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Purpose: To compare the visual outcomes following topography?guided laser in situ keratomileusis (LASIK) treatment using manifest refraction versus a new topography analysis software. Methods: A prospective, randomized, observer?masked contralateral study was conducted in the refractive services of a tertiary eye care hospital in South India. Analysis of visual outcomes, corneal higher?order aberrations, and contrast sensitivity were performed at 3 months postoperative visit following uneventful topography?guided LASIK using the Wavelight EX500. One eye was treated with the Contoura platform using manifest refraction (Contoura), while the contralateral eye was treated using an ablation profile planned by the Phorcides Analytic Engine (Phorcides). Results: Sixty eyes of 30 patients were included in the study. At 3 months postoperative visit, the uncorrected distance visual acuity (UDVA) in the Contoura and Phorcides groups was logarithm of the minimal angle of resolution (logMAR) 0.04 ± 0.07 and logMAR 0.06 ± 0.1, respectively (P = 0.483). Postoperative manifest refractive spherical error (MRSE) was 0.12 ± 0.22 and ? 0.06 ± 0.20 D in the Contoura and Phorcides groups, respectively (P = 0.338). Although higher number of eyes demonstrated a gain in one or more lines of corrected distance visual acuity (CDVA) in the Contoura group (16.6% vs. 6.6%), the difference was not statistically significant (P = 0.361). Vector analysis (Alpins criteria) for postoperative cylinder, contrast sensitivity measurement, and corneal higher?order aberration profile showed no significant difference between the two groups at 3 months postoperative visit (P = 0.213, 0.514, and 0.332, respectively). Conclusion: Quantitative and qualitative visual outcomes with the Phorcides Analytic Software were similar to the Contoura treatment using manifest refraction.
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AIM: To explore the clinical efficacy of the myopic with moderate to high astigmatism correction between corneal topography-guided femtosecond laser in situ keratomileusis(FS-LAISK)and Toric implantable collamer lens(TICL).METHODS: A total of 60 patients(115 eyes)with moderate to high astigmatism in myopia(115 eyes)from June 2019 to June 2021 and treated in the refractive center of Heyuan Aier Eye Hospital were enrolled in the study, then were divided into Group A and Group B according to the operations they would accept. There were 32 patients(62 eyes)in the Group A treated with corneal topography-guided FS-LASIK and 28 patients(53 eyes)in the Group B treated with TICL implantation. Uncorrected visual acuity(UCVA), best corrected visual acuity(BCVA), spherical diopter and residual astigmatism were recorded preoperatively and postoperatively at 3mo, surgical safety and efficacy were evaluated, and the Alpins vector analysis was used to evaluate the astigmatism.RESULTS: The postoperative at 3mo, there were no differences in the safety index(1.163±0.167 vs 1.136±0.194)and the efficacy index(1.145±0.159 vs 1.123±0.196)between the patients of the two groups(P>0.05). However, the astigmatism vector analysis showed that there were statistically differences in the index of success index [0.125(0.091, 0.200)vs 0.200(0.167, 0.250)], the correction index [1.000(0.902, 1.066)vs 0.834(0.783, 0.869)] and the flattening index [1.000(0.922, 1.079)vs 0.835(0.795, 0.870)](P<0.01).CONCLUSION:Corneal topography-guided FS-LASIK and TICL implantation were effective and safe in correcting myopia with moderate to high astigmatism, and corneal topography-guided FS-LASIK perform better than TICL implantation for the astigmatism correction.
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@#AIM:To evaluate the effect of higher-order aberrations(HOAs)after topography-guided and wavefront-optimized femtosecond laser-assisted <i>in situ</i> keratomileusis(FS-LASIK). <p>METHODS: We searched on PubMed, the Cochrane Library, Medline, CNKI, CBM, VIP and WanFang Data database for randomized controlled trials(RCTs)and comparative studies(CTs). The published languages were limited to Chinese and English. The risk bias tool provided by the Cochrane cooperation scale and Newcastle-Ottawa Scale were used to assess the risk bias of included studies of RCTs and CTs. The published biases of included studies were assessed by the Egger test. Meta-analysis was performed with Review Manager 5.4.<p>RESULTS: Two randomized controlled trials and six comparative studies with a total of 987 subjects were included(482 in the topography-guided FS-LASIK group, 505 in the wavefront optimized FS-LASIK group). The Meta-analysis showed that the topography-guided group has a better effect than the wavefront-optimized group in spherical equivalent, the difference between the two groups was statistically significant \〖<i>WMD</i>=0.11, 95%<i>CI </i>(0.07, 0.14), <i>P</i><0.00001\〗. And the results also indicated that there was a significant difference between the two groups with HOAs \〖<i>WMD= </i>-0.09, 95%<i>CI </i>(-0.13,-0.05), <i>P</i><0.0001\〗, spherical aberrations \〖<i>WMD=</i>-0.05, 95%<i>CI </i>(-0.09, -0.01), <i>P</i>=0.008\〗 and coma \〖<i>WMD=</i>-0.08, 95%<i>CI </i>(-0.12, -0.05), <i>P</i><0.00001\〗.<p>CONCLUSION: Based on the available evidence, topography-guided FS-LASIK has higher diopter and lower HOAs, spherical aberrations and coma than wavefront-optimized FS-LASIK.
