Radial keratotomy: background and how to manage these patients nowadays.

In this review, we presented the principles of radial keratotomy (RK), its evolution, enhancement, and complications, and strategies to manage the consequences of RK in the present day. It is essential to understand the RK procedure f, the theoretical background that supported this surgery, the current effect on the cornea, and how to approach patients needing vision improvement. These patients are developing cataracts that need to be handled well, from the IOL calculation to the surgical procedure. Guided keratorefractive surgery is the most accurate procedure to improve these patient's vision and life. Nevertheless, some patients may need other approaches, such as sutures, penetrating keratoplasty, corneal rings, and pinhole implants, depending on the degree of irregularity of the cornea, ablation depth for guided surgery or if the sutures are open.

Long-Term Corneal Refractive Power Changes Two Decades After Radial Keratotomy With Microperforations.

ABSTRACT: We retrospectively examined corneal refractive power in three patients who had been followed up for more than 20 years after radial keratotomy (RK) with microperforations (MPs). All patients underwent RK in both eyes and were referred to our clinic because of postoperative decreased vision. MP was observed in five of the six eyes at the initial visit. The corneal refractive power of the anterior and posterior surfaces of the 6-mm-diameter cornea was examined using Fourier analysis based on corneal shape analysis using anterior segment optical coherence tomography. The spherical components decreased in all three cases. The asymmetry and higher-order irregularity components and fluctuations in corneal refractive power were markedly greater in the two cases with MP in both eyes. Fluctuations in corneal refractive power were observed at more than 20 years after RK with MP. Therefore, careful observation is necessary, even after a long-term postoperative follow-up period.

[Implantation of a monofocal intraocular lens after femtosecond laser intrastromal keratotomy and contralateral implantation of a trifocal IOL: a case report].

An age-related cataract patient who underwent femtosecond laser intrastromal keratotomy in the right eye for presbyopia correction 8 years ago was subjected to femtosecond laser-assisted phacoemulsification, with implantation of a monofocal intraocular lens (IOL) and a trifocal IOL in the right and left eyes, respectively. The corneal stromal ring was complementary to the monofocal IOL, which recovered the distance and near visual acuity, in the right eye postoperatively. The trifocal IOL provided good intermediate visual acuity for the left eye. The vision of the patient reached an ideal level for all visual distances. The binocular fusion was within the normal range, and the stereoscopic vision was restored. We hope that this case report can act as a reference for the treatment of cataract after presbyopia corrective surgery.

Double safe suture during cataract surgery on post radial keratotomy patients using clear corneal incisions.

PURPOSE: the aim of this study is to find a safer surgical approach in cataract surgery on eyes previously treated with radial keratotomy using clear corneal incisions. SETTING: Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Ophthalmology Clinic, University of Messina, Messina, Italy. DESIGN: Prospective study. METHODS: A prospective study was conducted on a group of 20 patients, 21 eyes with 16 RK incisions were evaluated for cataract phacoemulsification. Samples were divided into two groups: Group 1 underwent surgery with pre-operative one corneal stitch along radial keratotomy incisions near the main access site whereas Group 2 underwent modified surgery with two corneal stitches. RESULTS: After surgery, visual acuity, corneal hysteresis and corneal strength was evaluated. In all cases, an increased visual acuity was observed. Group 1 showed an UCVA of logMAR 0.22 ± 0.14, while group 2 presented a logMAR of 0.1 ± 0.07. Data did not show a statistically significant difference in UCVA after surgery between the two groups (P = 0.133). Instead, a significant difference in corneal hysteresis (CH), respectively with values of 8.65 ± 1.6 mmHg in group 1 and 9.2 ± 1.8 in group 2 (P = 0.031), and a corneal resistance factor (CRF) with values of 7.87 ± 1.4 mmHg in the first group and 8.65 ± 1.6 mmHg in the second one (P = 0.039) was observed. CONCLUSIONS: Double safe suture technique offers better stabilization of corneal structure during surgery in patients preventively treated with 16 incisions RK.

Cataract surgery outcomes in eyes with previous radial keratotomy.

