Endothelial Migration and Regeneration after Penetrating Trauma Injury in a Deep Anterior Lamellar Keratoplasty Graft: Case Presentation and Literature Overview

Background: Traumatic injuries in eyes previously treated with Deep Anterior Lamellar Keratoplasty (DALK) can lead to ruptures in the Descemet Membrane (DM) and damage to the corneal endothelium, a crucial layer for maintaining corneal clarity. Due to cell cycle constraints, the human corneal endothelium cannot proliferate; instead, it compensates for injury through cell enlargement and migration from adjacent areas. Methods: This study examines a notable case of corneal endothelial cell migration following a penetrating eye injury in a patient previously treated with DALK for keratoconus, supplemented by a review of relevant literature to contextualize the regenerative response. Results: A 39-year-old male with a history of DALK suffered a traumatic eye injury, resulting in damage to the Descemet Membrane and loss of the crystalline lens. After primary repair and considerations for further surgery, the patient's cornea cleared remarkably, with an improved visual acuity. This demonstrates the DM's potential for self-repair through endothelial cell migration. Conclusions: The outcomes suggest that delaying corneal transplant surgery for up to 3 months following Descemet Membrane injury due to ocular trauma could be advantageous. Allowing time for natural healing processes might eliminate the need for further invasive surgeries, thereby improving patient recovery outcomes.

[Modern techniques and features of selective keratoplasty]

Selective keratoplasty involves replacing the affected layers of the cornea with similar donor tissue. In case of pathological changes in the middle and posterior stroma, deep anterior lamellar keratoplasty (DALK) is performed. Chronic corneal edema caused by endothelial dysfunction is an indication for endothelial keratoplasty - Descemet membrane endothelial keratoplasty (DMEK) or Descemet Stripping Endothelial Keratoplasty (DSAEK). Compared to penetrating keratoplasty (PK), these operations are characterized by a low risk of damage to intraocular structures and a relatively short rehabilitation period. Complications of selective keratoplasty include the formation of a false chamber between the lamellar graft and the recipient's cornea, ocular hypertension during anterior chamber air tamponade. Persistent epithelial defect can be a sign of primary graft failure in DALK, DSAEK and DMEK. Selective keratoplasty is characterized by a lower incidence of immune rejection than PK. In some cases, DALK can be complicated by corneal changes related to suture fixation of the graft. Long-term postoperative use of topical glucocorticoids can cause ocular hypertension and cataracts.

Efficient reduction of the scrolling of Descemet membrane endothelial keratoplasty grafts by engineering the medium

The Descemet Membrane Endothelial Keratoplasty (DMEK) procedure for corneal transplantation is challenging due to the need to unscroll the donor graft within the recipient's eye. This process of unscrolling is complex, time-consuming, leads to a loss of endothelial cells and, most importantly, can negatively impact the graft's adhesion and integration with the host tissue after surgery. This problem is particularly evident when the graft is young. However, the physics behind this scrolling is not well understood, and therefore no sustainable solution is attained. Here, we propose that the concentration gradient of the medium used during transplant leads to a displacement gradient across the graft thickness, resulting in an out-of-plane folding or scrolling of the graft tissue. Using chitosan bilayer-based experimental models, it is experimentally demonstrated that this diffusion-coupled-deformation phenomenon can successfully explain why younger donor grafts tend to scroll tighter than older ones. Most importantly, we illustrate here through experiments that the medium can be engineered to reduce the scroll tightness and thus reduce the surgical inconveniences and improve post-transplant recovery. STATEMENT OF SIGNIFICANCE: This paper addresses a major issue that surgeons face while doing Descemet Membrane Endothelial Keratoplasty (DMEK) in unscrolling grafts during the graft insertion procedure. The currently used tapping method to unscroll the graft inside the patient's eye significantly reduces endothelial cell count, thus affecting its lifetime. Surprisingly, the physics behind graft scrolling is not well understood, so no sustainable solutions are proposed by the medical community. In this work, we present the underlying mechanism of DMEK graft scroll and illustrate experimentally the reason for scroll tightness through a chitosan bilayer based experiment model. Most importantly, we have successfully demonstrated that the preserving medium of the grafts can be engineered to reduce scroll tightness.

ROCK Inhibitors in Corneal Diseases and Glaucoma-A Comprehensive Review of These Emerging Drugs

Rho kinase (ROCK) inhibitors have gained significant attention as emerging novel treatment options in the field of ophthalmology in recent years. The evidence supporting their efficacy in glaucoma and corneal pathology includes both in vitro and clinical studies. Among the available options, ripasudil and netarsudil have emerged as the leading ROCK inhibitors, and some countries have approved these therapeutic options as treatments for glaucoma. Various dosing regimens have been studied, including monotherapy and combination therapy, especially for patients with secondary glaucoma who are already on multiple medications. Another rising application of ROCK inhibitors includes their use as an adjunct in surgical procedures such as Descemetorhexis Without Endothelial Keratoplasty (DWEK), Descemet Stripping Only (DSO) to accelerate visual recovery, glaucoma surgeries to reduce scarring process and allow better intraocular pressure (IOP) control, or after complicated anterior segment surgery to treat corneal oedema. This article provides a comprehensive overview of the existing literature in the field, offering recommendations for prescribing ROCK inhibitors and also discussing patient selection, drug efficacy, and possible adverse effects.

