Vector analysis of astigmatic correction after small-incision lenticule extraction and femtosecond-assisted LASIK for low to moderate myopic astigmatism

Chan, Tommy C Y; Ng, Alex; Cheng, George P.M.; Wang, Zheng; Ye, Cong; Woo, Victor C.P.; Tham, Clement C.; Jhanji, Vishal

doi:10.1136/bjophthalmol-2015-307238

Cited by 91 publications

(87 citation statements)

References 26 publications

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“…Ivarsen and Hjortdal reported that undercorrection of astigmatism increased with attempted treatment following SMILE16. Undercorrection of astigmatic error has been reported in previous studies comparing SMILE to other corneal refractive surgeries8171819. The CI was very close to 1.0 for SMILE in our cohort, representing accurate astigmatic correction.…”

Section: Discussionsupporting

confidence: 83%

“…This emphasizes the importance of treatment alignment for successful correction of astigmatism, in addition to the treatment magnitude. Correction of low astigmatism is particularly a concern because of a higher tendency towards larger axis deviations upon vector analysis81923. The spread of absolute AE was much wider for correction of low astigmatism for both procedures.…”

Section: Discussionmentioning

confidence: 98%

“…Small-incision lenticule extraction (SMILE) is a flapless, all femtosecond refractive surgery technique in which a corneal stromal lenticule is fashioned using femtosecond laser and removed through a small peripheral corneal incision34. Previous studies have demonstrated that SMILE is safe and effective for management of myopia and myopic astigmatism5678. A retrospective study comparing SMILE and laser-assisted subepithelial keratectomy showed that changes in corneal hysteresis and corneal resistance factor induced by SMILE are more predictable than those induced by laser-assisted subepithelial keratectomy9.…”

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confidence: 99%

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Early outcomes after small incision lenticule extraction and photorefractive keratectomy for correction of high myopia

Chan

et al. 2016

Sci Rep

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We prospectively compared visual and refractive outcomes in patients with high myopia and myopic astigmatism after small-incision lenticule extraction (SMILE) and photorefractive keratetctomy (PRK) with mitomycin C. Sixty-six eyes of 33 patients (mean age, 29.7 ± 5.6 years) were included (SMILE: 34 eyes, PRK 32 eyes). Preoperatively, no significant difference was noted in manifest spherical equivalent (p = 0.326), manifest sphere (p = 0.277), and manifest cylinder (p = 0.625) between both groups. At 1 month, there were significant differences in logMAR uncorrected distance visual acuity, efficacy index and manifest refraction spherical equivalent between SMILE and PRK (p ≤ 0.029). At 6 months, the logMAR corrected distance visual acuity (p = 0.594), logMAR uncorrected visual acuity (p = 0.452), efficacy index (p = 0.215) and safety index was (p = 0.537) was comparable between SMILE and PRK. Significant differences were observed in postoperative manifest spherical equivalent (p = 0.044) and manifest cylinder (p = 0.014) between both groups. At the end of 6 months, 100% of the eyes in SMILE group and 69% of the eyes in PRK group were within ±0.50 D of the attempted cylindrical correction. The postoperative difference vector, magnitude of error and absolute angle of error were significantly smaller after SMILE compared to PRK (p ≤ 0.040) implying a trend towards overcorrection of cylindrical correction following PRK.

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Section: Discussionsupporting

confidence: 83%

Section: Discussionmentioning

confidence: 98%

mentioning

confidence: 99%

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Early outcomes after small incision lenticule extraction and photorefractive keratectomy for correction of high myopia

Chan

et al. 2016

Sci Rep

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“…Data from various studies suggest that this modality is a safe and effective method to correct varying degrees of myopia, with the advantages of minimum postoperative discomfort and restrictions, less dry eye, and probably better biomechanics compared to LASIK 9,10. Studies comparing the results of astigmatism correction with ReLEx SMILE and LASIK, however, showed better outcomes with LASIK, most likely due to non-availability of iris registration and eye tracker in the current version of the femtosecond laser used for the ReLEx SMILE procedure 11,12. However, similar comparison studies have not been reported between T-ICL and ReLEx SMILE.…”

Section: Introductionmentioning

confidence: 99%

Matched population comparison of visual outcomes and patient satisfaction between 3 modalities for the correction of low to moderate myopic astigmatism

Ganesh¹,

Brar²,

Pawar³

2017

OPTH

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PurposeTo compare toric implantable collamer lens (T-ICL), femto-LASIK, and ReLEx SMILE for the treatment of low to moderate myopic astigmatism in terms of long-term visual and refractive outcomes and predictability of astigmatic correction.Materials and methodsThe study included 30 eyes from 30 patients between the age groups of 21 and 40 years, undergoing bilateral surgery with any of the three procedures – T-ICL, femto-LASIK, or ReLEx SMILE – for correction of myopic astigmatism within the range of −3 to −8 D spherical equivalent (SE), with a minimum astigmatism of −0.75 D. Patients were followed up at day 1, 1 month, 6 months, and 1 year.ResultsAt 1 year, the mean cylinder reduced to −0.21±0.28, −0.17±0.36, and −0.22±0.28 D in the T-ICL, femto-LASIK, and ReLEx SMILE group, respectively. The predictability of astigmatism correction was comparable, with no statistically significant difference between the 3 groups (P>0.05). A total of 97% of eyes in ReLEx SMILE achieved a uncorrected distance visual acuity of 20/20 or better, compared to T-ICL (93%) and FS-LASIK (90%). However, gain in lines of corrected distant visual acuity (CDVA) was maximum in T-ICL group (60%). Four eyes in the femto-LASIK group had loss of CDVA by one line. Three eyes required exchange due to high vault and rotation of the T-ICL, which did not affect the final outcome.ConclusionAll 3 modalities were effective for myopic astigmatism at the end of 1 year. Quality of vision and patient satisfaction with T-ICL and ReLEx SMILE were similar and better than FS-LASIK. However, slight chances of postoperative rotation and exchange exist with T-ICL, which warrant thorough preoperative planning.

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“…We have previously reported that the effect of learning curve could affect the visual and refractive outcomes 17. In our hydroexpression group, there were less residual cylinder, and this could be due to effect of learning curve in head positioning and centration during SMILE, as these were the key factors in SMILE astigmatic correction 6. Nevertheless, in our forceps group period (2014), we already had more than 2 years of experience.…”

Section: Discussionmentioning

confidence: 78%

Comparing a new hydroexpression technique with conventional forceps method for SMILE lenticule removal

Cheng

Woo

et al. 2017

Br J Ophthalmol

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Vector analysis of astigmatic correction after small-incision lenticule extraction and femtosecond-assisted LASIK for low to moderate myopic astigmatism

Cited by 91 publications

References 26 publications

Early outcomes after small incision lenticule extraction and photorefractive keratectomy for correction of high myopia

Early outcomes after small incision lenticule extraction and photorefractive keratectomy for correction of high myopia

Matched population comparison of visual outcomes and patient satisfaction between 3 modalities for the correction of low to moderate myopic astigmatism

Comparing a new hydroexpression technique with conventional forceps method for SMILE lenticule removal

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