Comparison of long-term outcomes of simultaneous accelerated corneal crosslinking combined with intracorneal ring segment or topography-guided PRK.

PURPOSE: To compare long-term outcomes of simultaneous accelerated corneal crosslinking (CXL) with intrastromal corneal ring segments (CXL-ICRS) with simultaneous accelerated CXL with topography-guided photorefractive keratectomy (CXL-TG-PRK) in progressive keratoconus (KC). SETTING: Kensington Eye Institute and Bochner Eye Institute, Toronto, Canada. DESIGN: Prospective nonrandomized interventional study. METHODS: The change in visual and topographical outcomes of CXL-ICRS and CXL-TG-PRK 4 to 5 years postoperatively were compared using linear regression models adjusted for preoperative corrected distance visual acuity (CDVA) and maximum keratometry (Kmax). RESULTS: 57 eyes of 43 patients with progressive KC who underwent simultaneous accelerated (9 mW/cm 2 , 10 minutes) CXL-ICRS (n = 32) and CXL-TG-PRK (n = 25) were included. Mean follow-up duration was 51.28 (9.58) and 54.57 (5.81) months for the CXL-ICRS and CXL-TG-PRK groups, respectively. Initial mean Kmax was higher in the CXL-ICRS group compared with the CXL-TG-PRK group (60.68 ± 6.81 diopters [D] vs 57.15 ± 4.19 D, P = .02). At the last follow-up, change (improvement) in logMAR uncorrected distance visual acuity (UDVA) compared with that preoperatively was significant with CXL-ICRS (-0.31 ± 0.27, P < .001, which is equivalent to approximately 3 lines) and not significant with CXL-TG-PRK (-0.06 ± 0.42, P = .43). The logMAR CDVA improved significantly with CXL-ICRS (-0.22 ± 0.20, P < .001), but not with CXL-TG-PRK (-0.05 ± 0.22, P = .25). Adjusting for baseline Kmax and CDVA, the improvement in UDVA was significantly greater with CXL-ICRS than with CXL-TG-PRK (-0.27, 95% CI, 0.06-0.47, P = .01). Improvement in CDVA was not significantly different. CONCLUSIONS: In this cohort of progressive KC with long-term follow-up, UDVA showed more improvement with accelerated CXL-ICRS than with CXL-TG-PRK.

Subjective and objective evaluation of corneal haze after accelerated corneal crosslinking for corneal ectasias.

PURPOSE: To evaluate the relationship between subjective (slit lamp examination [SLE]) and objective (densitometry) measurements of corneal haze after accelerated corneal crosslinking (aCXL), assess the relationship between densitometry and corrected distance visual acuity (CDVA), and determine the effect of baseline characteristics on densitometry after aCXL in eyes with progressive keratoconus and other ectasias. SETTING: Kensington Eye Institute and Bochner Eye Institute, Toronto, Canada. DESIGN: Retrospective analysis of a prospective interventional cohort study. METHODS: Scheimpflug-derived corneal densitometry, CDVA, maximum keratometry (Kmax ), and central corneal thickness were measured preoperatively and up to 1 year after aCXL, and post-operative haze was estimated with SLE (n = 483 eyes). A random effect model was used to examine the relationship between post-operative subjective haze with SLE and densitometry. Linear mixed models were used to examine the relationship between densitometry, pre-operative baseline characteristics, and CDVA. RESULTS: There was a significant association between subjective haze with SLE and densitometry (p < 0.001). There was a significant relationship between CDVA and densitometry: for every 10 GSUs of increased densitometry in the 0-2 mm zone, CDVA worsened by approximately half a Snellen line (p < 0.001). Age and pre-operative Kmax were significant predictors of densitometry. For every 10 years of age, densitometry increased by 0.68 GSUs (95% CI [0.27 to 1.07], p < 0.001). For every 10 D of increased preoperative Kmax , densitometry increased by 0.69 GSUs (95% CI [0.41 to 0.98], p < 0.001). CONCLUSIONS: Subjective haze after aCXL estimated with SLE, is significantly associated with densitometry. Increased densitometry after aCXL is associated with a reduction in CDVA.

Fellow Eye as a Predictor for Keratoconus Progression Following Accelerated Corneal Cross-linking.

