and femtosecond laser-assisted in-situ keratomileusis (FS-LASIK) for moderate and high myopia. Methods This study included 42 patients (72 eyes) who underwent either SMILE (36 eyes) or FS-LASIK (36 eyes). A custom software program based on the tangential curvature difference map of the Pentacam HR (Oculus Optikgeräte GmbH) was used to define the EOZ at 3 and 7 years postoperatively. The EOZ, its chronological changes compared to the programmed optical zone (POZ), and the corneal wavefront aberrations following SMILE and FS-LASIK were analyzed. Correlations between the EOZ changes and relevant parameters were evaluated. Results Three years postoperatively, EOZ following SMILE and FS-LASIK were 5.13 ± 0.27 mm and 4.70 ± 0.24 mm (P

Abstract Background Transepithelial corneal crosslinking (CXL) is a novel surgical approach for the treatment of keratoconus, which is a bilateral asymmetrical ophthalmological disease accompanied by progressive corneal ectasia. Silicon hydrogel (SiH) contact lenses have been extensively used in clinical ophthalmologic medicine, as a postoperative ophthalmological intervention. However, the ideal lens application duration after transepithelial CXL remains uncertain. Here, we aimed to investigate the effects and comfort of immediate corneal contact lens use after transepithelial CXL for keratoconus. Methods In this prospective study, 60 patients with keratoconus who underwent transepithelial CXL treatment were enrolled from September 2021 to January 2023 with a male:female ratio of 39:21, and an average age of 25.42 ± 5.47 years. The patients were divided randomly into two groups: group A contained 30 patients wearing silicone hydrogel contact lenses for 7 days postoperatively, and group B contained 30 patients wearing the same contact lenses for 3 days. Ten subjective ophthalmologic symptoms were surveyed by the patients, including pain, photophobia, foreign body sensation, tearing, burning, blurred vision, dry eyes, difficulty opening the eyes, astringency, and stinging. Ophthalmologic signs, including corneal edema and conjunctival congestion, were recorded by a single clinician on postoperative days 1, 3, and 7. Results Each surgical procedure was readily performed without complications, and both groups postoperative day 7 (P = 0.04), where group B scored (0.01 ± 0.41) lesser than group A (0.12 ± 0.29), whilst corneal edema in both groups recorded significantly different on postoperative days 5 and 7 (group A demonstrated the result of 0.17 ± 0.14 and 0.08 ± 0.11 for the respective days, whereas group B indicated 0.10 ± 0.13 and 0.03 ± 0.07 at the corresponding times). Conclusions Immediate use of silicone hydrogel corneal lenses after transepithelial CXL effectively alleviates postoperative ocular distress, particularly with a three-day use period as the ideal duration.

Abstract Purpose To evaluate the accuracy of axial length, keratometry, and refractive measurement with Myopia Master in ametropic children. Methods In this randomized prospective cross-sectional study, 125 children with ametropia (250 eyes) were recruited (55 boys and 70 girls; age range: 3–15 years). All examinations were performed under full cycloplegic conditions. Measurements of axial length (AL), keratometry, and autorefraction acquired with the Myopia Master were compared with those from the IOLMaster 500, IOLMaster 700, Nidek ARK-1, and manifest refraction. The differences between the different methods were analyzed, and their correlation was assessed by interclass correlation coefficients (ICCs), Bland–Altman plot, and correlation test. Results The ALs (mm) measured with Myopia Master, IOLMaster 500, and IOLMaster 700 were 23.67 ± 1.26, 23.68 ± 1.26, and 23.70 ± 1.25, respectively. The mean values and standard deviations for AL and keratometry readings from these devices were similar (P ≥ 0.059). The ICC analysis also revealed high consistency between the measurements (ICC ≥ 0.943). Additionally, the correlation coefficients were relatively high (r > 0.9, p

