Endothelial cell density in porcine corneas after exposure to hypotonic solutions

Purpose To evaluate exposure to sucrose solution (1.8%) and hypotonic balanced salt solution (BSS) for its effects on endothelial cell density of porcine corneas.Methods Two groups of central discs from pig corneas were organ-cultured for 24 h. Twelve corneas per group were exposed to sucrose solution (1.8%) or hypotonic BSS for 4 min each. The paired corneal discs were not treated and served as controls. After further organ culture with and without dextran for 48 h, corneal endothelium was stained with alizarin red and examined by light microscopy. The endothelial cell densities were determined manually on three central images.Results The endothelial cell density differed significantly between corneas exposed to sucrose and the control corneas (3982±382 cells/mm² and 4360±331 cells/mm² respectively, and 3876±364 cells/mm² versus 4374±168 cells/mm² respectively with 6% dextran). In contrast, the endothelial cell density did not differ significantly between corneas exposed to hypotonic BSS and the control corneas (4374±296 cells/mm² and 4317±193 cells/mm² respectively, and 4348±151 cells/mm² versus 4426±175 cells/mm², respectively with 6% dextran).Conclusions Exposure to 1.8% sucrose for 4 min induces a significant endothelial cell loss of 10% on average, whereas exposure to hypotonic BSS did not significantly influence the endothelial cell density.Presented in part at the annual meeting of the Deutsche Opthalmologische Gesellschaft (DOG), Berlin, 2005.     

羟乙基淀粉130/0.4对器官培养法保存兔角膜的脱水作用

目的：研究羟乙基淀粉的最新剂型HES 130/0.4对器官培养保存角膜的持续脱水效果。

方法：20对配对兔角膜,一半于含10% HES 130/0.4的ACF培养液中保存28d作为实验组,不再单独脱水; 另一半于ACF培养液中保存28d后再葡聚糖T500脱水48h作为对照组。内皮细胞活性和植片质量评估指标包括：内皮细胞计数、角膜厚度和含水量、角膜透明度和后弹力层皱褶程度、内皮层中肌动蛋白微丝(filament actin,F-actin)的表达,及透射电镜下内皮细胞超微结构的变化。

结果：保存结束时,实验组植片明显较薄,角膜透明度和皱褶程度也优于对照组,内皮细胞密度为2371±159个/mm²。对照组继续脱水后,角膜厚度、含水量和透明度与实验组间差别变小,内皮细胞密度却降至2138±182个/mm²。免疫印迹法证实F-actin在两组内皮层都有表达,实验组的F-actin表达水平更高。电镜下实验组的细胞超微结构改变较小。

结论：HES 130/0.4的细胞毒性小,可成为器官保存液中的持续添加组分,不仅避免角膜过度水肿,还简化了保存程序,减轻了感染风险,有希望成为新型角膜脱水剂。     

Properties of Corneas Reconstructed with Cultured Human Corneal Endothelial Cells and Human Corneal Stroma

Purpose

To examine the properties of corneas tissue-engineered with cultured human corneal endothelial cells (HCEC) and human corneal stroma.

Methods

Primary HCEC cultures were established from endothelial cell layer explants and propagated on culture dishes coated with bovine corneal endothelial extracellular matrix. A cell suspension of HCEC at the fifth passage was transferred onto human corneal stroma deprived of endothelial cells, and the corneas were gently centrifuged to enhance cell attachment. The cell density of the tissue-engineered corneas was examined after staining with alizarin red and trypan blue. The tissue-engineered corneas were histologically examined by light and electron microscopy. The pump function of the tissue-engineered corneas was measured using an Ussing chamber.

Results

The mean endothelial cell density of four tissue-engineered corneas was 2380 ± 264 cells/mm² (mean ± SD). HCEC on the tissue-engineered corneas had a morphology similar to HCEC in vivo. The pump function parameters of the tissue-engineered corneas were 55%–75% of those of normal corneas.

