Bremsstrahlung Dose Rate Kernels in Tissue.

ABSTRACT: Radionuclides emitting high-energy beta rays are frequently employed for therapeutic purposes in the field of medicine. However, it is widely recognized that such radionuclides have the potential to generate in vivo bremsstrahlung radiation. This research study focused on investigating the dose rate of bremsstrahlung radiation emanating from a radioactive source embedded in a patient. To accomplish this, we estimate the spectral energy distribution of the generated bremsstrahlung. By employing this spectral distribution, we present a novel method for estimating the bremsstrahlung dose rate kernel applicable to a given combination of source and material. This method considers photon buildup and attenuation, as well as the encapsulation of the radiation source. Furthermore, we provide formulas for both monoenergetic electrons and beta-transition electrons that account for radioactive decay.

Estimation of absorbed radiation doses to skin and S-values for organs at risk due to nasal administration of PET agents using Monte Carlo simulations.

PURPOSE: The intranasal (IN) administration of radiopharmaceuticals is of interest in being a viable route for the delivery of radiopharmaceuticals that do not ordinarily cross the blood-brain barrier (BBB). However, to be viable in a patient population, good image quality as well as safety of the administration should be demonstrated. This work provides radiation dosimetry calculations and simulations related to the radiation safety of performing such experiments in a human cohort. METHODS: We performed Monte Carlo (MC) simulations to estimate radiation dose to the skin inside a cylindrical model of the nasal cavity assuming a homogenous distribution layer of 11 C and 18 F and calculated a geometry conversion factor (FP-C ) which can be used to convert from a planar geometry to a cylindrical geometry using more widely available software tools. We compared radiation doses from our simulated cylindrical geometry with the planar dose estimates employing our geometry conversion factor from VARSKIN 6.1 software and also from an analytical equation. Furthermore, in order to estimate radiation dosimetry to surrounding organs of interest, we performed a voxelized MC simulation of a fixed radioactivity inside the nasal cavity and calculated S-values to organs such as the eyes, thyroid, and brain. RESULTS: MC simulations of contamination scenarios using planar absorbed doses of 15.50 and 8.60 mGy/MBq for 18 F and 11 C, respectively, and 35.70 and 19.80 mGy/MBq per hour for cylindrical geometries, leading to determination of an FP-C of 2.3. Planar absorbed doses (also in units of mGy/MBq) determined by the analytical equation were 16.96 and 8.68 (18 F and 11 C) and using VARSKIN were 16.60 and 9.26 (18 F and 11 C), respectively. Application of FP-C to these results demonstrates values with a maximum difference of 9.41% from the cylindrical geometry MC calculation, demonstrating that when accounting for geometry, more simplistic techniques can be utilized to estimate IN dosimetry. Voxelized MC simulations of radiation dosimetry from a fixed source of 1 MBq of activity confined to the nasal cavity resulted in S-values to the thyroid, eyes, and brain of 1.72 x 10-6 , 1.93 x 10-5 , and 3.51 x 10-6  mGy/MBq·s, respectively, for 18 F and 1.80 × 10-6 , 1.95 × 10-5 , and 3.54 × 10-6  mGy/MBq·s for 11 C. CONCLUSION: Dosimetry concerns about IN administrations of PET radiotracers should be considered before clinical use. Values presented in the simulations such as the S-values can be further used for assessment of absorbed doses in cases of IN administration, and can be used to develop and adapt specific study protocols. All three presented methods provided similar results when considering the use of a geometry conversion factor for planar to cylindrical geometry, demonstrating that standard tools rather than dedicate MC simulations may be used to perform dose calculations in nasal administrations.

A Novel Dominant Mutation in SAG, the Arrestin-1 Gene, Is a Common Cause of Retinitis Pigmentosa in Hispanic Families in the Southwestern United States.

