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.

Inflammatory profile of keratoconic corneal epithelium.

BACKGROUND: Recent studies have presented inflammatory features on keratoconus (KC) and many inflammatory markers are described in the tears of patients with this disease. The KC pathogenesis is still unknown just like the correlation with inflammatory patterns. However, environmental and genetic issues may be part of the progress of KC. In addition, some systemic features, such as allergy and obesity, seem to be related to the progression of KC. Our purpose was to evaluate the neuropeptides vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), chemokines ligand 2 (CCL-2) and 5 (CCL-5), and interleukins 6 (IL-6) and 8 (IL-8) on corneal epithelial cells and blood of patients with KC and in healthy controls. In addition, the neutrophil-to-lymphocyte ratio (NLR) was evaluated to predict inflammation. METHODS: This including prospective observational study included 32 KC patients who underwent corneal crosslinking (CXL) and 32 control patients who underwent photorefractive keratectomy (PRK). Patients' corneal epithelial cells were removed surgically, and blood (buffy coat) was analyzed. Samples in triplicate were evaluated on rt-PCR for neuropeptides (VIP e NPY), interleukins (IL-6 e IL-8), and chemokines (CCL-2 and CCL-5). RESULTS: Our study showed statistically higher CCL-5 and IL-8 on corneal epithelial cells in patients with KC. Blood cells were statistically higher in VIP and NPY in the KC group. Interleukin-8 on blood cells was statistically significant in KC'S group; for CCL-2 and CCL-5 they were statistically lower in patients with KC compared with controls. NLR showed no difference between the groups. CONCLUSIONS: Our data support the findings of other studies that suggested altering KC status, such as inflammatory corneal disease. The presence of IL-8 in the cornea and blood samples of KC's group suggested systemic disease with a possible local or repercussion action. Further studies are warranted to elucidate KC pathogenesis and its correlation to systemic disease.

Vision-Related Quality of Life in Patients With Keratoconus With Enantiomorphic Topography After Bilateral Intrastromal Corneal Ring Implantation.

PURPOSE: The aim of this study was to evaluate the quality of life (QOL) after intrastromal ring implantation in patients with keratoconus. METHODS: This was a prospective, randomized, interventional study. We analyzed 60 eyes of 30 patients aged 16 to 35 years who were treated at the Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, Brazil. The Visual Function Questionnaire (VFQ-25) and Short-Form 36 Questionnaire (SF-36) were used before intracorneal ring segment (ICRS) implantation and at 3, 6, and 12 months after surgical intervention. RESULTS: The mean corrected visual acuity improved from a mean of 0.32 ± 0.2 logMAR (20/40) preoperatively to 0.14 ± 0.11 logMAR (20/25) 1 year postoperatively ( P = 0.001). The mean spherical equivalent varied from -7.24 ± 3.47 preoperatively to -4.13 ± 2.41 postoperatively ( P = 0.001). The overall composite score for the VFQ-25 improved from 55.1 preoperatively to 80.4 1 postoperatively ( P = 0.001). SF-36 showed statistically significant improvement in all scores. When analyzing the correlation between visual acuity and VFQ composite score, a significant correlation was found between both variables (Pearson correlation coefficient of -0.40, P = 0.001). CONCLUSIONS: Patients with keratoconus had increased psychological symptoms and lower QOL and improved psychosocial criteria associated with corneal remodeling and decreased visual dependence on others after surgery. Extrapolation of these data to the whole keratoconus population suggests that ICRS implantation could improve QOL in these patients.

Comparison of visual outcomes of bilateral dual-technology diffractive intraocular lens vs blended enhanced monofocal with dual-technology intraocular lens.

