Changes in Corneal Curvatures and Anterior Segment Parameters after Descemet Stripping Automated Endothelial Keratoplasty

Hitting the refractive target in corneal endothelial transplantation triple procedures: A systematic review

In phakic patients Descemet stripping automated endothelial keratoplasty (DSAEK) or Descemet membrane endothelial keratoplasty (DMEK) are frequently combined with phacoemulsification and intraocular lens (IOL) implantation (triple procedure). This surgery might cause a refractive shift difficult to predict. Early DMEK and DSAEK results have shown a tendency toward a hyperopic shift. Myopic postoperative refraction is typically intended to correct this postoperative refractive defect and to bring all eyes as close to emmetropia as possible. We sought to understand the mechanism underlying the hyperopization and to identify predictive factors for poorer refractive outcomes, the most suitable target refraction and IOL calculation methods in patients undergoing combined cataract extraction and lamellar endothelial corneal transplantation (DSAEK or DMEK) for endothelial dysfunctions. Of the 407 articles analyzed, only 18 were included in the analysis. A myopic target between -0.50 D and -0.75 was the most common (up to -1.50 for DSAEK triple procedures), even though no optimum target was found. Hyperopic surprises appeared more frequently in corneas that were flatter in the center than in the periphery (oblate posterior profile). Among the numerous IOL calculation formulas, there was no apparent preference.

Systematic Review and Meta-analysis: Outcomes After Descemet Membrane Endothelial Keratoplasty Versus Ultrathin Descemet Stripping Automated Endothelial Keratoplasty

PURPOSE

To compare the efficacy and safety of ultrathin Descemet stripping (automated) endothelial keratoplasty (UT-DS(A)EK) versus Descemet membrane endothelial keratoplasty (DMEK) for the treatment of Fuchs endothelial dystrophy (FED) and bullous keratopathy (BK).

DESIGN

Systematic review and meta-analysis.

METHODS

Literature containing DMEK and UT-DSAEK were searched in the Cochrane Database of Systematic Reviews, PubMed, EMBASE, LILACS, and through manual reference searching. Studies were included that measured the outcome of interventions-including best corrected visual acuity (BCVA), endothelial cell density (ECD), and postoperative complications, especially graft detachment with the need of re-bubbling, graft rejection, graft failure, and postoperative elevated intraocular pressure (IOP)-in patients with FED and BK. Included outcomes were pooled as standardized mean differences (SMD) or risk ratios (RR) using random effects models. Inter-study heterogeneity was assessed using the Q-test and I2 statistic.

RESULTS

Seven (of 163) studies met all the inclusion and exclusion criteria. Meta-analysis showed a significantly better BCVA 12 months postoperatively, but an increased re-bubbling rate in eyes after DMEK compared with eyes after UT-DS(A)EK (BCVA: SMD = 0.50 [95% CI 0.27-0.74] and re-bubbling rate: RR = 0.33 [95% CI 0.16-0.67]). All other parameters did not differ significantly between both interventions, although estimates were imprecise (graft failure: RR = 0.65 [95% CI 0.18-2.30], graft rejection: RR = 1.40 [95% CI 0.27-7.30], and postoperative intraocular pressure elevation: RR = 1.14 [95% CI 0.60-2.18]). Postoperative SMDs of ECD could not be evaluated due to significant heterogeneity between studies.

CONCLUSIONS

Although the improvement in BCVA was higher after UT-DS(A)EK than after conventional DS(A)EK, the BCVA after DMEK was still superior. The complication rates were comparable for both procedures, except for the higher rate of re-bubbling after DMEK.

Anterior Chamber Characteristics, Endothelial Parameters, and Corneal Densitometry After Descemet Stripping Automated Endothelial Keratoplasty in Patients With Fuchs Dystrophy

Purpose

To compare anterior segment parameters in patients with Fuchs endothelial dystrophy (FED) who underwent Descemet stripping automated endothelial keratoplasty (DSAEK) in one eye and no corneal surgery in the fellow eye.

