Publications by authors named "Vincent C Fan"

6 Publications

  • Page 1 of 1

Changes in higher order wavefront aberrations after contact lens corneal refractive therapy and LASIK surgery.

J Refract Surg 2010 May 19;26(5):348-55. Epub 2010 May 19.

Department of Ophthalmology, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA.

Purpose: To compare ocular higher order aberrations induced by corneal refractive therapy (CRT, Paragon Vision) to those produced by LASIK for patients with comparable levels of myopia.

Methods: A retrospective chart review of 11 patients who used CRT lenses and 12 patients who underwent LASIK for correction of low to moderate myopia was performed. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, and optical higher order aberrations were recorded before and 1 month after treatment for each patient.

Results: The CRT group consisted of 11 patients (4 men, 7 women) with a mean age of 29.1+/-5.2 years (range: 23 to 40 years), and the LASIK group consisted of 12 patients (3 men, 9 women) with a mean age of 39.2+/-12.0 years (range: 23 to 60 years). Manifest refraction decreased statistically significantly from -2.81+/-1.05 diopters (D) at baseline to -0.77+/-0.64 D following CRT treatment at 1 month (P<.0001) and from -3.11+/-1.21 D at baseline to -0.43+/-0.27 D at 1 month after LASIK (P<.0001). Both CRT and LASIK exhibited no significant changes in total higher order aberrations for 4-mm pupils but induced statistically significant increases in total higher order aberrations for 6-mm pupils. Corneal refractive therapy and LASIK both exhibited statistically similar factors of change for total higher order aberrations and coma-like higher order aberrations for 6-mm pupils. Corneal refractive therapy demonstrated a statistically significant greater factor of increase in spherical-like higher order aberrations for 6-mm pupils (P=.01).

Conclusions: Contact lens corneal refractive therapy and LASIK can effectively correct myopia, but both increase higher order aberrations for 6-mm pupils to a similar degree. However, spherical-like aberrations were statistically significantly greater after CRT than after LASIK.
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http://dx.doi.org/10.3928/1081597X-20100218-03DOI Listing
May 2010

Evaluation of a new tear osmometer for repeatability and accuracy, using 0.5-microL (500-Nanoliter) samples.

Cornea 2009 Jul;28(6):677-80

Department of Ophthalmology, Mount Sinai School of Medicine, New York, NY 10029, USA.

Purpose: To evaluate the repeatability and accuracy of a new tear osmometer that measures the osmolality of 0.5-microL (500-nanoliter) samples.

Methods: Four standardized solutions were tested with 0.5-microL (500-nanoliter) samples for repeatability of measurements and comparability to standardized technique. Two known standard salt solutions (290 mOsm/kg H2O, 304 mOsm/kg H2O), a normal artificial tear matrix sample (306 mOsm/kg H2O), and an abnormal artificial tear matrix sample (336 mOsm/kg H2O) were repeatedly tested (n = 20 each) for osmolality with use of the Advanced Instruments Model 3100 Tear Osmometer (0.5-microL [500-nanoliter] sample size) and the FDA-approved Advanced Instruments Model 3D2 Clinical Osmometer (250-microL sample size).

Results: Four standard solutions were used, with osmolality values of 290, 304, 306, and 336 mOsm/kg H2O. The respective precision data, including the mean and standard deviation, were: 291.8 +/- 4.4, 305.6 +/- 2.4, 305.1 +/- 2.3, and 336.4 +/- 2.2 mOsm/kg H2O. The percent recoveries for the 290 mOsm/kg H2O standard solution, the 304 mOsm/kg H2O reference solution, the normal value-assigned 306 mOsm/kg H2O sample, and the abnormal value-assigned 336 mOsm/kg H2O sample were 100.3, 100.2, 99.8, and 100.3 mOsm/kg H2O, respectively.

