|
 
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| ORIGINAL ARTICLE |
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| Year : 2023 | Volume
: 116
| Issue : 1 | Page : 15-23 |
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Toric implantable phakic contact lens versus bioptics for the correction of moderate to high myopia and astigmatism
Amr A Elbakry, Rania M Sobhi, Ahmed Hassanein, Hoda T El Shiwy
Department of Ophthalmology, Faculty of Medicine, Cairo University, Cairo, Egypt
| Date of Submission | 12-Dec-2022 |
| Date of Decision | 17-Dec-2022 |
| Date of Acceptance | 18-Dec-2022 |
| Date of Web Publication | 30-Mar-2023 |
Correspondence Address:
MBBCh, MSc, MD Hoda T El Shiwy
Department of Ophthalmology, Faculty of Medicine, Kasr Al Ainy Hospitals, Cairo University, PC 11559, Cairo
Egypt
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/ejos.ejos_116_22
Purpose To compare refractive and visual outcomes and patient satisfaction of toric implantable phakic contact lens (T-IPCL) versus bioptics (IPCL followed by femtosecond laser assisted in-situ keratomileusis) in myopia (moderate to high) with astigmatism.
Patients and methods A total of 13 eyes underwent T-IPCL implantation, and 11 eyes were corrected using bioptics. Complications, uncorrected and corrected distance visual acuities, refraction, safety, efficacy, predictability, tear-film break-up time, contrast sensitivity, and patient satisfaction were assessed 6 months postoperatively.
Results No complications were reported. Mean spherical equivalent was −0.62±0.49 D in T-IPCL and −0.55±0.26 D in the bioptics group (P=0.464). In 10 (76.9%) eyes of T-IPCL and 11 (100%) eyes of bioptics, the spherical equivalent and astigmatism were within ±1 D, respectively. A significantly better astigmatic correction was demonstrated in the bioptics group as confirmed by vector analysis (P<0.001). Loss of lines was not reported; both uncorrected and corrected distance visual acuities improved significantly (P<0.05), with no significant differences (P>0.05). Safety indices were 1.15±0.08 and 1.1±0.09 and efficacy indices were 1.04±0.11 and 1.03±0.06 in T-IPCL and bioptics groups, respectively, which were insignificant. The contrast sensitivity and tear-film break-up time were significantly better in the T-IPCL group (P<0.001). Distant vision satisfaction was better in the bioptics group, whereas glare, halos, and dry eye satisfaction were better in the T-IPCL group (P<0.05).
Conclusion Both T-IPCL and bioptics can successfully correct moderate to high myopia with astigmatism. The T-IPCL carries better optical quality with less glare, halos, and dry eye. Bioptics gives better astigmatic correction and distant vision satisfaction but carries the risk of a second surgical intervention.
Keywords: astigmatism, implantable phakic contact lens, moderate and high myopia, toric and spherical phakic intraocular lens
How to cite this article:
Elbakry AA, Sobhi RM, Hassanein A, El Shiwy HT. Toric implantable phakic contact lens versus bioptics for the correction of moderate to high myopia and astigmatism. J Egypt Ophthalmol Soc 2023;116:15-23 |
How to cite this URL:
Elbakry AA, Sobhi RM, Hassanein A, El Shiwy HT. Toric implantable phakic contact lens versus bioptics for the correction of moderate to high myopia and astigmatism. J Egypt Ophthalmol Soc [serial online] 2023 [cited 2023 May 30];116:15-23. Available from: http://www.jeos.eg.net/text.asp?2023/116/1/15/372943 |
| Introduction | |  |
Refractive surgery currently offers different options for correcting astigmatism and myopia. Based on the degree of the error, excimer laser procedures are reserved for low to moderate myopia, whereas for higher degrees, the phakic intraocular lens (pIOL) is used to avoid breeching the safety limits of corneal treatment [1],[2]. Meanwhile, in correcting myopic astigmatism, both excimer laser and toric pIOLs have been found to be competent [3],[4],[5],[6]. Laser assisted in-situ keratomileusis (LASIK) was an effective technique for correcting astigmatism up to 4.5 D [4], whereas pIOLs in the form of the toric implantable collamer lens (T-ICL) provided great results for astigmatism [7],[8],[9],[10] for up to 7 D [6].
