Residual Stroma Research Articles

Stromal alteration in post‐lasik ectasia cornea

AbstractPurpose Post‐LASIK corneal ectasia is a serious late postoperative complication. After LASIK, the corneal stroma is structurally weakened. Patients with this complication present with an increase in myopia and astigmatism. Here we report the stromal alteration in the post‐LASIK cornea.Methods Two Saudi male patients were diagnosed post‐LASIK ectasia. Patient 1, had ectasia six years after LASIK in both eyes. Patient 2, had ectasia four years after LASIK in right eye. Both patients had undergone penetrating keratoplasty in the right eye. The corneas were processed for light (LM) and electron microscopy (EM).Results The LASIK flap was detached from the residual stromal bed. The posterior end of the flap which had separated from the stromal bed lacked collagen fibrils and instead contained numerous very fine microfilaments. The proteoglycans were absent. There were large keratocytes containing a large nucleus in the stroma. The stromal lamellae were thin and disorganized. The collagen fibrils were running randomly and their distribution was not uniform. There were aggregates of micro‐filaments, which replaced some parts of the Bowman’s layer and stroma.Conclusion The present study showed the disorganisation of the lamellae collagen fibrils. A large number of microfilaments were present at the detachment end of the flap and the residual stroma. Numerous aggregates of micro‐fibrils replaced some parts of the Bowman’s layer and stroma. Acknowledgement: Supported by National Plan for Science and Technology, KSU, Riyadh.

Comparison of Pneumatic Dissection and Forceps Dissection in Descemet Membrane Endothelial Keratoplasty

To compare air and forceps dissection of Descemet membrane (DM) in regard to endothelial cell loss, apoptosis, and ultrastructural findings for transplantation in Descemet membrane endothelial keratoplasty. DM of 32 corneoscleral rims were separated using forceps dissection (group A) and air dissection (group B) and had been organ cultured for 1 week. The endothelial cell density (ECD) was evaluated before and immediately after DM dissection and during 1 additional week of organ culture. The presence of any residual stroma, thickness of the DM, thickness of banded and nonbanded layers, and smoothness of the lamella were analyzed. Apoptosis was evaluated by TUNEL (terminal dUTP nick-end-labeling) staining. In group A, 15 of 16 usable DM were available, and in group B 14 of 16 usable DM were available. The duration of preparation was 19.7 minutes in group A and 8.8 minutes in group B. The mean ECD was 2050 ± 167 cells per square millimeter in group A and declined to 1846 ± 153 cells per square millimeter after 1 week of organ culture. The mean ECD in group B was 2038 ± 212 cells per square millimeter and declined to 1863 ± 211 cells per square millimeter. No evidence of adherent rests of corneal stroma in any specimens in either group was observed, demonstrating a stroma free separation with no differences in the smoothness of the lamellae. The rate of apoptosis positive cells was 0.37% in group A and 0.40% in group B. Both separation methods seem to be equal in regard to the quality of the obtained DM. Finally, it depends on the preference of the surgeon which dissection method to use.

Donor Preparation Using Pneumatic Dissection in Endothelial Keratoplasty

To determine if residual stroma remains on the Descemet membrane when pneumatic dissection is used to prepare donor tissue for endothelial keratoplasty. Pneumatic dissection using a posterior peripheral needle insertion was carried out on 5 eye bank corneas. Samples were then sent for histological analysis. A thin layer of stroma remained on the Descemet membrane in all the samples. The average central stromal thickness was 12.4 μm (range 6.5-20.0 μm). Endothelial keratoplasty using pneumatic dissection to prepare donor tissue should be considered a form of Descemet stripping endothelial keratoplasty and not Descemet membrane endothelial keratoplasty. If future studies show excellent visual results using pneumatic dissection for endothelial keratoplasty, then removal of all donor stroma may be unnecessary.

