Winai Chaidaroon

Normative database of retinal nerve fiber layer and macular retinal thickness in a Thai population

PurposeTo investigate the distribution of retinal nerve fiber layer (RNFL) and macular retinal thickness measured by optical coherence tomography (OCT) in a Thai population.MethodsWe studied one eye each of 250 healthy subjects [age ≥ 18 years; spherical refractive error within ±6 diopters (D); astigmatism ≤3 D; no ocular pathology]. A complete eye examination, standard automated perimetry, and fast RNFL and macular thickness measurement by OCT were performed, and a disc photograph was taken. The distributions of both thicknesses, including their relationship with demographic data, were analyzed.ResultsThe mean ± SD age of the study population was 44.7 ± 12.2 years. The mean ± SD RNFL thickness was 109.3 ± 10.5 m, which was 10% thicker than that in the OCT normative database. RNFL decreased 2.3 m per decade (P < 0.001). Sex and spherical equivalent were not associated with RNFL thinning. The mean ± SD central foveal thickness was 183.2 ± 1.3 m. The macular thickness in the outer area was significantly thinner than that in the inner area (P < 0.001). The temporal regions were the thinnest among the four quadrants (P < 0.001). Thinning of all macular areas, except the center, was found to be associated with advancing age (P < 0.05).ConclusionsRNFL thickness in the measured Thai population was about 10% thicker than that in the original normative database. Macular thickness and RNFL thickness in the superior and inferior quadrants decreased with advancing age.

Colvard pupillometer measurement of scotopic pupil diameter in emmetropes and myopes

PURPOSE To prospectively compare the scotopic pupil size between emmetropes and myopes using a Colvard pupillometer. METHODS The pupil diameters of 55 normal subjects and 55 healthy myopic subjects were measured with the Colvard pupillometer in a low-light situation that simulated the level of light encountered while driving at night. RESULTS The mean (+/- SD) age of the emmetropic subjects was 30.78 years +/- 10.03 (range, 18-54 years) and the mean (+/- SD) age of the myopic subjects was 27.35 years +/- 8.43 (range, 21-52 years). The mean (+/- SD) scotopic pupil diameter was 6.46 +/- 0.90 mm (range, 4.5-8.0 mm) in the emmetropic group and 6.98 +/- 0.67 mm (5.5-8.5 mm) in the myopic group. The unpaired Student t-test showed that the difference in the scotopic pupil diameter between emmetropes and myopes was statistically significant (P =.0001). CONCLUSIONS The mean scotopic pupil diameter in myopes was larger than that in emmetropes. Therefore, a large ablation zone of the cornea or an appropriate optical size of the phakic intraocular lens should be considered in refractive surgery. Preoperative scotopic pupil measurements may be necessary in all refractive patients.

Nocardia keratitis in a human immunodeficiency virus patient

BackgroundThe development of Nocardia keratitis in a patient with human immunodeficiency virus infection is rare, and we could find no cases reported in the literature.CaseA 48-year-old woman who had human immunodeficiency virus infection presented with decreased visual acuity, redness, and irritation in the right eye.ObservationsInitially, the diagnosis was fungal keratitis, and she was treated with 0.3% amphotericin B eye drops and oral fluconazole for 1 month without improvement. Then, all former drugs were discontinued, and a corneal scraping was carried out. The culture result disclosed Nocardia asteroides, and after treatment with 10% sulfacetamide eye drops and oral trimethoprim-sulfamethoxazole, the keratitis subsided dramatically.ConclusionsThe treatment result for Nocardia keratitis in a human immunodeficiency virus patient was favorable after intensive use of 10% sulfacetamide eyedrops. Nocardia keratitis should be kept in mind as a possible causative organism when antifungal therapy fails in a keratitis case.