Methods

This prospective study was conducted on 28 eyes of 14 patients with FED who underwent DSAEK in one eye at least one year prior (DSAEK group) and no corneal surgery in the fellow eye (control group). Each eye was analyzed with the anterior segment optical coherence tomography, specular microscopy, and Scheimpflug imaging systems. Data were compared between the two groups.

Results

The mean age of the patients was 76.9 ± 7.0 years. There were no statistically significant differences in the mean central corneal thickness (CCT), central anterior chamber depth, anterior chamber angle parameters, cylinder and keratometry values between two groups (all P-values > 0.05). The paracentral corneal thickness, corneal volume, endothelial cell density, and hexagonal cell ratio measurements were statistically significantly higher in the DSAEK group than the control (all P-values < 0.05), and anterior chamber volume in the DSAEK group was significantly less than the control (P = 0.046). While posterior and total corneal densitometry values in the DSAEK group were statistically significantly lower than the control (P < 0.001 and P = 0.011, respectively), there were no statistically significant differences in the anterior or middle corneal densities (P = 0.108 and P = 0.134, respectively).

Conclusion

We found that total corneal densitometry value decreased in DSAEK group. Although DSAEK surgery did not affect the anterior chamber angle parameters, it reduced the anterior chamber volume and increased the corneal volume and paracentral corneal thickness due to the addition of the DSAEK graft.

Refractive outcomes following cataract combined with lamellar keratoplasty: femtosecond-DSEK versus microkeratome-DSAEK

PURPOSE

Prediction of postoperative refraction following posterior lamellar keratoplasty is crucial for choosing proper intraocular lens power in combined surgeries. Femtosecond laser-assisted Descemet stripping endothelial keratoplasty (FS-DSEK) creates thin, planar grafts while microkeratome-assisted Descemet's stripping automated endothelial keratoplasty (DSAEK) creates non-planar, concaved grafts. We evaluated whether this fundamental difference affects the refractive outcomes in cataract surgery combined with FS-DSEK compared to cataract surgery combined with microkeratome-assisted DSAEK.

METHODS

A retrospective analysis of 28 patients who underwent FS-DSEK combined with phacoemulsification and intraocular lens (IOL) implantation (group A) compared to 26 patients who underwent microkeratome-assisted DSAEK combined with phacoemulsification and IOL implantation (group B). Pre- and 1-year postoperative best-corrected visual acuity (BCVA), keratometry values, corneal thickness, central-to-peripheral graft thickness ratio (C/P ratio), and target postoperative spherical equivalent (SE) versus actual postoperative SE were analyzed.

RESULTS

Target postoperative SE and actual postoperative SE significantly shifted toward hyperopia in group B, but not in group A. Postoperative hyperopic shifts were 0.14 D and 1.13 D in groups A and B, respectively (P < 0.001). BCVA improved after surgery in both groups, with no significant difference between the groups. Postoperative C/P ratio differed significantly between the groups and was negatively correlated with postoperative hyperopic shift (r =  - 0.616, P < 0.001).

CONCLUSION

Refractive outcomes of cataract surgery combined with FS-DSEK are relatively neutral, whereas those of cataract surgery combined with microkeratome-assisted DSAEK cause significant hyperopic shift. Clinicians should select accordingly an appropriate intraocular lens power when performing these surgeries.

[Refractive changes after different modifications of endothelial keratoplasty]

PURPOSE

To evaluate changes in clinical refraction after Descemet Stripping Automated Endothelial Keratoplasty (DSAEK) and Descemet Membrane Endothelial Keratoplasty (DMEK), and assess their correlation to the thickness of the transplant.

MATERIAL AND METHODS

The main study group included 40 patients (40 eyes) after DSAEK and 20 patients (20 eyes) after DMEK, the control group consisted of 20 patients (20 eyes) without any corneal pathologies or history of surgical treatment. In addition to standard examination, patients of the main group had central corneal thickness and transplant thickness regularly measured; they were also monitored by optical coherence tomography (Optovue, U.S.A.), computed tomography and aberrometry of the cornea performed on Pentacam device. The control group had the same examination regimen.

