Comparison of keratocyte density after femtosecond laser vs mechanical microkeratome from 3 months up to 5 years after LASIK.

BACKGROUND: To compare keratocyte density after mechanical microkeratome LASIK (MK-LASIK) and femtosecond-laser assisted LASIK (FS-LASIK). METHODS: We performed a prospective study of myopic patients that underwent MK-LASIK or FS-LASIK. We measured keratocyte density 3 and 15 months, and 3-5 years after the surgery using confocal microscopy, and compared them with healthy, non-operated corneas. RESULTS: Thirty-one eyes were included in the FS-LASIK group, 30 in the MK-LASIK group and 28 in the control group. Three months postoperatively, there was an increase in the keratocyte population of the whole cornea, mainly due to the mid and posterior stromal layers, in both treatment groups. It was also increased in the stromal bed after MK-LASIK, but not after FS-LASIK. In both groups, this was followed by a normalisation and stabilisation of cell density in those deeper layers 15 months after the surgery. Keratocyte density in the flap and stromal bed was decreased 15 months after FS- and MK-LASIK compared to 3 months postoperatively and compared to controls. It seemed to remain stable thereafter. In spite of this decrease, the average cell density throughout the cornea was not decreased compared to controls at any time point. CONCLUSION: We found a reorganization of keratocytes density after LASIK, with an initial increase, followed by a decrease in the stromal flap and stromal bed 15 months postoperatively, and stable from then onwards, but still maintaining normal average densities in the total cornea. There were no differences between MK- and FS-LASIK.

Comparison of repeat penetrating keratoplasty, DSAEK and DMEK for the management of endothelial failure of previous PK.

PURPOSE: To compare the clinical outcomes of repeat PK, DSAEK-on-PK or DMEK-on-PK for the management of endothelial failure of previous penetrating keratoplasty. DESIGN: Retrospective, interventional consecutive case series. PARTICIPANTS: 104 consecutive eyes of 100 patients requiring a second keratoplasty for endothelial failure of their primary penetrating keratoplasty performed between September 2016 and December 2020. INTERVENTION: Repeat keratoplasty. MAIN OUTCOME MEASURES: Survival and visual acuity at 12 and 24 months, rebubbling rate and complications. RESULTS: Repeat PK was performed in 61/104 eyes (58.7%), DSAEK-on-PK was performed in 21/104 eyes (20.2%) and DMEK-on-PK was performed in 22/104 eyes (21.2%). Failure rates in the first 12 and 24 months were 6.6% and 20.6% for repeat PKs compared to 19% and 30.6% for DSAEK and 36.4% and 41.3% for DMEK. For those grafts surviving 12 months, the chances of surviving to 24 months were greatest for DMEK-on-PK at 92% vs 85% each for redo PK and DSAEK-on-PK. Visual acuity at one year was logMAR 0.53 ± 0.51 in the redo PK group, 0.25 ± 0.17 for DSAEK-on-PK and 0.30 ± 0.38 for DMEK-on-PK. 24-month outcomes were 0.34 ± 0.28, 0.08 ± 0.16, and 0.36 ± 0.36 respectively. CONCLUSIONS: DMEK-on-PK has a greater failure rate in the first 12 months than DSAEK-on-PK which has a greater failure rate than redo PK. However, the 2-year survival rates in our series for those already surviving 12 months were greatest for DMEK-on-PK. There was no significant difference in visual acuity at 12 or 24 months. Careful patient selection is needed by experienced surgeons to determine which procedure to offer to patients.

Cytomegalovirus anterior uveitis and occlusive retinal vasculitis without retinitis in a patient on immunomodulatory therapy.