Purpose: To identify the causes of autosomal dominant retinitis pigmentosa (adRP) in a cohort of families without mutations in known adRP genes and consequently to characterize a novel dominant-acting missense mutation in SAG. Methods: Patients underwent ophthalmologic testing and were screened for mutations using targeted-capture and whole-exome next-generation sequencing. Confirmation and additional screening were done by Sanger sequencing. Haplotypes segregating with the mutation were determined using short tandem repeat and single nucleotide variant polymorphisms. Genealogies were established by interviews of family members. Results: Eight families in a cohort of 300 adRP families, and four additional families, were found to have a novel heterozygous mutation in the SAG gene, c.440G>T; p.Cys147Phe. Patients exhibited symptoms of retinitis pigmentosa and none showed symptoms characteristic of Oguchi disease. All families are of Hispanic descent and most were ascertained in Texas or California. A single haplotype including the SAG mutation was identified in all families. The mutation dramatically alters a conserved amino acid, is extremely rare in global databases, and was not found in 4000+ exomes from Hispanic controls. Molecular modeling based on the crystal structure of bovine arrestin-1 predicts protein misfolding/instability. Conclusions: This is the first dominant-acting mutation identified in SAG, a founder mutation possibly originating in Mexico several centuries ago. The phenotype is clearly adRP and is distinct from the previously reported phenotypes of recessive null mutations, that is, Oguchi disease and recessive RP. The mutation accounts for 3% of the 300 families in the adRP Cohort and 36% of Hispanic families in this cohort.

Immediate endothelial cell loss after penetrating keratoplasty.

PURPOSE: To report the pattern and the extent of corneal endothelial cell loss immediately after a penetrating keratoplasty (PK) is performed. METHODS: Ten donor corneal-scleral tissues with healthy endothelium were used to perform 10 PK surgeries on cadaver eyes. An 8.25-mm donor graft was placed into an 8.00-mm trephinated recipient bed of the cadaver eye. A 10-0 nylon suture was used with a 16-interrupted suture closure technique to secure each donor button. Viscoelastic was used to protect the endothelium in every case. The corneal donor buttons were removed and stained using trypan blue and alizarin red dyes. Digital high-definition photographs were obtained to record the pattern and quantity of stain resulting from endothelial damage and cell loss. Percent endothelial loss was calculated using the digital planimetry of our previously described Adobe Photoshop technique. RESULTS: The immediate mean percent cell loss across the whole graft was 25.7% ± 7.5% (Range, 18-39). There was a distinct pattern of loss, with 58.3% of the loss in the peripheral 0.75 mm, and 12.4% of the loss in the central 3.00 mm. CONCLUSIONS: The immediate total endothelial cell loss after the PK was performed was about 25%. The immediate cell loss after the PK was consistent with areas of trephination and suture placement.

Endothelial keratoplasty: prospective, randomized, masked clinical trial comparing an injector with forceps for tissue insertion.

PURPOSE: To compare the complications and outcomes of Descemet stripping automated endothelial keratoplasty (DSAEK) when the tissue is either folded and inserted with a forceps or inserted using a platform injector device without folding. DESIGN: Prospective, randomized, masked clinical trial. METHODS: DSAEK was performed in 100 eyes of 79 patients undergoing DSAEK surgery for Fuchs corneal dystrophy. Fifty eyes were randomized to have the donor tissue inserted with Charlie II insertion forceps (Bausch & Lomb Surgical) and 50 eyes were randomized to have the donor tissue inserted with the Neusidl Corneal Inserter (Fischer Surgical Inc). All other steps of the surgical procedure were exactly the same. Surgical problems, postoperative complications, and central endothelial cell density at 6 months were recorded and then measured by a masked observer. The study's main outcome measures were total central endothelial cell density and percentage of donor endothelial cell loss from before surgery to 6 months after surgery and rate of complications (graft dislocation and primary graft failure). RESULTS: No primary graft failures occurred in either group and only 1 dislocation occurred in the series (Neusidl group). One late failure occurred at 6 months (Neusidl group). There was no difference in the preoperative endothelial cell density between the Neusidl and forceps groups, but there was a higher percentage of cell loss with the Neusidl group (33%) than with the forceps group (25%) at 6 months (P = .017). CONCLUSIONS: The Neusidl Corneal Inserter yielded a low immediate complication rate for DSAEK surgery for novice and experienced surgeons. Although still at an acceptable level, short-term endothelial survival was significantly worse after Neusidl tissue insertion than that after forceps tissue insertion.

