A Treatment Approach in Congenital Fibrosis of Extraocular Muscles.

Background: Congenital fibrosis of extraocular muscles ( CFEOM) is a group of genetically defined eye-moving disorders. The syndrome is clinically characterized by congenital non-progressive ophthalmoplegia caused by dysinervation of the cranial nerves with or without ptosis. As a main sign of a CFEOM, extraocular muscles get shrunken and fibrotic, which makes surgery more technically demanding and the result more unpredictable, which makes the treatment challenging and highly customized. Our paper presents variations of the clinical picture and treatment cases of CFEOM1. Objective: To outline the importance of the clinical examination with the exact measurement of deviations for the patients with ocular fibrosis and passive duction test under general anesthesia, establishing them as the main criteria for treatment. Methods: We treated seven patients (14 eyes) with CFEOM1. The decision of the treatment was based on the measurement of the eye position in the primary position (PP), the severity of compensatory head position (CHP), restriction of motility, and passive motility test performed before surgery in general anesthesia. In 3 cases, patients were treated conservatively with the treatment of refractive error and amblyopia. However, in 4 patients, CHP and position of the eyes in PP were not acceptable, motility was severely impaired, and patients underwent surgery. The first surgery was performed on eye muscles: recession of inferior rectus muscle (IRM), anteposition, and resection of superior rectus muscle (SRM). As a second step procedure, ptosis surgery was performed. When the muscle was too tight, and it wasn't possible to have a satisfying result with conventional surgery, we used a tissue expander to improve the position and motility of the affected eyes. Results: In all operated cases, CHP has significantly improved and the position of the eyes in PP. Conclusion: Exact eye and head position measurements and a passive motility test during general anesthesia should guide the surgery. In the case when conventional surgery is not possible, implantation of a bovine pericard is a safe and effective method.

Management of Post-LASIK Ectasia.

Background: Corneal ectasia is a sight-threatening complication of corneal refractive surgery characterized by progressive steepening and thinning of the cornea and subsequent loss of best-corrected visual acuity. Objective: To report the clinical outcomes following treatment of post-laser in situ keratomileusis (LASIK) induced ectasia. Methods: This is a retrospective case series of 7 patients (10 eyes) which developed post-LASIK ectasia. In these cases of postoperative ectasia, the presented clinical signs were either forme fruste keratoconus, thin cornea, posterior elevation map value > +15.0µm, or residual stromal bed < 300µm. All cases were treated with either collagen crosslinking (CXL) alone or combined with PRK or CXL and phakic intraocular implant using the Dresden protocol and a slight modification thereof. In all cases, the flap was created using the Moria M2 mechanical microkeratome (average flap thickness 118.15±12.88µm), and refractive error was corrected using the Wavelight Allegretto excimer laser. Results: Average preoperative corrected visual acuity (CDVA) was 0.75 (±0.26) Snellen. Postoperative CDVA significantly increased to 0.86 (±0.13) Snellen (p=0.04, paired t-test). One eye lost three lines of its baseline CDVA (before ectasia), while all other eyes regained lines of CDVA. All cases remained stable during the follow-up. Conclusion: Several surgical procedures are used for the management of corneal ectasia. However, the best surgical approach should be determined based on the state of progression of the disease. Although ectasia remains a potentially devastating complication after refractive surgery, most patients can regain functional visual acuity with appropriate management, and corneal transplantation is infrequently indicated.

Stereoacuity and Multifocal Intraocular Lenses - a Systematic Review.

Background: Among various visual functions, stereoacuity, or the ability to perceive depth, is the most sophisticated binocular function. Many publications discuss the influence of retinal image formation by multifocal intraocular lenses on glare and contrast sensitivity, but only a few present results of testing binocular vision in patients with multifocal intraocular lenses. Objective: This article is designed to review the results of testing binocular vision in patients with multifocal intraocular lenses implanted in cataract surgery. Methods: This article was performed based on a literature review and Internet search through scientific databases such as PubMed, Scopus, Web of Science, and Google Scholar. Results: Some reports found that patients implanted with the monofocal lens, when measured with a near addition, presented statistically significant better stereoacuity scores than those implanted with any of the multifocal intraocular lens types. When the TNO test was used for measurement, statistically significant better stereoacuity was disclosed with the refractive multifocal intraocular lens than with the diffractive-based multifocal intraocular lens design. Stereoacuity scores, even within the same types of lenses, were significantly better with the Titmus test than with the TNO test. Conclusion: Stereoacuity is not affected by multifocality-induced retinal blur as it is by other causes of image degradation such as small residual refractive error very early opacification of ocular media or dry eye. Multifocal intraocular lenses do not cause more functional aniseikonia than would be expected with a monofocal intraocular lens. Since stereoacuity is compromised with unilateral multifocal intraocular lens implantation bilateral implantation should be attempted.