PURPOSE: To describe unusual clinical features and therapeutic management of a case of cytomegalovirus (CMV) ocular disease in a patient on immunomodulatory therapy. SETTING/VENUE: Moorfields Eye Hospital NHS Foundation Trust, London, UK. METHODS: Medical history, clinical findings, investigation results, and multimodal imaging were retrospectively collected. RESULTS: A 61-year-old, South-East Asian man, developed CMV-related endotheliitis and occlusive retinal vasculitis, diagnosed by wide-angle fluorescein angiography. No retinitis was present on the fundus examination. Suspicion of CMV etiology was based on anterior segment findings, especially the presence of coin-shaped endothelial lesions. The diagnosis was confirmed by aqueous polymerase chain reaction (PCR) analysis which was positive for CMV DNA. The combined use of topical and systemic valganciclovir resulted in significant improvement of the picture. CONCLUSIONS: CMV can manifest in the eye as occlusive retinal vasculitis without the presence of typical retinitis.

Clinical Outcomes of Descemet Membrane Endothelial Keratoplasty in Pseudophakic Eyes Compared With Triple-DMEK at 1-Year Follow-up.

PURPOSE: To compare the survival rate 1 year after Descemet membrane endothelial keratoplasty (DMEK) in pseudophakic eyes versus combined phacoemulsification and DMEK (triple-DMEK). METHODS: Retrospective, interventional, consecutive case series. From all DMEKs performed from January 1, 2017, to June 30, 2018, we selected those performed in pseudophakic eyes (pseudophakic DMEK) and those that underwent triple-DMEK. We compared the survival rate 1 year after surgery between both groups and between the Fuchs endothelial dystrophy (FED) cases in both groups, plus the FED cases versus the pseudophakic bullous keratopathy (PBK) cases in the pseudophakic DMEK group. Second, we compared rebubbling rates and the influence of the use of gas or corneal sutures on rebubbling and dislocation rates. RESULTS: A total of 329 eyes were included (218 eyes pseudophakic DMEK and 111 eyes triple-DMEK). The survival rate at 1 year was 79.8% and 90%, respectively (P = 0.03). When only FED cases were included (133 pseudophakic DMEK and 108 triple-DMEK), no significant difference was found (87.9% vs. 90.7%, P = 0.59). Within the pseudophakic DMEK group, the survival rate was higher in FED cases (87.8%) compared with PBK cases (66.6%) (P = 0.0001). Rebubbling rates were 21.1% (pseudophakic DMEK) and 17.1% (triple-DMEK) (P = 0.39). The use of gas versus air or placing corneal sutures did not seem to influence the rebubbling (P = 0.64 and P = 0.13, respectively) or dislocation rates (P = 0.71 and P = 0.53, respectively). CONCLUSIONS: In the FED cases, performing phacoemulsification before DMEK or doing a combined procedure did not seem to affect the rebubbling or survival rate up to 1 year postoperatively. PBK was associated with a higher failure rate compared with that of FED.

Long-Term Review of Penetrating Keratoplasty: A 20-Year Review in Asian Eyes.

PURPOSE: To review the long-term outcomes of optical, therapeutic and tectonic forms of penetrating keratoplasty over a 20-year period in Asian eyes. DESIGN: Prospective cohort study involving the Singapore Corneal Transplant Study (SCTS). METHODS: All penetrating keratoplasties (PK) performed at the Singapore National Eye Centre (SNEC) from January 1991 to December 2010 were analyzed using records from the computerized database of the SCTS. This database includes preoperative, intraoperative, and postoperative patient data and donor cornea data. Only primary grafts were included. Patient demographics, donor cornea source, indications for grafting, complications, graft survival rate, and causes of graft failure were analyzed. RESULTS: A total of 1,206 primary PKs were performed. The mean age of the patients was 55 years (range: <1-101 years). The overall corneal graft survival rates at 1, 5, 10, 15, and 20 years were 91%, 66.8%, 55.4%, 52%, and 44%, respectively. For optical grafts, pseudophakic bullous keratopathy, postinfectious corneal scarring and thinning and keratoconus were the most common diagnoses. Graft survival for optical grafts was significantly better than therapeutic and tectonic grafts at all time points. Multivariate analysis suggested that a younger donor cornea age and higher donor endothelial cell count are associated with better long-term graft survival for optical grafts. Irreversible allograft rejection and late endothelial failure accounted for more than 60% of graft failures. CONCLUSIONS: Graft survival decreased over time from 91% at 1 year to 44% at 20 years' follow-up. Allograft rejection and late endothelial failure accounted for more than 60% of graft failures.

