Twenty-five-gauge trocar anterior chamber maintainer: New device for infusion.

The technique, feasibility, and results of a new 25-gauge trocar-anterior chamber maintainer (ACM) designed for maintaining intraoperative fluid infusion is described in this prospective interventional analysis. The 25-gauge trocar-ACM with an overall length of the trocar blade of 6.0 mm, cannula length of 4.0 mm, and the cannula tip beveled at 45 degrees to the base was designed and used in all the cases. The dimensions of the sclerotomy wound that comprised of the internal ostium, external ostium, wound length, and the time interval for wound apposition in the postoperative period was analyzed by spectral-domain anterior segment optical coherence tomography.

Review of technological advancements in calibration systems for laser vision correction.

Using PubMed and our internal database, we extensively reviewed the literature on the technological advancements in calibration systems, with a motive to present an account of the development history, and latest developments in calibration systems used in refractive surgery laser systems. As a second motive, we explored the clinical impact of the error introduced due to the roughness in ablation and its corresponding effect on system calibration. The inclusion criterion for this review was strict relevance to the clinical questions under research. The existing calibration methods, including various plastic models, are highly affected by various factors involved in refractive surgery, such as temperature, airflow, and hydration. Surface roughness plays an important role in accurate measurement of ablation performance on calibration materials. The ratio of ablation efficiency between the human cornea and calibration material is very critical and highly dependent on the laser beam characteristics and test conditions. Objective evaluation of the calibration data and corresponding adjustment of the laser systems at regular intervals are essential for the continuing success and further improvements in outcomes of laser vision correction procedures.

Retrospective Analysis of the Post-Operative Changes in Higher-Order Aberrations: A Comparison of the WaveLight EX500 to the VISX S4 Laser in Refractive Surgery.

INTRODUCTION: In an attempt to maximize treatment outcomes, refractive surgery techniques are being directed toward customized ablations to correct not only lower-order aberrations but also higher-order aberrations specific to the individual eye. Measurement of the entirety of ocular aberrations is the most definitive means to establish the true effect of refractive surgery on image quality and visual performance. Whether or not there is a statistically significant difference in induced higher-order corneal aberrations between the VISX Star S4 (Abbott Medical Optics, Santa Ana, California) and the WaveLight EX500 (Alcon, Fort Worth, Texas) lasers was examined. METHODS: A retrospective analysis was performed to investigate the difference in root-mean-square (RMS) value of the higher-order corneal aberrations postoperatively between two currently available laser platforms, the VISX Star S4 and the WaveLight EX500 lasers. The RMS is a compilation of higher-order corneal aberrations. Data from 240 total eyes of active duty military or Department of Defense beneficiaries who completed photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK) refractive surgery at the Wilford Hall Ambulatory Surgical Center Joint Warfighter Refractive Surgery Center were examined. Using SPSS statistics software (IBM Corp., Armonk, New York), the mean changes in RMS values between the two lasers and refractive surgery procedures were determined. A Student t test was performed to compare the RMS of the higher-order aberrations of the subjects' corneas from the lasers being studied. A regression analysis was performed to adjust for preoperative spherical equivalent. The study and a waiver of informed consent have been approved by the Clinical Research Division of the 59th Medical Wing Institutional Review Board (Protocol Number: 20150093H). RESULTS: The mean change in RMS value for PRK using the VISX laser was 0.00122, with a standard deviation of 0.02583. The mean change in RMS value for PRK using the WaveLight EX500 laser was 0.004323, with a standard deviation of 0.02916. The mean change in RMS value for LASIK using the VISX laser was 0.00841, with a standard deviation of 0.03011. The mean change in RMS value for LASIK using the WaveLight EX500 laser was 0.0174, with a standard deviation of 0.02417. When comparing the two lasers for PRK and LASIK procedures, the p values were 0.431 and 0.295, respectively. CONCLUSION: The results of this study suggest no statistically significant difference concerning induced higher-order aberrations between the two laser platforms for either LASIK or PRK. Overall, the VISX laser did have consistently lower induced higher-order aberrations postoperatively, but this did not reach statistical significance. It is likely the statistical significance of this study was hindered by the power, given the relatively small sample size. Additional limitations of the study include its design, being a retrospective analysis, and the generalizability of the study, as the Department of Defense population may be significantly different from the typical refractive surgery population in terms of overall health and preoperative refractive error. Further investigation of visual outcomes between the two laser platforms should be investigated before determining superiority in terms of visual image and quality postoperatively.