In vitro evaluation of endothelial cell loss using the Neusidl Corneal Inserter.

PURPOSE: To determine the immediate endothelial cell loss (ECL) resulting from insertion of a precut donor button using the Neusidl Corneal Inserter (NCI) and compare it with the previously published ECL resulting from insertion of a folded donor button using non-coapting forceps. METHODS: Ten corneas were precut for Descemet stripping automated endothelial keratoplasty and trephinated to a diameter of 8.0 mm (n = 5) or 8.5 mm (n = 5). Each tissue was placed onto the platform of a new NCI spatula and inserted into a cadaveric whole globe through a 5.2 mm incision. The tissue was carefully removed and stained with trypan blue and alizarin red to detect damaged endothelium. ECL was estimated using Adobe Photoshop planimetry. Mean ECL was compared with previously reported studies of forceps insertion with a one-sample t test, using SPSS v. 19. Geographic patterns of ECL were also documented. RESULTS: Mean ECL was 15.6% (95% confidence interval, 13.8-17.4). We were unable to detect a difference in ECL compared with previous insertion methods studied (P < 0.001). The pattern of damage from the NCI was different than that previously seen with forceps insertion. CONCLUSION: Immediate endothelial damage resulting from use of the NCI for insertion of Descemet stripping automated endothelial keratoplasty tissue is comparable with that seen with a standard forceps technique, but with a different damage pattern.

"Ultrathin" DSAEK tissue prepared with a low-pulse energy, high-frequency femtosecond laser.

PURPOSE: To evaluate the endothelial cell survival and stromal bed quality when creating deep stromal cuts with a low-pulse energy, high-frequency femtosecond laser to produce "ultrathin" tissue for Descemet stripping automated endothelial keratoplasty. METHODS: Seventeen corneas were used for this study. Five corneas were cut with the laser at a depth of 420 to 500 µm to produce a tissue thickness of approximately ≤70 µm. Five corneas served as an uncut comparison group. Vital dye staining and computer digitized planimetry analysis were performed on these corneas. The 7 remaining corneas were cut for scanning electron microscopy evaluation. RESULTS: The mean central posterior stromal thickness of cut corneas was 60.6 µm (range, 43-72 µm). Endothelial cell damage in cut and comparison corneas was 3.92% ± 2.22% (range, 1.71%-6.51%) and 4.15% ± 2.64% (range, 1.21%-7.01%), respectively (P = 0.887). Low-magnification (×12) scanning electron microscopy revealed a somewhat irregular-appearing surface with concentric rings peripherally. Qualitative grading of higher magnification (×50) central images resulted in an average score of 2.56 (between smooth and rough). CONCLUSIONS: Ultrathin tissue for Descemet stripping automated endothelial keratoplasty can be safely prepared with minimal endothelial cell damage using a low-pulse energy, high-frequency femtosecond laser; however, the resulting stromal surface quality may not be optimal with this technique.

Descemet's stripping automated endothelial keratoplasty: the tenuous relationship between donor thickness and postoperative vision.

