This is a 43-year-old patient who came in 1965 for irritation and redness in his right eye (RE) for 1 month. He had been doing treatment with atropine, aureomycin and epithelializing ointments. In the last days he began to have more pain and noticed the appearance of a white spot "in the pupil". The left eye was healthy.

The visual acuity (VA) upon arrival was in the RE of hand movement, with good light perception and location. There was a marked conjunctival and ciliary hyperemia, and a creamy white opacity that occupied the central area of ​​the cornea in about 5 mm, of rounded shape and with not very net edges. On it there was an epithelial defect and the most peripheral cornea was somewhat edematous. The anterior chamber was well formed and showed some hyperemia of the iris, as well as a curved upper edge hypopyon (Figure 1). A sample was taken from the edge of the abscess with a Desmarres’ knife, as well as from the aqueous humor through a paracentesis, followed by washing the anterior chamber with penicillin. Cultures of corneal abscess were positive for Candida albicans; those in aqueous humor were negative.

A therapeutic "hot" lamellar keratoplasty was indicated. A partial trepanation of 10 mm in diameter was performed, followed by a manual dissection in the corneal stroma as deep as possible, verifying that it had reached a level where there were no signs of infiltration. After washing the bed with penicillin and Neosporin, a corneal button of the same diameter was placed, trephined full-thickness from a donor eyeball to which the endothelium had been removed. This graft was fixed with 14 radial sutures of virgin silk of 7 filaments. After fixation, Neosporin was injected between the graft and the recipient bed.

The postoperative treatment included mydriatic eye drops, antibiotics and cortrophine 20 units/day, as well as oral mycostatin. The stitches were removed after 2 weeks. The postoperative evolution was very favorable. Although neovascularization appeared, it regressed after being treated with decadran eyedrops 4 times/day and several beta-therapy sessions. No systemic corticosteroids were used. At 6 months he reached a VA = 0.3 with correction (Figure 2), and in the last control, after 3 years, a VA = 0.7 with 80° -2.75 -5, and Nº 1 for near.

The graft was transparent, with no opacities visible on examination with diffuse light (Figure 3). There was a residual inflammatory membrane that followed the pupillary border in the lower sector. With the slit lamp we could distinguish a discreetly veiled interface and some very thin deep neovessels in the upper sectors (Figure 4).

COMMENT

"Hot" therapeutic keratoplasty is a resource that is usually reserved for situations in which an infection does not respond to medical treatment. In 1965, the availability of antifungals for ophthalmic use was almost non-existent. Perhaps this is why in this case the decision was made to intervene quickly in the face of the evidence of this etiology. In this situation, performing a deep lamellar keratoplasty has the advantage over penetrating of preserving the integrity of the eyeball and therefore avoiding the risk of surgery spreading the infection, apart from the respect for the endothelium of the recipient. The main drawback was the doubt about whether lamellar resection was going to eliminate all the infected tissue, so it was tried to be as deep as possible within the possibilities of a manual dissection. The result was surprisingly good even in functional terms since the experience at the time in these circumstances made us expect at most the cure of the infection and a reconstructive result with limited vision.

In the processes of corneal lysis, the stroma is digested by the action of collagenases released by activated keratocytes. Depending on the severity of the case, the degree of inflammation and the treatment, the loss of the entire thickness in the area of ​​the ulcer may occur and the Descemet’s membrane (DM) may be exposed, an entity known as descemetocele. Since DM is more resistant than stroma to collagenases, it can be maintained for some time without perforation.

The patient in question was 63 years old and had a history of herpetic keratitis that evolved to neurotrophic. He came with a paracentral descemetocele of around 1.5 mm (Figure 1). We decided to perform a deep anterior lamellar keratoplasty (DALK) for tectonic purposes.

The surgery begins with a partial thickness trephination in the receiver. Since neurotrophic ulcers are usually central or paracentral, trepanation will completely include the area of ​​the ulcer and should be approximately 2/3 of the corneal thickness in its perimeter (Figure 2).

Next, we resect the previous 2/3 of the stroma by lamellar dissection with a knife (Figure 3). Before manipulating DM, it is advisable to perform a paracentesis to cause hypotonia, which reduces the risk of rupture of the same.

