2022 Eye Banking Statistical Report—Executive Summary

Abstract

2022 ANALYSIS OF SURGICAL USE AND INDICATIONS FOR CORNEAL TRANSPLANT The 2022 Eye Banking Statistical Report of the Eye Bank Association of America (EBAA) includes information on all EBAA member eye banks (55 US and 11 international) and EBAA-accredited entities (1 US) reporting data for the 2022 calendar year and represents an essentially complete picture of eye banking activity in the United States. Data on utilization are provided for all tissue recovered by EBAA eye banks, and indications for surgery are provided for all tissue used for transplant. Details of This Year's Analysis Starting in 2017, the summarized data for Indications for Transplant were segregated by where the tissue from domestic eye banks was used—domestically or internationally. Before then, the analysis of indications for transplant came from domestically and internationally used corneas supplied by US eye banks. However, the validity of the conclusions drawn about tissue utilization and indications for transplant was diminished by the large number of unknowns, mostly from corneas distributed internationally. The percentage of unknown indications for use in US tissue shipped internationally for transplant was 61.7% in 2021 and 58.9% in 2022 (Table 8). The large number of unknowns makes it difficult to draw reasonable conclusions about what the tissue was used for or what the indication for surgery was. For this reason, the indications for transplant data (Table 9) are presented only for domestic utilization of corneas supplied by US eye banks, where the unknown percentage was 11.4% in 2022. Because 28.7% of US tissue is shipped internationally for PK, ALK, or EK procedures, the international unknowns represent a large subset (11,189 of 66,131 or 16.9%) of data on utilization of tissue recovered in the United States. Donations and Tissue Supply In 2022, total donors were down 3.6% and total corneas donated were down 3.3% compared with 2021 (Table 1). Total corneal grafts (transplanted or long-term preserved) using tissue from US banks were down 0.6% in 2022 compared with 2021. Intermediate-term preserved corneas, which included all refrigerated tissue stored in hypothermic corneal storage solution used for full-thickness and lamellar procedures, decreased 0.3% from 72,038 in 2021 to 71,835 in 2022. TABLE 1. - Total Donations and Distribution of Tissue in 2022 Domestic transplants increased 1% in 2022, but international transplants (using tissue from the US banks) were down 3% and accounted for the slight overall drop in total transplants using intermediate-term preservation medium. Both domestic and international transplant numbers still lag behind pre-COVID numbers (Fig. 1).FIGURE 1.: Corneal transplants supplied by US banks, 2018 to 2022.There was a storage solution supply crisis in 2022 that contributed to the decrease in the number of corneas recovered and transplanted. All eye banks adjusted to the shortage by seeking other brands of intermediate-term storage medium and/or exchanging medium with other eye banks to service daily needs. Eye banks also tightened their criteria for recovering tissue to maximize their utilization of the limited supply of storage solution available for transplantable tissue. This reduction in the overall number of corneas recovered depressed the number of corneas exported internationally or preserved long-term (since local needs are usually met first). Although the shortage was a major source of concern for the Association, it did not significantly affect the number of corneas transplanted domestically in 2022. Comparing with prepandemic rates (2022 vs. 2019), domestic use of tissue was down 3.4% (1739 corneas), while international use of tissue was down 21.4% (6164 corneas). Corneas distributed in long-term preservation medium decreased 63.7% in 2022. Most corneas distributed in long-term storage medium are used for glaucoma drainage devices. The decrease is discussed in the subsequent section “Tissue for glaucoma shunts,” page 10. The total numbers for domestic and international transplants provided by US eye banks for the past 21 years can also be seen in Figure 2 and Table 2. In 2022, US eye banks collectively