Conclusions

HCEC on the tissue-engineered corneas have morphology and cellular density similar to HCEC in vivo, whereas the pump function of the tissue-engineered corneas was lower than in normal corneas. Jpn J Ophthalmol 2005;49:448–452 © Japanese Ophthalmological Society 2005     

Transplant endothelium and measuring corneal thickness after non-high-risk keratoplasty with briefly or long-term preserved corneal donor tissue]

PURPOSE: The corneal endothelial cell density is essential for the pump function and the transparency of grafts after penetrating keratoplasty (PK). The purpose of this study was to assess corneal endothelial cell density after non-high-risk PK and to check for possible correlations with storage parameters of the donor corneas using two different storage methods. PATIENTS AND METHODS: Endothelial cell density (specular microscope EM 1100, TOMEY, Erlangen) and central corneal thickness (ultrasonic pachymetry SP-2000, TOMEY, Erlangen) were assessed 6 weeks, 3, 6, 9 months and one year postoperatively in 168 non-high-risk PKs. Short-term-preserved donor corneas were used in 89 patients, whereas in 79 patients organ-cultured corneas were used. The donor trephination was performed from the epithelial side using an artificial anterior chamber. The postoperative treatment with topical steroids was standardized. The mean donor post-mortem time was 9.6 +/- 8.0 hours for short-term-preserved and 17.6 +/- 10.5 hours for organ-cultured corneas (p < 0.0001). The storage time was 71 +/- 49 and 380 +/- 167 hours (p < 0.0001), respectively. RESULTS: Endothelial cell density did not differ significantly between the two storage methods (p > 0.05). At 6 weeks postoperatively, the mean endothelial cell density was 2042 +/- 675 cells/mm2 for short-term-preserved corneas and 1972 +/- 522 cells/mm2 for organ-cultured corneas (p = 0.7). Endothelial cell density did not decrease significantly (p > 0.05) within the observation period of 12 months in both groups (after 12 months: 1868 +/- 957 cells/mm2 and 1638 +/- 643 cells/mm2, respectively). The mean corneal thickness was 542 +/- 50 microns for short-term-preserved and 541 +/- 55 microns for organ-cultured corneas and remainded unchanged during the follow-up of 12 months (542 +/- 42 microns and 521 +/- 43 microns, respectively). Neither the group of short-term-preserved corneas nor organ-cultured corneas showed a significant correlation between endothelial cell density or central cornea thickness with post-mortem time or with storage time of the donor corneas at any postoperative stage (p > 0.1). CONCLUSION: During the first year after PK, only a small decrease in endothelial cell density was observed in comparison with the 6-weeks finding. The storage method does not seem to affect the short-term changes of endothelial cell density. Further long-term studies are necessary to assess the clinical relevance of these observations.     

In vivo corneal confocal microscopic analysis in patients with keratoconus

AIM:To quantify corneal ultrastructure using laser scanning in vivo confocal microscopy (IVCM) in patients with keratoconus and control subjects.METHODS: Unscarred corneas of 78 keratoconic subjects without a history of contact lens use and 36 age-matched control subjects were evaluated with slit-lamp examination (SLE), corneal topography and laser scanning IVCM. One eye was randomly chosen for analysis. Anterior and posterior stromal keratocyte, endothelial cell and basal epithelial cell densities and sub-basal nerve structure were evaluated.RESULTS: IVCM qualitatively demonstrated enlarged basal epithelial cells, structural changes in sub-basal and stromal nerve fibers, abnormal stromal keratocytes and keratocyte nuclei, and pleomorphism and enlargement of endothelial cells. Compared with control subjects, significant reductions in basal epithelial cell density (5817±306 cells/mm² vs 4802±508 cells/mm², P<0.001), anterior stromal keratocyte density (800±111 cells/mm² vs 555±115 cells/mm², P<0.001), posterior stromal keratocyte density (333±34 cells/mm² vs 270±47 cells/mm², P<0.001), endothelial cell density (2875±223 cells/mm² vs 2686±265 cells/mm², P<0.001), sub-basal nerve fiber density (31.2±8.4 nerves/mm² vs 18.1±9.2 nerves/mm², P<0.001), sub-basal nerve fiber length (21.4±3.4 mm/mm² vs 16.1±5.1 mm/mm², P<0.001), and sub-basal nerve branch density (median 50.0 (first quartile 31.2 - third quartile 68.7) nerve branches/mm² vs median 25.0 (first quartile 6.2 - third quartile 45.3) nerve branches/mm², P<0.001) were observed in patients with keratoconus.CONCLUSION: Significant microstructural abnormalities were identified in all corneal layers in the eyes of subjects with keratoconus using IVCM. This non-invasive in vivo technique provides an important means to define and follow progress of microstructural changes in patients with keratoconus.     