Abstract Background To study the impact of unintended initial dissection of the posterior plane (UIDPP) on operation time and surgical outcomes during small incision lenticule extraction (SMILE) surgery. Methods This was a retrospective study. Based on the SMILE procedure video, the operating eyes were assigned to the normal and UIDPP groups according to the presence or absence of UIDPP signals during surgery. The UIDPP group was further separated into early and late detection based on whether the complete dissection of the lenticule posterior plane or not. Patient's demographic data, preoperative evaluation data, operation time and postoperative outcomes were collected. Results Sixty-six patients (66 eyes) who underwent SMILE were included, with 24 eyes with UIDPP (13 in the early detection group and 11 in the late group). The optical zone was smaller (median 6.5 vs. 6.6, P = 0.007), and the operation time was longer (median, 189.5 vs. 91.0 s, P

Abstract Purpose To assess the ability of the Pentacam in predicting the corneal power after hyperopic small-incision lenticule extraction (SMILE). Methods Twenty-five eyes of 22 patients underwent hyperopic SMILE were prospectively followed. All patients finished at least 6 months visit. Cornea power was obtained by Pentacam HR, in the format of mean keratometry (Km), equivalent keratometry (EKR) and total cornea refractive power (TCRP). Calculation of TCRP were centered on either the corneal apex or the pupil center within a ring or zone, giving a total of four different subtypes naming AR、AZ、PR、PZ. Clinical history method (CHM) was regarded as a gold standard and was compared with other cornea power parameters. Results Center difference had no impact on the TCRP values (PR vs AR and PZ vs AZ, P > 0.05). Compared with CHM, no difference was found in Km, EKR 4.0 mm, EKR 4.5 mm, PR 3.0 mm, PR 4.0 mm, AR 3.0 mm and AR 4.0 mm. PR 4.0 mm showed the least difference with CHM (− 0.14 ± 1.03D, P > 0.05). The 95% limit of agreement (LOA) of the TCRPs and CHM was not close. The top two were PR 3.0 mm and PR 4.0 mm, LOA of which were − 2.20 to 1.84 D and − 2.18 to 1.68 D respectively. Central cornea thickness was correlated with error (TCRP – CHM) of PR 4.0 mm (r = 0.58, P = 0.003). Conclusions The Pentacam topographer is an alternative method of measuring corneal power in eyes after hyperopic SMILE. The optimal options seem to be the TCRP (PR 4.0 mm). The agreement needs more verifications.

Abstract Background To evaluate lenticule surface characteristics of small incision lenticule extraction (SMILE) for hyperopia correction in rabbits. Methods The left and right eyes of 8 rabbits were divided into two groups. The right eyes were assigned to a myopia group, and the left eyes to a hyperopia group. The rabbits received SMILE procedures with + 3.00 D and − 3.00 D correction for the hyperopia and myopia groups, respectively. Extracted lenticules were examined via scanning electron microscopy. Lenticules from odd-numbered rabbits were accessed with the anterior surface, and lenticules from even-numbered rabbits were observed with the posterior surface. A previously established scoring system was used to evaluate lenticule surface characteristics. Statistical analysis was conducted to compare the scores between the two groups. Results All procedures were performed successfully, and the lenticules were extracted smoothly. One myopia lenticule that was facing downward was handled failed in preparation for imaging, thus 15 lenticules were ultimately graded. Twelve lenticules exhibited smooth surfaces, and regularly arranged tissue bridges were observed in almost all regions. Three lenticules exhibited a partially rough surface and irregularities affecting more than 10% of the lenticules (2 in the hyperopia group and 1 in the myopia group). Rough lenticules occurred in twice as many lenticules in the hyperopia group compared to the myopia group. Conclusions Scan quality of lenticules after SMILE for hyperopia correction is comparable to that of myopia lenticules. The shape of hyperopic lenticule may increase the difficulty of surgical manipulation and result in surface roughness.