PURPOSE: To assess the fellow eye as a predictor for keratoconus progression following bilateral same-day accelerated corneal cross-linking (A-CXL). METHODS: This was a post-hoc analysis of data from a prospective study of bilateral A-CXL for progressive keratoconus between 2013 and 2015. The primary outcome measures were absolute change in maximum keratometry (Kmax) (diopters [D]), relative change in Kmax (%), and A-CXL progression (increase in Kmax > 2.00 D). Responses in both eyes were measured by the change in Kmax, with the right eye serving as the "predictor" of progression for the left eye. RESULTS: Three-hundred ninety-two eyes (196 patients) with a mean age of 26.8 ± 7.7 years were included. There was a significant correlation in absolute and relative Kmax change (r = 0.26, P < .001 and r = 0.32, P < .001, respectively) between right and left eyes. In regression analysis, the only significant predictors of change in Kmax in the left eye were preoperative Kmax of the left eye (P < .02) and change in Kmax of the right eye (P < .001). Eyes that progressed in the right eye were more likely to progress in the left eye (29.4% versus 4.5%, odds ratio = 8.85, P < .001). In multiple regression, right eye progression of greater than 2.00 D was the significant predictor of left eye progression of greater than 2.00 D (odds ratio = 15.15, P < .007). CONCLUSIONS: This large-scale study of keratoconus following A-CXL indicates that patients with progression in the right eye were 15.5 times more likely to have progression in the left eye. Patients with progression following A-CXL in one eye should be closely observed due to increased risk of progression in the fellow eye. [J Refract Surg. 2021;37(3):186-191.].

Central versus paracentral cone location and outcomes of accelerated cross-linking in keratoconus patients.

PURPOSE: To compare outcomes 1 year after accelerated cross-linking (CXL) between keratoconus eyes with central cones to those with paracentral cones. METHODS: In this post hoc analysis of data from a prospective multicentre study, consecutive progressive keratoconus eyes treated with accelerated CXL were included. Preoperative and 1 year post CXL manifest refraction, corneal cylinder, maximal keratometry (Kmax), central corneal thickness and coma were assessed. Central and paracentral cones were defined as cones within the central 3 mm and those between 3 and 5 mm, respectively. Eyes with apical scarring and peripheral cones (>5 mm) were excluded. The primary outcome measures were changes in best spectacle-corrected visual acuity (BSCVA) and Kmax. RESULTS: Overall, 314 eyes (n = 314) with a mean age of 27.5 ± 7.7 years were included. At baseline, the central cone group was younger (p < 0.001), had lower corneal astigmatism (p = 0.03) and coma (p = 0.02). At 1 year post CXL, after adjusting for baseline characteristics (age, BSCVA, corneal astigmatism, Kmax and coma), the central cone group showed a greater reduction in myopia (mean difference 1.27 ± 0.60D, p = 0.04) and more improvement in BSCVA (mean difference 0.08 ± 0.02 logMAR, p < 0.001) compared to the paracentral group. There was no significant difference in progression rates between the central and paracentral groups (ΔKmax > 2D, 6.7% vs. 6.5%, respectively, p = 0.83). CONCLUSIONS: This large-scale study of keratoconus eyes 1 year after accelerated CXL indicates that compared to those with paracentral cones, central cones have on average almost one additional line improvement in BCSVA and 1.27 D more reduction in myopia.

Comparison of accelerated CXL alone, accelerated CXL-ICRS, and accelerated CXL-TG-PRK in progressive keratoconus and other corneal ectasias.

PURPOSE: To compare accelerated corneal crosslinking (CXL) alone, CXL with simultaneous intrastromal corneal ring segments (CXL-ICRS), and CXL with simultaneous topography-guided photorefractive keratectomy (CXL-TG-PRK) in progressive keratoconus, pellucid marginal degeneration (PMD), or laser in situ keratomileusis (LASIK)-induced ectasia. SETTING: The Kensington Eye Institute and Bochner Eye Institute, Toronto, Canada. DESIGN: Prospective nonrandomized interventional study. METHODS: Visual and topographical outcomes using a comparative analysis adjusting for preoperative maximum keratometry (Kmax) were evaluated 1 year postoperatively. RESULTS: Four hundred fifty-two eyes from 375 patients with progressive keratoconus, PMD, or LASIK-induced ectasia that underwent accelerated (9 mW/cm, 10 minutes) CXL alone (n = 204), CXL-ICRS (n = 126), or CXL-TG-PRK (n = 122) were included. Change in logarithm of the minimum angle of resolution uncorrected distance visual acuity was significant with CXL-ICRS (-0.31; 95% CI, -0.38 to -0.24) and CXL-TG-PRK (-0.16; 95% CI, -0.24 to -0.09), but not with CXL alone. No significant differences in change were found between the 3 groups. Change in corrected distance visual acuity (CDVA) was significant in all 3 groups: -0.12 (95% CI, -0.15 to -0.10) with CXL alone, -0.23 (95% CI, -0.27 to -0.20) with CXL-ICRS, and -0.17 (95% CI, -0.21 to -0.13) with CXL-TG-PRK. Improvement in CDVA was greater with CXL-ICRS than with CXL alone (-0.08 ± 0.02; P < .0001) and CXL-TG-PRK (-0.05 ± 0.02; P = .005). Change in Kmax was significant with CXL-ICRS [-3.21 diopters (D); 95% CI, -3.98 to -2.45] and CXL-TG-PRK (-3.69 D; 95% CI, -4.49 to -2.90), but not with CXL alone (-0.05 D; 95% CI, -0.66 to 0.55). CONCLUSIONS: CXL alone might be best for keratoconic patients who meet the inclusion criteria. CXL-ICRS might be more effective for eyes with more irregular astigmatism and worse CDVA and CXL-TG-PRK for eyes requiring improvements in irregular astigmatism but still have good CDVA.