Intravitreal Sustained-release Dexamethasone Implant in Treatment for Chronic Macular Edema in Syphilis Infection: a Case Report.

Background: Macular edema results from many conditions, such as diabetic retinopathy, macular degeneration, inflammatory diseases, cataract operation, trauma, and tumors. Specifically, the capillary filtration rate should equal the speed of fluid removal from extracellular retinal tissue, such as the glial and retinal pigment epithelium cells layer (RPE). Once these forces are imbalanced, fluid accumulates in cystoid spaces within the inner layers of the retina. Objective: The main purpose of this case report is to show that macular edema caused by any inflammation, either bacteria, virus, or autoimmune origin, can be treated successfully, even if it is chronic. Case report: A 31-year-old man has been reported to our clinic with symptoms of blurry vision in the left eye, which occurred during the last year. Essential examinations included CDVA, IOP measurement, slit-lamp examination, indirect ophthalmoscopy, and OCT scan that showed significant macular edema (central foveal thickness of 353 microns). We initiated laboratory searches, such as blood, serology, and immunology testing for the next three months after his first visit, together with prescribed topical and periocular corticosteroid therapy. The test to VDRL (venereal disease research laboratory) for Syphilis and Toxocariasis came positive. We took the best decision and recommended further treatment with the intravitreal application of Dexamethasone Implant 0.7mg. One week after the intravitreal application of corticosteroids on the control exam, there were normal findings on the posterior segment with no macular edema (central foveal thickness of 269 microns). Conclusion: It is unexclusive that infection by Treponema pallidum (TP) causes isolated macular edema without any other symptoms on the anterior segment of the eye. It has indirect action on the macula, not just causing papilledema, retinal vasculitis, retinochoroiditis, and inflammatory disc edema, as expected. TP or the bacteria transmembrane protein (treponemal ligands) directly acting on vascular endothelial cells of the RPE cells, will be the key to the most certain mechanism of this condition. It is related to the possibility of the secretion of cytokines and the interactions between immune cells indirectly.

Tecnics Eyhance Iol as a Solution for Anisometropic Amblyopia Cataract Patient: a Case Report.

Background: Amblyopia affects 1-3% of the population, leading to irreversible vision loss in children and adults. Treatment options include refractive correction, occlusion therapy, and atropine penalization. Anisometropic amblyopia, caused by a difference in refractive status between the eyes, can be treated using contact lenses, glasses, ICL implantation, or cataract surgery with intraocular lens implantation. Tecnis Eyhance IOL is a superior solution, improving vision after eye surgery with a low incidence of halo, glare, or starburst. Objective: The aim is to present the case of a patient with anisometropic amblyopia, in whom Eyhance IOL was implanted in both eyes as a solution to refractive error and initial cataract due to intolerance for contact lenses. Case report: A 58-year-old female patient presented to our clinic complaining of blurry vision in her left eye that had persisted for a year. The patient reported intolerance to contact lenses and a history of amblyopia in her right eye. CDVA was 0.20 with -9.00/-1.50 x 25◦ in her right and 0.80 with +4.00 sphere correction in her left eye, while her CNVA was J9 with +2.50 and J1 with +2.50. Slit-lamp examination revealed early cataracts in both eyes, with otherwise normal findings. A dilated fundus examination showed vitreous liquefaction and myopic macula in the right eye but normal results in both eyes' posterior segments. The IOP was within normal limits, and the eye's axial length was measured. Considering the patient's intolerance to contact lenses, cataract surgery with intraocular lens implantation was deemed appropriate. Given the anisometropic amblyopia, the Eyhance lens was selected to optimize the patient's visual acuity. Following the procedure, the patient's visual acuity improved significantly, with her best CDVA at 0.35 in the right eye and 0.95 in the left eye. With +1.50 sphere correction, the CNVA was also enhanced, with the patient reading at J4 and J1 for her right and left eye, respectively. These improvements may have positively impacted the patient's quality of life and ability to perform daily activities. Conclusion: Anisometropic amblyopia in 58-year-old women was treated successfully with cataract surgery and implantation of Eyhance IOL.

Prevalence of keratoconus in refractive surgery practice population in North Macedonia.

