Descemet's membrane detachment: An updated comprehensive review of etiopathogenesis, diagnosis, and management

Abstract

The Descemet membrane (DM) is the basement membrane of corneal endothelial cells, which are responsible for maintaining corneal transparency. DM detachment (DMD) can occur due to various reasons, with the most common etiology being post-surgical. Older age, blunt instruments, and faulty surgical technique predispose to the intraoperative or postoperative occurrence of DMD, and one should have a high index of suspicion for DMD in cases with unexplained or an atypical pattern of corneal edema after surgery. Prompt intervention for DMD management is imperative to effect early visual rehabilitation, decrease corneal morbidity, and avoid permanent damage leading to scarring of the cornea. Various classifications of DMD and management protocols have been described. Anterior-segment optical coherence tomography (AS-OCT) imaging is the most effective imaging to detect DMD and quantify its extent. Desmetopexy with air/gas is the initial treatment of choice and could be aided by suture fixation. Non-responsive cases might need endothelial keratoplasty.

Descemet membrane (DM) detachment (DMD) is a potentially serious and sight-threatening complication after surgery. The earliest description of DMD in the literature was by Weve et al. in 1927.[1] There are several risk preoperative and intraoperative risk factors for DMD. Spontaneous resolution of DMD can occur. Hence, the management of DMD is varied and primarily involves choosing between conservative management and surgical intervention. The surgical intervention is also governed by several parameters such as the nature of detachment, involvement of the visual axis, and the primary surgical situation.

This review is aimed at describing the pathogenesis, causes, and risk factors of DMD, as well as the various management approaches.

Methods

A literature search was carried out on PubMed (United States National Library of Medicine), Embase (Reed Elsevier Properties SA), Web of Science (Thomson Reuters), and Scopus (Elsevier BV) by using the keywords- “Descemet membrane,” “Descemet membrane detachment,” “classification of DMD,” and “management of DMD.” In total, 551 articles were screened. Case reports that did not add any new modality of treatment to the existing literature, articles unrelated to management, those with no full-text available, and foreign-language articles with no translation available were excluded. Eventually, 82 relevant articles that pertained to the management of DMD were shortlisted and reviewed.

Relevant Applied Aspects

1. Anatomy of the DM- Endothelium Complex

   The DM, the basement membrane for the corneal endothelial layer, is secreted by a single layer of endothelial cells. This endothelial layer maintains corneal de-turgescence and transparency. Any insult to this layer resulting in its severe/irreversible damage necessitates a posterior lamellar transplant. The DM is thicker than other basement membranes. It does not contain lamina lucida or lamina densa and is divided into anterior banded and posterior non-banded layers.[2] Anterior banded layer comprises sheets of collagen type VIII and proteoglycans arranged loosely. The posterior non-banded layer is more uniform.[2] At birth, it consists of an embryonic banded portion that is 3 microns thick. After birth, the posterior non-banded layer is secreted by the endothelial cells.[3] By the age of 70 years, the average The DM is 13 microns thick, including the original 3 microns of anterior banded/fetal DM. The stressed endothelial cells may secret an abnormal banded DM, which is termed the posterior collagen layer.

2. Attachments of the DM to the posterior stroma- Ultrastructural characteristics

   Electron microscopy has revealed that the DM is attached to the stroma by stromal fibers.[4] Stromal attachment to the DM is accomplished by 22.3-nm-thick stromal fibers that penetrate 0.20 microns into the DM. It is hypothesized that due to abnormalities in the interface matrix, the DM may detach regardless of the incision or the type of surgery.[5]

3. Natural course of DMD

   The natural course of DMD can vary. There are several reports of spontaneous reattachment of detached DM, although this is inconsistent and unpredictable. Several theories are proposed to explain the mechanisms of spontaneous reattachment. The endothelial cells continue to function to pump out fluid accumulated between the stromal and detached DM. As the fluid is pumped out, DM attachment can happen spontaneously. Ismail et al.[6] proposed a fluid mechanical model of buoyancy-driven aqueous humor flow in the anterior chamber around a DMD to explain spontaneous reattachment. Their analytical model is based on the lubrication theory limit of the Navier–Stokes equations.

Pathogenesis and Causative Risk Factors

The pathogenesis of DMD is elaborated in Flowchart 1. The etiologies for DMD can be varied and may occur due to the following causes:

Flowchart 1.