BACKGROUND/OBJECTIVES: This study shows the visual and refractive outcomes of cataract surgery in patients with previous radial keratotomy (RK). SUBJECTS/METHODS: This is a retrospective case series of 100 eyes (65 patients) with previous RK who had undergone routine cataract surgery with a monofocal intraocular lens implant (IOL) at Moorfields Eye Hospital, London, United Kingdom, between January 2004 and December 2018. RESULTS: Mean age at the time of surgery was 59.8 years; 39% eyes had ocular copathology. Best-corrected visual acuity (LogMAR; median, interquartile range) improved from 0.30 (0.22, 0.55) to 0.06 (-0.02, 0.21) in eyes without copathology, and from 0.56 (0.30, 1.00) to 0.20 (0.00, 0.20) in eyes with copathology. Haigis formula (19 eyes) resulted in a median prediction error of -0.31 D (-1.07, +0.05), versus -0.55 D (-1.23, +0.22) for Double-K SRK/T (55 eyes) and +0.93 D (0.20, 2.31) for SRK/T (18 eyes). At the final follow-up, 52.6% eyes were within 0.5 D and 68.4% within 1 D of the predicted spherical equivalent for Haigis, versus 32.7% and 52.7% for Double-K SRK/T, and 27.8% and 38.9% for SRK/T. The most frequent complication was RK incision dehiscence (8%). CONCLUSIONS: Although the best-corrected visual acuity outcomes compare with the UK national benchmarks, significantly fewer eyes with previous RK achieved the level of unaided distance visual acuity to allow spectacle independence. Surgeons should be aware of the increased likelihood of wound dehiscence and plan surgery accordingly. Haigis formula tended to have a better predictability of the postoperative spherical equivalent and, since introduced, was the preferred choice for IOL calculation in this group of patients.

Fórmula Barrett True K en pacientes con catarata operados de cirugía refractiva corneal / The Barrett True-K formula in cataract patients undergoing corneal refractive surgery

Objetivo: Determinar los resultados refractivos en pacientes operados de catarata con cirugía refractiva corneal, según el cálculo del poder dióptrico de la lente intraocular con la fórmula Barrett True K. Métodos: Se realizó un estudio pre-experimental, del tipo antes y después, en el cual fueron incluidos 18 pacientes (31 ojos). En ellos se analizaron variables demográficas y clínicas. La principal variable de salida fue la predictibilidad del componente esférico ± 0,50 D, ± 1,0 D según la longitud axial. Resultados: Fueron estudiados pacientes con un promedio de edad de 59,4 años, predominantemente del sexo femenino (66,7 por ciento). El 77,4 por ciento fue operado con queratotomía radial. Con la cirugía de catarata se produjo una mejora ostensible de la agudeza visual no corregida (mediana preoperatoria: 0,12 y mediana posoperatoria: 0,60). Solo el 9,7 por ciento de los ojos analizados presentó una agudeza visual sin corregir de 20/20 y el 90,3 por ciento de 20/40 o más. La cantidad de ojos con un equivalente esférico de ± 0,50 disminuyó en la medida en que aumentó la longitud axial (corta: 100 por ciento; normal: 57,1 por ciento; larga: 22,7 por ciento), no así la predictibilidad del componente esférico de ± 0,50, que aumentó (corta: 50,0 por ciento; normal: 57,1 por ciento; larga: 63,6 por ciento). Conclusiones: La fórmula Barrett True K resulta útil para el cálculo de la lente intraocular en pacientes operados de catarata y cirugía refractiva corneal previa(AU)