Understanding the Dual Dilemma of Dry Eye and Glaucoma: An International Review.

Glaucoma-related ocular surface disease (G-OSD) is a significant, yet often underdiagnosed, ocular co-morbidity affecting 40% to 59% of glaucoma patients worldwide. Although the use of topical glaucoma medications represents a proven strategy to control the untoward effects of high intraocular pressure, this treatment can profoundly disrupt the homeostasis of the tear film. The cumulative effect of medications, preservatives, and excipients alter underlying cellular structures which results in tear film abnormalities and instability of the ocular surface. Furthermore, these chronic inflammatory changes have been shown to impact efficacy of glaucoma treatment, patient compliance with therapy and overall quality of life. The pathogenesis of G-OSD is multifactorial and involves a vicious self-perpetuating cycle of inflammatory cytokines and proteins. The diagnosis of such disease is based on similar tests used in assessing traditional dry eye, taking into consideration findings specific to this patient population. The hallmark of treatment for these patients is to minimize the ocular surface inflammatory response by choosing glaucoma therapies that spare the ocular surface such as preservative free formulations and initiating dry eye treatment early in the course of care. In summary, glaucoma affects millions of patients around the world and chronic use of topical glaucoma medications may negatively impact the patient's ocular surface, symptoms, and vision. Understanding the pathogenesis of G-OSD, recognizing its risk factors and incorporating diagnostic and therapeutic strategies that restore and maintain ocular surface homeostasis will result in improved care for our patients.

Comparison of visual results between laser-assisted subepithelial keratectomy and epipolis laser in situ keratomileusis to correct myopia and myopic astigmatism.

PURPOSE: To compare the visual results after laser-assisted subepithelial keratectomy (LASEK) and epipolis laser in situ keratomileusis (epi-LASIK) to correct myopia. DESIGN: Retrospective, interventional, nonrandomized comparative study. METHODS: Patients treated with LASEK to correct myopia < or = -9.00 diopters (D) were compared to age- and refraction-matched patients treated with epi-LASIK using the same excimer laser (Esiris; Schwind Eye Tech Solutions, Kleinostheim, Germany). The epithelial flap was replaced after the ablation in every case. The visual results after both procedures were compared at each postoperative visit (one day, one week, one and three months). RESULTS: Ninety-four consecutive eyes were included in the study (47 in each group), matched for age and refraction. The preoperative spherical manifest refraction was -3.98 +/- 2.40 D in the LASEK group and -3.95 +/- 2.40 D in the epi-LASIK group (P = .9) (range -0.50 to -9.00 D). The uncorrected visual acuity (UCVA) one day postoperatively was 0.7 +/- 0.2 and 0.5 +/- 0.2 (P < .001), and one week after surgery it was 0.8 +/- 0.2 and 0.7 +/- 0.2, respectively (P = .1). The difference was again statistically significant one month after surgery (0.94 +/- 0.1 after LASEK, 0.82 +/- 0.1 after epi-LASIK, P < .001), but not three months postoperatively (1.06 +/- 0.21 and 1.03 +/- 0.18, respectively, P = .1). UCVA was > or =1.0 in 78.7% of LASEK eyes and 65.9% of epi-LASIK eyes three months after surgery. At that moment, the safety indices were 0.99 +/- 0.1 after LASEK and 0.93 +/- 0.1 after epi-LASIK (P = .04). The efficacy indices were 0.97 +/- 0.1 and 0.89 +/- 0.1, respectively (P = .01). CONCLUSIONS: Our results suggest a faster visual rehabilitation and better safety and efficacy outcomes after LASEK compared to epi-LASIK with repositioning of the epithelial flap when correcting low to moderate myopia.

Stability of laser epithelial keratomileusis with and without mitomycin C performed to correct myopia in thin corneas: a 15-month follow-up.

