Preoperative Graft Thickness Measurements Do Not Influence Final BSCVA or Speed of Vision Recovery After Descemet Stripping Automated Endothelial Keratoplasty

Thinning rate over 24 months in ultrathin DSAEK

AIM

To describe the changes in corneal graft thickness following ultrathin Descemet's Stripping Automated Endothelial Keratoplasty (UT-DSAEK) comparing pre- and postoperative values over a 24-month period.

METHODS

In this retrospective single-center case series, patients who received eye bank-prepared tissues for UT-DSAEK surgery were included. Preoperative and postoperative graft thickness measurements were determined in the eye bank and in clinic using anterior segment optical coherence tomography (AS-OCT) images. Graft thickness measurements and their percentage change between preoperative values and values at 1 day, 1 week and 1, 6, 12, 24 months were calculated.

RESULTS

In total, 47 eyes of 47 patients with a mean age of 69 ± 11 years (29 males) were included. Twnty-three patients had Fuchs' endothelial dystrophy (49%) and the remaining 24 had pseudophakic bullous keratopathy (51%). In total, 29/47 eyes underwent UT-DSAEK alone (62%) and 18/47 received combined cataract surgery as a triple procedure (38%). Preoperative donor graft thickness was 92 ± 28 μm. Compared to preoperative values, where graft thickness increased to 194 ± 101.3 μm at 1 day, 151.1 ± 71.4 μm at 1 week, and 108.4 ± 52.5 μm at 1 month. Graft thickness continued to gradually decrease over time until 6 months (91.7 ± 33.6 μm), and then plateaued at 12 months (83.9 ± 25.0 μm), showing minimal changes at 2 years (101.4 ± 37.5 μm).

CONCLUSION

Preoperative DSAEK graft thickness measurements as reported by the eye bank are a valid approximation of DSAEK graft thickness at 6 months after surgery and these measurements tend to stabilize over time up to 2 years after surgery.

Analysis of Corneal Scheimpflug Densitometry and Ocular Wavefront Aberrations Post Descemet Stripping Automated Endothelial Keratoplasty

PURPOSE

To assess the role of corneal densitometry and wavefront aberrations post Descemet stripping automated endothelial keratoplasty (DSAEK) and their correlation with visual acuity.

METHODS

Twenty-seven eyes of 25 patients with nonresolving corneal edema for more than 3 months as a result of Fuchs endothelial corneal dystrophy, pseudophakic bullous keratopathy, or secondary endothelial dysfunction were enrolled in a prospective interventional study and underwent DSAEK. Postoperative evaluation for corneal aberrations, including Higher order aberrations (HOAs) and corneal densitometry (CD), was performed using anterior-segment optical coherence tomography (Avanti RTvue XR; Optovue) and Scheimpflug imaging (Pentacam, Oculus Optikgeräte GmbH, Wetzlar, Germany) at 6 months. A correlation analysis of corneal aberrations, including HOAs and CD, with postoperative best-corrected visual acuity at 6 months was performed.

RESULTS

Mean best-corrected visual acuity (BCVA) improved from 1.67±0.53 log of minimum angle of resolution (logMAR) to 0.2±0.22 logMAR post DSAEK at 6 months (P≤0.0001). At 6 months, mean root-mean-square (RMS) total corneal aberrations (includes HOA and low-order aberration [LOA]), RMS total HOA, and RMS LOA of the central 6-mm zone were 4.99±2.64, 1.80±0.9, and 4.55±2.64, respectively. The mean corneal densitometry from anterior, central, and posterior zones were 39.12±12.77, 23.9±7.2, and 13.54±2.04 gray scale units, respectively. Total anterior aberrations (r=0.051; P=0.006), anterior LOA (r=0.049; P=0.009), total corneal aberrations (r=0.051; P=0.001), total HOAs (r=0.095; P=0.057) and LOAs (r=0.050; P=0.002), and total CD from 0 to 2 mm (r=0.010; P=0.038) and 2 to 6 mm (r=0.014; P=0.018) showed a significant inverse correlation with postoperative BCVA.

CONCLUSION

There was an inverse relationship between post DSAEK BCVA and total corneal HOAs and full-thickness densitometry at 6 months. Scheimpflug imaging with added tools for corneal aberration and densitometry analysis gives further insight into the suboptimal vision achieved despite transparent corneas post DSAEK.

