Immunologic Graft Reactions Research Articles

Descemet Membrane Endothelial Keratoplasty in Children

To describe the outcomes of Descemet membrane endothelial keratoplasty (DMEK) performed in amblyopic aged (younger than 8 years) children. This is a single-center retrospective study, including 11 eyes (7 congenital hereditary endothelial dystrophy and 4 congenital glaucoma) of 6 children in amblyopic age undergoing DMEK by a single surgeon (N.C.P.) at Sorocaba Eye Hospital from December 2015 to November 2017. Best spectacle-corrected visual acuity, biomicroscopy, pachymetry, endothelial cell density, and complications were evaluated. No intraoperative complications occurred. Graft detachment occurred in 1 eye (9.1%) and was successfully managed with rebubbling. No primary graft failure or pupillary block was observed. All pachymetric measurements improved, and the corneal edema clinically resolved in all eyes within 2 weeks after the procedure. At the last follow-up (mean 30 months), best spectacle-corrected visual acuity was ≥20/40 in 7 (77.8%) of 9 eyes from patients cooperative enough to assess vision. All children began visual stimulation therapy and amblyopic treatment within 1 month of surgery, and all grafts remained clear until the last follow-up. The mean preoperative donor endothelial cell density was 2588 ± 236 cells/mm, which decreased to 1726 ± 292 cells/mm 2 years after surgery, yielding a 33% reduction (P < 0.001). No immunologic graft reaction, secondary graft failure, or cataracts were observed during the follow-up period. In this series, DMEK was performed to successfully treat endothelial dysfunction in children. However, the procedure is more challenging, and more studies with more patients and longer follow-up are needed to confirm the superiority of DMEK in treating endothelial dysfunction in children.

Evaluation of Phacoemulsification Cataract Surgery Outcomes After Penetrating Keratoplasty.

BACKGROUND:Cataract is one of the reasons which causes impaired visual acuity (VA) of the eyes after penetrating keratoplasy (PK), which can be treated by cataract surgery after PK or triple procedure. Cataract surgery after PK has advantages that parameters of the eyes such as axial length, anterior chamber depth (ACD) as well as corneal curvature are stabilized after removing all sutures postoperatively, and intraocular lens (IOL) power can be calculated correctly. Therefore, postoperative VA will be improved significantly. In Vietnam, there have not been any study about cataract surgery after PK, therefore we conduct this research.AIM:To evaluate the outcomes of phacoemulsification cataract surgery following primary PK.METHODS:Non-randomized controlled intervention study. Ninteen eyes (19 patients) that underwent phacoemulsification plus IOL insertion after initial PK in Cornea department, Vietnam National Institute of Ophthalmology, from December 2013 to September 2014.RESULTS:All patients presented with reduced VA, including 17 eyes (89.9%) with VA ≤ 20/200, mean astigmatism was 7.9 ± 1.0 D. Clear corneal grafts in 16 eyes while corneal opacity was seen in 3 eyes. All eyes with cataract were diagnosed from grade 2. After cataract surgery, improved VA > 20/200 was achieved in 72.22% of cases. There was a markable reduce of postoperative astigmatism with 1.8 ± 0.8 D (p < 0.05). However, the immunologic graft reaction was presented in one eye, and two edematous corneas also reported after cataract surgery. After treatment, there was one cornea achieved its clarity.CONCLUSION:Phacoemulsification cataract surgery following initial PK showed good outcomes with improved postoperative VA, reduced astigmatism, and the ultimate graft survival rate was high.

Descemet membrane endothelial keratoplasty for graft failure following penetrating keratoplasty.

Descemet membrane endothelial keratoplasty (DMEK) is superior to penetrating keratoplasty (PK) in terms of visual rehabilitation, intraoperative safety and risk of rejection. Therefore, it seems reasonable to perform DMEK in eyes with endothelial failure following PK. We herein report our first clinical results. Nineteen eyes with endothelial graft failure following PK were treated with DMEK. The majority of these eyes (12) had limited visual potential. The major indication for DMEK was pain relief in patients with bullous keratopathy. Visual acuity (VA), central corneal thickness (CCT), rate of graft dislocations, graft survival, graft rejections and other complications were extracted from the medical records. Although comorbidities limiting VA were present in 12 of the 19 eyes, VA increased from 0.05 to 0.1 (median) in 16 eyes. CCT decreased substantially (range 63-363μm). Rebubbling was necessary in five eyes with incomplete graft adherence. There were two immunologic graft reactions and three graft failures. No major complications like endophthalmitis or expulsive bleeding occurred. DMEK is feasible to treat endothelial graft failure following PK. This is even true for eyes with limited visual potential.