We proceed to carefully look for the plane of separation between the posterior stroma and the DM, tapping with a spatula or a blunt cannula at the edge of the ulceration (Figure 4A). Once we find the plane, we should gradually separate the posterior stroma and DM in the 360​​° of the tissue adjacent to the ulcer, with a flat-tipped and blunt spatula (Figures 4B and 4C).

To complete the dissection up to the height of trepanation, we use a viscoelastic injection. The passage of this between the stroma and the DM forms a wave that allows us to visualize the limit of the dissection (Figure 5A). Once this is achieved, we can carefully remove the remaining stroma similar to the resection of the "big bubble" ceiling, e.g. by division into 4 quadrants with corneal scissors (Figures 5B and 5C). Once the DM of the recipient is completely exposed, we must completely eliminate the viscoelastic remains by means of a careful irrigation, to avoid the formation of a double anterior chamber in the postoperative period.

The surgery ends with the application and suture of a full thickness graft (Figure 6), from which DM and endothelium have been previously extracted. The patient evolved favorably. The presence of a descemetocele is not a contraindication to perform a DALK^1,2. The opening of the space between the deep stroma and the DM from the edge of the ulcer can be relatively simple with the help of viscoelastic, as in the case presented, possibly due to the effect of the collagenases. However, locating this plane is more difficult in the early phases of the descemetocele and, especially, when there are still some lamellae of stromal tissue on the DM.

This is a 54-year-old patient who had suffered a chemical burn on her right eye (RE) 5 years ago. In the exploration she had a visual acuity (VA) of hand movement. The left eye (LE) was undamaged (VA = 1). The RE presented a total limbal insufficiency, with opacification and vascularization of the corneal surface (Figure 1). To achieve a recovery of the corneal epithelium, a limbal autograft was proposed, which was performed under general anesthesia according to the technique described by Kenyon and Tseng¹, taking two sectors, upper and lower limbs from the LE and implanting them in the RE (Figure 2).

After 20 days, complete epithelization was achieved, and in the following weeks there was a partial clearance of the corneal transparency (Figure 3), reaching a corrected VA = 0.2. However, the cornea still has a leucomatous appearance with some thin areas and superficial neovessels in the upper sector (Figure 4). Therefore, she was proposed to perform a cornea transplant. The patient accepts and, under local anesthesia, a deep anterior lamellar keratoplasty (DALK) is performed. The dissection technique chosen was that of the big bubble of Anwar and it was possible to reach the descemetic plane.

The study by optical coherence tomography (OCT) allows to appreciate the correct apposition of the graft and the absence of residual stromal bed (Figure 5). The evolution was favorable, and this eye reached, 2 years after grafting, a corrected VA = 0.9 (Figures 6 and 7).

COMMENT

Most of the postoperative complications of corneal transplants are due to problems resulting from an insufficient limbus. Before proposing any keratoplasty technique, we must study the state of the limbus, which has a double mission: it contains the stem cells responsible for the production of a healthy corneal epithelium and acts as a barrier to prevent the invasion of the conjunctiva on the cornea. In the slit lamp, the presence of pannus is an indicator of the loss of said barrier function; recurrent epitheliopathy and corneal ulceration are signs of limbal cell failure. There are more sophisticated diagnostic methods such as impression cytology, in which goblet cells are seen on the corneal surface, or Limbotest (Bioftalmik Applied Research) that detects the MUC-5 mucoprotein on the corneal surface, in cases of limbal incompetence.

The existence of a diseased limbus predisposes to a poor graft evolution, either due to problems of epithelialization – persistent epithelial defect, corneal melting, perforation – or to favoring the appearance of a rejection in cases with neovascularization. Before proceeding to a transplant, we must treat the limbal insufficiency, depending on whether it is partial or total. In cases of partial deficit, we have several options such as the use of lubricants, sequential sectorial conjunctival epitheliectomy², autologous serum and other plasma derivatives, and amniotic membrane grafting. Faced with total insufficiency, we will have to provide a new limbus, either by limbal autograft if the other eye is healthy or an allograft – from a cadaver donor or a compatible living donor – in bilateral cases. In the latter situation, cells expanded in culture, whether limbal or from oral mucosa, can also be used³.