Efficacy of Thin and Ultrathin Descemet Stripping Automated Endothelial Keratoplasty and Influence of Graft Thickness on Postoperative Outcomes: Systematic Review and Meta-analysis

PURPOSE

To conduct a systematic review and meta-analysis on the efficacy of thin and ultrathin Descemet stripping automated endothelial keratoplasty (T-DSAEK and UT-DSAEK, with graft thickness <130 and <100 µm, respectively), depending on graft thickness.

DESIGN

Systematic review and meta-analysis.

METHOD

PubMed, Cochrane Library, Embase, ClinicalTrials.gov, and ScienceDirect databases were searched until October 1, 2021. We computed random-effect meta-analysis on postoperative outcomes of T/UT-DSAEK, stratified by graft thickness (<80 μm, 80-100 μm, and 100-130 μm). The main postoperative outcome was visual acuity (logarithm of the minimum angle of resolution [logMAR]). Secondary outcomes were pachymetry (μm), endothelial cell count (cell/mm²), spherical equivalent (diopter [D]), rebubbling rate (%), and rejection rate (%). Meta-regressions compared postoperative outcomes depending on graft thickness and search for putative confusion factors.

RESULTS

We included 47 articles for a total of 2141 eyes of 2040 patients. T/UT-DSAEK globally improved visual acuity (effect size = -0.38 logMAR [95% confidence interval {CI} -0.46 to -0.30 logMAR]), without difference depending on graft thickness. Overall, pachymetry improved (-60.6 µm [95% CI -101 to -19.7 µm]), endothelial cell count decreased (-1039 cells/mm² [95% CI -1209 to -868 cells/mm²), spherical equivalent resulted in a hyperopic shift (0.74 D [95% CI -0.50 to 1.97 D), the graft rejection rate was 0.2% (95% CI -0.1% to 0.4%), and the rebubbling rate was 8.7% (95% CI 6.8%-10.5%). Grafts >100 μm induced a hyperopic shift. Metaregressions did not demonstrate differences between the 3 groups (<80 μm, 80-100 μm, or 100-130 μm) in any outcomes.

CONCLUSION

All T/UT-DSAEK thickness groups provided similar visual acuity, pachymetry, endothelial cell count, rejection rate, and rebubbling rate regardless of graft thickness. A hyperopic shift was induced by grafts >100 μm.

A Simple 60-Second Swelling Technique for More Consistent Ultrathin DSAEK Graft Preparation

PURPOSE

The purpose of this study is to describe a simple but novel 60-second swelling technique for ultrathin Descemet stripping automated endothelial keratoplasty (DSAEK) graft preparation. In addition, we aim to demonstrate the effectiveness of this technique in obtaining thinner DSAEK grafts more consistently without compromising graft quality.

METHODS

We performed a retrospective case-control study comparing standard DSAEK preparation using an ML7 Microkeratome Donor Cornea System (Med-Logics Inc, Athens, TX) with an additional 60 seconds of stromal swelling with a balanced salt solution after the removal of the epithelium but before the microkeratome pass. Thirty cases using this novel swelling technique were compared with controls matched by age, sex, and precut corneal thickness. Donor characteristics and both precut and postcut graft characteristics were analyzed.

RESULTS

DSAEK grafts prepared with our simple swelling method were approximately 13 μm thinner on average than those prepared with our conventional ultrathin DSAEK preparation technique (P = 0.001). The frequency of grafts less than 100 μm was much greater with swelling (93.3% vs. 63.3% with conventional technique, P = 0.0052). There were no significant differences in postcut cell counts or decrease in cell counts between the groups.

CONCLUSIONS

A simple 60-second swelling technique can yield significantly thinner DSAEK tissue in a more consistent range without a significant impact on the endothelial cell count.

Different graft thicknesses after Descemet stripping endothelial keratoplasty for bullous keratopathy in the two eyes of the same patient

Objective

To describe a very unique case of two Descemet stripping automated endothelial keratoplasty (DSAEK) surgeries performed in both eyes of the same patient with an extremely different graft thickness and overall corneal thickness but with the same corrected distance visual acuity (CDVA) 2 years after surgery.