Recent and Evolving Therapies in the Management of Endothelial Diseases

Corneal endothelium is the innermost layer of the cornea which has both barrier and pump function and very important to maintain cornea clarity. Unlike epithelium, endothelium does not have regenerative potential; hence, endothelial damage or dysfunction could lead to corneal edema and visual impairment. Advanced corneal transplantation which involves selective replacement of dysfunctional endothelium has led to improved and faster visual rehabilitation. But in recent times, alternative therapies in the management of corneal edema and endothelial diseases have been reported. In this review, we aim to give a comprehensive review of various strategies for the management of corneal endothelial dysfunction in order to give treatment which is precisely tailored for each individual patient. A review of all peer-reviewed publications on novel strategies for the management of endothelial dysfunction was performed. The various approaches to the management of endothelial dysfunction are compared and discussed. Shortage of human donor corneas globally is fuelling the search for keratoplasty alternatives. Corneal endothelial dysfunction can be caused following surgery, laser or corneal endothelial dystrophies which could be amenable to treatment with pharmacological, biological intervention and reverse the endothelial dysfunction in the early stages of endothelial failure. Pharmacological and surgical intervention are helpful in cases of good peripheral endothelial cell reserve, and advanced cases of endothelial cell dysfunction can be targeted with cell culture therapies, gene therapy and artificial implant. Treatment strategies which target endothelial dysfunction, especially FECD in its early stages, and gene therapy are rapidly evolving. Therapies which delay endothelial keratoplasty also are evolving like DSO and need more studies of long-term follow-up and patient selection criteria.

Deep anterior lamellar keratoplasty following thermokeratoplasty assisted epikeratophkia: A novel two-stage one-graft method to treat acute corneal hydrops

Purpose

To evaluate the clinical effects of deep anterior lamellar keratoplasty (DALK) using a single graft after thermokeratoplasty assisted epikeratophakia for the treatment of acute corneal hydrops.

Methods

This novel surgical procedure was performed on seven eyes of seven patients between 2019 and 2020. The procedure combines a first-stage surgery of thermokeratoplasty assisted epikeratophkia with intracameral sterile air injection and a second-stage surgery of DALK using the same corneal graft for both procedures. Main outcome measures included pre- and postoperative corrected distance visual acuity (CDVA) and anterior segment optical coherence tomography (AS-OCT) parameters. Corneal transparency, epithelization, and the presence of neovascularization, were evaluated at the 1-year follow-up visit.

Results

Corneal edema resolved rapidly in six of the seven cases. The mean central corneal thickness was significantly reduced from baseline to 1 day, 1 week, 1 month, and 2 months after the first-stage surgery (P < 0.0001). At a mean of 2.1 ± 0.7 months after the first-stage surgery, DALK was successfully performed in all cases. Six months later, the mean central corneal thickness was 611 ± 31 μm and the mean thickness of the recipient's residual stroma bed was 20 ± 6 μm at the central corneal area. Mean LogMAR CDVA improved from 1.74 ± 0.34 at baseline to 0.20 ± 0.11 after DALK (P < 0.0001). No postoperative complications appeared in our case series during the 1-year observation period.

Conclusion

Very good visual results were obtained with a novel technique (thermokeratoplasty assisted epikeratophakia followed by DALK using the same corneal graft) in the treatment of acute corneal hydrops.

Late Descemet membrane detachment after uneventful cataract surgery

Purpose

To report 5 patients with late Descemet membrane (DM) detachment after uneventful cataract surgery.

Observations

After a retrospective chart analysis of consecutive patients that developed DM detachment after uneventful cataract surgery, six eyes of five patients were enrolled. In all cases, patients reported good vision initially after cataract surgery. Within days to months, these patients developed late DM detachment with decreased vision. In one patient, the detachment affected both eyes. Filtered air or diluted sulfur hexafluoride were injected in the anterior chamber to tamponade the DM detachment. In five eyes, the cornea cleared after DM reattachment. In two eyes of the same patient, DM reattached spontaneously requiring no further surgical intervention. In one patient, the Descemet failed to reattach and required an endothelial keratoplasty.

Conclusion and importance

Descemet membrane detachment may occur after uneventful cataract surgery. Filtered air or long-lasting intraocular gas may be used to reattach DM. Spontaneous DM reattachment may also occur and surgeons should be aware of this to avoid unnecessary procedures.