The existence of neovessels in the recipient cornea is the main factor for the appearance of a rejection, so they must be treated before or simultaneously to the transplant. Monopolar coagulation, photodynamic therapy and the use of antiangiogenic agents⁴ are the most effective methods. In cases in which we do not have a healthy limbus and the measures described above have not been effective, a corneal graft will be doomed to failure and as an alternative we should consider a keratoprosthesis.

A 37-year-old male patient with a history of myopia of about 5 diopters in both eyes, underwent bilateral LASIK surgery in 2003. According to his report, 2 years later he started a decrease in vision with increased astigmatism in the right eye (RE). A topographic study indicated the presence of corneal ectasia in that eye. Due to the progressive worsening, in 2006 he was operated on with implant of intracorneal ring segments (SAIC); they achieved topographic improvement but not visual improvement. In the following months the RE continued to worsen and in 2008 he started a corneal ectasia in the left (LE), which was treated by corneal crosslinking.

In 2009 he was referred to our center to assess a possible keratoplasty in the RE. At that time, the best corrected visual acuity (BCVA) was in the RE = 0.2 (60° -5.00 -8.00) and in LE = 0.9 (125° -3.50 -0.75). The RE presented a corneal ectasia with significant irregular astigmatism. The RE was operated on with deep anterior lamellar keratoplasty (DALK), with explant of the SAIC and big bubble technique. The recipient cornea was trephined at 8.25 mm and that of the donor at 8.75 mm.

The surgery was carried out without incidents and a complete dissection was achieved up to the predescemetic layer of Dua (PDL), integrated with the Descemet membrane (DM). However, in the postoperative examination of the first day, a fine but complete separation was observed between the receiving DM/PDL and the posterior surface of the graft, without mobility (Figure 1). Optical coherence tomography (OCT) examination confirmed that the DM/PDL of the receiver was extended, almost parallel to the donor stroma (Figure 2).

We followed the patient and, since after one month he had not improved, we performed a reformation of the anterior chamber with air in the operating room. There was no improvement and one month later we decided to check the graft in the surgical theatre, with the suspicion of viscoelastic remains trapped in the interface. After extracting the sutures in the upper quadrant, we lifted the graft without observing any presence or viscoelastic output. We refilled again the anterior chamber with air through a paracentesis.

The result was the same as on the previous occasion, with no improvement observed. We decided to wait to avoid possible iatrogenia to the endothelium with the repeated injections. One month later (3 months after surgery) we observed how the receiving DM/PDL began to contact the donor stroma in the temporal and nasal periphery.

After another month, the entire central area was in contact (Figure 3) and 7 months after the original intervention (July 2010), the DM/PDL was almost completely adhered to the donor corneal button (Figure 4).

One year after surgery and after extraction of the sutures, the RE reached a BCVA = 0.9 (20° -1,75 -8,00). The LE remained stable refractive and topographically. This refractive defect of the RE, which caused anisometropia, was corrected by implanting a phakic intraocular lens in the posterior chamber. The cause of this type of smooth separation of DM/PDL in the absence of perforation has not been clarified. In the absence of evidence, in this case, that viscoelastic persists at the interface, it is possible to invoke a possible disparity of curvatures between graft and receiver, as proposed by Sarnicola (see chapter 5.6.2).

This is a 72-year-old male patient who had several episodes of stromal herpetic keratitis in his right eye (RE). He reported not having recurrence for more than 3 years. His visual acuity with correction (BCVA) was 0.1 in RE and 0.8 in the left eye. He had a vascularized paracentral corneal leucoma, which affected the anterior and posterior stroma, although it did not seem to affect the plane of the endothelium (Figure 1).

The area of ​​the leucoma was somewhat thinned – 460 μm at its thinnest point. Lacrimal function and corneal sensitivity were normal. Two intrastromal injections of bevacizumab had failed to reduce neovascularization. We started 200 mg of oral acyclovir for one month prior to surgery.

We proceeded to perform deep anterior lamellar keratoplasty (DALK) by the "big bubble" method (BB) (video 5.8.5.1). We always perform a partial anterior keratectomy, which facilitates both the injection of air into the posterior stroma and the resection of the roof of the BB. We use a single-use suction trephine, in this case 8.5 mm. The trepanation is partial, between 5 and 6 quarters of turn that correspond to 350-400 μm. To dissect the anterior lamina, we use a semilunar knife with horizontal movements. For pneumo-dissection we use a round blunt spatula of Sarnicola and a cannula of John of 27 G with three holes.

