Jennifer Y. Li

High-resolution spectral domain anterior segment optical coherence tomography in type 1 boston keratoprosthesis

Purpose: To report the results of imaging using high-resolution, Fourier domain anterior segment optical coherence tomography (AS-OCT) to evaluate patients with a type 1 Boston Keratoprosthesis (KPro). Methods: We performed a retrospective comparative study of patients in whom we implanted the Boston KPro. A total of 26 eyes of 23 patients from the Cornea Service at the University of California Davis Eye Center were included. Subjects were evaluated with the Spectralis AS-OCT (Heidelberg Engineering GmbH). Results: Preoperative diagnoses for KPro surgery included failed corneal transplant (69%), chemical burn (23%), and aniridia (8%). The average age of patients was 63.2 years (range, 17–88 years). Fifty-four percent of the patients were female. The mean duration between the KPro surgery and the acquisition of high-resolution AS-OCT imaging was 35.8 months (range, 2–90 months). The most commonly observed finding was retroprosthetic membrane formation, which we found in 77% of KPro eyes. In 65% of KPro eyes, we identified epithelium behind the front plate, and in 54%, we identified an epithelial lip over the anterior surface of the KPro front plate. In 31% of KPro eyes, we identified periprosthetic cysts, gaps or spaces, and thinning in the corneal carrier graft. Conclusions: Fourier domain AS-OCT is a useful noninvasive imaging technique in patients with a KPro and provides the ability to identify changes that are sometimes difficult to appreciate by clinical evaluation. The higher resolution Fourier domain systems may aid in the clinical diagnosis and management of pathology that might not be imaged with instruments of lower resolution. AS-OCT has the potential for monitoring the anatomic stability of an implanted KPro and may also help to monitor for complications. Moreover, high-resolution imaging may enhance our understanding of periprosthetic anatomy.

Use of Scleral Lenses and Miniscleral Lenses After Penetrating Keratoplasty.

Purpose: To examine the clinical outcomes of scleral lenses for visual rehabilitation after penetrating keratoplasty (PK). Methods: A retrospective review was conducted for 34 patients (48 eyes) who had a history of prior PK and were fit with scleral lenses between October 2009 and December 2013 at the UC Davis Eye Center. Results: The most common initial indication for PK was keratoconus in 27 eyes (56%). Thirty-three eyes (69%) had previously been fit with other types of contact lenses, with small-diameter rigid gas-permeable lenses being the most common. The improvement in best-corrected visual acuity with a scleral lens compared with prior spectacle refraction or other contact lens was a mean of two best-corrected visual acuity lines. Forty-four eyes (91.7%) achieved functional vision with best scleral lens-corrected visual acuities of 20/40 or better. Patients who continued wearing scleral lenses were significantly more likely to report “good” subjective vision compared with patients who abandoned scleral lens wear (P=0.009), although change in objective best-corrected visual acuity did not differ significantly. There were no cases of infectious keratitis. Six eyes (12.5%) developed graft rejection; 3 were able to resume scleral lens wear. Nineteen eyes (39.5%) discontinued scleral lens wear for various reasons, the most common reason for discontinuation of lens wear was difficulty with scleral lens insertion or removal (8 eyes, 42.1%). Conclusion: Scleral lenses are effective and safe in patients who have had PK. There was a mean gain in visual acuity, with the majority of patients achieving 20/40 vision or better. The patients subjective perception of vision was a significant factor in determining whether scleral lens wear was continued or abandoned.

In Vitro Evaluation of Endothelial Cell Loss Using the Neusidl Corneal Inserter.