RESULTS

Best corrected visual acuity after 6 months was on average 0.2 higher in DMEK patients compared to those who underwent DSAEK; after one year - 0.1 higher. Clinical refraction data shows presence of hypermetropic changes after DSAEK surgery. Induced astigmatism after one year was 0.4 Diopters in DSAEK patients, but did not exceed 0.1 Diopters in DMEK patients. Stabilization of the corneal thickness in DMEK group occurred on the 3-4^th month, in DSAEK group - 6-7^th month. Certain values of higher-order aberrations (3-6) and root-mean-square deviation (RMS) of the wave-front of anterior corneal surface in DSAEK and DMEK groups were higher than in the control group. Aberrations on the posterior corneal surface in DMEK group were significantly lower than in DSAEK group. There were no statistically significant differences in 'final' RMS higher-order aberrations between DMEK and DSAEK groups.

Precut Post-Laser In Situ Keratomileusis / Photorefractive Keratectomy Donor Corneas for Use in Endothelial Keratoplasty: Potential Impact of Postcut Morphology on Visual Outcomes

PURPOSE

To evaluate the accuracy, complication rates, cut quality, and degree of induced hyperopic shift of eye bank-prepared post-laser in situ keratomileusis (LASIK)/photorefractive keratectomy (PRK) donor corneas compared to those of non-post-LASIK/PRK donor corneas.

METHODS

The cut accuracy and failure rates of all post-LASIK/PRK donor cornea tissue processed for use in Descemet stripping automated endothelial keratoplasty (DSAEK) from January 2012 through December 2016 were compared to control cornea donor tissue. Corneas were analyzed for regularity and morphology of cut using anterior segment optical coherence tomography images. Using a mathematical model, the hyperopic shifts induced by post-LASIK/PRK donor lenticules were compared to the control corneas.

RESULTS

During the study period, 733 post-LASIK/PRK and 10 437 non-post-LASIK/PRK donor corneas were processed for DSAEK. Cut accuracy and quality were similar (P > .05), but there was an increased tissue wastage rate of 5.0% compared to 2.2% (P < .000001). For tissue < 100 μm in central thickness (P = .0001), and for tissue between 100 and 150 μm in central thickness (P = .0023), the difference between central and peripheral thickness when comparing the post-LASIK/PRK and control corneas was statistically significant. These differences resulted in a 1.96 diopter (D), 1.60 D, and 2.35 D hyperopic shift when using donor corneas 100 μm, 125 μm, and 150 μm thick, respectively, from post-LASIK/PRK donors compared to 1.11 D, 0.38 D, and 1.96 D from control donors.

CONCLUSIONS

Eye bank technicians and surgeons should be aware of the increased risk of tissue wastage when cutting post-LASIK/PRK corneas compared to non-post-LASIK/PRK donors. Surgeons should also be aware of the theoretical increase in hyperopic shift when using post-LASIK/PRK donor corneas compared to non-post-LASIK/PRK donors when cut to less than 150 μm. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Systematic Review and Meta-Analysis of Clinical Outcomes of Descemet Membrane Endothelial Keratoplasty Versus Descemet Stripping Endothelial Keratoplasty/Descemet Stripping Automated Endothelial Keratoplasty

PURPOSE

To review and compare the published reports of Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping endothelial keratoplasty/Descemet stripping automated endothelial keratoplasty (DSEK/DSAEK) procedures with regard to endothelial cell density/loss, best spectacle-corrected visual acuity, central corneal thickness, subjective outcomes (patient's reported satisfaction/preference), and postoperative complications.

METHODS

A thorough search was conducted in the databases including AMED, EMBASE, Cochrane Database of Systematic Reviews, and MEDLINE without date restrictions. Systematic reviews, meta-analysis, randomized controlled trials, case series, and audits comparing DMEK and DSAEK were included.