Case presentation

A 75-year-old woman with bilateral bullous keratopathy (BK) was submitted to DSAEK surgeries in both eyes, first in right and after 6 months in left eye. CDVA was 20/160 in the right eye and 20/63 in the left eye. Corneal thickness evaluated by anterior segment optical coherence tomography was 569 µm in the right eye and 560 µm in the left eye. The root mean square (RMS) was 2.1 in the right and left eyes. Endothelial cell densities were not detectable in both eyes. The estimated precut donor graft thickness from eye bank was 250 and 40 µm in the right and in the left graft, respectively. Two years after surgery CDVA was 20/25 in both eyes. Corneal thickness was 633 µm with a lenticule thickness of 206 µm in the right eye and 439 µm with a lenticule thickness of 48 µm in the left eye. The RMS was 1.7 in the right eye and 1.4 in the left eye. Endothelial cell density was 2.272 cells/mm² in the right and 2.154 cells/mm² in the left eye.

Conclusion

DSAEK was safe and effective in the treatment of BK. In our report, the visual outcome resulted to be poorly related either to donor graft thickness or to postoperative corneal thickness.

Effect of Donor Graft Thickness on Clinical Outcomes after Descemet Stripping Automated Endothelial Keratoplasty

Purpose

To evaluate the effects of donor graft thickness on postoperative best spectacle-corrected visual acuity (BSCVA), refractive outcomes, endothelial cell density (ECD) and function, intraocular pressure (IOP), and postoperative complications after Descemet stripping automated endothelial keratoplasty (DSAEK).

Methods

This retrospective, interventional case series enrolled 77 eyes of 64 patients who underwent DSAEK with or without simultaneous cataract surgery. Clinical outcomes, including BSCVA, refraction, keratometric astigmatism, IOP, and ECD were assessed at the final follow-up examination. Univariate analyses were used to investigate the effects of postoperative donor graft thickness on clinical outcomes and complications.

Results

The mean patient age was 62.3 ± 15.6 years, and the patients were followed for 26.2 ± 20.9 months postoperatively. The mean postoperative central graft thickness was 102.4 ± 31.6 μm. In the univariate analysis, postoperative central graft thickness was significantly associated with postoperative IOP (P = 0.005), central recipient thickness (P = 0.002), and ECD (P = 0.016). No significant association was found for central graft thickness with postoperative BSCVA (P = 0.70), spherical equivalent refraction (P = 0.33), keratometric astigmatism (P = 0.27), graft detachment (P = 0.16), graft decentration (P = 0.17), high IOP (P = 0.53), or endothelial rejection (P = 0.88).

Conclusion

This study failed to demonstrate any significant correlation between graft thickness and BSCVA. Attempting to minimize graft thickness might not have the desired outcome regarding endothelial cell density and function. Increased graft thickness could negatively impact the accuracy of IOP measurements after DSAEK.

Visual Outcomes of Ultrathin-Descemet Stripping Endothelial Keratoplasty versus Descemet Stripping Endothelial Keratoplasty

Purpose

To examine the impact of graft thickness (GT) on postoperative visual acuity and endothelial cell density after ultrathin-Descemet stripping automated endothelial keratoplasty (UT-DSAEK) versus conventional DSAEK.

Methods

The medical records of all patients who underwent DSAEK at our institute during a 2-year period were reviewed. After excluding subjects with low visual potential, 34 eyes were divided into two groups based on the postoperative GT as measured with anterior segment optical coherence tomography (AS-OCT): an UT-DSAEK group (GT ≤ 100 μm, n=13 eyes) and a DSAEK group (GT > 100 μm, n=21 eyes). The groups were compared with regard to best-corrected visual acuity (BCVA), subjective refraction, central corneal thickness (CCT), GT, and endothelial cell density (ECD).

Results

Preoperative BCVA (logMAR) was 1.035 ± 0.514 and 0.772 ± 0.428 for UT-DSAEK and DSAEK, respectively (P=0.072). At 6 months postoperatively, BCVA was 0.088 ± 0.150 following UT-DSAEK and 0.285 ± 0.158 following DSAEK (P=0.001).

Conclusion

DSAEK grafts with a thickness under 100 μm offered better visual outcomes during the early postoperative period.

[Practical assessment of DSAEK in the management of endothelial decompensation following penetrating keratoplasty]

PURPOSE

To report our anatomical and functional results as well as possible complications of the first six Descemet's stripping endothelial keratoplasties (DSAEK) performed in our department for endothelial decompensation after penetrating keratoplasty (PK) METHODS: This was a retrospective and observational monocentric study of six patients with DSAEK after prior PK between January 2015 and July 2016. The data collected were: demographic characteristics (age, sex), ophthalmological comorbidities, initial indication for PK, delay between PK and DSAEK. Best corrected visual acuity (BCVA) preoperatively and at 1, 3 and 6 months postoperatively were collected in Monoyer's and Parinaud scale and converted to log MAR for statistical analysis. The central cornea and graft thickness measured on OCT as well as postoperative complications were also collected.

