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.

Refractive Outcomes With New Generation Formulas for Intraocular Lens Power Calculation in Radial Keratotomy Patients.

PURPOSE: Radial keratotomies (RKs) are responsible for corneal irregularities resulting in biometric errors and lower best-corrected visual acuity (BCVA) due to lower-order and higher-order optical aberrations. The aim of the study was to compare performances of new and old generation formulas in a population of RK patients. METHODS: RK patients who underwent phacoemulsification with intraocular lens (IOL) implantation were retrospectively recruited. Inclusion criteria were availability of preoperative and 6-month postoperative BCVA assessment, topography, and tomography. Documented refraction instability, corneal ectasia, and previous ocular surgery except for RK were exclusion criteria. Mean prediction error (ME), mean absolute prediction error (MAE), and incidence of MAE > 0.25D were calculated for SRK-T, Barrett True K, EVO 2.0, Kane, and PEARL-DGS. RESULTS: Twenty-seven patients with a mean baseline BCVA of 0.32 ± 0.18 logMAR and a mean corneal root mean square (RMS) value of 1.59 ± 0.91 µm were included. EVO 2.0, Kane, and PEARL-DGS showed a significantly lower MAE and lower ME compared with all other formulas ( P < 0.001 and P < 0.001) and a significant lower incidence of MAE >0.25D ( P < 0.001). Significant differences were still detected when using 3-mm mean keratometry for IOL calculation. CONCLUSIONS: PEARL-DGS, Kane, and EVO 2.0 formulas show superior accuracy in IOL power calculation compared with SRK-T and Barrett True K in RK patients, with no significant differences between the 3.

Sequential Customized Therapeutic Keratectomy in Patients With a History of Radial Keratotomy.

PURPOSE: To evaluate the outcome of sequential customized therapeutic keratectomy (SCTK) in reducing higher order aberrations (HOAs) and improving quality of vision in highly aberrated corneas consequent to previous radial keratotomy (RK). METHODS: A retrospective review of patients undergoing SCTK treatment from January 2012 to October 2020 was conducted in the Eye Center, Humanitas Clinical and Research Center (Rozzano, Italy). Indications for treatment in patients who had RK were significantly and/or progressively reduced corrected distance visual acuity (CDVA) combined with visual symptoms critically affecting quality of life. Preoperative and postoperative CDVA, corneal topography and aberrometry, Scheimpflug tomography, and anterior segment optical coherence tomography were registered. RESULTS: Thirty-four patients who underwent RK a mean of 26.62 ± 7.10 years before SCTK treatment were included. SCTK induced a significant improvement of CDVA from 0.44 ± 0.82 logMAR preoperatively to 0.15 ± 0.64 logMAR postoperatively (P < .001). No patient experienced worsening of CDVA, whereas 8 patients (23,50%) gained one line and 23 patients (67.65%) gained two lines or more. A significant decrease in corneal coma, trefoil, and spherical aberrations was also noted (P = .003, .003, and .004, respectively). CONCLUSIONS: SCTK proved to be a safe and effective option to treat highly aberrated eyes following RK. The authors suggest the use of SCTK as a first-line approach for the treatment of HOAs after RK and avoiding more invasive procedures such as corneal transplantation or intraocular lens implantation. [J Refract Surg. 2023;39(12):808-816.].

Comparison of intraocular lens power prediction accuracy of formulas in American Society of Cataract and Refractive Surgery post-refractive surgery calculator in eyes with prior radial keratotomy.

Purpose: To evaluate the accuracy of intraocular lens (IOL) power prediction of the formulas available on the American Society of Cataract and Refractive Surgery (ASCRS) post-refractive calculator in eyes with prior radial keratotomy (RK) for myopia. Methods: This retrospective study included 25 eyes of 18 patients whose status was post-RK for treatment of myopia, which had undergone cataract extraction with IOL implantation. Prediction error was calculated as the difference between implanted IOL power and predicted power by various formulae available on ASCRS post-refractive calculator. The formulas compared were Humphrey Atlas method, IOLMaster/Lenstar method, Barrett True-K no-history formula, ASCRS Average power, and ASCRS Maximum power on ASCRS post-refractive calculator. Results: Median absolute errors were the least for Barrett True-K and ASCRS Maximum power, that is, 0.56 (0.25, 1.04) and 0.56 (0.25, 1.06) D, respectively, and that of Atlas method was 1.60 (0.85, 2.28) D. Median arithmetic errors were positive for Atlas, Barrett True-K, ASCRS Average (0.86 [-0.17, 1.61], 0.14 [-0.22 to 0.54], and 0.23 [-0.054, 0.76] D, respectively) and negative for IOLMaster/Lenstar method and ASCRS Maximum power (-0.02 [-0.46 to 0.38] and - 0.48 [-1.06 to - 0.22] D, respectively). Multiple comparison analysis of Friedman's test revealed that Atlas formula was significantly different from IOLMaster/Lenstar, Barrett True-K, and ASCRS Maximum power; ASCRS Maximum power was significantly different from all others (P < 0.00001). Conclusion: In post-RK eyes, Barrett True-K no-history formula and ASCRS Maximum power given by the ASCRS calculator were more accurate than other available formulas, with ASCRS Maximum leading to more myopic outcomes when compared to others.

