Effect of eye laterality on correction of myopic astigmatism with small incision lenticule extraction (SMILE) using vector analysis.

PURPOSE: To compare the vector analysis, visual, and refractive outcomes after myopic astigmatic correction using SMILE between the right and left eyes. METHODS: This is a retrospective study including 41 right and 40 left eyes that underwent SMILE for correction of myopic astigmatism greater than 0.75 diopters (D) with a follow-up of at least 3 months. Vector analysis for astigmatic correction was done. Visual and refractive parameters were compared between both groups by measuring mean postoperative logMAR uncorrected distance visual acuity, mean postoperative spherical equivalent (SE), cylinder, and refractive predictability in terms of SE and cylindrical correction. Efficacy and safety of SMILE were also determined. RESULTS: No significant difference was found between vector outcomes except for angle of error (AE). The right eye group yielded a negative mean AE (- 2.71 ± 5.35), while the left eye group yielded a positive mean AE (0.23 ± 9.60). Correction index, magnitude of error and refractive predictability of cylindrical correction showed undercorrection of astigmatism in both groups. The right eye group showed lower predictability for higher cylindrical correction. Visual outcomes were similar for both eyes. CONCLUSION: Rotational errors account for vectorial outcome differences between right and left eyes. Despite achieving good visual and refractive outcomes with low cylinder correction, the tendency to undercorrect between eyes due to this error may be more evident when treating higher amounts of astigmatism. More careful preoperative control for cyclotorsion is warranted for right eyes compared to left eyes.

Comparative study between fibrin glue prepared from a single human donor and sutures for sealing induced corneal penetrating wounds on porcine eyes

@#<p style="text-align: justify;"><strong>OBJECTIVE:</strong> To determine the efficacy of fibrin glue derived from a single human donor for sealing induced penetrating corneal wounds on cadaveric porcine eyes compared to conventional suturing.</p> <p style="text-align: justify;"><strong>METHODS:</strong> Forty (40) porcine eyes were randomized into two groups. In the experimental group, the corneal incisions were sealed using fibrin glue prepared from a single human donor. Eyes in the control group were sealed using two interrupted nylon 10-0 sutures. Baseline intraocular pressures were obtained and an anterior chamber maintainer connected to the Centurion Vision System was inserted through a side port. A 3 mm metal keratome was used to create a uniform, central, full-thickness straight incision in all eyes. After making the incision, the presence or absence of leakage was determined using Seidel's test. The eyes were then sealed according to the group they were randomized in. The intraocular pressure (IOP) was gradually increased using the Centurion Vision System to determine the leakage pressure of all sealed eyes in both groups.</p> <p style="text-align: justify;"><strong>RESULTS:</strong> The mean baseline IOP was comparable between the two groups (control group = 21.15 + 1.66 mmHg; experimental group = 21.65 + 1.81, p value = 0.299). All eyes in the control group, showed no leakage immediately after sealing the corneal wounds with sutures. One out of twenty eyes in the experimental group was positive for leakage after application of the fibrin glue (p value = 0.5). The mean leakage pressure was significantly higher for the suture group at 90.25 + 14.9 mmHg compared to the fibrin glue group at 32.30 + 7.6 mmHg (p value = <0.001).</p> <p style="text-align: justify;"><strong>CONCLUSION:</strong> Fibrin glue prepared from a single donor is comparable to two nylon 10-0 sutures in sealing 3 mm corneal penetrating wounds at IOP of up to 32 mmHg. For higher IOP, nylon 10-0 suture is more effective than fibrin glue in sealing the corneal penetrating wounds in cadaveric porcine eyes. </p>

Comparison of Small Incision Lenticule Extraction (SMILE) and Femtosecond Laser In-Situ Keratomileusis (F-LASIK) for the correction of myopia and astigmatism: 1-year clinical outcome