RESULTS

DMEK is superior to DSAEK for the following outcomes: visual acuity, central corneal thickness, and patient satisfaction. There was a statistically significant difference in the mean spectacle-corrected visual acuity at 6 months for DMEK (mean = 0.161, SD = 0.129) and DSAEK eye (mean = 0.293, SD = 0.153) conditions; t (297) = 8.042, P < 0.0001. The pooled mean difference was -0.13 (95% confidence interval, -0.16 to -0.09) and I = 44%, indicating better visual acuity for DMEK. Mean postoperative endothelial cell density showed statistically no significant difference in the mean values for DMEK (mean = 1855, SD = 442) and DSAEK eye (mean = 1872, SD = 429) conditions; t (336) = 0.375, P = 0.708. A higher proportion of patients prefer DMEK to DSAEK. However, DSAEK is superior to DMEK with respect to the need for rebubbling as the rebubbling rate was higher in the DMEK group.

CONCLUSIONS

Although DMEK is associated with a higher rate of rebubbling, better visual outcomes were seen in DMEK.

Descemet's Stripping Automated Endothelial Keratoplasty versus Descemet's Membrane Endothelial Keratoplasty in the Fellow Eye for Fuchs Endothelial Dystrophy: A Retrospective Study

Aim. To evaluate visual outcome and endothelial cell density (ECD) after Descemet's Membrane Endothelial Keratoplasty (DMEK) in comparison with Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK) in the fellow eye for Fuchs endothelial dystrophy (FED). Design. Single-centre, retrospective case series. Methods. 30 eyes of 30 patients undergoing DMEK, who completed a 1-year follow-up, were compared with 30 fellow eyes which underwent DSAEK for bilateral FED. Main outcome measures studied included Best Corrected Visual Acuity (BCVA) and ECD during a 1-year follow-up period. Results. BCVA improved from 0.78 ± 0.35 logMAR, and 0.73 ± 0.31 logMAR before surgery to 0.22 ± 0.1 logMAR and 0.35 ± 0.12 logMAR 6 months after DMEK and DSEK, respectively (P < 0.001). At one year after surgery, the BCVA was maintained at 0.21 ± 0.12 logMAR and 0.34 ± 0.1 logMAR, respectively, after DMEK and DSAEK. A statistically better visual outcome was observed after DMEK compared to DSAEK (P < 0.05) in fellow eyes. Conclusions. DMEK provided better visual rehabilitation when compared to DSAEK. Nevertheless, there were no significant differences with regard to the ECD within a 1-year follow-up.

The First 100 Eyes of Standardized Descemet Stripping Automated Endothelial Keratoplasty versus Standardized Descemet Membrane Endothelial Keratoplasty

PURPOSE

To compare results of the first 100 eyes of Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK) that were performed with a standardized technique at a single institution.

DESIGN

Single-center, retrospective case series.

PARTICIPANTS

The first 100 eyes of standardized DSAEK and DMEK that underwent surgery for Fuchs corneal dystrophy at our center. We excluded patients with prior ocular surgery other than cataract surgery to limit confounding variables.

METHODS

Best spectacle-corrected visual acuity (BSCVA; in logarithm of the minimal angle of resolution [logMAR] units) was obtained and specular microscopy of donor corneal tissue was performed before surgery. Postoperative complications, BSCVA, and the percent of endothelial cell loss (ECL) recorded at 6 months were compared with the Student t test. Patients with pre-existing ocular comorbidity that impacted visual potential such as macular degeneration, amblyopia, advanced glaucoma, and other optic neuropathies were excluded from the analysis of visual acuity, but were included for the outcomes of complications and ECL.

MAIN OUTCOME MEASURES

Visual acuity improvement, ECL 6 months after surgery, postoperative complications, iatrogenic primary graft failure (IPGF), and rebubbling.