Radial keratotomy and cataract surgery: A quest for emmetropia.

A 75-year-old man with an ocular history of 8-cut radial keratotomy (RK) in both eyes presented for cataract surgery evaluation. He was previously correctable in spectacles in years prior despite his irregular corneas to 20/25 in the right eye and 20/30 in the left eye. He recently noticed a change in his overall visual function with significant nighttime glare and difficulty reading despite spectacle correction. Of note, he was unable to tolerate contact lenses and was resistant to refitting despite additional encouragement. Cataract surgery was delayed for many years, given he was correctable in spectacles and the concern of uncovering a highly aberrated cornea after removing his cataracts (Figures 1 and 2JOURNAL/jcrs/04.03/02158034-202308000-00021/figure1/v/2023-07-21T030437Z/r/image-tiffJOURNAL/jcrs/04.03/02158034-202308000-00021/figure2/v/2023-07-21T030437Z/r/image-tiff). Of note, the patient was interested in returning to the spectacle independence he enjoyed in the past. Ocular examination revealed a corrected distance visual acuity (CDVA) of 20/30 in the right eye and 20/60 in the left eye, with a manifest refraction of +4.50 -0.50 × 177 in the right eye and +5.75 -1.75 × 14 in the left eye. Glare testing was 20/50 in the right eye and 20/100 in the left eye, with retinal acuity meter testing of 20/25 in each eye. Pupils, confrontation visual fields, and intraocular pressures were normal. Pertinent slitlamp examination revealed corneal findings of 8-cut RK with nasal-gaping arcuate incisions in both eyes and lens findings of 2+ nuclear sclerosis with 2+ cortical changes in the right eye and 3+ nuclear sclerosis with 3+ cortical changes in the left eye. Cup-to-disc ratios of the optic nerves measured 0.5 with temporal sloping in the right eye and 0.6 with temporal sloping in the left eye. The dilated fundus examination was unremarkable. What intraocular lens (IOL) options would you offer this patient and how would you counsel regarding realistic expectations? What additional diagnostic testing would be helpful in your assessment? How would you calculate the IOLs?

Rare case of corneal keloid following radial keratotomy for myopia.

An adult male in his 50s presented with complaints of glare and gradual, painless, progressive diminution of vision in the right eye (RE). Visual acuity in RE was noted to be 2/60, and slit lamp biomicroscopy revealed a pearly grey-white elevated corneal opacity measuring 4 mm × 3 mm, obscuring the visual axis. There was no history of ocular trauma or infection. The patient had undergone bilateral radial keratotomy for myopia correction 25 years ago. Anterior segment optical coherence tomography imaging demonstrated increased corneal thickness of 1080 µm at the site of lesion and the height of the epicorneal mass was noted to be 493 µm. The patient underwent fibrin glue-aided anterior lamellar keratoplasty. Histopathological examination of the excised host tissue confirmed the diagnosis of corneal keloid.

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.

Therapeutic visual rehabilitation in a patient with high hyperopia and flat cornea years after radial keratotomy.