Abstract Background High myopia with shallow anterior chamber depth (ACD less than 2.8 mm) is not rare. This observational study aims to evaluate visual outcomes after implantation of the Visian Implantable Collamer Lens with a central hole (ICL V4c) in these patients. Methods A prospective cohort of consecutive 51 eyes of 31 patients (20 to 42 years old) was followed for at least 12 months (average 15.35 ± 4.90 months, rangers from 12 to 25 months). The preoperative ACD was 2.74 ± 0.04 mm (2.65 to 2.79 mm). Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), intraocular pressure (IOP), manifest refraction, vault, and endothelial cell density (ECD) were measured during the follow-ups after surgery. Results All surgeries were performed safely and no complication was observed during the follow-ups. At the last follow-up, the safety index (postoperative CDVA / preoperative CDVA) was 1.33 ± 0.60 and the efficacy index (postoperative UDVA / preoperative CDVA) was 1.14 ± 0.54. After the surgery, no eye had decreased CDVA and 59% (30 eyes) of the eyes gained at least one line. Forty-seven eyes (92%) were within ±1.0 D and 35 eyes (69%) were within ±0.5 D of the attempted refraction. The mean postoperative vault was 380.00 ± 152.84 μm (90 to 700 μm). The ECD was reduced by 8.38 ± 0.06% as compared to the preoperative value (p

Abstract Background To report a first case of lenticule addition and corneal cross-linking for post-LASIK ectasia with associated corneal thinning. Case presentation Lenticule addition followed by corneal cross-linking was performed on the left eye of a patient with post-LASIK ectasia. Postoperatively, the corneal power and elevation were stable with a remarkable improvement in corneal thickness, and the lenticule had merged with the adjacent corneal stroma at 30 months follow-up. The patient’s corrected distance visual acuity gained two lines. Conclusions This case provides a potential treatment option for patients with keratectasia and keratoconus in association with thin corneal thickness (less than 400 μm) and may provide the benefit of delaying or avoiding the need for keratoplasty, which has its own associated complications and is limited by the availability of donor corneas.

Abstract Background To describe the clinical features of acquired progressive esotropia, with a larger angle at distance than near, associated with myopia in young adults. Methods Eleven adults (ages ranging from 18 to 37 years) with constant or intermittent horizontal diplopia at distance were recruited. Subjective refraction, ocular alignment, fusional amplitudes and horizontal eye movements were measured at distance and near. Results Distance esotropia varied from 20 to 60 prism diopters (PD). At near, the esotropic deviation ranged from 10 to 30 PD. Spherical equivalents (SE) of the right eye ranged from − 3.50 to − 8.25 diopters (D) while SE of the left eye ranged from − 0.375 to − 7.25 D. Ten of the eleven patients presented with constant diplopia at distance. Horizontal ductions and versions were full in all patients. The pathological report of seven patients who underwent lateral rectus resection showed that there were no muscle fibres, but rather, collagenous fibres. Conclusions This unusual sub-type of strabismus is a benign entity with slow progression that can occur in young adults with myopia. The cause of this condition is still unknown, and may be related to long periods of near work.

Abstract Background To report a first case of late-onset diffuse lamellar keratitis (DLK) occurring 4 years after femtosecond laser-assisted small incision lenticule extraction (SMILE). Case presentation A 41-year-old man who underwent SMILE 4 years prior developed DLK in the right eye 1 day after he was struck in the eye by a finger while playing with his son. Slim-lamp microscopy and anterior segment optical coherence tomography (AS-OCT) were used to evaluate the cornea of the right eye. Slit-lamp examination of the right eye revealed epithelial exfoliation and stage 3 DLK with diffuse, dot-like, granular haze in the interface between the cap and stromal bed. After intensive treatment with topical corticosteroids, the DLK resolved and corneal transparency was achieved. Conclusions This case indicates that DLK can occur several years after SMILE. Ocular trauma may be a risk factor for the development of DLK. The prognosis is usually favorable with early diagnosis and treatment with topical corticosteroids.