PURPOSE: To compare clinical outcomes after implantation of TECNIS Synergy (ZFR00V) intraocular lenses (IOLs) in both eyes and implantation of the TECNIS Synergy and TECNIS Eyhance (ICB00) combination in patients undergoing cataract surgery. SETTING: Department of Cataract, Hospital Oftalmológico de Brasilia (HOB), Brasília, Brazil. DESIGN: Prospective, interventional, randomized, parallel-group study. METHODS: Patients were categorized into 2 groups: Group 1: ZFR00V IOL was implanted in both eyes. Group 2: An ICB00 IOL was implanted in the dominant eye, and a ZFR00V IOL was implanted in the nondominant eye. RESULTS: Visual acuity was similar between the 2 groups (95% CI <0.1 logMAR). A superior visual acuity of ≥ 20/25 (at -2.00 to -2.50 diopters [D]) was achieved in Group 1 (bilateral ZFR00V) than in Group 2 (combination of ZFR00V/ICB00). The binocular defocus curve demonstrated better visual acuity at 40 cm (-2.00 D) and 50 cm (-2.50 D) in Group 1 than in Group 2 ( P < .05). Similar contrast sensitivity values were observed between the 2 groups. Patients in Group 1 reported higher satisfaction (completely satisfied) than those in Group 2 ( P < .05). However, halos and glare were more pronounced in Group 1 than in Group 2 ( P < .05). CONCLUSIONS: Both presbyopia-correcting IOL combinations showed similar binocular visual acuity results. Group 1 demonstrated enhanced visual acuity in the defocus curve at 40 cm (-2.00 D) and 50 cm (-2.50 D). Comparable contrast sensitivity outcomes were observed in both groups. Patients were more completely satisfied in Group 1 than in Group 2, despite the higher frequency of postoperative nighttime halos and glare.

Astigmatism Profile in a Large Series of Brazilian Patients.

PURPOSE: To assess anterior, posterior, and total corneal astigmatism in a large sample of Brazilian patients. METHODS: In this retrospective cross-sectional study, all patients whose corneas were imaged with the Galilei G6 (Ziemer Ophthalmology) between January 2017 and February 2019 at HOPE Eye Hospital, in Recife, Brazil, were eligible to participate. Anterior, posterior, and total corneal astigmatism values were collected and analyzed. RESULTS: The study included 3,253 eyes of 1,919 patients. The mean magnitude of the anterior, posterior, and total corneal astigmatism was 1.50 ± 1.11, 0.34 ± 0.15, and 1.29 ± 0.98 diopters (D), respectively. Corneal astigmatism was greater than 0.50 D in the anterior cornea of 86.3% of eyes (2,807 eyes) and in the posterior cornea of 13.2% of eyes (429 eyes). Vertical alignment of the steepest corneal meridian was observed in the anterior cornea of 74.5% of eyes (2,423 eyes) and in the posterior cornea of 93.1% of eyes (3,029 eyes). The correlation between the astigmatism magnitude of the anterior and posterior cornea was strong when the steep anterior meridian was aligned vertically (r = 0.720; P < .001), and absent when it was aligned horizontally (r = 0.102; P = .036). CONCLUSIONS: Corneal astigmatism values in the Brazilian population were similar to those found in other ethnicities, suggesting that toric calculators, nomograms, coefficients of adjustment, and formulas that were developed based on astigmatism values of other populations may be used in Brazilian patients with comparable accuracy. [J Refract Surg. 2023;39(1):56-60.].

Spectrophotometric Analysis of Different Polymethyl Methacrylate Filters and their Importance in the Implantation of Corneal Rings.

PURPOSE: This study evaluated the luminous behavior applied to materials used in intraocular surgeries. METHODS: Discs of the different products were delivered in 19.00 mm × 3.00 mm. Each sample was fixed on support keeping it perpendicular to the spectrophotometer beam. Later, their analyses were carried out in the air/PMMA ratio. The graphs of individual profiles of the measurements along the length were constructed according to each of the filters from the spectrophotometric analysis. In addition, descriptive statistics of transmittance and absorbance for each wavelength presented were correlated for each filter. RESULTS: It is possible to observe that the minimum absorption measure was found in the Red Filter, especially in the blue and green light spectrum. CONCLUSION: Using filters in PMMA materials appears to improve visual quality in corneal implants, especially the red filter, due to greater absorbance of light leading to fewer light scattering phenomena through corneal rings. However, further studies comparing the effects of different filters on Intracorneal rings should be carried out to elucidate this field of study.

Measurement of the visual axis through two different methods: quantification and differences for measuring chord µ.

