Athens Protocol Research Articles

CXL: Challenges and updates

Corneal cross‐linking (CXL) is a critical treatment for keratoconus that combines UVA light and riboflavin (vitamin B2). This procedure received FDA approval in 2016 based on studies by Sykakis et al. (2015) which indicated that CXL could stabilize keratoconus, prevent myopia progression, and improve uncorrected distance visual acuity (UDVA). Despite the promising results, the studies had potential biases and a low number of randomized controlled trials (RCTs).The two primary methods of CXL are epithelium‐off (epi‐off) and epithelium‐on (epi‐on or transepithelial). Epi‐off CXL involves removing the corneal epithelium to allow riboflavin penetration, whereas epi‐on CXL retains the epithelium, reducing patient discomfort but potentially being less effective. NG et al. (2021) found no significant difference in outcomes between these methods, though epi‐on showed fewer side effects such as corneal haze.Accelerated CXL protocols have been developed to increase efficiency. Karam et al. (2023) compared these protocols, revealing that a 10‐minute protocol with 9 mW/cm2 UVA exposure provided better outcomes than a 5‐minute protocol with 18 mW/cm2. Accelerated methods are becoming more common due to their reduced treatment time.In pediatric cases, both conventional and accelerated CXL are effective, although the transepithelial method had a lesser impact, as concluded by Mahdavi Fard et al. (2020). Additionally, combined procedures known as CXL+ integrate CXL with other treatments like laser ablation. The Athens Protocol, developed by Dr. Kanellopoulos, combines topography‐guided laser ablation with CXL to address irregular astigmatism and coma in keratoconus patients.New riboflavin formulations and delivery methods, such as isotonic riboflavin and iontophoresis, have been developed to enhance riboflavin penetration and effectiveness. Glaukos' (Avedro) Mosaic System and the "sub400" protocol for ultrathin corneas are notable advancements, offering customized treatments based on individual corneal characteristics.

Progressive Keratoconus Treatment with Transepithelial Two-Step Phototherapeutic Keratectomy Combined with Corneal Crosslinking (CXL): Clinical Outcomes and Postoperative Management Including Potential Complications of the Modified Athens Protocol Designed for US-Approved Excimer Laser Specifications.

Objectives: To report a novel application within the USA of excimer ablation for the normalization of central corneal refractive irregularity, combined with higher fluence CXL in the effective management and visual rehabilitation of progressive keratoconus. Methods: 17 consecutive cases with progressive keratoconus were treated with corneal surface excimer laser ablation normalization using topography-guided (Contura) myopic ablation for customized corneal re-shaping with a 6 mm optical zone. The epithelial removal was accounted for by adding a -2.75 diopter correction to this topography-guided normalizing surface ablation followed by a second wavefront-optimized hyperopic excimer treatment of +2.75 diopters also with a 6 mm optical zone. The two sequential excimer ablations applied on the intact epithelium were followed by corneal crosslinking (CXL). Visual acuity, refraction, and keratoconus documentation via keratometry, topography, and pachymetry, as well as endothelial cell density were evaluated over 36 months. Results: Keratoconus stabilized in all cases. The severity and stage of keratoconus determined by the Amsler-Krumeich criteria improved for the OD from an average of 2.2 to 1. The median UDVA showed marked improvement at one-year follow-up (all values in LogMAR), from 0.8 preoperative to 0.3 at 12 months, and was stable through the 3 years at 0.3. The median CDVA increased from 0.5 to 0.1 at 1 year and was stable at 0.1 at 3 years. The average minimal corneal thickness decreased from 466 μm to 396 μm, as recorded the first year postoperatively, and then slightly increased to 405 μm at the 3-year follow-up. Conclusions: We introduce herein the initial clinical data for the use of a novel, off-label therapeutic excimer laser surface ablation application. It was designed to perform both epithelial removal and anterior corneal stroma reshaping and combined with CXL to apply the Athens Protocol CXL with US excimer laser-approved specifications.

Combined Photorefractive Keratectomy and Corneal Cross-Linking for Keratoconus and Ectasia: The Athens Protocol.

