Fungal Keratitis: Diagnosis, Management, and Recent Advances.

Fungal keratitis is one of the major causes of microbial keratitis that may lead to corneal blindness. Many problems related to diagnosis and therapy are encountered in fungal keratitis, including difficulty in obtaining laboratory diagnoses and the availability and efficacy of antifungal medications. Intensive and prolonged use of antifungal topical preparations may not be enough. The use of antifungal medications is considered the main treatment for fungal keratitis. It is recommended to start antifungal therapy after confirmation of the clinical diagnosis with a smear or positive cultures. Topical application of antifungal medications is a mainstay for the treatment of fungal keratitis; however, systemic, intra-stromal, or intra-cameral routes may be used. Therapeutic keratoplasty is the main surgical procedure approved for the management of fungal keratitis with good success rate. Intrastromal corneal injection of antifungal medications may result in steady-state drug levels within the corneal tissue and prevent intervals of decreased antifungal drug concentration below its therapeutic level. In cases of severe fungal keratitis with deep stromal infiltration not responding to treatment, intracameral injection of antifungal agents may be effective. Collagen cross-linking has been proposed to be beneficial for cases of fungal keratitis as a stand-alone therapy or as an adjunct to antifungal medications. Although collagen cross-linking has been extensively studied in the past few years, its protocol still needs many modifications to optimize UV fluence levels, irradiation time, and concentration of riboflavin to achieve 100% microbial killing.

Intraocular pressure after combined photorefractive keratectomy and corneal collagen cross-linking for keratoconus.

PURPOSE: The purpose of this prospective study was to evaluate the effect of combined photorefractive keratectomy (PRK) and corneal collagen cross-linking (CXL) on intraocular pressure (IOP) in patients with keratoconus (KC). METHODS: We included 64 eyes of 34 patients (19 males and 15 females; age: 19-40y) with stages 1-2 keratoconus which had undergone combined wavefront-optimized photorefractive keratectomy and corneal collagen cross linking. Two other groups of patients were added as controls: the PRK group including 110 eyes of 57 patients (23 males and 34 females; age: 18-44y) which had undergone wavefront-optimized photorefractive keratectomy for myopic refractive errors, and the CXL group including 36 eyes of 23 patients (14 males and 9 females; age: 12-38y) with keratoconus, not filling the inclusion criteria for combined PRK and CXL, which had undergone corneal collagen cross-linking. IOP was recorded preoperatively and postoperatively at 3, 6 and 12 months follow-up visits. RESULTS: Preoperative IOP in both CXL (12.1 ± 2.53 mmHg) and PRK + CXL (13.2 ± 2.50 mmHg) groups was significantly lower than PRK group (15.8 ± 3.10 mmHg) (F = 30.505, p < 0.001). At 3 months postoperatively, IOP showed no statistically significant difference between the three studied groups (F = 1.821, p = 0.164). At 6 months postoperatively, IOP in the CXL group (14.6 ± 2.64 mmHg) was significantly higher than both PRK (13.4 ± 2.27 mmHg) and PRK + CXL (13.3 ± 2.62 mmHg) groups (F = 3.721, p = 0.026). At 12 months postoperatively, IOP in the CXL group (14.3 ± 2.69 mmHg) was significantly higher than the PRK group (13.2 ± 2.23 mmHg) and was higher than PRK + CXL group (13.3 ± 2.59 mmHg) although not statistically significant (F = 3.393, p = 0.035). Regarding the percent of change from preoperative IOP, a statistically significant difference between the three studied groups was detected at 3, 6 and 12 months postoperatively (H = 117.459, 109.303, 122.694 respectively, p < 0.001). The median percent of change from preoperative IOP in the PRK group was -16.7%, -15%, and -16.7%, in the CXL group was + 14.3%, + 19.4%, and + 19.1%, while in PRK + CXL group was 0% at 3, 6 and 12 months postoperatively. (Post-hoc power analysis 75%). CONCLUSIONS: Combined PRK and CXL in patients with KC shows no significant effect on IOP, in contrast to either procedure performed separately.

