Majid Moshirfar

Corneal profile analysis after Descemet stripping endothelial keratoplasty and its relationship to postoperative hyperopic shift

PURPOSE: To evaluate changes in the corneal profile after Descemet stripping endothelial keratoplasty (DSEK) using anterior segment optical coherence tomography (AS‐OCT) analysis and to describe its relationship to a dynamic postoperative hyperopic shift. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, USA. METHODS: In this retrospective observational study, 9 eyes had DSEK and were followed with manifest refractions and AS‐OCT analysis. To assess changes in the thickness of the cornea, measurements for each AS‐OCT image were taken at the vertex of the cornea, at 1.5 mm on each side of the vertex, and at the distal edges of the graft. RESULTS: Patients were followed for a mean of 134 days (range 46 to 228 days). Monthly Graft thinning rates were 5.2 μm per month at the vertex, 7.9 μm per month 1.5 mm from the vertex, and 26 μm per month at the edges, with the edges thinning significantly faster than the cornea vertex (P = .0024) and the points on either side of the 3.0 mm visual axis (P = .0018). The mean spherical equivalent (SE) showed an initial hyperopic shift that decreased over the ensuing 100 to 200 days postoperatively. The mean monthly postoperative SE change was −0.25 diopter (D) with a mean preoperative to postoperative SE change of +1.26 D. CONCLUSIONS: The donor graft underwent changes after DSEK, which may account for the induced hyperopia and its diminishment over time via changes in the posterior corneal curvature. Results suggest that intraocular lenses be targeted to −1.00 to −1.25 D of myopia for combined DSEK and cataract procedures.

Laser in situ keratomileusis flap complications using mechanical microkeratome versus femtosecond laser: Retrospective comparison

PURPOSE: To compare the incidence of flap complications after creation of laser in situ keratomileusis (LASIK) flaps using a zero‐compression microkeratome or a femtosecond laser. SETTING: John A. Moran Eye Center, Department of Ophthalmology, University of Utah, Salt Lake City, Utah, USA. DESIGN: Evidence‐based manuscript. METHODS: The flap complication rate was evaluated during the initial 18 months of experience using a zero‐compression microkeratome (Hansatome) or a femtosecond laser (IntraLase FS60) for flap creation. RESULTS: The flap complication rate was 14.2% in the microkeratome group and 15.2% in the femtosecond laser group (P = .5437). The intraoperative flap complication rate was 5.3% and 2.9%, respectively (P = .0111), and the postoperative flap complication rate, 8.9% and 12.3%, respectively (P = .0201). The most common intraoperative complication in the microkeratome group was major epithelial defect/sloughing; the rate (2.6%) was statistically significantly higher than in the femtosecond laser group (P = .0006). The most common postoperative complication in both groups was diffuse lamellar keratitis (DLK) (6.0%, microkeratome; 10.6%, femtosecond laser) (P = .0002). CONCLUSION: Although the total complication rates between the 2 groups were similar, the microkeratome group had significantly more epithelial defects intraoperatively and the femtosecond laser group had significantly more DLK cases postoperatively. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Third- and fourth-generation fluoroquinolones: Retrospective comparison of endophthalmitis after cataract surgery performed over 10 years

PURPOSE: To determine differences in endophthalmitis rates with prophylactic use of third‐ versus fourth‐generation fluoroquinolones in cataract surgery. SETTING: University hospitals. METHODS: This retrospective cross‐sectional (prevalence) study looked at patients who had phacoemulsification at a university eye center over a 10‐year period. A nosocomial infectious reporting database was used to report endophthalmitis occurrences. The following were performed: a retrospective analysis of prospectively collected data to establish endophthalmitis rates, a prevalence analysis of the postoperative quinolone antibiotic prescribed, and a comparative analysis of endophthalmitis rate versus postoperative quinolone prescribed for all reported endophthalmitis cases. The main outcome measure was occurrence of endophthalmitis after cataract surgery. RESULTS: From January 1997 to December 2007, 29 276 patients had phacoemulsification cataract surgery. Forty cases of postoperative bacterial endophthalmitis were reported. The endophthalmitis rate from January 1997 to August 2003 associated with use of third‐generation fluoroquinolones (ciprofloxacin, ofloxacin) was 0.197% (33/16 710). The rate from September 2003 to December 2007 associated with fourth‐generation fluoroquinolones (gatifloxacin, moxifloxacin) was 0.056% (7/12 566). The difference between third‐ and fourth‐generation drugs was statistically significant (P = .0011). Of fourth‐generation fluoroquinolone infections, 0.015% (1/6651) and 0.1% (6/5915) were associated with gatifloxacin and moxifloxacin, respectively. The difference between drugs was statistically significant (P = .040). CONCLUSIONS: The differences in the pharmacokinetic and pharmacodynamic properties of quinolone antibiotics may affect the endophthalmitis incidence after cataract surgery. The significant difference in endophthalmitis rates between gatifloxacin and moxifloxacin requires further study.