Flowchart of the pathophysiology of DMD

1. Genetic, congenital/inherent causes of DMD include the following:[7]

   1. Endothelial dystrophy- Fuchs corneal endothelial dystrophy and posterior polymorphous corneal dystrophy[8]

   2. Birth trauma and injuries.

2. Older age: Older age is a risk factor for DMD due to the age-related thickening of the DM, arcus (lipid degeneration), and peripheral degenerations that weaken the attachments between the DM and the posterior stroma.[9]

3. Other ocular disorders: DMD occurrence has been reported to be more common in eyes with pseudoexfoliation syndrome,[10] primary angle closure glaucoma,[11] and eyes undergoing intraocular surgery.

4. Iatrogenic factors: DMD incidence post cataract surgery ranges from 0.5%[12,13] to 43%[14] and 2.6% during extracapsular cataract extraction.[13] Denser cataracts and complicated surgery increase the risk, as do blunt instruments and poor techniques – such as improper hydration technique and injecting saline/antibiotics/viscoelastics in the posterior stroma.[15,16] DMD has been reported during IOL insertion too.[17,18] Clear corneal incisions are more likely to result in DMD, especially if the incision is ragged.[19]

   Both full thickness[20,21] and lamellar keratoplasties can lead to DMD.[22] These cases, like another case of pellucid marginal degeneration with late-onset DMD, were likely related to the recurrence of ectasia, due to differential tolerance of stretch for corneal stroma and DM.[23]

   In the case of deep anterior lamellar keratoplasty, the DM detaches due to inadvertent perforation during the surgery in over 2% of the cases.[24] Unrecognized type 2 bubble has been hypothesized to be another cause.[25] Other surgical interventions such as iridectomy, vitrectomy, trabeculectomy, and sclerotomy can also lead to DMD.[26]

5. Idiopathic: DMD has been reported in healed keratitis patients where no previous intraocular surgery has been performed.[27]

DMD in Specific Situations

The mechanisms that result in the occurrence of DMD differ in various intraocular procedures are as follows:

1. Following Cataract Surgery:

2. DMD occurs most commonly following cataract surgery (in both small-incision cataract surgery (SICS) and phacoemulsification procedure). The DM tends to detach from the descemetotomy tear at the incision site or at the side port entrance site. The reported incidence of vision-threatening DMD after extracapsular extraction and phacoemulsification was 2.6% and 0.52%, respectively.[13,26] Surgical risk factors include the usage of blunt instruments, inadvertent insertion of instruments in between corneal stroma and DM, inappropriate incisions (such as oblique, too anterior incisions, and shelved incisions), tight side-port incisions or phacoemulsification tunnel incisions that do not fit the cannula or the phacoemulsification probe, respectively, inadvertent injection of ocular viscoelastics or intracameral antibiotics in between the DM and stroma, handling sharp instruments in the shallow anterior chamber, and inexperienced surgeon.[8] Dai et al.[28] observed that a modified 2.2-mm incision that is internally enlarged to create a trapezoid shape might lead to lesser DMD. Higher total ultrasound time and higher cumulative dissipated energy are predisposed to DMD.[29] Femtosecond laser-assisted cataract surgery (FLACS) is also associated with a lower incidence of DMD.[30] Preoperative risk factors such as primary endothelial disorders can predispose to spontaneous DMD even in uneventful cataract surgery.

3. Following Keratoplasty (PK and DALK):

4. Spontaneous DMD has been reported after PK, 20 years after surgery for keratoconus,[20] 30 years after surgery for pellucid marginal degeneration,[31] and DALK for corneal ectasia.[23] The mechanical pulling effect of the presence of retro corneal membrane along the graft-host junction on the DM and progressive thinning and ectasia at the graft-host interface have been hypothesized to cause spontaneous DMD.[20] Decentration of donor trephine in large grafts could be a cause as the DM is thinner in the periphery.[21] DMD has been reported after penetrating[20] as well as lamellar keratoplasties.[22] Keratoplasties in ectatic disorders can present with DMD in the future due to progressive ectasia, and such cases were ultimately managed with endothelial keratoplasty.[20]

5. Unrecognized type 2 bubbles and micro-perforations are the common cause of DMD after DALK.

6. Following Glaucoma Surgeries (Trabeculectomy and Viscocanalostomy):

7. DMD is a rare but dreaded complication during trabeculectomy. Preoperative raised IOP leading to persistent edema may have weakened the adhesion between the stroma and DM.[11] A sudden release of the IOP may also contribute to it. A shallow anterior chamber in angle closure patients is also a risk factor.