PURPOSE: To determine whether preoperative donor thickness has a relationship with postoperative visual acuity after Descemet's stripping automated endothelial keratoplasty (DSAEK). DESIGN: Retrospective correlation and comparative analysis of an interventional case series. PARTICIPANTS: A total of 418 eyes of 292 patients undergoing DSAEK surgery for Fuchs' endothelial dystrophy without visual loss from comorbidities. METHODS: Descemet's stripping automated endothelial keratoplasty was performed in 548 eyes with Fuchs' dystrophy, and preoperative graft thickness (GT) was recorded. After exclusion of patients with confounding variables that would affect postoperative visual acuity, postoperative best spectacle-corrected visual acuity (BSCVA) was measured at 6 months in 418 eyes. Pearson's correlation analysis was performed between preoperative GT and BSCVA. Cases were split into deciles on the basis of GT and BSCVA and then compared with 1-way analysis of variance (ANOVA) and chi-square test. MAIN OUTCOME MEASURES: Best spectacle-corrected visual acuity at 6 months postoperatively. RESULTS: Mean GT of the series was 162.9±29.0 µm (range, 80-265 µm), and mean Snellen BSCVA was 20/28 with a range of 20/16 to 20/70. There was a weak correlation between GT and BSCVA that was significant (R = 0.236, P<0.001) but only accounted for 5% of the visual outcome (R(2) = 0.056). Visual outcome was best within the thinnest decile group of 45 donors (GT range, 80-124), with a mean Snellen BSCVA of 20/25 (range, 20/20-20/50), and worst within the thickest decile group of 41 donors (GT range, 200-265), with a mean Snellen BSCVA of 20/33 (range, 20/20-20/70). Post hoc comparison of BSCVA between the thickest and thinnest groups was significant (P = 0.006). CONCLUSIONS: Preoperative GT may have a small effect on visual outcome in the extremes of thickness, but not in the common range of 100 to 200 µm. Donor thickness has a tenuous relationship with visual outcome, accounting for only 5% of the variance in vision between patients, and should play a minimal role in surgical planning.

Graft dislocation and hypotony after Descemet's stripping automated endothelial keratoplasty in patients with previous glaucoma surgery.

PURPOSE: To determine if patients with prior glaucoma surgery experience higher rates of postoperative graft dislocation after Descemet's stripping automated endothelial keratoplasty (DSAEK) and to determine if postoperative hypotony may be a risk factor in these patients. DESIGN: Retrospective, comparative analysis of an interventional case series. PARTICIPANTS: Eight hundred fifty-four eyes (67 eyes with prior glaucoma surgery and 787 controls) from 582 patients who underwent DSAEK at 1 institution between January 2005 and April 2011. METHODS: Groups were compared with regard to preoperative, intraoperative, and postoperative parameters. Continuous variables were compared using the independent samples t test or Mann-Whitney U test. Categorical variables were compared using the chi-square test or Fisher exact test. MAIN OUTCOME MEASURES: Frequencies of postoperative graft dislocation and postoperative hypotony. RESULTS: Study eyes before surgery differed from control eyes with regard to corneal thickness (768 vs. 655 µm; P<0.001) and intraocular pressure (13 vs. 16 mmHg; P<0.001). Postoperative graft dislocation occurred significantly more frequently in study eyes compared with control eyes (9% vs. 2%; P = 0.008). Among eyes in which dislocation occurred, postoperative hypotony was present in 5 study eyes (83%) and 0 control eyes. CONCLUSIONS: Previous glaucoma surgery was associated with a significantly increased rate of graft dislocation compared with control eyes. Dislocation was related strongly to postoperative hypotony in eyes with prior glaucoma surgery. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

The safety and efficacy of linezolid and daptomycin as an additive in Optisol-GS against methicillin-resistant Staphylococcus aureus.