@#<p style="text-align: justify;"><strong>OBJECTIVE:</strong> To compare the efficacy, refractive predictability, stability and safety of Small Incision Lenticule Extraction (SMILE) and Femtosecond Laser In-Situ Keratomileusis (F-LASIK) for the correction of myopia and astigmatism.</p> <p style="text-align: justify;"><strong>METHOD:</strong> This study was approved by the Institutional Review Committee of the St. Luke's Medical Center. A retrospective chart review was conducted at the Vision Laser Center of the St. Luke's Medical Center-Global City. All patients that underwent SMILE from January 2014 to July 2014, with adequate follow-up at 1 day, 1 week, 1 month, 3 months and 1 year, were included in the study. Age-matched and refraction-matched patients, who underwent F-LASIK from January 2012 to April 2014, were chosen as comparators. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), attempted refraction versus achieved refraction and adverse events at 1 day, 1 week, 1 month, 3 months and 1 year were compared postoperatively in both groups. Primary outcome measures were efficacy expressed as the percentage of eyes achieving UCVA of 20/25 or better during the postoperative follow-up, refractive predictability, safety and stability. </p> <p style="text-align: justify;"><strong>RESULTS:</strong> Thirty-five eyes of 18 patients who underwent SMILE and 38 eyes of 19 patients who underwent FLASIK were included in the study. The mean preoperative spherical equivalent of both groups had no statistical difference, with -3.84 ± 1.31 D and -4.07 ± 1.39 D for SMILE and F-LASIK, respectively (p=0.801). At 1 week postoperatively, 51% and 97% achieved UCVA of 20/25 or better in the SMILE and F-LASIK groups. At 3 months, 97% had 20/25 vision or better for the SMILE group, while 100% had 20/25 vision or better for the F-LASIK group. At 1 year, both groups achieved 100% 20/25 or better vision. Three percent lost one line of BCVA in both groups at 1 year. Mean spherical equivalent (SE) between groups at 1 year showed no statistically significant difference (p=0.21), with 0.05 ± 0.18 D in the SMILE group and -0.1 ± 0.15 D in the F-LASIK group. No significant change in mean SE was observed within groups from 1 day to 1 year post op, p=0.166 for SMILE and p=0.226 for F-LASIK. At 1 year, 100% of the SMILE and F-LASIK groups were within ± 0.5 D of target refraction. No adverse events were noted in either group. </p> <p style="text-align: justify;"><strong>CONCLUSION:</strong> SMILE was comparable to F-LASIK in terms of visual outcomes (efficacy, refractive predictability, stability) and safety for the treatment of myopia and astigmatism. However, a slight delay in visual improvement during the first week was observed in the SMILE group.</p>

Isolation of acanthamoeba genotype t4 from a non-contact lens wearer from the Philippines.

We report the case of a 76-year old Filipino male who presented with pain, redness, and blurring of vision of the right eye. Corneal scraping was done and sent to the St. Luke's Research and Biotechnology Group for detection and identification of the infectious agent. Morphological detection was performed by allowing the organism from the scraping to grow in 1.5% non-nutrient agar plate with heat-killed E. coli. Trophozoites with acanthopodia and double-walled cysts characteristic of Acanthamoeba were observed within the first and second week of observations, respectively. Molecular identification of the amoebae at the genus level based on the presence of Acanthamoeba-specific amplimer S1, ASA.S1 confirmed the morphological identification. Genotyping through sequence revealed that the organism belonged to T4, which is the genotype commonly present in the eye of keratitis patients.

Determining corneal power using Orbscan II videokeratography for intraocular lens calculation after excimer laser surgery for myopia.

PURPOSE: To assess the accuracy of Orbscan II slit-scanning videokeratography for intraocular lens (IOL) calculation in eyes with previous photorefractive surgery for myopia. SETTING: Private practice, St. Louis, Missouri, USA. METHODS: Corneal power (K) was measured by manual keratometry, Placido-based videokeratography (Atlas), slit-scanning videokeratography (Orbscan II), and contact lens overrefraction in 21 post-photoablation eyes having cataract surgery. Postoperative data collected after phacoemulsification were used to back-calculate corneal power (BCK). The BCK values were statistically compared at 3.0 to 6.0 mm central Orbscan II curvature and power measurements, including total axial power, total tangential power, total mean power, and total optical power. Similar comparisons were made to Atlas curvature at the 0.0 to 10.0 mm zones. RESULTS: The mean corneal power after refractive surgery based on BCK values using the Holladay 2 formula (BCK H2) was 39.35 diopters (D) +/- 2.58 (SD). The mean manual value (40.52 +/- 1.95 D) and Atlas-based values were statistically higher than BCK H2 values (P<.001). The mean corneal power calculated from historical data was 39.33 +/- 2.70 D (P = .83 to BCK H2; n = 19) and from contact lens overrefraction, 41.38 +/- 3.11 D (P = .19; n = 5). Orbscan II parameters (n = 21) of the total mean power (3.0 mm, 39.10 +/- 2.63 D), total tangential power (3.0 mm, 39.11 +/- 2.60), total axial power (5.0 mm, 39.19 +/- 2.55 D), and total optical power (3.0 mm, 39.08 +/- 2.78 D; 4.0 mm, 39.39 +/- 2.76 D) were statistically similar to both the historical and BCK H2 values (P>.11). If used prospectively, 80.9% of eyes would have been within +/-0.50 D of the targeted refraction using a 4.0 mm total optical power, 76.2% using a 5.0 mm total axial power, and 42.1% using the historical method. CONCLUSION: The Orbscan II 5.0 mm total axial power and 4.0 mm total optical power can be used to more accurately predict true corneal power than the history-based method and may be particularly useful when pre-LASIK data are unavailable.