8. Following Chemical injury:

9. DMD occurrence in eyes affected by chemical injury is due to inflammation and fibrosis in the anterior chamber. Severe cellular damage incites inflammatory retro corneal membrane, leading to tractional DMD.[32]

10. Following Birth trauma:

11. DM tears occur following forceps injuries. Injury to the globe during forceps delivery results in vertical linear tears in the DM, which can lead to DMD in the affected region. Localized, central to mid-peripheral corneal edema overlying the region of linear DM tears in the newborn following a forceps delivery is indicative of DMD.[33] This may go unnoticed and get diagnosed later due to the resultant astigmatism, amblyopia, or high myopia.[34]

12. Following interstitial keratitis:

13. Hemorrhagic detachment of the DM complicating corneal neovascularization following interstitial keratitis has been reported in syphilis.[35]

14. Following radial keratotomy (RK):

15. K. Chiba et al.[36] noted that mean endothelial cell density reduced significantly 6–30 months post RK. Yamaguchi et al. reported that 60 out of 80 follow-up patients of RK had corneal decompensation over a period of 10–20 years.[37]

16. Occurrence of DMD in a 43-year-old man 20 years following RK with spontaneous resolution noted in 8 months has been documented.[38] Spontaneous DMD has been reported in a post-RK patient after 8 years, likely due to the progression of ectasia.[39]

17. Following laser iridotomy

18. DMD has been reported post Nd:YAG laser iridotomy in a pseudo-exfoliation patient[40] or post argon laser in an angle-closure patient.[41]

19. Following phaco canaloplasty

20. DMD has been reported post phaco canaloplasty. M Orejudo de Rivas et al.[42] reported three cases of DMD post ab externo phaco canaloplasty procedures. Hemorrhagic DMD has also been reported.[43]

Classification of DMD

Several classifications of DMD have been described in the literature and are detailed in Table 1.

Table 1.

Classification of DMD

Name	Types of DMD	Characteristics
Mackool and Holtz classification[44]	Planar	Separation of DM from stroma <1mm in all areas
	Non-Planar	Separation between DM and stroma >1 mm in any area
Jain classification[45]	Mild DMD	Involving <25% of the cornea & peripheral
	Moderate DMD	Involving 25%–50% of cornea & peripheral
	Severe DMD	Involving >50% of cornea & central cornea
Jacob classification[46]	Rhegmatogenous DMD (most common)	Lax, free-floating DM secondary to tear/hole/dialysis of DM at Schwalbe's line	- use of blunt instruments in cataract surgery - In DALK due to micro-perforations, - Post Trabeculectomy or Trabeculotomy
	Tractional DMD	Foreshortened, stretched-out taut DM with fibrotic component	Traction of DM due to Inflammation, fibrosis, incarceration in the wound, Peripheral anterior synechiae, or suture
	Bullous DMD	Smooth bulge of DM into anterior chamber in the absence of DM break	- Post cataract surgery - Viscocanalostomy surgery
	Complex DMD	Complex configurations or combinations of one or more types of DMD-scrolled edges/macro folds	Intraocular surgery – DMEK or poorly reposited R-DMD

1. Samuel classification (1928) was given based on the pathological features.[47] This classification described DMD as either active (pushed back) or passive (pulled back and torn away).

2. Mackool and Holtz classification (1977), based on the height of detachment from the stroma, described the DMD as planar or non-planar.[44]

3. Jain classification (2013) is based on the extent of DMD.[45]

4. Jacob classification (2015) is based on the etiology, clinical features, anterior segment optical coherence tomography (AS-OCT) findings, intraoperative factors, and management protocol.[46]

5. HELP Algorithm (2015), based on Height, Extent, Chord Length, and Relation to the Pupil [Table 2],[48] recommended management strategies based on these.

6. Samarawickrama (2016) classification:

   In 2016, Samarawickrama et al.[49] classified DMD depending on the involvement of the visual axis as peripheral and central DMD and proposed management guidelines based on this.

7. Dua et al. classification (2020):[50] Three types of DMD were described in an OCT-based classification-

Table 2.