Prevalence of diabetic retinopathy in patients with diabetes in Alexandria and North-West Delta, Egypt.

PURPOSE: The purpose of this research was to estimate the prevalence of DR in Alexandria and the North-West Delta region. METHODS: All diabetic patients attending the general ophthalmology clinics (Group 1), diabetic internal medicine clinics (Group 2), or reached out in the local communities (Group 3) were eligible to participate. Fundus photographs were graded according to the Scottish DR grading system by three independent UK-certified graders. Adjudication by a consultant was done when needed. RESULTS: Out of 11,033 screened patients, 10,811 had a gradable fundus photograph in at least one eye and were included. The numbers of cases in groups 1, 2 and 3 were 3940, 2826, and 4045, respectively. Males represented 38.35% of the cases. Mean age was 55 ± 12.63. For the whole sample, groups 1, 2 and 3, the DR prevalence was 32.49, 46.4%, 29.13%, and 21.29%, respectively. The prevalence of proliferative DR (grade R4) was 6.16%, 11.83%, 5.02%, and 1.45%, respectively, and of referable maculopathy (Grade M2) was 19.95%, 31.42%, 15.92%, and 11.59%, respectively. In univariate analysis, older age, higher random blood glucose, and longer DM duration were associated with a higher risk of both DR and referable diabetic maculopathy. This association was maintained in multivariate analysis for the high random blood glucose level and the longer duration of DM (but not for the older age). CONCLUSION: A significantly higher prevalence of DR, grades R4 and M2 was found in the hospital-recruited patients than in diabetics from the local communities.

Comparison between three different high fluence UVA levels in corneal collagen cross-linking for treatment of experimentally induced fungal keratitis in rabbits.

INTRODUCTION: The aim of this study was to compare the efficacy of Photo-Activated Chromophore for Keratitis - Corneal Collagen Cross-linking (PACK-CXL) of three different total UVA fluence levels and topical voriconazole in treatment of fungal keratitis experimentally induced in rabbits. METHODS: This is an interventional experimental study including both eyes of 16 rabbits (32 eyes). Fungal keratitis was induced by intrastromal injection of Fusarium Solani into the cornea. The rabbits were then divided into four groups (8 eyes for each) from which group A received Voriconazole eye drops and considered as control group. Group B, C, D received single PACK-CXL session with total fluence levels of 7.2, 10.0 and 15.0 J/cm2 for each respectively. Daily clinical examination was recorded and all corneas were removed for microbiology and histopathology on day ten. RESULTS: The mean clinical signs score eyes treated with high fluence PACK-CXL showed evident clinical improvement from fourth to tenth day of treatment. This improvement was equivalent to that of Voriconazole treatment. The results showed better improvement with increasing the UVA total fluence levels but this difference was not statistically significant (P < 0.05). Similarly, the median CFU/ml declined on increasing UVA fluence but with no statistically significant values. Histopathological examination revealed better improvement of inflammatory signs on higher fluence levels compared to lower ones. CONCLUSIONS: High intensity PACK-CXL (30 mW/cm2) was as effective as Voriconazole in the treatment of fungal keratitis in rabbits. Increasing the fluence of UVA was associated with slightly better clinical outcomes with no added risks. More clinical studies are needed to confirm these results.

Descemet's Membrane Endothelial Keratoplasty and Phacoemulsification: Combined versus Sequential Surgery.