Evolution of Endothelial Keratoplasty

Endothelial keratoplasty has evolved into a popular alternative to penetrating keratoplasty (PK) for the treatment of endothelial dysfunction. Although the earliest iterations were challenging and were not widely adopted, the iteration known as Descemet stripping endothelial keratoplasty (DSEK) has gained widespread acceptance. DSEK combines a simplified technique for stripping dysfunctional endothelium from the host cornea and microkeratome dissection of the donor tissue, a step now commonly completed in advance by eye bank technicians. Studies show that a newer endothelial keratoplasty iteration, known as Descemet membrane endothelial keratoplasty (DMEK), provides an even faster and better visual recovery than DSEK does. In addition, DMEK significantly reduces the risk of immunologic graft rejection episodes compared with that in DSEK or in PK. Although the DMEK donor tissue, consisting of the bare endothelium and Descemet membrane without any stroma, is more challenging to prepare and position in the recipient eye, recent improvements in instrumentation and surgical techniques are increasing the ease and the reliability of the procedure. DSEK successfully mitigates 2 of the main liabilities of PK: ocular surface complications and structural problems (including induced astigmatism and perpetually weak wounds), whereas DMEK further mitigates the 2 principal remaining liabilities of PK: immunologic graft reactions and secondary glaucoma from prolonged topical corticosteroid use.

Amniotic Membrane Transplantation for the Treatment of Infectious Ulcerative Keratitis Before Elective Penetrating Keratoplasty

Emergency keratoplasties for inflamed eyes are considered to have a worse prognosis because of immunologic graft rejection. Amniotic membranes have antiinflammatory and antiangiogenic abilities. Therefore, amniotic membrane transplantation (AMT) was performed to stabilize the situation of eyes with severe infectious keratitis before elective penetrating keratoplasty (PK). Retrospective, nonrandomized observational case series. Seven to 41 days (median, 20 days) after the onset of intensive antiinfectious medication, an AMT (6 multigrafts and 6 sandwich) was performed in 12 patients [8 men and 4 women; age 46-80 years (median, 66 years)] with herpetic (n = 5), bacterial keratitis (n = 3), or combinations (n = 4). Three to 12 months (median, 5 months) after cessation of the inflammatory status of the eye, a central elective PK (diameter, 7-8 mm) became feasible in 10 eyes. Follow-up ranged from 4 to 38 months (median, 20 months) after PK. The primary success rate of AMT was 11/12 (92%). Five recurrences (41%) were treated successfully 4 times by repeat AMT (sandwich) and 1 time by emergency PK. In 2 of the 12 eyes, an irreversible endothelial immunologic graft reaction appeared 18 and 21 months after PK. One eye suffered from reversible recurrence of herpetic keratitis on the corneal graft. At the end of the follow-up, 10 of 12 grafts (83%) were clear. A rapid decrease in the inflammatory reaction and a fast reepithelialization because of AMT after intensive antiinfectious medication in case of severe ulcerative keratitis may help to avoid an emergency keratoplasty and improves the prognosis of the elective keratoplasty.

Immunologic graft reactions after allogenic penetrating keratoplasty

PURPOSE: To evaluate frequency and risk factors of immunologic graft reactions after allogenic penetrating keratoplasty. DESIGN: Interventional comparative nonrandomized clinical trial. METHODS: The setting took place in a university eye hospital. The retrospective study included 338 patients (338 eyes). The patients underwent penetrating keratoplasty performed by a single surgeon in the study period from 1989 to 1997. Follow-up period had to be longer than 12 months (mean ± SD, 31.4 ± 18.8 months). Frequency of immunologic graft reactions characterized by relatively few small monomorph whitish cells in the anterior chamber, almost no flare, and retrocorneal cellular precipitates. RESULTS: Immunologic graft reactions were detected in 46 patients (46/338 = 13.6%). Statistically significant risk factors for the development of graft reactions were loosening of sutures ( P = .046), and preoperative and postoperative corneal vascularization ( P = .04). Frequency of an immunologic graft reaction was statistically independent ( P > .05) of the graft diameters used in the present study, age, and gender of the patients, HLA-typing, donor age, and preservation data of the donor material. Seventy-four percent (34/46) of all graft reactions were detected within the first 2.5 years after surgery. Thirteen percent (6/46) of all graft reactions were observed more than 4 years after keratoplasty. With intensive corticosteroid treatment, graft transparency could be regained in 44 (95.6%) of the 46 patients with an immunologic graft reaction. CONCLUSIONS: Most important risk factors for immunologic graft reactions occurring in approximately 14% of patients after allogenic penetrating keratoplasty are suture loosening and preoperative and postoperative corneal vascularization. Graft diameters as used in the present study, HLA-typing, age of the donor, and preservation data of the donor material may not play a major role. More than 10% of graft reaction episodes can occur more than 4 years postgrafting. With intensive corticosteroid treatment, graft transparency can be regained in the majority of patients after an immunologic graft reaction when detected early.