Purpose: To determine the immediate endothelial cell loss (ECL) resulting from insertion of a precut donor button using the Neusidl Corneal Inserter (NCI) and compare it with the previously published ECL resulting from insertion of a folded donor button using non-coapting forceps. Methods: Ten corneas were precut for Descemet stripping automated endothelial keratoplasty and trephinated to a diameter of 8.0 mm (n = 5) or 8.5 mm (n = 5). Each tissue was placed onto the platform of a new NCI spatula and inserted into a cadaveric whole globe through a 5.2 mm incision. The tissue was carefully removed and stained with trypan blue and alizarin red to detect damaged endothelium. ECL was estimated using Adobe Photoshop planimetry. Mean ECL was compared with previously reported studies of forceps insertion with a one-sample t test, using SPSS v. 19. Geographic patterns of ECL were also documented. Results: Mean ECL was 15.6% (95% confidence interval, 13.8–17.4). We were unable to detect a difference in ECL compared with previous insertion methods studied (P < 0.001). The pattern of damage from the NCI was different than that previously seen with forceps insertion. Conclusion: Immediate endothelial damage resulting from use of the NCI for insertion of Descemet stripping automated endothelial keratoplasty tissue is comparable with that seen with a standard forceps technique, but with a different damage pattern.

Superficial Keratectomy and Conjunctival Advancement Hood Flap (SKCAHF) for the Management of Bullous Keratopathy: Validation in Dogs With Spontaneous Disease.

Purpose: To evaluate the efficacy of superficial keratectomy and conjunctival advancement hood flap (SKCAHF) for the treatment of bullous keratopathy in canine patients. Methods: Nine dogs (12 eyes) diagnosed with progressive corneal edema underwent superficial keratectomy followed by placement of conjunctival advancement hood flaps. The canine patients were examined pre- and postoperatively using in vivo confocal microscopy, ultrasonic pachymetry (USP), and Fourier-domain optical coherence tomography (FD-OCT). All owners responded to a survey regarding treatment outcomes. Results: Mean central corneal thickness (CCT) as measured by FD-OCT was 1163 ± 290 &mgr;m preoperatively and significantly decreased postoperatively to 795 ± 197 &mgr;m (P = 0.001), 869 ± 190 &mgr;m (P = 0.005), and 969 ± 162 &mgr;m (P = 0.033) at median postoperative evaluations occurring at 2.2, 6.8, and 12.3 months, respectively. Owners reported significant improvement (P < 0.05) in vision and corneal cloudiness at 6.8 and 12.3 months postoperatively. The percentage of cornea covered by the conjunctival flap was correlated (P = 0.0159) with a reduction in CCT by USP at 12.3 months postoperatively. All canine patients were comfortable pre- and postoperatively. Conclusions: SKCAHF results in a reduction of corneal thickness in canine patients with bullous keratopathy. The increase in corneal thickness over time, after performing SKCAHF, is likely because of progressive endothelial decompensation. This surgery is a potentially effective intervention for progressive corneal edema in dogs that may have value in treatment of human patients with bullous keratopathy.

Evaluation of microbial flora in eyes with a Boston type 1 Keratoprosthesis.

Purpose: To evaluate the microbial flora of eyes with a Boston Keratoprosthesis (K-Pro). Methods: A prospective study was performed for 17 eyes of 15 patients who underwent a K-Pro implantation between September 2005 and June 2011. Preoperative diagnoses included failed corneal grafts, limbal stem cell deficiency, chemical burns, and Stevens–Johnson Syndrome. The patients used topical antibiotics after their surgery including a fluoroquinolone, polymyxin–trimethoprim, vancomycin, or a combination of the 3. The conjunctiva in the study eye was swabbed and cultured. A separate culture was taken of the contralateral eye as well. If available, the bandage contact lens was removed, and half of it was placed in thioglycolate broth, and half in 5 mL of a sterile balanced salt solution. The contact lens in the balanced salt solution was sonicated using a QSonica Q125 sonicator (Newtown, CT) for 1 minute, at an amplitude of 20%. Ten microliters of fluid was subsequently cultured. Results: Of the patients who underwent the K-Pro surgery during that time period, 15 patients with 17 eyes were able to participate in the data collection. Nine of the 17 eyes implanted with the K-Pro (53%) had positive cultures. Two of the 13 (15%) of the control swabs exhibited bacterial growth. Eight percent (1/12) of the sonicated lenses were positive on culture, whereas 4/12 (33%) of the lenses placed in thioglycolate broth were positive for organisms. Conclusions: Despite being on antibiotics, eyes implanted with the K-Pro were more likely to have a positive conjunctival culture in our cohort as compared with that of fellow eyes.