PURPOSE: To study the stability of the refraction 15 months after myopic laser epithelial keratomileusis (LASEK) performed in thin corneas with and without adjuvant mitomycin C (MMC). DESIGN: Retrospective review. METHODS: One hundred and thirty-six consecutive eyes that had undergone LASEK to correct their myopia and that had a preoperative central corneal thickness (CCT) of <500 microm at Vissum Madrid, Spain, were included. Intraoperative MMC was applied when the ablation depth exceeded 50 microm (49 eyes). We compared the residual refraction between the three- and 15-month examinations to detect a possible myopic change that would suggest secondary corneal ectasia. RESULTS: Mean preoperative CCT +/- standard deviation (SD) was 484.4 +/- 11.8 microm (range, 440 to 499 microm). Mean CCT +/- SD three months after surgery was 417.9 +/- 32.1 microm (range, 339 to 473 microm). Mean preoperative spherical refraction +/- SD was -3.49 +/- 2.10 diopters (D). Mean preoperative cylinder +/- SD was -0.87 +/- 1.20 D. The mean residual sphere +/- SD was 0.15 +/- 0.40 D three months after surgery and 0.11 +/- 0.60 D 15 months after surgery (P = .45). The mean cylinder +/- SD was -0.13 +/- 0.30 D and -0.25 +/- 0.50 D, respectively (P = .06). Both the uncorrected visual acuity (UCVA) and the best-spectacle corrected visual acuity (BSCVA) showed statistically significant improvement on the 15-month examination (P = .01 and P = .0001, respectively). When analyzed separately, the subgroup treated with intraoperative MMC also showed stability of the refraction and a statistically significant improvement both in UCVA and in BSCVA. Topography showed no signs of ectasia in any case. CONCLUSIONS: Myopic LASEK performed on thin corneas, regardless of the use of intraoperative MMC, seems to obtain stable refractive results, with no sign of ectasia during a 15-month follow-up.

Comparison between LASEK with mitomycin C and LASIK for the correction of myopia of -7.00 to -13.75 D.

PURPOSE: To compare laser epithelial keratomileusis (LASEK) and LASIK for the correction of high myopia. METHODS: A prospective, single-masked study was conducted. Patients treated with LASEK to correct myopia > or = -7.00 diopters (D) (spherical equivalent manifest refraction) with a cylinder < or = -3.50 D (LASEK group) were compared to patients treated with LASIK (LASIK group) using the same excimer laser (Technolas 217C). Mitomycin C (MMC) 0.02% was applied for 1 minute in all LASEK-treated eyes. RESULTS: A total of 228 consecutive eyes were included in the study (114 in each group, matched for preoperative refraction). The mean preoperative spherical equivalent manifest refraction was -8.72 +/- 1.20 D in the LASEK group and -8.74 +/- 1.20 D in the LASIK group (range: -7.00 to -13.75 D) (P = .9). Uncorrected visual acuity (UCVA) was significantly lower in LASEK eyes 1, 7, and 30 days postoperatively (P = .0001 for each comparison). No significant differences were found at 3 months postoperatively in UCVA (P = .3), best spectacle-corrected visual acuity (BSCVA) (P = .2), or in the safety (P = .6) and efficacy (P = .8) indices. Uncorrected visual acuity was 1.0 or better in 34.2% of LASEK eyes and 44.7% of LASIK eyes. Spherical refraction was +0.25 +/- 0.6 D after LASEK and -0.06 +/- 0.5 D after LASIK (P = .0001). Sixty-eight percent of LASEK eyes and 79% of LASIK eyes were within +/- 0.50 D of intended refraction. No LASEK eye versus 7 LASIK eyes lost 2 lines of BSCVA. Eight LASEK eyes gained 2 or more lines of BSCVA versus 1 LASIK eye. CONCLUSIONS: Visual improvement after LASEK with intraoperative MMC was significantly slower than after LASIK. Visual outcomes (UCVA, BSCVA, and safety and efficacy indices) 3 months after surgery were similar with both techniques for the correction of high myopia. Ten percent more eyes after LASIK were within +/- 0.50 D of intended refraction.

Incidence of diffuse lamellar keratitis after laser in situ keratomileusis associated with the IntraLase 15 kHz femtosecond laser and Moria M2 microkeratome.