Contrasting cellular damage after Blue-IRIS and Femto-LASIK in cat cornea.

Blue-intra-tissue refractive index shaping (Blue-IRIS) is a new approach to laser refractive correction of optical aberrations in the eye, which alters the refractive index of the cornea rather than changing its shape. Before it can be implemented in humans, it is critical to establish whether and to what extent, Blue-IRIS damages the cornea. Here, we contrasted the impact of -1.5 D cylinder refractive corrections inscribed using either Blue-IRIS or femtosecond laser in-situ keratomileusis (femto-LASIK) on corneal cell viability. Blue-IRIS was used to write a -1.5 D cylinder gradient index (GRIN) lens over a 2.5 mm by 2.5 mm area into the mid-stromal region of the cornea in six freshly-enucleated feline eyes. The same correction (-1.5 D cylinder) was inscribed into another four cat eyes using femto-LASIK. Six hours later, all corneas were processed for histology and stained for terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling (TUNEL) and p-γ-H2AX to label damaged cells. In Blue-IRIS-treated corneas, no tissue was removed and TUNEL-stained cells were confined to the laser focal zone in the stroma. In femto-LASIK, photoablation removed 14 µm of anterior stroma, but in addition, TUNEL-positive cells clustered across the femto-flap, the epithelium at the flap edges and the stroma below the ablation zone. Keratocytes positive for p-γ-H2AX were seen adjacent to all Blue-IRIS focal zones, but were completely absent from femto-LASIK-treated corneas. Unlike femto-LASIK, Blue-IRIS attains refractive correction in the cornea without tissue removal and only causes minimal, localized keratocyte death within the laser focal zones. In addition, Blue-IRIS induced DNA modifications associated with phosphorylation of γ-H2AX in keratocytes adjacent to the laser focal zones. We posit that this p-γ-H2AX response is related to alterations in chromatin structure caused by localized changes in osmolarity, a possible mechanism for the induced refractive index changes.

Comparing the Zeiss Callisto Eye and the Alcon Verion Image Guided System Toric Lens Alignment Technologies.

PURPOSE: To compare the alignment meridian generated by the Zeiss Callisto Eye (Carl Zeiss AG, Dublin, CA) and the Alcon Verion Image Guided System (Alcon Laboratories, Inc., Fort Worth, TX). METHODS: In this retrospective comparative evaluation of technology, intraoperative images were captured at different steps in the same surgery, allowing the comparison of the guidance lines generated by the Verion system to the parallel guidance lines generated by the Callisto Eye system. Measurements of each hemi-meridian were quantified using Adobe Photoshop 2015 CC software (Adobe Systems, San Jose, CA). The numbers of degrees separating these alignment meridians were calculated, entered into a database, and analyzed. RESULTS: The authors found that of 98 captured images of 16 eyes, the two technologies were identical in 0 eyes (θ1 = θ2 = 0), similar by 3° in 52 (53%) captured images (θ1 ≠ θ2 ≠ 0), and different by at least 3° in 46 (47%) captured images (θ1 ≠ θ2 ≠ 0). The target meridians were superimposed, the target lines were minimally separated, and the target lines were dissimilar. It was noted that some intraoperative variation occurred from measurement to measurement. Within the small group of 16 cases of routine toric lens implantation in this study, the absolute average number of degrees of misalignment between the Verion and Callisto Eye systems was 3.355 for θ1 and 3.838 for θ2. On average, the intraoperative variation termed "drift" was noted to be 3.963° for θ1, and 4.557° for θ2. CONCLUSIONS: The authors found that small deviations were frequent when comparing two sophisticated technologies. Although deviations greater than 3° occurred in less than 47% of captured images from 16 eyes, smaller but significant variations of less than 3° occurred in 53% of captured images from 16 eyes. It was rare to identify a large deviation. However, the authors identified "drift" in the same eye when measurements were taken at different times. The results indicate that the two systems are not currently interchangeable. Superiority of one system over the other was not determined. [J Refract Surg. 2017;33(7):482-487.].