Single-Pass Microkeratome System for Eye Bank DSAEK Tissue Preparation: Is Stromal Bed Thickness Predictable and Reproducible?

Purpose: To evaluate the predictability and reproducibility of stromal bed thickness for single-pass donor Descemet stripping automated endothelial keratoplasty (DSAEK) tissue preparation, using the ML7 Microkeratome Donor Cornea System (Med-logics Inc, Athens, TX). Methods: In this retrospective chart review of 256 consecutive corneal tissue preparations for DSAEK surgery, from June 2013 to August 2014, tissue thicknesses were divided into 3 groups, depending on surgeon preference: <91 &mgr;m (group A), 90 to 120 &mgr;m (group B), and 120 to 160 &mgr;m (group C). Precut and postcut data were recorded. Results: Average postcut donor corneal thickness was 114 ± 30 &mgr;m (range 60–183 &mgr;m), whereas the average in group A was 97 ± 23 &mgr;m (range 60–128), in group B was 113 ± 21 &mgr;m (range 77–179), and in group C was 134 ± 43 (range 89–183). Average postcut endothelial cell density was very adequate at 3013 ± 250 cells per square millimeter. There were a total of 7 failed procedures from 256 attempts, which represents a rate of 2.7%. This rate decreases to 1.5% when analyzing the last 200 cuts. Conclusions: The ML7 Microkeratome Donor Cornea System allows for reliable and reproducible DSAEK tissue preparation. Ultrathin DSAEK tissues can be prepared with a single-pass. Aiming for a graft thickness between 90 and 120 &mgr;m seems to be most reliable.

The safety and efficacy of linezolid and daptomycin as an additive in Optisol-GS against methicillin-resistant Staphylococcus aureus.

Purpose: To evaluate the efficacy of adding either linezolid or daptomycin to Optisol-GS donor storage medium in reducing methicillin-resistant Staphylococcus aureus (MRSA) contamination of donor corneas. Methods: Optisol-GS was supplemented with either linezolid at 2×, 4×, or 10× minimum inhibitory concentration (MIC) or daptomycin and calcium at 5× or 50× MIC. Unsupplemented control groups were also used. Gentamicin-sensitive and gentamicin-resistant isolates of MRSA were added, and vials were refrigerated for 48 hours followed by sampling for viable colony counts immediately upon removal from refrigeration and after warming to room temperature for 3 hours. Safety studies of Optisol-GS supplemented with 50× MIC daptomycin and calcium were performed by evaluating the central corneal thickness and endothelial cell density of the donor cornea. Stability of daptomycin in Optisol-GS at storage was also tested. Results: No added benefit was observed with linezolid supplementation to Optisol-GS against gentamicin-sensitive MRSA, with reduction in viable colony counts by >90% in all groups. No benefit was observed with linezolid supplementation against gentamicin-resistant MRSA, with the majority of inocula remaining viable in all groups. Viable counts of gentamicin-sensitive MRSA and gentamicin-resistant MRSA were effectively reduced with both 5× MIC and 50× MIC daptomycin supplementation. 50× MIC daptomycin–supplemented Optisol-GS had no appreciable effect on the central corneal thickness or endothelial cell density of the donor cornea and was stable at storage for 14 days. Conclusions: The addition of daptomycin to Optisol-GS significantly increases the anti-MRSA activity of the medium without any apparent negative effects on donor corneal tissue.