RESULTS

Mean follow-up duration was 7.2 months [3-10]. The average time after PK was 7.7 years. The mean age of the patients was 67.5 years [32-87]. The initial indication for PK was Fuchs dystrophy (3/6), pseudophakic bullous keratopathy (1/6), corneal laceration (1/6) and other corneal dystrophy (1/6). The authors report one case a combined phaco-DSAEK surgery. The complications observed were: an early graft detachment treated by an additional air bubble injection (1/6) and cystoid macular edema in one other case. The average central corneal thickness decreased from 780μm at day 7 postoperatively to 656μm at 6 months. The average thickness of the graft decreased from 154μm at day 7 to 122μm at 6 months. The mean preoperative BCVA was 1.52 log MAR [1.0-1.7], compared to the mean postoperative BCVA which was 1.5 log MAR [1.1-2.3] at 1 month, 1.15 log MAR [0.5-1.7] at 3 months and 1.1 log MAR [0.7-1.7] at 6 months (data available for 4 patients at 6 months). The recovery of visual acuity was limited in 2 cases, despite corneal clarity restored in all our patients.

DISCUSSION

Our results can be compared to those described in literature. As more penetrating keratoplasty grafts reach the end of their lives, this will allow for more powerful studies.

CONCLUSION

DSAEK on eyes previously treated with PK is a good alternative to a new PK in the case of endothelial decompensation of the graft. The possibility of a posterior lamellar graft allows for faster visual recovery, with preservation of the anterior corneal power and a lower rate of complications.

Evaluation of factors affecting visual acuity after Descemet stripping automated endothelial keratoplasty

PURPOSE

To elucidate the factors affecting visual acuity after Descemet stripping automated endothelial keratoplasty (DSAEK).

METHODS

We reviewed consecutive patients who underwent primary DSAEK for corneal endothelial dysfunction at Inouye Eye Hospital from January 2010 through January 2015 and who had a follow-up of at least 6 months. Fifty-four eyes of 49 patients (24 men and 25 women) were enrolled; the mean age was 72.5 ± 8.7 years. Medical charts were retrospectively examined for best spectacle-corrected visual acuity (BSCVA), intraocular pressure, keratometric value, keratometric cylinder, grade of preoperative corneal edema, preoperative graft thickness, and endothelial cell density (ECD) before and at 1, 3, 6, 12, and 24 months after surgery. A multiple regression analysis was used to evaluate the factors associated with BSCVA at 3, 6 months, and 1 year after surgery. Explanatory variables included age, sex, preoperative factors (BSCVA, degree of corneal edema, donor ECD, and graft thickness), and factors at each time point (keratometric value, keratometric cylinder, and intraocular pressure).

RESULTS

The mean logarithms of the minimum angle of resolution (logMAR) BSCVA preoperatively and at 1, 3, 6, and 12 months after surgery were 1.03 ± 0.49, 0.42 ± 0.26, 0.29 ± 0.21, 0.24 ± 0.20, and 0.22 ± 0.20, respectively. Multiple regression analysis showed that preoperative BSCVA alone was significantly associated with BSCVA at 3, 6, and 12 months.

CONCLUSION

A better preoperative BSCVA was associated with a better BSCVA after DSAEK, which suggests that DSAEK should be considered earlier than stromal changes such as subepithelial fibrosis occurrence.

Determinants of visual quality after endothelial keratoplasty

Endothelial keratoplasty is now favored over full-thickness penetrating keratoplasty for corneal decompensation secondary to endothelial dysfunction. Although endothelial keratoplasty has evolved as surgeons strive to improve outcomes, fewer patients than expected achieve best corrected visual acuity of 20/20 despite healthy grafts and no ocular comorbidities. Reasons for this remain unclear, with theories including anterior stromal changes, differences in graft thickness and regularity, induced high-order aberrations, and the nature of the graft-host interface. Newer iterations of endothelial keratoplasty such as thin manual Descemet stripping endothelial keratoplasty, ultrathin automated Descemet stripping endothelial keratoplasty, and Descemet membrane endothelial keratoplasty have achieved rates of 20/20 acuity of approximately 50%, comparable to modern cataract surgery, and it may be that a ceiling exists, particularly in the older age group of patients. Establishing the relative contribution of the factors that determine visual quality following endothelial keratoplasty will help drive further innovation, optimizing visual and patient-reported outcomes while improving surgical efficacy and safety.

