Open Access Case Report

Serratia marcescens Lacrimal Canaliculitis

Temitope Ewete, Adegboyega Sunday Alabi

Ophthalmology Research: An International Journal, Page 1-4
DOI: 10.9734/OR/2016/28205

Introduction: Serratia marcescens is a motile, facultatively anaerobic gram-negative rod of the Enterobacteriaceae family and has been implicated mostly in contact lens related keratitis. We report a case of lacrimal duct canaliculitis seen in an elderly patient with no known risk factors for Serratia marcescens infection.

Presentation of Case: 74-year-old woman presented with loss of vision in the left eye and decreased vision, purulent discharge, swelling and itching of the right eye. Examination revealed nasal upper and lower lid swelling of the left eye with copious foul smelling, purulent discharge with yellowish concretions. On the basis of these findings, an assessment of lacrimal gland canaliculitis was made and a sample of the discharge sent for microbiology, culture and sensitivity revealed Serratia marcescens as the causative organism. The patient was placed on topical and oral antibiotics and response was good.

Conclusion: This case reveals that Serratia marcescens, although a rare cause of ocular infections, cannot be ruled out as a cause of lacrimal canaliculitis in patients with no known risk factor. This reinforces the fact that microbiology, culture and sensitivity should be done in all cases of lacrimal gland infections.

 

Open Access Case study

Recurrent Radiation Retinopathy and Optic Neuropathy after Cranial Irradiation Therapy Treated by Intravitreal Bevacizumab

Serdar Ozates, Mert Simsek, Mehmet Citirik

Ophthalmology Research: An International Journal, Page 1-5
DOI: 10.9734/OR/2016/29856

Purpose: To report a case of radiation retinopathy and optic neuropathy after head irradiation therapy treated by intravitreal triamcinolone and bevacizumab

Methods: Case report.

Case: A 38 year old woman presented with visual acuity impairment. She received cranial radiation therapy (dose: 35Gy) for brain metastasis 1 year ago. The best-corrected visual acuity (BCVA) was 16/20 in the right and 4/20 in the left eye. Fundus examination showed hard exudate, retinal hemorrhage, and macular edema in both eyes. Triamcinolone acetonide was injected into the vitreous of both eyes. BCVA improved to 20/20 in the right and 12/20 in the left eye after 4 weeks. Both eyes showed recurrence of macular edema 3 months after the injection. BCVA was 2/20 in the right and 6/20 in the left eye.  Fundus examination showed retinal exudation and hemorrhage around the optic nerve and blurring of the optic nerve head borders was established. Three scheduled monthly injections of Bevacizumab were administered intravitrealy. After 3 injection, BCVA was 16/20 and 18/20 in her right and left eyes respectively.

Conclusion: Intravitreal bevacizumab was well tolerated, improved vision, and reduced retinal edema. No ocular or systemic side effects were noted.

 

Open Access Original Research Article

Combined Analysis of Safety and Optimal Efficacy in UV-light-activated Corneal Collagen Crosslinking

Jui-Teng Lin

Ophthalmology Research: An International Journal, Page 1-14
DOI: 10.9734/OR/2016/28712

Aims: To analyze the combined factors for safety and optimal efficacy for UV-light-initiated corneal collagen cross-linking (CXL).

Study Design: Modeling and analysis of CXL.

Place and Duration of Study: New Vision Inc, Taipei, between Oct. 2015 and July 2016.

Methodology: Analytic formulas were derived based on the coupled dynamic equations for the safety dose (E*), minimum corneal thickness and concentration of the riboflavin, and the cornea stiffness increase after the CXL. The critical parameters influencing the efficacy of CXL include: various absorption coefficients, initial concentration (C0) and diffusion depth (D) of the riboflavin solution, the quantum yield, the UV light intensity (I0) and dose (E), irradiation duration (t), the cytotoxic threshold dose of endothelial cells(E’) and the corneal thickness (z).

Conclusion: The safety dose (E*) is an increasing function of the parameter set (D, z, C0) and has a range of 5.3 to 10.1 J/cm2 for cytotoxicity threshold 0.63 to 1.26 J/cm2. Minimum corneal thickness z* =(300, 400) um for dose of E*=(5.0, 10.1) J/cm2 which has a much wider range than the conventional safety dose 5.4 J/cm2 (with z*=400 um). For maximum efficacy, the optimal dose is 0.7 to 1.55 J/cm2. However, to achieve crosslink depth of  230  to 300 um, higher dose of 2.0 to 3.0 J/cm2 is recommended.

 

Open Access Original Research Article

Gaussian Optics Analysis for Human Eyes with Application for Vision Corrections

Jui-Teng Lin

Ophthalmology Research: An International Journal, Page 1-5
DOI: 10.9734/OR/2016/28924

Aims: To derive formulae and analyze the roles of ocular components of human eye on the refractive power in various applications.

Study Design: Gaussian optics analysis.

Place and Duration of Study: Taipei, Taiwan, between May 2015 and August 2016.

Methodology: An effective eye model is introduced by the ocular components of human eye including refractive indexes, surface radius (r1, r2, R1, R2) and thickness (t,T) of the cornea and lens, the anterior chamber depth(S1) and the vitreous length (S2). Gaussian optics is used to calculate the change rate of refractive error per unit amount of ocular components of a human eye.

Results: For typical corneal and lens power of 42 and 21.9 diopters, the rate function defined by the change of refractive error (De) due to the change of ocular components, or Mj =dDe/dQj, with j=1 to 6 for Qj= r1, r2, R1, R2, t, T are calculated for a 1% change of Qj M1=+0.485, M2=-0.063, M3=+0.053, M4=+0.091, M5=+0.012,and M6=-0.021 diopters. For 1.0 mm increase of S1 and S2, the rate functions are: M7=+1.35, and M8=-2.67 diopter/mm.

Conclusion: Using Gaussian optics, we have derived analytic formulas for the change of refractive power due to various ocular parameter changes. These formulas provide the amount of refractive error corrections in various applications including laser in situ keratomileusis (LASIK) surgery and scleral ablation for accommodation.

 

Open Access Review Article

Role of Optical Coherence Tomography in Macular Disorders

Achyut N. Pandey, Amit Vikram Raina, P. D. Sharma

Ophthalmology Research: An International Journal, Page 1-11
DOI: 10.9734/OR/2016/27835

Optical coherence tomography (OCT) is an emerging technology for performing high-resolution cross-sectional imaging. OCT is analogous to ultrasound imaging, except that it uses light instead of sound. OCT can provide cross-sectional images of tissue structure on the micron scale in situ and in real time.

High resolution cross-sectional imaging of the retina is useful for identifying, monitoring and quantitatively assessing macular diseases. Optical coherence tomography (OCT) uses low coherence or white light interferometer to perform high resolution measurements and imaging. Optical coherence tomography (OCT) has a great potential as a diagnostic and research tool. However it has its own limitations in the presence of media opacities like vitreous hemorrhage, corneal edema and dense cataract. Hence, an attempt has been made to study the role of Optical coherence tomography in diagnosis of macular disorders.