Abstract Background To investigate the visual and refractive outcomes in patients with mild to moderate myopia after laser-assisted subepithelial keratectomy (LASEK) using the 500 Hz pulse rate of the Triple-A profile. Methods Thirty-six eyes of 20 patients (mean age, 27.5 ± 4.6 years) were included in this prospective, consecutive study. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), corneal topography, and corneal aberrations were measured preoperatively and 1 day, 1 week, 1, 3 and 6 months post-operation. Results At 1 week after surgery, UDVA was better than or equal to 20/25 in all eyes. At postoperative 6 months, the efficacy and safety index was 1.05 ± 0.13 and 1.12 ± 0.15, respectively; all eyes had a UDVA of 20/20 or better, and no eyes showed a loss in CDVA; 100% of the eyes were within ±1.00 D of the attempted spherical equivalent (SE) correction. Conclusion The postoperative results indicate that using the Triple-A ablation profile of the MEL 90 excimer laser with a 500 Hz pulse rate is a safe, efficient, and predictable method to correct mild to moderate myopia.

Abstract Background To report a case of interface fluid syndrome (IFS) following small incision lenticule extraction (SMILE) evaluated with corneal densitometry and optical coherence tomography (OCT). Case presentation An 18-year-old man reported sudden vision loss 24 days after SMILE procedure. Intraocular pressure (IOP) was 36.3 mmHg (OD) and 36.7 mmHg (OS) by noncontact tonometry. Moderate corneal edema, interface fluid pocket and haze were observed by OCT and confirmed by corneal densitometry values. Discontinuation of steroids and addition of hypotensive medication were offered immediately. The symptoms were cured after the medication. Changes of corneal densitometry were consistent with the clinical course of IFS. Conclusion This case illustrates that it is crucial to be aware that a history of SMILE can also cause IFS. Both OCT and corneal densitometry can serve as auxiliary means to evaluate the clinical course of IFS, and appropriate IOP management is an effective approach.

Background: To investigate accommodative response and accommodative lag changes after femtosecond laser small incision lenticule extraction (SMILE) for moderate to high myopia correction. Methods: A total of 32 eyes of 32 patients with no strabismus who underwent SMILE were enrolled in this prospective clinical study. The accommodative response was obtained viewing monocularly with spherical equivalent refractive error corrected, using an open-field autorefractor at different stimulus levels (2.00D, 2.50D, 3. 00D, 4.00D and 5.00D) for the right eye before a standard SMILE surgery and at 1-month follow-up after surgery. Results: The mean age of the patients were 23.34 ± 2.90 years and the mean preoperative manifest refraction spherical equivalent was -5.74 ± 1.98 diopters. Significant differences were detected in both preoperative and postoperative accommodative responses to different stimulus levels (P < 0.001). Multiple linear regression model analysis revealed preoperative manifest refractive spherical equivalent (P = 0.006) and preoperative accommodative lag (P = 0.04) showed a significant impact on postoperative accommodative lag. Conclusions: This is the first report of accommodative changes after SMILE. Our preliminary results showed that a decrease in postoperative accommodative lag that might be related to the relief of the visual discomfort symptom. [ABSTRACT FROM AUTHOR]

Background: To investigate long-term refractive outcomes, wavefront aberrations and quality of life after small incision lenticule extraction (SMILE) for moderate to high myopia.Methods: A total of 26 patients (47 eyes) with preoperative mean spherical equivalent (SE) of -6.30 ± 1.47 diopters (D) who underwent SMILE were recruited. The measurements included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, wavefront aberrations, and quality of life.Results: At 4 years postoperatively, UDVA was better than or equal to 20/20 in 92 % of eyes. The efficacy index was 1.07 ± 0.16. 89 % of eyes were within ± 0.5 D of the intended refractive target. No eye lost any Snellen lines. The safety index was 1.16 ± 0.14. No significant changes of SE occurred among postoperative follow-ups at months 1, 3, 6 and years 1, 2, 4 (P > 0.05, Scheffe test). Higher-order aberrations, coma, spherical aberration and higher-order astigmatism increased postoperatively, and no significant changes of aberrations were detected among the 1-month, 6-month or 4-year follow-ups postoperatively (37 eyes). Compared to the spectacles group, the surgery group showed a significantly higher total score on quality of life (45.71 ± 2.61 vs 39.96 ± 3.56, P < 0.001).Conclusions: SMILE provides a predictable and stable correction of moderate to high myopia as documented by long-term follow-up. [ABSTRACT FROM AUTHOR]