PURPOSE: To compare the outcomes of Descemet's membrane endothelial keratoplasty (DMEK) combined with phacoemulsification versus DMEK following phacoemulsification. METHODS: In this interventional retrospective comparative nonrandomized case series study, patients with Fuchs endothelial corneal dystrophy (FECD) with either cataract or previous cataract surgery with intraocular lens (IOL) implantation were assigned to one of the two groups according to lens status. Group 1 included patients who had cataract and FECD and would undergo triple procedure (phacoemulsification with IOL implantation and DMEK), whereas Group 2 included patients who had FECD and had phacoemulsification with IOL implantation earlier and would undergo DMEK only as a sequential procedure. RESULTS: Postoperative best corrected visual acuity (BCVA) in both groups at 1 week, 1 month, 3 months, and 6 months revealed a statistically nonsignificant difference between the two groups with mean logMAR BCVA at 6 months of 0.07 ± 0.18 and 0.07 ± 0.19 in Group 1 and Group 2, respectively (P > 0.05). The drop in endothelial cell density by the end of the 6th postoperative month was by 39.44% ±7.92 and 38.73% ±8.10 in the triple-procedure group and DMEK only group, respectively (P = 0.005). Total postoperative complications rate and the rebubbling rate were statistically similar between both groups with 13.5% and 12.5% rebubbling rate in Group 1 and Group 2, respectively (P > 0.05). CONCLUSION: Visual outcomes, endothelial cell loss, and rebubbling rate are comparable when DMEK is combined with phacoemulsification or when it is performed as staged procedure, without statistically significant difference in the outcomes.

Clinical Validation of the Automated Characterization of Cone Size and Center in Keratoconic Corneas.

PURPOSE: To evaluate an automated method for detecting the cone shape characteristics and to assess the cornea specialists' subjective variability of these measures using different maps. METHODS: Topographic images of the anterior and posterior surface of each eye were presented to 12 clinicians in two different types of map: tangential curvature and relative elevation to the best-fit sphere. They were asked to mark the cone center and its boundaries in the two maps without knowing that they belonged to the same patient. The results between the maps were compared to assess the subjective variability dependent on the map type and the automated method was compared against both estimations to assess its accuracy. RESULTS: Considering the results of anterior and posterior surfaces, there was low agreement between the cone center estimations using different types of maps for 10 of the 12 cases (P < .05), whereas the comparison between the automated method and the two map estimations did not show differences in 11 of the 12 cases (P > .05). There was high variability, up to 55%, among clinicians' estimations of the cone area. The results of the automated method were within the range of the expert's estimations. CONCLUSIONS: An objective, mathematically derived method of determining morphological dimensions of the cone was consistent with clinicians' evaluations. Although there was high variability among the experts' subjective estimates, which were highly influenced by the type of map, the objective method provided a reliable evaluation of the keratoconus shape independent of maps or color scale. [J Refract Surg. 2021;37(6):414-421.].

Objective and subjective evaluation of trifocal diffractive intraocular Lens after cataract extraction with phacoemulsification: a prospective clinical study.

BACKGROUND: This study aimed to assess visual outcomes, quality of vision and patients' satisfaction of a trifocal diffractive intraocular lens after cataract surgery with phacoemulsification. RESULTS: The study included 36 eyes that underwent implantation of trifocal diffractive intraocular lens (IOL). The residual mean postoperative spherical equivalent was - 0.40 ± 0.29 diopters. Mean Uncorrected distance visual acuity was 0.80 ± 0.16 decimal (snellen equivalent 25 ft) while mean Uncorrected intermediate visual acuity was 0.82 ± 0.31 decimal (snellen equivalent 25 ft) and mean Uncorrected near visual acuity (UCNVA) was 0.87 ± 0.20 decimal (snellen equivalent 23 ft). In defocus curve, there was infinitesimal gradual change between the three foci. Contrast sensitivity was just below the inferior limit of normal. CONCLUSION: Trifocal diffractive IOL created a true intermediate focus proved by VA and defocus curve and better quality of vision assessed by contrast sensitivity and high order aberration. Moreover, it was safe and effective for correcting distance and near vision in these patients. Most of the patients were very satisfied and achieved spectacle independence. TRIAL REGISTRATION: Registration number and date: NCT04465279 on July 10, 2020.

Corneal endothelial cells changes in different stages of Keratoconus: a multi-Centre clinical study.

