Matthew C. Caldwell

Air bubble-associated endothelial trauma in descemet stripping automated endothelial keratoplasty.

PURPOSE To evaluate endothelial cell trauma by anterior chamber (AC) air bubbles in Descemet stripping automated endothelial keratoplasty (DSAEK). DESIGN Laboratory investigation. METHODS Twelve human donor corneas (6 pairs) were sectioned using an automated microkeratome system (Moria ALTK System, Antony, France). One cornea of each pair was mounted on a Moria artificial AC, and an air bubble was injected to fill 40% of the AC. The apparatus was rotated 180 degrees for a total of 50 times to simulate air bubble trauma. The fellow corneas were used as controls. Each endothelial graft was stained with 0.25% Trypan blue for 90 seconds followed by 0.2% alizarin red for 2 minutes, and digital photomicrographs were obtained. Abnormally staining areas indicative of graft injury were removed digitally from the total graft area. The proportion of uninjured corneal endothelium was calculated, and differences were analyzed. RESULTS In this ex vivo model of air bubble trauma, the proportion of viable graft endothelium after air bubble injury was 79.8 +/- 0.04% (n = 6). The proportion of viable endothelium in the control group was 89.9 +/- 0.02% (n = 6). The statistically significant mean difference of 10.1% (P = .03) is indicative of greater endothelial injury after air bubble trauma. CONCLUSIONS Using this model, a moderate but significant amount of endothelial cell damage was associated with air bubble trauma compared with the control group. Air bubble trauma may account partially for the loss of endothelial cell density after DSAEK surgery and may impact graft survival.

The Histology of Graft Adhesion in Descemet Stripping with Endothelial Keratoplasty

PURPOSE To describe the histologic findings of full-thickness corneas from penetrating keratoplasty (PK) in 10 patients with a prior history of Descemet stripping with endothelial keratoplasty. DESIGN Retrospective review of the histopathology of 10 PK specimens. METHODS We reviewed histologic sections stained with hematoxylin and eosin, periodic acid-Schiff, and colloidal iron stains from 10 PK specimens, which had been trisected and submitted in their entirety. Clinical data were abstracted from the medical record. RESULTS The interface between host and graft in most cases was barely perceptible with minimal changes in the degree of tissue eosinophilia, a subtle increase in keratocyte cellularity focally, or the presence of melanin granules within keratocytes. Residual host Descemet membrane (DM) was found in 8 of the 10 cases, most often at the edges of the graft. In no case did the presence of DM appear to hinder graft adhesion. CONCLUSION The adhesion of Descemet stripping with endothelial keratoplasty grafts is not associated with significant scarring or keratocyte proliferation. Contrary to previous assumptions, retained DM did not appear to hinder graft adhesion, raising the possibility that removal of DM may be unnecessary for endothelial transplantation.

Candida glabrata endophthalmitis following penetrating keratoplasty

We report a case of Candida glabrata endophthalmitis following penetrating keratoplasty in a 57-year-old man. The infection was thought to be treated successfully with intravitreal amphotericin B but flared 7 months later following cataract extraction and eventually required explantation of the intraocular lens and therapeutic keratoplasty. The literature regarding this rare infection is reviewed. Candida glabrata, an uncommon ocular pathogen, is being reported with increasing frequency and with a notable predilection for post-keratoplasty eyes. In the 10 reported cases, there is 100% concordance between host and donor tissue cultures. In half the cases, there was a latent period of several months. These infections can be difficult to treat because C glabrata is often resistant to the antifungal agents commonly used to treat Candida albicans.

Corneal wound integrity and architecture after phacoemulsification: Comparative analysis of corneal wounds created by silicon and steel blades

Little is known about the effect of keratome type on postoperative wound integrity and architecture. Studies comparing metallic blades and diamond blades show conflicting results in terms of which type creates a less traumatized wound. Recently, a new line of surgical blades composed of siliconmaterial was introduced. Studies of the quality of corneal wounds created by silicon blades are needed but difficult to find in the peer-reviewed literature. We compared the postoperative architecture and integrity of corneal wounds created by metallic and silicon keratomes by observation of wound leakage, scanning electron microscopy (SEM) of the wounds and blades, and histopathologic analysis of the wounds in an ex vivo setting. Each of 10 human cadaver eyes (2 groups of 5 eyes) had a 2.8 mm clear corneal incision by a silicon blade (BD Atomic Edge safety slit knife [BDMedical]) or ametallic blade (Sharpoint slit knife [Surgical Specialties Corp.]). Care was taken to ensure that all eyes were of similar firmness before wound creation. A small amount of balanced salt solution was injected into the anterior chamber of softer eyes to prevent bias in wound construction. All incisions were created in a standard biplanar fashionwith a length approximately equal to the initial width of 2.8 mm. A new blade was used for each eye.