Conclusions: The repeatability data are in accordance with data obtained on clinical osmometers with use of larger sample sizes. All 4 samples tested on the tear osmometer have osmolality values that correlate well to the clinical instrument method. The tear osmometer is a suitable instrument for testing the osmolality of microliter-sized samples, such as tears, and therefore may be useful in diagnosing, monitoring, and classifying tear abnormalities such as the severity of dry eye disease.
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http://dx.doi.org/10.1097/ICO.0b013e318198396bDOI Listing
July 2009

Fluorophotometry to evaluate the corneal epithelium in eyes undergoing contact lens corneal reshaping to correct myopia.

J Refract Surg 2009 04;25(4):366-70

Department of Ophthalmology, Mount Sinai School of Medicine, New York, NY10029, USA.

Purpose: To determine whether use of Corneal Refractive Therapy (CRT, Paragon Vision Sciences) lenses have an adverse effect on the health of corneal epithelium by monitoring epithelial permeability by fluorophotometry.

Methods: Eight patients with healthy eyes and whose refractive error was between -0.50 and -4.00 diopters (D) sphere and up to -1.75 D of astigmatism were enrolled. On the day of the fitting, two baseline fluorometric scans of the right eye were taken using the Ocumetrics Fluorotron Master. After 15 minutes, another two scans were taken of the right eye. The same fluorophotometry technique was repeated on day 1, 1 week, 1 month, and 3 months after the patient began overnight wear of the lenses. Patients' baseline corneal fluorescein levels and peak corneal fluorescence values after rinsing were compared to initial pre-fitting values to determine changes in corneal epithelial permeability.

Results: After patients used orthokeratology, uncorrected visual acuity was 20/20 or better in 9/16 eyes and 100% had achieved 20/40 or better by day 7. No adverse events were seen in patients utilizing orthokeratology, and eye examinations for these patients continued to be within normal limits. After nightly use of orthokeratology for 1 month, baseline fluorescence of the cornea (15.64 +/- 2.29 ng/mL vs 17.31 +/-5.43 ng/mL, P = .80) remained stable, and the post-15 minute scan peak corneal fluorescence values did not show significant changes from the pre-fitting (51.46 +/- 17.28 ng/mL) after use of orthokeratology (63.80 +/- 41.25 ng/mL) (P = .78).

Conclusions: Reshaping of the cornea through the use of orthokeratology does not have adverse effects on corneal epithelium as evaluated by changes in corneal epithelial permeability.
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http://dx.doi.org/10.3928/1081597X-20090401-12DOI Listing
April 2009

Contact lens-related Fusarium infection: case series experience in New York City and review of fungal keratitis.

Eye Contact Lens 2007 Nov;33(6 Pt 1):322-8

Department of Ophthalmology, Mount Sinai School of Medicine, 1190 Fifth Avenue, New York, NY 10029, USA.

Purpose: To report and define the clinical presentation, hygienic practices, treatment regimens, and visual sequelae of contact lens wearers infected with Fusarium keratitis in the New York City metropolitan area and to review the literature on Fusarium keratitis.

Methods: A retrospective chart review was conducted on three patients diagnosed with Fusarium keratitis by corneal fungal culture in the New York City metropolitan area from October 2005 to February 2006. None of the patients had a history of recent ocular trauma before infection.

Results: All three patients used disposable soft contact lenses and ReNu with MoistureLoc 1 month before infection. All patients experienced a unilateral stabbing pain of the affected eye after removal of the contact lens. Patients had corneal ulcers ranging from 1 to 5 mm in diameter and were all initially treated with topical antibiotics and steroids for a period between 7 and 52 days. Antifungal treatment was eventually prescribed to all patients, with topical natamycin 5% every hour being the most common. One patient required corneal transplantation, and the other two patients recovered visual acuity comparable to their baseline acuity.

Conclusions: A delay in diagnosis and prolonged treatment delay of Fusarium keratitis is associated with significant comorbidity. Physicians must have a higher index of suspicion for fungal keratitis in contact lens wearers to facilitate in early diagnosis and treatment.
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http://dx.doi.org/10.1097/ICL.0b013e3180645d17DOI Listing
November 2007

Conductive keratoplasty.

Curr Opin Ophthalmol 2007 Jul;18(4):334-7

Department of Ophthalmology, Mount Sinai School of Medicine, New York, NY 10029, USA.

