Corneal confocal microscopy: Neurologic disease biomarker in Friedreich ataxia.

OBJECTIVE: Friedreich ataxia (FRDA), an autosomal recessive neurodegenerative disease caused by mutations in the gene encoding for the mitochondrial protein frataxin, is characterized by ataxia and gait instability, immobility, and eventual death. We evaluated corneal confocal microscopy (CCM) quantification of corneal nerve morphology as a novel, noninvasive, in vivo quantitative imaging biomarker for the severity of neurological manifestations in FRDA. METHODS: Corneal nerve fiber density, branch density, and fiber length were quantified in individuals with FRDA (n = 23) and healthy age-matched controls (n = 14). All individuals underwent genetic testing and a detailed neurological assessment with the Scale for the Assessment and Rating of Ataxia (SARA) and Friedreich's Ataxia Rating Scale (FARS). A subset of individuals with FRDA who were ambulatory underwent quantitative gait assessment. RESULTS: CCM demonstrated a significant reduction in nerve fiber density and length in FRDA compared to healthy controls. Importantly, CCM parameters correlated with genotype, SARA and FARS neurological scales, and linear regression modeling of CCM nerve parameter-generated equations that predict the neurologic severity of FRDA. INTERPRETATION: Together, the data suggest that CCM quantification of corneal nerve morphology is a rapid, sensitive imaging biomarker for quantifying the severity of neurologic disease in individuals with FRDA. Ann Neurol 2018;84:893-904.

Accuracy of Holladay 2 formula using IOLMaster parameters in the absence of lens thickness value.

BACKGROUND: The accuracy of the Holladay 2 (H2) formula is well-documented. This formula requires seven variables to estimate effective lens position (ELP) for the IOL power calculation. The lens thickness (LT) value is one of the required variables. Interestingly, the IOLMaster, which is one of the most commonly used optical biometers, can provide all the required ocular variables except LT value. It has become a pertinent issue to evaluate the accuracy of theH2 formula when it is used without the LT value. The purpose of this study was to evaluate the results when using the H2 formula, without the LT value, and compare such results to those obtained using the Haigis formula and the Hoffer Q formula. METHODS: The Institutional review board (IRB) gave their approval for the conduct of this prospective comparative study. One hundred and sixty-three eyes of 143 cataract patients from the Ophthalmology Department, Siriraj Hospital, Thailand were recruited. All eyes were measured using the IOLMaster (Carl Zeiss Meditec, Jena, Germany) for keratometry (K), axial length (AL), anterior chamber depth (ACD), and horizontal white-to-white (WTW) corneal diameter. Then, the LT measurement was obtained by A-scan ultrasonography (Quantel Axis-II, Quantel Medical, USA). Every patient underwent uncomplicated phacoemulsification by a single surgeon (NC) with a single technique using a single IOL model. Post-operative refraction was obtained at 3 months. The mean absolute errors (MAEs), median absolute errors (MedAEs) and percentage of the eyes within ±0.25, ±0.50, and ±1.00 D of predicted refraction was calculated for H2 formula both with and without LT input, Haigis, and Hoffer Q formula. The results were also classified into a group of short AL (<22.0 mm), average AL (22.0 to 24.5 mm) and long AL (>24.5 mm). RESULTS: There was no statistically significant difference in either MAEs or MedAEs of all formulas in all AL groups including the H2 with and without LT. There was a trend toward lower MAEs and MedAEs for H2 in the long AL group. Percentage of the eyes within ±0.25, ±0.50, and ±1.00 D of predicted refraction were similar in all AL groups. CONCLUSION: The preliminary results of this study showed that the H2 formula performed well even without the LT value. It was comparable to the Haigis and Hoffer Q formulas.

Microbiology of primary acquired nasolacrimal duct obstruction: simple epiphora, acute dacryocystitis, and chronic dacryocystitis.

PURPOSE: The aim of this study was to determine the microbiology of primary acquired nasolacrimal duct obstruction (PANDO) and its antimicrobial susceptibilities. METHODS: Ninety-three patients (100 eyes) diagnosed with PANDO, categorized as acute, chronic dacryocystitis, or simple epiphora, were prospectively enrolled. Lacrimal sac contents were cultured for aerobic and anaerobic bacteria and fungi. Cultured organisms were identified, and antimicrobial susceptibility testing was performed for aerobic bacteria. RESULTS: Seventy-nine of the 100 samples were culture positive. One hundred twenty-seven organisms were isolated, and 29 different species were identified. Most microorganisms were Gram-positive bacteria (45 samples or 57.0% of all positive culture samples), whereas Gram-negative bacteria, anaerobic bacteria, and fungi were found in 39 (49.4%), 24 (30.4%), and four samples (5.1%), respectively. The most frequently isolated group was coagulase-negative staphylococci (27.8%), followed by nonspore-forming Gram-positive rods (anaerobe) (17.7%) and Pseudomonas aeruginosa (15.2%). Of the 100 samples, five, 45, and 50 samples were obtained from patients with acute dacryocystitis, chronic dacryocystitis, and simple epiphora, respectively. Subgroup analysis showed that Gram-negative organisms were isolated more frequently from the chronic dacryocystitis subgroup than from the simple epiphora subgroup (P=0.012). Antimicrobial susceptibility testing demonstrated that ciprofloxacin was the most effective drug against all Gram-positive and Gram-negative organisms. CONCLUSION: Patients with PANDO, with or without clinical signs of lacrimal infection, were culture positive. Gram-negative organisms were frequently isolated, which were different from previous studies. Ciprofloxacin was the most effective agent against all Gram-positive and Gram-negative organisms.