exported approximately 28% of tissue recovered in the United States to international surgeons. This trend, averaging approximately 30% over the past 12 years, demonstrates the continuing commitment of US eye banks to help meet international eye banks needs to help reduce global blindness from corneal disease.FIGURE 2.: Total corneal transplants supplied by US eye banks in intermediate-term storage medium, 1991 to 2022, stratified by domestic and international use. TABLE 2. - Corneal Transplants Supplied by US Eye Banks, 1991 to 2022 Table 2 presents the data that are plotted in Figure 2. The annual totals show both domestic and international disposition of tissue. Keratoplasty tissue usage in the United States dropped approximately 20% in 2020 from COVID-19. Both domestic and international tissue use in 2022 remains down 5% compared with pre-COVID levels. Tissue Utilization From US Eye Banks Combined domestic and international utilization of tissue supplied by US eye banks over the past 5 years is presented in Table 3. There was a decrease in all keratoplasty procedures in 2022 except endothelial keratoplasty. Total grafts in 2022 decreased slightly (0.6%) from 79,641 to 79,126 in 2021. Penetrating keratoplasty (PK) numbers decreased 5.5% from 30,412 to 28,728 in 2022. Table 3 presents the continuation of the decline in PK procedures worldwide observed since 2005. Tissue used for endothelial keratoplasty (EK) procedures, including both Descemet stripping endothelial keratoplasty (DSEK) and Descemet membrane endothelial keratoplasty (DMEK), increased 1.8% from 35,532 in 2021 to 36,173 in 2022, the highest number of annual EK procedures to date. Anterior lamellar keratoplasty (ALK) procedures decreased 5.9% from 1307 in 2021to 1230 in 2022 and is now just over half the pre-COVID ALK numbers. The number of corneas used for keratolimbal allograft (KLA) decreased 9.0% from 134 to 122 in 2022. Corneas used for keratoprosthesis decreased 22.3% from 175 in 2021 to 136 in 2022. The 2022 number is approximately half the 344 K-Pro procedures performed in 2017. The number of corneas used for ALK, KLA, and K-Pro procedures remains relatively small: These 3 procedures combined used just 1.9% of the total tissue supplied by US eye banks for domestic and international use in 2022 (see Table 3). TABLE 3. - Utilization of Tissue Supplied by US Eye Banks for Domestic and International Use, 2018 to 2022 US eye banks also provided 20,557 ocular tissues for research and training, continuing their support of education and training in cornea surgery, and helping to develop future therapies. Domestic Use of Keratoplasty Tissue From US Eye Banks Trends in the domestic use of tissue (tissue supplied by domestic eye banks used in the United States) are presented in Table 4. The number of penetrating grafts performed in the United States using intermediate-term preservation medium decreased 5.6% in 2022 from 15,402 in 2021 to 16,269. Decreasing PK numbers have been noted over the previous 16 years from a high of 42,063 in 2005. EK procedures in 2022 increased 2.4% from 30,098 in 2021 to 30,812 in 2022 and have surpassed pre-COVID levels. Separate DMEK and DSEK numbers are discussed in Table 5. The number of corneas used domestically for EK has increased every year since tracking started in 2005, surpassing PK in 2012 (Fig. 3). TABLE 4. - Domestic Use of Intermediate-Term Preserved Tissue From US Eye Banks, 2013 to 2022 TABLE 5. - US Eye Banks, Domestic Endothelial Keratoplasty Numbers, 2016 to 2022 FIGURE 3.: Domestic PK versus EK versus ALK surgery trends, 2005 to 2022.ALK procedures in the United States decreased 12.5% from 544 to 476 in 2022. DALK procedures are still well below pre-COVID levels. KLA and K-Pro procedures have been essentially flat in the United States over the past 10 years. Combined, ALK, KLAL, and K-Pro made up 1.8% of intermediate-term preserved tissue use in the United States in 2022, the same percentage as in 2021 and the same percentage of combined domestic and international data.FIGURE 4.: The number of domestic PK, DSEK, and DMEK procedures, using tissue from US eye banks, are shown monthly for the past 5 years. In this graph, PK and DSEK are decreasing slightly, and DMEK is