The Descemet Membrane Endothelial Keratoplasty (DMEK) "Wave Maneuver"

A novel technique for Descemet membrane endothelial keratoplasty (DMEK) graft handling and centration without the endothelium touching the posterior part of the anterior chamber (AC), is presented here. It is particularly suitable for vitrectomized eyes, deep AC, and AC intraocular lenses (ACIOLs), potentially reducing surgery time and endothelial cell loss during surgery. This retrospective interventional case series includes 27 eyes with complex ocular pathology. All utilized a “Wave maneuver” to center an early elevated graft without completing graft centration on the bottom of the AC. Successful graft attachment and centration were evaluated intra and post-operatively. Best-corrected visual acuity (BCVA), central corneal thickness (CCT), and donor endothelial cell density (ECD) were measured pre-operatively, and three and six months post-operatively. DMEK grafts were successfully attached and centered in all cases. No maneuver-related complications were observed intraoperatively. BCVA improved from a pre-operative 0.2 ± 0.63, to 0.43 ± 0.49 and 0.76 ± 0.51 at the three- and six-month follow-ups, respectively (p < 0.01). CCT decreased from a pre-operative 742 ± 118, to 546 ± 87 and 512 ± 67 at three and six months, respectively (p < 0.01). ECD decreased from 2878 ± 419 cells/mm2 to 1153 ± 466 cells/mm2 at three and six months, respectively (p < 0.01). The “Wave maneuver” may be very beneficial in DMEK cases where the AC is either very deep or the bottom of the AC is compromised. The “Wave maneuver” learning curve was brief.

Scheimpflug Backscatter Imaging of the Fibrillar Layer in Fuchs Endothelial Corneal Dystrophy

A central collagen-rich subendothelial fibrillar layer (FL) correlates with areas of accentuated loss of corneal endothelial cells in advanced Fuchs endothelial corneal dystrophy (FECD). The present study sought to investigate whether the FL may be visualized by en face Scheimpflug backscatter imaging in vivo.

DESIGN

Retrospective analysis of a prospective observational case series.

METHODS

A total of 34 eyes (34 subjects) undergoing Descemet membrane endothelial keratoplasty (DMEK) surgery with preoperative high-quality Scheimpflug backscatter imaging data were included. The Descemet endothelium complex (DEC) was retrieved during DMEK surgery, and immunofluorescence staining was performed for collagens I, III, and IV. The FL morphology in en face Scheimpflug backscatter and immunofluorescence imaging was compared and agreement of FL parameters was analyzed using intraclass correlation coefficients (ICC) and Bland-Altman plots.

RESULTS

Scheimpflug backscatter imaging delineated the FL in 26 eyes and was FL negative in 8 eyes with deviation compared to immunofluorescence in 1 case and good agreement of morphology characteristics. Horizontal caliper diameter ± SD was 4.84 ± 0.85 mm, vertical caliper diameter was 3.92 ± 0.78 mm, maximum caliper diameter was 5.12 ± 0.82 mm, and surface area was 12.43 ± 4.74 mm². Compared to immunofluorescence imaging, mean difference (95% limits of agreement) and intraclass correlation coefficients were for horizontal caliper diameter 0.13 mm (-0.81 to 1.1 mm) and 0.88, vertical caliper diameter 0.23 mm (-0.76 to 1.2 mm) and 0.81, maximum caliper diameter 0.06 mm (-1.1 to 1.2 mm) and 0.86, and surface area 1.4 mm² (-3.9 to 6.7 mm²) and 0.85.

CONCLUSIONS

Scheimpflug backscatter imaging facilitates visualization of the FL in advanced FECD eyes, offering the potential to identify particularly diseased areas of the FECD endothelium in vivo.

Side press-and-release technique in endothelium-in descemet membrane endothelial keratoplasty(DMEK): A novel technique

PURPOSE

To describe a novel technique in unfolding an endothelium-in Descemet membrane (DM) graft.

METHODS

New surgical technique description.

RESULTS

We describe a novel technique that allows immediate and controlled unfolding of the endothelium-in Descemet membrane graft that was successful in 5 of our DMEK patients. It is essential to acquire this "side press-and-release" technique when the graft does not unfold spontaneously as expected.

CONCLUSIONS

This controlled and simple manoeuvre is an efficient and safe method of unfolding an endothelium-in DM graft.

Descemet membrane suturing to manage recurrent graft detachment in a patient with Descemet membrane endothelial keratoplasty on failed penetrating keratoplasty

A 65-year-old patient with history of keratoconus, mild cataract and penetrating keratoplasty over 30 years ago developed corneal oedema subsequent of graft failure with best corrected visual acuity (BCVA) of counting fingers. He underwent a successful cataract surgery combined with a 7.25 mm Descemet’s Membrane Endothelial Keratoplasty (DMEK) with Sodium Hexafluoride (SF6) gas. His cornea remained oedematous inferiorly at 4 weeks, despite two subsequent re-bubbling due to persistent DMEK detachment inferiorly. This was managed by three radial full thickness 10-0 nylon sutures placed in the inferior cornea along with intracameral injection of air. Following this, his anterior segment ocular coherence tomography (OCT) confirmed complete attachment of the graft, and the sutures were removed 4 weeks later. Unaided visual acuity was 20/63 and BCVA was 20/32 after 8 months. DMEK suturing can be helpful in persistent DMEK detachments, which is refractory to repeated re-bubbling due to uneven posterior surface of previous PK.