Femto-lasik: The recent innovation in laser assisted refractive surgery.

Femtosecond laser has been introduced in refractive surgery to create a thin-hinged corneal flap without using any blade. The current review was planned to analyse and compare femtosecond-assisted laser in-situ keratomileusis (LASIK), the latest refractive procedure, with conventional techniques in refractive surgery. The analysis showed that femtosecond-assisted LASIK yielded more predictable corneal flaps, lesser ocular aberrations, better uncorrected visual acuity, lesser variations in intraocular pressure (IOP) and fewer chances of developing dry eyes. Transient light sensitivity, diffuse lamellar keratitis, opaque bubble layer, corneal haze and rainbow glare are some of the demerits of femtosecond-assisted LASIK, but these can be prevented with certain precautions. The early visual rehabilitation and preservation of corneal anatomy are added benefits in the long run. Though it is expensive currently, the competition in market is expected to cut down the cost soon.

[Results of residual ametropia correction using CIRCLE technology after femtosecond laser SMILE surgery]. / Rezul'taty ustraneniya ostatochnoi ametropii metodom CIRCLE posle lazernykh operatsii po tekhnologii SMILE.

AIM: to evaluate functional results of reoperation performed according to the CIRCLE technology and using the VisuMax femtosecond laser and MEL-80 excimer laser in cases of regression of the refractive effect after SMILE surgery. MATERIAL AND METHODS: We studied a group of post-SMILE patients. In those, who showed regression of the refractive effect at 1 year, reoperation was performed according to the CIRCLE technology and using the VisuMax femtosecond laser. The corneal flap was separated from the stromal bed and turned aside. Excimer laser ablation of the stromal bed was performed with the MEL 80 machine. The corneal flap was then placed back and rinsed from both sides. Uncorrected (UCVA) and corrected (BCVA) visual acuity as well as spherical equivalent (SE) were estimated before reoperation, on day 1, and at 1 month. RESULTS: After reoperation, BCVA and UCVA improved. Patient refraction became close to emmetropia. Specifically, UCVA was 0.23±0.18 at baseline (i.e. 1 year after SMILE) and 0.93±0.11 after the CIRCLE procedure (p<0.05). The absolute value of SE was 1.86±1.15 D and 0±0 D before and after CIRCLE, respectively (p<0.05). BCVA change was not statistically significant - from 0.95±0.1 to 0.93±0.11 (p>0.05). CONCLUSION: Reoperation performed according to the CIRCLE technology and using the VisuMax femtosecond laser and MEL-80 excimer laser provides an increase in visual acuity in case of post-SMILE regression of the refractive effect.

[Flexible Guidance of Ultra-Short Laser Pulses in Ophthalmic Therapy Systems]. / Flexible Führung ultrakurzer Laserpulse in ophthalmologischen Therapiesystemen.

In the last 20 years, the role of ultrashort pulsed lasers in ophthalmology has become increasingly important. However, it is still impossible to guide ultra-short laser pulses with standard glass fibres. The highly energetic femtosecond pulses would destroy the fibre material, and non-linear dispersion effects would significantly change beam parameters. In contrast, photonic crystal fibres mainly guide the laser pulses in air, so that absorption and dispersive pulse broadening have essentially no effect. This article compares classical beam guidance with mirrors, lenses and prisms with photonic crystal fibres and describes the underlying concepts and the current state of technology. A classical mirror arm possesses more variable optical properties, while the HCF (Hollow-Core Photonic Crystal Fibre) must be matched in terms of the laser energy and the laser spectrum. In contrast, the HCF has more advantages in respect of handling, system integration and costs. For applications based on photodisruptive laser-tissue interaction, the relatively low damage threshold of photonic crystal fibres compared to classic beam guiding systems is unacceptable. If, however, pulsed laser radiation has a sufficiently low peak intensity, e.g. as used for plasma-induced ablation, photonic crystal fibres can definitely be considered as an alternative solution to classic beam guidance.

