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PURPOSE The aim of this study was to evaluate and compare early corneal biomechanical changes after small-incision lenticule extraction (SMILE) and photorefractive keratectomy (PRK). METHODS The study comprised 74 patients eligible for refractive surgery, equally allocated to PRK (37 patients) and SMILE (37 patients). Corneal biomechanical properties were recorded and compared between the 2 groups at preoperatively and 3 months after surgery using a dynamic ultra-high-speed Scheimpflug camera equipped with a noncontact tonometer. RESULTS Both procedures significantly affected corneal biomechanical properties at 3 months after surgery. Patients in the PRK group showed significantly better results for deformation amplitude ratio (DA ratio) (P = 0.03), maximum inverse radius (InvRadMax) (P = 0.02), and A2 time (P = 0.03). The mean changes in DA ratio, HC radius, InvRadMax, and Ambrosio relational thickness were significantly higher in the SMILE group in comparison with those of the PRK group (all, P < 0.05). In both groups, change in CCT was significantly correlated with changes in DA ratio and InvRadMax (P < 0.05). CONCLUSIONSS Both SMILE and PRK refractive surgeries significantly altered corneal biomechanical properties but the changes were more prominent after SMILE.

The purpose of this study was to assess the repeatability and agreement of horizontal white-to-white (WTW) measurements using 4 different imaging modalities including a slit-scanning elevation topographer, dual rotating Scheimpflug camera and Placido Disc tomographer, Placido Disc topographer, and anterior segment optical coherence (OCT) tomographer.In this prospective study, 33 eyes of 33 healthy subjects were scanned 3 times using each of the Orbscan IIz, Sirius, Nidek OPD III, and DRI OCT Triton devices and WTW measurements were recorded. Repeatability was assessed using the intraclass correlation coefficient (ICC), and agreement was analyzed using Bland-Altman plots.Mean WTW values obtained from the Orbscan IIz, Sirius, Nidek, and DRI OCT Triton devices were 11.76 ± 0.41, 12.10 ± 0.45, 12.14 ± 0.41, and 12.40 ± 0.48 mm, respectively. Overall, there was high repeatability, with the ICC0.86 for all devices. The Sirius showed the highest repeatability (ICC = 0.993), and the Nidek the lowest (ICC = 0.870). All pairwise comparison showed significant differences in the mean WTW measurements ( P0.01) except between Sirius and Nidek ( P = 0.27). Mean differences showed that the DRI OCT Triton had the highest WTW values, followed by Nidek, Sirius, and finally by Orbscan, which provided the lowest measurements. All pairwise comparisons had wide limits of agreements (between 0.60 and 0.80 mm).In healthy subjects the 4 devices demonstrated high repeatability in WTW measurement. However, a poor agreement between the devices suggests that they should not be used interchangeably for WTW measurements in clinical practice.

PURPOSE To compare the biomechanical properties of the cornea after epithelial removal in eyes with keratoconus undergoing corneal cross-linking. METHODS Prospective interventional case series at a university hospital tertiary referral center. Corneal biomechanical properties were measured in patients with keratoconus undergoing corneal cross-linking, immediately before and after epithelial debridement by using a dynamic ultrahigh-speed Scheimpflug camera equipped with a noncontact tonometer. RESULTS The study comprised 45 eyes of 45 patients with a mean age of 19.6 ± 4.9 years (range 14-34). The cornea was found to be 23.7 ± 15.7 μm thinner after epithelial removal (P < 0.01). Corneal stiffness was reduced after epithelial removal as demonstrated by a significant decrease of parameters such as stiffness parameter A1 (12.31, P < 0.01), stiffness parameter-highest concavity (2.25, P < 0.01), A1 length (0.13 mm, P = 0.04), highest concavity radius of curvature (0.26 mm, P = 0.01), highest concavity time (0.22 ms, P = 0.04) and an increase in A1 velocity (-0.01 m/s, P = 0.01), A1 deformation amplitude (-0.03 mm, P ≤ 0.01), A1 deflection length (-0.32 mm, P < 0.01), A2 deformation amplitude (-0.03 mm, P = 0.01), and A2 deflection length (-1.00 mm, P < 0.01). There were no significant differences in biomechanical intraocular pressure (0.15 mm Hg, P = 0.78), deformation amplitude (0.03, P = 0.54), maximum inverse radius (-0.01 mm, P = 0.57), and whole eye movement length (-0.02 mm, P = 0.12). CONCLUSIONS Dynamic ultrahigh-speed Scheimpflug camera equipped with a noncontact tonometer offers an alternative method for in vivo measurements of the epithelial layer's contribution to corneal biomechanical properties. Our results suggest that corneal epithelium may play a more significant role in corneal biomechanical properties in patients with keratoconus than previously described.