Human grafts preserved at +37 degrees C. Initial clinical results

This study reports the clinical use of donor corneas stored at +37 degrees C in organ culture medium. Twenty-five penetrating keratoplasties were performed. The mean storage time of organ-cultured donor corneas was 12.3 days (3-21). The follow up of the patients was 12 months. The criteria for the survival of corneal grafts was mean central corneal thickness, clarity of the cornea and mean endothelial cell density. The graft survival was 92% at 12 months. The mean central corneal thicken was 0.54 mm. The mean endothelial cell density was 1625 cells/mm2. The mean decrease in endothelial cell density at 12 months was 40.6%.     

共焦显微镜观察青光眼患者角膜内皮细胞的变化

目的：利用共焦显微镜观察青光眼患者角膜内皮细胞密度及形态学变化,探讨角膜内皮细胞损伤原因,采取必要措施进行保护。
　　方法：选取不同类型青光眼患者97例143眼,与患者年龄相匹配的正常人20例40眼。采用共焦显微镜观察、测量角膜内皮细胞密度和细胞面积、细胞变异系数等各项指标,分析比较不同类型青光眼各组角膜内皮细胞各项测量指标的差异。
　　结果：年龄相匹配正常人组角膜内皮细胞密度2893.88±255.026个/mm2,急性闭角型青光眼组1674.11±683.95个/mm2,开角型青光眼组2687.22±391.87个/mm2,慢性闭角型青光眼组2706.97±351.27个/mm2。,在各项指标中,角膜内皮平均密度、平均面积均有统计学意义(F=62.950,8.795;P值均为0.000),其中尤以急性闭角型青光眼组与各组相比差异显著。
　　结论：急性闭角型青光眼发作眼角膜内皮细胞各项指标明显低于正常人。开角型与慢性闭角型青光眼角膜内皮细胞与正常人相比,有差别但不显著。眼压升高时限是损伤角膜内皮细胞主要因素。     

Repopulation of denuded murine Descemet’s membrane with life-extended murine corneal endothelial cells as a model for corneal cell transplantation

· Background: Corneal endothelial cell transplantation has been an intriguing concept as an alternative to full-thickness penetrating keratoplasty. Using a murine corneal transplantation model, we sought to establish the optimal conditions to repopulate, ex vivo, denuded murine Descemet’s membrane with life-extended cell cultures of murine corneal endothelial cells. These ex vivo repopulated corneas were used as donor corneas in a murine orthotopic corneal transplantation model to assess, in vivo, the function of the transplanted, life- extended murine corneal endothelial cells (MCEC). · Methods: Mouse corneas were surgically trephined and the native corneal endothelium was removed mechanically using a sterile cotton swab. Cultured murine corneal endothelial cells (life extended by expression of the SV40 large T antigen) were added onto the denuded Descemet’s membrane and allowed to attach in culture at 37°C. Evidence of corneal cell attachment to Descemet’s membrane was determined between 1 and 8 h by scanning and transmission electron microscopy. Donor life-extended corneal endothelial cells were labeled with a fluorescent dye to allow tracking of the donor cells following seeding onto denuded Descemet’s membrane. In four independent experiments, the Descemet’s repopulated corneas were placed into syngeneic mice and evaluated for corneal clarity after 6 weeks. · Results: We could detect attachment of the life-extended murine CEC by scanning and transmission electron microscopy to denuded Descemet’s membrane. The optimal time for adherence was 2 h and these repopulated corneas were used as donors in a murine model of penetrating keratoplasty. Of 20 mice evaluated after 6 weeks, 4 displayed corneal clarity, and fluorescent evaluation demonstrated that only the donor corneal endothelial cells were present. · Conclusions: This experimental protocol establishes that ”life- extended” MCEC can bind to Descemet’s membrane ex vivo and form a distinct monolayer. The repopulated Descemet’s membrane allowed us to directly test the hypothesis that cultured life-extended corneal endothelial cells are functional when reintroduced into an in vivo milieu and provides evidence that specific corneal endothelial cell transplantation may be a viable alternative to pentrating keratoplasty. Received: 21 July 1999 Accepted: 22 September 1999     