Two-year clinical outcome after Descemet membrane endothelial keratoplasty using a standardized protocol

PURPOSE

The purpose of this study is to evaluate 2-year clinical outcome after Descemet membrane endothelial keratoplasty (DMEK) in a variety of endothelial dysfunctions using a standardized protocol.

METHODS

: From a group of 230 eyes which underwent DMEK for Fuchs' endothelial corneal dystrophy (FECD), aphakic and pseudophakic bullous keratopathy, failed full thickness corneal transplants, ICE syndrome, failed DSEK, and TASS the clinical outcomes [best spectacle-corrected visual acuity (BSCVA), central endothelial cell density (ECD)] were evaluated before, and at 6, 12, and 24 months and the success rate, failure rate and postoperative complications were also analyzed.

RESULTS

Out of 230 eyes, 144 eyes (70%) had BSCVA 6/9 or better 2 years postoperatively. Mean donor ECD was 2692.23 (range, 2300-3436) cells/mm2 preoperatively, which was reduced to 1433.64 (range, 619.0-2272.0) cells/mm2 2 years after DMEK surgery, indicating a mean reduction of 1258 cells/mm2 (46%) in ECD.

CONCLUSION

DMEK is a highly successful surgical procedure when following a standard protocol for treating diseases of the corneal endothelium providing a near perfect anatomic restoration and a high degree of visual rehabilitation.

Ex vivo excimer laser ablation of cornea guttata and ROCK inhibitor-aided endothelial recolonization of ablated central cornea

PURPOSE

To determine whether excimer laser ablation of guttae is a viable strategy for removal of diseased tissue in Fuchs' endothelial corneal dystrophy (FECD) on excised human Descemet membranes and whether an excimer laser-created wound on healthy human corneas ex vivo is recolonized with corneal endothelial cells.

METHODS

Descemet membranes of FECD patients and corneal endothelium of normal human corneas were ablated ex vivo using an excimer laser licensed for glaucoma surgery. Specimens were kept in cell culture medium supplemented with 10 μm of rho-kinase inhibitor ripasudil. Corneal endothelial cell regeneration was observed using light and electron scanning microscopy. Furthermore, the whole corneal samples were evaluated by haematoxylin/eosin staining and immunohistochemical analysis using antibodies against Na⁺ /K⁺ -ATPase.

RESULTS

Guttae and corneal endothelium could be ablated with an excimer laser without total ultrastructural damage to the Descemet membrane or stroma. Nearly complete endothelial wound closure was accomplished after 26-38 days in treated corneas. Light and electron scanning microscopy suggested the establishment of a layer of flat endothelial cells. Additionally, Na⁺ /K⁺ -ATPase expression could only be observed on the inner side of the Descemet membrane.

CONCLUSION

Our proof of concept study demonstrated that excimer lasers can be used to ablate diseased tissue from excised FECD Descemet membranes ex vivo. Additionally, corneal endothelial cells recolonize a previously ablated endothelial area in healthy human corneas ex vivo under treatment with ripasudil. Thus, our results are the first experimental basis to further investigate the feasibility of an excimer laser ablation as a graftless FECD treatment option.

Corneal endothelial cell abnormalities in X-linked Alport syndrome

Background: X-linked Alport syndrome results from the effect of COL4A5 mutations on basement membranes in the kidney, ear and eye. This study investigated individuals with X-linked Alport syndrome for corneal abnormalities.Patients and Methods: Six men and four women from 8 families with genetically-diagnosed X-linked Alport syndrome underwent ophthalmological examination including slit lamp examination and corneal endothelial specular microscopy. Results for corneal microscopy for men and women with X-linked disease were compared separately with the mean values for age- matched normals using the student's t test.Results: Five of the 6 men had end-stage kidney failure, all 6 had a hearing loss, three had lenticonus, and three had a central fleck retinopathy. Two men had a history of recurrent corneal erosions but no evidence of posterior polymorphous corneal dystrophy. None of the four women had kidney failure, but two had a hearing loss, and two had a central fleck retinopathy. One woman, whose son had recurrent corneal erosions, also had erosions, but no features of a posterior polymorphous corneal dystrophy.Corneal specular microscopy demonstrated abnormalities in affected men and women, with larger endothelial cells (p = .0001 in men, p = .004 in women) fewer 6-sided cells (p = .0001, p = .001 respectively) and reduced cell density (p = .03, p = .02 respectively) than normal.Conclusions: Recurrent corneal erosions are common in men and women with X-linked Alport syndrome, but posterior polymorphous corneal dystrophy is rare. The abnormal corneal endothelial cells in affected men and women are consistent with an abnormal Descemet membrane, and the reduced cell density resembles the reduced podocyte numbers found in the Alport glomerulus.