RESULTS

Of the 200 eyes, 62 DSAEK eyes and 70 DMEK eyes had 6-month BSCVA available and no vision-limiting comorbidities. Mean BSCVA increased from 0.41±0.19 logMAR and 0.27±0.11 logMAR before surgery to 0.20±0.13 logMAR and 0.11±0.13 logMAR 6 months after DSAEK and DMEK, respectively (P<0.001). Seventy-one DSAEK eyes and 70 DMEK eyes had 6-month ECL data available: ECL was 25.9±14.0% after DSAEK and 27.9±16.0% after DMEK (P=0.38). There were no IPGFs in the DSAEK cohort and there were 4 of 100 IPGFs after DMEK (P=0.12). Rebubbling was performed in 2 of 100 eyes after DSAEK and in 6 of 100 eyes after DMEK (P=0.28).

CONCLUSIONS

Compared with DSAEK, DMEK provided better visual recovery and comparable 6-month ECL. The DMEK group had a higher, although not statistically significant, percentage of rebubbling procedures and IPGFs.

Refractive outcomes of Descemet membrane endothelial keratoplasty triple procedures (combined with cataract surgery)

PURPOSE

To describe the refractive outcomes of triple Descemet membrane endothelial keratoplasty (DMEK).

DESIGN

Retrospective case series.

METHODS

The study included patients with Fuchs endothelial dystrophy and cataract without coincident pathology.

RESULTS

Outcomes of 108 sequential triple DMEK procedures were evaluated. With a mean follow-up of 11.9 months, the median corrected distance visual acuity (CDVA) was 20/20 (range 20/15 to 20/40) and the median uncorrected distance visual acuity in eyes with a distance target (n = 84) was 20/40 (range 20/20 to 20/200). Forty-five percent of patients gained 3 or more lines of CDVA. The median refractive error was +0.43 diopter (D) (interquartile range, -0.34 to +1.17 D). Aspheric intraocular lenses (IOLs) (n = 91) did not significantly change refractive astigmatism (mean: preoperative +0.926 D ± 0.144 [SD]; postoperative +0.945 ± 0.129 D) (P = .83), while toric IOLs (n = 9) did (mean: preoperative +2.47 ± 0.36 D; postoperative +0.94 ± 0.90 D) (P = .0015). The anterior curvature measured by Scheimpflug imaging (Pentacam) did not significantly change (mean -0.06 ± 0.47) (P = .41); however, keratometry by partial coherence interferometry (IOLMaster) did (mean -0.6 ± 0.9 D) (P < .0001).

CONCLUSIONS

Triple DMEK safely achieved excellent CDVA. Selection of the optimum IOL power is complicated by several factors. Because Fuchs dystrophy induces changes predominately in the central cornea, measurements averaging curvature over a larger area might underreport significant refractive deviations. In the absence of an algorithm to more precisely individualize IOL calculations, a refractive target of -0.75 to -1.00 D will help reduce the proportion of eyes left hyperopic.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Retrospective contralateral study comparing Descemet membrane endothelial keratoplasty with Descemet stripping automated endothelial keratoplasty

PURPOSE

In this retrospective study, the visual outcomes and postoperative complications after Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK) in the fellow eye were compared. The patient's satisfaction was evaluated.

METHODS

A retrospective analysis of 10 patients, who underwent DSAEK in one eye and DMEK surgery in their fellow eye, was performed. Intraoperative and postoperative complications were recorded. Visual and refractive outcomes were evaluated, including higher-order aberrations (HOA) and contrast thresholds. A subjective questionnaire was used to evaluate patient satisfaction.

RESULTS

Best-corrected visual acuity (BCVA) was significantly better in DMEK when compared with DSAEK (0.16±0.10 vs 0.45±0.58 logMAR, P=0.043). Contrast threshold was significantly higher after DMEK than after DSAEK (0.49±0.23 vs 0.25±0.18, P=0.043). Post-keratoplasty astigmatism, mean spherical equivalent, and HOA did not differ. Nine out of ten patients preferred the DMEK procedure. Visual outcome (4.80±1.14 vs 4.50±1.58, P=0.257), surgery associated pain and burden (DMEK: 1.30±0.48 vs DSAEK: 1.30±0.48, P=1.0), estimated time for recovery and rehabilitation (27.6±54.0 vs 24.9±54.8 days, P=0.173), and mean patient satisfaction (5.40±0.84 vs 5.00±1.05, P=0.257) were evaluated equally.