PURPOSE: To analyze the incidence of diffuse lamellar keratitis (DLK) after laser in situ keratomileusis (LASIK) performed with an IntraLase 15 kHz femtosecond laser (IntraLase, Corp.) or a Moria M2 mechanical microkeratome (Moria SA). SETTING: Vissum Madrid, Madrid, Spain. METHODS: This retrospective study compared the incidence of DLK in consecutive LASIK procedures performed with the IntraLase 15 kHz femtosecond laser (study group) or the Moria M2 microkeratome (control group). Two surgeons performed both types of surgeries (femtosecond laser and microkeratome) using the same excimer laser (Technolas 217, Bausch & Lomb). During the first week postoperatively, topical dexamethasone drops were applied 8 times daily in the femtosecond group and 4 times daily in the mechanical microkeratome group. RESULTS: A total of 2000 consecutive eyes were analyzed (1000 eyes in each group). Diffuse lamellar keratitis stage 2 developed in 1 patient in each group; DLK stage 3 developed in 4 patients in the study group and in no patient in the control group (P = .03). CONCLUSION: Despite more intense postoperative steroid treatment, DLK seemed to occur more frequently after LASIK performed with the IntraLase 15 kHz femtosecond laser than after LASIK performed with the Moria M2 microkeratome.

Influence of preoperative keratometry on refractive results after laser-assisted subepithelial keratectomy to correct myopia.

PURPOSE: To study the relationship between preoperative keratometry and residual spherical equivalent (SE) after myopic laser-assisted subepithelial keratectomy (LASEK). SETTING: Vissum Madrid, Madrid, Spain. METHODS: This retrospective study comprised 1149 consecutive eyes that had LASEK to correct myopia. The relationship between preoperative keratometry and the 3-month postoperative SE was analyzed by linear regression. The same analysis was performed in the first decile (percentile 10) with the flattest keratometry readings, in the decile with the steepest readings, and in the quartiles with the lowest and highest preoperative myopia. RESULTS: Preoperatively, the mean SE was -4.59 diopters (D) +/- 2.80 (SD) (range -0.25 to -13.00 D) and the mean keratometry, 44.20 +/- 1.60 D (range 39.00 to 49.00 D). Three months postoperatively, the mean SE was +0.05 +/- 0.50 D. There was a significant (P = .04), although weak (r2 = 0.003), correlation between the mean preoperative keratometry and residual SE. Linear regression showed a positive significant correlation within each decile. The correlation was weak in the decile with the flattest corneas (115 eyes) (r2 = 0.04, P = .04) and slightly stronger in the decile with the steepest corneas (115 eyes) (r2 = 0.1, P = .001) (ie, the steeper the cornea, the greater the overcorrection). There was a weak correlation in the group with higher preoperative myopia (r2 = 0.05, P = .0003) but no correlation in the lower myopia group (P = .3). CONCLUSION: Preoperative corneal curvature did not seem to influence the spherical refractive outcomes after myopic LASEK.

Comparative study of two silicone hydrogel contact lenses used as bandage contact lenses after LASEK.

PURPOSE: To evaluate two silicone hydrogel contact lens materials as continuous-wear bandage contact lenses after laser-assisted subepithelial keratomileusis (LASEK). METHODS: The inclusion criteria were myopia of -6.00 diopters (D) or less, astigmatism lower than -1.5 D, bilateral best-corrected visual acuity of 20/20 or better, and candidates for bilateral LASEK. The patients were randomized to be fitted with a Balafilcon A (PureVision) lens in one eye and Galyfilcon A (Acuvue Advance) in the fellow eye. Uncorrected visual acuity, corneal epithelial status, conjunctival and limbal hyperemia, lens movement, contact lens debris, and the responses to a subjective-comfort questionnaire were assessed postoperatively. The parameters were evaluated before and 1 and 5 days after the procedure. A paired Student's t-test and chi-square tests were used when appropriate. RESULTS: We analyzed 44 eyes of 22 consecutive patients who underwent LASEK to correct low-to-moderate myopia. The mean spherical equivalent was -3.25 +/- 2.36 D. There was no difference in conjunctival or limbal hyperemia, lens movement, uncorrected visual acuity, or epithelial healing between the two lenses at any visit. A significant difference was found in lens deposition and discomfort, which were greater with the PureVision lens 5 days postoperatively (p = 0.01 for both comparisons). CONCLUSIONS: PureVision and Acuvue Advance contact lenses seem to be useful as continuous wear bandage contact lenses. There is no major clinical difference between the lenses, although patients report greater comfort with Acuvue Advance.