PURPOSE: To compare the differences between the apparent and actual chord µ. METHODS: In this prospective, comparative, non-randomized, and non-interventional study, imaging examinations using Pentacam and the HD Analyzer were performed in the same room under the same scotopic conditions. The inclusion criteria were patients aged 21-71 years, able to provide informed consent, myopia up to 4D, and anterior topographic astigmatism up to 1D. Patients using contact lenses, those with previous eye diseases or surgeries, corneal opacities, corneal tomographic changes, or suspected keratoconus were excluded. RESULTS: Altogether, 116 eyes of 58 patients were analyzed. The patients' mean age was 30.69 (±7.85) years. In the correlation analyses, Pearson's correlation coefficient of 0.647 indicates a moderate positive linear relationship between apparent and actual chord µ. The mean actual and apparent chord µ were 226.21 ± 128.53 and 278.66 ± 123.90 µm, respectively, with a mean difference of 52.45 µm (p=0.01). The analysis of mean pupillary diameter resulted in 5.76 mm using the HD Analyzer and 3.31 mm using the Pentacam. CONCLUSIONS: We found a correlation between the two measurement devices, and even though we found considerable differences, both can be used in daily practice. Given their differences, we should respect their peculiarities as well.

Corneal Higher Order Aberrations and Epithelial Remodeling With Femtosecond Laser-Assisted LASIK Topography-guided and Customized Asphericity Ablation in the Contralateral Eye: A Randomized, Double-Blind, Prospective Study.

PURPOSE: To evaluate refractive results, corneal higher order aberrations (HOAs), and epithelial remodeling in the preoperative and postoperative period of regular corneas that had topography-guided femtosecond laser-assisted laser in situ keratomileusis (LASIK) (Contoura WaveLight; Alcon Laboratories, Inc) and compare them with the contralateral eye that underwent ablation customized by asphericity (Custom-Q WaveLight; Alcon Laboratories, Inc) in myopic eyes with or without astigmatism. METHODS: A prospective, randomized, and double-blind study was conducted. Patients underwent preoperative and postoperative epithelial mapping and corneal tomography to assess the epithelial thickness map, HOAs of the corneal anterior surface, visual acuity, and refractive evaluation. RESULTS: This study enrolled 96 normal eyes of 48 patients. Uncorrected distance visual acuity of 20/20 or better was achieved in 97% of patients and gains in corrected distance visual acuity and effectiveness in correcting refractive astigmatism were similar in both techniques. Seventeen sectors of the corneal epithelium map were assessed by spectral-domain optical coherence tomography and no significant differences were found between techniques preoperatively and postoperatively (P > .05). HOA root mean square, coma Z3±1, trefoil Z3-3, and tissue consumption exhibited statistically significant between-technique differences (P < .05). CONCLUSIONS: The Contoura and Custom-Q techniques were similar with respect to refractive and visual outcomes after 3 months, as well as in epithelial remodeling. The Contoura provides lower postoperative HOA root mean square, coma Z3±1, and trefoil Z3-3 values, but the techniques showed no differences in the correction of the corneal astigmatic wavefront component and in the spherical aberration after 3 months. [J Refract Surg. 2023;39(11):751-758.].

KeraKlear Artificial Cornea Implantation Assisted by Femtosecond Laser in Eyes With Aniridia.

PURPOSE: The purpose of this study was to evaluate the feasibility of treating aniridia-associated keratopathy with a nonpenetrating artificial cornea in 2 patients with corneal blindness secondary to aniridia. METHODS: This was a prospective, nonrandomized, interventional study of 2 consecutive patients with corneal blindness caused by aniridia. Ophthalmological examination was performed before the nonpenetrating keratoprosthesis surgery and then repeated 1, 7, 15, 30, 90, and 180 days and subsequently every 90 days thereafter. Optical coherence tomography was performed 90 days postsurgery to assess the position of the implant. RESULTS: Visual acuity improved significantly after the KeraKlear surgery. Postoperative findings included periprosthetic corneal thinning, neovascularization, and retroprosthetic opacity. CONCLUSIONS: KeraKlear nonpenetrating artificial corneas represent a promising alternative to keratolimbal allografts and Boston keratoprosthesis for the treatment of aniridia-associated keratopathy.