CONCLUSION

Patient satisfaction reached high, equal values after DMEK and after DSAEK. Nevertheless, patients preferred DMEK, if given a choice. Reasons for the preference may include better uncorrected and BCVA, and especially a better contrast sensitivity.

In vitro pilot analysis of uniformity, circularity, and concentricity of DSAEK donor endothelial grafts prepared by a microkeratome

PURPOSE

The aim of this study was to analyze Descemet stripping automated endothelial keratoplasty donor endothelial grafts, prepared by using a microkeratome, in terms of uniformity, circularity, and concentricity.

METHODS

In this pilot study, 12 human donor corneas were prepared by means of a microkeratome and imaged using the Visante anterior segment optical coherence tomography along 4 meridians. The microkeratome enters and exits the corneal tissue at an angle, creating a donor graft bed with a uniform stromal (US) thickness in between the angled edges. We termed the angled portion the "nonuniform stromal transitional annulus" (STA), the point of entry and exit of the microkeratome the "epithelium-to-epithelium" (E-E) diameter, and the length of the US bed the "US" diameter. The E-E and US diameters were measured to create a model of each donor graft, from which circularity and concentricity were calculated. The STA length and height were measured, and the slope was calculated.

RESULTS

The mean E-E diameter was 10.69 ± 0.32 mm (range, 9.46-11.75 mm) and the mean US diameter was 8.96 ± 0.40 mm (range, 7.62-10.28 mm). The microkeratome generated elliptical rather than circular cuts, with a mean eccentricity of 0.34 ± 0.098 (range, 0.22-0.58). Eccentricity values between 0 and 1 represent ellipses, with zero characterizing a circle. The US ellipses and E-E ellipses were not concentric, with a mean deviation of the centers of the shapes of 177.06 ± 92.06 μm (range, 21.95-322.22 μm). The mean STA length was 0.73 ± 0.31 mm (range, 0.25-1.89 mm), the mean height was 0.43 ± 0.08 mm (range, 0.28-0.64 mm), and the mean slope was 34.11 ± 14.00° (range, 8.43-53.67°).

CONCLUSIONS

Microkeratome cuts created nonuniform, noncircular nonconcentric donor grafts. Asymmetry and nonuniformity of donor tissue may help explain suboptimal visual outcomes.

Optimization of intraocular lens constant improves refractive outcomes in combined endothelial keratoplasty and cataract surgery

PURPOSE

To evaluate the accuracy of intraocular lens (IOL) power calculations with A-constant optimization in Descemet's stripping automated endothelial keratoplasty (DSAEK) combined with cataract extraction and intraocular lens implantation (DSAEK triple procedure).

DESIGN

Retrospective case series.

PARTICIPANTS

Thirty eyes of 22 patients with Fuchs' endothelial dystrophy who underwent the DSAEK triple procedure performed by a single surgeon.

METHODS

Prediction errors were calculated retrospectively for consecutive DSAEK triple procedures. These prediction errors then were used to determine an IOL constant for this cohort of patients. The new optimized IOL constant subsequently was compared with the manufacturer's IOL constant, allowing evaluation and quantification of refractive benefits of optimization.

MAIN OUTCOMES MEASURES

The error in diopters (D) of the predicted refraction with the manufacturer's and optimized IOL constants.

RESULTS

Optimization of the A constant decreased the mean absolute error (MAE) from 1.09 ± 0.63 D (range, 0.12-2.41 D) to 0.61 ± 0.4 D (range, 0-1.58 D; P = 0.004). Comparing the intended and final postoperative refractions calculated with the original manufacturer's constant and the optimized constant, 20% versus 43% of all eyes were in the less than 0.5-D range and 50% versus 83% of all eyes were in the less than 1.0-D range of the target refraction. Furthermore, optimization decreased the number of eyes that were more than 1.0 D from the target refraction from 50% to 17%.