PURPOSE: To determine the prevalence of keratoconus (KC) in relation to ethnicity in a group of people who consulted an ophthalmological care institution seeking for refractive surgery in N. Macedonia. METHODS: This was a cross-sectional, interventional retrospective study. Chart reviews were performed for all new patients attending between January 2016 and January 2020 at the Sistina Ophthalmology Hospital in Skopje. All patients were screened; KC diagnosis and classification were based on the corneal topography. Ethnicity and gender classifications were according to patients' self-opinions. RESULTS: A total of 2812 patients charts reviewed. The mean age was 31.71 years (SD ± 9.73), and 1209 (43%) were male. A total of 2050 (72.9%) declared themselves as Macedonians, 649 (23.1%) Albanians, 76 (2.7%) Turks and 37 (1.3%) in other ethnicities. Differences in age between the ethnic groups were statistically significant (x2 = 90.225, p < 0.001). KC was diagnosed in 343 patients (12.2%), while 9 (0.7%) were KC suspects and 6(0.21%) presented pellucid marginal degeneration. KC was more frequent in males (n = 246, 71.7% of total) and skewed toward younger patients. Increasing patients' age decreased the odds of KC diagnosis by 3.7% (95% CI 1.8%-4.4%) per annum. Males were four times more likely to be diagnosed with KC (AOR = 4.01; 95% CI 3.12-5.16). In comparison with Macedonian patients, Turks were more likely to be diagnosed with KC (AOR = 4.09; 95% CI 2.47-6.78). There was no difference between Macedonians and Albanians (p = 0.08). CONCLUSION: The prevalence of KC at a refractive surgery practice in N. Macedonia is much higher compared with general population (6.8/100,000) and similar to the prevalence in Middle East Asia. Nationwide screening programs are needed to diagnose the disease earlier.

A critical evaluation of longitudinal changes of astigmatism following implantation of toric implantable collamer lens (TICL): a comparison between treated and untreated cases over 4 years.

PURPOSE: To evaluate residual astigmatism following correction with toric implantable collamer lens (TICL) (group I) over a period of 4 years and compare with the change of astigmatism in spectacle wearers (group II). METHODS: Groups I (86 cases implanted with TICL [EVO + Visian ICL, Staar Surgical, Nidau, Switzeland], preop refractive error [sphere and cylinder] - 22.25 DS to - 1.00 DS and - 5.50 DC to - 1.00 DC) and II (80 cases initial refractive error [sphere and cylinder] - 18.00 DS to 0.00 DS and - 7.00 DC to - 1.00 DC) were reviewed annually. Refractive and tomography data were subjected to vector analysis to determine surgically induced astigmatism (SIA), angle of error [Δθ° = angle of target-induced astigmatism (TIA) - angle of SIA], and ΔC [TIA-SIA powers] and total corneal astigmatism (TCA) in group I and induced change in astigmatism (ICA) in group II. RESULTS: In group I, on all occasions, SIA correlated with TIA (p < 0.05); differences between SIA and TIA means were insignificant and changes in TCA were not correlated with ΔC. Mean (± sd, 95% CI) residual astigmatic powers (RA) in attending group I cases (1-4 years) were - 0.40 DC (0.58, - 0.52 to - 0.28), - 0.40 DC (0.59, - 0.52 to - 0.27), - 0.41 DC (0.58, - 0.54 to - 0.28), and - 0.61 DC (0.74, - 0.82 to - 0.40). In group II, the corresponding ICA powers were - 0.47 DC (0.53, - 0.61 to - 0.32), - 0.49 DC (0.48, - 0.69 to - 0.29), - 0.60 DC (0.40, - 0.76 to - 0.44), and - 0.86 DC (0.71, - 1.19 to - 0.52). Differences between RA and ICA were not significant. Of the group I cases presenting at 1-4 years postop, 23, 18, 16, and 28 had RA powers ≤ - 0.75 DC. Of these 12, 10, 6, and 16 were associated with Δθ° > 5° (ΔC - 0.50 to 0 DC) and 5, 1, 4, and 4 were related to ΔC (Δθ° < 5°). CONCLUSION: The development of astigmatism after TICL implantation is on par with the natural change in astigmatism in untreated cases. In about 50% of TICL cases presenting with astigmatism ≤ - 0.75 DC, the residual astigmatism could be neutralized by realigning the TICL.

Comparison between the change in total corneal astigmatism and actual change in refractive astigmatism in transepithelial photorefractive keratectomy (tPRK), laser in situ keratomileusis (LASIK) and femtosecond laser assisted laser in situ keratomileusis (FsLASIK).