In this case, two BBs were formed: a small and central type 1 and another somewhat deeper, eccentric and of thin edge or BB type 2. When puncturing the roof of the first both collapsed, but, inadvertently, we only dissected the first. This did not reach the margin of the keratectomy and the dissection had to be extended manually. BB type 1 was small because the air, trying to expand more, produced a pore in the predescemetic layer of Dua (PDL) – surely damaged in the area of ​​the leucoma – and thus passed between it and Descemet’s membrane (DM) creating the second bubble of type 2. This type of mixed BB is known as "BB type 3" (see chapter 5.2) and has been observed more frequently in corneas with stromal fibrosis, as was this case. After exposing the "floor" of the first BB, an 8.75 mm graft was placed and sutured, previously trephined and its DM/endothelium extracted.

The problem was that during the surgery we did not appreciate that there was still a second bubble. In the immediate postoperative period, an anterior double chamber image was observed (Figure 2), which in optical coherence tomography (OCT) images revealed to be actually triple: in them we can distinguish the floor of the first BB corresponding to PDL, with some residual stroma in some peripheral area, because the dissection was finished manually. The floor of the second BB can also be observed, which corresponds to the DM/endothelium complex, and is also wavier and extends to the periphery (Figure 3).

After two days we lifted the graft to check the interface. We located the small hole and identified the BB type 2 by filling it with viscoelastic, then emptied it by means of a bubble of air in the anterior chamber at a certain pressure and dried the interface to check the reapplication of DM and PDL. The graft was sutured again, and the anterior chamber was pressurized again with air, which after a graft massage to favor further coaptation, we left filled in 2/3. The patient remained in supine for 24 hours. However, when examining it again, a fine separation persisted, which the OCT showed it still affected the three levels (Figure 4).

We injected air again in the consultation and finally achieved the application of the two membranes to the graft (Figure 5). It could be asked if this persistence of the separation was due to viscoelastic remains. But in any case, it seems to confirm that this type of smooth detachment has a good prognosis in general.

A 75-year-old woman with a history of type 2 diabetes mellitus and smoking, treated for progressive corneal opacity with topical corticosteroids for 11 years. The visual acuity was of light perception in both eyes. The bio microscopy showed in the right eye (RE) a dense corneal opacity of lipoid aspect, with a creamy white color and feathery edges. It occupied the cornea diffusely from the periphery and with inferior predominance. It respected a small central area that allowed to see a nuclear cataract (Figure 1). In the left (LE), pseudophakic, there was a similar opacity of predominance in the temporal periphery and some superior neovessels (Figure 2). The intraocular pressure (IOP) was 17 and 20 mmHg, respectively. The ocular ultrasound indicated in the LE a possible sub-hyaloid hemorrhage and vitreous hemorrhage, but in the RE it did not show alterations. The lipid profile in blood was normal.

Faced with this situation, we judged that the possibility of recovering a certain vision depended in the first place on restoring the corneal transparency of the RE, which was better on ultrasound than the LE. For this, we programmed a deep anterior lamellar keratoplasty (DALK). Under retrobulbar anesthesia, we performed a partial trepanation with Hanna's trephine at 400 μm and 7.75 mm. Due to the lack of visibility that prevented the technique of the big bubble, we opted for a manual dissection with semilunar knife and spatulas (Duckworth & Kent/Asico, 6-607).

Upon reaching the deep stroma, however, we appreciated a space through which the Descemet’s membrane (DM) could be easily accessed. This detached without difficulty, as if the lipoid deposit compacted all the stroma in block, which we could cut with scissors (Figure 3, video 5.8.6.1). The examination of the back of the eye revealed pre-papillary and sub-hyaloid hemorrhages at this time. Suturing the full-thickness graft without endothelium completed the surgery.

Despite the fact that corneal surgery was uneventful, on the third day there was a detachment of DM, narrowing of the anterior chamber (AC) and hyphema, with IOP = 24 mm Hg (Figure 4). We found that the cataract was dense. After establishing hypotensive treatment, air injection in AC and positioning was performed without result. Faced with the suspicion of phacogenic glaucoma, on the 6^th day after DALK we performed a triple procedure of penetrating keratoplasty, cataract extraction and intraocular lens implantation (IOL) (Figure 5).