Comparison of corneal endothelial changes after use of different adjuncts during lens implantation

To evaluate postoperative changes in corneal endothelial cell density, we conducted a retrospective study in 34 patients (35 eyes). Patients underwent extracapsular cataract extraction and posterior chamber lens implantation using an air bubble (23 eyes), sodium hyaluronate (Healon) (6 eyes), or air bubble plus sodium hyaluronate (6 eyes). The endothelial cell density of all eyes decreased from 2496±341 cells/mm² preoperatively to 1539±371 cells/mm² 1 month postoperatively. The endothelial cell loss rate was 21%, 31%, and 29% in the air bubble, sodium hyaluronate, and air bubble plus sodium hyaluronate groups, respectively (P>.05).     

Cryopreservation of human donor corneas with dextran

PURPOSE: To assess freeze-thaw-induced endothelial cell loss by using phase-contrast microscopy and early morphologic changes within each layer of human donor corneas by using confocal microscopy. METHODS: Twenty-eight human corneas were cryopreserved in minimum essential medium containing 10% dextran with a molecular weight (MW) of 500,000 as an extracellular cryoprotectant, at a cooling rate of 1 degrees C/min and stored in liquid nitrogen at -196 degrees C. After thawing, the tissue was organ cultured to detect latent cell damage. In 22 of the corneas, the endothelial layer was subjected to routine phase-contrast microscopy after 24 hours of organ culturing. The other six specimens were evaluated layer by layer in a scanning slit confocal microscope after 6, 24, and 48 hours of organ culturing. RESULTS: Before cryopreservation, the mean +/- SD numerical density of endothelial cells was 1940 +/- 220 cells/mm(2). After cryopreservation and subsequent organ culturing, the endothelial cell density decreased to 1300 +/- 360 cells/mm(2), and two of the corneas had a completely necrotic endothelium (P = 0.001). Confocal microscopy revealed all corneal layers in each of the six specimens examined to be structurally integral after 48 hours of organ culturing. Although the reflectivity of some of the keratocytes was enhanced, there were no signs of keratolysis. CONCLUSIONS: The present study demonstrates that each corneal layer is capable of regaining its structural integrity after cryopreservation in the presence of dextran. Because the freeze-thaw-induced endothelial cell loss is still highly variable, the technique must be further refined before it can be applied clinically.     

Decreased endothelial cell survival after transplantation of corneas preserved by three modifications of corneal organ culture technique

We placed human donor corneas in M-K medium at 4 degrees C for 24 hours, cultured them in minimal essential medium at 34 degrees C for two to five weeks, and then either (1) placed the corneas in M-K medium at 4 degrees C for 48 hours before transplantation (Group 1, 47 eyes); (2) placed the corneas in M-K medium at 4 degrees C for 16 hours before transplantation (Group 2, 17 eyes); or (3) transplanted the corneas without postculture cooling to 4 degrees C (Group 3, 11 eyes). We compared the corneas preserved by organ culture with an equal number of corneas transplanted during the same period, but preserved only in M-K medium at 4 degrees C for one to four days. The central endothelial cell losses noted two months after keratoplasty were significantly greater in the organ-cultured corneas than in the M-K-preserved corneas in each of the three groups. The mean endothelial cell loss in the 11 organ-cultured corneas in Group 3 was significantly less than that in the 64 organ-cultured corneas in Groups 1 and 2. The corneas in Group 1 were also examined one year after keratoplasty, and the cell losses in the organ-cultured grafts remained significantly greater than those in the M-K-preserved grafts.(ABSTRACT TRUNCATED AT 250 WORDS)     