Tectonic sclerokeratoplasty and tectonic penetrating keratoplasty as treatment for perforated or predescemetal corneal ulcers

PURPOSE: To report the clinical outcome of patients with perforated or predescemetal corneal ulcers treated by tectonic, centric or eccentric penetrating keratoplasty or by tectonic sclerokeratoplasty. DESIGN: Nonrandomized clinical trial. METHODS: The study included 60 patients (60 eyes) with perforated or predescemetal corneal ulcers who were consecutively operated on by the same surgeon. Fifty-two patients underwent tectonic penetrating centric or eccentric keratoplasty. Eight patients with paralimbal corneal ulcers underwent tectonic sclerokeratoplasty. A control group consisted of 76 patients (76 eyes) electively undergoing central penetrating keratoplasty for treatment of inactive central corneal scars. RESULTS: In the study group with perforated or predescemetal corneal ulcers, best-corrected postoperative visual acuity ranged from perception of light to 0.80 (median, 0.10), with 54 of 60 eyes (90%) attaining an improvement of best visual acuity. In 10 of 60 patients (16.7%), tectonic penetrating keratoplasty had to be re-performed because of a recurring corneal ulcer. Patients with sclerokeratoplasty and patients with eccentric keratoplasty did not differ in clinical outcome, despite larger trephine and corneal lesion size in the sclerokeratoplasty group. Among study patients compared with control patients, postoperative visual acuity was significantly lower ( P = .01), postoperative refractive and keratometric astigmatism were significantly higher ( P < .05), and immunologic graft reactions ( P = .02) and suture loosening ( P < .001) occurred significantly more often. CONCLUSIONS: Eyes with perforated corneal ulcers or predescemetal corneal ulcers can usually be saved by tectonic keratoplasty or sclerokeratoplasty, with a moderate to considerable amount of remaining useful vision. In case of doubt, one may prefer conservative treatment of corneal ulcers and to electively perform central keratoplasty when the ulcers have healed. For selected clinical situations, sclerokeratoplasty is an alternative to keratoplasty for surgical treatment of paralimbal corneal defects.

Intraocular pressure after homologous penetrating keratoplasty.

To evaluate intraocular pressure (IOP) changes after homologous central penetrating keratoplasty in a noncomparative interventional case series. The study included 245 patients undergoing homologous central penetrating keratoplasty for keratoconus (n = 77), herpetic corneal scars (n = 29), nonherpetic corneal scars (n = 46), Fuchs endothelial dystrophy (n = 24), and secondary corneal endothelial decompensation caused by preceding intraocular operations (n = 69). Mean follow-up time was 30.4 +/- 18.7 months (range, 12.1-111.6 months). The same surgeon operated on all patients, and a peripheral iridotomy was routinely performed. On the first postoperative day, IOP was significantly (P = 0.02) higher than that before keratoplasty. Taking the whole study group and taking the study groups separately, IOP measurements determined on the third postoperative day (P = 0.57), 1 week after surgery (P = 0.55), or later (P > 0.50) were not significantly different from the preoperative values. Eyes undergoing keratoplasty with cataract surgery and eyes undergoing keratoplasty without additional intraocular procedures did not vary significantly (P > 0.10) in IOP measurements. IOP did not differ significantly (P > 0.50) between eyes with an immunologic graft reaction (n = 29) and eyes without a reaction (n = 216). Acute angle-closure glaucoma was not detected in any of the patients. IOP measurements were statistically independent of suture type (P > 0.10), age (P > 0.05), preoperative and postoperative refractive error (P > 0.05), preoperative and postoperative corneal astigmatism (P > 0.10), preoperative and postoperative visual acuity (P > 0.10), diameter of graft and trephine (P > 0.15), and oversize of the graft (P > 0.50). Postoperative IOP measurements were significantly (P < 0.01) correlated with preoperative IOP values. In eyes with a peripheral iridotomy performed during surgery, homologous central penetrating keratoplasty usually does not markedly change IOP. The main risk factor for postoperatively increased IOP is increased IOP before surgery.

