Neodymium:YAG laser optical opening for retained Descemet's membrane after penetrating keratoplasty

Successful management of a retained host Descemet's membrane after penetrating keratoplasty (PKP) - A case report

INTRODUCTION AND IMPORTANCE

To report the 21st case showing the rare occurrence of retained Descemet's membrane (DM) following penetrating keratoplasty (PKP). We intend to investigate possible etiologies, expected sequelae, and outcome of neodymium-dpoed yttrium alumnium garnet (Nd: YAG) laser membranectomy.

CASE PRESENTATION

Our case is a 74-year-old male who underwent PKP surgery in the right eye secondary to corneal decompensation following cataract surgery in addition to corneal thinning secondary to superficial keratectomy related to the pre-existing climatic droplet keratopathy (CDK). Postoperative assessment revealed a retro-corneal membrane within the anterior chamber, which was affecting his vision.

CLINICAL DISCUSSION

Based on the post-operative course and the decreased vision as an indication for intervention, it was decided to excise the retained DM. Membranectomy with Nd: YAG laser was performed, and the patient's visual acuity measurement improved from 20/400 to 20/25. However, the endothelial cell count decreased from 1479 to 520 cells/mm2 (35 % loss) at 15 months post YAG membranectomy with clear graft. Histopathological examination confirmed the clinical suspicion of a retained DM, since it was absent in the submitted host corneal tissue in addition to the pre-existing CDK.

CONCLUSION

Retention of DM following PKP is a rare but possible complication and high index of suspicion is required for proper diagnosis and management to obtain better visual outcome. Nd: YAG laser membranectomy was effective in excising the retained DM and improving vision. Endothelial cell loss following Nd: YAG laser membranectomy as a complication was observed and should be addressed during the treatment plan.

Surgical alternatives to keratoplasty in microbial keratitis

Penetrating keratoplasty is often required in microbial keratitis not responding to the standard treatments available or the development of complications like corneal perforation. Performing keratoplasty in microbial keratitis has several challenges, the major ones being the availability of donor corneal tissue and the poor success of the corneal graft performed in such a setting. For overcoming these challenges, several alternatives to keratoplasty have been described. Broadly, these options could be categorized into autologous tissues such as conjunctival and tenon tissue, synthetic products like tissue adhesives and therapeutic contact lenses, or biological tissues like amniotic membrane graft. These alternative modalities are not universal. They have their specific indications in microbial keratitis. Most of these alternatives are useful only for small corneal perforations. While autologous tissues are cost-effective and readily available, lack of tectonic support is a significant limitation. Tissue adhesives are excellent alternatives in terms of tectonic support, but surface irregularity and tissue reaction are their potential limitations. The amniotic membrane is useful for small corneal perforations, but availability, cost, and poor tectonic support restrict its use. Herein, we discuss these various alternatives to keratoplasty in microbial keratitis, their indications, advantages, disadvantages, and the various techniques of performing these procedures.

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.

Triamcinolone Acetonide-Assisted Descemetectomy for Retained Descemet Membrane

We present a case of decreased vision due to the presence of retained Descemet membrane (DM) following Descemet stripping automated endothelial keratoplasty (DSAEK) and penetrating keratoplasty (PKP). A 78-year-old male presented postoperatively from PKP after previous failed DSAEK with retained DM. We present a unique technique for combined surgical resection using bimanual vitrectomy and forceps excision assisted by triamcinolone acetonide for membrane visualization. Histopathological evaluation confirmed incomplete DM removal during the PKP. With surgical excision, there was an improvement in best spectacle-corrected visual acuity from 20/80 to 20/30.

Removal of Retained Descemets Membrane Using Femtosecond Laser

We present a unique method of retrocorneal membrane removal with a femtosecond laser (FSL). A 22-year-old male who had undergone penetrating keratoplasty had a retained retrocorneal membrane and a double anterior chamber postoperatively. The membrane was dissected completely with the FSL and the free-floating membrane was removed. Histopathological evaluation confirmed the diagnosis of retained Descemets membrane (DM). There was improvement in uncorrected visual acuity from 20/300 to 20/50. Central corneal endothelial cell count was 810 cells/mm² preoperatively and 778 cells/mm² postoperatively. Inadvertent retention of DM may be safely treated with the FSL. Clarity and viability of the existing graft can be maintained.