PURPOSE: To evaluate the efficacy of adding either linezolid or daptomycin to Optisol-GS donor storage medium in reducing methicillin-resistant Staphylococcus aureus (MRSA) contamination of donor corneas. METHODS: Optisol-GS was supplemented with either linezolid at 2×, 4×, or 10× minimum inhibitory concentration (MIC) or daptomycin and calcium at 5× or 50× MIC. Unsupplemented control groups were also used. Gentamicin-sensitive and gentamicin-resistant isolates of MRSA were added, and vials were refrigerated for 48 hours followed by sampling for viable colony counts immediately upon removal from refrigeration and after warming to room temperature for 3 hours. Safety studies of Optisol-GS supplemented with 50× MIC daptomycin and calcium were performed by evaluating the central corneal thickness and endothelial cell density of the donor cornea. Stability of daptomycin in Optisol-GS at storage was also tested. RESULTS: No added benefit was observed with linezolid supplementation to Optisol-GS against gentamicin-sensitive MRSA, with reduction in viable colony counts by >90% in all groups. No benefit was observed with linezolid supplementation against gentamicin-resistant MRSA, with the majority of inocula remaining viable in all groups. Viable counts of gentamicin-sensitive MRSA and gentamicin-resistant MRSA were effectively reduced with both 5× MIC and 50× MIC daptomycin supplementation. 50× MIC daptomycin-supplemented Optisol-GS had no appreciable effect on the central corneal thickness or endothelial cell density of the donor cornea and was stable at storage for 14 days. CONCLUSIONS: The addition of daptomycin to Optisol-GS significantly increases the anti-MRSA activity of the medium without any apparent negative effects on donor corneal tissue.

Three-year visual acuity outcomes after Descemet's stripping automated endothelial keratoplasty.

PURPOSE: To evaluate the long-term improvement of visual acuity after Descemet's stripping automated endothelial keratoplasty (DSAEK) surgery. DESIGN: Retrospective analysis of a noncomparative, interventional case series. PARTICIPANTS: One hundred eight patients undergoing DSAEK surgery for Fuchs' endothelial dystrophy and pseudophakic bullous keratopathy without other ocular comorbidities who completed a full 3-year follow-up period. METHODS: Postoperative best spectacle-corrected visual acuity (BSCVA) was recorded at 6, 12, 24, and 36 months. Improvement in BSCVA between each time point was evaluated using paired-samples t tests. Subanalysis evaluating the percentage of eyes achieving a BSCVA of 20/20, 20/25, 20/30, and 20/40 at each time point was performed. MAIN OUTCOME MEASURES: Improvement in postoperative BSCVA. RESULTS: There was a statistically significant trend toward improvement in average BSCVA with time at postoperative month 6 and postoperative years 2 and 3. There were also increasing proportions of eyes reaching vision of 20/20, 20/25, and 20/30 from 6 months to 1 year, 1 year to 2 years, and 2 years to 3 years. The percentage of patients achieving 20/25 BSCVA improved from 36.1% at 6 months to 70.4% at 3 years after surgery. A similar increase in the percentage of patients reaching a BSCVA of 20/20 after DSAEK surgery also was observed from 11.1% at 6 months to approximately 47.2% at 3 years. CONCLUSIONS: There is gradual improvement of visual acuity over time after DSAEK surgery for Fuchs' endothelial dystrophy and pseudophakic bullous keratopathy in patients without other vision-limiting ocular comorbidities. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

The endothelial safety of using a gentian violet dry-ink "S" stamp for precut corneal tissue.

PURPOSE: To determine the endothelium damage resulting from the application of "dry" gentian violet (GV) stromal markings on corneas precut for Descemet stripping automated endothelial keratoplasty (DSAEK) using a Moria "S" Stamp. METHODS: Five precut corneas had the stromal graft bed marked with GV using the Moria "S" stamp and 6 precut corneas were left unmarked as controls. After applying the ink to the stamp, care was taken to allow the alcohol carrier to dry for 10 seconds before applying the dry dye to the stromal surface. Tissue was then trephinated and stained with calcein AM to assess endothelial viability. Grafts were photographed and digital pixel planometry, using an established analysis technique, was used to compare the damage between the control and experimental groups. RESULTS: The mean percent cell damage of corneas treated with GV "S" stamp (n = 5) was 8.6% (range 4.4-12.9), and it was 8.1% (range 3.9-15.1) in the DSAEK control set (n = 6). Median percent cell damage was 6.7% among GV-treated corneas and 7.4% among control corneas. The distributions were not significantly different between groups (Mann-Whitney U test = 15.0, two-tailed P = 1.0). Moreover, no "S" pattern of damage was seen in any study eye. CONCLUSIONS: There were no significant differences in endothelial damage between the 2 groups. GV stromal markings may be applied without undue damage to the endothelium using the dry-ink technique described.