Objective: Determine refractive outcomes in patients undergoing cataract corneal refractive surgery based on intraocular lens dioptric power calculation with the Barrett True-K formula. Methods: A pre-experimental before/after study was conducted of 18 patients (31 eyes). Demographic and clinical variables were analyzed. The main output variable was spherical component predictability ± 0.50 D, ± 1.0 D according to axial length. Results: Mean age was 59.4 years; female sex prevailed (66.7 percent). Of the patients studied, 77.4 percent underwent radial keratotomy. Cataract surgery led to notable uncorrected visual acuity improvement (preoperative mean: 0.12; postoperative mean: 0.60). Only 9.7 percent of the eyes examined had an uncorrected visual acuity of 20/20, whereas 90.3 percent had 20/40 or more. The number of eyes with a spherical equivalent of ± 0.50 fell as axial length rose (near: 100 percent; normal: 57.1 percent; far: 22.7 percent), unlike ± 0.50 spherical component predictability, which rose from near: 50.0 percent; normal: 57.1 percent; far: 63.6 percent. Conclusions: The Barrett True-K formula is useful for intraocular lens calculation in patients undergoing previous cataract and corneal refractive surgery(AU)

Comparison of manual and femtosecond astigmatic keratotomy in the treatment of postkeratoplasty astigmatism.

PURPOSE: To compare the outcomes of femtosecond astigmatic keratotomy (FSAK) and manual astigmatic keratotomy (AK) in treatment of postkeratoplasty astigmatism. METHODS: A retrospective, comparative, pairwise-matched case series including 150 patients who underwent either FSAK (n = 75) or manual AK (n = 75) for the treatment of astigmatism (>3.00 D) following penetrating keratoplasty or deep anterior lamellar keratoplasty. Pairwise matching for baseline variables (age, visual acuity and astigmatism) was performed. RESULTS: Mean age was 57.5 ± 16.0 years. The FSAK group had significantly better postoperative best-corrected visual acuity (BCVA) (p = 0.010), uncorrected visual acuity (UCVA) (p = 0.049), corneal astigmatism (p = 0.020) and manifest astigmatism (p < 0.001) compared with the manual AK group. Gain of ≥3 lines in BCVA (logMAR) was seen in five eyes (6.7%) and 21 eyes (28.0%) in manual AK and FSAK, respectively (p = 0.005). Alpins vector analysis showed lower (closer to 0) index of success (0.50 ± 0.24 and 0.79 ± 0.48, p < 0.001) and higher (closer to 1) correction index (0.94 ± 0.45 and 0.74 ± 0.55, p = 0.020) in FSAK compared with manual AK. Corneal and manifest astigmatism improved significantly in both groups, while BCVA and UCVA improved significantly in FSAK only. Repeat AK rate was 32% (24 eyes) in manual AK and 4% (three eyes) in FSAK (p < 0.001). Overcorrection-related re-suturing rate was 0% in manual AK and 8% (six eyes) in FSAK (p = 0.037). There was one microperforation (1.3%) in FSAK, and there were no occurrences of graft dehiscence, infectious keratitis or graft rejection. CONCLUSIONS: Both manual AK and FSAK were safe and effective in reducing postkeratoplasty astigmatism. FSAK had superior visual and keratometric outcomes compared with manual AK.

Comparison of refractive prediction for intraoperative aberrometry and Barrett True K no history formula in cataract surgery patients with prior radial keratotomy.

PURPOSE: To compare prediction errors of the Barrett True K No History (Barrett TKNH) formula and intraoperative aberrometry (IA) in eyes with prior radial keratotomy (RK). METHODS: A retrospective, non-randomized study of all patients with RK who underwent cataract surgery using IA at the UCHealth Sue Anschutz-Rodgers Eye Center from 2014 to 2019 was conducted. Refraction prediction error (RPE) for IA and Barrett TKNH was compared. General linear modelling accounting for the correlation between eyes was used to determine whether absolute RPE differed significantly between Barrett TKNH and IA. Outcome by number of RK cuts was also compared between the two methods. RESULTS: Forty-seven eyes (31 patients) were included. The mean RPEs for Barrett TKNH and IA were 0.04 ± 0.92D and 0.01 ± 0.92D, respectively, neither was significantly different than zero (p = 0.77, p = 0.91). The median absolute RPEs were 0.50D and 0.48D, respectively (p = 0.70). The refractive outcome fell within ± 0.50D of prediction for 51.1% of eyes with Barrett TKNH and 55.3% with IA, and 80.8% were within ± 1.00D for both techniques. Mean absolute RPE increased with a higher number of RK cuts (grouped into < 8 cuts and ≥ 8 cuts) for both Barrett TKNH (0.35D and 0.74D, p = 0.008) and IA (0.30D and 0.80D, p = 0.0001). CONCLUSIONS: There is no statistically significant difference between Barrett TKNH and IA in predicting postoperative refractive error in eyes with prior RK. Both are reasonable methods for choosing intraocular lens power. Eyes with more RK cuts have higher prediction errors.