Customized photorefractive keratectomy with minimal tissue ablation combined with corneal cross-linking seems to be a long-term safe and effective strategy for anatomical and visual management of keratoconus, postsurgical ectasia, and other ectasia management. Multiple published studies, many with long-term follow-up, have supported the Athens Protocol and its various forms as a means to manage corneal ectatic disorders, which not only stabilize corneal shapes but also improve functional vision.

Concordance of keratoconus in monozygotic twins before and after combined corneal crosslinking/photorefractive keratectomy (Athens Protocol) using Scheimpflug and OCT tomography.

To describe the concordance of keratoconus (KC) expression in 2 pairs of monozygotic twins before and after a combined corneal crosslinking (CXL)/photorefractive keratectomy (PRK) procedure. Private ambulatory eye surgery unit. Retrospective interventional twin study. Two pairs of male monozygotic twins with KC were studied retrospectively. Improvement of flattest (K1) and steepest (K2) keratometry, index of height decentration (IHD), and corneal thickness at the thinnest point and corneal epithelial thickness measured by anterior segment optical coherence tomography and Scheimpflug tomography was compared between respective eyes of monozygotic twin siblings 1 to 5 years after the application of combined CXL and topography-guided PRK of part of the refractive error (the Athens Protocol). Significant improvement was noted in all the keratometric indices of all 8 eyes after the combined CXL/PRK procedure. The difference in K1, K2, IHD, corneal thickness at the thinnest point, and corneal epithelial thickness percentage improvement between the right eyes of each pair of twins was statistically significant 1 year and 5 years postoperatively (P < .05). Statistically significant discordance in the aforementioned parameters percentage improvement was similarly observed between the left eyes of each pair of twins (P < .05). Although a genetic predisposition in KC is well documented, the discordance in keratometric indices improvement after a CXL/PRK procedure between respective eyes of monozygotic twins suggests that environmental influences may contribute to the disease expression as well. Variable degree of synergy in a combined CXL/PRK procedure may also explain the aforementioned discordant improvement.

Refractive surgical treatment of akeratoconus patient using combined excimer laser ablation and corneal cross-linking (Athens protocol)

Refractive surgical treatment of akeratoconus patient using combined excimer laser ablation and corneal cross-linking (Athens protocol)

Ten-Year Outcomes of Progressive Keratoconus Management With the Athens Protocol (Topography-Guided Partial-Refraction PRK Combined With CXL).

To report the safety and long-term efficacy of topography-guided partial-refraction PRK combined with corneal cross-linking (CXL) (the Athens Protocol), refractive, topographic, and pachymetric changes of keratoconic eyes treated were studied. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refraction, keratometry, qualitative and quantitative assessment of corneal keratometric, and pachymetric properties recorded by topography and tomography were evaluated for 10 years postoperatively. A total of 144 eyes were followed up for a mean 128 ± 4 months (range: 120 to 146 months). Mean UDVA markedly improved at 1 year (0.19 ± 0.17 to 0.53 ± 0.21 decimal) with further improvement to 0.55 ± 0.19 decimal at 10 years. CDVA increased from 0.59 ± 0.21 to 0.80 ± 0.17 decimal at 1 year and further to 0.81 ± 0.19 decimal at 10 years. Corneal thickness decreased from 468.74 ± 35.05 to 391.14 ± 40.07 μm at 1 year (P < .01) and up to 395.42 ± 32.21 μm at 10 years. Steep keratometry decreased from 50.57 ± 2.80 to 45.87 ± 2.70 diopters (D) (P < .01) at 1 year and to 44.00 ± 3.22 D at 10 years. Maximum keratometry decreased from 53.43 ± 2.97 to 46.17 ± 1.18 D at 1 year and 44.75 ± 2.14 D at 10 years (P < .01). A total of 94.4% demonstrated ectasia stabilization and 3.5% showed progressive "overcorrection" or "hyperopic" shift. The Athens Protocol confirms long-term safety and efficacy for corneal ectasia and visual function. Most parameters had little change after 1 year, through year 10. [J Refract Surg. 2019;35(8):478-483.].