Small-incision lenticule extraction

UNLABELLED This review looks at the benefits, limitations, complications, and future applications of the small-incision lenticule extraction procedure. Using the search terms small incision lenticule extraction and femtosecond lenticule extraction, we obtained data from 56 articles (omitting German and Chinese articles) from the PubMed database. Small-incision lenticule extraction has shown efficacy, predictability, and safety that are proportionate to those of laser in situ keratomileusis (LASIK), with the additional benefit that it eliminates flap creation and the attendant risks. The potential advantages of the procedure related to improved biomechanical stability, postoperative inflammation, and dry-eye symptoms have not been fully established. Small-incision lenticule extraction-treated eyes have shown a reduced degree of postoperative corneal denervation and higher-order aberrations and an accelerated rate of corneal nerve convalescence relative to LASIK. Future possibilities related to long-term cryogenic storage of extracted lenticules with eventual reimplantation or donation have been investigated with encouraging preliminary results. FINANCIAL DISCLOSURE Drs. Reinstein and Shah are consultants to Carl Zeiss Meditec AG. No author has a financial or proprietary interest in any material or method mentioned.

Artificial tears potpourri: a literature review

Numerous brands and types of artificial tears are available on the market for the treatment of dysfunctional tear syndrome. Past literature has focused on comparing the components of these products on patient’s clinical improvement. The wide array of products on the market presents challenges to both clinicians and patients when trying to choose between available tear replacement therapies. Different formulations affect patients based on etiology and severity of disease. In order to provide an unbiased comparison between available tear replacement therapies, we conducted a literature review of existing studies and National Institutes of Health clinical trials on commercially available, brand name artificial tears. Outcomes evaluated in each study, as well as the percent of patients showing clinical and symptomatic improvement, were analyzed. Fifty-one studies evaluating different brands of artificial tears, and their efficacy were identified. Out of the 51 studies, 18 were comparison studies testing brand name artificial tears directly against each other. Nearly all formulations of artificial tears provided significant benefit to patients with dysfunctional tear syndrome, but some proved superior to others. From the study data, a recommended treatment flowchart was derived.

Visual outcomes after wavefront-guided photorefractive keratectomy and wavefront-guided laser in situ keratomileusis: Prospective comparison

PURPOSE: To compare visual outcomes between wavefront‐guided photorefractive keratectomy (PRK) and wavefront‐guided laser in situ keratomileusis (LASIK). SETTING: Academic center, Salt Lake City, Utah, USA. METHODS: In this randomized prospective study, myopic eyes were treated with wavefront‐guided PRK and or wavefront‐guided LASIK using a Visx Star S4 CustomVue platform with iris registration. Primary outcome measures were uncorrected (UDVA) and corrected (CDVA) distance visual acuities and manifest refraction. Secondary outcome measures were higher‐order aberrations (HOAs) and contrast sensitivity. RESULTS: The PRK group comprised 101 eyes and the LASIK group, 102 eyes. At 6 months, the mean UDVA was −0.03 logMAR ± 0.10 [SD] (20/19) and 0.07 ± 0.09 logMAR (20/24), respectively (P = .544). In both groups, 75% eyes achieved a UDVA of 20/20 or better (P = .923); 77% of eyes in the PRK group and 88% in the LASIK group were within ±0.50 diopter of emmetropia (P = .760). There was no statistically significant difference between groups in contrast sensitivity at 3, 6, 12, or 18 cycles per degree. The mean postoperative HOA root mean square was 0.45 ± 0.13 μm in the PRK group and 0.59 ± 0.22 μm in the LASIK group (P = .012), representing an increase factor of 1.22 and 1.74, respectively. CONCLUSIONS: Wavefront‐guided PRK and wavefront‐guided LASIK had similar efficacy, predictability, safety, and contrast sensitivity; however, wavefront‐guided PRK induced statistically fewer HOAs than wavefront‐guided LASIK at 6 months. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Methicillin-resistant Staphylococcus aureus keratitis after laser in situ keratomileusis

A 50-year-old man had uneventful bilateral laser in situ keratomileusis (LASIK) for moderate myopia (-4.50 diopters sphere, both eyes). Twelve days postoperatively, he developed unilateral bacterial keratitis. Cultures revealed methicillin-resistant Staphylococcus aureus. The antibiotic regimen was adjusted, and he regained an uncorrected visual acuity of 20/40 and a best spectacle-corrected visual acuity (BSCVA) of 20/15. Bacterial keratitis after LASIK is a rare occurrence. Aggressive use of cultures and fortified antibiotics can prevent significant loss of BSCVA, even when a resistant organism is the cause.