CONCLUSIONS

Optimization of the IOL constant showed significantly improved accuracy of predicted postoperative refraction compared with the manufacturer's IOL constant, which may help improve the postoperative refractive outcomes in patients undergoing the DSAEK triple procedure.

Descemet membrane endothelial keratoplasty combined with phacoemulsification and intraocular lens implantation: advanced triple procedure

PURPOSE

To evaluate the functional and morphologic outcome of Descemet membrane endothelial keratoplasty (DMEK) combined with phacoemulsification and intraocular lens implantation in patients suffering from endothelial dysfunction and cataract.

DESIGN

Retrospective, single-center, consecutive case series.

METHODS

Triple-DMEK (DMEK with simultaneous cataract surgery) was performed in 61 consecutive eyes of 56 patients using corneal donor tissue pre-stored in either short-term culture (Optisol-GS) at 4 C or organ culture (Dulbecco's modified Eagle's medium, CorneaMax medium) at 34 C. Main outcome measures included the number of air injections necessary for graft attachment as well as best-corrected visual acuity (BCVA [logMAR]), central corneal thickness (CCT), endothelial cell density (ECD), refractive spherical equivalent, refractive cylinder, and topographic cylinder at 1, 3, and 6 months postoperatively.

RESULTS

BCVA increased from 0.6 ± 0.23 logMAR preoperatively (n = 54) to 0.19 ± 0.22 logMAR at 6 months (n = 27) after surgery (P ≤ .05). ECD of donor corneas decreased from 2573 ± 235 cells/mm(2) (n = 61) to 1550 ± 326 cells/mm(2) (n = 29) after 6 months (P ≤ .05). CCT decreased from 651 ± 69 μm (n = 54) preoperatively to 521 ± 65 μm (n = 27) after 6 months (P ≤ .05). Refractive spherical equivalent was -0.3 ± 2.8 D (n = 27) preoperatively and 0.9 ± 1.5 D 6 months (n = 27) after surgery. A total of 54.5% of eyes were within 1 D of emmetropia (n = 12) and 77.3% were within 2 D of emmetropia (n = 17) 6 months (n = 22) after surgery. Refractive cylinder was -0.9 ± 1.0 D preoperatively (n = 49) and -1.5 ± 1.0 D 6 months (n = 23) after surgery. The change in refractive cylinder within the first month was statistically significant (P ≤ .05; Wilcoxon test). Topographic cylinder was 2.1 ± 1.7 D preoperatively (n = 58) and 1.7 ± 1.1 D 6 months (n = 28) after surgery. Between 3 and 6 months a significant change in topographic cylinder towards lower values was measured (P ≤ 0.05; Wilcoxon test). Optimized spherical results were achieved by selecting intraocular lenses based on a hyperopic shift of -0.75 D.

CONCLUSION

DMEK combined with cataract surgery (triple procedure) can routinely be performed in cases of endothelial dystrophy and cataract. The addition of cataract surgery to DMEK had no adverse effect on endothelial function or graft adhesion and did not increase the likelihood of postoperative complications.

Descemet membrane endothelial keratoplasty versus descemet stripping automated endothelial keratoplasty

PURPOSE

To evaluate visual outcome and endothelial cell survival after Descemet membrane endothelial keratoplasty (DMEK) in comparison with Descemet stripping automated endothelial keratoplasty (DSAEK).

DESIGN

Single-center, retrospective, consecutive case series.

METHODS

Thirty-eight eyes of 38 consecutive patients undergoing DMEK, who completed a 6-month follow-up, were compared with 35 eyes of 35 consecutive patients undergoing DSAEK for Fuchs endothelial dystrophy or pseudophakic bullous keratopathy. Main outcome measures included best-corrected visual acuity (in logarithm of the minimal angle of resolution [logMAR] units) and endothelial cell density within a 6-month follow-up.