Purpose Of Review: Conductive keratoplasty is a noninvasive, in-office procedure for the correction of hyperopia, hyperopic astigmatism, and management of presbyopia. It serves as an alternative to laser-based refractive surgery with essentially no intraoperative or postoperative complications.

Recent Findings: In the past decade, photorefractive keratectomy and laser in-situ keratomileusis have been the most popular refractive surgical procedures to correct myopia, hyperopia and astigmatism. Although relatively safe, flap-related complications often result in undesirable visual acuity. Since US Food and Drugs Administration approval in 2002, conductive keratoplasty has become a promising technique to correct low to moderate hyperopia and astigmatism. The procedure was first used by Mendez and colleagues in 1993. It is a nonlaser, no cutting procedure that delivers radio-frequency energy to corneal stroma in a circular fashion to steepen the cornea. Multiple studies have shown that conductive keratoplasty offers equal or superior efficacy, predictability, stability and safety than currently used refractive procedures to correct hyperopia or hyperopic astigmatism. In addition, monovision conductive keratoplasty has been shown to be successful for the management of presbyopia.

Summary: Conductive keratoplasty, an alternative to the laser-based procedure, is effective, predictable, and safe to correct low to moderate hyperopia, astigmatism, and manage presbyopia.
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http://dx.doi.org/10.1097/ICU.0b013e3281df2cf0DOI Listing
July 2007

Fluorophotometry as a diagnostic tool for the evaluation of dry eye disease.

BMC Ophthalmol 2006 May 26;6:20. Epub 2006 May 26.

Department of Ophthalmology, Mount Sinai School of Medicine, New York, NY, USA.

Background: Dry eye disease is a common debilitating ocular disease. Current diagnostic tests used in dry eye disease are often neither sensitive nor reproducible, making it difficult to accurately diagnose and determine end points for clinical trials, or evaluate the usefulness of different medications in the treatment of dry eye disease. The recently developed fluorophotometer can objectively detect changes in the corneal epithelium by quantitatively measuring its barrier function or permeability. The purpose of the study is to investigate the use of corneal fluorescein penetration measured by the fluorophotometer as a diagnostic tool in the evaluation of dry eye patients.

Methods: Dry eye patients (16 eyes), who presented with a chief complaint of ocular irritation corresponding with dry eye, low Schirmer's one test (<10 mm after 5 minutes) and corneal fluorescein staining score of more than two, were included in the study. Normal subjects (16 eyes), who came for refraction error evaluation, served as controls. Institutional Review Board (IRB) approved consent was obtained before enrolling the subjects in the study and all questions were answered while explaining the risks, benefits and alternatives. All Fluorophotometry of the central corneal epithelium was done utilizing the Fluorotron Master. Each eye had a baseline fluorescein scan performed, after which 50 l of 1% sodium fluorescein dye was instilled. Three minutes later, the fluorescein was washed with 50 ml of normal saline. Fluorescein scans were then started immediately after washing and were recorded at 10, 20, 40, and 60 minutes thereafter. The corneal peak values of fluorescein concentration were recorded within the central cornea in both dry eyes and in controls.

Results: Ten minutes after fluorescein installation, patients with dry eye disease averaged a five-fold increase in corneal tissue fluorescein concentration (mean = 375.26 +/- 202.67 ng/ml) compared with that of normal subjects (mean = 128.19 +/- 85.84 ng/ml). Sixty minutes after dye installation, patients with dry eye disease still revealed higher corneal tissue fluorescein concentration (mean = 112.87 +/- 52.83 ng/ml) compared with that of controls (mean = 40.64 +/- 7.96 ng/ml), averaging a three-fold increase.

Conclusion: Patients with dry eye disease demonstrated an increased corneal permeability and a slower rate of elimination to topically administered fluorescein when measured by the fluorophotometer. This suggests that fluorophotometry may serve as a valuable quantitative and objective tool for the diagnosis of dry eye disease, and in following patients' response to new treatment modalities. Fluorophotometry may serve as an objective non-invasive tool for end-point analysis in clinical trials of new treatments for dry eye disease.
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http://dx.doi.org/10.1186/1471-2415-6-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1523366PMC
May 2006
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