Descemet membrane detachment

Descemet membrane detachment (DMD) is a potential vision-threatening complication that occurs most commonly after cataract surgery. DMD has also been reported to occur in various other surgeries such as keratoplasty, iridectomy, vitrectomy, trabeculectomy, holmium laser sclerostomy, alkali burn, and viscocanalostomy. Major risk factors include advanced age, preexisting endothelial diseases like Fuchs dystrophy or abnormality in the Descemet membrane and stromal interface, hard cataract, prolonged surgical time, ragged clear corneal incisions, and inadvertent trauma with blunt instruments or phacoemulsification probe. Most DMDs are peripheral and resolve spontaneously. Large, central DMDs if not managed appropriately may lead to corneal decompensation and opacification. Several authors have classified DMD depending on its configuration, height, extent, length, and position with respect to pupil. Anterior segment optical coherence tomography has been used to confirm and classify DMD and can also aid in deciding the management plan. Spontaneous reattachment of the DM with conservative management may occur in cases with small, peripheral, planar DMD with nonscrolled edges. Cases with nonplanar, central DMD, scrolled edges, and length >2 mm, however, have to be managed surgically. Descemetopexy is the gold standard for the management of DMD. Other management options include mechanical tamponade, suture fixation, descemetotomy, interface drainage, and keratoplasty. Prompt diagnosis and timely management often leads to a good visual outcome.

Use of Fibrin Glue in the Management of Descemet Membrane Perforation during Deep Anterior Lamellar Keratoplasty

PURPOSE:

To describe the use of fibrin glue to seal Descemet membrane (DM) microperforation and macroperforation during deep anterior lamellar keratoplasty (DALK).

METHODS:

A retrospective chart review was performed on patients who had DM perforation managed by fibrin glue during DALK at King Khaled Eye Specialist Hospital (KKESH) between June 2014 and February 2019.

RESULTS:

One thousand two hundred and eighty-eight DALK surgeries were performed at KKESH during the study period. Fibrin glue was used to seal DM perforations in four cases of DALK for keratoconus.

CONCLUSION:

Fibrin glue is an effective method to seal DM microperforations and macroperforations during DALK, which reduces the rate of conversion to penetrating keratoplasty (PK), preserving the advantage of DALK over PK.

DMEK outcomes using nondiabetic grafts for recipients with diabetes mellitus

PURPOSE

To compare Descemet membrane endothelial keratoplasty (DMEK) outcomes using nondiabetic grafts in diabetic and nondiabetic recipients.

METHODS

All eyes that underwent DMEK between February 2013 and October 2016 (follow-up ≥3 months, without prior keratoplasty) were included. Recipients were divided into diabetic (insulin dependent [IDDM] or noninsulin dependent [NIDDM]) and nondiabetic groups. Main outcome measures included postoperative visual acuity, rebubble procedure rates, and graft failure rates.

RESULTS

Of 334 eyes (243 subjects) included for analysis, 63 eyes (18.8%) were from diabetic recipients. At each timepoint, best-corrected visual acuity trended lower for IDDM recipients compared to NIDDM and nondiabetic recipients. There were no statistically significant differences in rebubble rates of diabetic compared to nondiabetic recipients (20.6% vs. 12.9%, p = 0.17), or IDDM compared to nondiabetic recipients (27.3% vs. 12.9%, p = 0.08; hazard ratio 2.26). Overall, 13 grafts (3.9%) failed (mean follow-up, 565 days; range, 90-1293 days). Graft failures did not differ between diabetic and nondiabetic recipients (4.0% vs. 4.9%, p = 0.15) regardless of subgroup (p = 0.36).

CONCLUSIONS

DMEK provides excellent outcomes for patients with and without diabetes. DMEK outcomes were excellent with improvements in visual acuity and low rates of graft failure. Our findings were unable to determine differences between rebubble procedure rates but do emphasize the need for further research using stratified groups based on diabetes severity.

Effective Tissue Layer Separation of Donor Cornea for DMEK by Fluid Injection Between Descemet Membrane and Corneal Stroma: Results of First Series of Operations

AIM

To evaluate clinical outcomes of Descemet Membrane Endothelial Keratoplasty (DMEK) using a novel hydro-separation of donor Descemet membrane (DM) endothelial graft with 6 months follow up.

MATERIAL AND METHODS

In this retrospective single-center; single surgeon cohort study, 16 consecutive eyes underwent DMEK or combined DMEK and cataract surgery with DMEK donor graft hydro-separation. The hydroseparation method used Ringer’s solution injected by a syringe with a flat end cannula between DM and corneal stroma to separate DMEK graft from donors’ cornea. Endothelial cell count, corrected and uncorrected distance visual acuities (CDVA, UDVA), corneal astigmatism and keratometric values were evaluated before and 6 months after the surgery.