increasing. In 2022, the number of PK, DSEK, and DMEK procedures performed quarterly were essentially equal.FIGURE 5.: The annual numbers for domestic PK (15,835), DSEK (15,544), and DMEK (15,248) were essentially the same in 2022.The relative frequency of PK, EK, and ALK procedures performed in the United States over the past 18 years can be seen in Figure 3. PK grafts have decreased since their peak in 2005 due to the increased use of endothelial keratoplasty to correct endothelial disease. In 2012, the number of EK procedures exceeded PK. Endothelial keratoplasty numbers include both DSEK (DSEK and variants, such as DSAEK, pre-Descemet's endothelial keratoplasty, and DMEK). Table 5 illustrates that by the end of 2022, DMEK procedures had nearly equaled the number of DSAEK procedures and were wholly responsible for the increase in endothelial keratoplasty numbers since 2014. DSAEK numbers have declined slightly over the past 6 years as more DMEK procedures were performed for endothelial disease. DMEK procedures increased from 14,128 in 2021 to 15,248 in 2022 (7.9%), whereas DSEK procedures declined 2.5% in that same period (Figs. 4 and 5). However, the number of DSAEK procedures (15,544) still exceeded the number of DMEK procedures (15,248) performed in 2022. It is important to note that DMEK use climbed even as total transplant numbers dropped. This suggests that DMEK activity growth at the expense of PK and DSAEK activity remains a strong trend and indicates an ever-growing appetite for tissue from donors 50 years or older without the history of diabetes. Data for preloaded endothelial keratoplasty were collected starting in 2021 (Table 6). TABLE 6. - US Eye Bank Use of Preloaded Tissue for Endothelial Keratoplasty, 2022 Most surgeons (94.5%) (18 to 1) loaded their own DSEK tissue but preferred preloaded DMEK tissue (85.6%) almost 6 to 1. Tissue for Glaucoma Shunts The use of eye bank tissue to cover glaucoma shunt procedures is presented in Table 7. Corneal tissue is still the most popular material glaucoma surgeons use to cover shunt hardware, but there has been a decreasing trend in the number of glaucoma shunts since 2016 (Fig. 6). In 2017, the Current Procedural Terminology code for additional tissue to cover shunts was deleted, so the cost of tissue was bundled in the procedure; there was less incentive for surgeons to use extraneous tissue for shunt repair. In addition, the explosive increase in the use of microinvasive glaucoma surgery devices (MIGS) by ophthalmic surgeons over the past 4 years has led to a decrease in the number of tube shunts. TABLE 7. - Ocular Tissue Used for Glaucoma Shunt Patching, 2013 to 2022, Including Data From Both Domestic and International Use of Tissue From US Eye Banks FIGURE 6.: Tissue used for glaucoma shunt patching, 2013 to 2022.Corneas in long-term storage still make up approximately 2/3 of all ocular tissue used for shunt patching, but fewer shunts are responsible for the large decrease in the number of corneas preserved in long-term storage in 2022 (see page 1 of this report). Indications for Keratoplasty The indications for the 3 main keratoplasty procedures performed using corneas provided by US eye banks, both for domestic and international use, are presented in Table 8, Indications for Corneal Transplant Reported by US Banks, 2022. The large number of “unknowns” has been a persistent problem and compromises conclusions drawn from that data. For example, 65.5% of tissue shipped internationally for penetrating keratoplasty has no diagnosis provided, and 20.3% of PK procedures in the United States have no diagnosis. The large number of unknowns limits the validity of conclusions that can be drawn on indications for transplant, and only domestic data are used for statistical analysis of indications in Table 9. TABLE 8. - Indications for Corneal Transplant, Reported by US Banks, 2022 TABLE 9. - Domestic Indications for Keratoplasty Reported by US Eye Banks in 2022 A side-by-side comparison of the information in Table 8 is shown in Figure 7A (domestic) and Figure 7B (international). Note the large overall number of “unknowns” (59%) for international use.FIGURE 7.: 2022 keratoplasty indications, US eye banks: Domestic versus International