Accelerated Corneal Cross-Linking: Efficacy, Risk of Progression, and Characteristics Affecting Outcomes. A Large, Single-Center Prospective Study.

PURPOSE: We examined the efficacy and preoperative characteristics that affect outcomes of accelerated (9 mW/cm2 for 10 minutes) corneal cross-linking (CXL). DESIGN: Prospective single-center observational cohort study. METHODS: We enrolled 612 eyes of 391 subjects with progressive keratoconus (n = 589), pellucid marginal degeneration (n = 11), and laser in situ keratomileusis-induced ectasia (n = 12). We evaluated best spectacle-corrected visual acuity (BSCVA), topography, refraction, endothelial cell density, corneal thickness, haze, intraocular pressure, and visual function before and 12 months after the CXL procedure. We tabulated the proportion of those with progression of maximum keratometry (Kmax). We included participant's race, age, sex, and the presence of preoperative apical scarring and environmental allergies in a multivariable linear regression model to determine the effect of these characteristics on outcomes. RESULTS: At 1 year there was no significant change in mean Kmax (n = 569). Progression of Kmax was higher in subgroups with a baseline Kmax >58 diopters (n = 191) and those 14-18 years of age (n = 53). Preoperative BSCVA, Kmax, refraction, corneal cylinder, coma, central corneal thickness, and vision function were statistically and clinically significant predictors of outcomes (P < .001). Preoperative apical scarring led to worsening haze (P = .0001), more astigmatism (P = .002), more central corneal thinning (P = .002), and was protective to the endothelium (P = .008). Race, age, and sex affected some outcomes. CONCLUSION: Mean Kmax was stable at 1 year after accelerated CXL. Younger patients and those with a higher preoperative Kmax need to be monitored closely for progression. Preoperative BSCVA, topography, refraction, CCT, and apical scarring were significant predictors of outcomes.

Zig Zag versus Top Hat configuration in IntraLase-enabled penetrating keratoplasty.

AIM: To compare the outcomes with IntraLase-enabled keratoplasty using (IEK) Top Hat (TH) versus Zig Zag (ZZ) configuration. METHODS: Retrospective comparative series of 24 eyes that underwent TH and 10 eyes that underwent ZZ IEK. RESULTS: There were no significant differences in LogMar Best-spectacle corrected visual acuity (TH- IEK=0.3; ZZ-IEK=0.18, p=0.18), spherical equivalent (TH-IEK=-3.55±3.7 dioptres (D); ZZ-IEK=-2.69±4.85 D, p=0.60), manifest cylinder (TH- IEK=3.79±2.43 D; ZZ- IEK=4.61±3.29 D, p=0.45), topographic astigmatism (TH-IEK=3.67±2.34 D; ZZ-IEK=4.26±1.1 D, p=0.63), total higher-order aberrations (TH- IEK=8.26±3.53; ZZ-IEK=8.1±4.71, P=0.92), endothelial cell density change from baseline (TH- IEK= -41.55%±15.86; ZZ-IEK=-25.45%±30.66, p=0.22) or time to suture removal in months (TH- IEK=7.48±4.07; ZZ- IEK=6.93±2.71, p=0.75). There was no difference in requirements for astigmatic keratectomy (TH-IEK=54.2%±13; ZZ-IEK=50%±5, OR=1.18) or complications (TH-IEK=25%±6; ZZ-IEK=30%±3, OR=0.78). CONCLUSIONS: TH-IEK and ZZ-IEK have comparable visual and refractive outcomes, wound healing and endothelial cell counts at 1-year.

Intrastromal corneal ring segment SK implantation for moderate to severe keratoconus.