PURPOSE: To assess the corneal endothelial cells morphology and count in keratoconus patients and their correlation with different stages of keratoconus. METHODS: Prospective non randomized multi-centric clinical study included 150 eyes of 150 keratoconus patients. Four centers in Egypt participated in this study included: Departments of Ophthalmology in Alexandria University, Tanta University and Port Said University and Alex I-Care hospital. Pentacam (Wavelight Oculyzer II) and specular microscopy (Tomey EM-3000) were done to all eyes. Keratoconic eyes were classified according to Amsler classification into stage 1, 2 and 3. Stage 1 included 99 eyes, stage 2 included 32 eyes & stage 3 included 19 eyes. RESULTS: The mean age of keratoconus patients was 24.07 ± 6.154 years. Forty five cases were males (30%) and 105 cases were females (70%). There was statistically significant difference in endothelial cell density (p < 0.001) and coefficient of variation (p = 0.012) between different stages of keratoconus eyes. Regarding cell surface area, there was statistically significant difference in cell surface area between different stages of keratoconus eyes (p < 0.001). In addition, for cell morphology, there was statistically significant difference between different stages of keratoconus eyes (p < 0.001). CONCLUSIONS: Qualitative and quantitative structural changes were seen in endothelial cells of keratoconus eyes by using specular microscopy. For stages 1 and 2, keratoconus may not affect the corneal endothelim significantly. The endothelium in stage 3 shows significant changes regarding polymegathism and pleomorphism.

Ten years experience of corneal collagen cross-linking : An observational study of 6120 cases.

PURPOSE: To study the effect of corneal collagen cross-linking (CXL) using riboflavin and ultraviolet rays on cases of corneal ectasia in keratoconus cases, post-laser-assisted in situ keratomileusis ectasia, and pellucid marginal degeneration and to present its long-term results over many years. METHODS: This study was conducted throughout 10 "years" experience in corneal collagen CXL, including 6120 cases. The study consists of two parts: a retrospective and a prospective part. All patients in the retrospective part were operated by epi-off, while in the prospective part, the epi-on procedure was used. Also, other machines were used as Peschke Vario, Peschke Phoenix, and different types of riboflavin. The results were analyzed using SPSS. RESULTS: The study showed stabilization ectasia in 95% of cases using our standard protocol, and this was proved by topography, pachymetry, refraction, and visual acuity. The effect of CXL was continued in 20% of cases, over a period of 3-5 years, some cases needed to repeat CXL due to the progression of corneal ectasia after cross-linking, in six eyes, that were rubbing their eyes and/or hormonal disturbance. CONCLUSION: Corneal collagen cross-linking CXL is an effective method to prevent the progression of corneal ectasia, whether primary or post-laser-assisted in situ keratomileusis, and the effect was stable over the years of study.

A novel Q-value-based nomogram for single intracorneal ring segment implantation versus standard manufacturer's nomogram combined with accelerated cross-linking for treatment of keratoconus: a randomized controlled trial.

PURPOSE: To compare the efficacy of implanting a single Keraring segment according to a novel Q-value-based nomogram (QN) to that of segment implantation according to the manufacturer's standard nomogram (SN), for keratoconus treatment. METHODS: This was a prospective, randomized controlled trial of 104 patients (104 eyes) with Amsler-Krumeich grade 1 or 2 keratoconus, and type 1 or 2 cone asymmetry determined according to manufacturer's classification. They were randomly distributed into two groups: group A patients (n = 52) underwent Keraring implantation according to the SN, and group B patients (n = 52) underwent implantation of a single (210° arc-length) Keraring segment according to the QN. Both treatments were combined with accelerated transepithelial cross-linking, and follow-up was 6 months. Main outcome measures were preoperative and postoperative visual acuity, subjective refraction and corneal topography. RESULTS: At postoperative month 6, group B exhibited statistically significantly higher values of mean uncorrected distance visual acuity (UDVA), sphere, K2, K-average, K-max and Q-anterior (p = 0.02, 0.01, 0.002, 0.001, 0.0001 and 0.03, respectively) compared to that of group A. However, group A exhibited better refractive cylindrical improvements (p = 0.04). In group A, we documented spontaneous extrusion of one Keraring segment. CONCLUSION: Single 210° arc-length segment implantation using our objective QN was more efficacious for keratoconus treatment than using the subjective SN. The nomograms were comparable when the Q-anterior value was >-1.00; however, the QN was superior to the SN when the Q-anterior value was ≤-1.00. The QN yielded greater postoperative UDVA and smoother corneal remodelling than did the SN for treatment of grade 1 and 2 keratoconic eyes.