PURPOSE: To compare changes in astigmatism by refraction and total corneal astigmatism after tPRK, LASIK and FsLASIK. SETTING: Specialty Eye Hospital Svjetlost, Zagreb, Croatia. DESIGN: Partially masked, semi-randomized, prospective, case-by-case, interventional, clinical study. METHODS: Patients with a stable refraction (-0.75DS to -8.00DS, astigmatism ≤1.00DC) underwent tPRK, LASIK or FsLASIK without complication. Astigmatism was measured at both corneal surfaces over the central 3.2 mm zone (approximately using Pentacam HRTM) preoperatively and 3 months postoperatively. Pentacam and refraction data were subjected to vector analysis to calculate the surgically induced changes in i) total corneal astigmatism (SIATCA) ii) any astigmatism by refraction (SIAR) and the vectorial difference (DV) between SIATCA and SIAR. RESULTS: Reporting key findings (p < .01), there was a significant difference between mean SIATCA and SIAR powers after tPRK (75eyes) but not after LASIK (100eyes) or FsLASIK (100eyes). Mean (±sd,95% CIs) values for DV powers were, tPRK -1.13DC(±0.71, -1.29 to -0.97), LASIK -0.39DC(±0.23,-0.44 to -0.34), FsLASIK -0.55DC(±0.38,-0.62 to -0.47). The differences were significant. For the tPRK and FsLASIK cases, linear regression revealed significant associations between I) SIATCA (x) &DV (z) powers (tPRK z = 1.586x-0.179, r = 0.767, p < .01; FsLASIK z = 0.442x-0.303, r = .484,p < .01), II) sines of SIATCA (x1) &DV (z1) axes (tPRK, z1 = 0.523 × 1 + 0.394, r = .650,p < .01; FsLASIK z1 = 0.460 × 1-0.308, r = .465,p < .01). CONCLUSIONS: tPRK is more prone to unintended changes in astigmatism. The difference between SIATCA & SIAR after tPRK or FsLASIK is mediated by SIATCA. Photoablating deeper regions of the cornea reduces the gap between SIATCA & SIAR.

Comparison of Flap Characteristics Created with Two Different Methods in Laser in Situ Keratomileusis (LASIK).

BACKGROUND: The creation of corneal flap is considered to be the most critical part of laser in situ keratomileusis (LASIK) surgery. Currently, flaps can be created with mechanical micorkeratomes or femtosecond lasers. OBJECTIVE: To analyze and compare flap characteristics created with two different methods for flap creation in Laser in situ keratomileusis (LASIK). METHODS: This was a retrospective study. The thickness and morphology of the flap were compared between the two mechanical microkeratomes (group I - Moria M2, group II - Moria SBK One Use Plus) and femtosecond laser (group III - Ziemer Femto LDV). Central flap thickness was measured intraoperatively, while the flap profile was measured with anterior optical coherence tomography at two axes (90° and 180°) and 5 measuring points on the first day, the first week, and one month after the surgery. RESULTS: Central flap thickness was 110.91±15.79 micrometers (µm) (80-164 µm) in group I, 98.08±13.33 µm (65-136 µm) in group II and 103.52±13.89 µm (66-138 µm) in group III. Anterior optical coherence tomography revealed a meniscus-shaped flap in all three groups at both axes (90° and 180°). The least variability in flap thickness was observed in group III (±6 µm). CONCLUSION: All three methods of flap creation provide good shape and thickness reproducibility. Ziemer Femto LDV femtosecond laser had the least variable flap thickness in a single flap. Mechanical microkeratomes had slightly lower performance.

Clinical Outcomes With a New Continuous Range of Vision Presbyopia-Correcting Intraocular Lens.

PURPOSE: To evaluate the clinical outcomes including patient-reported outcome measures in a sample of eyes undergoing bilateral cataract surgery with implantation of a new model of presbyopia-correcting intraocular lens (IOL). METHODS: This non-randomized prospective case series enrolled 206 eyes of 103 patients undergoing phacoemulsification cataract surgery with bilateral implantation of the TECNIS Synergy IOL (Johnson & Johnson Vision). High and low contrast visual acuity, refractive, defocus curve, and patient-reported visual performance (Catquest-9SF questionnaire) outcomes were evaluated during a 3-month follow-up. RESULTS: A total of 96.1% (99 of 103) and 91.3% (94 of 103) of patients achieved binocular postoperative uncorrected distance (UDVA) and near visual acuity (UNVA) of 0.00 logMAR (20/20), respectively. Mean postoperative mesopic UNVA for both eyes was 0.14 ± 0.03 logMAR. Likewise, mean binocular UDVA and UNVA were 0.00 ± 0.03 and 0.04 ± 0.02 logMAR. An almost flat mean defocus curve was obtained, with visual acuities between 0.00 and 0.10 logMAR for most defocus levels in both eyes. A reduction of contrast led to a limited but statistically significant change in UNVA in both eyes (P < .001). The Rasch calibrated scoring of item 2 and the Rasch calibrated mean score of the Catquest-9SF questionnaire increased significantly with surgery (P < .001). CONCLUSIONS: This new presbyopia-correcting IOL provides a continuous range of functional focus, with a limited deterioration under mesopic conditions, which is perceived as a satisfactory outcome by the patient if proper patient selection is performed. [J Refract Surg. 2021;37(4):256-262.].