PURPOSE: To report the efficacy and safety of intrastromal corneal ring segment (ICRS) implantation using a femtosecond laser in the management of advanced keratoconus. SETTING: Private laser center, Toronto, Ontario, Canada. METHOD: In this retrospective nonrandomized study, Intacs SK ICRS were implanted using an IntraLase femtosecond laser in eyes with moderate to severe keratoconus. Evaluation included uncorrected (UDVA) and corrected (CDVA) distance visual acuity, manifest refraction, slitlamp examination, corneal topography, and wavefront analysis of higher-order aberrations. Postoperative visits were at 1, 7, and 30 days and 3 and 6 months. RESULTS: The study evaluated 10 eyes of 8 patients with a mean age of 28 years (range 21 to 42 years). The mean UDVA was significantly better 6 months postoperatively than preoperatively (0.66 logMAR +/- 0.21 [SD] versus 1.19 +/- 0.57 logMAR) (P = .004), as was the mean CDVA (0.25 +/- 0.15 logMAR versus 0.51 +/- 0.20 logMAR) (P = .018). The mean spherical equivalent refractive error was -8.08 diopters (D) preoperatively and -5.03 D at 6 months (P = .65); the mean refractive astigmatism, -5.05 D and -3.90 D, respectively (P = .22); and the mean simulated keratometry value, 57.94 D and 50.07 D, respectively (P = .15). The mean total aberration improved significantly, from 13.48 +/- 4.64 mum preoperatively to 9.42 +/- 1.80 mum postoperatively (P = .007). There were no complications. CONCLUSION: Implantation of ICRS for advanced keratoconus was safe and effective, leading to significant improvement in UDVA, CDVA, and total aberrations. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Pseudophakic cystoid macular edema: ketorolac alone vs. ketorolac plus prednisolone.

BACKGROUND: Pseudophakic cystoid macular edema (CME) following phacoemulsification is the most common complication after cataract surgery. Treatment focuses on the reduction of inflammation with topical use of both steroids and NSAIDS. The latter have been shown to be of benefit in chronic CME, but topical NSAID and steroid treatment has only recently been shown to be of benefit in acute CME. We evaluated the use of topically administered NSAIDS and steroids in the management of both acute and chronic pseudophakic CME. METHODS: This was a prospective double-masked randomized controlled trial. Patients with clinical CME occurring at least 6 weeks following cataract extraction were referred for consideration of enrolment. Patients were excluded if they had Snellen vision better than 20/40, no CME on clinical examination, no CME on angiography, recent use of steroids, preexisting macular disease or diabetic maculopathy on angiography. Ten patients were randomly assigned to receive either 0.5% ketorolac tromethamine plus placebo (four patients) or 0.5% ketorolac tromethamine plus 1% prednisolone acetate (six patients); all 10 completed the study. Patients were assessed at baseline and at 30, 60 and 90 days. Fluorescein angiography was performed at baseline and at 90 days. The primary outcome measures were improvement in Early Treatment Diabetic Retinopathy Study Snellen equivalent vision and resolution of cysts on clinical examination. RESULTS: No statistically significant differences were found between the two groups in either of the outcome measures at any visit. Subgroup analysis of the patients with chronic CME also showed no significant difference between the two groups. INTERPRETATION: We found no statistically significant difference in outcome between patients who received ketorolac and those who received ketorolac plus prednisolone for acute or chronic CME. The value of topical steroid therapy for chronic CME remains unproven.

Piggyback intraocular lens implantation to correct myopic pseudophakic refractive error after penetrating keratoplasty.

PURPOSE: To determine the safety and efficacy of implanting a second intraocular lens (IOL) to correct myopic pseudophakic refractive error after penetrating keratoplasty (PKP). SETTING: Department of Ophthalmology, Toronto Western Hospital, Toronto, Ontario, Canada. METHODS: In this retrospective case series, 6 eyes of 6 post-PKP pseudophakic patients had a second piggyback IOL implantation to correct a residual myopic refractive error. The uncorrected visual acuity (UCVA) and the best corrected visual acuity (BCVA) were measured at regular intervals during a 7-month follow-up. Efficacy was determined by the achieved refractive correction and Snellen UCVA measurements. Safety was measured by loss of BCVA and complications (intraoperative and postoperative). RESULTS: The UCVA improved in all cases. Five patients achieved a BCVA of 20/40 or better postoperatively. Before surgery, the mean spherical equivalent (SE) was -8.08 diopters (D) (range -6.13 to -12.00 D). After surgery, the mean SE was -0.94 D (range -2.38 to +0.25 D). Four patients were within +/-1.50 D of emmetropia. There were no intraoperative or postoperative complications. CONCLUSION: Implanting a piggyback IOL was a safe and effective means of correcting myopic pseudophakic refractive error post PKP.