[Intraoperative Measurement of Refraction with a Hand-Held Autorefractometer]. / Intraoperative Refraktionsmessung mit einem handgehaltenen Autorefraktometer.

PURPOSE: The aim of this study was to evaluate an intraoperative measurement of objective refraction with a hand-held retinomax instrument. METHODS: At the end of cataract surgery objective refraction in a lying position was measured with a retinomax instrument. On the first postoperative day the same measurement was performed with a retinomax and a standard autorefractometer. To evaluate the differences between measurements, the spherical equivalent (SE) and Jackson's cross cylinder at 0° (J0) and 45° (J45) was used. RESULTS: 103 eyes were included. 95 of them had normal cataract surgery. Differences between retinomax at the operative day and the standard autorefractometer were 0.68 ± 2.58 D in SE, 0.05 ± 1.4D in J0 and 0.05 ± 1.4D in J45. There were no statistically significant differences between the groups. CONCLUSION: Intraoperative measurement of the refraction with a retinomax can predict the postoperative refraction. Nevertheless, in a few patients great differences may occur.

The subject-fixated coaxially sighted corneal light reflex: a clinical marker for centration of refractive treatments and devices.

PURPOSE: To describe the inconsistencies in definition, application, and usage of the ocular reference axes (optical axis, visual axis, line of sight, pupillary axis, and topographic axis) and angles (angle kappa, lambda, and alpha) and to propose a precise, reproducible, clinically defined reference marker and axis for centration of refractive treatments and devices. DESIGN: Perspective. METHODS: Literature review of papers dealing with ocular reference axes, angles, and centration. RESULTS: The inconsistent definitions and usage of the current ocular axes, as derived from eye models, limit their clinical utility. With a clear understanding of Purkinje images and a defined alignment of the observer, light source/fixation target, and subject eye, the subject-fixated coaxially sighted corneal light reflex can be a clinically useful reference marker. The axis formed by connecting the subject-fixated coaxially sighted corneal light reflex and the fixation point, the subject-fixated coaxially sighted corneal light reflex axis, is independent of pupillary dilation and phakic status of the eye. The relationship of the subject-fixated coaxially sighted corneal light reflex axis to a refined definition of the visual axis without reference to nodal points, the foveal-fixation axis, is discussed. The displacement between the subject-fixated coaxially sighted corneal light reflex and pupil center is described not by an angle, but by a chord, here termed chord mu. The application of the subject-fixated coaxially sighted corneal light reflex to the surgical centration of refractive treatments and devices is discussed. CONCLUSION: As a clinically defined reference marker, the subject-fixated coaxially sighted corneal light reflex avoids the shortcomings of current ocular axes for clinical application and may contribute to better consensus in the literature and improved patient outcomes.

[Femtosecond lasers for cataract and refractive lens surgery]. / Femtosekundenlaser für die Katarakt- und refraktive Linsenchirurgie.

The femtosecond laser technology continues its progress in ophthalmology and now also plays an increasingly important role in lens surgery. Using this technology it is possible to create corneal sections and to perform capsulorhexis and lens fragmentation. There are currently four instruments on the market with more to follow. The individual benefits and also critical issues are presented and the results of current studies are discussed.

PROSE for irregular corneas at a tertiary eye care center.

OBJECTIVE: The aim of this study was to report and discuss the clinical experience with PROSE (Prosthetic Replacement of Ocular Surface Ecosystem) practice at a tertiary eye care hospital. METHODS: Retrospective data of patients who were prescribed PROSE during April 2011 to March 2012 in a tertiary eye care center in south India were analyzed. Data collected include patient demographics, indications of scleral lens fitting, previous correction modality, PROSE parameters, best-corrected visual acuity (BCVA) with spectacles, and BCVA with PROSE at initial assessment and few hours of wear. The BCVA before (with glasses) and after PROSE fitting was recorded in logMAR units. RESULTS: The age of the patients ranged between 13 and 68 years (male:female 60:25) with a mean age of 32.44±13.45 years. Mean BCVA improved by 0.3 logMAR units (3 lines) after fitting with PROSE. There was a statistically significant difference between pre- and post-PROSE BCVA (P=0.0001). Failure of rigid gas-permeable lens fitting or intolerance was the common indication for PROSE in corneas with irregular astigmatism (refractive conditions). The other reasons for which PROSE was prescribed were pain, photophobia, comfort, ghosting of images, and frequent loss of smaller lenses. Toric scleral haptic was indicated in 62 eyes. The diameter, vault, and haptic measurements of PROSE in ocular surface disorders were much less and flatter than that of refractive conditions. CONCLUSIONS: PROSE device is a very useful alternative for irregular corneas to improve visual acuity, to improve comfort, and for symptomatic relief.