RESULTS

DMEK grafts were successfully hydro separated, without a membrane tear in all cases and successful adhesion to recipient corneas was achieved in all cases. Overall CDVA improved significantly (p < 0.0001) from preop.0.69 logMAR (0.45–0.92, 95%CI) to 0.1 logMAR (0.04–0.15) 6 months postop. However UDVA was slightly worse in cataract combined cases 0.38 logMAR (0.18–0.43) vs 0.3 logMAR (0.14–0.61) in DMEK cases at 6 months. Corneal astigmatism K2-K1 improved significantly (p=0.0137) from preop. mean 2.89 D (0.19–0.43) to 0.98 D (0.48–1.48) 6 months postop.

CONCLUSION

Hydro-separation is fast and effective donor graft preparation method for DMEK. The DMEK using donor graft hydro-separation results in improved vision and induces a low amount of astigmatism at 6 months follow up. Further clinical data are needed to confirm the success rate and to explore optimization of the selection of IOLs in combined cataract cases

Hydrophilic intraocular lens opacification after repeated intracameral gas injection for Descemet membrane detachment

Descemet membrane detachment (DMD) is a complication of a variety of eye procedures that can result in severe visual loss. We report a new case of the condition, in a highly myopic patient that had undergone cataract surgery, and presented a macular hemorrhage during the intervention. DMD was successfully treated with a combined technique of intracameral gas injection and transcorneal suturing. Following resolution of this complication, intraocular lens opacification was observed.

Correlation between age and corneal edema in pediatric patients with Peters anomaly

PURPOSE

To evaluate corneal edema in different-aged pediatric patients with Peters anomaly and to correlate in vivo with ex vivo histopathologic findings.

METHODS

A retrospective cross-sectional study was performed. The medical records of patients diagnosed with Peters anomaly who underwent examination under anesthesia (EUA) between 2011 and 2015 were reviewed. Eyes in which central corneal thickness (CCT) measurements were taken were included. The thickest point in the CCT pachymetric map was used to objectively quantify corneal edema. Correlation between CCT and age was calculated. Additionally, a retrospective review of histopathologic studies of excised corneal buttons from pediatric eyes with Peters anomaly between 2011 and 2015 was performed.

RESULTS

Eighteen eyes of 12 children were included. Mean age was 14 ± 15 months, and mean CCT was 842 ± 304 µm. A significant inverse correlation was noted between the CCT and the age of the patients, with lower CCT values in older children (r = 0.6; P = 0.01). Seven excised corneal buttons that underwent penetrating keratoplasty were reviewed. All corneal buttons showed absence of Descemet membrane and localized absence of endothelium. However, three specimens showed presence of corneal endothelium in areas of absent or attenuated Descemet membrane.

CONCLUSIONS

In Peters anomaly, the CCT decreases with age, possibly due to a decrease in corneal edema. Histopathologic studies show cases of endothelial expansion in areas of absent or attenuated Descemet membrane. This may contribute to improved endothelial function and decreased edema with age.

Does Fluid Temperature Affect Corneal Endothelium-Descemet Membrane Scroll Formation? An In Vitro Study

Objectives:

To investigate whether unfolding time of Descemet membrane (DM) graft rolls changes at various fluid temperatures.

Materials and Methods:

The study was prospective, ex vivo, and experimental. The study was conducted at the tertiary center for corneal disease in Adana Numune Training and Research Hospital between June 2014 and June 2015. DMs were divided into 4 categories according to baseline roll tightness and these were distributed among 4 different groups using 4 different balanced salt solution (BSS) temperatures (8, 16, 23, and 36 °C). Sixteen donor corneas were obtained from the hospital eye bank.

Results:

DM roll formations may vary according to the donor cornea received. Some form tighter rolls while others can form a more open roll. No differences in roll tightness were observed in any of the DM rolls after 5 or 10 minutes in the different BBS temperatures. In all groups, neither tightening nor opening was observed in DM roll formations.

Conclusion:

Different BSS temperatures were found to have no effects on DM unfolding time in this study.

Mini descemet membrane stripping (m-DMES) in patients with Fuchs' endothelial dystrophy: A new method

We present two cases with focal corneal edema due to Fuchs’ endothelial dystrophy that were successfully treated with mini Descemet membrane stripping (m-DMES) (diameter of 3–4 mm; at the area of preexisting focal corneal edema) without endothelial replacement during cataract surgery. Specular microscopy demonstrated Fuchs’ endothelial dystrophy and histopathologic evaluation confirmed the diagnosis. Anterior segment optical coherence tomography and confocal microscopy were used for the evaluation of the corneal tissue recovery course after the surgical procedure. In both patients, we observed an initial aggravation of corneal edema in the area of DM removal for two months followed by gradual improvement. At four months postoperatively, corneal edema had completely regressed resulting in corneal clearance and visual acuity improvement in both cases. M-DMES without graft insertion represents a promising alternative surgical technique that could be applied in specific cases of Fuchs’ endothelial dystrophy with focal corneal edema.