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Purpose: To compare the visual outcomes and higher order aberrations (HOAs) following wavefront optimized (WFO) laser in situ keratomileusis (LASIK) versus topography-guided customized ablation (TCAT) LASIK for myopia and myopic astigmatism. Methods: Patients who underwent femtosecond-assisted LASIK for myopic correction between August 2016 and October 2017 were included in this interventional prospective case series. The following parameters were evaluated preoperatively and at 3 months' postoperative visit: uncorrected distance vision acuity (UDVA) and corrected distance vision acuity (CDVA), manifest refraction, and HOAs. Results: Two hundred eyes of 100 patients were included in the study. At 3 months' postoperative visit, 92% and 90% eyes in the TCAT and WFO groups, respectively, demonstrated a UDVA of 20/20 or better (P = 0.90). A residual manifest spherical equivalent within 0.5 D was achieved in 100% and 95% of the eyes in the TCAT and WFO groups, respectively (P = 0.10). No significant difference was observed in the HOAs induced in both the groups, with slightly lower induction of trefoil and horizontal coma in the TCAT group. Conclusion: Both groups demonstrated similar refractive efficacy and predictability, with greater gain of CDVA following TCAT ablation. HOAs induced were not significantly different between the two groups. Further studies are needed to validate the superiority of one procedure over the other.
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Purpose: To compare the outcome of Collagen cross‑linking (CXL) with that following topography‑guided customized ablation treatment (T‑CAT) with simultaneous CXL in eyes with progressive keratoconus. Materials and Methods: This was a prospective, non‑randomized single centre study of 66 eyes with progressive keratoconus. Of these, 40 eyes underwent CXL and 26 eyes underwent T‑CAT + CXL. The refractive, topographic, tomographic and aberrometric changes measured at baseline, 1, 3 and 6 months post‑operatively were compared between both groups. Results: After a mean follow‑up of 7.7 ± 1.3 months, the mean retinoscopic cylinder decreased by 1.02 ± 3.16 D in the CXL group (P = 0.1) and 2.87 ± 3.22 D in the T‑CAT + CXL group (P = 0.04). The Best corrected visual acuity increased by 2 lines or more in 10% of eyes in the CXL group and in 23.3% of eyes in the T‑CAT + CXL group. The mean steepest‑K reduced by 0.40 ± 3.71 D (P = 0.77) in the CXL group and by 2.91 ± 2.01D (P = 0.03) in the T‑CAT + CXL group. The sag factor and surface asymmetry index showed no significant change in the CXL group but reduced by 3.59 ± 5.94 D (P = 0.01) and 0.72 ± 1.18 (P = 0.02) respectively in the T‑CAT + CXL group. There was a significant increase in the highest posterior corneal elevation in both groups (9.57 ± 14.93 μ in the CXL group and 7.85 ± 9.25 μ in the T‑CAT + CXL group, P ≤ 0.001 for both). There was significantly greater reduction of mean coma (P < 0.001) and mean higher‑order aberrations (P = 0.01) following T‑CAT + CXL compared to CXL. Conclusions: CAT + CXL is an effective approach to confer biomechanical stability and to improve the corneal contour in eyes with keratoconus and results in better refractive, topographic and aberrometric outcomes than CXL alone.
ABSTRACT
Keratoconus is a progressive ectatic disorder of the cornea which often presents with fluctuating refraction and high irregular astigmatism. Correcting the vision of these patients is often a challenge because glasses are unable to correct the irregular astigmatism and regular contact lenses may not fit them very well. Topography-guided custom ablation treatment (T-CAT) is a procedure of limited ablation of the cornea using excimer laser with the aim of regularizing the cornea, improving the quality of vision and possibly contact lens fit. The aim of the procedure is not to give a complete refractive correction. It has been tried with a lot of success by various groups of refractive surgeons around the world but a meticulous and methodical planning of the procedure is essential to ensure optimum results. In this paper, we attempt to elucidate the planning for a T-CAT procedure for various types of cones and asphericities.