Long-Term Stability With the Athens Protocol (Topography-Guided Partial PRK Combined With Cross-Linking) in Pediatric Patients With Keratoconus.

To evaluate the safety, efficacy, and stability of topography-guided partial PRK combined with corneal cross-linking (CXL) (the Athens Protocol [AP]) in pediatric patients with keratoconus over a 4-year follow-up period. This prospective study included 39 keratoconic eyes of 21 patients younger than 18 years with clinical and imaging evidence of keratoconus progression. Partial topography-guided excimer laser ablation in conjunction with high-fluence CXL was performed in all patients according to the AP. Uncorrected distance visual acuity, corrected distance visual acuity, refraction, keratometry, endothelial cell density, topography, and tomography using both Scheimpflug and optical coherence tomography (OCT) were evaluated for 4 years postoperatively. At 4 years postoperative, there was significant improvement in mean uncorrected distance visual acuity from 0.51 ± 0.31 (decimal) to 0.65 ± 0.26 (decimal; P < 0.05). Mean corrected distance visual acuity improved from 0.71 ± 0.22 (decimal) preoperatively to 0.81 ± 0.19 (decimal; P < 0.05), respectively. Mean flat keratometry (K1) and mean steep keratometry (K2) readings reduced from 44.95 ± 3.71 D and 49.32 ± 5.05 D, respectively, preoperatively to 43.14 ± 2.95 D and 46.28 ± 4.87 D, respectively, (P < 0.05) at 4 years. The mean anterior maximum keratometry (Kmax) reading reduced from 56.81 ± 2.94 D preoperatively to 48.11 ± 3.17 D at 48 months. The mean index of height decentration was 0.105 ± 0.054 μm preoperatively and 0.049 ± 0.024 (P < 0.05) at 4 years postoperative. Mean preoperative corneal thickness at the thinnest point was 436.7 ± 42.6 μm preoperatively, 392.50 ± 45.68 μm at 12 months postoperative, and 418.42 ± 17.01 μm at 4-year follow-up. Late-onset deep corneal haze, a potential intrinsic complication of this technique in pediatric patients, was encountered in 2 cases at least 1 year after the procedure. Long-term results of the AP seem to be safe and effective in pediatric patients, with marked improvement in visual function and keratometric symmetry indices.

The impact of keratoconus treatment with the Athens Protocol (partial topography-guided photorefractive keratectomy combined with higher-fluence corneal collagen cross-linking) on quality of life: a long-term study.

PurposeThe aim of this study was to evaluate the health-related quality of life (HRQoL) before and after the management of keratoconus (KCN) with Combined Topography-Guided Transepithelial partial photorefractive keratectomy (PRK) and corneal Cross-Linking: the Athens Protocol.Patients and methodsThirty-four consecutive patients treated for progressive KCN were selected for retrospective telephone interview and individual questionnaire submission. A disease-specific HRQoL questionnaire was administered before and after the Athens Protocol intervention, using the following administrative questionnaires: National Eye Institute Visual Function Questionnaire (NEI VFQ) 25/39 and IVI-28. The disease grade was ranked according to the Amsler–Krumeich classification (KCN severity). Reliability of collected data was evaluated with Cronbach’s α test.ResultsPatients’ age ranged from 15 to 51 years at the time of the operation. Mean time before the operation during which the questionnaires were administered was 52±6 months. General visual acuity, psychological well-being, and driving ability showed significant improvement. Younger keratoconic patients tend to have more enhanced psychological status and to cope better with difficulties in everyday activities (prior to operation) than older patients.ConclusionThe Athens Protocol treatment has been proven to be beneficial to patients in a large number of aspects.

Management of progressive keratoconus with partial topography-guided PRK combined with refractive, customized CXL - a novel technique: the enhanced Athens protocol.