Histologische und ultrastrukturelle Untersuchung der Descemet-Membran nach Descemetorhexis bei der DMEK- Operation

In order to obtain an optimal visual outcome in the isolated transplantation of Descemet's membrane (DM) with the endothelial cell layer, a regular interface between the receiver cornea and the graft is important for the prognosis. The purpose of this histological and ultrastructural study was to investigate how precise the descemetorhexis works using the Sinskey hook and whether the precision of DM removal depends on the clinical and pathological diagnosis of the underlying corneal endothelial disease. 22 DM specimens of 22 patients obtained after descemetorhexis in DMEK using a Sinskey hook were examined using histological analyses and transmission electron microscopy for the presence of residual stroma, thickness of the DM, endothelial cell count, and presence of guttae. 17 patients had a Fuchs corneal dystrophy, 5 pseudophakic bullous keratopathy. Light and electron microscopy showed no evidence of adherent stroma in all 22 specimes after descemetorhexis independent of the different underlying endothelial pathological abnormalities. The mean total thickness of the DM was 20.58 ± 4.23 µm in patients with Fuchs endothelial dystrophy and 21.31 ± 5.41 µm in patients with bullous keratopathy. There was no significant difference between both pathological abnormalities. The anterior banded layer measured a mean of 3.04 ± 0.40 µm and 3.25 ± 0.22 µm thick; the posterior non-banded layer 17. 63 ± 4.07 µm and 17.60 ± 5.0 µm thick in each case of Fuchs corneal dystrophy and pseudophakic bullous keratopathy. There was no significant difference between the two diseases. Descemetorhexis allows a selective removal of the DM without adherent stroma in different underlying endothelial pathological abnormalities and in different variability of disease expression.

Ring-shaped corneoscleral lamellar keratoplasty guided by high-definition optical coherence tomography and Scheimpflug imaging for severe Terrien’s marginal corneal degeneration

To evaluate the clinical efficacy of ring-shaped corneoscleral lamellar keratoplasty under guidance of high-definition optical coherence tomography (HD-OCT) and Scheimpflug imaging for severe Terrien's marginal corneal degeneration. Twenty-five patients (25 eyes) with Terrien's marginal corneal degeneration and ≥ 6 diopters of astigmatism were treated at the Shandong Eye Institute from January 2008 through December 2010. In these patients, the diseased area was > 1 quarter of the cornea, and the thickness at the thinnest corneal area was < 150 μm with residual corneal stroma. Ring-shaped corneoscleral lamellar keratoplasty was performed, and the depth and width of dissection was set according to the HD-OCT and Pentacam examinations. Data of complications, surgical effects, visual acuity, and astigmatism were collected. No intraoperative corneal perforation occurred. No patients had liquid accumulation between the graft and the recipient. At 1 year after surgery, the average best-corrected visual acuity improved to 6/9 from preoperative 6/36, and the average astigmatism reduced to 4.37 (2.04) diopters from preoperative 13.39 (7.52) diopters. There was no recurrence of the disease or corneal graft rejection in the follow-up period. Ring-shaped corneoscleral lamellar keratoplasty guided by HD-OCT and Pentacam imaging appears to be effective in the treatment of severe Terrien's marginal corneal degeneration. Surgical perforation can be significantly reduced.

Deep anterior lamellar keratoplasty for pellucid marginal degeneration

PurposeTo present the surgical outcomes of deep anterior lamellar keratoplasty (DALK) for pellucid marginal degeneration (PMD). MethodsA retrospective review was performed in 16 eyes of 16 patients who underwent DALK at the King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia between January 1, 2006 and December 30, 2009. Baring of Descemet’s membrane (DM) during DALK was achieved in 8 (50%) eyes; residual stroma was left intraoperatively in the remaining 8 (50%) eyes. The big bubble technique was performed in 10 (62.5%) eyes and manual dissection was performed in the remaining 6 (37.5%) eyes. Visual acuity (LogMAR notation), intraocular pressure, intraoperative complications and postoperative graft status were assessed. ResultsThe mean follow up was 14.6±8.2months (range 6–35months). The mean overall age was 31.4±9.6years (range, 19–50years). Visual acuity increased statistically significantly from 0.9±0.3 (range 0.5–1.6) preoperatively to 0.4±0.2 (range 0.0–0.7) at last follow-up (p<0.0001). There was a statistically significant improvement in postoperative sphere, cylinder, and spherical equivalent (p<0.035, p<0.001, and p<0.02, respectively) compared to preoperative. Postoperative visual acuity was not statistically significantly related to gender, type of surgical technique, and baring or perforation of DM. The main graft-related complication was graft–host vascularization (2/16 eyes). ConclusionDALK reduces severe corneal astigmatism and results in good visual and refractive outcomes and is an effective alternative for patients with PMD.

