Epithelium-on photorefractive intrastromal cross-linking (PiXL) for reduction of low myopia.

PURPOSE: To report the 9-12-month outcomes of a novel procedure for reduction of low myopia through epithelium-on photorefractive intrastromal cross-linking (PiXL) with customized control of topographic distribution of ultraviolet (UV)-fluence. METHOD: Myopic patients with normal (non-ectatic) corneas underwent the PiXL procedure for reduction of low myopia. PiXL treatments were delivered through selective application of UVA light based on the refractive error of each patient. Clinical evaluation included safety (corrected distance visual acuity, endothelial cell count, central corneal thickness, anterior ocular health) and efficacy (uncorrected distance visual acuity, manifest refraction, K-mean) examinations. In addition, a patient satisfaction survey was conducted at 9 months post-procedure to evaluate patients' subjective experience with the procedure. RESULTS: Fourteen myopic eyes (mean manifest refraction spherical equivalent -1.62±0.6D; range -0.75 to -2.65D) of 8 subjects (mean age 30 years old; range 24-51 years old) were enrolled in the study. At 12 months post-procedure, a mean manifest refraction spherical equivalent reduction of 0.72±0.43D (P<0.001) was observed, with a corresponding gain in uncorrected visual acuity of 0.25 logMAR and mean K-mean flattening of 0.47±0.46D. All patients achieved best corrected visual acuity of 20/20 or better from 1 month onward. There were no cases of ocular infection or secondary changes to the crystalline lens and retina due to UV exposure, while transient corneal haze subsided gradually. CONCLUSION: The epithelium-on PiXL procedure was safe and effective in reducing myopic refractive error in this study with up to 12 months follow-up. Early results of this novel application of collagen cross-linking are encouraging but longer-term data in larger studies are required. PRECIS: This paper serves to introduce and report the early clinical results of epithelium-on PiXL, a novel application of cornea cross-linking, in reducing low myopia in Asian eyes, which are under-represented in studies of similar design.

Facial Scanning With a Digital Camera: A Novel Way of Screening for Primary Angle Closure.

PURPOSE: We hypothesize that patients with primary angle closure (PAC) have common significant facial characteristics that set them apart from an age-matched, sex-matched, and race-matched control population. The primary objective of this study was to test whether a 3-dimensional (3D) camera could pick up these differences in order to differentiate PAC patients from controls. PATIENTS: A total of 55 patients with PAC and 38 controls were included in the study. MATERIALS AND METHODS: Cases and controls had their facial photographs taken using a 3-dimensional digital camera (3dMdFace System). The facial features in the captured photographs were analyzed using a computer software (Neural Network Toolbox). A regression formula was devised to show whether these facial parameters could be used to distinguish between patients and controls. RESULTS: Thirteen facial parameters were measured, and using a regression formula and neural network classification we were able to mathematically distinguish patients from controls using this method of screening. CONCLUSIONS: PAC patients have distinct facial features that may be differentiated from those of normal individuals mathematically using 3D photography. There is potential for this 3D facial scanning technology in screening for PAC in the general population.

Mitochondrial Changes in Aging Orbicularis Oculi Muscles: Histologic and Genetic Analyses in Elderly Asian Patients.

PURPOSE: We aimed to determine whether there was underlying mitochondrial myopathy in some aging patients diagnosed with involutional ptosis. We compared orbicularis oculi muscle from patients with ptosis and patients with dermatochalasis without ptosis, using histochemical and mitochondrial DNA (mtDNA) analysis. DESIGN: This was a case-control study. METHODS: We studied 10 patients with ptosis who underwent correction surgery, and 10 patients without ptosis, who had dermatochalasis surgery, all in 1 institution. Orbicularis oculi muscle was examined with standard muscle histochemistry; modified Gomori trichrome, nicotinamide adenine dinucleotide (NADH), succinyl dehydrogenase (SDH), cytochrome c oxidase (COX), and Congo red. Genetic analysis was performed for deletions of mtDNA. RESULTS: The mean age of the group with ptosis was 67.6 years and that of the dermatochalasis group was 65.2 years. Inflammation, fibrosis, or amyloid was not present in the orbicularis of either ptosis or dermatochalasis group. There was no significant difference in ragged red fibers, NADH, SDH, or COX staining patterns between ptosis and dermatochalasis groups. One of 10 specimens in the ptosis group and 1 of 10 in the dermatochalasis group showed deletion of mtDNA. CONCLUSIONS: Our study of orbicularis oculi muscle found no difference between patients with and without involutional ptosis. We conclude that the presence of ragged red fibers, subsarcolemmal NADH and SDH accentuation, and COX-negative staining patterns in orbicularis muscle could represent age-related involutional changes. The significance of deletion of mtDNA needs further investigation.