distribution. A and B, Surgical indications for 2022 domestic (A, right panel) and international (B, left panel) tissue distribution for keratoplasty. Note line Z: The high number of unknowns. A—postcataract surgery edema. B—ectasias/thinning. C—endothelial dystrophies. D—repeat corneal transplant. E—other degenerations/dystrophies. F—refractive. G—microbial keratitis. H—mechanical (non-surgical) or chemical trauma. I—congenital opacities. J—pterygium. K—noninfectious ulcerative keratitis, thinning or perforation. L—other unknown causes of corneal opacification or distortion. M—other causes of endothelial dysfunction. Z—unknown or unreported.Table 9, Indications for Transplant, Domestic Utilization of Tissue from US Eye Banks, on the following page, is arranged into 4 basic categories for which keratoplasty is performed: 1) endothelial cell failure, 2) stromal or full-thickness (nonendothelial) disease, 3) regrafts, and 4) unknown. The specific diagnosis, or indication for transplant, is listed in each general category. Endothelial disease is still the overall leading indication for domestic keratoplasty. A total of 28,143 of 47,123 (59.7%) keratoplasty procedures in the United States in 2022 were performed for endothelial failure (Fuchs endothelial dystrophy, postcataract surgery edema, and other causes of endothelial cell failure). For the treatment of endothelial disease, 89.9% of grafts were EK and 10.1% were PK. Repeat transplants (6457 in 2022, 13.7% of all grafts) were the third category. Specific regraft rates were PK 19.1%, EK 11.0%, and ALK 6.5%, all nearly identical to last year. Stromal disease (7,141, 15.2%) was second and includes keratoconus and ectatic disorders, dystrophies and degenerations, corneal opacities, iatrogenic refractive errors, opacity from microbial keratitis, and other causes of corneal distortion. In total, 15.2% of all keratoplasty procedures were performed for stromal or full-thickness disease: 94.3% were PK and 5.7% were ALK. Regrafts (6,457, 13.7%) were the third most common indications for transplant. Unknowns (5,382, 11.4%) were the fourth most common indication. Unknowns were third last year, as the Association and its membership have taken on the challenge of determining the root cause of unknown information and addressing it. Notably, a small number of eye banks are responsible for a large portion of unknown diagnosis information. Overall, Fuchs dystrophy was the leading specific diagnosis for keratoplasty in the United States in 2022 (18,561, 39.4%), as has been the case for the past 9 years. In total, 94.5% of patients with Fuchs dystrophy underwent EK, and 5.5% had PK. Regrafts were the second most frequent individual diagnosis provided (6,457), and “other causes of endothelial dysfunction” were third (5,597, 11.9%). Unknowns were fourth (5,382, 11.4%), and “postcataract surgery corneal edema” was fifth (3,985, 8.5%). As in past years, “keratoconus and other ectasias” was the sixth most frequent indication for transplant in 2022. There were 2334 keratoplasty procedures for keratoconus in 2022, continuing a ten-year trend of declining keratoplasty procedures for keratoconus from a high of 8071 in 2011. Penetrating keratoplasty continues to be the preferred surgical procedure for the treatment of corneal ectasia by almost 11 to 1 (PK vs. ALK). There were 2128 (91.2%) PKs and 206 (8.8%) ALK procedures for keratoconus in 2022. The technical difficulty of ALK and uncertainty over reimbursement continue to hold this ratio essentially unchanged for the past 6 years. Treatment of keratoconus by cross-linking and improved technology in rigid gas permeable contact lens fitting are likely responsible for the decreasing number of keratoplasty procedures for corneal ectasia. In 2020, the number of primary penetrating keratoplasty for keratoconus dipped for the first time below the number of PKs for regraft (see Fig. 8). This year, there were 3030 PK regrafts and 2334 grafts for keratoconus. PK for both keratoconus (red) and for postcataract surgery corneal edema (dark blue) has been decreasing over the past 10 years because of cross-linking and because of newer rigid gas permeable contact lens, a trend present for the past 8 years. PK for postcataract