Long-Term Refractive Outcome of Small Incision Lenticule Extraction in Very High Myopia.

PURPOSE: To assess the stability, safety, predictability, and efficacy of small incision lenticule extraction (SMILE) in high myopia. METHODS: The study was conducted as a retrospective noncomparative analysis of the records of 495 eyes of 270 patients treated by the ReLEx SMILE technique for a mean spherical myopic error of -12.84 ± 2.47 D (range: -10.0 to -14.0 D) combined with a mean astigmatism of -1.17 ± 1.34 D (up to -4.0 D). The mean LogMAR corrected distance visual acuity (CDVA) was 0.2 ± 0.6. In this study, 225 patients had the bilateral SMILE procedure, whereas 45 patients had a single eye treated with SMILE. RESULTS: One month after surgery, the mean refractive error was 20.72 ± 0.88 D (range: +1 to 21.5 D), and the mean postoperative astigmatism was -0.83 ± 1.04 D. The mean LogMAR UDVA was 0.2 ± 0.34. In the last follow-up visit, 3 years after surgery, all the before mentioned parameters were the same or within minimal changes with no statistically significant difference from the earlier results. However, the spherical error demonstrated a significant change from -0.72 ± 0.88 D at 1 month to -1.17 ± 1.01 D at the end of the follow-up. However, this change had an insignificant visual impact. At the end of the follow-up period, approximately 94% of patients had unchanged CDVA or gained one or more lines, 6% lost one line of CDVA, and 1% lost 2 lines. CONCLUSIONS: SMILE may be effective and safe, with a stable and predictable outcome for correction of very high myopia.

Comparison between refractive outcomes of femtosecond laser-assisted cataract surgery and standard phacoemulsification.

BACKGROUND: To compare the visual and refractive outcomes of femtosecond laser assisted cataract surgery (FLACS) using Victus platform (Technolas Bausch and Lomb (B&L), Munich, Germany) and conventional phacoemulsification cataract surgery (CPCS). METHODS: A retrospective study of 100 eyes operated for cataract. FLACS was performed in 50 eyes and CPCS was done in another 50 eyes. Preoperative and 6 months postoperative visual and refractive evaluation (efficacy, safety, predictability, and surgically induced astigmatism) as well as higher-order aberrations were analyzed. Efficacy index which equals post-operative mean of uncorrected distance visual acuity (UDVA) divided by preoperative mean corrected distance visual acuity (CDVA) was calculated in both groups. Safety index equals post-operative mean of corrected distance visual acuity (CDVA) divided by preoperative mean CDVA. RESULTS: Logarithm of the Minimum Angle of Resolution (LogMAR), UDVA improved in both groups after surgery (p < 0.05). It was 0.23 ± 0.20 and 0.291 ± 0.311 log MAR in FLACS and CPCS groups respectively. Safety index was 1.777 in FLACS group and 1.744 in CPCS groups showing high degree of safety of both measures. Mean surgically induced astigmatism (SIA) was 0.35 ± 0.67 D and 0.901 ± 0.882 D in FLACS and CPCS groups respectively (p = 0.015). The post-operative comparison between both groups was in favor of CPCS group vs. FLACS group regarding total aberrations (0.563 ± 0.386 vs. 0.91 ± 1.20) (p = 0.03), while low order aberrations were significantly less in FLACS group vs. CPCS group (0.64 + 0.63 vs. 2.07 + 3.15) (p = 0.027). RMS high order aberration was higher in FLACS group vs. CPCS group but of no statistical significance 0.54 ± 0.96 vs. 0.328 ± 0.360 (p = 0.082). CONCLUSION: Femtosecond laser -assisted cataract surgery was a safe and precise procedure but enhanced visual outcomes only minimally when compared to conventional cataract surgery in experienced hands. Both FLACS and manual surgeries can achieve a high efficacy, predictability and safety with slight superior outcomes in FLACS. TRIAL REGISTRATION NUMBER: PACTR201804003256258 (date: 27 Mar 2018) Available at: https://pactr.samrc.ac.za/.