RESULTS

Best-corrected visual acuity increased from 0.70 ± 0.48 logMAR and 0.75 ± 0.32 logMAR before surgery to 0.21 ± 0.14 logMAR and 0.48 ± 0.19 logMAR 3 months after DMEK and DSAEK (P < .001), respectively, and to 0.17 ± 0.12 logMAR and 0.36 ± 0.15 logMAR 6 months after DMEK and DSAEK (P < .001), respectively. Endothelial cell density decreased from 2575 ± 260 cells/mm(2) and 2502 ± 220 cells/mm(2) before surgery to 1498 ± 244 cells/mm(2) and 1778 ± 420 cells/mm(2) 3 months after DMEK and DSAEK (P < .001), respectively, and to 1520 ± 299 cells/mm(2) and 1532 ± 495 cells/mm(2) 6 months after DMEK and DSAEK (P = .483), respectively. Central corneal thickness decreased from 652 ± 92 μm before surgery to 517 ± 45 μm 6 months after DMEK, and from 698 ± 137 μm before surgery to 618 ± 66 μm 6 months after DSAEK.

CONCLUSIONS

DMEK provided faster and more complete visual rehabilitation when compared with DSAEK. However, there were no significant differences concerning endothelial cell survival within a 6-month follow-up.

Graft profile and thickness as a function of cut transition speed in Descemet-stripping automated endothelial keratoplasty

PURPOSE

To determine the profile of endothelial keratoplasty lenticules prepared using a microkeratome and evaluate the impact of varying cut transition speed on cut depth and profile using anterior segment optical coherence tomography (AS-OCT).

SETTING

Department of Cornea and External Diseases, Moorfields Eye Hospital, London. United Kingdom.

DESIGN

Experimental study.

METHODS

Fourier-domain AS-OCT was used to image 25 corneal specimens before and after microkeratome dissection with a 350 μm head. A pilot series of 7 corneas were cut and imaged with the following 18 corneas divided into regular cut transition speed and slow cut transition speed groups (9 in each). Proximal, central, and distal precut corneal thickness and post-cut residual bed thickness were measured using the integrated caliper tools of the Fourier-domain AS-OCT device. Cut depth was calculated by subtraction.

RESULTS

The slower microkeratome pass speed produced significantly thinner donor lenticules (mean 148 ± 45 μm [SD]) than the standard pass speed (mean 234 ± 35 μm) (P ≤.0001). In both groups, significant asymmetry was observed in donor lenticules with a deeper cut depth and a thinner lenticule at the beginning of the microkeratome pass (proximal stromal bed). The mean difference between the proximal and distal stromal bed thickness was 61 ± 63 μm in the standard group and 52 ± 22 μm in the slow-pass group (P=.159).

CONCLUSIONS

Reducing the transition speed in microkeratome dissection produced thinner donor lenticules. Thickness asymmetry is an inherent flaw with current microkeratome dissection that cannot be easily corrected by altering preparation technique.

Refractive surgery after Descemet's stripping endothelial keratoplasty

PURPOSE OF REVIEW

Descemet's stripping endothelial keratoplasty (DSEK) has become a preferred surgical correction for endothelial dysfunction. Patient dissatisfaction secondary to refractive error is emerging as a significant complaint after anatomically successful DSEK. This article reviews refractive surgeries after DSEK to address this problem.

RECENT FINDINGS

There are various surgical options available to treat refractive compromise following DSEK. Cataract extraction with intraocular lens (IOL) implantation is a well tolerated option to restore visual acuity after DSEK in cases with significant lens opacities. Laser in-situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) can otherwise successfully correct simple refractive errors. Phototherapeutic keratectomy (PTK) may be employed in cases wherein visually significant subepithelial fibrosis and scarring become evident after DSEK.

SUMMARY

To obtain maximum visual rehabilitation, patients undergoing DSEK may require further refractive surgeries. Cataract extraction, LASIK, PRK, PTK, and various combination procedures have been shown to optimize corneal clarity and visual acuity in patients who previously had successful DSEK with subsequent refractive errors. Technological advancements and continued research are necessary to perfect optimal timing and outcomes of these secondary refractive surgeries.