Patterns of Pathomorphological Changes in Acute Necrotizing Pancreatitis

Acinar necrosis is the basic microscopic sign of acute necrotizing pancreatitis (ANP). Microcirculation disorder is one of the major factors in the pathogenesis and morphogenesis of ANP besides free radicals and damage of enzymatic origin. This study is dedicated to the description of microscopic changes in the pancreatic stroma in ANP, which leads to destruction of the exocrine pancreas with a putative mechanism of endocrine function preservation. This study has been carried out on histological samples of pancreas from 224 patients with ANP. Histological staining was performed with hematoxylin-eosin (H&E), Masson, Gomori methods, and PAS. Microscopy was performed with magnifications of 40×, 100×, and 400×. Vascular endothelial desquamation, stasis, and sludge are typical changes in microcirculation observed in early stages of ANP. Initially, parietal circular intravascular microthrombosis accompanied by endothelial desquamation as early as stromal swelling occurs with no detectable necrosis. Residual stroma appears between areas of necrosis and intact pancreatic tissue. Mucoid swelling is first seen in the perivascular spaces extending to the parenchyma and changing into fibrinoid imbibition causing further necrosis. Reticulin argyrophilic backbone surrounding the pancreatic acini and small ducts decompose. Pancreatic structures, which may be preserved in necrotic tissue, include nerves, major ducts, and Langerhans islets.

Long-term Results of Deep Anterior Lamellar versus Penetrating Keratoplasty

To compare deep anterior lamellar keratoplasty (DALK) with penetrating keratoplasty (PK) in eyes with corneal diseases not involving the corneal endothelium (keratoconus, scars after infectious keratitis, stromal dystrophies, and trauma). Retrospective, comparative case series. One hundred forty-two consecutive DALK (DALK group; big-bubble technique or manual lamellar dissection using a slitlamp) and 142 matched PK (PK group). Three models were used to describe the postoperative outcomes of the endothelial cell density. A joint regression model was used to predict long-term graft survival. Visual acuity, ultrasound pachymetry, specular microscopy, and optical coherence tomography (OCT) findings were recorded. Postoperative endothelial cell loss and long-term predicted graft survival. The average 5-year postoperative endothelial cell loss was -22.3% in the DALK group and -50.1% in the PK group (P<0.0001). The early- and late-phase annual rates of endothelial cell loss were -8.3% and -3.9% per year, respectively, in the DALK group and -15.2% and -7.8% per year in the PK group (P<0.001; biphasic linear model). The median predicted graft survival was 49.0 years in the DALK group and 17.3 years in the PK group (P<0.0001). The average visual acuity was lower in the manual dissection subgroup compared with the PK group (average difference, 1.0 to 1.8 line) and with the big-bubble subgroup (average difference, 2.2 to 2.5 lines). The average central corneal thickness at 12 months was 536 μm in the PK group, 523 μm in the big-bubble subgroup, and 562 μm in the manual dissection subgroup (P<0.001). The average thickness of the residual recipient stroma measured by OCT was 87±26 μm in the manual dissection subgroup. No correlation was found between this figure and logarithm of the minimal angle of resolution at any postoperative time point (P>0.05). Long-term, model-predicted graft survival and endothelial densities are higher after DALK than after PK. The big-bubble technique gives better results than manual dissection and PK. Compared with PK, manual dissection provides higher survival of both the corneal endothelium and graft, but lower visual acuity.

Residual corneal stroma in big-bubble deep anterior lamellar keratoplasty: a histological study in eye-bank corneas

AimTo determine if residual corneal stroma remains on the recipient posterior lamella in big-bubble deep anterior lamellar keratoplasty (DALK).MethodsPneumodissection using the big-bubble technique was carried out on eye-bank corneas mounted...

Cancer-associated fibroblasts correlate with poor prognosis in rectal cancer after chemoradiotherapy

Cancer-associated fibroblasts (CAFs) in the stroma play an important role in influencing the proliferation, invasion and metastasis of cancer cells. Fibroblast activation protein-α (FAP-α) is known as a marker of CAFs, while stromal cell-derived factor-1 (SDF-1) is primarily expressed by CAFs. Herein, we investigated whether the expression levels of these genes are associated with clinical outcome after pre-operative chemoradiotherapy (CRT) in rectal cancer patients. We obtained total RNA from residual cancer stroma using microdissection from a total of 52 rectal cancer specimens from patients who underwent pre-operative CRT, we performed transcriptional analyses, and the serum protein concentrations in 40 matched microdissected specimens were measured by enzyme-linked immunosorbent assay. Additionally, we sought to clarify the location of FAP-α and SDF-1 expression using immunohistochemical staining. Of the 52 patients, 15.6 and 36.8% showed detectable FAP-α and SDF-1 mRNA expression, respectively. A significant correlation was observed between stromal FAP-α and SDF-1 mRNA levels. Moreover, there was a significant correlation between stromal SDF-1 gene expression levels and serum protein levels. Patients who developed distant recurrences after CRT had positive expression of both genes (P<0.05). The positive expression of both genes was also associated with poor probability of recurrence-free and overall survival (P<0.05). Patients with elevated serum SDF-1 levels had equally poor overall survival as those with positive stromal SDF-1 gene expression (P<0.05). In immunohistochemistry, both FAP-α and SDF-1 expression was observed in certain activated fibroblasts. In conclusion, FAP-α and SDF-1 expression was shown to be involved in tumor re-growth and recurrence in rectal cancer patients treated with pre-operative CRT.