Standard cross-linking protocol versus accelerated and transepithelial cross-linking protocols for treatment of paediatric keratoconus: a 2-year comparative study.

PURPOSE: To compare the efficacy, safety and stability of standard epithelium-off cross-linking (SCXL) versus accelerated epithelium-off cross-linking (ACXL) and transepithelial epithelium-on cross-linking (TCXL) in the treatment of progressive keratoconus (KC) in children. METHODS: This prospective multicentre controlled trial included 271 eyes (136 children) with grade 1-3 progressive KC who were randomized to undergo SCXL (n = 91, as a control group), ACXL (n = 92) or TCXL (n = 88). Uncorrected and corrected distance visual acuity, subjective refraction, pachymetry, keratometry and corneal topography measurements were recorded preoperatively and 6, 12 and 24 months postoperatively. RESULTS: At 1 year, there was no significant difference in uncorrected distance visual acuity, refractive sphere, cylinder, spherical equivalent or Kmax between the ACXL and SCXL groups; however, during year 2, ACXL regressed while SCXL continued to improve. After 2 years, there were significant differences in all visual, refractive and keratometric components between SCXL and both ACXL and TCXL (p < 0.0001) and between ACXL and TCXL (p < 0.0001). KC progressed in 5.4% of patients who had ACXL and 28.4% of those who had TCXL but in none of those who had SCXL. Vernal keratoconjunctivitis was documented in 43.3% of eyes that progressed postoperatively. CONCLUSION: SCXL was more effective for paediatric KC and achieved greater stability than either ACXL or TCXL, and ACXL was superior to TCXL. SCXL also achieved marked improvement in both myopia and spherical equivalent; however, these refractive outcomes were unpredictable and uncontrollable. TCXL had a 28.4% failure rate within 2 years. SCXL is preferable for management of paediatric KC.

Visual and Refractive Long-Term Outcomes Following Standard Cross-Linking in Progressive Keratoconus Management.

PURPOSE: To analyze the effectiveness and stability of the refractive, topographic and visual outcomes of the standard cross-linking (SCXL) in keratoconus (KC) management. PATIENTS AND METHODS: This study was designed as a retrospective non-comparative study that included 28 KC patients (n=49 eyes) who performed SCXL as a single procedure to treat KC and completed five-year follow-up period. The topographic, refractive and visual data were recorded preoperatively and at 12, 24, 36 and 60 months postoperatively. RESULTS: Forty eyes (81.6%) showed achieved postoperative spherical equivalent (SE) refraction better than the attempted refraction. Ten eyes (20.4%) improved by <1 D, 23 eyes (46.9%) improved from 1 D to <2 D and 7 eyes (14.3%) improved by ≥2 D. Both uncorrected distant visual acuity (UDVA) and corrected distant visual acuity (CDVA) showed statistically significant improvement from preoperative 1.34±0.29 (mean±SD) and 0.74±0.23 LogMAR to postoperative 0.99±0.32 and 0.50±0.22 LogMAR (P<0.0001) respectively. Both Kmax and SE refraction showed statistically significant and stable improvement from preoperative 51.95±1.90 and -7.90±3.14 D to postoperative 50.19±1.96 and -6.35±2.49 D (P<0.0001) respectively. Two eyes (4%) showed KC progression at the end of 5th follow-up year. CONCLUSION: SCXL had good effectiveness and stability that halted KC progression over 5-year follow-up period. It had also unexpected improvement in the KC refractive components mainly the spherical and SE components.