Variations in keratometric values (K-value) after administration of three different eye drops - effects on the intraocular lens calculations in relation to cataract surgery.

PURPOSE: To investigate the variance in keratometric (K) values after administration of different eye drops (three tested), and the effects on intraocular lens (IOL) power calculations in relation to standard cataract surgery. METHODS: A prospective intervention study (pilot study) on 38 participants (22 women, 16 men, 58-88 years) undergoing 57 cataract surgeries. Three keratometries on each eye were performed: a baseline ('standard') keratometry about 9 weeks preoperatively, and two on the operation day; a 'dry'-measurement before interventions and a 'wet'-measurement after applying one of three eye drops (saline, Systane Ultra® , or Systane Complete® ). All standard cataract operations were uneventful. Variabilities in K-values, spherical equivalents (SEQs) for IOL power calculations (Barrett TK Universal II) and subjective manifest refractions (SRs) 6 weeks postoperatively were compared between groups. RESULTS: The 'wet' K-values had a similar variability to those of the 'standard' and 'dry' K-values (p > 0.05, anova on ranks). The mean paired differences in K-measurements between groups ranged within a small interval from -0.0107 to 0.0096 mm. After comparing the SEQ predictions with SR-measurements, the most precise IOL calculation was achieved after administration of a saline eye drop, but the precision was not statistically improved compared to the other drop modalities. CONCLUSION: The variability in K-values was not significantly changed by administration of any of the different eye drops tested, suggesting that artificial eye drops do not impact the keratometry or IOL power prediction.

Stepwise Combination of Femtosecond Astigmatic Keratotomy With Phacoemulsification and Toric Intraocular Lens Implantation in Treatment of Very High Postkeratoplasty Astigmatism.

PURPOSE: To report the outcomes of stepwise combined femtosecond astigmatic keratotomy (FSAK) and phacoemulsification with toric intraocular lens (IOL) implantation in the treatment of very high astigmatism after either penetrating keratoplasty or deep anterior lamellar keratoplasty. METHODS: This is a retrospective, interventional case series including 8 eyes of 6 patients with very high astigmatism [≥8.00 diopter (D)] after either penetrating keratoplasty or deep anterior lamellar keratoplasty who underwent FSAK, followed by phacoemulsification and toric IOL implantation. Outcome measures were corneal and manifest astigmatism and uncorrected and best spectacle-corrected visual acuity (UCVA, BSCVA). RESULTS: The average age was 58.9 ± 5.1 years. The average follow-up time was 40.9 ± 43.8 months. Outcome measure changes after both FSAK and toric IOL implantation were: corneal astigmatism improved from 13.56 ± 4.81 D to 4.48 ± 2.83 D (P < 0.001), manifest astigmatism improved from 9.15 ± 3.86 to 1.46 ± 0.88 D (P = 0.011), UCVA improved from 1.69 ± 0.45 LogMAR (Snellen equivalent ∼20/980) to 0.23 ± 0.11 LogMAR (Snellen equivalent ∼20/33, P < 0.001), and BSCVA improved from 1.01 ± 0.71 LogMAR (Snellen equivalent ∼20/200) to 0.19 ± 0.11 LogMAR (Snellen equivalent ∼20/30, P = 0.015). BSCVA and UCVA at the last follow-up were 20/40 or better in all patients. All procedures were uneventful. Two eyes underwent photorefractive keratectomy after FSAK to regularize and further reduce astigmatism before toric IOL implantation. One patient underwent temporary compression suturing because of FSAK overcorrection. CONCLUSIONS: Combined stepwise use of FSAK and phacoemulsification with toric IOL implantation was an effective and apparently safe approach in patients with very high postkeratoplasty astigmatism. Additional treatment using photorefractive keratectomy may be beneficial in some cases.