Predicted and Measured Changes in Posterior Corneal Astigmatism after Uncomplicated Femtosecond Assisted LASIK (FsLASIK) and Microkeratome LASIK Correction for Myopia and Low Astigmatism.

Purpose: To compare predicted and measured changes in astigmatism at the posterior corneal surface (PCS) after FsLASIK or LASIK.Methods: Astigmatism was measured at both corneal surfaces (PentacamTM) before and 3 months after unremarkable FFsLASIK (roup 1,n = 100) or LLASIK (roup 2,n = 100) for myopia (-7.25DS to -0.75DS) and low astigmatism (≤1.00DC). Photoablation was achieved using Schwind Amaris750STM laser (Aberration Free profile, centered on corneal vertex). Pre-and postop astigmatic data, according to subjective refraction and estimates for the corneal surfaces (over the central 3.2 mm zone), were subjected to vector analysis to calculate surgically induced astigmatism (SIA) by refraction (SIAR), at the anterior (SIAFact) and posterior corneal surfaces (SIABact). The difference vector between SIAR and SIAFact was regarded as the predicted SIA at the PCS (SIABest).Results: Reporting key findings. Mean(±sd,95%CI) SIABest and SIABact powers in group 1 were -0.52DC(±0.35,-0.56 to -0.45) and -0.11DC(±0.08,-0.13 to -0.10) in group 1, -0.35DC(0.20,-0.39 to -0.32) and -0.08DC(0.07,-0.09 to -0.06) in group 2. Differences between SIABest and SIABact were significant for powers but not axes. Significant correlations(p < .01) were revealed between (I) SIAR and SIAFact powers [Group 1, SIAR = 0.370.SIAFact-0.292,r = 0.299. Group 2, SIAR = 0.484.SIAFact-0.394,r = 0.519] but not the axes and (II) ΔC (difference between pre-[x1] and postop measured PCS astigmatic powers) and x1 [Group 1, ΔC = 0.384x1 + 0.119,r = 0.423. Group 2, ΔC = 0.135x1 + 0.047,r = 0.229,p = .022]. There was no correlation between SIABest and SIABact powers or axes.Conclusion: The changes in posterior corneal astigmatic powers according to Pentacam measurements are small and do not account for the deficit between SIAR and SIAFact after FsLASIK or LASIK.

Are changes in visual acuity and astigmatism after corneal cross-linking (CXL) in keratoconus predictable?

PURPOSE: To evaluate changes in corrected distance visual acuity (CDVA), ratio of anterior and posterior corneal radii over the thinnest region of the cornea (ARC/PRC), and astigmatism after cross-linking (CXL) in keratoconus. METHODS: Subjective refraction and ARC/PRC (using Pentacam™) were monitored over 1 year in (I) keratoconus treated with routine CXL (n = 53), (II) relatively stable keratoconus (n = 23), and (III) age/gender matched controls (n = 24). RESULTS: CDVA (median, mode, interquartile range) improved significantly in group I, compared with groups II and III (p < 0.05), from 0.45 (0.60, 0.20-0.63) to 0.80 (0.95, 0.60-0.95); change in CDVA was associated with preop CDVA (p < 0.01 at all times postop). ARC/PRC (mean ± sd, 95% CI) changed from 1.362 (± 0.048, 1.347-1.377) to 1.425 (± 0.073, 1.401-1.449). CDVA and ARC/PRC remained stable in II and III. Significant relationships were revealed between logCDVA and ARC/PRC in I and II (at 12 months, I rs = - 0.464, II rs - 0.449) and logCDVA at postop(y), log CDVA at preop(x1), and ARC/PRC at preop(x2) in I (at 12 months, y = 0.356x1 - 1.312x2 + 1.806, r21 = 0.494, r22 = 0.203). Astigmatic power (mean ± sd, 95% CI) improved from - 3.10DC (± 1.52, - 3.55 to - 2.66) to - 2.53DC (± 1.24, - 2.90 to - 2.17) in I, and worsened from - 1.27DC (± 1.32, - 1.81 to - 0.73) to - 1.61DC (± 1.28, - 2.13 to - 1.09) in II. Vector analysis revealed in group I (a) the power of the surgically induced astigmatism (SIA) was linked to astigmatic power at preop and (b) the difference between the axis of astigmatism at preop(ø) and the axis of the SIA was linked to ø. CONCLUSION: CXL improved CDVA, increased the ARC/PRC ratio, and modified the association between CDVA and ARC/PRC. The change in CDVA was linked to preop CDVA and ARC/PRC values. The association between SIA and preop astigmatism implies there is not a simple cause and effect relationship with CXL.