Central corneal thickness and Diaton transpalpebral tonometry

Background To examine the effects of central corneal thickness on the measures obtained from transpalpebral tonometry (Diaton), and to identify correlations between intraocular pressure (IOP) measurements with Diaton and the Goldmann applanation tonometer (GAT). Methods In this cross-sectional study, 162 eyes of 81 participants were included. Intraocular pressure measurements were obtained in all patients using Diaton and GAT. Central corneal thickness was determined by ultrasound pachymetry. The participants were stratified by corneal thickness: group I <530 μm (n = 56), group II 530–560 μm (n = 65), and group III >560 μm (n = 41). Results There were moderate correlations between IOP readings obtained using the Diaton and corrected GAT (C-GAT) (r = 0.303; P < 0.0001), and between corrected Diaton (C-Diaton), and C-GAT (r = 0.399; P < 0.0001). The mean Diaton tonometer readings were lower than C-GAT measurements (Diaton-corrected GAT mean difference, 0.9 ± 3.8 mmHg; c-Diaton-corrected GAT mean difference, 0.7 ± 3.5 mmHg). Differences were detected between the groups of patients for the GAT values [2.4 ± 3.6 mmHg for those with the thinnest corneas (<530 μm), 0.7 ± 3.6 mmHg for those with moderate corneas (between 531 μm and 560 μm), and −0.6 ± 3.6 mmHg for those with the thickest (>560 μm) corneas], whereas a significantly lower difference (0.9 ± 3.8 mmHg) was noted for the Diaton values of all individuals. Conclusions The Diaton measurements show moderate correlation with those provided by applanation tonometry. The Diaton tonometer seems to be more affected by the corneal thickness, especially in the thinnest corneas. No author has a financial interest in any product mentioned in the article. No author has a conflict of interest in any product mentioned in the article.     

Corneal endothelial status in the subtypes of primary angle closure glaucoma

Purpose: To study the corneal endothelium and pachy­metry in eyes with different subtypes of primary angle closure glaucoma (PACG), as compared to controls. Methods: A cross‐sectional study was conducted on 30 consecutive patients in each subtype of PACG, subacute, acute and chronic, and 30 age and refraction matched controls. The parameters recorded included gonioscopy, optic disc evaluation, applanation tonometry, specular microscopy and central ultrasonic pachymetry. Results: The mean endothelial cell counts in the four groups were as follows: subacute PACG 2396 ± 271 cells/mm², acute PACG 1597 ± 653 cells/mm², chronic PACG 2229 ± 655 cells/mm² and controls 2461 ± 321 cells/mm². The mean endothelial cell count in the fellow eyes of subacute PACG, acute PACG and chronic PACG patients was 2294 ± 305 cells/mm², 2388 ± 226 cells/mm² and 2108 ± 203 cells/mm², respectively (NS). The acute PACG patients had significantly lower endothelial cell counts (P < 0.001) as compared to the other three groups. Eyes in which the acute attack of angle closure persisted for less than 72 h had a mean endothelial cell count of 2016 ± 306 cells/mm², as compared to 759 ± 94.4 cells/mm² in eyes with an attack lasting for 72 h or more (P < 0.001). The endothelial count was also significantly lower in eyes with chronic PACG as compared to control eyes (P < 0.001). There was increased pleomorphism and polymegathism of the corneal endothelial cells seen in eyes with resolved acute and chronic PACG. The mean central corneal thickness was 531.4 ± 25.3 µm in eyes with subacute PACG, 567.9 ± 37.3 µm in eyes with acute PACG, 526.4 ± 31.9 µm in eyes with chronic PACG and 525 ± 12.6 µm in control eyes. The acute PACG eyes had a significantly higher corneal thickness (P < 0.001) when compared to all the other groups. Conclusion: There is a significant decrease in the corneal endothelial cell density in eyes that have had an acute attack of angle closure glaucoma and in eyes with chronic PACG. The endothelial cell population in eyes with sub­acute PACG and in the fellow eyes of all subtypes of PACG is not significantly different from the normal population.     