Descemet stripping automated endothelial keratoplasty in Fuchs' corneal endothelial dystrophy: anterior segment optical coherence tomography and in vivo confocal microscopy analysis

Background

To evaluate the in vivo corneal changes using in vivo confocal microscopy (IVCM) and anterior segment optical coherence tomography (AS-OCT) in patients with Fuchs’ dystrophy who underwent Descemet stripping automated endothelial keratoplasty (DSAEK) and the relationship between these changes and the postoperative visual recovery up to 1-year follow-up.

Methods

Before DSAEK and 1 day, 3, 6 and 12 months after surgery 31 patients (39 pseudophakic eyes) underwent a complete ophthalmological evaluation including best corrected visual acuity (BCVA), IVCM (subepithelial haze, interface haze, graft thickness) and AS-OCT (graft thickness).

Results

Graft thickness measurements by AS-OCT were strongly correlated to those obtained using IVCM at every follow-up stage (intraclass correlation coefficient = 0.95 to 0.97 between 3 and 12 months, P < 0.001 for all coefficients). No correlation between BCVA and graft thickness measured by AS-OCT at any follow-up stage was found, while at 3 and 6 postoperative months the correlations between BCVA and preoperative subepithelial haze (r = 0.61, P < 0.001 and r = 0.46, P = 0.002), interface haze (r = 0.51, P < 0.001 and r = 0.46, P = 0.003), postoperative subepithelial haze (r = 0.43, P = 0.004 and r = 0.39, P = 0.001) were significant.

Conclusions

The study confirmed corneal subepithelial haze and interface haze as important factors limiting visual acuity after DSAEK, while graft thickness was not related to BCVA.

A year of cornea in review: 2013

PURPOSE

The goal of this study was to provide an update of significant corneal literature published in 2013.

DESIGN

This study is a systematic literature review.

METHODS

We conducted a systematic review of the English-language literature published from January 1, 2013, to December 31, 2013, using the following PubMed search and Medical Subject Headings terms: cornea transplantation, keratoplasty, Descemet membrane endothelial keratoplasty, Descemet stripping endothelial keratoplasty, cross linking, pre-Descemet's layer, Rho-associated kinase, keratoprosthesis, infectious keratitis, corneal dystrophy, corneal astigmatism, and keratoconus.

RESULTS

This review summarizes relevant and innovative original articles, review articles, and novel techniques from the following journals: American Journal of Ophthalmology, British Journal of Ophthalmology, Cornea, Graefe's Archive for Clinical and Experimental Ophthalmology, Investigative Ophthalmology & Visual Science, JAMA Ophthalmology, Journal of Cataract and Refractive Surgery, Journal of Refractive Surgery, and Ophthalmology. Case reports, abstracts, letters to the Editor, and unpublished work were excluded, as well as articles e-published ahead of print in 2012 that were discussed in the previous review. One hundred twenty-seven articles met the criteria for this review.

CONCLUSIONS

This review summarizes significant cornea-related literature from 2013.

Does thickness matter: ultrathin Descemet stripping automated endothelial keratoplasty

PURPOSE OF REVIEW

Descemet stripping automated endothelial keratoplasty (DSAEK) has become worldwide the procedure of choice for the replacement of diseased corneal endothelium. More recently, ultrathin DSAEK (UT-DSAEK) has been introduced to guarantee better visual outcomes preserving good donor graft manipulation.

RECENT FINDINGS

As DSAEK may still have major challenges such as suboptimal visual acuity and relatively slow visual rehabilitation, fairly new techniques such as UT-DSAEK and Descemet membrane endothelial keratoplasty (DMEK) have been introduced to allow much quicker and optimal visual rehabilitation. This article goes through the most recent findings and results of these techniques.

SUMMARY

UT-DSAEK is a procedure that shares the improved visual outcome and lower immunologic rejection rate of DMEK over DSAEK, while minimizing all types of postoperative complications. In addition, similar to DSAEK and unlike DMEK, UT-DSAEK can be performed in all types of eyes, even in those with complicated anatomy or poor anterior chamber visualization.