Ladan Espandar

CATARACT SURGERY FOR THE DEVELOPING WORLD

Purpose of review To review surveys published within the last year concerning the prevalence of cataract blindness, rates of cataract surgical coverage and visual outcomes of cataract surgery in various developing countries, and to review recent studies that compare the different cataract surgical techniques used in developing countries. Recent findings Up to 75% of blindness (visual acuity below 20/400) is due to cataract. Cataract remains the most common treatable cause of blindness. Reported cataract surgical coverage is low, and visual outcomes are poor and necessitate improvement. Phacoemulsification is the preferred technique for cataract surgery in developed countries, but large-scale implementation in developing countries may prove to be a challenge. An alternative surgical technique, manual sutureless small incision extracapsular cataract surgery, has been increasing in popularity, as the technique has been shown to yield similar surgical outcomes as phacoemulsification. Summary Treating cataract blindness worldwide continues to be a formidable challenge. Significant barriers include cost, lack of population awareness, shortage of trained personnel and poor surgical outcomes. Both phacoemulsification and manual small incision extracapsular cataract surgery achieve excellent visual outcomes with low complication rates, but manual small incision extracapsular cataract surgery is significantly faster, less expensive and requires less technology. Therefore, manual small incision extracapsular cataract surgery may be the preferred technique for cataract surgery in the developing world.

Late In-the-Bag Spontaneous Intraocular Lens Dislocation: Evaluation of 86 Consecutive Cases

OBJECTIVE As techniques for cataract surgery have evolved, spontaneous intraocular lens (IOL) dislocation has decreased overall. However, since 2006 the Intermountain Ocular Research Center has received an increased number of explanted IOLs within the capsular bag forwarded for pathologic evaluation. Late, spontaneous dislocation of IOLs results from zonular insufficiency and zonulysis that has been associated with pseudoexfoliation, trauma, and other risk factors. The findings of 86 consecutive cases of this complication, analyzed in the laboratory, are described. DESIGN Retrospective case series. PARTICIPANTS Eighty-six IOLs explanted within the capsular bag, submitted in formalin. METHODS Standard light microscopy of specimens, as well as questionnaire sent to explanting surgeons and patient chart review, when available. MAIN OUTCOME MEASURES Lens design, material, and abnormalities; capsular bag anomalies; patient demographic data; surgical dates; and presence or absence of known risk factors. RESULTS This series included polymethyl methacrylate, silicone, and hydrophobic acrylic lenses, manufactured with both 1-piece and 3-piece designs. The mean time from surgery to spontaneous IOL dislocation was 8.5 years. The main conditions associated with the cases of IOL dislocation were as follows: pseudoexfoliation, 50%; prior vitreoretinal surgery, 19%; history of trauma, 6%; uveitis, 2%; and none or unknown, 23%. CONCLUSIONS Patients with any type of IOL are at risk for late in-the-bag dislocation. Pseudoexfoliation and vitreoretinal surgery were the most common associated conditions in this series. Regardless of the presence of known risk factors, IOLs dislocated on average 8.5 years after phacoemulsification and IOL implantation.

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.

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.

Effect of Iris Registration on Outcomes of LASIK for Myopia With the VISX CustomVue Platform

PURPOSE To compare visual outcomes after LASIK using the VISX STAR S4 CustomVue, with and without Iris Registration technology. METHODS In this retrospective study, LASIK was performed on 239 myopic eyes, with or without astigmatism, of 142 patients. Iris registration LASIK was performed on 121 eyes and non-iris registration LASIK was performed on 118 eyes. Primary outcome measures were uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and manifest refraction. RESULTS At 6 months, the mean values for UCVA (logMAR) were 0.00 +/- 0.09 in the iris registration group and -0.01 +/- 0.11 in the non-iris registration group (P = .587). Seventy-nine percent of eyes in the iris registration group had UCVA of 20/20 or better compared to 78% in the non-iris registration group (P = .518). Ninety-two percent of eyes in the iris registration group and 90% in the non-iris registration group were within +/- 0.50 diopters (D) of emmetropia (P = .999). Mean postoperative absolute change in total root-mean-square higher order aberrations in the iris registration group and non-iris registration group was 0.22 microm and 0.19 microm, respectively (P = .6). At 3 months, the mean magnitude of error of surgically induced astigmatism was -0.09 in the iris registration group and -0.04 in the non-iris registration group (P = .25). CONCLUSIONS Wavefront-guided LASIK with the VISX STAR S4 CustomVue laser system, independent of iris registration status, is effective, safe, and predictable. Under well-controlled surgical conditions, this study did not find any statistical significance supporting the better achievement of visual acuity, astigmatism correction, or the lesser induction of higher order aberrations using iris registration in comparison to a non-iris registration system.

Aquarium Coral Keratoconjunctivitis

Zoanthids are an excellent, lowmaintenance, fast-growing coral beloved by the marine aquarist (Figure 1). Despite their ease and beauty, zoanthids have specialized stinging cells called nematocysts, which are modified cells that inject a toxin for capturing prey or are released in response to stress or irritation. Some zoanthids produce palytoxin (PTX), one of the most deadly marine toxins. The toxic effects of PTX have been reported with dermal and ocular contact as well as inhalation exposure during cleaning of an aquarium or handling zoanthid colonies. In this article we report 2 cases of PTX-induced keratoconjunctivitis after the handling of zoanthid coral.