Methods for Intraocular Lens Power Calculation in Cataract Surgery after Radial Keratotomy.

PURPOSE: To compare methods of calculating the required intraocular lens (IOL) power for patients undergoing cataract surgery after radial keratotomy (RK), including the 2016 update of the True K formula. DESIGN: Retrospective case series. PARTICIPANTS: A total of 52 eyes of 34 patients who had sequential RK and cataract surgery performed in the same institution by 1 of 2 surgeons. METHODS: Seven IOL calculation formulae were evaluated: True K [History], True K [Partial History], True K [No History], Double-K Holladay 1 (DK-Holladay-IOLM), Potvin-Hill, Haigis, and Haigis with a -0.50 diopter (D) offset. Biometry was obtained with the IOLMaster 500 (Carl Zeiss Meditec AG, Jena, Germany) and Pentacam (OCULUS Inc, Arlington, WA) devices. Subjective refraction was performed at 4 to 6 weeks postoperatively. The achieved spherical equivalent outcome was compared with the target outcome to calculate the absolute error for each eye with each formula. MAIN OUTCOME MEASURES: Median absolute error (MedAE) and mean absolute error (MAE), and percentage of patients within ±0.50 D, ±0.75 D, and ±1.00 D of refractive target. Mean error (ME) was also calculated to demonstrate whether a formula tended toward more myopic or hyperopic outcomes. RESULTS: Best results were achieved with the True K [History]. The MedAE was higher (0.382 vs. 0.275) with the True K [Partial History], but a similar percentage of patients (75.0%-76.6%) achieved within ±0.50 D of target. Of the methods that do not require refractive history, the True K [No History] and unadjusted Haigis were most accurate (69.2% within ±0.50 D of target), with the True K [No History] returning the lowest MedAE but also more of a tendency toward hyperopia (ME +0.269 vs. -0.006 for Haigis). The DK-Holladay-IOLM and Potvin-Hill methods were the least accurate. CONCLUSIONS: Knowledge of the refractive history significantly improves the accuracy of IOL calculations in patients undergoing cataract surgery after previous RK. The post-RK refraction appears to be the most important parameter, with inclusion of the pre-RK refraction offering a further slight improvement in MedAE. When no refractive history is available, the True K [No History] and Haigis formulae both perform well, with the added advantage of not requiring data from separate biometric devices.

Pneumotonometer Accuracy Using Manometric Measurements after Radial Keratotomy, Clear Corneal Incisions and Lamellar Dissection in Porcine Eyes.

Purpose/Aim of the study: Measured intraocular pressure (IOP) after corneal incisions may not be reflective of the true IOP because of changes in corneal biomechanical properties. The purpose of this study is to investigate the effect of various corneal incisions on pneumotonometer accuracy in enucleated porcine eyes.Materials and Methods: A pneumotonometer was used to measure IOP (IOPp) at manometrically controlled pressure levels of 10, 20, 30 and 40 mmHg in enucleated porcine eyes. IOP measurements at each level were repeated after one of the following corneal incisions: radial keratotomy (8 eyes), lamellar dissection (10 eyes), clear cornea standard phacoemulsification incisions (10 eyes). The pneumotonometer error, defined as the difference between IOPp and manometric pressure (IOPm), was calculated for each pressure level. The error before the corneal incisions was compared to the error after the corneal incisions to assess the accuracy of the pneumotonometer.Results: The pneumotonometer underestimates true IOP at all pressure levels, both before and after the corneal procedures. There was a statistically significant greater underestimation of IOP after radial keratotomy incisions at pressure levels of 20, 30 and 40 mmHg (p = .013, 0.004, and 0.002, respectively). There was no statistically significant difference in the amount of pneumotonometer underestimation error after lamellar dissection or standard cataract incisions.Conclusion: The pneumotonometer underestimates true IOP in enucleated porcine eyes at all pressure levels between 10-40 mmHg. Radial keratotomy incisions caused a statistically significant greater underestimation error in pneumotonometry measurements at pressures of 20-40 mmHg. Lamellar dissection and clear corneal cataract incisions did not cause an additional error in pneumotonometry measurements in enucleated porcine eyes.