HELP Algorithm in DMD

Height of detachment from stroma	<100 µm	100–300 µm	>300 µm
Chord length is the total length of detached DM measured in AS-OCT using calipers	<1 µm	1–2 µm	>2 µm
Extent of detachment is classified depending on the area of the cornea involved	Zone 1: Central 5 mm	Zone 2: Paracentral 5–8 mm	Zone 3: peripheral >8 mm
Position of DMD based on the position with respect to the pupil	Till nasal/temporal pupillary border	Involving the pupil	Beyond pupil

Type 1- Pre-Descemetic layer and DM were detached together.

Type 2- Only the DM was detached

Type 3- Mixed, both were detached but also separated from each other

This classification was also used by Li YT et al.[51] in their classification of DMD post ocular surface burns.

Clinical Characteristics

Unexplainable/persistent corneal edema following intraocular surgeries such as cataract, keratoplasty, glaucoma surgeries, and radial keratotomy leads to the detection of DMD on careful slit-lamp examination. Common symptoms include delayed or poor visual improvement, foreign body sensation, and watering. Clinical examination reveals signs of DMD [Fig. 1] such as localized corneal edema on slit-lamp examination. The extent of DMD margins can be defined on slit-lamp evaluation depending on the visibility in accordance with the corneal haze. In the presence of significant corneal edema, details of the detached DM get obscured.

Figure 1.

(a) Post trabeculectomy DMD. (b) Spontaneous DMD in a keratoglobus patient (arrow showing DMD)

DMD, if localized, may spontaneously reattach, with subsequent scaring of the DM.

Permanent corneal decompensation would result in poor vision, resulting in continued discomfort from watering and foreign body sensation due to bullae formation. Timely management of DMD is required to mitigate corneal morbidity. Early intervention for endothelial damage with endothelial transplantation procedures (DSEK/DSAEK or DMEK) affords good visual rehabilitation in eyes with visual potential. Long-standing corneal edema in cases of DMD causes repeated bullae rupture, leading to anterior corneal scaring, necessitating penetrating keratoplasty for visual rehabilitation.

Investigations

Poor visibility of the anterior chamber in eyes with suspected DMD due to corneal edema requires investigative imaging modalities to diagnose, treat, and monitor the patient with DMD.

1. Anterior-segment optical coherence tomography (AS-OCT):

   AS-OCT imaging is a useful tool to recognize the extent and direction of DMD, especially in cases with poor corneal clarity due to edema [Fig. 2]. AS-OCT enables high-resolution cross-sectional images of the anterior segment through the relatively hazy cornea. DMD classifications based on AS-OCT imaging enables detailed outlining of management.[52] The HELP algorithm elaborates the recommended intervention in accordance with the extent and height of the DMD.[48] Large DMD in DALK surgery can be settled with microscope-integrated intraoperative OCT-aided descemetopexy with interface fluid drainage.

2. Ultrasound biomicroscopy:

   Ultrasound biomicroscopy (UBM) is also a useful imaging tool in accurately locating DMD and guiding the DM repair but is less often preferred to AS-OCT.[53] The major limitations include the need for a skilled technician and that it is a contact procedure requiring patients’ cooperation and is time-consuming. Comparison of the efficacy in diagnosing anterior chamber angle structures with AS-OCT and UBM observed AS-OCT to be superior, being a non-contact and faster procedure providing multiple higher resolution images of superior image quality.[54]

3. Gonioscopy in DMD:

   Gonioscopy can be of useful tool in peripheral DMD to assess the extent, length, and height of DMD.[14] However, the associated corneal edema usually tends to limit its use.

Figure 2.

(a) Preoperative AS-OCT in a patient with post-DALK DMD. (b) Post descemetopexy, day-1 AS-OCT showing the clearing of edema and attachment of the Descemet membrane

Management

Decision-making in the management of DMD depends on the careful preoperative evaluation of the age of the patient and the etiology of DMD. The extent of DMD, its area of separation, and its location are the most important parameters determining the management of DMD. Timely recognition and intervention are imperative to lessen morbidity and enable an optimal outcome in the management too DMD. In general, surgical intervention is considered in situations where the visual axis is involved to attain a quick restoration of vision. Non-response/slow response to a wait-and-watch approach is also an indication of surgical intervention.