Retained contact lens for more than 10 years in a laser in situ keratomileusis patient.

A 49-year-old man with blurred vision in 1 eye and myopic regression had laser in situ keratomileusis (LASIK) in the right eye after having 20/20 uncorrected visual acuity for 2 years. At the conclusion of surgery, a poly(methyl methacrylate) contact lens that had been retained for more than 10 years was discovered in the upper fornix. Although the patient remained asymptomatic, reports of significant complications associated with retained contact lenses are numerous. In addition, retained contact lenses, lid lesions, and periocular masses can induce refractive and topographic changes after LASIK. The retained contact lens may have led to compression-induced changes in corneal curvature, resulting in the need for uniocular enhancement 2 years after the primary LASIK procedure.

Intraocular lens calculations in patients with corneal scarring and irregular astigmatism.

PURPOSE: To compare various methods of estimating corneal power for intraocular lens (IOL) calculation in patients with irregular corneal astigmatism. SETTING: Pepose Vision Institute, St. Louis, Missouri, USA. Case reports and review of the medical literature. RESULTS: Two patients with irregular corneal astigmatism had an IOL exchange after a "surprise" post-cataract-surgery refraction. In the first case, the patient had a post-cataract-surgery refraction of +5.50 -0.75 x 69 and in the second case, a refraction of -7.00 -1.00 x 180. The central corneal power before IOL exchange was assessed using manual keratometry, various computerized videokeratography curvature and power maps, and contact lens overrefraction. The total axial power map (Orbscan(R), Bausch & Lomb), total optical power map (Orbscan), and contact lens overrefraction method provided the most accurate estimates of central corneal power in these 2 patients. CONCLUSION: Computerized scanning-slit videokeratography, which analyzes the anterior and posterior surfaces of the cornea, and the contact lens overrefraction method gave good estimations of corneal power in patients with irregular corneal astigmatism. This type of analysis may improve the accuracy of IOL calculation in patients with corneal pathology and irregular astigmatism.

Proper positioning of the plume evacuator in the VISX Star3 excimer laser minimizes central island formation in patients undergoing laser in situ keratomileusis.

PURPOSE: To identify risk factors in a series of patients who developed steep central islands after laser in situ keratomileusis (LASIK). METHODS: We analyzed and compared the refractive and topographic outcome of a study group composed of 83 eyes of 44 patients who underwent LASIK using the VISX Star3 excimer laser with a refraction-matched control group of 83 eyes treated later. The vacuum aspirator of the excimer laser was abnormally positioned during the surgeries performed in the study group. RESULTS: Mean preoperative spherical equivalent refraction in the study group was -6.75 +/- 2.50 D. Four eyes with a mean preoperative spherical equivalent refraction of -9.27 +/- 2.29 D developed steep central islands. Thirty-three (38%) of 83 eyes treated needed retreatment for residual myopia or myopic astigmatism. In the control group, mean preoperative spherical equivalent refraction was -6.76 +/- 2.50 D. Ninety-three percent of eyes were within +/- 1.00 D of target refraction. Five (6.02%) of 83 eyes required retreatment and no eyes developed central islands. CONCLUSION: The abnormally positioned vacuum aspirator coupled with the higher preoperative refractive correction were the likely causative factors for central island formation and the increased incidence of undercorrection in these patients.

Late corneal scarring after photorefractive keratectomy concurrent with development of systemic lupus erythematosus.

PURPOSE: To report a case of late-onset corneal haze following previous photorefractive keratectomy (PRK) concurrent with the development of systemic lupus erythematosus. METHODS: Single case report and review of medical literature. RESULTS: A 41-year-old woman underwent uneventful bilateral, non-simultaneous photorefractive keratectomy (PRK) with retreatment of the right eye after 1 year. Two months after retreatment, the patient presented with headaches and mental status changes and was diagnosed with systemic lupus erythematosus. Severe reticular corneal scarring developed in the right eye 1 year after retreatment. After the patient's disease was well controlled on a maintenance dose of hydroxychloroquine 200 mg twice a day, mechanical debridement was performed on the right cornea with a marked decrease in corneal haze and improved best spectacle-corrected vision. CONCLUSION: Patients who manifest with autoimmune disorders such as systemic lupus erythematosus may be at greater risk for developing dense, reticular corneal scars after PRK.