Ophthalmic viscoelastics commonly used in cataract surgery: A microbiota investigation.

PURPOSE: To survey commonly used, sterile ophthalmic viscoelastic materials used during routine cataract surgery for the presence of bacterial DNA and/or viable bacteria and endotoxin quantification. METHODS: Samples from three different ophthalmic viscoelastic manufacturers and three different production lots per manufacturer were collected for 16 S ribosomal ribonucleic acid (rRNA) sequencing and conventional aerobic and capnophilic bacterial culture. Other samples of viscoelastic material from the same three manufacturers were collected for endotoxin quantification using a commercially available Limulus amebocyte lysate (LAL) assay. Statistical analysis was performed using Sigma Plot 14.0, and R v4.0.2.0. Differences (p ≤ .05) between sample collection sites in total DNA concentration, microbial richness, mean intra-group distances, and endotoxin quantification alongside reagent controls were evaluated. RESULTS: Culture yielded two isolates, identified as Staphylococcus epidermidis and Bacillus megaterium. 16 S rRNA sequencing revealed no differences between brands in richness or overall composition. The most common bacterial DNA detected across all brands was Staphylococcus sp., Cutibacterium sp., Flavobacterium sp., and Lactobacillus sp. A significant difference was found between the median endotoxin concentration between Anvision and Hyvisc® viscoelastic (Anvision: 0.171 EU/mL, Hyvisc®: 0.03 EU/mL; p < .001). CONCLUSIONS: No brand-specific differences in bacterial DNA were detected in the viscoelastic materials. Staphylococcus, Cutibacterium, Flavobacterium, and Lactobacillus were the dominant contributors to the bacterial DNA detected. Although Anvision viscoelastic samples contained significantly more endotoxin than Hyvisc® viscoelastic samples, endotoxin concentrations were below the FDA limit of 0.2 EU/mL for both manufacturers. These data further the understanding of inflammatory outcomes following cataract surgery.

Characterization of postoperative "fibrin web" formation after canine cataract surgery.

PURPOSE: To describe the occurrence and associated factors for "fibrin web" (FW) formation following phacoemulsification in dogs. METHODS: A retrospective review of medical records of all dogs undergoing phacoemulsification (MU-Veterinary Health Center, 2014-2018) was conducted to associate FW formation with signalment, systemic co-morbidities, cataract stage, surgeon (resident vs faculty), phacoemulsification time, IOL, and intracameral injections including viscoelastic type. Both univariate and multivariate statistical analyses were performed to evaluate associations among variables with FW formation. RESULTS: Data from 398 eyes on 201 dogs were included; 4 left eyes (4 dogs) developed presumptive endophthalmitis and were excluded from further analysis. Forty-eight eyes did not have cataract surgery. Hence, 350 eyes on 201 dogs were included in the analyses. Among these, 84 eyes (59 dogs) developed a FW. Univariate analyses showed that the odds of FW increased with age and phacoemulsification time. Additionally, FW web was associated lens type, lens brand, and viscoelastic type. Multivariate analyses showed that when comparing lens types in combination with a particular viscoelastic, viscoelastic impacted the estimated prevalence of FW formation the most. In contrast, when the data were analyzed by lens brand, lens brand impacted prevalence more than viscoelastic type. Diabetes mellitus was not associated with FW formation. CONCLUSIONS: Based on the available data, intraocular lens implantation, viscoelastic type, dog age, and phacoemulsification time were associated with FW formation. Diabetes mellitus, gender, cataract stage, surgeon, intracameral injections other than viscoeleastic, and intra- and postoperative complications were not associated with FW formation.

Cactus-induced keratoconjunctivitis in Texas: A case series of three dogs and one cat.

OBJECTIVE: To describe the historical, clinical, and diagnostic features of small animal patients affected by cactus-induced keratoconjunctivitis and their response to therapy. ANIMALS STUDIED: Three dogs and one cat. PROCEDURES: Ophthalmic examination directed subsequent selected diagnostic tests in each case including light microscopy of extracted foreign bodies, in vivo confocal microscopy (IVCM), corneal histopathology, and corneal bacterial culture. Treatments consisted of foreign body surgical extraction with concurrent medical therapy (three cases), or medical therapy alone (one case). RESULTS: Clinical histories obtained supported acute cactus injury in all cases. Ophthalmic abnormalities were unilateral in each case and included ulcerative keratoconjunctivitis associated with linear, microscopic conjunctival and/or corneal penetrating cactus spines, known as glochids. Light microscopy and IVCM showed glochids to be heavily barbed, consistent with the spine morphology Prickly Pear (Opuntia) cactus species. Bacterial culture yielded Proprionicimonas sp. in one case with keratomalacia. Surgical extraction of spines was challenging, and residual conjunctival and/or corneal glochids were present in all cases. Patient discomfort resolved at a median of 21 days (range 10-51 days). Vision-threatening complications were not observed in any case at the time of last follow-up examination. Epithelial downgrowth, demonstrated by IVCM and histopathology, was present in one case at 108-day follow-up. CONCLUSIONS: Cactus-induced keratoconjunctivitis should be considered as a differential in regions in which Opuntia cacti are prevalent, and microscopic ocular foreign bodies are observed. Although glochids are difficult to extract, positive clinical outcomes can occur in small animal patients despite the presence of residual organic corneal foreign material.

Molecular and microbiological evidence of bacterial contamination of intraocular lenses commonly used in canine cataract surgery.

Inflammatory outcomes, including toxic anterior segment syndrome (TASS) and infectious endophthalmitis, are potentially painful, blinding complications following cataract surgery. In an in vitro pilot study, commercially available, sterile foldable intraocular lenses (IOLs) used during routine canine cataract surgery, and their packaging fluid were surveyed for the presence of bacterial DNA and/or viable (cultivable) bacteria. Swabs from IOLs and packaging fluid from three different veterinary manufacturers and three different production lots/manufacturer were collected for 16S ribosomal ribonucleic acid (rRNA) sequencing. Packaging fluid samples were collected for aerobic/capnophilic bacterial culture. Culture yielded one isolate, identified as Staphylococcus epidermidis. 16S rRNA sequencing revealed distinct brand-specific bacterial DNA profiles, conserved between IOLs and packaging fluid of all production lots within each manufacturer. The dominant taxonomy differentiating each manufacturer was annotated as Staphylococcus sp, and was a 100% match to S. epidermidis. Distinct mixtures of bacterial DNA are present and consistent in IOLs and packaging fluid depending on the manufacturer, and Staphylococcus is the dominant contributor to the bacterial DNA detected. Caralens products had a significantly lower amount of Staphylococcus spp. compared to Anvision and Dioptrix products.