The HELP algorithm recommendation for the management of DMD in relation to Height Length, and relation to the Pupil is as follows:[48]

1. DMD with length <1 mm and height <100 µm in any zone: medical management

2. DMD with length 1–2 mm and height 100–300 µm in zones 2 and 3: surgical management

3. DMD with length >2 mm and height >300 µm in zone 3: surgical management

4. If medical therapy fails at 4 weeks: surgical management.

Medical management with topical hyperosmotic agents and topical steroids under antibiotic cover is helpful. The use of intracameral gas is recommended for surgical intervention. Medical management in DMD helps to decrease corneal edema and inflammation. Adjunct topical therapy with hyperosmotic agents and anti-inflammatory and anti-glaucoma agents is helpful. A brief literature review of management is discussed in Table 3.

Table 3.

Management of DMD- literature review

Author	Type of study	Intervention	Outcome	Complication	Clinical implication
Marcon et al., 2002[26]	Retrospective, non-comparative interventional study	Medical management, SF6 injection	9/10 cases of medical management and 4/5 cases of SF6 injection successful	One case in each group needed penetrating keratoplasty	Large non-scrolled DMD may attach spontaneously. SF6 injection is an alternative to conservative management.
Chaurasia et al., 2012[55]	Prospective interventional study	Air injection	13/14 cases successful attachment of the Descemet membrane.	Two patients- raised IOP	Air descemetopexy is also effective in DMD management
Jain et al., 2013[45]	Retrospective	Air/C3F8 injection	Both air and C3F8 equally efficient in managing DMD. Higher risk of pupillary block with C3F8	3 out of 60 patients needed corneal transplants. 7 patients had pupillary block	Air is efficient in settling DMD
Jain and Mohan, 2014[56]	Retrospective interventional	Repeat descemtopexy with air/C3F8. Air was used twice in 4 patients, C3F8 in 5. In 4 patients, air used first and C3F8 later.	12/13 patients resolved	One patient needed endothelial transplant and one had pupillary block	Repeat descemetopexy should be considered before considering keratoplasty
Sharma et al., 2015[52]	Prospective interventional	AS-OCT was done and 25/37 cases had DMD. DMDs in the superior half of the cornea with a planar configuration were managed using air. Those with scrolled edges were managed using C3F8. DMDs in the inferior half of the cornea with planar or scrolled edges were managed using C3F8 injection.	All cases resolved. Cases without DMD were registered for keratoplasty.	Two patients had raised IOP and one patient needed repeat descemetopexy	AS-OCT is an important tool to diagnose DMD in hazy cornea and to determine the course of intervention- whether to inject air or C3F8
Garg et al., 2016[57]	Retrospective non-comparative interventional	C3F8 used	71.64% of cases- anatomical attachment, 74.63% of cases- visual acuity improved. Did not depend on location and extent of detachment. 100% reattachment with planar and 53.7% with non-planar detachment.	9 eyes- raised IOP, 3 eyes- visually significant scarring despite reattachment.	C3F8 descemetopexy is effective
Odayappan et al., 2018[8]	Retrospective	Air descemetopexy	78/110 had DM attachment. 15 patients- repeat injection- 9 were successful.	Appositional angle closure (18%), pupillary block (2.7%), and uveitis (2.7%).	Air descemetopexy is effective

Surgical intervention comprises

1. Intracameral gas injection (non-expansile) (C₃F₈ 14% or SF₆ 20% injection) or sterile air injection: 14% C₃F₈ is prepared by taking 0.14 mL of 100% C₃F₈ and diluting it to 1 mL.

2. Descemetopexy with sutures.

1. Conservative Medical Management:

   Medical management is indicated in small, peripheral, planar DMD with non-scrolled edges, in young patients. DMD of height <100 mm and limited to a small area will resolve with conservative medical management.[48] The conservative therapy includes topical steroids and hyperosmotic agents (hypertonic saline 5% drops and 6% ointment). Topical steroids (prednisolone acetate 1% eye drops) help in controlling inflammation and reduce the risk of developing DM fibrosis and scarring. Hypertonic saline eye drops imbibe fluid from the corneal stroma and help dehydrate the cornea. This improves the vision transiently. Medical therapy was noted to be successful in 96.9% in a prospective evaluation of 116 cases of DMD, in comparison to surgical treatment.[48] Eyes with DMD persisting for more than 4 weeks have been recommended to be considered for surgical intervention.

