Textural interface opacity after Descemet-stripping automated endothelial keratoplasty

Late Spontaneous Reabsorption of Interface Fluid after Descemet's Stripping Automated Endothelial Keratoplasty Surgery

An 80-year-old male was referred to our hospital for chronic bullous keratopathy in the right eye. Ten years before, he was affected by an attack of primary acute angle closure glaucoma in high hyperopia and Fuchs' endothelial dystrophy. A bilateral iridotomy was performed. Thereafter, the patient developed an endothelial decompensation in the left eye, and, in another hospital, he underwent an open-sky combined cataract extraction and penetrating keratoplasty. Our surgical approach for the right eye consisted of phacoemulsification and, after 1 month, a Descemet's stripping automated endothelial keratoplasty (DSAEK). After the procedure, an interface fluid was suspected, and an anterior segment optical coherence tomography (OCT) confirmed it. The graft was well centered but thickened, showing no movement in the anterior chamber, adherent to the periphery of the recipient cornea but with a pool of fluid in the center. Seven days postoperatively, an anterior segment OCT showed initial signs of reabsorption of the fluid. On day 45, the graft was adherent with normal thickness and the interface fluid had completely disappeared. The corneal stroma was clear, but a faint interface opacity appeared and is still present. We obtained a good surgical result and best corrected visual acuity was 7/10 at postoperative month 4. No further surgical procedures are scheduled.

Surgical management of post-Descemet stripping automated endothelial keratoplasty interface haze associated with interface deposits

We describe an effective technique for the management of graft–host interface haze associated with interface deposits after Descemet-stripping automated endothelial keratoplasty (DSAEK) with bimanual irrigation/aspiration. A Tan marginal dissector was used to separate the graft from the stroma in the nasal two-thirds of the graft–host interface. The aspiration handpiece was inserted in the interface through the nasal side-port corneal incision and a separate irrigation tip was placed in the anterior chamber (AC) through the temporal corneal paracentesis. Meticulous rinsing of the two-thirds of the interface area and the AC was performed. At the end of the procedure, air was injected into the AC to float the donor graft against the host stromal bed and facilitate graft adherence. Postoperative anterior segment optical coherence tomography and slit-lamp examination confirmed elimination of the interface haze–deposits and a well-attached graft. An improvement in visual acuity was noted.

The Corneal Basement Membranes and Stromal Fibrosis

Purpose

The purpose of this review was to provide detailed insights into the pathophysiology of myofibroblast-mediated fibrosis (scarring or late haze) after corneal injury, surgery, or infection.

Method

Literature review.

Results

The epithelium and epithelial basement membrane (EBM) and/or endothelium and Descemet's basement membrane (BM) are commonly disrupted after corneal injuries, surgeries, and infections. Regeneration of these critical regulatory structures relies on the coordinated production of BM components, including laminins, nidogens, perlecan, and collagen type IV by epithelial, endothelial, and keratocyte cells. Whether a cornea, or an area in the cornea, heals with transparency or fibrosis may be determined by whether there is injury to one or both corneal basement membranes (EBM and/or Descemet's BM) and delayed or defective regeneration or replacement of the BM. These opaque myofibroblasts, and the disordered extracellular matrix these cells produce, persist in the stroma until the EBM and/or Descemet's BM is regenerated or replaced.

Conclusions

Corneal stromal fibrosis (also termed "stromal scarring" or "late haze") occurs as a consequence of BM injury and defective regeneration in both the anterior (EBM) and posterior (Descemet's BM) cornea. The resolution of fibrosis and return of stromal transparency depends on reestablished BM structure and function. It is hypothesized that defective regeneration of the EBM or Descemet's BM allows key profibrotic growth factors, including transforming growth factor beta-1 (TGF-β1) and TGF-β2, to penetrate the stroma at sustained levels necessary to drive the development and maintenance of mature opacity-producing myofibroblasts from myofibroblast precursors cells, and studies suggest that perlecan and collagen type IV are the critical components in EBM and Descemet's BM that bind TGF-β1, TGF-β2, platelet-derived growth factor, and possibly other growth factors, and regulate their bioavailability and function during homeostasis and corneal wound healing.

Descemet stripping automated endothelial keratoplasty

Endothelial keratoplasty is at present the gold standard for surgical treatment of corneal endothelial pathologies not associated with significant corneal scar. Tremendous progress has been made in recent years in improving the technology of endothelial keratoplasty techniques, such as descemet stripping automated endothelial keratoplasty (DSAEK) and descemet membrane endothelial keratoplasty. In this review, we discuss the current techniques and outcomes of DSAEK.

'Blue bubble' technique: an ab interno approach for Descemet separation in deep anterior lamellar keratoplasty using trypan blue stained viscoelastic device

BACKGROUND

In this study, we examined a novel variant of 'big-bubble' deep anterior lamellar keratoplasty using trypan-blue-stained viscoelastic device for the creation of a pre-descemetic bubble.

METHODS

Ten corneoscleral rims were mounted on an artificial anterior chamber (AC). The AC was filled with air through a limbal paracentesis. A Melles' triangulated spatula was inserted through the paracentesis, with its tip penetrating the AC, was then slightly retracted and pushed into the deep stroma above the roof of the paracentesis. A mixture of trypan blue and viscoelastic device (Healon, Abbott Medical Optics, Abbott Park, Illinois) was injected into this intra-stromal pocket using a 27-G cannula to create a pre-descemetic separation bubble. Bubble type and visualization of dyed viscoelastic device were noted. The method was later employed in three cases.

RESULTS

In all 10 corneoscleral rims, the technique successfully created a visible pre-descemetic (type 1) bubble that could be expanded up to the predicted diameter of trephination. Subsequent trephination and the removal of corneal stroma were uneventful. In two out of four clinical cases, a type 1 bubble was created, while in two others, visco-dissection failed and dyed viscoelastic was seen in the AC.

