Refractive Outcomes After LASIK for the Treatment of Mixed Astigmatism with the Allegretto WaveLight EX500.

INTRODUCTION: Treatment of mixed astigmatism with laser in situ keratomileusis (LASIK) is complex as the correction requires flattening the cornea in one meridian while steepening the cornea in the other meridian. The bitoric technique has become the most popular approach and has been tested across a variety of platforms. This study is the first to evaluate the results of mixed astigmatism treatment using the Allegretto WaveLight® EX500. METHODS: This study was a single-center, retrospective, noncomparative analysis of 400 eyes that underwent LASIK to correct for mixed astigmatism utilizing the EX500 excimer laser. Data on uncorrected distance visual acuity, corrected distance visual acuity, and spherical equivalent was analyzed at consecutive intervals (1, 3, 6, 9, and 12 months). Refractive measurements were used to perform a vector analysis. RESULTS: Three and 12 months postoperatively, 71% and 74% of eyes had an uncorrected distance visual acuity (UDVA) of 20/20 or better and 99% and 100% of eyes had a UDVA of 20/40 or better, respectively. The postoperative UDVA was within one line of the corrected distance visual acuity (CDVA) in 88% and 93% of eyes at 3 and 12 months, respectively. At 3 months, 78% of eyes achieved refractive astigmatism no greater than 0.50 diopters and at 12 months, 80% achieved this. The mean spherical equivalent refraction was - 0.36 ± 0.57 D at 12 months after surgery. At the 12-month follow-up, the mean refractive cylinder was reduced by 87%, from - 2.79 to - 0.37 diopters. On vector analysis, 99% of eyes had an angle of error within ± 15° from the intended target at 3 and 12 months. CONCLUSION: Treatment of mixed astigmatism using the Allegretto WaveLight® EX500 laser exceeded the industry standards of safety, efficacy, stability, and accuracy.

Transepithelial phototherapeutic keratectomy for the treatment of severe band keratopathy.

PURPOSE: The goal of this study was to investigate the clinical outcomes of transepithelial phototherapeutic keratectomy (transepithelial PTK) for the treatment of severe band keratopathy. METHODS: A consecutive series of severe band keratopathy cases treated with transepithelial PTK were retrospectively analysed between January 2018 and December 2019. Severe band keratopathy was defined as corneal plaques apparent in the obscuration of iris details. Patients' medical histories, preoperative and postoperative symptomatic relief, cosmesis, best-corrected visual acuity (BCVA), complications, and recurrences were analysed. RESULTS: Seventeen eyes of 16 patients were included in the study, with a mean follow-up of 9.8 ± 5.2 months (3 to 19 months). The mean age of the patients was 15.8 ± 10.2 years (8 to 46 years). Symptoms were significantly or completely relieved in all patients (100%). The results of cosmesis were good in 14 eyes (82.4%). Among those eyes that had BCVA of hand motion or better preoperatively, seven eyes (100%) showed an improvement in BCVA postoperatively. There were no complications or recurrences associated with transepithelial PTK treatment during the follow-up period. CONCLUSIONS: Transepithelial PTK is an effective treatment to eliminate corneal opacity and alleviate symptoms in patients with severe band keratopathy. This technique could be an alternative approach to managing severe band keratopathy.

Centration in refractive surgery / Centralização em cirurgia refrativa

ABSTRACT The point of centration for refractive surgery is a theme of great importance that generates considerable discussion among specialists and surgeons in the field. Notably, any changes in light can alter the size of the pupil, and the visual axis of the fixation line to the fovea is unique in each patient. A variety of options have been described in the literature with respect to centration in refractive surgery, and the results differ among these methods. No consensus has been established regarding the ideal refractive surgery technique for evaluation of centration in each patient that will yield a satisfactory surgical result.

RESUMO O ponto de centralização da cirurgia refrativa é tema de grande importância e gera muita discussão entre especialistas e cirurgiões da área. Afinal, qualquer alteração na luz pode alterar o tamanho da pupila, além disso, o eixo visual da linha de fixação para a fóvea é particular em cada paciente. Existem opções para centralização em cirurgia refrativa com resultados diferentes na literatura. Ainda não há consenso sobre a melhor técnica em cirurgia refrativa que avalie cada caso específico visando um resultado cirúrgico final satisfatório.

Shielding effect of the smoke plume by the ablation of excimer lasers.

