Keratoplasty For Keratoconus Research Articles

Late corneal ectasia after penetrating and deep anterior lamellar keratoplasty for keratoconus.

To investigate tomographic features of late corneal ectasia after keratoplasty for keratoconus and compare penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK) in terms of incidence, time of onset and risk factors of corneal ectasia. Sixty eyes with PK and 30 eyes with DALK operated between 1999 and 2021 were analyzed. Final Pentacam scans were evaluated together with vision and previous topographies. Main outcome measures were vision, K values, apparent thinning on graft-host cornea and the difference between opposing quadrants in the thinnest point measurements. Anterior segment optic coherence tomography was performed for further evaluation. Mean follow-up was 127.2mo (24-282mo) in PK, and 64.3mo (24-144mo) in DALK. K max was higher in DALK (60.6 vs 56.7 D, P=0.012). Inferior recipient was thinner (595.9 µm) in PK than DALK (662.2 µm, P=0.021), due to longer follow-up. Overall corneal ectasia rate was 20.0% within 24y. Ectasia rate was the same (6.7%) in DALK 2/30 and in PK 4/60 in 10y and 13.3% in 12y (4/30 and 8/60, respectively). It increased to 23.3% (14/60) in PK over 24y. While ectasia was not seen before 7y in PK, it could be seen in DALK starting from the 5th year. The intervals between keratoplasty and ectasia were 144.5mo in PK and 99mo in DALK. Inferior recipient was significantly thinner in 18 eyes with ectasia (502.7 µm) compared to 76 non-ectasia (649.1 µm, P=0.000). Inferior graft was thinner (561.0 vs 620.4 µm, P=0.006), K max (63.3 vs 56.5 D, P=0.000), and anterior elevation was higher in ectasia (89.1 vs 48.6 µm, P=0.002). Accelerated crosslinking was performed on 5 eyes. Inferior-superior recipient and inferior graft thinning on tomography, with high K max and anterior elevation emerge as the most reliable criteria for the diagnosis of late ectasia. The incidence of corneal ectasia increases with the time.

Tomographic and topographic predictive factors of big bubble formation during deep anterior lamellar keratoplasty in keratoconus

PurposeTo identify preoperative predictors of big bubble (BB) formation during deep anterior lamellar keratoplasty (DALK) in patients with keratoconus (KC).MethodsDesignRetrospective cohort study in an Italian tertiary centre.Study populationConsecutive patients with...

Outcomes of Donor Corneas of Different Thicknesses From Endothelial Keratoplasty in Deep Anterior Lamellar Keratoplasty for Keratoconus.

To evaluate the outcomes of divided residual donor corneas obtained from endothelial keratoplasty in keratoconus with deep anterior lamellar keratoplasty (DALK). In this retrospective, comparative, clinical study, 103 keratoconic eyes that underwent DALK were enrolled; 67 eyes received thin grafts from Descemet stripping automated endothelial keratoplasty, and 36 received thick grafts from Descemet membrane endothelial keratoplasty. Baseline and postoperative central corneal thickness (CCT), inferior corneal thickness, uncorrected distance visual acuity, corrected distance visual acuity, corneal astigmatism, mean keratometry, biomechanical properties, and complication rates were measured. Six months after transplantation, the group receiving thin grafts had a CCT of only 455.1 ± 43.0 μm, whereas that of the group receiving thick grafts was 546.7 ± 44.2 μm. Both CCT and inferior corneal thickness in the thin group were significantly lower than those in the thick group (measured with Pentacam at 36 months, P < 0.001) and remained throughout the 5-year follow-up period. Both procedures had comparable postoperative logarithm of the minimum angle of resolution UDVAs, logarithm of the minimum angle of resolution corrected distance visual acuity, astigmatism, and mean keratometry values (36 months; P = 0.335, 0.286, 0.680, and 0.365, respectively). Corneal biomechanical analysis revealed that the thin group had a significantly higher stiffness parameter at the first applanation than the thick group at the 2-year follow-up (P = 0.036) while other parameters were equivalent. The outcomes of keratoplasty with donor tissue are comparable regardless of the thickness of the graft, which suggests that transplantation with either type of the split corneal procedure for DALK in patients with keratoconus is feasible.

Clinical profile and outcomes of rejection after deep anterior lamellar keratoplasty in keratoconus.