Ocular Bacterial Flora in HIV-Positive Patients and Their Sensitivity to Gentamicin

Normal ocular flora comprise a heterogenous collection of bacteria. The natural immunity, natural resistance, and specific immunologic phenomena that regulate them derive from the host and microbes. However, the natural defense is a combination of innate immunity and specific acquired immunity. Acquired immunodeficiency syndrome (AIDS) is caused by infection with the human immunodeficiency virus (HIV). This retrovirus infects and destroys T-helper cells, resulting in a profound deficiency of natural immunity. The purpose of this study was to investigate the ocular bacterial flora of patients who had HIV infection and their sensitivity to gentamicin.

Outcomes of LASIK for Myopia or Myopic Astigmatism Correction with the FS200 Femtosecond Laser and EX500 Excimer Laser Platform

Purpose: To evaluate the efficacy, predictability, stability and safety of laser in situ keratomileusis (LASIK) using the FS200 femtosecond laser and EX500 excimer laser platform. Methods: The outcomes of 254 eyes of 129 consecutive patients with myopia or myopic astigmatism who underwent full correction femtosecond laser-assisted LASIK at CMU LASIK Center were assessed. Pre-operative and post-operative parameters including manifest refraction, Uncorrected Distance Visual Acuity (UDVA), Best Corrected Distance Visual Acuity (BDVA), corneal topography and tomography were analyzed. The results between low to moderate myopia and high myopia were compared up to 12 months. Results: Mean pre-operative Spherical Equivalent (SE) was -5.15±2.41 Diopters (D) (range -0.50 to -11.50 D) and -0.13±0.28 D, -0.13±0.27 D, -0.13±0.28 D and -0.14±0.30 D at 1, 3, 6, and 12 months, post-operatively. At 12 months, the propor¬tion of eyes achieving UDVA ≥ 20/20 was 90.0% and ≥20/40 was 98.8%. The proportion of eyes achieving post-operative mean SE ±0.5 D, and ±1 D was 91.3%, and 98.5%. No eyes lost more than two lines of BDVA. The low to moderate myopic group had a statistically significant better UDVA at one (p=0.017) and three months (p=0.014) but no difference at six (p=0.061) and 12 months (p=0.091). The mean post-operative SE was better in low to moderate myopic group at every follow-up visit (p=0.001, 0.007, <0.001 and <0.001). Conclusion: One-year clinical results of LASIK with the FS200 femtosecond laser and EX500 excimer laser showed high efficacy, predictability, stability and safety.

Pseudomonas Scleritis following Pterygium Excision

Purpose: The aim of this case report was to describe a patient who presented with Pseudomonas scleritis after pterygium excision. The study was conducted at the Department of Ophthalmology, Faculty of Medicine, Chiang Mai University in Chiang Mai, Thailand. Methods: The record of a patient who was diagnosed as Pseudomonas scleritis after pterygium excision was retrospectively reviewed for history, clinical characteristics, laboratory findings, treatments, and outcomes. Results: We described a 66-year-old male patient with a history of pterygium excision in his right eye 10 years ago, he presented with infectious scleritis. Scleral thinning, tissue necrosis, and overlying calcified plaque were found. The culture of scleral scraping revealed Pseudomonas aeruginosa. Topical fortified amikacin (20 mg/mL) and intravenous ceftazidime were started. Urgent surgical debridement of scleral infiltrates and irrigation of necrotic sclera and surrounding conjunctiva with fortified amikacin (20 mg/mL) were performed. After 2 weeks of treatment, scleral thinning and inflammation decreased, and the best-corrected visual acuity improved from 6/24 to 6/9. Fortified amikacin eye drops (20 mg/mL) were continued until the fourth week, with no scleral thinning seen. Conclusions: P. aeruginosa is a virulent organism that causes infectious scleritis complicated by melting and necrotizing of the sclera. This report emphasized that early recognition, intensive antimicrobial treatment, and surgical debridement can prevent morbidity related to this Pseudomonas infection.