2. Surgical:

   Surgical intervention modalities described in the management of DMD include:[8]

   1. Descemetopexy with air/gas (SF₆/C₃F₈)/with or without sutures

   2. Mechanical tamponade with intracameral sodium hyaluronate

   3. Manual reposition

   4. Descemetotomy

   5. Interface fluid drainage

   6. Endothelial keratoplasty – DSEK/DSAEK or DMEK procedure.

Descemetopexy

Sparks et al.[58] in 1967 first described the reattachment of DMD with the injection of air in the anterior chamber in three eyes following cataract surgery. In another study, the efficacy of air alone was notably better when a complete air fill was targeted in the anterior chamber and supine positioning was maintained after the surgery similar to the practice in endothelial keratoplasty. The air/gas injection technique involves locating the limbal site where the cornea is relatively compact and the DM appears apposed, or at least close to the posterior stroma. A 29-gauge needle with the bevel down or a cannula through a side port is introduced to reach beneath the plane of the detached DM, and slow injection of air/gas is attempted to achieve a firm tamponade of the DM. While withdrawing the needle or the cannula, care is taken to prevent air escape from the anterior chamber.[55] Complete air fill of 30–60 seconds is desirable. In eyes with poor visualization of the anterior chamber, an endo illuminator can be used to determine the orientation of the DM. Intraoperative OCT, if available, can also help in ascertaining the correct plane of performing air/gas injection.[59] The rapid absorption of air and the need for retention of tamponade for an extended period led to the concept of using iso-expansile gases, such as 2%–14% C3F8 [Fig. 3] and 14%–20% SF6, which would remain in the anterior chamber, providing an effective tamponade for 6–8 weeks and 2 weeks, respectively. Repeat descemetopexy has been recommended before considering keratoplasty.[56] Viscoelastics[60] and mattress sutures have been used to aid in the fixation of the detached DM to the posterior cornea along with using air.[61]

Figure 3.

(a) Post-small-incision cataract surgery DMD, 1-month postop, showing edema (b) Postoperative day one after C3F8 injection, clearing of edema seen

Indications for preferring the use of gases over air include[62,63,64]

1. Inferior non-planar (>1 mm difference between the DM and stroma) DMD

2. Superior DMD with scrolled edges

3. Central planar or non-planar DMD

4. Long-standing DMD

5. Taut DMDs following fibrosis and inflammation.

Pros of using gas over air are that it does not need repeated injections and stays in the anterior chamber for a longer time till endothelium is functional. However, raised intraocular pressure and pupillary block glaucoma are risk factors, and endothelial dysfunction has been reported in animal studies.[65,66]

A retrospective study of 112 cases of DMD by Odayappan et al.[8] reported a 71% success rate with only intracameral air injection. In this series, 15 cases required re-surgery, of which 60% were successfully reattached. One patient with persistent edema underwent endothelial keratoplasty. Appositional angle closure (18%), pupillary block (2.1%), and uveitis (2.7%) were the complications noted.

Jain et al.[45] recommended descemetopexy with air over C3F8. Garg et al.[57] used C3F8 and concluded that the location and extent of DMD did not influence prognosis, but the type of detachment did - planar detachments had a higher success rate as compared to non-planar ones. Sharma et al. recently described the use of “two bubbles” - using a smaller gas bubble to unroll the DM and using a larger bubble for tamponade.[67] Li F et al.[68] described an outpatient descemetopexy on slit lamp with the help of Pentacam and AS-OCT, followed by an immediate supine position. Chow JY et al.[69] used a lower concentration (10%) of C3F8 in a patient successfully, with the advantage of lesser IOP rise.

Suture fixation

Suture fixation is recommended once the air/gas descemetopexy fails. Vastine et al.[70] used it in a case series. Sutures were particularly useful to unroll scrolled DM, which only gas/air descemetopexy could not attach. Suture fixation helps prevent redetachment.[71]

Full-thickness, interrupted sutures are passed at several places to attach the DM.[72] Trans corneal suture fixation with 10-0 monofilament nylon suture may be combined with gas or air descemetopexy in the management of DMDs.[72,73] This is useful in cases of

• 1)Large DMD
• 2)Recurrent DMD with primary pathology of the cornea
• 3)Intractable DMD in post-cataract surgery patients
• 4)In cases of complicated cataract surgery that are associated with intraoperative complications such as posterior capsular rupture, dislocated IOL, aphakia, zonular dialysis, etc.

