Samuel Arba Mosquera

Publications (64) View all

• Article: Theoretical analyses of the refractive implications of transepithelial PRK ablations.

  Samuel Arba Mosquera, Shady T Awwad
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  ABSTRACT: BACKGROUND/AIMS: To analyse the refractive implications of single-step, transepithelial photorefractive keratectomy (TransPRK) ablations. METHODS: A simulation for quantifying the refractive implications of TransPRK ablations has been developed. The simulation includes a simple modelling of corneal epithelial profiles, epithelial ablation profiles as well as refractive ablation profiles, and allows the analytical quantification of the refractive implications of TransPRK in terms of wasted tissue, achieved optical zone (OZ) and induced refractive error. RESULTS: Wasted tissue occurs whenever the actual corneal epithelial profile is thinner than the applied epithelial ablation profile, achieved OZ is reduced whenever the actual corneal epithelial profile is thicker than the applied epithelial ablation profile and additional refractive errors are induced whenever the actual difference centre-to-periphery in the corneal epithelial profile deviates from the difference in the applied epithelial ablation profile. CONCLUSIONS: The refractive implications of TransPRK ablations can be quantified using simple theoretical simulations. These implications can be wasted tissue (∼14 µm, if the corneal epithelial profile is thinner than the ablated one), reduced OZ (if the corneal epithelial profile is thicker than ablated one, very severe for low corrections) and additional refractive errors (∼0.66 D, if the centre-to-periphery progression of the corneal epithelial profile deviates from the progression of the ablated one). When TransPRK profiles are applied to normal, not previously treated, non-pathologic corneas, no specific refractive implications associated to the transepithelial profile can be anticipated; TransPRK would provide refractive outcomes equal to those of standard PRK. Adjustments for the planned OZ and, in the event of retreatments, for the target sphere can be easily derived.
  The British journal of ophthalmology 04/2013; · 2.92 Impact Factor
• Article: Influence of patient age on high myopic correction in corneal laser refractive surgery.

  Michiel H A Luger, Tobias Ewering, Samuel Arba-Mosquera
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  ABSTRACT: PURPOSE: To evaluate the influence of patient age on the postoperative outcomes in eyes with myopia higher than 5.00 diopters (D) that had laser in situ keratomileusis using the Schwind Amaris laser system. SETTING: Private practice, Utrecht, The Netherlands. DESIGN: Case series. METHODS: At the 1-year follow-up, right eyes with preoperative myopia higher than 5.00 D were analyzed. The effect of the patient's age on postoperative status was assessed using univariate linear and multilinear correlations. RESULTS: The study analyzed 612 eyes. Univariate linear analyses showed that residual refraction was correlated with patient age. Univariate multilinear analyses showed that spherical equivalent (SE) was correlated with the attempted SE and patient age, whereas cylinder was correlated with attempted cylinder only. Analyses suggested overcorrections and higher residual astigmatism values for older patients. CONCLUSIONS: Patient age affected postoperative outcomes in a subtle, yet significant manner. An age-dependent adjustment toward greater attempted correction in younger patients and less intended correction in older patients may help optimize refractive outcomes. FINANCIAL DISCLOSURE: Drs. Ewering and Arba-Mosquera are employees of Schwind eye-tech-solutions GmbH. Dr. Luger has no financial or proprietary interest in any material or method mentioned.
  Journal of cataract and refractive surgery 02/2013; 39(2):204-210. · 2.75 Impact Factor
• Article: Uncorrected Binocular Performance after Biaspheric Ablation Profile for Presbyopic Corneal Treatment Using AMARIS with the PresbyMAX Module.

  Pierre Baudu, Franck Penin, Samuel Arba Mosquera
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  ABSTRACT: PURPOSE: To analyze the uncorrected binocular performance after biaspheric multifocal central presbyopic laser in situ keratomileusis treatments. DESIGN: Retrospective, interventional case series. METHODS: Setting. Private clinical practice. Patient or study population. Three hundred fifty-eight presbyopic patients (43% males, 82 myopic), bilaterally treated, suitable for laser in situ keratomileusis, with monocular corrected distance visual acuity of 20/32 or better. Intervention or observation procedure(s). PresbyMAX (Schwind Eye-Tech-Solutions GmbH and Co. KG, Kleinostheim, Germany) biaspheric multifocal ablation. Main outcome measures. Binocular uncorrected distance visual acuity (UDVA) and near visual acuity (UNVA) after surgery and their changes compared with corrected distance visual acuity and corrected near visual acuity before surgery. RESULTS: At 6 months, 76% of patients achieved a UDVA of 0.1 logarithm of the minimal angle of resolution (logMAR; Snellen equivalent, 20/25) or better, 91% of patients obtained a UNVA of 0.1 logarithmic of the reading acuity determination (logRAD) (p3) or better, and 99% of patients were within 1 diopter of defocus. Postoperative mean spherical equivalent was -0.17 ± 0.34 diopter. Ninety-six percent of patients achieved a UDVA of 0.2 logMAR (Snellen equivalent, 20/32) or better and a UNVA of 0.2 logRAD (p4) or better. Mean binocular corrected distance visual acuity degraded from 0.00 ± 0.01 logMAR (Snellen equivalent, 20/20) to a UDVA of 0.09 ± 0.07 logMAR (Snellen equivalent, 20/25). Mean binocular corrected near visual acuity degraded from 0.02 ± 0.01 logRAD (p2) to a UNVA of 0.07 ± 0.07 logRAD (p2). CONCLUSIONS: Although optically the results are predictable, approximately 17% of the patients did not obtain objectively successful outcomes. In presbyopic patients without symptomatic cataracts, but with refractive errors, the PresbyMAX will decrease the presbyopic symptoms and correct far distance refraction in the same treatment, offering spectacle-free vision in daily life in most of the patients. Further investigation is necessary to evaluate the overall benefit of this procedure.
  American journal of ophthalmology 01/2013; · 3.83 Impact Factor
• Article: One-Year Experience in Presbyopia Correction With Biaspheric Multifocal Central Presbyopia Laser In Situ Keratomileusis.