PurposeTo report a novel application of partial topography-guided photorefractive keratectomy combined with topographically customized, higher fluence, and variable pattern corneal cross-linking applied on the same day of the treatment of keratoconus.MethodsA topography-guided partial photorefractive keratectomy treatment of maximum 30 µm over the thinnest cone area was applied initially followed by a 7 mm, 50 µm phototherapeutic keratectomy treatment to address epithelial removal. 0.02% Mitomycin C was applied for 20 seconds and then the exposed stroma was soaked with 0.1% riboflavin solution for 5 minutes. The cornea was then treated with a customized, variable-pattern and 20 mW/cm2 fluence for a total of 5–10 J, and up to 15 J of energy was delivered with the KXL-II device employing an active tracker. The center of the pattern that received the 15 J was topography-matched with the thinnest area of the cone. Visual acuity, refractive error, cornea clarity, keratometry, topography, pachymetry with a multitude of modalities and endothelial cell density were evaluated over 36 months.ResultsKeratoconus was stabilized in all cases. The severity of keratoconus stage by Amsler– Krumeich criteria improved from an average of 3.2 (1–4) to 1.8 (0–3). Uncorrected distance visual acuity changed from preoperative 20/80 to 20/25 at 6 months. A maximum astigmatic reduction of 7.8 D (5.3–15.6), and a significant cornea surface normalization (an index of height decentration improvement from 0.155 [±0.065] to 0.045 [±0.042]) were achieved by 1 month and remained relatively stable for 36 months postoperatively. Two cases delayed full reepithelialization for up to 9 days.ConclusionThis paper introduces a novel technique in order to maximize the refractive normalization effect along with ectasia stabilization in young keratoconus patients. This may facilitate the use of less tissue ablation, in comparison to utilizing a homogeneous UV light beam for corneal cross-linking in Athens Protocol cases. It broadens the number of potential candidate cases that would have been limited to employ this technique due to tissue thickness limitations.

Topography-guided photorefractive keratectomy combined with accelerated corneal collagen cross-linking (The Athens Protocol) for keratoconus

Objective The aim was to evaluate corneal changes after topography-guided partial photorefractive keratectomy (PRK) combined with accelerated corneal collagen cross-linking (CXL) (the Athens protocol) in progressive keratoconus with Pentacam Scheimpflug imaging. Background Keratoconus is a bilateral noninflammatory progressive corneal thinning that results in irregular astigmatism and progressive myopia. Topography-guided partial PRK combined with CXL (The Athens Protocol) has been developed not only to arrest progression of keratoconus but also to offer the patients functional vision. Patients and methods This prospective study included 20 eyes that underwent topography-guided partial PRK combined with accelerated CXL (The Athens Protocol). Preoperative and postoperative assessments included visual acuity, slit lamp evaluation, and Pentacam. All investigation and examination were done during the period from June 2017 to June 2018. Results All study parameters demonstrated a statistically significant improvement with uncorrected distance visual acuity of 0.55 ± 0.29 Snellen line postoperatively vs. 0.33 ± 0.24 Snellen line preoperatively and best-corrected visual acuity of 0.73 ± 0.25 Snellen line postoperatively vs. 0.61 ± 0.27 Snellen line preoperatively, with a P value of 0.005; flat keratometry of 44.76 ± 1.64 D postoperatively vs. 45.29 ± 2.01 D preoperatively and steep keratometry of 46.55 ± 2.09 D vs. 47.68 ± 2.42 D, preoperatively, with a P value of less than 0.001; mean postoperative index of surface variance of 50.70 ± 18.34 postoperatively vs. 65.25 ± 29.29 preoperatively, with P value less than 0.001; and mean postoperative index of height decentration of 0.053 ± 0.033 postoperatively vs. 0.091 ± 0.052 preoperatively, with P value less than 0.001. Conclusion Topography-guided partial PRK combined with accelerated CXL (The Athens Protocol) is a relatively new and revolutionary procedure aimed at stabilization of corneal ectatic disorders and achieving a good visual quality. Longer duration of follow-up and a larger sample may further provide more reliable results.