To report the clinical features and management outcomes of rejection after deep anterior lamellar keratoplasty (DALK). The clinical features, indications, predisposing risk factors, management, and outcome of six eyes of six patients with rejection after DALK were analyzed retrospectively. The median time of rejection from the day of surgery was 12 (range 3-36) months. Median duration of symptoms was 4 (range 2-28) days. The indication for DALK was keratoconus in all eyes. The clinical features at presentation included graft haze, vascularization, and melt at the graft-host junction. The risk factors noted were noncompliance to steroids in all eyes, vernal conjunctivitis (four eyes), and eccentric graft (one eye). The rejection episode reversed with topical steroids in all eyes and intravenous methylprednisolone in one eye. One eye developed secondary fungal keratitis after initial recovery and one eye had a second episode of rejection 3 months later, which resulted in progressive vessels and lipid keratopathy in the visual axis. The median best corrected visual acuity was 20/40 (range 20/30-20/200). Severe stromal rejection can present with graft melt. Repeat episodes of rejection can occur on sudden cessation of topical steroids. Prompt recognition of clinical signs and symptoms with timely management helps in quick reversal of the rejection episode. Reversal of graft rejection results in good visual outcomes.

Tissue addition keratoplasty in keratoconus: Trends and concerns.

Tissue addition keratoplasty in keratoconus: Trends and concerns.

Surgical Tips for Improving Success Rate of Deep Anterior Lamellar Keratoplasty in Keratoconus

This article aims to provide some personal surgical tips to increase the success rate of deep anterior lamellar keratoplasty (DALK), a very advantageous yet complex procedure for treating keratoconus. The most troublesome surgical step is obtaining a successful pneumatic dissection of the deep stromal tissue, allowing the exposure of a deep cleavage plane. The following tips may aid the trainee surgeon in mastering this step, among others: performing a deep trephination, using intraoperative anterior segment optical coherence tomography and/or femtosecond laser, exploiting the red reflex after pupil dilation, using the ophthalmic viscoelastic device in case of bubble formation failure. Approaches for reducing postoperative astigmatism are employing large-diameter grafts and using intraoperative keratoscopy with digital ring analysis. In conclusion, different tips can shorten the DALK learning curve and help to obtain better results from this surgery. Standardizing this surgical technique is paramount to reduce "human errors" and broaden its range of applicability.

Analysis of visual and refractive results after wedge resection for high astigmatism after penetrating keratoplasty in keratoconus.

To analyze visual and refractive results after wedge resection to correct high astigmatism after penetrating keratoplasty (PK) for keratoconus. Cornea Unit of the Centro de Oftalmología Barraquer Barcelona, Spain. A retrospective quasi-experimental, before and after study. Patients who developed high astigmatism or ectasia in the graft-host junction after PK were treated with wedge resection. The following variables were studied before the surgery, 1-year after and at the final visit: uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive and topographic astigmatism and spherical equivalent. Vectorial analysis of the astigmatism changes was performed. Fifty-one eyes were included with a mean follow-up of 4.19 ± 3.09 years. Mean refractive astigmatism was 11.47 ± 3.57 diopters (D) pre-operatively and 4.79 ± 3.32 D at the final follow-up (p < 0.001). The mean centroid changed from 2.65 ± 11.82 D at 23 degrees preoperatively to 0.35 ± 5.86 D at 127 degrees postoperatively. Concerning spherical equivalent, the mean preoperative value was -3.10 ± 4.15 D and the mean postoperative value was -1.55 ± 3.41 D (p = 0.002). Mean pre-operative and final follow-up UDVA were 1.25 ± 0.27 and 0.84 ± 0.50 (p < 0.001). Mean Pre-op and final follow-up CDVA were 0.27 ± 0.19 and 0.24 ± 0.24. Wedge resection is a useful surgical procedure to correct high astigmatism. It is a safe technique with moderate efficacy and may be considered as initial procedure of choice in high astigmatism due to long-term ectasia in the graft-host junction after PK for keratoconus.