A fish eye out of water: epithelial surface projections on aerial and aquatic corneas of the 'four-eyed fish' Anableps anableps

Background: Vertebrate corneas feature a variety of microprojections, to which a tear film adheres. These microprojections are formed by folds in epithelial cell membranes, which increase surface area, stabilise the tear film and enhance movement of nutritional and waste products across cell membranes. Differences in corneal microprojections among vertebrates have been correlated with habitat and differ markedly between terrestrial and aquatic species. Methods: This study investigated epithelial microprojections of both the aerial (dorsal) and aquatic (ventral) corneal surfaces of the ‘four‐eyed fish’Anableps anableps using scanning electron microscopy. Results: The central region of the dorsal cornea, which projects above the water, had a density of 16,387 ± 3,995 cells per mm², while the central region of the ventral cornea (underwater) had a density of 22,428 ± 6,387 cells per mm², a difference that suggests an environmental adaptation along the two visual axes. Both corneal surfaces were found to possess microridges rather than microvilli or microplicae characteristic of terrestrial/aerial vertebrates. Microridges were 142 ± 9 nm wide and did not differ (p = 0.757) between dorsal and ventral corneas. Microridges were consistently separated by a distance of 369 ± 9 nm across both corneas. Conclusion: Dorsal‐ventral differences in corneal epithelial cell density in Anableps anableps suggest a difference in osmotic pressure of the two corneas. The modest differences in the microprojections indicate that the need to secure the tear film underlying each optical axis is of prime importance, due to the likelihood that a persistent layer of water normally covers both dorsal and ventral corneal surfaces and that maintaining a transparent optical pathway for vision is critical for a species prone to predation from both above and below the water's surface.     

Clinical outcomes after Descemet’s stripping endothelial keratoplasty using donor corneas from children younger than 3 years

Importance

There is limited literature on paediatric donors in endothelial keratoplasty.

Background

This study investigated the efficacy of and appropriate paediatric donor age for Descemet’s stripping endothelial keratoplasty (DSEK).

Design

Retrospective and observational case series.

Participants

Thirty‐eight consecutive patients underwent DSEK with paediatric donor corneas.

Methods

The age of the donors ranged from 32 weeks gestation (premature neonate) to 3 years old. All donor consents were obtained from the parents. The causes of donor death included traffic accident, congenital heart disease and neonatal respiratory distress syndrome.

Main Outcome Measures

The outcome measures included best‐corrected visual acuity, endothelial cell loss and complications.

Results

Best‐corrected visual acuity at last follow‐up was >20/40 in 28 of 38 eyes (73.7%). The mean preoperative endothelial cell density of donor corneas was 4682 ± 520 cells/mm². The mean endothelial cell density of grafts was 3977 ± 556 cells/mm² at 18 months postoperatively. Three lenticules from premature neonate donors exhibited severe contraction postoperatively. The edge of six lenticules from donors <1‐year‐old exhibited contraction in the early postoperative period and gradually flattened spontaneously. Graft detachment occurred in one patient.

Conclusions and Relevance

DSEK with paediatric donor corneas can achieve good clinical outcomes. The corneal lenticules from 1‐ to 3‐year‐ old donors are suitable for DSEK while those from donors <1‐year‐old are less suitable due to the possibility of severe postoperative graft contraction.     