Optimization of surgical parameters based on patient-specific models: Application to arcuate keratotomy.

PURPOSE: To determine surgical parameters for arcuate keratotomy by simulating the intervention with a patient-specific model. SETTING: University Eye Clinic Salzburg, Paracelsus Medical University, Austria, and Institute for Surgical Technology and Biomechanics, University of Bern, Switzerland. DESIGN: Computational modeling study. METHODS: A new approach to plan arcuate keratotomy based on personalized finite element simulations was developed. Using this numeric tool, an optimization algorithm was implemented to determine the incision parameters that best met the surgeon's requirements while preserving the orientation of the astigmatism. Virtual surgeries were performed on patients to compare the performance of the simulation-based approach with results based on the Lindstrom and Donnenfeld nomograms and with intrastromal interventions. RESULTS: Retrospective data on 28 patients showed that personalized simulation reproduced the surgically induced change in astigmatism (Pearson correlation = 0.8). Patient-specific simulation was used to examine strategies for arcuate interventions on 621 corneal topographies. The Lindstrom nomogram resulted in low postoperative astigmatism (mean 0.03 diopter [D] ± 0.3 [SD]) but frequent overcorrections (20%). The Donnenfeld nomogram and intrastromal incisions resulted in a small amount of overcorrection (1.5%) but a wider spread in astigmatism (mean 0.63 ± 0.35 D and 0.48 ± 0.50 D, respectively). In contrast, the new numeric parameter optimization approach led to postoperative astigmatism values (mean 0.40 ± 0.08 D, 0.20 ± 0.08 D, and 0.04 ± 0.13 D) that closely matched the target astigmatism (0.40 D, 0.20 D, and 0.00 D), respectively, while keeping the number of overcorrections low (<1.5%). CONCLUSION: Using numeric modeling to optimize surgical parameters for arcuate keratotomy led to more reliable postoperative astigmatism, limiting the risk for overcorrection.

Vector Analysis of Femtosecond Laser-Assisted Arcuate Keratotomy for Post-Keratoplasty Astigmatic Correction.

PURPOSE: To study the astigmatic correction of high post-keratoplasty astigmatism using Femtosecond laser (FSL)-assisted Arcuate Keratotomy (FS-AK). METHODS: A prospective interventional cohort study. We enrolled 17 eyes with high degree of irregular astigmatism, scheduled for FS-AK. FSL was used to perform paired arcuate incisions 1.00 mm inside the graft. Patients' uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), and astigmatic change were recorded and followed up to 1 year after surgery. Vector analysis using Alpins' method was done to analyze the astigmatic correction. RESULTS: FS-AK reduced the refractive astigmatism at final follow-up visit at 12 months (p = 0.0008, repeated-measures analysis of variance [ANOVA]). The procedure improved the UCVA over the follow-up period (p = 0.007, repeated-measures ANOVA), with a similar effect on the BCVA (p = 0.046, repeated-measures ANOVA). There was a mild correlation between the target-induced astigmatism and the surgically induced astigmatism (R2 = 0.245) with a tendency to overcorrect more than under correct the astigmatism. A constant rotational error in the counterclockwise direction was also detected. CONCLUSIONS: FS-AK improves the visual outcome and reduces the refractive cylinder in post-penetrating keratoplasty astigmatism. The predictability of astigmatism correction was variable in reducing post-keratoplasty astigmatism. Refinement of the treatment nomogram for such cases is highly recommended.

Lensectomy after radial keratotomy: 1-year follow-up.