Efficacy of Combined Phototherapeutic Keratectomy, Wavefront-optimized Photorefractive Keratectomy and Corneal Collagen Crosslinking in the Management of Progressive Keratoconus over One-year Follow-up: Modified Athens Protocol

Efficacy of Combined Phototherapeutic Keratectomy, Wavefront-optimized Photorefractive Keratectomy and Corneal Collagen Crosslinking in the Management of Progressive Keratoconus over One-year Follow-up: Modified Athens Protocol

Higher incidence of steroid-induced ocular hypertension in keratoconus.

BackgroundTo compare intraocular pressure (IOP) changes following topical dexamethasone administration for 1 month in keratoconic versus normal eyes.MethodsThis is a retrospective, single-center, non-randomized case series evaluation of 350 eyes. Two groups were formed: normal/control Group A (nA =73), eyes that underwent excimer laser photorefractive keratectomy; and keratoconic (KCN) Group B (nB =277), eyes that were subjected to partial laser photorefractive keratectomy combined with collagen cross-linking (The Athens Protocol). All eyes received the same post-operative regimen of topical dexamethasone 0.1 % for at least 1 month. Goldmann applanation tonometry IOP readings and central corneal thickness (CCT) measurements were monitored. Cases with induced ocular hypertension (OHT, defined as post-operative IOP higher than 21 mmHg), were identified and correlated to refractive procedure, gender, and corneal thickness.ResultsAt 4 weeks postoperatively, OHT was noted on 27.4 % (20 /73 eyes) in Group A, and 43.7 % (121 /277 eyes) in KCN Group B, (p <0.01). Six months post-operatively (following 5-months of discontinuing topical dexamethasone treatment and commencing treatment of IOP-lowering medications), OHT rate was 1.8 % in Group A and 3.9 % in the KCN Group B.ConclusionThis study demonstrates a potentially significant pre-disposition of keratoconic eyes to the development of steroid-induced OHT.

Simultaneous Topography-guided Surface Ablation with Collagen Cross-linking for Keratoconus

ABSTRACT Purpose In this article, we present the results of eight eyes of patients who underwent combined same-day partial topography-guided surface ablation followed by accelerated collagen cross-linking (CXL) procedure at Care-Vision Laser Centers to achieve stabilization of corneal ectasia and enhance visual rehabilitation in keratoconus. Materials and methods A retrospective nonrandomized review of 8 eyes of 6 patients who underwent the Athens Protocol for progressive keratoconus. Each patient underwent topography-guided ablation followed by CXL procedure. Follow-up Follow-up was done on day 1, day 7, and then at 1, 3, 6, and 12 months. Results There was a rapid and significant improvement in uncorrected visual acuity and best-corrected visual acuity in 100% eyes, a reduction of keratometric values, and symmetry between vertical hemimeridians. Topographic evaluation showed a marked improvement in irregularity. There were no signs of keratoconic progression noted in any of the eyes on last follow-up. No adverse events were reported in any patient. Conclusion Simultaneous surface ablation + CXL seems to be a promising treatment capable of offering patients functional vision and halting progression of the disorder. Precis Simultaneous topography-guided custom ablation treatment and photorefractive keratectomy with CXL offers keratoconic patients intolerant to contact lenses both stabilization of the cornea and improved functional vision with spectacles correction. How to cite this article Karmona L, Sela T, Franco O, Shoshani A, Munzer G, Kaiserman I. Simultaneous Topography-guided Surface Ablation with Collagen Cross-linking for Keratoconus. Int J Kerat Ect Cor Dis 2016;5(2):71-76.

Epithelial remodeling after partial topography-guided normalization and high-fluence short-duration crosslinking (Athens protocol): Results up to 1 year