The toric implantable phakic contact lens (T-IPCL V2) was found to provide refractive and visual results similar to the results when using T-ICL, with comparable predictability and stability [11].
Zaldivar et al. [12], who used excimer laser following pIOL implantation to treat myopia with astigmatism, pioneered ‘Bioptics’, which is the combination of refractive surgical procedures to correct refractive errors. Bioptics has demonstrated [13],[14],[15],[16] greater predictability and comparable safety and efficacy profile when compared with sole pIOL implantation. Fewer studies have directly compared T-ICL implantation and bioptics [17],[18].
This study compared refractive and visual outcomes as well as patient satisfaction for T-IPCL versus bioptics [spherical IPCL combined with femtosecond laser assisted in-situ keratomileusis (FS-LASIK)] in the treatment of moderate to high myopia with astigmatism.
| Patients and methods | | |
Design
A retrospective analytic study was conducted that included the right eyes of 24 patients diagnosed with myopia and astigmatism, which were operated on at the International Eye Hospital (Cairo, Egypt) during September 2021 till February 2022 by the same surgeon Amr Ahmad Elbakry (A.B.). A total of 13 eyes were randomly treated by T-IPCL, and the other 11 eyes underwent spherical IPCL implantation followed by FS-LASIK 6–12 weeks later.
This study adhered to the tenants of Helsinki declaration. All surgical procedures and possible complications were thoroughly explained to all patients, and a written informed consent was taken from each patient before the study. All patients’ personal data were confidential. The study was granted the Cairo University scientific committee approval and the approval of the ethical committee of International Eye Hospital.
Inclusion criteria
Patients between 20 and 40 years of age, with a myopia greater than −8 D, a myopic astigmatism more than −3 D, stable refraction for at least 1 year, and at least 2 weeks without wearing contact lenses before surgery were included. Any individual with a corrected distant visual acuity (CDVA) of 6/18 (0.5 LogMAR) or better, a minimum anterior chamber depth (ACD) more than or equal to 2.9 mm, a minimal endothelial cell density (ECD) of 2000 cell/mm, an anterior chamber angle grade II or more by gonioscopic examination, and those who were free of any systemic or ocular pathology and had no history of prior ophthalmic interventions/ surgeries were also included in this study.
Exclusion criteria
Patients with unstable refraction, history of intraocular inflammation or eye disease other than the refractive error, pregnancy, or using any form of hormones, antipsychotics, or antidepressants were excluded.
Preoperative evaluation and assessment
A complete ocular examination was done on all patients before surgery, which included uncorrected (UDVA) and CDVA, manifest and cycloplegic refraction, intraocular pressure (IOP) measurement using applanation tonometry, slit-lamp examination, gonioscopy, and fundus examination. Corneal mapping, ACD, white-to-white diameter, and pupillary size were carried out using the Pentacam (Scheimpflug Camera, Pentacam HR; Oculus Optikgerate GmbH, Heidelberg, Germany). Assessment of ECD was performed using a noncontact specular microscope (Tomey EM-3000, Phoenix, AZ, USA). Tear film break-up time (TBUT) was measured.
IPCL parameters (power and length) were measure via the online IPCL calculator provided by the manufacturer. The keratometric readings, ACD, and pachymetry were outcomes recoded for the purpose of estimating IPCL power, whereas white-to-white and the ACD were used to determine IPCL length. Pentacam was repeated in the bioptics group 6–12 weeks following initial surgery and before the FS-LASIK surgery.
The implantable phakic contact lens
The IPCL (V2; Care Group Sight Solutions, Dabhasa, Gujarat, India) is made up of a hydrophilic acrylic substance, with a central hole in its optic (380 μm) designed to minimize glare and scattering of light and can be inserted in the eye through 2.8-mm incision. There are 11 perforations to ensure proper aqueous flow; four holes in the haptic plate, one in the optic center, four in the periphery of the optic, two at the left side of the optic (with the lens facing up) to facilitate correct positioning during implantation, and six haptics for increased stability. The available powers range from −4 to −30 D, and from +1 to +15 D in 0.5 D steps, and up to −10 D cylinder in the toric type. The lens diameter is 6.60 mm and could be customized up to 7.50 mm. The lens has a refractive index of 1.465 and is available in several sizes from 11 to 14 in 0.25 mm steps [19] ([Figure 1]).