With the help of suture fixation, large peripheral DMD can be easily managed. It avoids risk of pupillary block, and even if combined with air/gas descemetopexy, the whole anterior chamber need not be filled. However, there is a risk of suture-related infection and endophthalmitis. It may induce astigmatism and tenting of the DM. Mere suture fixation is unlikely to resolve large, central DMD, and the outcome could be variable.

Manual repositioning

Manual repositioning of DMD is not advisable due to the associated risk of injury to endothelial cells. This procedure has been described for unscrolling the edges of taut DMD with the iris spatula and cyclodialysis spatula followed by injection of air/gas.[58,74]

Descemetotomy

Descemetotomy is the opening up of the retained DM to allow passage of the aqueous. Loewenstein et al.[75] described descemetotomy in 1993 in post-keratoplasty eyes with retained host DM. Descemetotomy can be achieved with either the surgical removal of the membrane or the creation of a break in the host DM with the help of an Nd-YAG laser.

Interface fluid drainage

Drainage of interface fluid between the DM and stroma is done using a 20-gauge micro-vitreoretinal blade, 23-gauge needle, and curved needle of 10-0 monofilament suture for drainage. The success in drainage of interface fluid can be monitored and confirmed intraoperatively with intraoperative microscope-integrated OCT.[76]

Intraoperative OCT-assisted descemetopexy with stromal vent incisions (to allow for the egress of large fluid collection between the detached DM and posterior stroma) along with intracameral gas injection helps in the resolution in cases of non-resolving DMD.[59]

Bhatia and Gupta[77] used gas descemetopexy but could settle the DM once it was combined with venting incisions. Another group combined supra Descemetic venting incisions with gas descemetopexy. Adding venting incisions can help to increase the success of descemetopexy.[78] A study from Iran described the drainage of supradescemetic fluid through a 10-0 needle with air injection in the anterior chamber to settle DMD.[79]

Descemet stripping only

Stripping the DM and not replacing it could be an alternative to endothelial keratoplasty in Fuchs with relatively healthy peripheral endothelium[80] or post complicated surgery.[81] Coiled edges do not let attachment of the DM with mere descemetopexy, and DM stripping only combined with netarsudil eye drops can clear the cornea.[82]

Endothelial Keratoplasty for DMD

Keratoplasty is one last option for the management of DMD. Endothelial keratoplasty can be considered once even repeat descemetopexy has failed.[56] In this study, the failed case post repeat descemtopexy had a taut, stretched DM, which needed endothelial transplantation. Cases where corneal scarring has not set in yet can be rehabilitated with endothelial transplantation. Odayappan et al.[8] reported that 7.3% of cases needed endothelial transplantation post failure of pneumatic descemtopexy. Large DM tears or DM loss led to the failure of descemetopexy. Although air/gas decemetopexy is the first surgical choice of treatment, it will not suffice in all cases.

Descemet's stripping automated endothelial keratoplasty (DSAEK)

DSAEK is considered in cases of DMD with damaged endothelium and enables visual improvement.

DSAEK can provide a successful outcome in patients with large DM loss and stretched-out DM after intraocular surgery.[56] Successful DSAEK has been tried post cataract surgery DMD[8,46] and post keratoplasty DMD.[31]

Descemet Membrane Endothelial Keratoplasty (DMEK)

DMEK, performed early in cases of DMD, serves to enable rapid recovery with better visual and refractive outcomes. DMEK is indicated in cases with scarred and taut DM, failed descemetotomies, and recurrent DMD with progressive corneal decompensation.

Conclusion

DMD is an ocular emergency, usually following intraocular surgery. Older age, pre-existing endothelial dysfunction such as Fuchs dystrophy, blunt instruments, and poor surgical technique increase the risk of DMD. Small, planar detachments away from the visual axis can be managed medically, but larger ones need surgical intervention, particularly if the edges are scrolled. Air/gas descemetopexy is the first step for surgical management and it suffices in over 70% of cases. Larger detachments may need suture fixation. Scrolled edges, DM defects, or very large tears might ultimately need endothelial transplantation or even full-thickness keratoplasty. A step-wise approach is important.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.