Comparative analysis of posterior cornea between hydrops in keratoconus and Haab's striae in primary congenital glaucoma

AbstractPurpose: More eyes with keratoconus (KC) require keratoplasty after hydrops when compared to those after haab striae in primary congenital glaucoma (PCG). To compare descemet's membrane (DM) tear morphology in KC and PCG eyes using ASOCT and histopathology.Methods: ASOCT of KC eyes with hydrops (n = 12) and PCG eyes with Haab's striae (n = 15) were evaluated and compared with healthy eyes (n = 14) for descemet's membrane/ pre‐descemet's layer (DM‐PDL) morphology. These features were also assessed on histopathology of corneal button obtained from KC eyes (n = 14) and PCG (n = 13) after keratoplasty and compared with control tissues (retinoblastoma not involving cornea, n = 6) on light microscopy and immunostaining.Results: ASOCT showed thinner DM‐PDL in KC eyes(47.1 ± 25.5 μ) than that of PCG (77.2 ± 26.2 μ) (p = 0.01) inside areas of healed hydrops/ Haab's striae. DM‐PDL detachment was seen in 90% of KC eyes and 26% of PCG eyes. The height and angle of DM‐PDL detachment of KC eyes was more than that of PCG eyes. Similar to ASOCT findings, histopathology showed thinner DM‐PDL in KC eyes (62.6 ± 57.3 μ) compared to PCG (80.3 ± 78.7 μ) inside areas of healed hydrops/ Haab's striae but thicker than that of controls (32.6 ± 7.8 μ) (p‐0.01).Conclusions: Lesser fibroproliferative response and greater height of detachment ensure a poor healing after acute DM/ PDL tears in KC. This differential response of the posterior cornea may be responsible for greater need for keratoplasty in KC versus in PCG.

Management of Late Descemet's Membrane Detachment After Penetrating Keratoplasty in Keratoconus.

The purpose of this study was to describe the feasibility of Descemet membrane endothelial keratoplasty (DMEK) as a treatment modality for spontaneous detachment of DM (DMD) decades after penetrating keratoplasty (PK) for keratoconus. We describe the clinical characteristics and therapeutic surgical approach in 6 eyes of 5 patients with DMD. Clinical images, anterior segment optical coherence tomography scans, and histological findings are presented. Mean age of patients at time of diagnosis was 60 years (range 56-66 years). Mean interval between PK and occurrence of DM detachment was 36 years (range 29-45 years). In 4 of 6 eyes, air injections into the anterior chamber were initially attempted to reattach DM to the stroma but without long-lasting effect. Two eyes underwent repeat PK because of pronounced ectasia after long-standing DMD and stromal scars. DMEK was performed successfully in 4 eyes leading to an increase in visual acuity and a reduction in central corneal thickness. Electron microscopy showed abnormal vacuolar inclusions and collagenous material in the posterior nonbanded layer and a separation of the anterior banded layer from the posterior nonbanded layer. This case series provides evidence that DMEK is a viable option in eyes with spontaneous DM detachment after PK. Visual outcome is limited by the persisting high astigmatism in the ectatic cornea. Illustrated by a small series of patients, the results of DMEK in this condition are presented and new findings about the pathophysiology are given.

Keratoplasty for keratoconus: advantages and disadvantages

Keratoconus is a progressive bilateral corneal ectasia, accompanied by loss of vision due to high irregular astigmatism, which is the leading indication for corneal transplantation. The review presents a variety of surgical corneal transplantation techniques for keratoconus available today and discussed their advantages and disadvantages.

Keratoplasty for Keratoconus in Young Patients: Demographics, Clinical Features, and Post-transplant Outcomes

To examine pretransplant findings and outcomes of corneal transplants for keratoconus in children. Retrospective cohort (national registry) study. Data on all patients aged 16 or younger (n=170) who had a first transplant for keratoconus between 2003 and 2018 in all corneal transplant centers in the UK were compared to adult patients aged 17 and older (n=7,191). The influence of demographic variables, pretransplant corneal findings, and transplant type on 2-year visual, rejection-free, and transplant survival outcomes was examined. Children had poorer pretransplant visual acuity and higher rates of corneal vascularization and ocular surface disease than adults. However, 2-year post-transplant corrected visual acuity reached 20/20 or better in 35% of children compared to 28% of adults (P=.1). Transplant rejection and failure rates were 11% (P=.79) and 3% (P=.31), respectively, for children, which were comparable to rates for adults. Endothelial rejection was reported following penetrating keratoplasty (PK) in 13% of children (10% in adults). Irreversible rejection was not recorded for any transplant in a child. Despite a lack of difference in transplant outcomes, there was a significant age effect in the Cox regression model for transplant rejection, such that for every 5-year increase in age there was a 6% reduction in the hazard of rejection. Transplant survival following anterior lamellar keratoplasty and PK in children was similar. Young keratoconus patients have excellent transplant outcomes and visual results comparable to adults. Overall, the hazard of rejection was found to decrease with advancing age. However, in this large cohort of young patients with keratoconus and poor vision, there is no evidence of outcome advantage in delaying transplant until adult years.