Toric intraocular lens misalignment inducing astigmatism after refractive surgery.

PURPOSE: To report the unexpected induction of astigmatism after phacoemulsification and toric intraocular lens (IOL) implantation in an eye with previous corneal refractive surgery. METHODS: Case report of a 46-year-old man with bilateral nuclear cataract and previous photorefractive keratectomy. Because corneal topography identified regular corneal astigmatism at the central optical zone, phacoemulsification and implantation of a one-piece hydrophobic acrylic toric IOL were performed. RESULTS: Unexpected induction of astigmatism occurred in the first operated eye despite proper alignment of the IOL according to the preoperative calculations using simulated K values to determine toric IOL power and alignment. A retrospective qualitative analysis of corneal topography showed mismatching of the steepest meridian, leading to an off-axis IOL. Secondary IOL rotation improved both uncorrected and corrected distance visual acuity. CONCLUSIONS: Qualitative analysis of the corneal topography is mandatory during the assessment of toric IOL alignment in eyes with previous corneal refractive surgery to identify the actual location of the steepest meridian.

Ocular response analyzer measurements in keratoconus with normal central corneal thickness compared with matched normal control eyes.

PURPOSE: To compare corneal hysteresis (CH) and corneal resistance factor (CRF) in eyes with keratoconus with a central corneal thickness (CCT) ≥ 520 µm with CH and CRF in matched controls, and to estimate the sensitivity and specificity of these parameters for discriminating between the two groups. METHODS: This prospective, comparative case series comprised 19 eyes of 19 patients with keratoconus with CCT ≥ 520 µm and 19 eyes of 19 healthy sex-, age-, and CCT-matched patients who underwent a complete clinical eye examination, corneal topography, tomography, and biomechanical evaluation. The receiver operating characteristic (ROC) curve was used to identify cutoff points that maximized the sensitivity and specificity for discriminating between groups. RESULTS: Central corneal thickness was 543.1 ± 13.9 µm (range: 520 to 568 µm) in the keratoconus group and 545 ± 12.5 µm (range: 527 to 575 µm) in the control group (P=.6017). Corneal hysteresis was 9.22 ± 1.44 mmHg (range: 6.2 to 11.35 mmHg) in the keratoconus group and 10.58 ± 1.91 mmHg (range: 7.34 to 13.53 mmHg) in the control group (P=.0075). Corneal resistance factor was 8.62 ± 1.52 mmHg (range: 5.60 to 11.20 mmHg) in the keratoconus group and 10.30 ± 1.92 mmHg (range: 6.95 to 14.12 mmHg) in the control group (P=.0049). The ROC curve analyses showed a poor overall predictive accuracy of CH (cutoff, 9.90 mmHg; sensitivity, 78.9%; specificity, 63.2%; test accuracy, 71.05%) and CRF (cutoff, 8.90 mmHg; sensitivity, 68.4%; specificity, 78.9%; test accuracy, 73.65%) for detecting keratoconus in the eyes studied. CONCLUSIONS: Corneal hysteresis and CRF were statistically lower in the keratoconus group compared with the control group. Given the large overlap, both CH and CRF had low sensitivity and specificity for discriminating between groups.

Comparison of optical aberrations and contrast sensitivity between aspheric and spherical intraocular lenses.

PURPOSE: To compare visual acuity, aberrometry, and contrast sensitivity in patients who had a spherical intraocular lens (IOL) (SoFlex SE, Bausch & Lomb) implanted in one eye and an aspheric IOL (SofPort AO, Bausch & Lomb) implanted in the fellow eye during uncomplicated cataract surgery. METHODS: A prospective, multicenter, double-blind study was performed. Forty patients (80 eyes) underwent bilateral phacoemulsification with implantation of a spherical IOL in one eye and an aspheric IOL in the fellow eye. Postoperatively, visual acuity, aberrometry, and contrast sensitivity tests were performed. Statistical analyses were performed using Student t and Wilcoxon tests, and mixed effects were used for each contrast condition situation. RESULTS: Thirty-nine patients (30 women, 9 men; 78 eyes) with a mean age of 69.3±6.17 years (range: 51 to 82 years) completed the study. No statistical differences were found regarding visual acuity among eyes. Lower levels of higher order aberrations were achieved in the aspheric group. No statistical difference between groups under photopic conditions was noted. In low spatial frequencies, better performance was observed with the aspheric IOL under mesopic conditions. In high spatial frequencies, the spherical IOL produced better quality of vision. Comparing mesopic conditions with glare, visual performance was statistically better using the aspheric IOL. CONCLUSIONS: Cataract surgery results cannot be measured by means of visual acuity alone. Quality of vision must be considered, and implantation of IOLs with low levels of spherical aberrations and better contrast sensitivity are preferred. In this study, the aspheric IOL demonstrated better visual function, especially at night, when compared with spherical IOLs.