[Contemporary refractive surgical procedures]. / Les techniques chirurgicales endoculaires modernes.

Ocular surgery has progressed a great deal these last decades thanks to technological progress. The aim of this article is to describe different contemporary endocular surgical procedures such as cataract surgery, vitreoretinal surgery and corneal grafts. The main indications of the surgeries will be discussed, as well as the type of anaesthesia, the practical issues of every surgical technique and the type and rates of the different complications.

Configuración del Pentacam en el tamizaje de cirugía refractiva / Pentacam configuration in refractive surgery screening

Objetivo: determinar la consistencia de la configuración manual del Pentacam en el tamizaje de cirugía refractiva. Métodos: se realizó un estudio observacional, descriptivo en el Instituto Cubano de Oftalmología Ramón Pando Ferrer durante el 2012. La muestra quedó conformada por 104 imágenes correspondiente a ojos examinados por el Pentacam que cumplieron los criterios de selección. Se analizaron variables tales como: diámetro para al cálculo de la esfera de mejor ajuste, elevación anterior, elevación posterior y se utilizó la clasificación de ectasias corneales según elevación anterior y posterior para agrupar la muestra. Resultados: del total de la muestra el 45,2 por ciento y el 54,8 por ciento utilizó un diámetro menor de 8 mm, y mayor de 8 mm para el cálculo de la esfera de mejor ajuste, respectivamente. La comparación de media de los dos grupos fue estadísticamente significativa. Según la clasificación de ectasia por elevación anterior y posterior, con un diámetro mayor de 8 mm se duplican en por ciento los exámenes normales y disminuyen los patológicos en un 25 porciento respectivamente. Existen diferencias entre las medias y la desviación estándar de los exámenes evolutivos a un mismo ojo según la configuración automática y manual. Conclusiones: la configuración manual del Pentacam permite tener una consistencia en el tamizaje de cirugía refractiva

Objective: to determine the consistency of manual Pentacam configuration in refractive surgery screening. Methods: observational and descriptive study performed at Ramon Pando Ferrer Cuban Institute of Ophthalmology during 2012. The sample was made up of 104 images of eyes examined by Pentacam equipment, which had met the selection criteria. The analyzed variables were diameter for best fit sphere calculation, anterior elevation, posterior elevation and the classification of corneal ectasias based on anterior and posterior elevations was used in order to group the sample. Results: in the sample, 45.2 percent and 54.8 percent used a diameter lower than 8mm and over 8mm for the calculation of the best fit sphere, respectively. The mean comparison between the two groups was statistically significant. According to the ectasia classification based on anterior and posterior elevations, with the over 8mm diameter, the normal exams doubled in some percentage and the pathological ones decreased by 25 percent, respectively. There are differences between the means and the standard deviations in evolutional exams performed in the same eye, considering the automatic and the manual configurations. Conclusions: manual configuration of Pentacam allows attaining consistency in the refractive surgery screening

Configuración del Pentacam en el tamizaje de cirugía refractiva / Pentacam configuration in refractive surgery screening