To compare epithelial remodeling in keratoconic eyes that had photorefractive keratectomy and corneal collagen crosslinking (Athens protocol) with that in untreated keratoconic eyes and healthy eyes. Private clinical practice, Athens, Greece. Comparative case series. Fourier-domain anterior segment optical coherence tomography (AS-OCT) was used to obtain in vivo 3-dimensional epithelial thickness maps and center, superior, inferior, maximum, minimum, mean, midperipheral, and variability data. Group A comprised 175 treated keratoconic eyes (Athens protocol); Group B, 193 untreated keratoconic eyes; and Group C, 160 healthy eyes. The 1-year mean center epithelial thickness in Group A was 47.78 μm ± 7.36 (SD) (range 33 to 64 μm). At the first clinical visit, it was 52.09 ± 6.80 μm (range 36 to 72 μm) in Group B and 52.54 ± 3.23 μm (range 45 to 59 μm) in Group C. The mean thickness range in Group A at 1 year was -19.94 ± 7.21 μm (range -6 to -34 μm). It was -21.83 ± 12.07 μm (range -4 to -66 μm) in Group B and -6.86 ± 3.33 μm (range -3 to -29 μm) in Group C. The mean topographic thickness variability in Group A at 1 year was 4.64 ± 1.63 μm (range 1.6 to 8.1 μm) (P<.05). It was 5.77 ± 3.39 μm (range 1.3 to 17.8 μm) in Group B and 1.59 ± 0.79 μm (range 0.6 to 5.6 μm) in Group C. Anterior segment OCT indicated a thinner and more homogeneous remodeled epithelium in the keratoconic eyes treated using the Athens protocol. Dr. Kanellopoulos is a consultant to Alcon Surgical, Inc.; Wavelight Laser Technologie AG; Avedro, Inc.; and i-Optics Optikgeräte GmbH. Dr. Asimellis has no financial or proprietary interest in any material or method mentioned.

Simultaneous corneal crosslinking and surface ablation combined with phakic intraocular lens implantation for managing keratoconus.

To assess the efficacy and stability of simultaneous topography-guided photorefractive keratectomy (PRK) and crosslinking (Athens protocol) followed by phakic intraocular lens (IOL) implantation for managing keratoconus. Ain-Shams University, Cairo, Egypt. Prospective non-randomized study. All patients underwent topography-guided PRK followed immediately by collagen crosslinking (Athens protocol), 2-4 months later, eyes were implanted with either an iris claw or an angle-supported phakic IOL. Statistical analysis was performed with SigmaPlot software version 11.0 (Systat Software, Inc.). This study evaluated 22 eyes of 14 patients. Follow-up interval was at least 6 months. A Veriflex phakic IOL was implanted in 14 eyes (63.6 %), and a Cachet phakic IOL was implanted in 8 eyes (36.4 %). The mean preoperative keratometric reading (45.57 ± 1.51 D) was significantly reduced at 3 months and at 6 months after treatment (43.82 ± 1.98 D, P < 0.001). The mean spherical equivalent was significantly reduced from -9.08 ± 2.5 to -0.69 ± 0.67 D, P = <0.001. The mean UCVA improved from 1.24 ± 0.49 to 0.37 ± 0.08 logMAR. The mean corrected distance visual acuity (CDVA; logMAR) improved from 0.69 ± 0.3 preoperatively to 0.35 ± 0.01 postoperatively (P = <0.001). At last follow-up, all eyes could achieve CDVA of 0.3 or better. The difference between pre- and postoperative endothelial cell counts was not statistically significant. Combining phakic IOLs and the Athens protocol improved and stabilized visual performance in patients with keratoconus. These results justify a future, large-scale study with a longer follow-up.

Corneal refractive power and symmetry changes following normalization of ectasias treated with partial topography-guided PTK combined with higher-fluence CXL (the Athens Protocol).