The relationship between patient age and residual refractive error after uneventful laser in situ keratomileusis for moderate-to-high hyperopia.

PURPOSE: To determine if the manifest sphero-cylindrical residual refractive error, at various time points over a 12-month postop period after laser in situ keratomileusis (LASIK) was associated with patient age at time of surgery. METHODS: Patients with moderate to high hyperopia (3.00-7.00 DS) and astigmatism ⩽2 DC underwent LASIK using Wavelight Allegretto Eye Q (400 Hz). Treatments were centered on corneal vertex, flaps were made with Moria M2 mechanical microkeratome. Pre-and postoperative uncorrected and corrected distant visual acuity, best corrected spherical equivalent (SEQ) were measured. Measurements were taken at 1 week, 1, 3, 6, and 12 months after the surgery. Target refraction was emmetropia. Total of 161 patients were treated. In binocular cases, data from the right eyes were included for analysis. In this article, we report on refraction data only. Raw data were subjected to several permutations to elicit any links between refractive outcomes and patient age. RESULTS: The key findings were as follows y = postop SEQ (diopters), x = patient age (years), ln(x) = natural logarithm of patient age: At 1 month, y = x[0.049 -0.011.ln(x)] (R = -0.205, p = 0.001, n = 161). At 3 months, y = x[0.077 -0.017.ln(x)] (R = -0.355, p < 0.001, n = 161). At 6 months, y = x[0.088 -0.020.ln(x)] (R = -0.382, p < 0.001, n = 161). At 12 months, y = x[0.093 -0.021.ln(x)] (R = -0.409, p < 0.001, n = 161). There was no significant association between x and y at 1 week (p > 0.05). CONCLUSION: Residual postop refractive error after LASIK for hyperopia has a logarithmic association with patient age at time of surgery. In younger patients there is tendency toward undercorrection, the opposite occurs in older patients and this persists 1 year after treatment.

Changes in the Higher Order Ocular Aberrations and Central Corneal Thickness After T-PRK and Fs-LASIK.

INTRODUCTION: Refractive surgery procedures, transepithelial photorefractive keratectomy (T-PRK), and femtosecond laser in situ keratomileusis (Fs-LASIK) are regarded as safe and efficacious methods for correcting myopia and myopic astigmatism. These two methods do not have many differences in results when treating spherical myopia while differences exist in the treatment of astigmatism correction. Vector analysis presents a powerful tool to show the real differences between these two methods regarding high ocular aberrations and central corneal thickness of treated eyes. AIM: The aim of the study is to investigate changes in higher order ocular aberrations (HOAs) and central corneal thickness (CCT) following treatment of myopia and myopic astigmatism above -5.00DS and up to -2.00DC after either T-PRK or Fs-LASIK. METHODS: Patients (30 eyes per group) underwent T-PRK (group I) or Fs-LASIK (group II) procedure using the Schwind Amaris 750S laser. HOAs (3mm&5mm pupil) and CCT were measured objectively at pre-, 1,3 & 6 months postop in each case. RESULTS: Key results at 6 months were: i) mean values of trefoil (5mm pupil) were 0.092µm (sd,0.055,95% CI 0.072 to 0.112) & 0.126µm (sd,0.078,95% CI 0.098 to 0.154) in group I, and 0.088µm (sd,0.058,95% CI 0.067 to 0.109) & 0.064µm (sd,0.034,95% CI 0.052 to 0.076) in group II (P=0.001 at 6 months); ii) Changes in CTT (ΔCTT) and best spherical equivalent correction (ΔBSE) was significant in group II (ΔCCT=-26.55[ΔBSE]-14.06,R=0.486,P=0.006) but not in group I (p=0.034). CONCLUSIONS: After T-PRK trefoil is worse than Fs-LASIK. The predictability of corneal changes is better following Fs-LASIK.

Pachymetry and Elevation Back Map Changes in Keratoconus Patients After Crosslinking Procedure.