The patient recovered a VA of counting fingers at 50 cm one month after surgery. In spite of the good result of the anterior segment surgery, the patient refused to continue with the treatment of her proliferative diabetic retinopathy.

COMMENT

The most frequent cause of lipoid deposits in the cornea is secondary to extravasation of triglycerides and cholesterol from neovessels developed during inflammatory processes. They usually affect only one eye, although there are bilateral cases such as the present one, sometimes of idiopathic origin¹. In some corneal dystrophies such as Schnyder's or the deep and annular crystalline², the lipoid deposits are presented with a familial pattern and affect both corneas, also in a diffuse and progressive way³.

In this case there was no apparent cause for bilateral lipoid keratopathy, perhaps related to his diabetes although no dyslipoproteinemia was found. Despite using a manual technique, the plane of the DM separated cleanly upon reaching it. This lack of fibrosis and adhesions in the deep stroma is not common in inflammatory corneal pathology and indicates that the massive lipoid deposit would have occurred in the absence of significant inflammation, perhaps due to an alteration in the metabolism of keratocytes⁴. In any case, the presence of these deposits would facilitate dissection for a DALK, although it can also be associated with postoperative complications such as those that occurred in this patient.

We present the case of a 56-year-old patient with late ectasia in penetrating keratoplasty (PK) for keratoconus. When she came for the first time in 1993, the visual acuities (VA) were: right eye (RE) = lumps, does not improve with correction; left eye (LE) = finger count, with 110° -4 -1 reaches 0.5. Keratometry (KM): RE difficult to measure, approximately > 60 diopters (D) at 160° and 60 D at 70°; LE = 50 D at 128° and 48 D at 38°. Intraocular pressure = 15 mmHg in BE. He was indicated PK (8 mm) in RE, which was done in April of the same year with favorable result. At 8 months, she had VA with correction (BCVA) = 0.85 (with 140° -6). KM was 46 D at 140°, and 40 D at 50°.

She returned in August 2008 with a transparent "crystal" graft, but incipient ectasia of the superior graft-host junction. In December 2011 her BCVA was RE = 0.3 (85° -6 +0.5); LE = 0.8 (115° -2.75 -3.25). In September 2013 a progression of the ectasia was observed, both superior and inferior, with KM RE = 52 D at 5° and 39 D at 95° (13 D of astigmatism against the rule). The graft remained transparent (Figure 1). Peripheral ring lamellar keratoplasty (PALK) performed in February 2014 was indicated.

The intervention (video 5.8.7.1) started by marking with a knife a groove that follows the graft-recipient scar. With a 12 mm manual trepan, we perform a concentric partial trepanning, which coincides approximately with the limbus. With another 8 mm we deepen the first mark to a medium depth, taking care not to perforate (Figure 2).

We dissect with a knife the peripheral cornea ring in 360° between the two trepanations, following a deep plane (Figure 3). The resection of this ring is completed with scissors and the edges are regularized. With a semilunar knife the deep plane extends 1 mm outside the main trephination, to facilitate the passage of the sutures (Figure 4).

We applied a new ring graft, trephined with the same diameters, full thickness and without endothelium (Figure 5). We sutured it with independent 10-0 nylon sutures, given so that the knot is directly buried, and finally we placed a therapeutic contact lens (Figure 6).

The postoperative evolution was satisfactory and a year and a half later (June 2015) the RE presented a transparent graft (Figure 7, video 5.8.7.2) with BCVA = 0.6 (60° -3 -2.5), with an evolving cataract. The LE remains stable, without progression of its incipient keratoconus.

COMMENT

To date, late ectasias in patients with keratoconus operated on for penetrating keratoplasty (PK) are becoming an increasingly frequent pathology in the corneal pathology reference ophthalmological centres^1,2. Although localized ectasias can be corrected with a wedge resection³, when they affect a large part of the corneal periphery, they represent a more complex problem. In some cases, we have corrected them with a full-thickness lamellar keratoplasty on the PK. However, we currently prefer reconstruction by means of peripheral annular lamellar keratoplasty, in order to respect as much as possible the old central graft when this is transparent.