Microbial keratitis and its management at a rural centre: achieving success with limited resources.

PURPOSE: Microbial keratitis is a sight-threatening condition with a higher incidence in agrarian populations. In countries with a high indigent population, due to financial and other constraints, patients prefer to seek therapy locally rather than travel to advanced centres. The aim of this study is to describe the epidemiology, clinical characteristics, and outcomes of 60 consecutive patients with microbial keratitis managed at a rural centre. METHODS: Descriptive case series. All patients clinically diagnosed with infectious keratitis were included. Corneal scrapings were obtained and microbiological identification was done by Gram stain. Anti-microbial therapy was commenced based on smear findings and the patients were followed up till disease resolution. RESULTS: Sixty eyes of 60 patients were diagnosed with microbial keratitis in the study period. The mean age was 47.43 ± 18.69 years. Male:female ratio was 47:53. Risk factors included ocular trauma in the majority of patients (46/60; 76.7%). Microorganisms were identified on 75.6% of smears, with fungal filaments (65.4%) being the most common. Ulcers were central in over half (32/60; 53.3%), and > 3 mm in diameter in over three-fourths (81.6%) of patients. Forty-four patients (73.3%) achieved treatment success whereas 16/60 (26.6%) required referral to our tertiary-eye care facility for management. The median time to resolution was 14 days (IQR 10-26 days). CONCLUSION: Our series demonstrates the feasibility of microbiology-guided therapy in microbial keratitis by ophthalmologists at the secondary rural eye-care level. Two-thirds of the patients could be successfully managed at the rural centre and only severe cases needed a referral to tertiary centres.

Peters Anomaly: Novel Non-Invasive Alternatives to Penetrating Keratoplasty.

BACKGROUND: Peters' anomaly (PA) is the most commonly encountered congenital corneal opacity (CCO) and displays a wide phenotypical range. The relatively recent adoption of high-quality anterior segment imaging in the form of high-frequency ultrasound biomicroscopy and anterior segment optical coherence tomography has aided in the accurate diagnosis of CCOs, facilitated distinction of PA from "pseudo-Peters' anomaly," and aided in prognostication and surgical risk stratification in PA. While the definitive management of PA, especially the more severe forms, is penetrating keratoplasty (PK), long-term success rates have overall been disappointing. This spurred the development of more non-invasive procedures, such as optical iridectomy and the more recently described selective endothelial removal, which represent viable alternatives to PK, at least in the less severe phenotypes of PA. METHODS: Literature searches for the components of this review were performed using PubMed, in September 2021. The following keywords and their iterations were employed for the searches: "Peters' anomaly," "anterior segment dysgenesis," "kerato-irido-lenticular dysgenesis," "congenital corneal opacities." These were entered into the PubMed search engine, revealing 2852 related articles. The inclusion criteria included publications in the English language, specific to Peters' anomaly. Fifty-five studies that were published as systematic reviews or as nonrandomized comparative studies (cohort or case series) on the topic of Peters' anomaly were finally selected for this review. RESULTS: This review provides a summary of Peters' anomaly in the context of advances in diagnosis, classification, and genotype-phenotype correlation of congenital corneal opacities, with a focus on penetrating keratoplasty, its outcomes, and non-invasive surgical options. While conservative therapies such as spontaneous clearing, mydriatic eye drops, and optical iridectomy may have variable success in milder variants of PA, penetrating keratoplasty in these eyes is fraught with several challenges and typically results in poor long-term functional outcomes. The management strategy depends on several variables such as phenotypical severity of PA, laterality, age at presentation, and capacity to adhere to the follow-up schedule. Notwithstanding the choice of treatment, it is essential that early and aggressive amblyopia therapy, a thorough systemic examination, and appropriate referral are undertaken for all patients of PA. CONCLUSION: Peters' anomaly has seen recent advances in diagnosis, but treatment options remain limited. Focus directed towards less-invasive alternatives to keratoplasty may yield better functional outcomes.

Assessment of genotypes, endosymbionts and clinical characteristics of Acanthamoeba recovered from ocular infection.

INTRODUCTION: Acanthamoeba is an emerging pathogen, infamous for its resilience against antiprotozoal compounds, disinfectants and harsh environments. It is known to cause keratitis, a sight-threatening, painful and difficult to treat corneal infection which is often reported among contact lens wearers and patients with ocular trauma. Acanthamoeba comprises over 24 species and currently 23 genotypes (T1-T23) have been identified. AIMS: This retrospective study was designed to examine the Acanthamoeba species and genotypes recovered from patients with Acanthamoeba keratitis (AK), determine the presence of endosymbionts in ocular isolates of Acanthamoeba and review the clinical presentations. METHODOLOGY: Thirteen culture-confirmed AK patients treated in a tertiary eye care facility in Hyderabad, India from February to October 2020 were included in this study. The clinical manifestations, medications and visual outcomes of all patients were obtained from medical records. The Acanthamoeba isolates were identified by sequencing the ribosomal nuclear subunit (rns) gene. Acanthamoeba isolates were assessed for the presence of bacterial or fungal endosymbionts using molecular assays, PCR and fluorescence in situ hybridization (FISH). RESULTS: The mean age of the patients was 33 years (SD ± 17.4; 95% CI 22.5 to 43.5 years). Six (46.2%) cases had AK associated risk factors; four patients had ocular trauma and two were contact lens wearers. A. culbertsoni (6/13, 46.2%) was the most common species, followed by A. polyphaga and A. triangularis. Most of the isolates (12/13) belonged to genotype T4 and one was a T12; three sub-clusters T4A, T4B, and T4F were identified within the T4 genotype. There was no significant association between Acanthamoeba types and clinical outcomes. Eight (61.5%) isolates harboured intracellular bacteria and one contained Malassezia restricta. The presence of intracellular microbes was associated with a higher proportion of stromal infiltrates (88.9%, 8/9), epithelial defect (55.6%, 5/9) and hypopyon (55.6%, 5/9) compared to 50% (2/4), 25% (1/4) and 25% (1/4) AK cases without intracellular microbes, respectively. CONCLUSIONS: Genotype T4 was the predominant isolate in southern India. This is the second report of T12 genotype identified from AK patient in India, which is rarely reported worldwide. The majority of the Acanthamoeba clinical isolates in this study harboured intracellular microbes, which may impact clinical characteristics of AK.