A 51-year-old man was referred for refractive surgery evaluation. Spectacle dependence and poor visual quality in both eyes was his chief complaint. He cannot tolerate contact lenses. Corrected distance visual acuity (CDVA) was 20/40 in both eyes. Manifest refraction was +5.25 -2.25 @ 90 (20/40) in the right eye and +6.25 -2.25 @ 105 (20/40) in the left eye. The patient had a history of radial keratotomy (RK) almost 30 years ago in both eyes and at the slitlamp presented 8 RK incisions, proportionally spaced between one another. All incisions were closed, and there were no relevant signs of scarring. The patient denied any history of ocular trauma, systemic disease, or medications. Corneal topography with different technologies revealed an irregular pattern with marked central flattening in both eyes, with some points below 30 diopters (D) (Supplemental Figures 1 and 2, available at http://links.lww.com/JRS/A862 and http://links.lww.com/JRS/A863, respectively). There were no signs of cataract, and fundus examination was normal. Optical coherence tomography (OCT) of the right eye revealed a more homogeneous thickness pattern, little variation between the thinnest and thickest areas, and adequate transparency (Figure 1JOURNAL/jcrs/04.03/02158034-202306000-00018/figure1/v/2023-05-31T172126Z/r/image-tiff). In the left eye, there is wide variability between the thinnest and thickest stromal points, with annular thinning and central thickening (Figure 2JOURNAL/jcrs/04.03/02158034-202306000-00018/figure2/v/2023-05-31T172126Z/r/image-tiff). Both eyes show marked epithelial irregularity. Considering this patient's current ocular status, how would you reach visual rehabilitation? Because he is contact lens intolerant, would you consider surface ablation, for example, photorefractive keratectomy (PRK) with mitomycin-C (MMC)? If that were the case, would you think of an optimized or a topography-guided (TG) treatment? Would you immediately consider a corneal transplant option? Would you instead consider a more conservative approach? Which one and why?

Femtosecond Laser Capsulotomy in Previous Radial Keratotomy.

PURPOSE: The aim of this study was to describe clinical experience using femtosecond laser-assisted anterior capsulotomy in eyes with previous radial keratotomy. METHODS: Eyes of patients with previous radial keratotomy and cataract-related vision impairment who underwent phacoemulsification and intraocular lens implantation were retrospectively reviewed. Eyes with any vision impairment cause other than cataract or previous radial keratotomy were excluded. RESULTS: Sixteen postradial keratotomy eyes were included. In 5 patients, manual anterior capsulectomy was successfully performed. Six eyes underwent femtosecond laser capsulotomy using routine parameters (incision depth 500 µm and 4 µJ power), of which in 3 eyes capsulotomies were complete, whereas in the other 3 eyes incomplete capsulotomy was evident. In 3 patients, both incision depth and power parameters were doubled (incision depth 1000 µm and 8 µJ power), whereas in 2 patients, only the pulse energy was doubled (8 µJ power) and in all 6 cases, the capsulotomy was successfully completed. At the last follow-up, all capsulotomies were intact without radial tears, and the intraocular lenses were stable and central. CONCLUSIONS: Radial corneal scars after previous radial keratotomy may interfere with femtosecond laser-assisted anterior capsulotomy using routine parameters. Surgeons should be alert and ready to convert to manual anterior capsulectomy. Modification of the laser parameters may overcome this potential complication.

Comparison of the accuracy of three intraocular lens power calculation formulas in cataract patients with prior radial keratotomy.

PURPOSE: To compare the accuracy of three intraocular lens (IOL) formulas in Chinese cataract patients with prior radial keratotomy (RK). METHODS: Medical records of cataract patients with prior RK at Beijing Tongren Hospital were retrospectively analysed. The absolute error (AE) was calculated as the absolute difference between the actual postoperative spherical equivalent and the predicted spherical equivalent. The AE and percentages of eyes with AE within 0.5D, 1.0D, and 2.0D for three formulas [Barrett True-K, Holladay 1 (D-K), Haigis] were calculated and compared. RESULTS: Forty-seven eyes of 28 cataract patients were included. The Median AE (MedAE) was significantly different among the three formulas (P < 0.001). The MedAE was lowest for the Barrett True-K formula (0.62), followed by the Haigis (0.76), and Holladay 1 (D-K) (1.16). The percentages of eyes with AE within 0.5D, and 1.0D were significantly different among the 3 formulas (P = 0.009, and P < 0.001). The Barrett True-K formula achieved the highest percentages (46.8%) of eyes with AE within 0.5D. Haigis achieved the highest percentages (70.21%) of eyes with AE within 1.0 D. CONCLUSIONS: Barrett True-K is the most accurate IOL power calculation formula among the 3 formulas and Haigis is an alternative choice. Considering the relatively lower accuracy of IOL formulas in cataract patients with prior RK, newer and more accurate IOL formulas are desirable.

Large-Diameter Modified Big-Bubble Deep Anterior Lamellar Keratoplasty in Post-Radial Keratotomy Eyes.