A Surgical Technique for Donor Tissue Harvesting for Descemet Membrane Endothelial Keratoplasty

To create a reproducible and effective technique in donor tissue harvesting for Descemet membrane (DM) endothelial keratoplasty. A new method has been developed for the harvest of donor DM and endothelium. This method involves placement of a human corneoscleral rim in an artificial anterior chamber with removal of the anterior stroma with a Moria One microkeratome (Moria USA, Doylestown, PA). The residual stromal bed over the central cornea is removed by blunt dissection using a Barraquer sweep. A thin rim of posterior residual stroma permits easy donor button trephination and tissue manipulation. The risk of tearing through DM is minimal and may not preclude use in transplantation. This method allows relatively easy assessment of endothelial integrity before trephination. Optical coherence tomography evaluation revealed minimal stroma overlying DM and endothelium. Endothelial cell integrity of the harvested DM by this new harvest method was assessed using specular microscopy and demonstrated minimal loss after DM harvest. We presented a manual tissue harvest method for DM endothelial keratoplasty.

Common complications of deep lamellar keratoplasty in the early phase of the learning curve

Purpose:To evaluate and record the common complications that face surgeons when they perform their first few series of deep lamellar keratoplasty and measures to avoid these.Setting:Dar El Oyoun Hospital, Cairo, Egypt.Methods:Retrospective study of the first 40 eyes of 40 patients carried out by two corneal surgeons working in the same center. All patients were planned to undergo a deep anterior lamellar keratoplasty using the big bubble technique. Twelve patients suffered from keratoconus while 28 patients had anterior corneal pathologies. Recorded complications were classified as either intraoperative or postoperative.Results:Perforation of Descemet’s membrane was the most common intraoperative complication. It occurred in nine eyes (22.5%): five eyes (12.5%) had microperforations while four eyes (10%) had macroperforations, three eyes (7.5%) had central perforations, and six eyes (15%) had peripheral perforations. Other complications included incomplete separation of Descemet’s membrane and remnants of peripheral stromal tissue. Postoperative complications included double anterior chamber which occurred in four eyes (10%) and Descemet’s membrane corrugations. Postoperative astigmatism ranged from 1.25 to 4.5 diopters with a mean of 2.86 diopters in the whole series, but in the six cases with identified residual stroma in the periphery of the host bed, the astigmatism ranged from 2.75 to 4.5 diopters with a mean of 3.62 diopters.Conclusion:Deep lamellar keratoplasty is sensitive to procedural details. Learning the common complications and how to avoid them helps novice surgeons to learn the procedure faster.

Refractive Outcome of Keratoconus Treated by Combined Femtosecond Laser and Big-Bubble Deep Anterior Lamellar Keratoplasty

To report 1-year follow-up in 11 of 13 eyes with keratoconus treated by deep anterior lamellar keratoplasty with a combined femtosecond laser lamellar resection followed by a big-bubble dissection. Thirteen eyes with keratoconus were treated. Recipient and donor were prepared with the 60-kHz IntraLase femtosecond laser (Abbott Medical Optics). In the recipient, the femtosecond laser, after performing a lamellar cut 100 μm above the thinnest corneal point (measured by Pentacam [Oculus Optikgeräte GmbH]), was used to make a mushroom-shaped resection (anterior diameter, 9 mm; posterior diameter, 8 mm) from the same depth. In the donor, the mushroom lamellar thickness was calculated according to an original model based on the recipient preoperative corneal thickness. Upon removal of the recipient lamella, air was injected into the residual stroma to achieve a big bubble. The keratectomy was continued up to Descemet membrane. The donor was fit into place and sutured using interrupted sutures, which were removed by 8 months postoperative. Corrected distance visual acuity (CDVA) and refractive astigmatism were calculated by manifest refraction, whereas topographic astigmatism and corneal thickness were measured by Pentacam. A big bubble was successfully achieved in 11 eyes. Twelve months after surgery, mean CDVA was 0.52±1.2 (decimal), and refractive sphere and cylinder were -1.50±1.70 diopters (D) and 2.00±2.60 D, respectively. Three (27%) of 11 eyes at 1 year had a manifest refraction spherical equivalent within 1.00 D of emmetropia. Topographic astigmatism was 2.90±1.60 D. The thinnest corneal point was 519±27 μm. This combination of a femtosecond laser lamellar dissection with a big-bubble technique can improve the standardization of deep anterior lamellar keratoplasty for keratoconus.