Analysis of the Outcomes of Combined Cross-Linking with Intracorneal Ring Segment Implantation for the Treatment of Pediatric Keratoconus.

PURPOSE: To analyze the visual and refractive outcomes of combined accelerated cross-linking with femtosecond laser intracorneal ring segment implantation for the treatment of pediatric keratoconus. MATERIALS AND METHODS: This retrospective multicenter noncomparative clinical study included 63 eyes of 37 patients (age, 9-17 years) who underwent between August and September 2016 combined cross-linking with intracorneal ring segment implantation for keratoconus. Preoperative and postoperative (6, 12, and 18 months) uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), subjective refractions, keratometry (K), and pachymetry measurements were compared. RESULTS: The postoperative spherical equivalent refraction was within ±1 D, ±2 D, and ±3 D in 19 (30.2%), 27 (42.9%), and 37 (58.8%) eyes, respectively. Only 27 eyes achieved the attempted preoperative spherical equivalent refraction. The mean spherical equivalent refraction significantly improved from -6.01 ± 2.97 to -3.13 ± 2.78 D postoperatively (P < 0.0001). The mean K average reading significantly decreased from 48.75 ± 4.25 to 46.65 ± 3.89 D postoperatively (P < 0.0001). The mean postoperative myopic, astigmatic, and spherical equivalent corrections were -2.17 ± 2.19, -1.52 ± 2.03, and -2.93 ± 2.35 D, respectively. The mean UDVA and CDVA showed significant improvements (0.89 ± 0.33 to 0.40 ± 0.28, P < 0.0001; 0.35 ± 0.31 to 0.25 ± 0.24, P = 0.004; respectively) at 18 months postoperatively. Keratoconus progression, segment migration, and segment extrusion were seen in four (6.4%), one (1.6%), and three (4.7%) eyes, respectively, probably contributing to the lower mean postoperative CDVA. CONCLUSION: Cross-linking plus is only partially effective for pediatric keratoconus. Despite some improvements in vision and keratometry measures, it resulted in complications such as keratoconus progression, segment extrusion, and segment migration that affected the vision in some patients. These findings suggest an assessment of standard epithelium-off collagen cross-linking as a sole procedure to treat pediatric keratoconus in future studies.

Standard cross-linking versus photorefractive keratectomy combined with accelerated cross-linking for keratoconus management: a comparative study.

PURPOSE: To compare the safety and efficacy of standard 30 min epithelium-off cross-linking (CXL) versus photorefractive keratectomy (PRK) combined with accelerated epithelium-off cross-linking (AXL) for the treatment of progressive keratoconus (CXL-Plus). METHODS: This study was a prospective multicentre comparative clinical study. A total of 125 eyes of 75 patients with grade 1 keratoconus and documented progression were divided into two groups. Group A included 58 eyes treated with standard CXL. Group B included 67 eyes treated with combined PRK and AXL. The recorded data included UDVA, CDVA, subjective and objective refraction, keratometry and pachymetry using corneal topographies preoperatively and postoperatively at 3, 6, 12 and 24 months of follow-up. RESULTS: In group A, at 24 months of UDVA and CDVA were improved from 1.12 ± 0.38 and 0.58 ± 0.42 to 0.66 ± 0.20 and 0.20 ± 0.12 (LogMAR±SD). The spherical equivalent was reduced from 4.03 ± 1.18 to 1.78 ± 1.04 D. The cylinder reduction was 0.32 ± 0.19 D. In group B, at 24 months of UDVA and CDVA were improved from 1.26 ± 0.52 and 0.68 ± 0.36 to 0.58 ± 0.28 and 0.20 ± 0.16 (LogMAR ± SD). The spherical equivalent was reduced from 4.23 ± 0.95 to 1.92 ± 0.74 D. The cylinder reduction was ±1.76 D. CONCLUSION: Surprisingly, standard CXL showed close results to CXL-Plus at the 24th follow-up month. Standard CXL acted as a stabilizing procedure associated with a late myopic component reduction. CXL-Plus acted as a refractive and stabilizing procedure with an early effect on both the myopic and the astigmatic component but no later improvements. Standard CXL seems to be more powerful than AXL in its long-term effect. Therefore, in the future, we want to test the combination of PRK with standard CXL.