INTRODUCTION: The crosslinking (CXL) procedure using the standard Dresden protocol is established as the gold standard for the treatment of progressive keratoconus. AIM: The aim of this paper is to correlate the pachymetry and elevation back map (EBM) changes in the period from 3 to12 months of keratoconus patients after the CXL procedure. M. METHODS: Forty-four eyes of 34 patients with keratoconus were analyzed after performed standard Dresden protocol CXL procedure. All of them underwent complete preoperative examination with a follow up of 12 months with a focus on pachymetry and EBM changes performed by Oculus Pentacam (Scheimpflug technology) analysis. RESULTS: Pachymetry changed significantly in 12 months post cross-linking, especially in the first 6 months after which it slightly increased. Differences in EBM preoperatively and 12 months postoperatively were not statistically significant. CONCLUSION: Corneal pachymetry in keratoconus patients decreases after the CXL procedure. Differences in pachymetry preoperatively and 3, 6 and 12 months postoperatively were statistically significant, but the value of corneal thickness increased from the third month to 12 months post-op. Differences in EBM preoperatively and 12 months postoperatively were not still statistically significant, which is good, because the increase in elevation, as one of the signs of progression of the keratoconus - did not occur.

Incidence of Keratoconus in Refractive Surgery Population of Vojvodina - Single Center Study.

INTRODUCTION: Keratoconus (KCN) is known to affect all ethnicities but its incidence exhibits geographical variability plausibly due to subclinical forms of the disease, differences in diagnostic methods and criteria, or differences in genetic variations in populations. AIM: To examine the prevalence of keratoconus among the refractive surgery population of Vojvodina, who underwent refractive surgery screening at Eye Clinic Svjetlost Novi Sad, Serbia from September 2018 to September 2019. This is a single-center study. METHODS: Retrospective analysis of 876 patients who presented for refractive surgery evaluation. Corneal tomographers represent the gold standard in the detection and classification of corneal ectatic diseases and screening is an essential part of the preoperative diagnostics before any refractive surgery. The corneal tomographer used in this study was a Scheimpflug imaging device (Pentacam AXL, Oculus Optikgeräte GmbH, Wetzlar, Germany). The device was realigned before each measurement. RESULTS: Out of a total number of patients, 619 (70,7%) were candidates for corneal refractive surgery procedure, and 257 patients (29.3%) were not. Out of 257 patients that were not candidates for the procedure 157 (61,0%) patients had thin corneas, high myopia/hypermetropia or had some retinal disease; 75 patients (29,1) were keratoconus suspect and 25 patients (9,7%) had keratoconus. KCN patients had a mean age of 29.5 ± 7.7 years, 18 patients (72.0%) were male and 7 patients were female (28%). CONCLUSION: The most cited annual incidence of KCN is 2 approximately 1 per 2,000. Recent data from the biggest Netherland study revealed many different epidemiological results which deprive keratoconus of the community of rare diseases. The incidence of keratoconus in Vojvodina refractive surgery population presented in our Clinic was 2.9%.

Keratoconus Progression Classification One Year After Performed Crosslinking Method Based on ABCD Keratoconus Grading System.

INTRODUCTION: Keratoconus is described as a degenerative bilateral, progressive, noninflammatory corneal disorder characterized by ectasia, thinning, and increased curvature. Keratoconus progression classification 1 year after performed crosslinking method in this study is based on the ABCD keratoconus grading system. AIM: To evaluate the possible keratoconus progression one year after performed a crosslinking (CXL) method based on the ABCD keratoconus grading system. Methods: Seventeen keratoconus patients (22 eyes) were included in this prospective study. CXL procedure was performed using the standard Dresden protocol at Eye Clinic Svjetlost Sarajevo with the inclusion period from January 2017 to January 2018. Twelve patients had monocular, and 5 patients had binocular treatments with follow up of 12 months. Preoperative and postoperative stages were compared using the ABCD keratoconus grading system measured on rotating Scheimpflug corneal tomography-based machine - Pentacam (Pentacam HR, Oculus Optikgeräte GmbH, Wetzlar, Germany). RESULTS: Out of 22 eyes, one eye had keratoconus stage I-II, 6 eyes had stage II, 4 eyes had stage III, and 9 eyes had stage III-IV. There was no statistically significant gradient change of keratoconus in comparison to one month after the surgery, p>0.05. There was no progression of the gradient when comparing to the preoperative stage. CONCLUSIONS: Corneal cross-linking could effectively stabilize the progression of keratoconus, as assessed by key corneal topographic parameters. Analyzing the trend of stage change in 12 months follow up after the crosslinking procedure of keratoconus patients there was no progression of a gradient in comparison to the preoperative stage. According to our results, we can conclude that CXL is a safe and effective procedure in treating keratoconus.

Vector Analysis of Changes in the Higher Order Ocular Aberrations and Central Corneal Thickness After T-PRK and Fs-LASIK.