Association between keratoconus, ocular allergy, and sleeping behavior.

PURPOSE: To compare the severity and laterality of keratoconus according to allergic rhinitis, scratching and sleeping habits, and manual dexterity. METHODS: Objective assessments regarding allergic rhinitis, eye itching, and slee-ping position among patients with keratoconus (diagnosed based on corneal tomography) were conducted. Diagnostic criteria and classification were based on the Amsler-Krumeich classification. RESULTS: Ocular pruritus was reported by 29 of 34 participants (85.29%). Eighteen participants (62.07%) reported equal scratching of both eyes, six (20.69%) more on the right eye, and five (17.24%) more on the left eye. Comparison of the main sleeping position and the eye with more severe presentation of the disease using Fisher's exact test revealed some correlations (0.567 and 0.568 in the right and left eye, respectively). However, these correlations were not statistically significant. CONCLUSIONS: The association between higher keratometry values and sleeping position appears to be more significant than that reported between keratometry and itching, or manual dexterity.

Outcomes of iris-claw anterior chamber versus iris-fixated foldable intraocular lens in subluxated lens secondary to Marfan syndrome.

PURPOSE: To compare the outcome of phacoemulsification using 2 different iris-fixation techniques for intraocular lens (IOL) replacement, a foldable posterior chamber IOL (PCIOL; AcrySof MA60AC, Alcon Laboratories Inc, Fort Worth, TX) and an iris-claw anterior chamber IOL (ACIOL; Artisan, Ophtec BV), for treatment of subluxated lenses in patients with Marfan syndrome (MFS). DESIGN: Randomized, controlled trial. PARTICIPANTS: A total of 31 eyes of 16 patients with subluxated lenses associated with MFS and a preoperative corrected visual acuity (CVA) < or =20/40 based on the Early Treatment Diabetic Retinopathy Study chart. METHODS: Patients were enrolled and the eye with worse visual acuity was randomly assigned to 1 of 2 study arms: phacoemulsification and iris-fixated PCIOL or phacoemulsification and iris-claw ACIOL; the second eye of the same patient received the other IOL type. Preoperative and postoperative ophthalmologic examination, optical coherence tomography, and endothelial cell counts were performed. MAIN OUTCOME MEASURES: We recorded CVA results at 3, 6, and 12 months, complications, endothelial cell loss, and central retinal thickness. RESULTS: In the iris-fixated PCIOL group, CVA was significantly improved at 3 (P = 0.011; n = 16), 6 (P = 0.006; n = 16), and 12 months (P = 0.002; n = 16). In the iris-claw ACIOL group, CVA was significantly improved at 3 (P = 0.001; n=15), 6 (P = 0.001; n = 15), and 12 months (P = 0.009; n = 12). The CVA results did not differ significantly between groups. Dislocation of the IOL occurred in 3 of 16 (18.75%) eyes in the PCIOL group. Retinal detachment occurred in 3 eyes (2 in the PCIOL group and 1 in the ACIOL group) and was successfully repaired. Postoperative foveal tomograms in both groups revealed a decrease in the mean foveal thickness (MFT; < or =172 microm) in 54.16% of the patients. CONCLUSIONS: The iris-sutured PCIOL and iris-claw ACIOL produced comparable improvements in CVA at 3, 6, and 12 months postoperatively. Although IOL dislocation tended to occur more frequently in the iris-fixated PCIOL group, the difference was not significant. At 6 months postoperatively, all study patients tended to have a thinner MFT. None of the patients in either group developed cystoid macular edema.