Comment on "Impact of ultrasound and optical biometry on refractive outcomes of cataract surgery after penetrating keratoplasty in keratoconus".

Comment on "Impact of ultrasound and optical biometry on refractive outcomes of cataract surgery after penetrating keratoplasty in keratoconus".

In Vivo Confocal Microscopy of Stromal Lenticule Addition Keratoplasty for Advanced Keratoconus.

To investigate the in vivo corneal microscopic changes after femtosecond laser-assisted stromal lenticule addition keratoplasty in keratoconus by means of in vivo confocal microscopy. Patients affected by advanced keratoconus were included in the study. Negative meniscus-shaped stromal lenticules, produced with a femtosecond laser (VisuMax; Carl Zeiss Meditec) from eye bank corneas were transplanted into a stromal pocket dissected in the recipient cornea at a depth of 120 µm. In vivo confocal microscopy was performed during the 12-month follow-up to investigate changes of the corneal and lenticule structure. Ten patients were enrolled in the study. No changes of the dendritic cell population were documented during the follow-up period. Mild edema and stromal keratocyte activation gradually decreased during the first month. Subbasal nerve density returned to preoperative values after 6 months. Donor-recipient interfaces appeared hyperreflective but gradually improved over time with significantly reduced reflectivity after 3 months. No evidence of stromal inflammatory cell migration or matrix opacification was observed. Endothelial and keratocyte density remained stable over time. A variable degree of stromal radially distributed folds, not visible on biomicroscopy, was observed in the lenticule and in the posterior recipient stroma. Stromal lenticule addition keratoplasty produces transitory nerve plexus density reduction and minor inflammatory reaction that rapidly decreases during the first month. Donor-recipient interface reflectivity is comparable to a femtosecond laser refractive procedure with no sign of stromal opacification or stromal rejection in 1 year of follow-up. [J Refract Surg. 2020;36(8):544-550.].

Results of confocal microscopy of the cornea after bandage therapeutic-optical keratoplasty in keratoconus

To compare the light confocal microscopy appearance of the cornea before and after BTOK surgery. We examined 15 patients (15 eyes) with progressive keratoconus (7 eyes with Amsler stage I KC and 8 eyes with Amsler stage III KC), who subsequently underwent BTOCK surgery. Using the Confoscan-4 confocal light microscope (Nidek, Japan), we studied the structure of central and paracentral cornea. The exact zone of interest was determined individually depending on the location of the graft. In all cases, morphological changes in the cornea characteristic of the stage II and III KC were detected. Twelve months after the operation, there was an increase in the transparency of intercellular substance of the stroma with a clearer visualization of keratocyte nuclei in the optical zone as well as at the site of the graft. In the area of interface, tissue compaction in the form of diffuse fibrosis with local scar formation could be seen. Neither significant changes in the cell structure, nor a decrease in cell density were found in the central part of ectasia and the areas of clear visualization of the endothelium under the graft. Additional postoperative assessment of the level of corneal light scattering indicated a tendency towards restoration of stromal transparency and optical uniformity. As a result of interlayer graft implantation in the zone of corneal ectasia, a tendency to structural improvement in its central and paracentral parts was revealed. Local fibrosis in the interface area can indirectly indicate biomechanical «strengthening» of this zone.