[Noteworthy and controversial problems of deep anterior lamellar keratoplasty]

Corneal transplant is the main treatment for blindness caused by corneal diseases. The common methods of corneal transplant include penetrating keratoplasty and lamellar keratoplasty. With the advances of microsurgical instruments and technology in recent years, deep anterior lamellar keratoplasty (DALK) has gradually increased. Compared with conventional penetrating keratoplasty, the optical effects of DALK are not much different, but DALK has fewer complications. So DALK is expected to become the mainstream of corneal transplantation. Clinical surgeons try to promote DALK in China. However, there are certain learning curves and some controversies. Therefore, we discuss the controversial issues about DALK in this article.(Chin J Ophthalmol, 2017, 53: 164-166).

Clinical results of non-Descemet stripping endothelial keratoplasty

AIM

To investigate the impact of non-Descemet stripping endothelial keratoplasty (non-DSEK) on graft rejection rate, and its overall procedural effectiveness in patients.

METHODS

Non-DSEK was performed on 65 eyes of 64 patients, and the procedural outcomes, including rejection episodes, failure and dislocation of the grafts, best corrected visual acuity (BCVA), endothelial cell density (ECD), and other complications, were analyzed retrospectively.

RESULTS

Of the 65 eyes, 63 recovered from bullous keratopathy with a clear cornea. The mean follow-up time was 26.4mo (range, 6-84mo). The mean BCVA improved from 1.70 logMAR preoperatively to 0.54 logMAR at 3mo, 0.46 logMAR at 6mo, and 0.37 logMAR at 1y after surgery. The postoperative donor ECD of the 25 patients who successfully underwent specular microscopic examination was 1918±534 cells/mm² (range, 637 to 3056 cells/mm²), and the mean endothelial cell loss was 41.9% at 24mo postoperatively. One eye developed secondary glaucoma and required regrafting via penetrating keratoplasty (PKP). Another eye had postoperative graft failure due to rejection at 26mo. Postoperative graft dislocation occurred in eight eyes. All of the eight dislocated grafts were reattached using air reinjection.

CONCLUSION

Immunological graft rejection of the donor graft rarely occurs in non-DSEK. Therefore, non-DSEK is a safe, concise, and effective alternative to restore corneal decompensation when the Descemet membrane is disease-free.

Clinical characterization of posterior polymorphous corneal dystrophy in patients of Indian ethnicity

PURPOSE

To characterize the clinical presentation of posterior polymorphous corneal dystrophy (PPCD) in eyes of Indian ethnicity.

DESIGN

Retrospective cohort study from January 1995 to December 2015.

PARTICIPANTS

Patients with the diagnosis of posterior polymorphous corneal dystrophy.

METHODS

Medical records of the patients were reviewed for clinical presentation. Histology of corneal specimens of those that underwent keratoplasty was assessed.

MAIN OUTCOME MEASURES

Descriptive analysis of clinical condition.

RESULTS

Mean age at first evaluation was 32.5 years (range 1-73 years), male:female = 35:18. Majority (44/53; 83 %) of the patients had bilateral involvement. 5/9 (44 %) patients with unilateral presentation were amblyopic in the affected eye. The clinical features documented were vesicles in 94 eyes, band-like pattern in 32 eyes, edema of varying degree in 23 eyes (12 patients, 1 patient was one eyed), and anterior segment changes in 1 eye. 8/45 (17 %) eyes had a regular astigmatism with steep axis >47 D (range 47.2-56.2 D). 16 eyes of 12 patients who had clinically evident corneal edema underwent keratoplasty. Mean age at keratoplasty was 58 years (range 1-73 years). 8 patients had penetrating keratoplasty (PK) and 8 had Descemet stripping endothelial keratoplasty (DSEK). Mean follow-up after keratoplasty was 4.2 years (1 month to 13 years). Except one, all grafts remained clear till the last follow-up. In all specimens, the Descemet membrane was grossly thickened.

CONCLUSIONS

In our study, 12/53 (22.6 %) patients required keratoplasty for visually significant corneal edema. Except one, all were older adults. The patients who needed keratoplasty were bilaterally afflicted and had visually significant cornea edema in both eyes. With a mean follow-up duration of 4.2 years after keratoplasty, no recurrences were noted.

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.