Corneal biomechanical metrics and anterior segment parameters in mild keratoconus.

PURPOSE: To compare corneal hysteresis (CH), corneal resistance factor (CRF), spherical equivalent (SE), average central keratometry (K-Avg), corneal astigmatism (CA), corneal volume (CV), anterior chamber (AC) depth, and central corneal thickness (CCT) between patients with mild keratoconus and healthy controls and to estimate the sensitivity and specificity of CH and CRF in discriminating mild keratoconus from healthy corneas. DESIGN: Comparative case series. PARTICIPANTS: Sixty-three eyes (40 patients) with mild keratoconus (group 1) and 80 eyes from 40 gender- and age-matched controls (group 2). METHODS: Patients underwent a complete clinical eye examination, corneal topography (Humphrey ATLAS; Carl Zeiss Meditec, Dublin, CA), tomography (Pentacam; Oculus, Wetzlar, Germany), and biomechanical evaluations (ocular response analyzer; Reichert Ophthalmic Instruments, Depew, NY). The receiver operating characteristic (ROC) curve was used to identify cutoff points that maximized sensitivity and specificity in discriminating mild keratoconus from normal corneas. MAIN OUTCOME MEASURES: Corneal hysteresis, CRF, SE, K-Avg, CA, CV, AC depth, and CCT. The diagnostic performance of CH and CRF for detecting mild keratoconus was assessed using the ROC curve. RESULTS: In group 1 versus group 2, the SE values (mean+/-standard deviation) were -3.55+/-2.87 diopters (D) versus -1.46+/-3.09 D (P = 0); K-Avg, 45.09+/-2.24 versus 43.24+/-1.54 D (P = 0); CA, 3.15+/-1.87 versus 1.07+/-0.83 D (P = 0); CV, 57.3+/-2.12 versus 60.86+/-3.39 mm3 (P = 0); AC depth, 3.19+/-0.35 versus 3.05+/-0.43 mm (P = 0.0416); CCT, 503+/-34.15 versus 544.71+/-35.89 microm (P = 0); CH, 8.50+/-1.36 versus 10.17+/-1.79 mmHg (P = 0); CRF, 7.85+/-1.49 versus 10.13+/-2.0 mmHg (P = 0). The ROC curve analyses showed a poor overall predictive accuracy of CH (cutoff, 9.64 mmHg; sensitivity, 87%; specificity, 65%; test accuracy, 74.83%) and CRF (cutoff, 9.60 mmHg; sensitivity, 90.5%; specificity, 66%; test accuracy, 76.97%) for detecting mild keratoconus. CONCLUSIONS: The values for CH, CRF, CV, and CCT were statistically lower and those for SE, K-Avg, CA, and AC depth were statistically higher in patients with mild keratoconus compared with controls. Corneal hysteresis and CRF were poor parameters for discriminating between mild keratoconus and normal corneas. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Biomechanical and tomographic analysis of unilateral keratoconus.

PURPOSE: To evaluate and compare tomographic, clinical, and biomechanical data of patients with unilateral keratoconus and healthy controls. METHODS: Observational, case-control study. Complete clinical eye examination was followed by topographic (ATLAS), tomographic (Pentacam), and biomechanical (Ocular Response Analyzer) evaluation. Cases were sex- and age-matched with healthy individuals for controls. RESULTS: Four patients had unilateral keratoconus, and eight healthy patients served as controls. Central corneal thickness was 508±16 µm in the keratoconus group, 531±12.7 µm in the fellow eye group, and 528.6±40.7 µm in the control group (P>.125, all comparisons). Central keratometry was 43.70±2.70 diopters (D) in the keratoconus group, 42.84±1.43 D in the fellow eye group, and 43.81±1.94 D in the control group (P>.45, all comparisons). Corneal astigmatism was 3.30±2.24 D in the keratoconus group, 1.38±1.49 D in the fellow eye group, and 1.34±1.13 D in the control group (P=.037 between the keratoconus and control groups; P=.25 between the keratoconus and fellow eye groups). Corneal hysteresis was 8.13±2 mmHg in the keratoconus group, 8.96±0.86 mmHg in the fellow eye group, and 9.89±1.33 mmHg in the control group (P>.064, all comparisons). Corneal resistance factor was 7.96±2.43 mmHg in the keratoconus group, 8.92±1.39 mmHg in the fellow eye group, and 9.90±2.24 mmHg in the control group (P>.33, all comparisons). CONCLUSIONS: Corneal hysteresis and corneal resistance factor values were not statistically different among the groups; however, a trend for lower values was found for keratoconus and fellow eyes compared to controls. Data should be interpreted with caution because of the small sample.