  Michiel H A Luger, Tobias Ewering, Samuel Arba-Mosquera
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  ABSTRACT: PURPOSE:: To analyze simultaneous vision (distance and near) 1-year after biaspheric multifocal central presbyLASIK treatments for hyperopia and myopia with or without astigmatism. METHODS:: Patients were treated to correct distance ametropias and alleviating presbyopic symptoms simultaneously. All patients have been treated in Presby aberration-free mode using FemtoLASIK for Sphere from -7.00 to +3.25 diopters (D), astigmatism up to 3.00 D, and addition up to +2.75 D. No eye had previous corneal refractive surgery. Preoperative corneal curvature ranged between 40 and 48 D, with pachymetry thicker than 500 μm. Preoperative corrected distance visual acuity was 0.1 logarithm of the minimum angle of resolution (logMAR) or better, with near vision of 0.2 logRAD or better with addition up to +2.50 D. RESULTS:: Sixty-six eyes treated bilaterally using PresbyMAX software were reviewed. For 31 patients (94%), 1-year follow-up was completed. At 1 year, 70% of patients achieved uncorrected distance visual acuity 0.1 logMAR or better, 84% patients obtained uncorrected near visual acuity 0.1 logRAD or better, and 83% of eyes were within 0.75 D of defocus. Postoperative mean spherical equivalent refraction was -0.47 ± 0.44 D. Stability was achieved from the 6-week follow-up. Eighty-five percent of patients achieved simultaneously uncorrected distance visual acuity 0.2 logMAR or better and uncorrected near visual acuity 0.2 logRAD or better. CONCLUSION:: Patient selection and expectation management is essential to achieve patient satisfaction. Even though optically the results are predictable and good, some patients find it difficult to adapt to the compromise and others are dissatisfied by the minor loss of distance visual acuity. Certain individuals are best suited for PresbyMAX. A test with multifocal contact lenses or trial frames that creates slightly defocused images can be used to simulate postoperative visual impressions and verify patient acceptance.
  Cornea 10/2012; · 1.73 Impact Factor
• Article: Corneal Higher Order Aberrations After LASIK for High Myopia With a Fast Repetition Rate Excimer Laser, Optimized Ablation Profile, and Femtosecond Laser-assisted Flap.

  Alfredo Vega-Estrada, Jorge L Alió, Samuel Arba Mosquera, Luis J Moreno
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  ABSTRACT: To evaluate corneal higher order aberrations (HOAs) after LASIK for the correction of high myopia using a new generation of excimer laser (500-Hz repetition rate) and optimized ablation profiles. Retrospective consecutive study including 29 eyes from 17 patients (age range: 24 to 61 years) with high levels of myopia (spherical equivalent refraction ⩾8.50 diopters). All cases underwent LASIK using the sixth-generation Amaris (SCHWIND eye-tech-solutions) excimer laser and flap creation with the IntraLase (Abbott Medical Optics) femtosecond laser. Postoperative changes in corneal HOAs and corneal asphericity were analyzed during 6-month follow-up. Significant improvement in uncorrected distance visual acuity and spherical equivalent was observed (P<.01). Corrected distance visual acuity did not change after surgery (P=.37). Significant increases in corneal root-mean-square (RMS) HOA, RMS spherical aberration (SA), and RMS coma were observed 6 months after surgery (P<.01). Corneal asphericity for the 4.5-mm (Q45) and 8-mm (Q8) corneal diameter also increased significantly during the postoperative period (P<.01). Significant correlations were found between postoperative RMS HOA and RMS SA and RMS coma (r(2)=0.375, P=0.000 and r(2)=0.596, P=.000, respectively). Linear regression analysis showed a significant relationship between postoperative Q45 and preoperative pachymetry and treatment optical zone (R(2)=0.24, P<.05). A correlation was also found between postoperative Q8 and preoperative sphere and treatment ablation zone (R(2)=0.459, P<.006). A significant induction of corneal HOAs still exists with the latest generation Schwind excimer laser. Linear regression analysis will help predict postoperative asphericity obtained when using LASIK for the correction of high myopia.
  Journal of refractive surgery (Thorofare, N.J.: 1995) 10/2012; 28(10):689-96. · 2.54 Impact Factor