BACKGROUND: Shielding and scattering effect of the smoke plume column ejected from the laser ablated material is a well-known phenomenon. Debris evacuation system of the excimer laser equipment removes these particles, but insufficient air flow can result in undesired refractive outcomes of the treatment. The aim of this study was to reveal the effect of the air flow speed on the actual ablation depth. METHODS: SCWIND AMARIS 500E flying spot excimer laser was tested in this study. A 150 µm phototherapeutic keratectomy (PTK) profile with 8 mm diameter was applied to the surface of polymethyl methacrylate (PMMA) plates. The velocity of the air flow was changed with adjustable air aspiration system. Ablation depth was measured with highly-precise contact micrometer. RESULTS: The prediction model was statistically significant, F(1,8) = 552.85, p < 0.001, and accounted for approximately 98.7% of variance of ablation (R2 = 0.987, R2adj = 0.986). Lower air flow speed resulted in a weaker ablation capability of the excimer laser. CONCLUSION: Air flow generated by the aspiration equipment is a key factor for the predictable outcomes of refractive treatment. Therefore, manufacturer inbuilt debris removal system should be regularly checked and maintained to ensure proper clinical and predictable refractive results.

Effect of open ultraviolet germicidal irradiation lamps on functionality of excimer lasers used in cornea surgery.

We report on the impact of direct ultraviolet germicidal irradiation (UVGI) on reflective optics, used in the excimer laser system Allegretto Eye-Q. The aim of our work was to confirm our hypothesis based on long-rate observations of obtained anomalies in post-operative results that are attributed to degradation of reflective optics upon ultraviolet radiation. The presence of direct UVGI coupled with humidity in the operating environment caused merging anomalies and unwanted post-operative correction values. Ultraviolet-A radiation caused a similar effect on the reflective cover of the mirrors.

[Complications of corneal lamellar refractive surgery]. / Komplikationen der lamellären refraktiven Hornhautchirurgie.

Techniques available for corneal lamellar refractive surgery are laser-assisted in situ keratomileusis (LASIK) using a microkeratome or femtosecond laser incision followed by excimer laser corneal ablation, and femtosecond laser-assisted refractive lenticule extraction (ReLEx). These treatments are nowadays considered to be safe and effective standard procedures for surgical correction of mild to moderate ametropia. Possible complications include too small or decentered optical zones, intraoperative flap cutting errors and postoperative inflammation (e.g. diffuse lamellar keratitis, DLK), epithelial or flap folds, epithelial ingrowths or iatrogenic ectasia. The occurrence of complications may be significantly reduced by compliance to corresponding standards of indication and treatment that are based on current scientific knowledge.

Short-term efficacy of high-intensity ultraviolet B versus 308-nm excimer laser for the treatment of vitiligo / 中华皮肤科杂志

Objective To compare the short-term efficacy of high-intensity ultraviolet B (UVB) versus 308-nm excimer laser for the treatment of vitiligo.Methods Eighty patients with vitiligo were equally divided into two groups to be treated with high-intensity UVB twice a week or 308-nm excimer laser once a week for eight weeks.Repigmentation was evaluated at the end of the treatment.Results After eight weeks of treatment,repigmentation of different degrees was observed in 83.6％ and 86.1％,and marked repigmentation in 42.1％ and 50％,of the UVB-and excimer laser-treated lesions,respectively.The response rate was significantly lower in facial lesions receiving high-intensity UVB radiation than in those receiving excimer laser radiation (49.1％ vs.68.4％,x2 =4.32,P ＜ 0.05),but similar at the other body sites between the two treatment (all P ＞ 0.05).The cumulative dosage required for initial repigmentation was similar between high-intensity UVB and 308-nm excimer laser (t =0.89,P ＞ 0.05),while the treatment sessions and cumulative dosage required for marked or better repigmentation were significantly increased in UVB-compared with excimer laser-treated lesions (both P ＜ 0.01).In addition,both high-intensity UVB and 308-nm excimer laser were suitable for childhood and active vitiligo.Conclusions Both high-intensity UVB and 308-nm excimer laser are safe and effective in the treatment of vitiligo with rapid onset of action,and the latter appears to be superior to the former in efficacy.

Resultados refractivos posqueratoplastia lamelar anterior superficial con láser excimer guiado por topografía en queratocono grado III / Refractive results after topography-guided anterior lamellar keratoplasty with excimer laser in keratoconus grade III

Objetivo: determinar los resultados refractivos y funcionales en operados de queratoplastia lamelar anterior superficial asistida con láser excimer topográfico en queratocono grado III. Materiales y métodos: estudio experimental, abierto, no controlado, longitudinal y prospectivo, en 35 ojos de 31 pacientes con edad promedio de 35,3 años, seguimiento entre 12 y 51 meses, operados en la Clínica Internacional de Retinosis Pigmentaria "Camilo Cienfuegos", entre enero de 2006 y diciembre de 2010. Resultados: la agudeza visual sin corrección mejoró de 0,04 a 0,39 y la agudeza visual con corrección de 0,28 a 0,78; el equivalente esférico se redujo de -13,02 a -1,69; la esfera y el cilindro disminuyeron de -10,13D ± 4,73 a -0,44D ± 3,22 y de -5,67D ± 2,32 a -2,52D ± 1,38, respectivamente. La queratometría disminuyó de 56,8D y 51,53D a 45,02 y 42,02 en el postoperatorio. La densidad celular preoperatoria fue de 2313, 81 cel/mm2 ± 322,10; varió a 2170 cel/mm2 ± 294,92 en el posoperatorio. El lecho residual estromal fue de 153,22μ. Discusión: en correlación con la literatura, el queratocono se presenta en la adolescencia y juventud y conduce al trasplante de córnea con más frecuencia en estas etapas de la vida. La queratometría promedio posoperatoria fue inferior a la reportada por otros investigadores que realizaron estudios con semejante técnica quirúrgica. Conclusiones: la queratoplastia lamelar anterior superficial con láser excimer, puede ser considerada como indicación primaria de tratamiento en el queratocono grado III..