Prospective randomized trial of wavefront-guided laser in situ keratomileusis with the CustomCornea and CustomVue laser systems

PURPOSE: To compare visual function, safety, and higher‐order aberrations (HOAs) after wavefront‐guided laser in situ keratomileusis (LASIK) with the LadarVision CustomCornea (Alcon Laboratories, Inc.) and Star S4 CustomVue (Visx) laser systems. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: Seventy‐eight eyes of 39 patients with myopia with or without astigmatism were randomized for LASIK treatment in 1 eye with the CustomCornea laser; the other eye was treated with the CustomVue laser. Patients were followed for 6 months after surgery. The primary outcome measures were uncorrected visual acuity (UCVA), best spectacle‐corrected visual acuity (BSCVA), manifest refraction, and changes in HOAs. RESULTS: At 6 months, the mean logarithm of the minimum angle of resolution (logMAR) UCVA was −0.0135 ± 0.07 (SD) in the CustomVue group and 0.0417 ± 0.12 in the CustomCornea group (P = .023). Eighty‐eight percent of eyes in the CustomVue group had 20/20 or better UCVA compared with 67% in the CustomCornea group (P<.02). At 6 months, 91% of eyes in the CustomVue group and 79% in the CustomCornea group were within ±0.50 diopter (D) of emmetropia (P<.1); 88% and 50%, respectively, were within ±0.25 D (P<.001). Both platforms led to a small increase in total HOAs. The CustomVue system reduced trefoil and induced less of an increase in total HOAs, whereas the CustomCornea platform increased trefoil but induced less of an increase in spherical aberrations and coma. CONCLUSIONS: Both laser systems were effective, safe, and predictable. Wavefront‐guided LASIK with the CustomVue system resulted in better visual acuity, with more eyes having 20/20 acuity than in the CustomCornea group.

Ablation of lens epithelial cells with a laser photolysis system: Histopathology, ultrastructure, and immunochemistry

PURPOSE: To evaluate efficacy of a neodymium:YAG (Nd:YAG) laser photolysis system in removing lens epithelial cells (LECs) and characterize the effect of the laser on laminin and fibronectin involved in LEC adhesion and migration. METHODS: Cadaver eyes were evaluated using the Miyake technique. The lenses were removed with phacoemulsification. The modified Nd:YAG laser was used to clean the LECs from the capsule. Only the fornix was cleaned in some eyes and the anterior subcapsular area in other eyes. Some areas were not treated and acted as controls. Standard irrigation/aspiration (I/A) removal of LECs was performed in additional eyes. The eyes were analyzed using light microscopy and immunohistochemical staining. RESULTS: Histopathologic evaluation showed that the laser removed the LECs from the anterior lens capsule and from the fornix. Immunohistochemical staining showed fibronectin and laminin staining in the untreated areas that was absent in the treated areas. Standard I/A removal of the LECs showed absence of cells but persistent laminin and fibronectin. Electron microscopy showed epithelial cells in untreated areas with an absence of the LECs and debris in treated areas. CONCLUSIONS: The laser photolysis system removed LECs from the anterior lens capsule and capsule fornix. Along with the cells, laminin, fibronectin, and cell debris remained in the untreated areas but were removed by the treatment. This treatment may be useful in preventing posterior capsule opacification. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes.

Differentiation of Human Adipose-derived Stem Cells along the Keratocyte Lineage In vitro.

PURPOSE To evaluate differentiation of human adipose-derived stem cells (hASCs) to the keratocyte lineage by co-culture with primary keratocytes in vitro. MATERIALS AND METHODS A co-culture system using transwell inserts to grow hASCs on bottom and keratocytes on top in keratocyte differentiating medium (KDM) was developed. hASCs that were cultured in complete culture medium (CCM) and KDM were used as control. After 16 days, hASCs were examined for morphologic changes and proliferation by cell count. qRT-PCR and flow cytometry were used to detect the expression of aldehyde dehydrogenase 3 family, member A1 (ALDH3A1) and keratocan. RESULTS hASCs became more dendritic and elongated in co-culture system relative to CCM and KDM. The doubling time of the cells was longer as differentiation progressed. qRT-PCR showed a definite trend towards increased expression of both ALDH3A1 and keratocan in co-culture system despite statistically non-significant p-values. Flow cytometry showed significantly increased protein levels of ALDH3A1 and keratocan in co-culture system relative to CCM group (p < 0.001) and even relative to KDM group (p < 0.001 for ALDH3A1 and p < 0.01 for keratocan). CONCLUSION The co-culture method is a promising approach to induce differentiation of stem cell populations prior to in vivo applications. This study reveals an important potential for bioengineering of corneal tissue using autologous multi-potential stem cells.

Descemet stripping automated endothelial keratoplasty using donor corneas with previous laser in situ keratomileusis or photorefractive keratectomy: a case series and donor cap histopathology.

Purpose: To report outcomes in Descemet stripping automated endothelial keratoplasty (DSAEK) using donor tissue from eyes that have had previous refractive surgery and to report histopathology of the donor free cap. Methods: Retrospective case series. Preoperative and postoperative data were collected on each patient, and donor information was collected. Histopathologic evaluation was carried out on donor caps to determine the stability of the laser in situ keratomileusis (LASIK) flap and smoothness of the microkeratome cut during preparation of the donor. Results: DSAEK was performed on 7 eyes using donors that had undergone photorefractive keratectomy (PRK) or LASIK. One patient received PRK donor tissue, had no interface haze, and had improvement in vision. All but one patient who received LASIK donor tissue had improvement in vision, and that patient had severe graft folds noted intraoperatively that persisted. Histopathologic examination of 3 donor caps showed mild to moderate dehiscence of the LASIK flap, but the cut interface was consistent with normal donor tissue preparation histopathology. Conclusions: We report the first case of DSAEK using PRK donor tissue, which was successful. Our experience with LASIK donor tissue was comparable to nonrefractive donor tissue with the exception of the persistent donor macrofolds in one patient.