Reverse order method for teaching cataract surgery to residents.

OBJECTIVE: To implement a method to train residents in the performance of phacoemulsification surgery, with the steps completed in reverse chronological order and with the easiest step being undertaken first. METHODS AND ANALYSIS: We created a method for training ophthalmology residents in which we taught phacoemulsification surgery in a series of steps learnt in reverse order. Each resident advanced through the teaching modules only after being approved in the final step and then progressed to the complete performance of surgeries. We analysed the rates of complications in the 2 years after introducing the new method. RESULTS: The new method allowed for a standardised approach that enabled replicated teaching of phacoemulsification regardless of instructor or student. After implementing the new method, residents performed 1817 phacoemulsification surgeries in the first year and 1860 in the second year, with posterior capsule rupture rates of 8.42% and 7.9%, respectively. CONCLUSIONS: Teaching residents to perform the steps of phacoemulsification in a standardised reverse order resulted in low rates of complications.

Clinical comparison of speculum's influence on intraoperative aberrometry reading.

PURPOSE: The aim of this study was to evaluate the influence of four different types of speculums on aberrometry reading (OPD SCAN III [OPD]) and on intraoperative aberrometry reading (optiwave response analyzer, ORA). PATIENTS AND METHODS: This prospective, controlled, comparative study of consecutive cases included the evaluation of five eyes of five patients with monofocal intraocular lens (IOL) implantation. Seventeen measures were performed on each patient: for each speculum, there were two measurements on the OPD and another two on ORA with four different types of blepharostats. A control measure was performed on the without blepharostat in the dominant eye of each patient, therefore totalizing 85 measurements. The measures with the blepharostats were as follows: without pressure (WF) or passive measure and after pressure (AF) or active measure to close the eye. The speculum used in all patients was as follows: open-edged wire (Barraquer); threaded with open blade (Lieberman), with 21 mm aperture; wired with solid blade (Barraquer); and threaded with solid blade (Lieberman) with 21 mm opening. An evaluation of the objective refractive data from the OPD and ORA and the corneal astigmatism from the OPD was performed. RESULTS: Spherical equivalent (SE) of the OPD with the use of blepharostat compared to the OPD without speculum presented only 37.5% of results without statistical significance. Regarding the SE of ORA with speculum usage, compared to the OPD without blepharostat, only 12.5% were not significant. Regarding the accuracy of the ORA refractive axis with the use of blepharostats, all results presented statistical significance. CONCLUSION: Thus, in the present study, we reached the conclusion between the studied blepharostats that the most suitable for use in the aphakic and pseudophakic capture of the ORA is the open blade threaded blepharostat (Lieberman).

Measurement of the visual axis through two different methods: quantification and differences for measuring chord μ / Medição do eixo visual através de dois métodos diferentes: quantificação e diferenças para medição da corda μ

ABSTRACT Purpose: To compare the differences between the apparent and actual chord μ. Methods: In this prospective, comparative, non-randomized, and non-interventional study, imaging examinations using Pentacam and the HD Analyzer were performed in the same room under the same scotopic conditions. The inclusion criteria were patients aged 21-71 years, able to provide informed consent, myopia up to 4D, and anterior topographic astigmatism up to 1D. Patients using contact lenses, those with previous eye diseases or surgeries, corneal opacities, corneal tomographic changes, or suspected keratoconus were excluded. Results: Altogether, 116 eyes of 58 patients were analyzed. The patients' mean age was 30.69 (±7.85) years. In the correlation analyses, Pearson's correlation coefficient of 0.647 indicates a moderate positive linear relationship between apparent and actual chord μ. The mean actual and apparent chord μ were 226.21 ± 128.53 and 278.66 ± 123.90 μm, respectively, with a mean difference of 52.45 μm (p=0.01). The analysis of mean pupillary diameter resulted in 5.76 mm using the HD Analyzer and 3.31 mm using the Pentacam. Conclusions: We found a correlation between the two measurement devices, and even though we found considerable differences, both can be used in daily practice. Given their differences, we should respect their peculiarities as well.