PURPOSE: To report visual and refractive results in radial keratotomy (RK) patients that underwent a cataract surgery with a monofocal intraocular lens (IOL) implantation with 1 year of follow-up. METHODS: Twenty-eight eyes of 15 patients with cataract and the previous RK were included. All eyes underwent phacoemulsification and monofocal IOL implantation. IOL power calculation was done using the Double-K formula of Aramberri. The preoperative versus postoperative corrected distance visual acuity (CDVA) and the uncorrected distance visual acuity (UDVA) values were used to assess the efficacy and safety of the surgery; meanwhile, the achieved versus the expected refractive outcomes postoperatively were used to assess the predictability. RESULTS: Phacoemulsification and IOL implantation was performed successfully in all eyes, and no intra- and postoperative problems occurred. The mean logMAR UDVA significantly improved from 0.7 ± 0.3 to 0.4 ± 0.2 at 6 months, and 0.3 ± 0.2 at 12 months postoperatively. By the end of the follow-up period, about 60% of the eyes achieved 20/25 or better CDVA, 25% of the eyes gained three or more lines of visual acuity, and two eyes had lost one or more lines of visual acuity. The mean spherical equivalent improved from - 1 ± 6.00 to - 0.75 ± 1.1 D by the end of the follow-up, and about 60% of the eyes were within ± 1 D at 12 months after the surgery. No intra- and postoperative problems occurred. CONCLUSIONS: Pseudophakic monofocal IOL implantation offers good visual acuity recovery and acceptable refractive correction in RK patients after 1-year follow-up.

Deep Intrastromal Arcuate Keratotomy With In Situ Keratomileusis (DIAKIK) for the Treatment of High Astigmatism After Keratoplasty: 2-Year Follow-up.

PURPOSE: To describe 2-year results of deep intrastromal arcuate keratotomy with in situ keratomileusis (DIAKIK) for the treatment of high astigmatism after keratoplasty. METHODS: This prospective study included 20 eyes from 20 patients presenting with high astigmatism after keratoplasty. All were treated by two-step femtosecond laser surgery, with two intrastromal arcuate keratotomies and a corneal flap, followed a few months later by excimer photoablation after reopening of the flap. RESULTS: At 24 months, both uncorrected (UDVA) and corrected (CDVA) distance visual acuity had improved from 1.12 ± 0.42 logMAR (20/200 Snellen) before surgery to 0.58 ± 0.23 logMAR (20/80 Snellen) (P < .001) and from 0.31 ± 0.26 logMAR (20/40 Snellen) to 0.20 ± 0.20 logMAR (20/32 Snellen) (P = .04), respectively. The mean spherical equivalent improved from -5.01 ± 4.35 to -1.54 ± 2.42 diopters. The mean efficacy index was 0.63. The mean correction index was 0.93 ± 0.32. The mean flattening index was 1.09 ± 0.75 and the mean safety index was 1.39. No graft rejection or epithelial ingrowth was observed. CONCLUSIONS: This two-step procedure was an effective treatment for high astigmatism after keratoplasty. The use of both femtosecond and excimer lasers helped to avoid some complications that would have jeopardized the grafts. Refractive and topographic stability was good 2 years after surgery. [J Refract Surg. 2019;35(4):239-246.].

Long-term Results of Mini Asymmetric Radial Keratotomy and Corneal Cross-linking for the Treatment of Keratoconus.

PURPOSE: To investigate the long-term results (at least 5 years of follow-up) of the mini asymmetric radial keratotomy (MARK) and corneal cross-linking (CXL) combined intervention, also known as the 'Rome protocol,' for patients with progressive stage I and II keratoconus and contact lens intolerance. METHODS: This was a retrospective observational case series. Fifteen eyes of 12 patients were evaluated, with a mean follow-up of 6.9 years. To assess the efficacy and stability of the MARK + CXL combined protocol, best spectacle-corrected visual acuity, mean pachymetry, and mean keratometry were recorded preoperatively and at least 1, 3, and 5 years postoperatively. Statistical analysis was performed using the R platform and involved the Wilcoxon signed-rank and Kruskal-Wallis non-parametric tests. RESULTS: Best spectacle-corrected visual acuity improved for all patients, from 0.46 ± 0.69 logarithm of the minimum angle of resolution (20 / 60) to 0.15 ± 0.69 logarithm of the minimum angle of resolution (20 / 30, p = 0.0006), while mean pachymetry increased in 93% of patients, from 442.80 ± 61.02 to 464.50 ± 62.72 µm (p = 0.003). Lastly, mean keratometry improved in 87% of patients after 6.9 years of observation from 48.82 ± 5.00 to 43.25 ± 3.58 diopters (p = 0.008). No intraoperative or postoperative complications were observed. CONCLUSIONS: The MARK + CXL combined protocol was effective in treating keratoconus by halting corneal thinning and bulging. In addition, this procedure significantly improved visual acuity based on long-term follow-up data. Analysis of data from a larger cohort of patients would be useful to support these findings.