Visual outcomes after femtosecond laser in situ keratomileusis flap complications.

Purpose To compare visual outcomes in normal and complicated laser in situ keratomileusis (LASIK) flaps constructed with a femtosecond laser. Setting Wilford Hall Ambulatory Surgical Center, San Antonio, Texas. Design Retrospective chart review. Methods The main outcome measures were uncorrected distance visual acuity (UDVA) and best‐corrected distance visual acuity (CDVA) at 1 month post‐surgery, which were compared in patients with and without complications during flap creation. Results This retrospective chart review identified 586 eyes of 293 consecutive patients who had bilateral simultaneous femtosecond LASIK for myopia. A normal flap was attained in 539 (91.8%) of patients. At 1 month postoperatively, the mean UDVA was 20/19.1, and the CDVA was 20/16.8. 3 (0.51%) of patients experienced an incomplete side cut or intraoperative flap tear (the mean 1‐month uncorrected distance visual acuity [UDVA] was 20/17.5 and the corrected distance visual acuity [CDVA] was 20/16.9 in both groups). Microstriae were seen in 28 (4.8%) of patients (mean 1‐month UDVA, 20/21.7; CDVA, 20/17.4). Diffuse lamellar keratitis appeared in 4 (0.68%) of patients (mean 1‐month UDVA, 20/21.7; CDVA, 20/15.6). Epithelial ingrowth developed in 9 (1.5%) of patients (mean 1‐month UDVA, 20/18.7; CDVA, 20/16.9). There was no statistically significant difference in UDVA or CDVA at 1 month postoperatively between complicated and uncomplicated flaps (P > .05), and complicated flaps did not lose a statistically significant amount of CDVA or low‐contrast acuity (CDVA 5%) compared to preoperative values. Conclusions Intraoperative and postoperative complications of LASIK flaps created with the femtosecond laser were rare, and their visual outcomes were equivalent to those of normal flaps. Financial Disclosure Charles D. Reilly is a consultant to Alcon Labs and Abbott Medical Optics at present, but was not at the time of the study. For the remaining authors none are declared.

Retrospective Analysis Comparing the Preoperative and Postoperative "Q" Values for 2 Different Lasers in Refractive Surgery.

Purpose: To compare the presurgical and postsurgical corneal asphericity, or “Q value,” between VISX Wavefront-guided treatment and Allegretto Wave Wavefront-optimized treatment in photorefractive keratectomy for the correction of myopia. Methods: This is a retrospective database analysis performed at the Joint Warfighter Refractive Surgery Center, Lackland Air Force Base, TX. All data were accessed through the Institutional Review Board-approved Joint Warfighter Refractive Surgery Center database. Fifty-one patient records (102 eyes) were reviewed to determine the change in the Q value after photorefractive keratectomy for the correction of myopia. Results: The average change in the Q value per diopter of treatment sphere over the entire study population was 0.12 (±0.04) for Allegretto and 0.14 (±0.04) for VISX (P = 0.004). There was no statistical difference among the preoperative and postoperative best-corrected visual acuities (BCVAs), low-contrast BCVA (BCVA 5%), or quality of vision complaints between both platforms. Conclusions: Low to moderate myopic correction with the Allegretto laser was associated with a smaller change in the Q value per diopter of treatment and therefore more closely maintained the original prolate shape of the cornea when compared with VISX. No difference in the postoperative visual outcome between both groups was detected.

Optical Spectral Imaging For Breast Margin Assessment: A Comprehensive Assessment of Sources of Contrast

Achieving tumor-free margins is desired to avoid recurrence. Diffuse reflectance imaging can assess margin status; however, understanding kinetics, cautery, and patient variability is needed to exploit optical contrast to detect positive margins.