PURPOSE: To report the outcomes of our modified large-diameter (9-mm) big-bubble deep anterior lamellar keratoplasty (DALK) technique with improved success rates of pneumatic dissection in post-radial keratotomy (RK) eyes. DESIGN: Retrospective case series. METHODS: At Ospedali Privati Forlì, "Villa Igea," Forlì, Italy., modified big-bubble DALK was performed in consecutive post-RK eyes. The technique included large-diameter (9-mm) deep partial-thickness trephination based on the thinnest anterior segment optical coherence tomography pachymetry value at 9 mm, air injection through a cannula advanced 2 mm centripetally from the base of the trephination, limited stromal clearance of the central 6-mm optical zone, and suturing of a 9-mm anterior lamellar graft prepared by microkeratome dissection. Success rate of pneumatic dissection, corrected distance visual acuity (CDVA), keratometric astigmatism, and complications were recorded. RESULTS: Eight eyes of 7 patients were included. Pneumatic dissection succeeded in 7 cases (87.5%). CDVA significantly improved from 0.94 ± 0.43 to 0.14 ± 0.06 logMAR (P < .001). All eyes reached Snellen CDVA ≥20/40, whereas 3 eyes (37.5%) reached ≥20/25. At the last follow-up, 5 eyes (62.5%) had a final keratometric astigmatism ≤4 diopters, whereas 2 eyes (25.0%) had ≤2 diopters. CONCLUSION: Big-bubble DALK can be successfully performed in post-RK eyes with our standardized technique.

Ray tracing biometry in post radial keratotomy eye.

OBJECTIVE: To report a case of post radial keratotomy (RK) cataract in a 55-year-old lady wherein biometry was done by ray-tracing method incorporated in scheimpflug topographer (Sirius + Scheimpflug Analyzer, CSO, Italy). METHOD: In our case, we performed intraocular lens (IOL) power calculation using a recent concept of ray tracing with scheimpflug topographer and compared with traditional methods available at American Society of Cataract and Refractive Surgery(ASCRS) website (www.ascrs.org) for eyes with prior RK. Phacoemulsification was performed and a monofocal + 24.5D IOL implanted in the capsular bag. RESULT: Manifest refraction at six weeks postoperative period was + 1.0DS/-2.0DC × 75° with spherical equivalence of 0. On comparison of all the methods used to calculate IOL power, the absolute errors of ray tracing and Barrett true K were found to be the least, 0.14 and 0.18 respectively. CONCLUSION: Ray tracing biometry with scheimpflug topographer seems to provide accurate IOL power in post RK eyes.

Late Spontaneous Postradial Keratotomy Corneal Perforation After Scleral Contact Lens Use-Case Report.

PURPOSE: To describe a case of late spontaneous postradial keratotomy corneal perforation after scleral contact lens (SCL) wear for optic correction. SETTING: Tertiary referral center for corneal pathology. DESIGN: Case report. RESULTS: A 64-year-old man presented the consequences of a late radial keratotomy (RK) surgery performed for myopia correction 26 years ago. His ophthalmologic history was a RK in both eyes (BE), previous Lasik surgery in BE and Lasik enhancement in the right eye (RE), and pterygium excision with conjunctival transplantation in RE. To improve visual acuity, SCL were fitted in both eyes. After 8 months of use, on a certain day, when removing the lens from the RE, the patient reported experiencing intense eye pain and reduced visual acuity. On ophthalmologic examination, the RE cornea was perforated in one of the previous RK incisions. An urgent corneal transplant was performed in the RE, followed by cataract surgery in the same eye. CONCLUSION: Corneal instability caused by RK scars and daily manipulation with the SCL use may have led to ocular perforation.

Cataract Surgery after Radial Keratotomy with Non-Diffractive Extended Depth of Focus Lens Implantation.

Radial keratotomy was a popular surgical procedure used to treat myopia. Patients who underwent radial keratotomy several years ago, are currently reporting to the ophthalmologist due to worsening of vision associated with age-related cataracts. In this case report we present a case of a 60-year-old woman who underwent radial keratotomy with 16 incisions in the right eye and 12 incisions in the left eye. The patient reported to an ophthalmologist due to a deterioration of vision caused by a cataract. We described, in detail, the difficulties encountered during the diagnostic procedures, differences in the calculation of intraocular lens, and intraoperative difficulties as compared to patients who had not undergone radial keratotomy. We also present the obtained postoperative results.

[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.