Graft rejection after Descemet's stripping automated endothelial keratoplasty: graft survival and endothelial cell loss.

PURPOSE: To evaluate the effects of graft rejection episodes after Descemet's stripping automated endothelial keratoplasty surgery (DSAEK) on long-term endothelial cell density (ECD) decline and graft survival. DESIGN: Retrospective, comparative analysis of an interventional case series. PARTICIPANTS: We included 615 eyes of 415 Fuchs' dystrophy patients at a single institution with ≥ 6 months follow-up and without comorbidities known to influence postoperative ECD. All patients were enrolled as part of an ongoing, institutional review board-approved clinical protocol for a long-term, prospective study of endothelial keratoplasty in patients with endothelial dysfunction. METHODS: Preoperative specular microscopy of donor corneal tissue was performed. Postoperative specular microscopy measurements were recorded at 6 and 12 months, and yearly thereafter. The percentages of endothelial cell loss recorded at 1, 2, 3, and 4 years were compared with the Mann-Whitney U test. MAIN OUTCOME MEASURES: Percentage ECD declines were calculated at each time point from the results of the preoperative and postoperative specular microscopy. Patients with graft rejection episodes and late endothelial failure were identified. Graft rejection was defined as findings of keratic precipitates with or without corneal edema, or anterior chamber cell and flare with or without corneal edema after the initial resolution of perioperative inflammation. RESULTS: We identified 45 cases of graft rejection. The greatest number of rejections occurred between postoperative months 12 and 18. Eyes with a graft rejection episode had a higher median percentage decline in ECD at all time points compared with eyes without graft rejection episodes. This was statistically significant at 2 and 3 years postoperatively. CONCLUSIONS: There is a trend toward a greater percentage of ECD loss with time in eyes experiencing graft rejection after DSAEK surgery. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Endothelial keratoplasty: the relationship between donor tissue size and donor endothelial survival.

PURPOSE: To determine if donor graft diameter has a relationship with postoperative central endothelial cell density (ECD) and survival in Descemet's stripping automated endothelial keratoplasty (DSAEK). DESIGN: Retrospective, comparative analysis of an interventional case series. PARTICIPANTS: Three hundred thirty-one eyes of 243 patients undergoing DSAEK surgery for Fuchs' endothelial dystrophy without a history of rejection or graft dislocation. METHODS: Descemet's stripping automated endothelial keratoplasty was performed in 331 eyes with Fuchs' dystrophy. After exclusion of confounding variables, postoperative ECD and percentage cell loss was compared for 8.0-mm grafts (n = 154) versus 8.5-mm grafts (n = 165) over a 2-year postoperative period. MAIN OUTCOME MEASURES: Total central ECD and percentage of donor endothelial cell loss as measured by specular microscopy of central ECD. RESULTS: Mean preoperative ECD was 2635 cells/mm(2) for 8.0-mm grafts and 2732 cells/mm(2) for 8.5-mm grafts (P = 0.003). Mean ECD (and percent cell loss from before surgery) was 2011 cells/mm(2) (22.9%) for 8.0-mm grafts and 2078 cells/mm(2) (23.5%) for 8.5-mm grafts at 6 months, 2009 cells/mm(2) (23.3%) and 2113 cells/mm(2) (23.1%) at 1 year, and 2060 cells/mm(2) (23.4%) and 2111 cells/mm(2) (24.3%) at 2 years (P>0.72 for percentage cell loss at all time points). CONCLUSIONS: Descemet's stripping automated endothelial keratoplasty grafts with a diameter of 8.5 mm do not offer a clinical advantage over smaller 8.0-mm grafts for postoperative endothelial cell counts in the first 2 years after surgery. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Endothelial keratoplasty: the relationship between donor tissue storage time and donor endothelial survival.