Intervention
One surgeon performed all surgeries (A.B.) using local anesthesia through a 2.8-mm incision with horizontal positioning of the lens. In both groups, the aim was to fully correct the spherical error and slight undercorrection of the astigmatism (target cylinder −0.25).
In the T-IPCL group, to maintain supine position and control any potential cyclotorsion, the zero horizontal axis was marked at the three and nine-o’clock limbus, which were marked preoperatively with a marking pen while the patient sat upright during slit-lamp examination. The lens axis was confirmed intraoperatively under a microscope with a Mendez-type axis ring marker (Asico, Westmont, Illinois, USA).
In the bioptics group, FS-LASIK was carried out at an average period of 6–12 weeks after IPCL implantation to correct the myopic astigmatism and any residual error by means of Visumax Femtosecond laser and MEL-90 excimer laser (Carl Zeiss Meditec, Jena, Germany). A superiorly hinged 90-μm-thick flap with a diameter of 7.5–8.0 mm and an optical zone between 6 and 7 mm was used. A standard (nonwavefront) ablation profile was used to correct the refractive cylinder and any residual sphere with the active eye tracker on. Again, the patient was marked preoperatively at the three- and nine-o’clock limbus via a marking pen and compared with the zero axis during the procedure, and if any misalignment was detected, the patients’ head was rotated.
Postoperative examination and follow-up
Patients were examined day 1, 1 week, 1 month, 3 months, and 6 months postoperatively. At 6 months, the same series of examinations that were performed preoperatively were repeated. Pentacam was used to assess the vault of the IPCL whether spherical or toric to ensure its safety within the suitable range of 250–750 μm [20].
Outcome measures
Any intraoperative or postoperative complications were reported. At 6 months, UCVA, DCVA, safety index (preoperative and postoperative CDVA), efficacy index (postoperative UCVA and preoperative CDVA), and the refraction and predictability of refractive outcomes were examined. Photopic contrast and sensitivity were examined using a Pelli-Robson illuminated chart. TBUT and ECD were measured. A subjective questionnaire was given to all patients regarding their distance and night vision, halos, glare, dry eye sensation, and their overall satisfaction about the surgery. A score from 0 to 100 was given, where 100 points were the best ([Figure 2]).
Statistical analysis
Data were managed and analyzed using the Statistical Package for the Social Sciences (IBM Corp. Released 2021. IBM SPSS Statistics for Windows, Version 28.0.; IBM Corp., Armonk, New York, USA). Numerical data were summarized using means, SDs, and ranges. Categorical data and frequency estimated were summarized as numbers and percentages. Normality of numerical data was assessed using Kolmogorov–Smirnov test and Shapiro–Wilk test. χ2 or Fisher’s tests studied comparisons between the independent groups with respect to categorical data, as appropriate. Similarities between both groups for normally distributed numeric variables were analyzed using the Student t test, and for non-normally distributed numeric variables, comparisons were done by Mann–Whitney test. All tests were two tailed, and P value less than or equal to 0.05 was considered significant.
| Results | | |
The T-IPCL group had eight (61.5%) females and five (38.5%) males, with a mean age of 22±7 years (3–32). The bioptics group included six (54.5%) females and five (45.5%) males with a mean age of 24±3 years (20–29) ([Table 1]). The preoperative UDVA [1.3±0.1 LogMAR (1.1–1.4) and 1.3±0.2 LogMAR (1–1.5), respectively] and the preoperative CDVA [0.6±0.1 LogMAR (0.3–0.8) and 0.5±0.2 LogMAR (0.2–0.7), respectively] were appropriately matched between both groups, with no significant differences (P=0.976 and 0.135, respectively) ([Table 4]). No intraoperative or postoperative complications were reported in both groups, and the vault of the lens was within the safety limits, and excessive rotation was not detected in any of the cases. No dehiscence was found in the IPCL incision or decentration of the lens after FS-LASIK treatment in the bioptics group. | Table 1 Demographic and preoperative IPCL choice parameters of the two groups
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Refractive outcome
The two groups were properly matched regarding the preoperative spherical equivalent (SE) [−14.08±1.69 D (−17.5 to −11.6) in the T-IPCL group compared with −15±3.45 D (−20.75 to −9.5) in the bioptics group; P=0.467]. Moreover, the preoperative astigmatic error was slightly higher in the T-IPCL group, with a mean of −4.17±0.95 D (−6 to −3), as compared with −3.66±0.74 D (−5.5 to −3) in the bioptics group, which was considered not significant (P=0.134) ([Table 1]).
