Dolosigranulum pigrum keratitis: a three-case series.

BACKGROUND: Dolosigranulum pigrum is a commensal inhabitant of the upper respiratory tract suspected to be responsible for ocular infections but no well-described case of D. pigrum corneal infection has been reported. Herein culture and PCR-sequencing-based investigations of corneal scraping specimens confirmed D. pigrum keratitis in three patients. CASE PRESENTATION: Three elderly patients presented with unilateral keratitis. None was a corneal-contact lens wearer, one had previous cataract surgery and another suffered rheumatoid arthritis sicca syndrome. Culturing the corneal scraping specimen was positive for two cases and PCR-sequencing of bacterial 16S rDNA in the presence of negative controls identified D. pigrum in three cases. The two D. pigrum isolates were in-vitro susceptible to penicillin G, amoxicillin, doxycycline, rifampicin and gentamicin. In all cases, surgical treatment of corneal thinning was necessary, but corneal perforation occurred in two cases despite intensive antimicrobial treatment with ticarcillin, gentamicin and vancomycin or levofloxacin eye drops leading to enucleation in one case. CONCLUSIONS: D. pigrum is the likely cause of corneal infection in three patients, with effective antibiotic treatment in two patients.

Comparison of front-surface corneal topography and Bowman membrane specular topography in keratoconus.

PURPOSE: To define the contribution of the corneal epithelium in corneal topography in keratoconus and discuss the implications regarding combined topography-guided photorefractive keratectomy and corneal collagen crosslinking (CXL). SETTING: French National Reference Center for Keratoconus, Bordeaux, France. DESIGN: Case series. METHODS: Specular topographies were performed before and immediately after epithelial removal during conventional CXL surgery in patients with keratoconus. RESULTS: The study included 1 eye with forme fruste keratoconus, 4 eyes in Krumeich stage I, and 3 eyes in stage II. The mean simulated maximum keratometry (K) increased by 2.87 diopters (D) after epithelial removal. The mean effective refractive power increased by a mean of 4.01 D and the astigmatic refractive power, by a mean of 2.17 D. The difference in mean axis deviation was not significant. The mean inferior-superior ratio irregularity index increased 1.51 units. All K and refractive readings except astigmatic refractive axis were significantly increased after epithelial removal. All regularity indices increased significantly without the epithelium. The amplitude of variations in K readings made it difficult to predict the refractive changes after custom laser photoablation based on epithelial-based topography. CONCLUSIONS: The astigmatism refractive axis did not change significantly; therefore, this axis could be useful for astigmatic corrections, whereas the spherical component would not be useful. Topographic changes after epithelial removal can be important but not intuitive in keratoconus eyes. This should be considered in custom topography-guided photoablation strategies when attempting to correct refractive errors at the time of CXL.

Dynamic gonioscopy using optical coherence tomography.

BACKGROUND AND OBJECTIVE: To describe the use of anterior segment optical coherence tomography (AS-OCT) in studying the dynamic changes of the anterior chamber angle by corneal indentation. PATIENTS AND METHODS: In a prospective observational study, the anterior segments of 21 eyes were imaged using AS-OCT. After the initial scan, a second scan was executed on the same areas with a central corneal indentation. An evaluation of the reopening of the angle and its measurement were performed. RESULTS: With AS-OCT, the indirect signs were accurate enough to guide the diagnosis in all plateau iris confirmed by ultrabiomicroscopy. The angle widths were significantly increased after indentation. CONCLUSION: This method would appear to offer a convenient and rapid method of assessing the configuration of the anterior chamber; it may help during the routine clinical assessment and treatment of patients with narrow or closed angles, particularly when gonioscopy is difficult to interpret.

Nocardia transvalensis keratitis: an emerging pathology among travelers returning from Asia.

BACKGROUND: The incidence rate of Nocardia keratitis is increasing, with new species identified thanks to molecular methods. We herein report a case of Nocardia transvalensis keratitis, illustrating this emerging pathology among travellers returning from Asia. CASE PRESENTATION: A 23-year-old man presented with a 10-week history of ocular pain, redness, and blurred vision in his right eye following a projectile foreign body impacting the cornea while motor biking in Thaïland. At presentation, a central epithelial defect with a central whitish stromal infiltrate associated with pinhead satellite infiltrates was observed. Identification with 16S rRNA PCR sequencing and microbiological culture of corneal scraping and revealed N. transvalensis as the causative organism. Treatment was initiated with intensive topical amikacin, oral ketoconazole and oral doxycycline. After a four-week treatment period, the corneal infiltrate decreased so that only a faint subepithelial opacity remained. CONCLUSION: Nocardia organisms should be suspected as the causative agent of any case of keratitis in travelers returning from Asia. With appropriate therapy, Nocardia keratitis resolves, resulting in good visual outcome.