Objetivo: determinar la consistencia de la configuración manual del Pentacam en el tamizaje de cirugía refractiva. Métodos: se realizó un estudio observacional, descriptivo en el Instituto Cubano de Oftalmología Ramón Pando Ferrer durante el 2012. La muestra quedó conformada por 104 imágenes correspondiente a ojos examinados por el Pentacam que cumplieron los criterios de selección. Se analizaron variables tales como: diámetro para al cálculo de la esfera de mejor ajuste, elevación anterior, elevación posterior y se utilizó la clasificación de ectasias corneales según elevación anterior y posterior para agrupar la muestra. Resultados: del total de la muestra el 45,2 por ciento y el 54,8 por ciento utilizó un diámetro menor de 8 mm, y mayor de 8 mm para el cálculo de la esfera de mejor ajuste, respectivamente. La comparación de media de los dos grupos fue estadísticamente significativa. Según la clasificación de ectasia por elevación anterior y posterior, con un diámetro mayor de 8 mm se duplican en por ciento los exámenes normales y disminuyen los patológicos en un 25 porciento respectivamente. Existen diferencias entre las medias y la desviación estándar de los exámenes evolutivos a un mismo ojo según la configuración automática y manual. Conclusiones: la configuración manual del Pentacam permite tener una consistencia en el tamizaje de cirugía refractiva(AU)

Objective: to determine the consistency of manual Pentacam configuration in refractive surgery screening. Methods: observational and descriptive study performed at Ramon Pando Ferrer Cuban Institute of Ophthalmology during 2012. The sample was made up of 104 images of eyes examined by Pentacam equipment, which had met the selection criteria. The analyzed variables were diameter for best fit sphere calculation, anterior elevation, posterior elevation and the classification of corneal ectasias based on anterior and posterior elevations was used in order to group the sample. Results: in the sample, 45.2 percent and 54.8 percent used a diameter lower than 8mm and over 8mm for the calculation of the best fit sphere, respectively. The mean comparison between the two groups was statistically significant. According to the ectasia classification based on anterior and posterior elevations, with the over 8mm diameter, the normal exams doubled in some percentage and the pathological ones decreased by 25 percent, respectively. There are differences between the means and the standard deviations in evolutional exams performed in the same eye, considering the automatic and the manual configurations. Conclusions: manual configuration of Pentacam allows attaining consistency in the refractive surgery screening(AU)

Functional and visual improvement with prosthetic replacement of the ocular surface ecosystem scleral lenses for irregular corneas.

PURPOSE: To evaluate the Doheny Eye Institute Experience with Prosthetic Replacement of the Ocular Surface Ecosystem (PROSE) scleral lenses for the management of irregular corneas with outcomes based on visual acuity (VA) and visual function. METHODS: A retrospective chart review of 58 subjects (90 eyes) with irregular corneal surfaces referred to the Doheny Eye Institute for PROSE treatment between July 2009 and December 2011 was performed. The best-corrected VA before and after PROSE fitting was recorded. A functional assessment before and after PROSE fitting was also performed using the Ocular Surface Disease Index, a 12-item questionnaire that grades the severity of ocular discomfort and vision-related function. RESULTS: Keratoconus (43%) represented the largest group, and post-PK astigmatism (31%) represented the second largest group of patients with irregular corneas who had completed the PROSE treatment. Patients with keratoconus had the greatest improvement in VA after PROSE fitting with an 88% improvement in the logarithm of the minimal angle of resolution vision. Patients with post-PK astigmatism had the greatest improvement in Ocular Surface Disease Index scores with a 79% improvement observed after PROSE fitting. CONCLUSIONS: PROSE scleral lenses offer improvements in the VA and function, and they could be an option for patients with irregular corneas who have failed conventional treatments before considering additional surgery.

[Understanding the advantages and disadvantages of femtosecond laser comprehensive applications in ophthalmology].

The femtosecond (FS) laser is a novel laser technology, and is approved clinical application by FDA in 2000. FS laser initially mainly used in corneal refractive surgery to replace the mechanical microkeratome. Since the accuracy and controllability of the FS laser is very high, it shows superiority in the field of corneal refractive surgery. And with the development of the relative hard and software, FS laser is began to used in other fields of ophthalmology, such as corneal transplants, cataract surgery, as well as assisted diagnosis et al., although still have some limitations, the preliminary clinical results have been shown a very good prospects in the ophthalmology fields. Therefore, we reviewed the alternative applications, challenges and limitations, research direction in the future of FS laser, so that provide a reference and revelations for the peers.