Objective: determine refractive and functional results in patients with excimer laser. Materials and Methods: uncontrolled experimental study, longitudinal and prospective, in 35 eyes of 31 patients with an average age of 35.3 years old, followed between 12 and 51 moths; operated at “Camilo Cienfuegos” International Center of Retinitis Pigmentosa, between January 2006 and December 2010. Results: the uncorrected visual acuity improved from 0.04 to 0.39 and the best corrected visual acuity improved from 0.28 to 0.78; the spherical equivalent was reduced from -13,02 to -1,69D. The sphere and cylinder decreased from -10,13D ± 4.73 to -0.44D ± 3.22 and from -5.67D ± 2.32 to -2.52D ± 1.38, respectively. The average of the keratometry decreased from 56,8D and 51,53D to 45.02 and 42.02 in the post-surgery. The cellular density pre-surgery changed from 2313.81cel/mm2 ± 322.10 to 2170 cel/mm2 ± 294.92 in postoperative. The residual stromal bed was 153.22μ. Discussion: in correlation with the literature, the keratoconus appears in the adolescence and youth, leading to the corneal transplantation more often in these life stages. The average postsurgical keratometry was inferior to the reported by others investigators who practiced procedures with similar surgical technique. Conclusions: superficial anterior lamellar keratoplasty, assisted with excimer laser, can be considered as primary indication of treatment in keratoconus grade III..

Combined ethylenediaminetetraacetic acid chelation, phototherapeutic keratectomy and amniotic membrane transplantation for treatment of band keratopathy.

PURPOSE: The objective of this study is to evaluate the therapeutic efficacy of ethylenediaminetetraacetic acid (EDTA) chelation and excimer laser phototherapeutic keratectomy (PTK) combined with amniotic membrane transplantation (AMT) for the treatment of band keratopathy (BK). METHODS: Eleven eyes in ten patients with BK received combined PTK (ablation zone of central 7.0-7.5 mm, depth of 50 microm), EDTA chelation (0.05 M, 3 minutes), and amniotic membrane transplantation using fibrin glue. Preand postoperative best corrected visual acuities, symptom changes, reepithelialization time, cosmesis, recurrence, and complications were analyzed. RESULTS: Visual acuity improved in three eyes (27.3%) and did not change in eight eyes (72.7%). Symptoms improved in all patients, and the mean reepithelialization time was 10.6+/-5.3 days. The cosmetic results were good in eight eyes (72.7%) and were fair in three eyes (27.3%). During the mean follow-up period of 11.4+/-6.1 months (range, 6 to 23 months), no postoperative complications or recurrences were observed. CONCLUSIONS: The combination of EDTA chelation, PTK, and AMT is safe and effective for the treatment of band keratopathy.

Combined Ethylenediaminetetraacetic Acid Chelation, Phototherapeutic Keratectomy and Amniotic Membrane Transplantation for Treatment of Band Keratopathy

PURPOSE: The objective of this study is to evaluate the therapeutic efficacy of ethylenediaminetetraacetic acid (EDTA) chelation and excimer laser phototherapeutic keratectomy (PTK) combined with amniotic membrane transplantation (AMT) for the treatment of band keratopathy (BK). METHODS: Eleven eyes in ten patients with BK received combined PTK (ablation zone of central 7.0-7.5 mm, depth of 50 microm), EDTA chelation (0.05 M, 3 minutes), and amniotic membrane transplantation using fibrin glue. Preand postoperative best corrected visual acuities, symptom changes, reepithelialization time, cosmesis, recurrence, and complications were analyzed. RESULTS: Visual acuity improved in three eyes (27.3%) and did not change in eight eyes (72.7%). Symptoms improved in all patients, and the mean reepithelialization time was 10.6+/-5.3 days. The cosmetic results were good in eight eyes (72.7%) and were fair in three eyes (27.3%). During the mean follow-up period of 11.4+/-6.1 months (range, 6 to 23 months), no postoperative complications or recurrences were observed. CONCLUSIONS: The combination of EDTA chelation, PTK, and AMT is safe and effective for the treatment of band keratopathy.