Overview of the Cornea: Structure, Function, and Development

The cornea is a transparent tissue with significant refractive and barrier functions. The epithelium serves as the principal barrier to fluid and pathogens, a function performed through production of tight junctions, and constant repopulation through differentiation and maturation of dividing cells in its basal cell layer. It is supported posteriorly by basement membrane and Bowman's layer and assists in maintenance of stromal dehydration. The stroma composes the majority of corneal volume, provides support and clarity, and assists in ocular immunity. The posterior cornea, composed of Descemet membrane and endothelium, is essential for stromal dehydration, maintained through tight junctions and endothelial pumps. Corneal development begins with primitive formation of epithelium and lens, followed by waves of migration from cells of neural crest origin between these two structures to produce the stroma and endothelium. Descemet membrane is secreted by the latter and gradually thickens.

The genetics of Fuchs' corneal dystrophy

Fuchs' corneal dystrophy (FCD) is a common late-onset genetic disorder of the corneal endothelium. It causes loss of endothelial cell density and excrescences in the Descemet membrane, eventually progressing to corneal edema, necessitating corneal transplantation. The genetic basis of FCD is complex and heterogeneous, demonstrating variable expressivity and incomplete penetrance. To date, three causal genes, ZEB1, SLC4A11 and LOXHD1, have been identified, representing a small proportion of the total genetic load of FCD. An additional four loci have been localized, including a region on chromosome 18 that is potentially responsible for a large proportion of all FCD cases. The elucidation of the causal genes underlying these loci will begin to clarify the pathogenesis of FCD and pave the way for the emergence of nonsurgical treatments.

Mutagenesis of mitochondrial DNA in Fuchs endothelial corneal dystrophy

Fuchs endothelial corneal dystrophy (FECD) is an age-related, slowly progressive disease, which may lead to loss of vision resulting from apoptosis of corneal endothelial (CE) cells, dysfunction of Descemet membrane (DM) and corneal edema. A growing body of evidence suggests that oxidative stress may play a major role in the pathogenesis of FECD and that mitochondria of CE cells are its main target. Mitochondrial DNA (mtDNA) is particularly prone to oxidative stress and changes in mtDNA were reported in FECD patients. In the present work we studied mtDNA damage and repair, mtDNA copy number, and the 4977bp common deletion in mtDNA in DM cells and peripheral blood lymphocytes (PBLs) isolated from FECD patients. PBLs from 35 FECD patients and 32 controls were challenged for 10min with hydrogen peroxide at 20μM and then left in a fresh medium for 3h, resulting in a decrease in mtDNA copy number in both groups. Damage to mtDNA was not fully repaired after 3h and the extent of remaining lesions was significantly higher in the patients than the controls. We observed a higher copy number and an increased extent of mtDNA damage as well as a higher ratio of the common 4977bp deletion in DM cells of FECD patients than the controls. Our results confirm that mutagenesis of mtDNA may be involved in FECD pathogenesis and disturbance in mtDNA sensitivity to damaging agent as well as changes in mtDNA damage repair along with alternations in mtDNA copy number may underline this involvement.

Ocular manifestations of monoclonal copper-binding immunoglobulin

The dense accumulation of copper in Descemet membrane and lens capsule is the characteristic manifestation of a circulating monoclonal antibody with strong affinity for copper. The overproduction of this monoclonal immunoglobulin may be associated with either multiple myeloma or a benign monoclonal gammopathy. Despite prolonged exposure to elevated serum copper, no other tissues in the body are adversely affected by this redox metal. We describe the clinical and pathological findings in a 46-year-old woman with this disorder.

Corneal Biomechanical Properties and their Correlates with Healing Process after Descemetic versus Pre-Descemetic Lamellar Keratoplasty

PURPOSE

To evaluate the influence of the wound-healing process on corneal biomechanics in patients after 2 types of deep anterior lamellar keratoplasty: Descemetic with total stromal resection vs pre-Descemetic with deep stromal dissection.

METHODS

This prospective comparative study consisted of 32 eyes of 32 patients. Patients were divided into 2 groups: Descemetic (17 eyes) and pre-Descemetic (15 eyes). Reichert ocular response analyzer was used to measure corneal hysteresis (CH) and corneal resistance factor (CRF) at 1 and 3 months postoperatively. Central corneal thickness (CCT) was measured using ultrasonic pachymetry. In vivo confocal microscopy was also used to study the corneal wound-healing process and to correlate these events with the corneal biomechanics postoperatively in both groups.

RESULTS

Both mean CH and mean CRF were significantly lower in the Descemetic than the pre-Descemetic group at 1 and 3 months postoperatively (p≤0.0001). The reflectivity of activated keratocytes at both the interface and wound edge was less in the Descemetic than the pre-Descemetic group at all times as revealed by the confocal microscopy. No statistically significant difference in mean CCT was found between both groups at 1 and 3 months. Subsequent and progressive decrease in interface reflectivity of activated keratocytes was presented in both groups.

CONCLUSIONS

Healing process at the interface is key to optimal corneal integrity. In the pre-Descemetic group, stroma-to-stroma healing stimulated more activated keratocytes and hence stronger healing response, providing superior corneal biomechanics. Significant positive correlation between the intensity of the keratocyte activation and corneal integrity was found.