Adipose-Derived Stem Cells on Hyaluronic Acid-Derived Scaffold A New Horizon in Bioengineered Cornea

OBJECTIVE To evaluate the ability of human adipose-derived stem cells (h-ASCs) to survive and differentiate in corneal stroma. METHODS Our experiment consisted of 2 phases. First, we cultured h-ASCs in different types of hyaluronic acid (HA)-derived synthetic extracellular matrixes (sECMs) to determine the capability of proliferation and survival of the cells in hydrogels. Second, h-ASCs were grown in plastic flasks, labeled with an intracytoplasmic membrane fluorescent molecule, transferred onto different types of sECMs or the native HA product, and then inserted into the corneal stroma of the rabbits. After 10 weeks, we assessed the viability of the stem cells and the expression of cornea-specific proteins. RESULTS The in vitro study showed that the HyStem-HP hydrogel had the highest yield of cells (1.1 × 10(6)/mL) compared with other types of HA-derived sECMs culture media, and the cells grown in the HyStem-HP hydrogel appeared more elongated and fibroblastlike. The in vivo study demonstrated that the labeled h-ASCs could be identified in the stroma with any type of sECM. The HA-derived sECMs, particularly the HyStem-HP hydrogel, showed better survival and cell morphologic features compared with pure HA. Immunostaining of keratocan, aldehyde dehydrogenase, and type I collagen revealed that the stem cells had expressed human cornea-specific proteins. CONCLUSION Human adipose-derived stem cells can be successfully grown on HA-derived sECMs in vivo and can express human cornea-specific proteins. CLINICAL RELEVANCE Human ASCs on an HA-derived scaffold may be used as a source of keratocytes to regenerate extracellular matrix-like material in situations where the cornea stroma has been compromised.

Femtosecond laser-assisted cataract surgery: A current review

To evaluate the safety, efficacy, advantages, and limitations of femtosecond laser-assisted cataract surgery through a review of the literature. A PubMed search was conducted using topic-appropriate keywords to screen and select articles. Initial research has shown appropriate safety and efficacy of femtosecond laser-assisted cataract surgery, with improvements in anterior capsulotomy, phacofragmentation, and corneal incision. Limitations of these studies include small sample size and short-term follow-up. Cost-benefit analysis has not yet been addressed. Preliminary data for femtosecond laser-assisted cataract surgery shows appropriate safety and efficacy, and possible advantage over conventional cataract surgery. Questions to eventually be answered include comparisons of long—term postoperative complication rates—including infection and visual outcomes-and analysis of contraindications and financial feasibility.

Bilateral explantation of Visian Implantable Collamer Lenses secondary to bilateral acute angle closure resulting from a non-pupillary block mechanism.

PURPOSE To report a case of bilateral non-pupillary block angle closure glaucoma after Visian Implantable Collamer Lens (ICL, STAAR Surgical) surgery. METHODS A 35-year-old woman with high myopia, white-to-white measurements of 11.8 mm in the right eye and 11.9 mm in the left eye, and anterior chamber depths >3 mm in both eyes underwent simultaneous bilateral ICL implantation with 13.2-mm lenses. RESULTS Persistent, bilateral acute angle closure developed despite multiple patent peripheral iridotomies and iridectomies. Visante anterior segment optical coherence tomography (AS-OCT, Carl Zeiss Meditec) revealed profound vaulting of the ICLs and angle closure. Both ICLs were explanted. After explantation, ultrasound biomicroscopy demonstrated a sulcus-to-sulcus diameter of 10.8 mm in the right eye and 11.2 mm in the left eye. CONCLUSIONS The correlation between white-to-white and sulcus-to-sulcus measurements were poor in this patient, resulting in extreme vaulting of the ICL and angle closure from a non-pupillary block mechanism. Proper identification of the mechanism of angle closure is aided by AS-OCT. For non-pupillary block mechanisms, ICL extraction is necessary.