Refractive correction with multifocal intraocular lenses after radial keratotomy.

PURPOSE: To assess visual and refractive results of multifocal intraocular lens (IOLs) implantation for refractive correction after radial keratotomy (RK). METHODS: In a retrospective non-comparative interventional case series, we analyzed the outcomes of multifocal IOL implantation performed in the context of cataract or refractive lens exchange surgery following RK. A total of 17 eyes from nine patients were included in the study. IOL power calculation was done using the Double-K formula. Refractive error was used to assess predictability, and distance-corrected visual acuity (DCVA) and uncorrected distance visual acuity (UDVA) values were used to assess the surgical procedure's efficacy and safety. Distance-corrected near visual acuity (DCNVA) was also determined. RESULTS: Phacoemulsification and multifocal IOL implantation was successful in all cases, with neither complications nor adverse events. At 6 months postoperatively, monocular UDVA, DCVA, and DCNVA were 0.51 ± 0.39, 0.20 ± 0.30, and 0.11 ± 0.11, respectively (logMAR scale). More specifically, 35.29% of the eyes had DCVA ≥20/20 and 52.94% showed DCVA ≥20/25. Regarding pre- vs. post-operative changes, 52.94% had lost one line of DCVA, 23.53% showed no changes, 11.76% had gained one line of DCVA, 5.88% had gained two lines, and 5.88% had gained three or more lines. The efficacy and safety indexes were 0.56 and 0.98, respectively. As for near vision surgical outcomes, 29.41% of the eyes had DCNVA ≥20/20 and 64.71% had DCNVA ≥20/25. As for surgical accuracy, 29% of the eyes were within ±0.50 D of the target refraction, whereas 65% were within ±1.00 D. CONCLUSIONS: Multifocal IOL implantation following radial keratotomy (RK) does not result in good distance visual performance, at least after 6 months of follow-up. Thus, this surgical approach has to be considered with only limited expectations.

Evaluation of Big Bubble Technique for Deep Anterior Lamellar Keratoplasty in Patients With Radial Keratotomy.

PURPOSE: To report the outcome of deep anterior lamellar keratoplasty (DALK) and success rates of the big-bubble (BB) technique or manual dissection after a failed use of the BB technique in eyes that underwent prior radial keratotomy (RK). METHODS: A retrospective chart review of patients who underwent DALK after RK at Toronto Western Hospital, Canada, between 1999 and 2017 was performed. Demographic characteristics, success rates of the BB technique and manual dissection, intraoperative and postoperative complications, and best spectacle-corrected visual acuity before and after corneal transplant were analyzed. RESULTS: Ten eyes of 9 patients were included in the analysis. The average age was 64 ± 10 years (range 49-82). The average time between the RK surgery and the corneal transplant was 20 ± 5 years (range 8-24). Indications for corneal transplant were significant irregular astigmatism in 5 eyes (50%), central scarring or haze in 4 eyes (40%), and progressive hyperopia with visual fluctuation in one eye (10%). BB was successfully achieved in one eye (10%). In 6 eyes (60%), manual dissection was performed, and in 3 eyes (30%), DALK surgery was converted to penetrating keratoplasty. The average best spectacle-corrected visual acuity on the last follow-up visit was 0.26 ± 0.08 logMAR (Snellen equivalent 20/36). One eye that underwent manual DALK and one eye that underwent penetrating keratoplasty developed a rejection episode 4 and 2 months after keratoplasty, respectively. In both cases, rejection resolved with topical steroids. CONCLUSIONS: In eyes that underwent prior RK, DALK by manual dissection should be considered as a preferable surgical technique.