PURPOSE: To evaluate the relationship between storage time in Optisol GS (Bausch & Lomb, St. Louis, MO) and postoperative cell loss after Descemet's stripping automated endothelial keratoplasty (DSAEK) surgery. DESIGN: Retrospective analysis of a noncomparative, interventional case series. PARTICIPANTS: Three hundred sixty-two eyes of 265 patients undergoing DSAEK surgery for Fuchs' endothelial dystrophy. METHODS: Storage times (death to surgery) of donor tissue were recorded for 362 eyes undergoing DSAEK surgery. Donor cell loss at 6, 12, and 24 months was recorded. Analysis of storage times with endothelial cell loss was performed using a Pearson correlation coefficient and an independent samples Student t test. MAIN OUTCOME MEASURES: Percentage of donor endothelial cell loss as measured by specular microscopy of central endothelial cell density (ECD). RESULTS: The mean storage time was 98.95 ± 33 hours (range, 20.65-186.02 hours). The mean percent endothelial cell loss from before to after surgery was 29 ± 16% at 6 months (n = 362), 31 ± 16% at 12 months (n = 263), and 32 ± 20% at 24 months (n = 98). Storage time did not correlate significantly with endothelial cell loss at any postoperative time point (6 months: r = -0.047, P = 0.373; 12 months: r = -0.023, P = 0.709; 24 months: r = -0.14, P = 0.169). The mean cell loss for corneas stored 0 to 4 days (n = 55) was 32 ± 17% at 2 years and the mean cell loss for corneas stored for more than 4 days (n = 43) was 30 ± 18% at 2 years (P = 0.57). At the extremes of storage time, 10 corneas stored for the shortest time (1.5 days) had a 1-year cell loss of 33% and 10 corneas stored for the longest time (7 days) had a 1-year cell loss of 30% (P = 0.45). CONCLUSIONS: No correlation was found between the characteristic of storage time and the decline of ECD. Surgeons should not make special requests to the eye bank for short storage times with the hope of improving donor endothelial survival. The upper limit of donor storage time as it relates to acceptable postoperative endothelial cell loss is not known.

Descemet stripping automated endothelial keratoplasty in eyes with previous trabeculectomy and tube shunt procedures: intraoperative and early postoperative complications.

PURPOSE: To evaluate the intraoperative and early postoperative outcomes of Descemet stripping automated endothelial keratoplasty (DSAEK) in patients with previous glaucoma filtering surgeries. METHODS: A retrospective review of all DSAEK surgeries performed at one center comparing complications of DSAEK in eyes with previous glaucoma filtering procedures (study eyes) with a time-matched group of all other DSAEK cases (control eyes). RESULTS: There were 28 study eyes, 19 with previous trabeculectomies and 9 with previous glaucoma drainage devices (GDDs) and 431 control eyes. Study group intraoperative complications included 1 compromised bleb and 1 loss of donor tissue because of traumatic manipulation. One intraoperative complication, a perforation of the donor tissue, occurred in the control group. Venting stab incisions were used more often in study eyes (n = 5; 18%) than in control eyes (n = 12; 4.4%) (P = 0.002). GDD tubes were trimmed in 2 eyes (22%). No intraoperative manipulations were used to occlude the glaucoma filters or tubes. Postoperative complications in the study group included 1 dislocation (3.6%) and 1 decentered graft (3.6%) and 1 eye with loss of pressure control (3.6%), whereas in the control group, there were 10 dislocations (2.3%) and 1 decentered graft (0.2%) (P = 0.267 for dislocations and P = 0.118 for decentered grafts). One episode of pupillary block (0.2%) occurred in the control group, and none occurred in the study group. No primary graft failures occurred in either group. CONCLUSIONS: DSAEK surgeries in eyes with previous glaucoma filtering procedures were performed without primary graft failure and with reasonably low dislocation (3.6%) and graft decentration (3.6%) rates. Although the intraoperative complication rate for the study group (7.1%) was higher than the rate for the control group (0.23%), excellent early postoperative outcomes can be achieved when DSAEK is performed in eyes with previous trabeculectomies and GDDs.