Corneal Phaeohyphomycosis Caused by Bipolaris hawaiiensis

Purpose: To report a rare case of keratitis infected by Bipolaris hawaiiensis. Methods: A patient who was diagnosed as fungal keratitis caused by B. hawaiiensis was retrospectively reviewed for history, clinical characteristics, risk factors, laboratory findings, treatments, and outcomes. Results: A 63-year-old man with a history of trauma and saw dust in the left eye presented with a corneal ulcer. Eye examination revealed whitish infiltration with a feathery edge and small brownish deposits in the anterior stroma of the left cornea. Numerous septate hyphal fragments were detected in a corneal specimen, and nucleotide sequence analysis identified B. hawaiiensis. Treatment was started with 5% natamycin eyedrops and oral itraconazole. Subsequently, a corneal plaque developed which did not respond to medication and debridement. The patient underwent therapeutic penetrating keratoplasty. Conclusions: B. hawaiiensis is a rare cause of corneal phaeohyphomycosis. A brownish pigmented infiltration is an important diagnostic clue, however microbiologic studies are required to obtain a definite diagnosis. Although antifungal medication and debridement are the mainstay of most corneal fungal infection, therapeutic penetrating keratoplasty can prevent morbidity related to this fungal infection.

Corneal Ring Infiltrates Caused by Serratia marcescens in a Patient with Human Immunodeficiency Virus

Purpose: To describe corneal ring infiltrates caused by Serratia marcescens in a patient with human immunodeficiency virus (HIV-1) who wore contact lenses. Methods: A case study of a patient with keratitis due to an infection caused by S. marcescens and exhibiting corneal ring infiltrates was reviewed for history, clinical manifestation, microscopic study, and management. Results: A 29-year-old man who had a history of contact lens wear and HIV-1 infection was admitted to hospital because of blurred vision, redness, and corneal infiltrates in the shape of a ring in the left eye. The visual acuity (VA) in both eyes was hand movement (uncorrected). Corneal scrapings were performed. The culture results of the corneal specimens revealed S. marcescens. The culture results of the contact lens disclosed the same organism. The corneal ulcer responded well to treatment with topical gentamycin sulfate 14 mg/ml. The final VA remained hand movement. Conclusions: S. marcescens can cause ring infiltrates in a HIV-1 patient who wears contact lenses. The treatment result for S. marcescens keratitis in a HIV-1 patient who wore contact lenses was favorable after intensive use of fortified topical antibiotics.

Corneal Chromoblastomycosis Caused by Fonsecaea pedrosoi

Purpose: To report 2 unusual cases of fungal keratitis due to Fonsecaea pedrosoi. Methods: Two patients were diagnosed with Fonsecaea pedrosoi keratitis. Their files were reviewed for predisposing factors, clinical characteristics, microbiological study, treatment, and outcome. Results: Two consecutive patients presented with brownish pigmented corneal ulcers in their eyes after sustaining eye trauma from vegetative matter. In both cases, corneal scrapings were collected for microscopic examination and culture. Dematiaceous hyphae were seen on the smears, and dark pigmented colonies grew on the culture media, identified as F. pedrosoi. Both patients were treated and cured with combined topical antifungal agents and oral itraconazole. The first patient required an amniotic membrane patch, while the second received an intracameral amphotericin B injection. Conclusions: Pigmented infiltrates can be an important diagnostic clue, but a microscopic evaluation and culture are required to obtain an accurate diagnosis of Fonsecaea keratitis. The prompt diagnosis and combined antifungal treatment can prevent morbidity associated with this fungal infection.

Bat attack! : an unusual cause of keratouveitis

Dear Editor, Eye injury from flying bats are extremely rare, as they have a special ultrasonic echolation system which they use instead of sight to guide their way [1]. This complex system enables them to avoid any obstacles when gliding at high velocities, even in complete darkness. There has been one other report of corneal perforation from collision with a bat [2]. Here we report a case of a bat attack with a corneal foreign body which was a part of the bat’s claw, resulting in localized keratitis and anterior uveitis, a finding which has not been previously described.