To investigate preoperative and postoperative anterior and posterior keratometry and simulated corneal astigmatism in keratoconic eyes treated with collagen cross-linking combined with anterior surface normalization by partial topography-guided excimer ablation (the Athens Protocol). Anterior and posterior corneal keratometry were measured by Scheimpflug imaging for 267 untreated keratoconic eyes. Following treatment, they were assessed 1 year postoperatively. Before treatment, average anterior keratometric value was 47.06 ± 6.02 diopters (D) for flat and 51.24 ± 6.75 D for steep. The posterior keratometric values were -6.70 ± 0.99 D (flat) and -7.67 ± 1.15 D (steep). Anterior astigmatism was on average with-the-rule (-1.97 ± 6.21 D), whereas posterior astigmatism was against-the-rule (+0.53 ± 1.02 D). The posterior and anterior astigmatism were highly correlated (r(2) = 0.839). After treatment, anterior keratometric values were 43.97 ± 5.81 D (flat) and 46.55 ± 6.82 D (steep). Posterior keratometric values were -6.58 ± 1.05 D (flat) and -7.69 ± 1.22 D (steep). Anterior astigmatism was on average with-the-rule (-1.56 ± 3.80 D), whereas posterior astigmatism was against-the-rule (+0.45 ± 1.29 D). The statistically significant (P < .05) keratometric changes indicated anterior surface flattening -3.09 ± 2.67 D (flat) and -4.19 ± 2.96 D (steep). The posterior keratometric changes were not statistically significant (P > .05). Before treatment, there was a strong correlation between posterior and anterior corneal astigmatism. After treatment, statistically significant anterior keratometric values flattened. The posterior surface keratometric values did not demonstrate statistically significant postoperative change: there was minimal posterior change, despite the significant anterior surface normalization.

Keratoconus management: long-term stability of topography-guided normalization combined with high-fluence CXL stabilization (the Athens Protocol).

To investigate refractive, topometric, pachymetric, and visual rehabilitation changes induced by anterior surface normalization for keratoconus by partial topography-guided excimer laser ablation in conjunction with accelerated, high-fluence cross-linking. Two hundred thirty-one keratoconic cases subjected to the Athens Protocol procedure were studied for visual acuity, keratometry, pachymetry, and anterior surface irregularity indices up to 3 years postoperatively by Scheimpflug imaging (Oculus Optikgeräte GmbH, Wetzlar, Germany). Mean visual acuity changes at 3 years postoperatively were +0.38 ± 0.31 (range: -0.34 to +1.10) for uncorrected distance visual acuity and +0.20 ± 0.21 (range: -0.32 to +0.90) for corrected distance visual acuity. Mean K1 (flat meridian) keratometric values were 46.56 ± 3.83 diopters (D) (range: 39.75 to 58.30 D) preoperatively, 44.44 ± 3.97 D (range: 36.10 to 55.50 D) 1 month postoperatively, and 43.22 ± 3.80 D (range: 36.00 to 53.70 D) up to 3 years postoperatively. The average Index of Surface Variance was 98.48 ± 43.47 (range: 17 to 208) pre-operatively and 76.80 ± 38.41 (range: 7 to 190) up to 3 years postoperatively. The average Index of Height Decentration was 0.091 ± 0.053 μm (range: 0.006 to 0.275 μm) preoperatively and 0.057 ± 0.040 μm (range: 0.001 to 0.208 μm) up to 3 years postoperatively. Mean thinnest corneal thickness was 451.91 ± 40.02 μm (range: 297 to 547 μm) preoperatively, 353.95 ± 53.90 μm (range: 196 to 480 μm) 1 month postoperatively, and 370.52 ± 58.21 μm (range: 218 to 500 μm) up to 3 years postoperatively. The Athens Protocol to arrest keratectasia progression and improve corneal regularity demonstrates safe and effective results as a keratoconus management option. Progressive potential for long-term flattening validates using caution in the surface normalization to avoid overcorrection.

Long-term Improvement after the Athens Protocol for Advanced Keratoconus with Significant Ectasia Progression in the Fellow Eye

ABSTRACT To describe the long-term result of the Athens protocol (custom topography-guided advanced surface ablation followed by riboflavin-UVA collagen cross-linking in the same day) for progressive advanced keratoconus in the left eye, while the fellow right eye first presented with relatively mild keratoconus that was treated with a more conservative therapeutic approach of continuous contact lenses use with the goal for ectasia stabilization. Five years after the Athens protocol, a regression of over 10D (diopters) was observed on the sagittal curvature with significant regularization of corneal shape and improvement of distance corrected visual acuity (DCVA) in the left eye. The right eye, which was treated more conservatively, had an over 12D increase on sagittal curvature along with significant distortion of the corneal shape and reduction of DCVA. How to cite this article Pereira LC, Siqueira R, Valbon B, Santos R, Dawson D, Ambrósio R, Siqueira JA. Long-term Improvement after the Athens Protocol for Advanced Keratoconus with Significant Ectasia Progression in the Fellow Eye. Int J Kerat Ect Cor Dis 2014;3(1):40-43.