Complications and clinical outcomes of descemet stripping automated endothelial keratoplasty with intraocular lens exchange.

PURPOSE: To evaluate complications and clinical outcomes of Descemet stripping automated endothelial keratoplasty (DSAEK) with intraocular lens (IOL) exchange compared with DSAEK alone. DESIGN: Retrospective, interventional case series. METHODS: DSAEK was performed in 19 eyes in which the anterior chamber IOL was exchanged for a posterior chamber IOL (study group) and in 188 eyes in which the posterior chamber IOL was left in place (comparison group). The complications of graft dislocations, primary graft failure episodes, and pupillary block were recorded for all eyes. Six-month best spectacle-corrected visual acuity and mean central endothelial cell density were measured prospectively and then compared with preoperative values for all eyes. RESULTS: Dislocations occurred in 0 (0%) of 19 eyes in the study group and in 5 (3%) of 188 eyes in the comparison group (P = .47), with 0 primary graft failures and 0 pupillary block episodes in either group. Preoperative mean best spectacle-corrected visual acuity for those eyes without any underlying ocular comorbidities was 20/205 and 20/100 in the study and comparison groups, respectively (P = .18). Mean best spectacle-corrected visual acuity at 6 months improved to 20/48 in the study group and to 20/34 in the comparison group, a statistically significant difference (P = .01). Mean donor cell loss at 6 months was 33% in the study group and 26% in the comparison group (P = .18). CONCLUSIONS: Concurrent IOL exchange with DSAEK surgery does not increase the dislocation, primary graft failure, or pupillary block rates in the immediate postoperative period. Donor endothelial cell loss in DSAEK was not increased significantly by IOL exchange. Visual acuity was slightly worse after combined surgery than after DSAEK alone.

Analysis of posterior donor corneal parameters 1 year after Descemet stripping automated endothelial keratoplasty (DSAEK) triple procedure.

BACKGROUND: Although Descemet stripping automated endothelial keratoplasty (DSAEK) was demonstrated to be effective for the treatment of endothelial corneal diseases, a variable hyperopic shift has been measured as a common occurrence postoperatively. The aim of this work was to investigate the variance in the corneal and refractive responses to DSAEK combined with phacoemulsification and implantation of intra-ocular lens (IOL), namely the DSAEK triple procedure. METHODS: The refractive, topographic, and anterior segment optical coherence tomography (AS-OCT) data of 23 eyes treated with DSAEK triple procedure were analyzed. A mean refractive IOL target of -1.04 +/- 0.09 D was calculated based on empirical data of our early experience to achieve emmetropia in all the eyes included in the study. Donor corneal parameters, i.e., graft diameter, thickness, and profile, were investigated in order to verify their possible role in the variable refractive shift after DSAEK. RESULTS: Although the 1-year mean refractive outcome was close to emmetropia (-0.01 +/- 0.89 D), the average difference between the targeted postoperative refraction and the 1-year postoperative spherical equivalent refraction was +0.98 +/- 0.87 D. Correlations of refractive change with central graft thickness (r = 0.36, p = 0.05) and graft diameter (r = 0.45; p = 0.03) were statistically significant. AS-OCT analysis revealed how the graft shape, with graft thicker in the periphery compared with the center, contributed to reduce the radius of curvature of the posterior cornea, thus favoring the hyperopic shift postoperatively. CONCLUSIONS: DSAEK triple procedure provides negligible changes in the surface topography, however with a variable amount of hyperopic shift postoperatively. Central graft thickness and graft profile together contributed to approximately two-thirds of the variance in refractive shift postoperatively. Lenticule diameter provided a minor influence on postoperative hyperopic shift than other graft parameters.