Evaluation of the Effectiveness of Cross-Linking Combined With Photorefractive Keratectomy for Treatment of Keratoconus.

PURPOSE: To evaluate the effectiveness and safety of combined epithelium-off cross-linking (CXL) with photorefractive keratectomy (CXL Plus) for correction of the myopic and astigmatic components of keratoconus. METHODS: Seventy-nine eyes of 46 patients who underwent CXL Plus were enrolled in this retrospective, multicenter, noncomparative clinical study. Uncorrected distance visual acuity, corrected distance visual acuity, refraction, keratometry, and pachymetry measurements were recorded preoperatively and at 3, 6, 12, and 18 months during follow-up. RESULTS: The mean (±SD) preoperative uncorrected distance visual acuity and corrected distance visual acuity were 1.00 ± 0.22 logarithm of the minimum angle of resolution (logMAR) and 0.62 ± 0.38 logMAR, respectively, and improved to 0.71 ± 0.36 logMAR and 0.32 ± 0.18 logMAR postoperatively. The mean k value, mean corneal thickness at the thinnest location, and mean myopic and astigmatic components decreased from 46.58 ± 0.97 D, 473 ± 29 µm, 3.65 ± 1.72 D, and 1.83 ± 0.69 D preoperatively to 43.79 ± 1.17 D, 431 ± 38 µm, 1.02 ± 0.78 D, and 1.15 ± 0.26 D, respectively, during follow-up. Eleven eyes had delayed epithelial healing, 2 had stromal opacities, 1 had primary herpes simplex keratitis, and 5 showed progression of keratoconus. CONCLUSIONS: CXL Plus improved the refractive status of keratoconus during 18 months of follow-up, despite its potential early postoperative complications of delayed epithelial healing and corneal haze. CXL Plus reduced the myopic component more than the astigmatic component of keratoconus. However, the safety and stability of the procedure were offset by longer-term postoperative complications and a high rate of postoperative progression of keratoconus.

Combined femtosecond laser-assisted intracorneal ring segment implantation and corneal collagen cross-linking for correction of keratoconus.

PURPOSE: To assess the safety, predictability, and effectiveness of Keraring intrastromal corneal ring segments (ICRS) insertion assisted by femtosecond laser and corneal collagen cross-linking (CXL) for keratoconus correction. PATIENTS AND METHODS: In this prospective, noncomparative, and interventional case series, 160 eyes of 100 adult keratoconus patients with poor best-corrected visual acuity (BCVA) (less than 0.7) and intolerance to contact lens wear were included. Patients underwent femtosecond laser-assisted placement of ICRS and CXL. All patients were examined for a complete ophthalmological test: uncorrected visual acuity (UCVA), BCVA, spherical equivalent, keratometry (K1-flat and K2-steep), pachymetry, and Scheimpflug imaging with the Pentacam at 1 week and at 1, 3, and 6 months postoperatively. RESULTS: At 6 months, a significant difference was observed (P<0.001) in mean UCVA and BCVA from 0.92±0.677 and 0.42±0.600 logMAR preoperatively to 0.20±0.568 and 0.119±0.619 logMAR, respectively. Mean spherical equivalent refractions were significantly lower (P<0.001) at 6 months. Mean keratometry (K) also significantly reduced (P<0.001) from 50.93±5.53 D (K1-flat) and 55.37±5.76 D (K2-steep) to 47.32±4.61 and 51.08±5.38 D, respectively. In terms of pachymetry, no significant difference was observed preoperatively versus postoperatively (P=1.000). CONCLUSION: Keraring ICRS insertion assisted by femtosecond laser and corneal CXL provided significant improvement in visual acuity, spherical equivalent, and keratometry, which suggests that it may be effective, safe, and predictable for keratoconus correction.