Comparison of Placido disc and Scheimpflug image-derived topography-guided excimer laser surface normalization combined with higher fluence CXL: the Athens Protocol, in progressive keratoconus

BackgroundThe purpose of this study was to compare the safety and efficacy of two alternative corneal topography data sources used in topography-guided excimer laser normalization, combined with corneal collagen cross-linking in the management of keratoconus using the Athens protocol, ie, a Placido disc imaging device and a Scheimpflug imaging device.MethodsA total of 181 consecutive patients with keratoconus who underwent the Athens protocol between 2008 and 2011 were studied preoperatively and at months 1, 3, 6, and 12 postoperatively for visual acuity, keratometry, and anterior surface corneal irregularity indices. Two groups were formed, depending on the primary source used for topoguided photoablation, ie, group A (Placido disc) and group B (Scheimpflug rotating camera). One-year changes in visual acuity, keratometry, and seven anterior surface corneal irregularity indices were studied in each group.ResultsChanges in visual acuity, expressed as the difference between postoperative and preoperative corrected distance visual acuity were +0.12 ± 0.20 (range +0.60 to −0.45) for group A and +0.19 ± 0.20 (range +0.75 to −0.30) for group B. In group A, K1 (flat keratometry) changed from 45.202 ± 3.782 D to 43.022 ± 3.819 D, indicating a flattening of −2.18 D, and K2 (steep keratometry) changed from 48.670 ± 4.066 D to 45.865 ± 4.794 D, indicating a flattening of −2.805 D. In group B, K1 (flat keratometry) changed from 46.213 ± 4.082 D to 43.190 ± 4.398 D, indicating a flattening of −3.023 D, and K2 (steep keratometry) changed from 50.774 ± 5.210 D to 46.380 ± 5.006 D, indicating a flattening of −4.394 D. For group A, the index of surface variance decreased to −5.07% and the index of height decentration to −26.81%. In group B, the index of surface variance decreased to −18.35% and the index of height decentration to −39.03%. These reductions indicate that the corneal surface became less irregular (index of surface variance) and the “cone” flatter and more central (index of height decentration) postoperatively.ConclusionOf the two sources of primary corneal data, the Scheimpflug rotating camera (Oculyzer™) for topography-guided normalization treatment with the WaveLight excimer laser platform appeared to provide more statistically significant improvement than the Placido disc topographer (Topolyzer™). Overall, the Athens protocol, aiming both to halt progression of keratoconic ectasia and to improve corneal topometry and visual performance, produced safe and satisfactory refractive, keratometric, and topometric results. The observed changes in visual acuity, along with keratometric flattening and topometric improvement, are suggestive of overall postoperative improvement.

Long-term Improvement after the Athens Protocol for Advanced Keratoconus with Significant Ectasia Progression in the Fellow Eye

ABSTRACT To describe the long-term result of the Athens protocol (custom topography-guided advanced surface ablation followed by riboflavin-UVA collagen crosslinking in the same day) for progressive advanced keratoconus in the left eye, while the fellow right eye first presented with relatively mild keratoconus that was treated with a more conservative therapeutic approach of continuous contact lenses use with the goal for ectasia stabilization. Five years after the Athens protocol, a regression of over 10 D (diopters) was observed on the sagittal curvature with significant regularization of corneal shape and improvement of distance corrected visual acuity (DVCA) in the left eye. The right eye, which was treated more conservatively, had an over 12 D increase on sagittal curvature along with significant distortion of the corneal shape and reduction of DCVA. How to cite this article Siqueira JA, Dias LC, Siqueira R, Valbon B, Santos R, Dawson D, Ambrósio Jr R. Longterm Improvement after the Athens Protocol for Advanced Keratoconus with Significant Ectasia Progression in the Fellow Eye. J Kerat Ect Cor Dis 2013;2(3):143-146.