Comparison between LASEK and LASIK for the correction of low myopia.

PURPOSE: To compare the refractive results of laser epithelial keratomileusis (LASEK) and laser in situ keratomileusis (LASIK) for the correction of low myopia. METHODS: A prospective, interventional, non-randomized, observer-masked study was performed of patients with myopia of < or = -2.50 diopters (D) (cylinder < or = 1.50 D) who had undergone either LASEK or LASIK. Refractive analysis was performed by a masked observer preoperatively and 1 day, 1 week, and 1 and 3 months postoperatively. RESULTS: Seventy-nine eyes that fulfilled the inclusion criteria in each group were included in the study. No statistically significant differences were noted in age, gender, or preoperative refractive error between groups. Postoperative uncorrected visual acuity (UCVA) was significantly lower in LASEK eyes 1 and 7 days postoperatively (P = .0001). At 1 and 3 months postoperatively, no significant differences were noted between the groups in UCVA (P = .07), but best spectacle-corrected visual acuity 3 months postoperatively was significantly better in LASEK eyes (P = .01). The refractive error was similar in both groups (P = .3). CONCLUSIONS: Visual improvement after LASEK for low myopia is significantly slower than after LASIK. Visual outcomes at 3 months postoperatively were similar with both techniques for the correction of low myopia.

Effect of mitomycin-C on the corneal endothelium during excimer laser surface ablation.

PURPOSE: To study the effects of mitomycin-C (MMC) on the corneal endothelium after surface ablation. METHODS: This prospective observer-masked study comprised 40 consecutive patients (80 eyes) scheduled to have laser-assisted subepithelial keratectomy (LASEK) to correct myopia. The patients were divided into 2 groups. Group 1 included 32 eyes in which the ablation depth was 50 mum or less and that received no MMC. Group 2 included 48 eyes in which the ablation depth exceeded 50 mum and were treated with intraoperative MMC 0.02% for 30 seconds over the ablated zone. Preoperatively and 3 months postoperatively, 3 photographs of the central cornea of each eye were obtained using specular microscopy. A masked observer evaluated the endothelial cell density and compared the results between groups and the preoperative versus the postoperative results within the same group. RESULTS: The mean patient age was 31.5 years +/- 4.6 (SD) in Group 1 and 33.2 +/- 7.9 years in Group 2 (P = .3). Within-group comparison between the preoperative and postoperative endothelial cell density values showed a statistically significant increase in both groups. The mean values in Group 1 were 2462.5 +/- 226.8 cells/mm(2) preoperatively and 2562.5 +/- 258.7 cells/mm(2) postoperatively (P = .0001). The means in Group 2 were 2466.6 +/- 294.1 cells/mm(2) and 2525 +/- 312.5 cells/mm(2), respectively (P = .0008). The differences in endothelial cell counts between Group 1 and Group 2 preoperatively and postoperatively were not statistically significant (P = .9 and P =.5, respectively). CONCLUSION: A single intraoperative application of MMC 0.02% for 30 seconds after laser surface ablation did not seem to cause a substantial change in corneal endothelial cell density.

Learning curve of laser-assisted subepithelial keratectomy: influence on visual and refractive results.