PURPOSE To review indications and clinical results for a hybrid deep lamellar endothelial keratoplasty (Femto-DLEK) technique combining contemporary donor tissue preparation and implantation techniques with femtosecond laser-assisted dissection of the host tissue. METHODS A retrospective analysis of consecutive cases of Femto-DLEK performed between 2011 and 2014 at Moorfields Eye Hospital, London, was conducted. All patients underwent manifest refraction and optical coherence tomography examination at their most recent review visit. Secondary interventions, graft rejection, and graft failure were recorded alongside corrected distance visual acuity. RESULTS Femto-DLEK was performed in 7 eyes of 7 cases. Mean postoperative follow-up duration was 19 months. Indications included revision of deep anterior lamellar keratoplasty (n = 4), revision of failed Descemet stripping endothelial keratoplasty in cases with an anterior chamber intraocular lens (n = 2), and primary surgery in cases of dense posterior stromal copper deposition. All corneas were recorded as clear by 6 weeks after surgery. Median (range) preoperative corrected distance visual acuity was 6/60 (6/9-1/60), which improved to 6/9 (6/6-6/24) at final review. Tissue bridges requiring significant additional manual lamellar dissection were present in all 4 cases in which deep stromal femtosecond laser lamellar dissection was performed. Femtosecond laser host dissection in the remaining cases was restricted to only a posterior side-cut. CONCLUSIONS Femto-DLEK is a useful alternative endothelial keratoplasty modality for a narrow range of indications. The femtolaser posterior side-cut facilitates DLEK, but further development of the Femto-DLEK technique is required to optimize the combination with deep lamellar host dissection.

PURPOSE To report spontaneous corneal clearing with improved visual acuity and central endothelial cell repopulation after the removal of a dislocated donor button following Descemet stripping endothelial keratoplasty (DSEK). METHODS Interventional case report. RESULTS An 84-year-old woman with decreased visual acuity in the right eye secondary to Fuchs endothelial dystrophy and cataract underwent combined cataract extraction, intraocular lens implantation, and DSEK. After primary graft failure, the resulting detached, opaque, and retracted donor lenticule was removed from the eye 2 months after the initial surgery and not replaced. The cornea started to clear after the donor button removal with central endothelial cell repopulation. CONCLUSIONS Corneal deturgescence is not strictly dependent on donor lenticule adhesion to the host posterior stromal surface. Endothelial cell migration and repopulation of the central cornea can occur after DSEK and after the removal of the failed endothelial graft, with corneal clearing and improved visual outcomes.

PURPOSE Corneal transplantation is the most commonly performed tissue transplantation boasting over a century of history, science, and tradition. One of the most promising immunomodulatory substances whose immunosuppressive effect has revolutionized solid organ transplantation is cyclosporine (CsA). We present a literature review on the role of topical cyclosporine in corneal transplantation. METHODS A review of the published literature using key databases that include MEDLINE and PubMed was undertaken. Published evidence base for the use of topical cyclosporine in corneal transplantation between 1986 and 2010 was evaluated and summarized. RESULTS There is some scientific evidence to support the use of topical cyclosporine in appropriately selected cases of corneal transplantation. Although some encouraging human case series and case-control studies have been published, to date most randomized controlled trials evaluating the effects of topical cyclosporine in graft rejection prophylaxis and treatment have failed to demonstrate statistically significant improved outcomes. CONCLUSIONS Cyclosporine cannot currently be considered as an effective sole agent in prophylaxis and treatment of allograft rejection, and corticosteroids therefore remain the gold standard choice of therapy. Further studies are required to refine the role of cyclosporine in modern corneal transplantation.

To determine the incidence of clinical keratoconus (KCN) in an Iranian population.This prospective surveillance study was conducted in Yazd province in central Iran (population 990,818). During 1 year (July 2008 to June 2009), all new patients with KCN were registered and referred. Diagnosis was based on the topographic pattern, and indices were measured and eye examination was done by anterior segment subspecialists.Of the 564 eligible patients referred, 28 did not attend their topography session (95% response rate). Topographic figures showed suspect or definite patterns of KCN in 47.8% of participants (256/536 subjects). Based on topographic images and clinical examination, KCN was confirmed in 221 patients, and in addition, 26 patients were categorized as having suspected KCN and 9 had non-KCN corneal diseases; therefore, the annual incidence rate of KCN was estimated as 22.3 (95% confidence interval, 19.5-25.4) and 24.9 (95% confidence interval, 21.9-28.2) per 100,000 population, excluding and including suspected KCN cases, respectively.The incidence of KCN in our context is apparent and comparable with rates in other studies on Asian ethnic populations. This is much higher than the incidence in European Caucasians and warrants further genetic and environmental studies.