After 6 months, the postoperative refractive SE was comparable in both groups. The SE mean in the T-IPCL group was −0.62±0.49 D (−1.12 to 0.25) and −0.55±0.26 D (−1 to −0.12) in the bioptics group, with insignificant differences (P=0.464). The predictability of SE correction was greater in the bioptics group (100% within 1 D) in comparison with the T-IPCL group (76.9% within 1 D) (P=0.223) ([Table 2]).
Nevertheless, correction of astigmatism was in favor of the biotics group, with a mean of −0.41±0.17 D (−0.75 to −0.25), with a statistically significant difference compared with the T-IPCL group, which had a mean of −0.9±0.33 D (−1.5 to −0.5) (P<0.001) ([Table 2]). Moreover, the predictability of astigmatic correction was similar to SE correction, being more favorable in the bioptics group (100% within 1 D) when compared with the T-IPCL group (76.9% within 1 D), and the difference was statistically insignificant as well (P=0.223) ([Table 2]).
Using the Alpins method [21],[22], vector analysis demonstrated that the mean target-induced astigmatism (TIA) in the T-IPCL group was 3.92±0.95 (2.75–5.75) and in the bioptics group was 3.41±0.74 (2.75–5.25), which was insignificant (P=0.134). Likewise, the surgical induced astigmatism (SIA) in the T-IPCL group was 3.27±0.72 (2.5–4.75) and in the bioptics group was 3.25±0.8 (2.5–5.25) (P=0.918). On the contrary, the difference was significant and better in the bioptics group regarding the difference vector (DV) magnitude of error (DV=SIA–TIA), correction index (CI=SIA/TIA), and the index of success (IOS=DV/TIA) (P<0.001). The mean angle of error in the T-IPCL group was 1.2±5.8 (−10 to 10) and in the bioptics group was −0.02±0.07 (−0.09 to 0.17) (insignificant difference; P=0.730) ([Table 3]). | Table 3 Vector analysis of astigmatic correction in the two groups using the Alpins method
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Visual outcome
No loss of lines was reported for both the T-IPCL and bioptics groups, with a significant improvement of both UCVA (P<0.001) and DCVA (P<0.001 and 0.004; respectively) when compared with the preoperative data. In the T-IPCL, all patients (100%; n=13) gained one or two lines of CDVA, whereas nine (81.8%) patients in the bioptics group gained the same, and the remaining two patients retained the same CDVA. In the T-IPCL group, the postoperative UCVA was 0.5±0.2 LogMAR (0.2–0.8), whereas the postoperative CDVA was 0.3±0.1 LogMAR (0.2–0.5). In the bioptics group, the postoperative UCVA was 0.4±0.1 LogMAR (0.2–0.6) and the CDVA postoperatively was 0.3±0.1 LogMAR (0.2–0.5). The postoperative UDVA and CDVA were similar for both groups and insignificant (P=0.116 and 0.391, respectively). The safety index mean for the T-IPCL group was 1.15±0.08 (1.06–1.33), whereas in the bioptics group was 1.1±0.09 (1–1.31). The mean efficacy index in the T-IPCL group was 1.04±0.11 (0.92–1.33) and 1.03±0.06 (0.94–1.15) in the bioptics group. The differences were statistically insignificant regarding the safety and efficacy indices (P=0.130 and 0.867, respectively) ([Table 4]).