Immunologic transplant reactions after non-mechanical corneal trepanation with the excimer laser

Nonmechanical trephination has been established as the standard procedure in penetrating keratoplasty (PK) for avascular corneal diseases at our institution. The purpose of this study was to analyze the incidence and reversibility of immunologic graft reactions after nonmechanical trephination and to detect potentially causative factors. Out of a total series of 400 nonmechanical PKs, 286 consecutive procedures with sufficient follow-up performed between 07/1989 and 09/1997 were included in the study (104 x keratoconus, 78 x Fuchs' dystrophies, 31 x bullous keratopathies, 28 x ulcers, 25 x avascular scars, 12 x stromal dystrophies, 4 x buphthalmos, 4 x others; 202 x PK only, 84 x combined procedures; 276 first PK). The age of the 138 females and 148 males at the time of surgery ranged from 16 to 89 (mean 55 +/- 19) years. The recipient and donor trephinations were performed from the epithelial side using an 193-mm excimer laser (MEL50 or MEL60, Aesculap-Meditec, 1.5 x 1.5 mm spot mode, 16-24 mJ/pulse, repetition rate 30 or 25/s; metal masks). The shape of the recipient trephination was either circular with four or eight "orientation teeth" (n = 251; 5.0-8.0 mm diameter) or elliptical (n = 35, 6.0 x 7.0 to 7.5 x 8.5 mm diameter). In 62% of procedures fresh or short-term-preserved donor tissue was used, and in 38% of procedures the donor tissue was organ-culture-preserved. During a mean follow-up of 22 +/- 18 months (maximum 7.7 years), 10 acute diffuse (3 irreversible; 1.0%) and 3 chronic focal endothelial graft reactions occurred (4.5%) not earlier than 4 months and not later than 35 months after PK. Elective procedures (3.5%) resulted in significantly (P = 0.01) less reactions than acute corneal ulcers (14.3%). After 1, 2 and 3 years, the cumulative reaction rates (Kaplan-Meier values) were 1.3%, 6.3% and 13.9% in elective procedures, none of which, however, occurred after 26 elliptical trephinations. With fresh or short-term-preserved donor tissue (4.2%), graft reactions did not happen more frequently but earlier (12 +/- 6 months) than with organ-culture-preserved donor tissue (2.2%, 30 +/- 6 months). In patients with keratoconus (4.9%), reactions occurred more frequently (P = 0.05, LogRank) and earlier than in patients with Fuchs' dystrophy (1.3%). In addition to well-established optical advantages, nonmechanical trephination seems to have no immunologic drawbacks.

Excimer-Laser-193 nm-Trepanation bei der perforierenden Keratoplastik - Bericht über die ersten 70 Patienten

In penetrating keratoplasty, trephination with the 193 nm excimer laser may help avoid the differences in the deformation of the donor and recipient wound margins which occur with the conventional procedure. By varying the shape of the "open metal mask", other cut configurations can be achieved besides circular. Thus, "vertical tilt" and "horizontal torsion", both potential reasons for persistent long-term astigmatism after PK, may be minimized. Following experimental studies, the authors present the results obtained in their first 70 consecutive patients. 38 women and 32 men were treated (mean age 60.6 years, range 17 to 89 years). Indications were corneal processes without vascularization: Fuchs' dystrophy (n = 32), other stromal dystrophies (n = 5), secondary corneal endothelial decompensation (n = 6), keratoconus (n = 15), nonvascularized corneal scars (n = 4) and miscellaneous (n = 8 ). We used elliptical metal masks with/without orientation teeth and circular masks with four and eight orientation teeth, respectively. The HeNe aiming beam was manually controlled by a micromanipulator ("joystick"). The technical data of the laser were as follows: spot mode, 1.5 x 1.5 mm; repetition rate 30/sec and 25/sec, respectively; pulse energy 15-25 mJ; mean number of pulses 6407 (recipient) and 9150 (donor). With an elliptical outline, wound closure was usually achieved with single sutures. With a circular outline with orientation teeth, wound closure was most commonly achieved with a double running suture. Patients were prospectively documented using modified Erlangen record sheets. Follow-up ranged from 3 months to 3.4 years (mean 11.4 months). With two exceptions, penetration of the anterior chamber with the 193 nm excimer laser was accomplished without deformation of the cut edges. The elliptical outline facilitated fitting of the graft into the recipient wound bed, and the orientation teeth made fitting even easier. Initial intraoperative complications due to excessive laser energy densities included minor thermally induced corneal alterations caused by the heat of the metal mask and in a few cases minimal iris bleeding during corneal penetration. The median duration of re-epithelialization was two days. Wound healing was without complications. In particular, no primary graft insufficiency and no unexpected effects in donor or recipient corneas, iris, lens or posterior segments were observed. Postoperative complications were one corneal ulcer caused by premature fitting of an extended-wear contact lens and two immunologic graft reactions (3%). Mean astigmatism after suture removal was 4.6 D with an elliptical outline, and 3.9 D after trephination with orientation teeth and with the sutures in situ. Non-mechanical, "non-thermal" trephination with elliptical and circular metal masks with orientation teeth represents a viable alternative to knife trephination in penetrating keratoplasty. No unexpected complications such as disturbances of wound healing were seen. Further studies are needed to determine the effect on residual long-term astigmatism after suture removal.