Tissue quality of eye-bank–prepared precut corneas for Descemet’s stripping automated endothelial keratoplasty

Objective

To evaluate endothelial cell density (ECD) of eye-bank–prepared tissue for use in Descemet’s stripping automated endothelial keratoplasty (DSAEK).

Design

Prospective case series of consecutive corneal tissue prepared for DSAEK surgery.

Participants

Sixty-seven sequential corneal-scleral tissue specimens representing 48 human donors processed for use in DSAEK surgery by the Regional Tissue Bank (Halifax, Nova Scotia).

Methods

Corneal-scleral donor tissue was obtained by in situ recovery. ECD was recorded using the EB-3000 XYZ (HAI Laboratories Inc, Lexington, MA) specular microscope within 24 hours of preservation. Before the tissue was dissected, the corneal thickness was measured using the DGH-550 PACHETTE 2 (DGH Technology, Exton, PA) ultrasound pachymeter. The dissection was performed using a 300-μm Moria ALTK model microkeratome (Moria Inc). The posterior bed thickness was measured, and the anterior flap was replaced. Endothelial cell count density was obtained after re-preservation.

Results

Complete measurements were obtained for 42 of 67 corneas. In 25 corneas it was not possible to obtain a postdissection ECD measurement. The mean ECD before dissection was 2806 ± 317 cells/mm². The mean ECD after dissection was 2772 ± 318 cells/mm². There was an average loss of 34 cells/mm² (95% CI –110 to 40 cells/mm², p = 0.3).

Conclusions

This case series confirms that ECD is preserved when DSAEK tissue is prepared in advance of surgery by trained eye-bank technicians in a low-volume Canadian eye bank. It was difficult to obtain clear images of the endothelial cell layer postdissection, possibly because of tissue swelling or distortion. Sixty-six of 67 corneas included in the study were used for surgery.     

白内障超声乳化吸除术后角膜内皮细胞变化的研究

目的:观察不同类型白内障患者超声乳化吸除术后角膜内皮细胞的变化。方法:随机选取我院老年性白内障、糖尿病性白内障及高度近视并发性白内障患者各30例30眼,均行白内障超声乳化吸除联合人工晶状体植入手术,于术前及术后1wk采用非接触型角膜内皮显微镜行角膜内皮细胞密度及六角形细胞比例检查。结果:三组术前角膜内皮细胞密度及六角形细胞比例比较,差异无统计学意义(P>0.05)。三组术后1wk角膜内皮细胞密度分别为2 496.86±298.96/mm2,2 379.51±375.13/mm2,2 425.38±312.68/mm2,六角形细胞比例分别为(46.20±12.03)%,(43.44±13.99)%,(44.35±8.13)%。三组术后1wk角膜内皮细胞密度及六角形细胞比例均较术前减少,其差异均有统计学意义(P<0.05)。术后各组间比较,糖尿病性白内障组和高度近视并发性白内障组术后均较老年性白内障组术后降低,其中糖尿病性白内障组术后角膜内皮细胞密度和六角形细胞比例降低较明显,与老年性白内障组比较,其差异有统计学意义(P<0.05)。结论:糖尿病性白内障及高度近视并发性白内障患者角膜内皮对超声乳化手术的耐受性降低,对角膜内皮细胞应行准确术前评估及术中保护。     