Control of Femtosecond Thin-flap LASIK Using OCT in Human Donor Eyes

Thin-flap keratomileusis is a procedure that minimizes LASIK flap thickness to preserve both the corneal epithelium and the maximum residual stroma. This study investigated the usefulness of optical coherence tomography (OCT) as a tool in guiding the femtosecond laser in the creation of a thin flap in human eyes in a non-randomized case series. In a private research laboratory, an in vitro investigation was performed on human autopsy eyes. Five human cadaver eyes, unsuitable for transplantation, underwent flap creation with a femtosecond laser. The laser procedure was controlled in real-time with an OCT system (Thorlabs HL AG) to ensure that the cut was placed just underneath Bowman's layer. The repetition rate of the femtosecond laser was 10 MHz with a single-pulse duration of <400 femtoseconds (pulse energy in the nJ range). As a control, all eyes underwent histological dissection and were examined using light microscopy. Video monitoring of the flap creation supported the feasibility of real-time OCT monitoring of the femtosecond laser flap creation process. A clear distinction of the corneal epithelium was possible in all eyes. Bowman's layer was not identified in all donor eyes at the given resolution of the OCT device used in this study. Light microscopy demonstrated flaps approximately 50-microm thick, confirming that the real-time monitoring assured a positioning of the cutting plane at minimum distance underneath Bowman's layer. This study of five human cadaver eyes shows that real-time OCT monitoring of the creation of thin-flaps in LASIK using a femtosecond laser is possible, thus ensuring that the flap is created at the desired depth.

Comparative Evaluation of Big-Bubble Deep Anterior Lamellar Keratoplasty and Penetrating Keratoplasty in a Case of Macular Corneal Dystrophy

A case of a 54-year-old patient with macular corneal dystrophy who underwent a penetrating keratoplasty (PK) in the left eye and a deep anterior lamellar keratoplasty (DALK) in the right eye is described. The merits of PK versus DALK for visual rehabilitation in macular corneal dystrophy are discussed. After deep lamellar dissection in the left eye, the remaining bed of residual stroma, Descemet membrane, and endothelium was unacceptably hazy and thus converted to PK. The right eye had successful DALK because a relatively clear bed was noted after deep lamellar separation using the big-bubble technique. The spectacle-corrected visual acuities at 2-year follow-up are 6/6 OD and 6/9+ OS. There is mild residual haze in the right eye, although the visual acuity is better in this eye. Endothelial cell counts were satisfactory and not significantly different in both eyes. This case demonstrates that DALK with the big-bubble technique can be successfully carried out for visual rehabilitation in macular dystrophy. DALK should be considered in cases with no significant Descemet membrane and endothelial involvement because of the potential advantages offered by retaining the host endothelium.

Traumatic Graft Dehiscence After Anterior Lamellar Keratoplasty

A 64-year-old man underwent anterior lamellar keratoplasty using the Melles technique for corneal scar secondary to healed bacterial keratitis in the left eye. Two months postoperatively, the patient presented with blurry vision in the left eye after a fall in the bathroom. The uncorrected visual acuity was 20/400 in the left eye, and the external examination showed periorbital swelling with ecchymosis. Slit-lamp examination revealed an absent graft, a circular crater in the center, and a fragment of suture on the temporal edge of the crater. The Seidel test was negative, and there was no sign of infection. The anterior segment optical coherence tomography showed intact residual stroma with slight forward protrusion. The patient underwent repeat anterior lamellar corneal transplantation with improvement in uncorrected visual acuity of 20/100 and best spectacle-corrected visual acuity of 20/70 in the left eye 3 months postoperatively.