Contrast sensitivity
The mean contrast sensitivity improved in the T-IPCL group from 1.64±0.26 (1.25–2) to 1.7±0.19 (1.4–2), with a percentage improvement of +4.49±9.3% (−8.82 to 21.43). Contrast sensitivity worsened in the bioptics group from 1.82±0.19 (1.55–2.15) to 1.58±0.23 (1.25–2) with a percentage decrease of −13.57±7.52% (−24.32 to 0). The change in percentage was significant (P<0.001), and it was in favor of the T-IPCL group ([Table 5]). | Table 5 Preoperative and postoperative contrast sensitivity, endothelial cell density, and tear-film break-up time changes in the two groups
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Endothelial cell density
The mean ECD decreased in both groups, with −11.56±3% (−16.8 to −6.13) in the T-IPCL group, and −13.33±3.19 (−19.03 to −9.06) in the bioptics group. The difference in change percentage between both groups was insignificant (P=0.303) ([Table 5]).
Dry eye
TBUT scores were significantly lowered in the bioptics group from 12±1 (10–14) to 9±1 (8–11), with a percentage decrease of −21.31±10.65% (−38.46 to −9.09). The scores were better in the T-IPCL group, with a much lesser decrease from 12±1 (10–14) to 11±1 (10–13), with a percentage decrease of −4.89±5.28% (−16.67–0). The difference in TBUT change was significant (P<0.001) and in favor of the T-IPCL group ([Table 5]).
Subjective questionnaire satisfaction results
Even though distant vision satisfaction was significantly better in the bioptics group (P=0.009), the complaints about halos, glares, and dry eye were significantly better in the T-IPCL group (P<0.001). Night vision and overall satisfaction were comparable in both groups, with statistically insignificant differences (P=0.277, 0.208, respectively) ([Table 6]). | Table 6 Satisfaction results in the two groups according to the subjective questionnaire
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| Discussion | | |
Observing and documenting visual and refractive results after T-ICL were conducted in various studies [7],[8],[9],[10]. Likewise, some studied similar outcomes for bioptics [12],[13],[15],[16]. Both were found to be safe, effective, and predictable in alleviating myopic astigmatism (moderate to high). Minimal studies directly compared T-ICL results with bioptics [17],[18]. Recently, T-IPCLs were noted to be as effective in managing high myopic astigmatism [11],[23]. We compared refractive and visual outcomes along with patient satisfaction 6 months after T-IPCL implantation versus bioptics in the form of IPCL followed by FS-LASIK. No complications were reported intraoperatively or postoperatively. In a T-ICL clinical study [7], complications included T-ICL rotation, vaulting problems, and clinically significant lens opacity. None of our cases required toric pIOL repositioning.
In the current study, visual results were satisfactory overall, thereby suggesting that both interventions are of value in the correction of myopia (moderate to high) with astigmatism. In both groups, following 6 months, the UDVA and CDVA significantly improved when compared with the preoperative results (P>0.05), and none of the patients lost any line of corrected vision; in fact, most of the patients gained one or two lines. The postoperative UDVA and CDVA and safety and efficacy indices were comparable between T-IPCL and bioptics, with statistically insignificant differences (P>0.05). Refractive results are used to determine if there are good visual outcomes following surgery, which in this study was demonstrated by postoperative refractive SE, and this outcome was comparable for both groups. The mean SE in the T-IPCL group was −0.62±0.49 and −0.55±0.26 D in the bioptics group, with statistically insignificant difference (P=0.464). Both groups showed similar predictability of SE correction, with a statistically insignificant difference (P=0.223).
Astigmatic correction was better in the biotics group, with a mean of −0.41±0.17 D, compared with the T-IPCL group, with a mean of −0.9±0.33 D (−1.5 to −0.5) (P<0.001). Moreover, the predictability of astigmatic correction was greater in the bioptics group (100% within 1 D) when compared with the bioptics group (76.9% within 1 D) (P=0.223). The better astigmatic correction in the bioptics group can be explained by the fact that slight cyclotorsion may occur with T-IPCLs. This can be confirmed by the angle of error [24],[25] in both groups when using the vector analysis by the Alpins method. In the T-IPCL group, bigger angles of error were detected (range −10 to 10°) when compared with a range of negative five to five degrees in the bioptics group. This was again confirmed by the significantly better DV magnitude, CI, and IOS in the bioptics group (P<0.001) despite the similarities between the two groups regarding TIA and SIA (P>0.05). Another explanation is the preoperative marking and the active eye tracker software located within the MEL-90 excimer laser [26], which may have led to mildly better results of astigmatic correction in the bioptics group. Similarly, Ganesh et al. [27] mentioned that T-ICL results depend upon some factors, including preoperative proper sizing and marking to avoid postoperative significant rotation (>20°). They needed to exchange two lenses in their study due to excessive rotation. As already mentioned, all our cases had a safe and ideal vault, and thus, excessive rotation did not happen, and even with the slightly worse astigmatic results for the T-IPCL group in this study, still the SE and the visual acuity were comparable in both groups.