PURPOSE: To study the effect of the learning curve of laser-assisted subepithelial keratectomy (LASEK) on the visual and refractive results. METHODS: This retrospective study comprised 56 eyes that had LASEK for myopia. The eyes were among the first 143 that had LASEK by the same surgeon with the same excimer laser and same nomogram. The 56 eyes were separated into 2 groups. Group 1 included the first 28 eyes to have LASEK by the surgeon. Group 2 comprised the last 28 eyes in the series whose refractive error could be matched with that in Group 1. The outcomes in the 2 groups were compared. RESULTS: The mean preoperative spherical refraction was -3.90 diopters (D) +/- 1.90 (SD) in Group 1 and -3.70 +/- 2.53 D in Group 2 (P = .2). There were no significant differences in preoperative cylinder or best spectacle-corrected visual acuity (BSCVA) between groups. The postoperative uncorrected visual acuity (UCVA) was significantly worse in Group 1 on 1 day and 7 days postoperatively (P = .02 and P = .03, respectively); there was no significant difference at 1 month and 3 months. The safety index (postoperative BSCVA/preoperative BSCVA) and efficacy index (postoperative UCVA/preoperative BSCVA) were better in Group 2, although the difference was not statistically significant. The spherical refraction 3 months postoperatively was +0.50 +/- 0.83 D in Group 1 and +0.10 +/- 0.27 D in Group 2 (P = .02); 75.00% of eyes and 96.42% of eyes, respectively, were within +/-0.50 D of the intended correction (P = .01). Seven percent of eyes in Group 1 and no eye in Group 2 lost 2 or more lines of BSCVA. CONCLUSIONS: Results indicate that the outcomes of LASEK depend on surgeon experience. Thus, caution is advised when interpreting LASEK results without knowing the surgeon's level of experience.

Idiopathic stromal keratitis resembling central toxic keratopathy.

UNLABELLED: A 28-year-old previously emmetropic woman presented with a 2-day history of bilateral photophobia and blurred vision. She had no history of corneal surgery or contact lens use. Snellen uncorrected distance visual acuity (UDVA) was 6/12 bilaterally. Bilateral anterior stromal infiltration of the central cornea was seen, with no overlying epithelial defect and intact sensation. There was a marked hyperopic shift, central corneal thinning, and associated keratometric flattening. The patient was started on topical corticosteroids. Over 12 weeks, the UDVA returned to 6/5 with emmetropization of the refractive status and thickening of the central cornea. The clinical findings in our patient resemble those of central toxic keratopathy (CTK) in post-refractive-surgery cases, suggesting a similar mechanism. To our knowledge, this is the first report of a patient presenting with a CTK-like syndrome in the absence of previous keratorefractive surgery or contact lens use. The pathophysiology of this condition remains elusive and requires further investigation. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Intraoperative anterior segment optical coherence tomography: a novel assessment tool during deep anterior lamellar keratoplasty.

PURPOSE: To describe the use of high-resolution anterior segment optical coherence tomography (AS-OCT) during deep anterior lamellar keratoplasty (DALK). DESIGN: Prospective case series. METHODS: At the Singapore National Eye Centre we performed sequential intraoperative AS-OCT scans using iVue 100-2 (Optovue, Fremont, CA, USA) during various DALK techniques. RESULTS: In case 1 (corneal scarring) the OCT images helped to guide manual dissection, showed the depth of the needle track before air injection, and identified the location of a small bubble when the big bubble failed. In cases 2 (macular dystrophy) and 3 (lattice), viscodissection was undertaken, but in case 2 the OCT showed the viscoelastic trapped intrastromally, compared to case 3, in which the viscobubble dissection was successful. In case 4 (irregular corneal thinning and scarring), AS-OCT enabled accurate decision on initial trephination and guided dissection. In case 5 (keratoconus), the OCT showed the achieved big-bubble and detached Descemet membrane. Case 6 was a repeat DALK; the OCT guided the manual dissection of the residual stroma underlying the failed graft. In case 7, the OCT showed an intrastromal retention of fluid that was not detectable by the operating microscope due to diffuse scarring following alkaline injury. The OCT helped to assess the location of the Descemet membrane and guided the manual dissection. CONCLUSIONS: Intraoperative high-definition AS-OCT obtained good-quality images of the cornea during DALK and proved useful in various cases of DALK to help the surgeon decide on a number of surgical steps.