Effect of intraoperative mitomycin-C on healthy corneal endothelium after laser-assisted subepithelial keratectomy

To evaluate the effect of mitomycin-C (MMC) on corneal endothelial cells after laser-assisted subepithelial keratectomy (LASEK). Department of Ophthalmology, Changzheng Hospital, Shanghai, China. One hundred seventy-four eyes of 89 patients who did not previously wear contact lenses were treated with LASEK with intraoperative use of topical MMC 0.02% (15 seconds). Noncontact corneal specular microscopy was performed in all eyes preoperatively and 1, 3, and 6 months after surgery. Preoperative pachymetry and ablation depth were measured in all eyes. Repeated-measures analysis of variance was used to compare the changes in the endothelial central cell density (CCD), coefficient of variation in cell size (CV), and percentage of hexagram cells (HEX) over time. Linear regression analysis was conducted to analyze the correlation between the change in the 3 corneal endothelium indices over time and the ablation depth and residual stroma bed (RSB) thickness. Preoperatively, the mean CCD was 2755 cells/mm(2)+/-373 (SD), the mean CV was 31.45+/-8.26, and the mean HEX was 66.03%+/-25.83%. After LASEK, there were no statistically significant changes in CCD, CV, or HEX (P>.05). Multiple linear regression did not identify ablation depth or RSB thickness as being predictive of a change in CCD, CV, or HEX (P>.05). The use of intraoperative topical MMC 0.02% for 15 seconds after LASEK did not affect the corneal endothelium.

Use of trypan blue dye during conversion of deep anterior lamellar keratoplasty to penetrating keratoplasty

We describe a technique that uses trypan blue dye to identify residual recipient corneal stroma and Descemet membrane (DM) during conversion of deep anterior lamellar keratoplasty (DALK) to penetrating keratoplasty (PKP). After the host cornea is dissected, trypan blue dye (0.06%) is used to highlight the remaining host corneal stroma and DM, if any. In 8 DALK procedures that had to be converted to PKP because of DM perforation, trypan blue staining identified remnants of DM and parts of the posterior corneal stroma in 7 eyes. Improved visualization of the residual host tissue enabled complete excision and an overall optimal recipient wound profile.

Histologic Analysis of Descemet Stripping in Posterior Lamellar Keratoplasty

To investigate how precise Descemet stripping works in posterior lamellar keratoplasty (Descemet stripping automated endothelial keratoplasty [DSAEK]) for the treatment of corneal endothelial disorders. In a prospective, single-center, nonrandomized consecutive series, 20 Descemet membrane specimens obtained after Descemet stripping in DSAEK using a Price hook were examined using histologic analysis and transmission electron microscopy for the presence of residual stroma, thickness of the Descemet membrane, endothelial cell count, and presence of guttae or a posterior collagenous layer. Pathologic findings were correlated with the underlying clinical disease. Light and electron microscopy revealed no evidence of adherent rests of corneal stroma in all 20 specimens after Descemet stripping. The mean (SD) total thickness of the Descemet membrane was 21.5 (4.5) microm in peripheral localization and 17.6 (3.8) microm in central localization. The anterior banded layer measured a mean (SD) of 3.0 (0.8) microm thick; the posterior nonbanded layer, 16.7 (5.2) microm thick. The mean (SD) endothelial cell count was 1.7 (1.4) cells per high-power field. Guttae were seen in 15 specimens (75%), and a posterior collagenous layer was found in 3 (15%). Descemet stripping in DSAEK using the Price hook achieves complete and specific removal of the Descemet membrane without adherent stroma in different underlying endothelial pathologic abnormalities.

Air-Guided Manual Deep Anterior Lamellar Keratoplasty: Long-Term Results and Confocal Microscopic Findings

To evaluate the long-term results of air-guided manual deep anterior lamellar keratoplasty (DALK) and to perform confocal microscopy on postoperative DALK corneas. Seven postoperative consecutive DALK corneas were evaluated 1 year after suture removal. All patients underwent a complete ophthalmologic examination evaluating visual acuity, astigmatism, corneal thickness, and endothelial cell count. Confocal microscopy was performed to examine the corneas of the seven eyes and to obtain the measured interface depth. Eighteen months after surgery, the mean postoperative uncorrected visual acuity was 20/38 and the mean best-corrected visual acuity was 20/23. Postoperative mean value of residual recipient stroma thickness was 65.57 microm +/- 28.74. Maximum depth DALK can lead to significant advantages for quality of vision when compared to other types of anterior lamellar keratoplasty. Still, it remains a challenging procedure. These results show that a deep dissection without baring Descemet membrane makes good visual results possible, preventing corneal perforation and conversion to penetrating graft.