Rosiglitazone toxicity: accidental overdose leading to macular edema.

BACKGROUND/PURPOSE: To highlight the clinical effects of rosiglitazone overdose. METHODS: Case report, observational. RESULTS: A 60-year-old Chinese man accidentally ingested 20 mg rosiglitazone. His usual dose was 2 mg once in the morning. Complications of drug overdose were monitored. He consequently developed right mild macular edema. This resolved spontaneously without laser treatment. No systemic toxicity, hypoglycemia, or peripheral edema was observed. CONCLUSION: Rosiglitazone overdose causes acute macular edema that resolves spontaneously.

Lens Opacities Classification System III: cataract grading variability between junior and senior staff at a Singapore hospital.

PURPOSE: To test the reliability of the Lens Opacities Classification System III (LOCS III) cataract grading between observers at different levels of ophthalmology experience. SETTING: Ophthalmology Department, National University Hospital, Singapore, Singapore. METHODS: In this comparative study, a non-ophthalmology trainee, a basic ophthalmology trainee, and an ophthalmology consultant graded cataracts in 28 patients preoperatively. The observers had a meeting to discuss their interpretations of the LOCS III manual to standardize the grading system and then graded 37 additional patients. RESULTS: There was a statistically significant increase in inter-observer agreement in all 3 LOCS III categories after standardization of the LOCS III system. The kappa values after standardization fell in the moderate (0.41 to 0.60) to substantial (0.61 to 0.80) range. There was no statistically significant relationship between the observer's experience and the kappa values. CONCLUSIONS: There was an increase in inter-observer agreement in all categories after standardization between operators.

Nonseasonal allergic conjunctivitis in the tropics: experience in a tertiary care institution.

PURPOSE: To understand the epidemiology, severity, types of pathology, clinical features, precipitating factors, and treatment outcomes of patients with allergic conjunctivitis in a tropical climate receiving corneal subspecialist intervention. A total of 33 patients with severe allergic conjunctivitis under corneal subspecialist care in National University Hospital, Singapore were studied. DESIGN: A retrospective, noncomparative case series. MAIN OUTCOME MEASURES: epidemiological data, clinical features, complete ophthalmological examination, and treatment types. METHODS: Both eyes of 33 patients seen at the cornea subspecialist clinic between May 2005 and July 2006 were examined at baseline, and followed up. Clinical features, treatment given, and outcome variables through case sheet review were analyzed. RESULTS: Twenty-five patients (75.8%) were male, and 8 (24.2%) were female. Seventeen patients (51.5%) had concomitant allergic rhinitis, 16 patients (48.5%) had asthma, and 17 (51.5%) had associated dermatitis. Only 9 patients (27.3%) had documented precipitating factors. None of the 33 patients said that their symptoms were seasonal; 22 (66.7%) said their symptoms were perennial. Twenty-nine patients (87.9%) had punctate epithelial erosions, and 12 patients eventually progressed to have a corneal epithelial defect or shield ulcer (36.4%). Eleven out of the 33 patients (33.3%) received topical cyclosporine 0.5%. Of these, only 1 (9.1%) had documented complaints of intolerable side effects. CONCLUSION: Allergic conjunctivitis in a non-temperate, non-seasonal climate has different clinical presentations, and varied precipitating factors. The disease in such conditions may respond differently to the usual anti-allergy drug options used in temperate countries.