Evaluation of various preservation media for storage of donor corneas

Purpose:To compare the physical and microbiological characteristics of McCarey-Kaufman (MK), Cornisol, and Optisol-GS media and evaluate the outcomes of keratoplasty performed using corneas stored in these three media.Methods:The study involved 60 donor corneas which were distributed in 3 groups: MK, Cornisol, and Optisol-GS. Corneas in these groups were further analyzed based on the type of keratoplasty performed (full thickness versus endothelial keratoplasty). At baseline, the endothelial cell density and death to preservation time of donor corneas were recorded. Following keratoplasty, patients were evaluated on day 1, at 1 month, 3 months, and 6 months follow-up. Outcomes were assessed in terms of corrected distance visual acuity (CDVA), endothelial cell density, percentage endothelial cell loss, and corneal thickness. The storage media were also assessed for their physical quality and their microbiological characteristics.Results:Physical characteristics of all three media were found to be within normal limits. Mean CDVA was comparable among the 3 groups at 6-month follow-up. The absolute endothelial cell count values were significantly lower for corneas stored in MK medium (1873.7 ± 261.1 cells/mm²) compared to the Cornisol (2085.0 ± 230.3 cells/mm²) and Optisol-GS media [(2180.3 ± 217.2 cells/mm²) (P = <0.001)]. Corneas stored in Optisol-GS medium were significantly thinner at 1-month follow-up with no significant difference at 6 months (P = 0.66).Conclusion:Optisol-GS and Cornisol media were found to preserve endothelial cell density better and stabilize corneal thickness earlier as compared to the MK medium. However, the functional outcomes were comparable among the three groups.     

Endothelial cell survival on transplanted human corneas preserved by organ culture with 1.35% chondroitin sulfate

We transplanted 30 donor corneas preserved at 34 C for 15 to 33 days in culture medium containing 1.35% chondroitin sulfate and compared them with 30 corneas transplanted during the same period, but preserved only in McCarey-Kaufman medium at 4 C for one to 81 hours. Two months after keratoplasty there was no statistically significant difference in central endothelial cell loss between the organ-cultured grafts and those preserved in McCarey-Kaufman medium (9% vs 7% cell loss, respectively). The study detected with 90% power a difference in cell loss of approximately 10% or more. On the first postoperative day, the organ-cultured grafts were thicker than those grafts preserved in McCarey-Kaufman medium, and the thickest corneas were those cultured for the longest times. The corneal thickness was similar in the two groups after three weeks. These results demonstrated that donor corneal endothelial cells preserved for up to one month at 34 C in 1.35% chondroitin sulfate appear to survive and function after keratoplasty as well as those preserved at 4 C for one to three days in McCarey-Kaufman medium.     

Corneal endothelial cell density and morphology and central corneal thickness in Guangxi Maonan and Han adolescent students of China

AIM:To investigate the corneal endothelial cell density and morphology and central corneal thickness in the Guangxi Maonan and Han adolescent students of China.METHODS:Noncontact specular microscope (Topcon SP3000P, Tokyo, Japan) was performed in 133 adolescent students of Maonan nationality (M:F 54:79) and 105 adolescent students of Han nationality (M:F 50:55), 5 to 20y of age, who were randomly selected from 3 schools in Huanjiang Maonan Autonomous County of Guangxi Zhuang Autonomous Region of China. Parameters studied included endothelial cell density, mean cell area, coefficient of variation in cell size, percentage hexagonality and central corneal thickness.RESULTS:Endothelial cell density, mean cell area, coefficient of variation in cell size, percentage hexagonality and central corneal thickness in the study population were (2969.50±253.93) cells/mm², (339.23±29.44) μm², (29.96±4.07) %, (64.58±9.41) % and (523.71±32.82) μm in Maonan and (2998.26±262.65) cells/mm², (336.11±30.07) μm², (29.89±5.03) %, (64.91±11.64) % and (524.39±33.15) μm in Han, respectively. No significant differences were observed in endothelial cell density, mean cell area, coefficient of variation in cell size, percentage hexagonality and central corneal thickness between Maonan and Han (P=0.615, 0.659, 0.528, 0.551, 0.999). In Maonan and Han, we found age was negatively correlated with endothelial cell density and percentage hexagonality and positively correlated with mean cell area and coefficient of variation in cell size. Negative correlation was also found between central corneal thickness and age in Han, whereas no correlation was found in Maonan.CONCLUSION:There were no differences between Maonan and Han in corneal endothelial cell density and morphology and central corneal thickness. In these two nationalities, there were statistically significant decrease in endothelial cell density and percentage hexagonality with increasing age and statistically significant increase in cell area and coefficient of variation in cell size with increasing age. Central corneal thinned with increasing age in Han, whereas difference did not attain statistical significance in Maonan.