Descemetic and predescemetic DALK in keratoconus patients: a clinical and confocal perspective study.

PURPOSE: To evaluate the clinical outcomes and in vivo confocal microscopy (IVCM) features of keratoconus patients who underwent deep anterior lamellar keratoplasty (DALK). METHODS: DALK was performed using the big bubble technique in all the patients. If the bubble was not successful to bare the descemet membrane, a manual dissection layer-by layer was performed to expose a deep stromal plane close to the DM. The patients were divided in two groups depending on the intraoperative baring of the descemet membrane: predescemetic DALK (PD-DALK) and descemetic DALK (D-DALK) group. RESULTS: One month after surgery the D-DALK patients show an increase of mean BCVA. In the PD-DALK group mean BCVA did not show significant improvement as compared to preoperative values. At 6 months after surgery mean BCVA was found to be similar in both groups. At 1 month IVCM the peak of reflectivity of the interface was lower in D-DALK group compared to PD-DALK. At 6 months the values of reflectivity were comparable. CONCLUSIONS: At 1 month D-DALK seems to lead to a minor interface reflectivity and to a better BCVA; these differences disappear after 6 months and the values of interface reflectivity and BCVA are comparable between D-DALK and PD-DALK.

Influence of disc size on optic nerve head versus retinal nerve fiber layer assessment for diagnosing glaucoma.

PURPOSE: To explore and compare the influence of optic disc size on the diagnostic accuracy of retinal nerve fiber layer (RNFL) thickness and optic nerve head (ONH) quantitative assessment. DESIGN: Observational, cross-sectional evaluation of diagnostic tests. PARTICIPANTS: We included 120 eyes from 50 normal subjects and 70 glaucomatous patients classified by the presence of a repeatable visual field defect for the analysis. TESTING: The RNFL thickness was measured by scanning laser polarimetry with variable corneal compensator (GDx-VCC, Carl-Zeiss Meditec, Dublin, CA) and spectral-domain optical coherence tomography (Cirrus HD-OCT, Carl Zeiss Meditec, Inc). We obtained ONH imaging by means of confocal scanning laser ophthalmoscopy (HRT3; Heidelberg Engineering, GmbH, Dossenheim, Germany). MAIN OUTCOME MEASURES: Sensitivity and specificity for normative classifications, sensitivity at fixed specificity and area under the receiver operating characteristics curve (AUC) for continuous parameters. A logistic marginal regression model and coefficients of variation (CoV) have been used to test and quantify the influence of optic disc size on the diagnostic accuracy of the 3 technologies under investigation. RESULTS: Among continuous parameters average RNFL thickness for Cirrus HD-OCT, nerve fiber indicator for GDx-VCC and cup shape measure for the HRT3 showed the best diagnostic accuracy with an AUC of 0.97, 0.94, and 0.94, respectively. Among normative classifications, the highest sensitivity and specificity were found for OCT average RNFL thickness (75.8% and 94.7%), for GDx superior thickness (77.1% and 97.5%), for HRT3 Moorfields regression analysis result (89.4% and 73.7%) and for HRT3 GPS global (92.3% and 76.5%). The diagnostic performance of HRT3 parameters seemed to be significantly influenced by optic disc size, although the same was not true for Cirrus HD-OCT and GDx VCC. The most steady performers for each imaging device across disc size groups were Cirrus HD-OCT average thickness (CoV, 1.6%), GDx-VCC inferior thickness (CoV, 2.5%), and HRT3 GPS temporal and nasal (CoV, 21.4%). CONCLUSIONS: The diagnostic accuracy of quantitative RNFL assessment as performed by Cirrus HD-OCT and GDx-VCC is high and virtually unaffected or only minimally affected by the size of the optic disc and may provide more consistent diagnostic outcomes across small and large discs than ONH assessment as performed by HRT3.

Evaluation of molecular markers in corneal regeneration by means of autologous cultures of limbal cells and keratoplasty.

PURPOSE: To determine the epithelial phenotype in patients with a limbal stem cell deficiency (LSCD) after ocular surface reconstruction with autologous cultured stem cells. To correlate the epithelial phenotype with the clinical outcome. METHODS: Six eyes affected by LSCD, verified and graded by impression cytology, were treated with an autologous fibrin-cultured limbal stem cell graft. The clinical outcome was defined as a "success" or a "failure," depending on ocular surface stability. To improve their visual function, 4 patients underwent lamellar or penetrating keratoplasty after the stem cell graft. The phenotype of the regenerated corneal epithelium was determined by immunofluorescence of the corneal button to detect CK12, CK3, CK19, and Muc1 as corneal and conjunctival markers. RESULTS: After a mean follow-up of 24 months, 5 cases were defined as successes; 1 case presented an epithelial defect 4 months after grafting and was defined as a failure. Immunofluorescence performed on 4 patients after lamellar and penetrating keratoplasty confirmed the presence of epithelial corneal markers (CK12 and CK3) in 2 of the success cases and the presence of conjunctival markers (CK19 and Muc1) in the 1 failure case. In one of the success cases, both corneal and conjunctival markers were detected on the corneal button. All success cases showed maintenance of marker accounting for high proliferative potential (DeltaNp63alpha) after transplantation. CONCLUSIONS: Autologous cultures of limbal stem cells can regenerate a functional corneal epithelium in patients affected by unilateral LSCD. We showed a correlation between the clinical outcome and the molecular marker expression.

Pre-cut donor tissue for Descemet stripping automated keratoplasty: anterior hinged lamella on versus off.

AIMS: To compare two different techniques for preparation of pre-cut lamellar corneal tissue for Descemet stripping automated keratoplasty. BACKGROUND/METHODS: Eight donor lenticules were created with a full pass of the microkeratome blade, which resulted in a posterior lamella and a free cap (anterior lamella off group (AL-off)). Contralateral donor lenticules were created with an incomplete pass of the microkeratome blade, which resulted in a posterior lamella and a hinged anterior cap (anterior lamella on group (AL-on)). Endothelial cell density, cellular viability and corneal thickness were evaluated before dissection, and 4 and 24 h after dissection. RESULTS: Average pre-cut endothelial cell density was 2552.25 (+/-105) and 2572.25 (+/-110) cells/mm(2) in the AL-off group and AL-on group, respectively (p=0.7). At 24 h cell density was 2404.87 (+/-74) in the AL-off group (p<0.01) and 2368.74 (+/-148) in the AL-on group (p=0.01). The mean percentage of trypan blue-stained cells was consistently higher in the hinged AL-on group. Corneal thickness increased by approximately 20% in both groups after 24 h cold storage. CONCLUSION: Eye bank-prepared tissue offers the potential advantage of being screened for mechanical stress damage occurring during the automated dissection.