A new clinico-tomographic classification and management algorithm for Descemet's membrane detachment

OBJECTIVE

To propose a new clinico-tomographic classification of Descemet's detachment (DD).

METHODS

Interventional case series of 35 eyes with DD were clinico-tomographically classified as: (1)Rhegmatogenous DD (RDD)-lax, free floating DM secondary to DM tear/hole/dialysis; ASOCT showing undulating linear signal with total length equalling overlying stromal arc length. (2) Tractional DD (TDD)-foreshortened, taut DM with tractional/fibrotic component; ASOCT showing detached DM chord length less than overlying stromal arc length. (3) Bullous DD (BDD)-bulge of DM into AC in absence of DM break or needle puncture break too small to allow egress of contents; ASOCT showing convex signal. (4) Complex DD (CDD)-Complex variants and combinations seen clinically and on ASOCT.

RESULTS

RDD was most common (n=23), 19 were RDD with tear (post-surgical) treated by observation(n=3)/pneumodescemetopexy(n=16), 2 were RDD with hole due to inadvertent DM perforation in deep anterior lamellar keratoplasty treated by pneumodescemetopexy and fibrin glue, 2 were RDD with dialysis post-Descemetorhexis in Descemet's Membrane Endothelial Keratoplasty, not requiring treatment. TDD (n=4) was treated by relaxing Descemetotomy (n=3) or EK (n=1, poor endothelium); BDD (n=3) with two improving spontaneously; CDD (n=5) treated by refloatation with air (n=3)/EK (n=1)/penetrating keratoplasty (n=1).

CONCLUSION

Treatment and prognosis of DD varies based on etio-morphology. This classification allows systematic approach for diagnosis, management and prognostication.

Corneal graft failure following Nd:YAG laser membranotomy for inadvertent retained descemet's membrane after penetrating keratoplasty

Retained Descemet's membrane (DM) following penetrating keratoplasty (PKP) is a rare finding that may reduce visual acuity following opacification or endanger the graft endothelium. The association between Nd:YAG laser membranotomy and corneal graft failure is reported. Five of 1,350 patients (0.37%) undergoing PKP for pseudophakic bullous keratopathy or graft failure between 1986 and 2008 presented with inadvertent retained DM located close to the graft endothelium. The membrane opacified within 3 to 4 months, reducing the patients' vision. Nd:YAG laser membranotomy was performed using low energy and few pulses. Patients' visual acuity improved from 6/40 to 6/90 before treatment to 6/15(-) to 6/20 at 2 weeks following membranotomy. However, the corneal graft decompensated within 6 to 8 weeks following this procedure, necessitating repeat PKP, with removal of the retained DM. Nd:YAG laser membranotomy may lead to corneal graft failure due to shockwave damage created by the laser pulses, focused near the endothelial surface.

Inadvertent Retention of Descemet Membrane in Penetrating Keratoplasty

PURPOSE

To present a case of inadvertently retained Descemet Membrane (DM).

METHODS

Case report.

RESULTS

A 41-year-old male with previous history of retinal detachment surgery underwent a repeat penetrating keratoplasty; the first graft decompensated secondary to silicone oil. Postoperatively, an inadvertently retained DM was observed forming a physical barrier to the silicone oil.

CONCLUSION

Retained DM is a rare complication of penetrating keratoplasty, with only a few cases reported in the literature. This membrane served a protective role from the effects of silicone oil on the donor cornea but later opacified and required surgical intervention.

Retained Descemet's membrane after penetrating keratoplasty

Retained Descemet's membrane is a rare complication of penetrating keratoplasty (PKP). The membrane can become progressively opaque and threaten the health of the corneal graft. We report such a case involving a 53-year-old man. Simultaneous surgical removal of the membrane and phacoemulsification with intraocular lens implantation were performed 3 months after PKP. The graft remained clear and best corrected visual acuity was 20/20 2 years after secondary surgery.