RESUMO Objetivo: Comparar as diferenças entre a chord aparente μ e o chord real μ. Métodos: Estudo prospectivo, comparativo, não randomizado e não intervencionista. Os exames de imagem (Pentacam e HD Analyzer) foram realizados na mesma sala e nas mesmas condições escotópicas. Os critérios de inclusão foram idade de 21 a 71 anos; compreensão do termo de consentimento; miopia até 4D e astigmatismo topográfico anterior até 1D. Os critérios de exclusão foram usuários de lentes de contato; pacientes com doenças oculares prévias ou cirurgias; opacidades da córnea; a presença de alterações tomográficas da córnea ou suspeita de ceratocone. Resultados: Em nosso estudo foram analisados 116 olhos de 58 pacientes. A média de idade foi de 30,69 anos (± 7,85). Análises de correlação foram desenvolvidas e o coeficiente de correlação de Pearson (0,647) indica uma relação linear positiva moderada entre as variáveis. A média do chord μ real foi 226,21 ± 128,53 μm e a média do chord μ média foi 278,66 ± 123,90 μm, com diferença média de 52,45 μm (p=0,01). A análise do diâmetro pupilar médio apresentou: 5,76mm no HD Analyzer e 3,31mm no Pentacam. Conclusões: Entendemos a existência de uma diferença significativa entre os métodos e assim a medida de ambos os dispositivos com base em princípios diferentes devemos respeitar suas peculiaridades. Como encontramos correlação entre as duas medidas, acreditamos que ambas podem ser utilizadas na prática diária.

Comparison of visual outcomes after bilateral implantation of two intraocular lenses with distinct diffractive optics.

PURPOSE: The aim of this study was to compare the visual outcomes and subjective visual quality between bilateral implantation of an extended depth of focus intraocular lens, J&J Vision Tecnis Symfony® ZXR00 (Group A) and bilateral implantation of a diffractive trifocal intraocular lens, Alcon Acrysof IQ PanOptix® TNFT00 (Group B). METHODS: This prospective, nonrandomized, comparative study of consecutive cases assessed 52 eyes of 26 patients operated on by the same surgeon (WTH) and binocularly implanted with multifocal intraocular lenses between May 2016 and July 2018. Binocular visual acuity for far, intermediate and near was tested in all cases. Ophthalmological evaluation included the measurement of binocular uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), uncorrected near visual acuity (UNVA) at 40 cm, uncorrected intermediate visual acuity (UIVA) at 70 cm, monocular visual defocus curve and the quality of life (QoL) questionnaire, National Eye Institute Visual Functioning Questionnaire - 25 ( NEI-VFQ 25). RESULTS: Postoperative UDVA was 0.00 and 0.09 logMAR (P<0.001), UIVA was 0.20 and 0.39 logMAR (P<0.001) and UNVA was 0.16 and -0.01 logMAR (P<0.001) in groups A and B, respectively; postoperative CDVA was -0.05 and 0.06 logMAR (P<0.001) in groups A and B, respectively. CONCLUSION: Both groups reported good subjective quality of vision regarding long, intermediate and short distances. Group A had a better performance for binocular UDVA, UIVA at 70 cm and CDVA, while regarding the monocular defocus curve, Group A outperformed Group B for long distances. Furthermore, Group B surpassed it in the short to very short distances, between the range of ≥2.00 D to 5.00 D of vergence. While Group A had a better performance regarding the vergences between 0.00 and 1.00 D (P<0.05) and at the vergence of +2.50 D (P=0.007). Group B outran Group A for UNVA at 40 cm.