Like our study, Alfonso and colleagues compared T-ICL with bioptics. The postoperative UDVA was similar, but CDVA was statistically better in the T-ICL group (P=0.016). The safety index was similar, but the bioptics group had a higher efficacy index (0.98±0.20 vs. 1.09±0.19, respectively, P<0.001). They attributed the better efficacy index in the bioptics to the small residual uncorrected astigmatism of about 1.0 D, which was demonstrated in the T-ICL group as a result of a slight misalignment of the T-ICL. They reported excellent comparable predictability in both groups as the postoperative SE improved from a mean −6.62±2.83 to −0.15±0.36 D in T-ICL group and −10.61±3.27 to −0.08±0.26 D in bioptics group, with 81.5 and 94.0% within ±0.50 D of the predicted refraction in the T-ICL and bioptics, respectively [18].
Similarly, Jabbour and Bower followed their bioptics patients for 3 years. Preoperative UDVA was 2.29±0.46 LogMAR and improved to 0.03±0.23 LogMAR (P<0.05), whereas the SE mean was −12.30±4.05 and reached −0.21±0.46 at 3-year follow-up (P<0.05). The safety and efficacy indices were 1.47±0.27 and 1.28±0.32, respectively. Vault-related issues led to the exchange of two lenses. They concluded that bioptics had great long-term safety profile and predictable and efficient outcomes for high myopic astigmatism, which makes it an excellent alternative to the toric pIOL. The ECD loss was 5.7% at 12 months [28]. In the current study, the mean ECD decreased in both groups (T-IPCL; 11.5%, bioptics; 13.3%). Differences in percentage between both groups were statistically insignificant (P=0.303).
Igarashi et al. [29] demonstrated insignificant contrast sensitivity changes following ICL implantation, but there was a significant reduction following FS-LASIK. Ganesh et al. [27] documented that after 1 year, significantly better mean photopic contrast sensitivity scores were demonstrated in the T-ICL group, while being significantly lower in the FS-LASIK group. This coincided with our results, as the mean contrast sensitivity improved in the T-IPCL group (+4.49±9.3%) and was worse in the bioptics (−13.57±7.52%), and the difference was significant (P<0.001).
In the current study, a marked decrease in TBUT scores was seen in the bioptics group (−21.31±10.65%). The scores were better in the T-IPCL group (−4.89±5.28%), and the difference in TBUT change was statistically significant (P<0.001). Previous studies on postoperative dry eye after FS-LASIK matched our results [30],[31]. Similarly, Ganesh et al. [27] showed that postoperative dry eye was significantly worse with FS-LASIK than with T-ICL. They attributed this to the higher disruption of corneal nerve fibers with FS-LASIK.
The pervious findings explain the satisfactory results reported in this study. The optical quality of T-IPCL was far better than bioptics, as the complaints about halos, glares, and dry eyes were significantly better (P<0.001). On the contrary, distant vision satisfaction was significantly better in the bioptics group (P=0.009) owing to the better focus achieved with better astigmatic correction. The results were almost equal in terms of night vision and overall satisfaction for both groups, with statistically insignificant differences (P=0.277 and 0.208, respectively).
When extensively searching the literature, we notice that this is the first study to directly compare T-IPCL verses bioptics results.
Limitations of the study
The study has a small sample size and a short follow-up duration, which suggests the need for bigger samples and longer postoperative follow-up evaluation in future studies to affirm the current results.
| Conclusion | | |
Both T-IPCL and bioptics can be successfully used in the correction of moderate to high myopia with astigmatism. Each approach has its own pros and cons. The T-IPCL carries better optical quality in the form of less glare, halos, and dry eye, whereas bioptics demonstrates better astigmatic correction and distant vision satisfaction but carries the risk of a second surgical intervention.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]
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