CONCLUSIONS

The presented technique holds promise of being a relatively easy to perform, predictable and well-controlled alternative for achieving a type 1 bubble during deep anterior lamellar keratoplasty surgery. The trypan-blue-stained viscoelastic device facilitates proper visualization and control of the separation bubble and assists in identifying the penetrance to the separation bubble prior to removal of the stromal cap.

Epithelial basement membrane injury and regeneration modulates corneal fibrosis after pseudomonas corneal ulcers in rabbits

The purpose of this study was to investigate whether myofibroblast-related fibrosis (scarring) after microbial keratitis was modulated by the epithelial basement membrane (EBM) injury and regeneration. Rabbits were infected with Pseudomonas aeruginosa after epithelial scrape injury and the resultant severe keratitis was treated with topical tobramycin. Corneas were analyzed from one to four months after keratitis with slit lamp photos, immunohistochemistry for alpha-smooth muscle actin (α-SMA) and monocyte lineage marker CD11b, and transmission electron microscopy. At one month after keratitis, corneas had no detectible EBM lamina lucida or lamina densa, and the central stroma was packed with myofibroblasts that in some eyes extended to the posterior corneal surface with damage to Descemet's membrane and the endothelium. At one month, a nest of stromal cells in the midst of the SMA + myofibroblasts in the stroma that were CD11b+ may be fibrocyte precursors to myofibroblasts. At two to four months after keratitis, the EBM fully-regenerated and myofibroblasts disappeared from the anterior 60-90% of the stroma of all corneas, except for one four-month post-keratitis cornea where anterior myofibroblasts were still present in one localized pocket in the cornea. The organization of the stromal extracellular matrix also became less disorganized from two to four months after keratitis but remained abnormal compared to controls at the last time point. Myofibroblasts persisted in the posterior 10%-20% of posterior stroma even at four months after keratitis in the central cornea where Descemet's membrane and the endothelium were damaged. This study suggests that the EBM has a critical role in modulating myofibroblast development and fibrosis after keratitis-similar to the role of EBM in fibrosis after photorefractive keratectomy. Damage to EBM likely allows epithelium-derived transforming growth factor beta (TGFβ) to penetrate the stroma and drive development and persistence of myofibroblasts. Eventual repair of EBM leads to myofibroblast apoptosis when the cells are deprived of requisite TGFβ to maintain viability. The endothelium and Descemet's membrane may serve a similar function modulating TGFβ penetration into the posterior stroma-with the source of TGFβ likely being the aqueous humor.

[Descemet's membrane endothelial keratoplasty (DMEK): Analysis of a variation in Descemet's endothelial graft preparation]

INTRODUCTION

Descemet's membrane endothelial keratoplasty (DMEK) can replace just the corneal endothelium and respect the natural corneal anatomy. Currently, the technique of endothelial graft preparation remains manual and non-standardized.

PURPOSE

To report anatomic and functional results after DMEK, and compare two techniques of graft preparation.

METHODS

Single-center retrospective study, including 64 eyes of 64 patients undergoing DMEK, from September 2014 to February 2016 at Clermont-Ferrand University Medical Center. The "classic" preparation was used in 44 patients (group 1) and the "variant" preparation was used in 20 patients (group 2). An analysis of functional parameters (visual acuity), anatomy (pachymetry, corneal edema, endothelial cell count) and keratometry (sphere, cylinder, mean keratometry) was performed during the first postoperative year.

RESULTS

The mean follow-up was 10.0±2.5 months. The average preparation time was 12.3±8.1minutes, with 14.4±8.8 in group 1 versus 7.8±3.0 in group 2 (P<0.001). At six months, the best corrected distance visual acuity was significantly better in group 1 with an acuity of 0.28±0.28 LogMAR in group 1 and 0.37±0.30 LogMAR in group 2 (P<0.01). The best corrected near visual acuity was also better in group 1 at 6 months, with an acuity of 0.29±0.24 LogMAR (P<0.001) in group 1 and 0.37±0.28 LogMAR in group 2 (P=0.02). Improvement in visual acuity was continuous for the 2 groups. At 6 months, endothelial cell loss was greater in group 1 than in group 2, but the difference was not significant (P=0.44). Central corneal thickness was similar between the 2 groups. Finally, no change in keratometry parameters was found between preoperative data and 6 months in each group or between the two groups.

CONCLUSION

DMEK led to an improvement in all parameters as well as rapid visual rehabilitation. The new variation in preparation saved a considerable amount of time without decreasing graft survival or postoperative results.

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.

Wavelike Interface Opacities After Descemet-Stripping Automated Endothelial Keratoplasty: 7-Year Follow-up

PURPOSE

To report a case of wavelike interface opacities in a patient who underwent Descemet-stripping automated endothelial keratoplasty (DSAEK) and was managed conservatively over the course of 7 years.

METHODS

A 65-year-old woman underwent DSAEK for pseudophakic bullous keratopathy. Textural wavelike opacities were noted in the graft-host interface 6 days postoperatively without evidence of anterior segment inflammation. The patient's vision was also initially limited by the presence of cystoid macular edema (CME). Six months postoperatively, CME had resolved but the patient's vision failed to improve better than 20/80 because of the persistent dense interface opacities. The patient refused to undergo graft exchange despite a suboptimal visual result and she therefore was observed over time.

RESULTS

The interface opacities started to regress and her visual acuity improved to 20/30 by 9 months postoperatively. The opacities became gradually less prominent over the next few years, and at 7 years postoperatively, her best-corrected vision was 20/25.

CONCLUSION

In this case, observation of this post-DSAEK complication rather than surgical intervention resulted in a favorable long-term visual outcome.