INTRODUCTION: Refractive surgery procedures, transepithelial photorefractive keratectomy (T-PRK) and femtosecond laser in situ keratomileusis (Fs-LASIK) are regarded as safe and efficacious methods for correcting myopia and myopic astigmatism. These two methods do not have much differences in results when treating spherical myopia, while some differences does exist in treatment of myopic astigmatism. Vector analysis presents powerful tool to show the real differences between these two methods regarding higher order ocular aberrations and central corneal thickness of treated eyes. AIM: The aim of the study is to investigate changes in higher order ocular aberrations (HOAs) and central corneal thickness (CCT) following treatment of myopia and myopic astigmatism above -5.00DS and up to -2.00DC after either T-PRK or Fs-LASIK. METHODS: Patients (30 eyes per group) underwent T-PRK (group I) or Fs-LASIK (group II) procedure using Schwind Amaris 750S laser. HOAs (3mm&5mm pupil) and CCT were measured objectively at pre-, 1,3 & 6 months postop in each case. RESULTS: Key results at 6 months were: i) mean values of trefoil (5mm pupil) were 0.092µm (sd,0.055,95% CI 0.072 to 0.112) & 0.126µm (sd,0.078,95% CI 0.098 to 0.154) in group I, and 0.088µm (sd,0.058,95% CI 0.067 to 0.109) & 0.064µm (sd,0.034,95% CI 0.052 to 0.076) in group II (P=0.001 at 6 months); ii) Changes in CCT (ΔCCT) and best spherical equivalent correction (ΔBSE) was significant in group II (ΔCCT=-26.55[ΔBSE]-14.06,R=0.486,P=0.006) but not in group I (p=0.034). CONCLUSIONS: After T-PRK trefoil is worse than Fs-LASIK. The predictability of corneal changes is better following Fs-LASIK. .

Vector Analysis of Visual Acuity and Refractive Outcomes of Astigmatic Corrections After T-PRK and Fs-LASIK.

INTRODUCTION: T Transepithelial photorefractive keratectomy (T-PRK) and femtosecond laser in situ keratomileusis (Fs-LASIK) are reftactive surgery methods for treating myopia and myopic astigmatism. Although T-PRK obtains similar results to Fs-LASIK with spherical myopia, it has differences in astigmatism correction. Vector analysis is a perfect tool to see the real difference between these two methods regarding astigmatic refraction and visual acuity. AIM: The aim of the study is to investigate changes in astigmatism and visual acuity following treatment of myopia and myopic astigmatism above -5.00DS and up to -2.00DC after either T-PRK or Fs-LASIK. METHODS: Patients (30 eyes per group) underwent unremarkable T-PRK (group I) or Fs-LASIK (group II) using Schwind Amaris 750S laser. Astigmatic data acquired by subjective refraction were subjected to vector analysis to determine the association between surgically (SIA) and target induced (TIA) astigmatic powers and differences in axes(θ). RESULTS: Key results at 6 months were: i) Mean astigmatism changed from -0.92 DC (sd ±0.49,95%CI-1.10to-0.75) to -0.38 DC (sd ±0.40,95% CI-0.52 to -0.24) in group I and -0.93DC (sd±0.55,95%CI -1.07 to -0.67) to -0.14DC (sd±0.31,95% CI-0.25 to -0.03) in group II (P=0.005 at 6 months). ii) Mean (±sd) θ was +9.7° (±19.0°) in group I and -2.2° (±15.5°) in group II (P=0.005). CONCLUSION: There was a greater mismatch between SIA and TIA powers and axes after T-PRK. T-PRK tends to induce more unwanted astigmatism. The predictability of the refractive and optical changes is better following Fs-LASIK.

Cross-linking treatment for better visual acuity.

Aim To correlate the maximum anterior sagittal curvature (Kmax) changes and uncorrected (UDVA) and corrected distance visual acuity (CDVA) in keratoconus patients after the cross-linking (CXL) procedure. Methods Forty-four eyes of 34 patients with keratoconus were analysed after the standard Dresden protocol CXL procedure had been performed. All patients underwent complete preoperative examination with a follow-up of 12 months with focus on UDVA, CDVA and Oculus Pentacam (Scheimpflug technology) analysis. We analysed and correlated Kmax changes in the postoperative period of 12 months together with visual acuity changes. Results Visual acuity improved significantly in the first 3 months after the procedure and even more significantly until the end of the first year. Even Kmax is the most relevant and most followed parameter for progression and regression of keratoconus, its lowering was not directly correlated with the visual acuity improvement (both uncorrected and corrected) in the first 6 months after corneal CXL procedure. Kmax was changed significantly in the period of 12 months post cross linking, but not in the first 6 months. Conclusion Corneal CXL should be considered as a procedure not just for corneal stiffening and stabilization, but also for visual acuity improvement in keratoconus patients.