surgery corneal edema has also dropped as more surgeons become comfortable with endothelial keratoplasty.FIGURE 8.: Ten-year trends in common surgical indications for penetrating keratoplasty.A summary for the trends in PK, EK, and ALK surgical indications over the past 8 years is shown in the following 3 figures for PK, EK, and ALK. All 3 graphs show a decrease in the number of procedures due to COVID-19 in 2020, but a rebound in 2021 and 2022 (Figs. 8, 10, and 11). The number of PK procedures continues to drop each year going back to 2005, but the number of PK procedures for regrafts and PK for Fuchs dystrophy remain constant. There is a large pool of PK patients from the prevalence of the procedure over the past 50 years that still require medical attention. Although the number of PK for endothelial dystrophies is small, a finite percentage of advanced Fuchs patients have stromal opacification and are better served with a full-thickness graft than endothelial replacement alone. The number of endothelial keratoplasty procedures continues to rise each year as more new patients have this procedure performed for endothelial dysfunction. The number of regrafts remains constant; since more people are having the procedure, the percent of patients needing regraft is actually diminishing over time. The leading indication for ALK has been corneal ectasias, but as fewer patients require keratoplasty for keratoconus and other ectasias, the number of ALK procedures has trended downward over the past 8 years (Fig. 11). Possible reasons for this decline include the technical difficulty of successful DALK, billing discrepancies as DALK is not reimbursed as much as PK, and the effectiveness of cross-linking and current rigid gas permeable contact lenses in mitigating the need for surgery in keratoconus patients. Conclusions The leading indication for keratoplasty in 2022 was endothelial disease (59.7% of grafts, see Table 9). Corneal surgeons requested preloaded DSEK tissue 5.5% of the time and preloaded DMEK tissue 85.65% of the time. The number of PK (15,835), DSAEK (15,544), and DMEK (15,248) procedures were essentially the same in 2022 (Fig. 5 and Tables 4 and 5). PK procedures in the United States have declined from a high of 42,063 in 2005 to 15,835 in 2022. PK is the most common procedure used for corneal ectasia (91.2%), but PK for ectasias has trended lower for the past 9 years due to cross-linking and newer RGP/scleral contact lenses (Fig. 7 and Table 9). The number of anterior lamellar keratoplasty, keratolimbal allografts, and keratoprosthesis procedures have been essentially flat over the past 9 years. These 3 procedures combined make up 1.8% of all keratoplasty procedures performed in the United States (Table 4). Corneas in long-term storage solution are the most common ocular tissue (66%) used by glaucoma surgeons to cover glaucoma drainage devices (Fig. 9), but the number of corneas used to cover drainage devices decreased by more than 50% this year, continuing a downward trend in the use of glaucoma shunt devices since 2016 due to lack of reimbursement for donor tissue and the increased use of MIGS devices in patients with glaucoma (Table 7). There was no recipient diagnosis for 59% of US eye bank tissue shipped internationally (Table 8, Fig. 7b). Eye banks still need to diligently try to collect recipient information on tissue used domestically and internationally, as well as when exporting tissue to other eye banks (Figs. 10, 11). FIGURE 9.: Tissue used for glaucoma shunt patching in 2022. Corneas in long-term storage medium still comprise 64.6% of all ocular tissue used to cover glaucoma, although the total number of corneas used for shunt procedures decreased 56.2% from 15,705 in 2021 to 6882 in 2022.FIGURE 10.: Ten-year trends in common surgical indications for endothelial keratoplasty procedures.FIGURE 11.: Ten-year trends in surgical indications for ALK procedures.SPECIAL STATISTICAL REPORT ADDENDUM Special Statistical Report Addendum: The Dual Impact of the COVID-19 Pandemic and Storage Solution Supply Crisis of 2022 The calendar year 2021 showed growth following the devastating impact of the COVID-19 pandemic in 2020. 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