Predictors of Bubble Formation and Type Obtained With Pneumatic Dissection During Deep Anterior Lamellar Keratoplasty in Keratoconus

To identify predictors of bubble formation and type during big-bubble deep anterior lamellar keratoplasty (BB-DALK) performed in keratoconus at different stages of severity. Retrospective Cohort Study. Setting: University Magna Græcia (Catanzaro, Italy); Study Population: Consecutive keratoconus patients undergoing BB-DALK from September 2014 to February 2019. Keratometric astigmatism, mean keratometry value (K-mean), highest keratometry value (K-max), thinnest point, anterior segment optical coherence tomography (AS-OCT)-based stage of ectasia. Rate of bubble formation and type; number and fate of micro-/macroperforation; conversion to mushroom keratoplasty (MK); comparison of parameters in patients with bubble formation vs failure and in type 1 vs type 2 bubble; areas under the curves (AUC) of preoperative parameters for distinguishing between bubble types. Pneumatic dissection succeeded in 113 of 155 eyes (72.9%), with 100 type 1 bubbles (88.4%), 11 type 2 (9.8%), and 2 mixed-type (1.8%). Microperforations were managed conservatively in type 1 bubbles; macroperforations occurring in both types of bubbles required conversion to MK. Preoperative K-mean and K-max values were significantly higher in eyes in which bubble formation succeeded (respectively, P= .006 and P < .013). Type 1 bubbles formed in eyes with significantly lower age, K-mean, and AS-OCT stages and higher pachymetric values (always P < .029). Age had the highest diagnostic power for discrimination between bubble types, followed by AS-OCT stage, pachymetry, K-mean, and astigmatism (respectively, AUC= 0.861, 0.779, 0.748, 0.700, 0.670). Older age and advanced stages of keratoconus were predictors of type 2 bubble formation during BB-DALK that was associated with an increased risk of complications.

Impact of ultrasound and optical biometry on refractive outcomes of cataract surgery after penetrating keratoplasty in keratoconus

To analyse the impact of ultrasound and optical intraocular lens (IOL) calculation methods on refractive outcomes of cataract phacoemulsification performed after penetrating keratoplasty (PK) in keratoconus. Phacoemulsification cataract surgery was performed on 42 eyes of 34 patients with keratoconus who had previously undergone PK. The IOL power was determined by using both standard and corneal topography-derived keratometry using the SRK/T formula. We used two independent methods-ultrasound biometry (UB) and interferometry [optical biometry (OB)] for IOL calculation. The analysed data from medical records included demographics, medical history, best corrected visual acuity (BCVA) on Snellen charts, technique of IOL calculation and calculation formula and its impact on final refractive result. BCVA ranged from 0.01 to 0.4 (mean 0.09±0.19) before surgery and ranged from 0.2 to 0.7 (mean 0.38±0.14) at 1mo and from 0.2 to 1.0 (mean 0.56±0.16) (P<0.05) at 3mo, postoperatively. The refractive aim differed significantly from the refractive outcome in both the UB and OB groups (P<0.05). There was no statistically significant difference in the accuracy of the two biometry methods. The refractive aim in keratoconus eyes post-PK is not achieved with either ultrasound or OB.

Удачный исход кератопластики при кератоконусе после развившейся болезни роговичного трансплантата (клинический случай)

Удачный исход кератопластики при кератоконусе после развившейся болезни роговичного трансплантата (клинический случай)

Surgical management of spontaneous, late-onset Descemet membrane detachment after penetrating keratoplasty for keratoconus: a case report

BackgroundTo report a surgical method for treating corneal oedema in a case of late-onset Descemet membrane detachment after penetrating keratoplasty.Case presentationA 55-year old patient presented with sudden visual loss in his left eye 28 years after penetrating keratoplasty for keratoconus. Slit-lamp biomicroscopy revealed a distortion of the corneal graft anatomy with protrusion of the graft and peripheral thinning and steepening in the residual host tissue, accompanied by corneal graft oedema. Anterior segment optical coherence tomography revealed detachment of Descemet membrane localized to the area of the graft oedema. We proceeded with a full-thickness, partially circumferential incision in the graft-host junction, followed by repositioning and re-suturing of the graft in place, and intracameral air injection in order to achieve reattachment of Descemet membrane.ConclusionsCorneal graft repositioning in combination with re-bubbling may represent an effective therapeutic option in keratoconic patients with peripheral thinning in the residual host corneal tissue and subsequent Descemet membrane detachment.

Comparison of visual and topographic outcomes of deep-anterior lamellar keratoplasty and penetrating keratoplasty in keratoconus.

To compare visual, surgical and topographic outcomes of deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PK) for keratoconus (KC). In this multicenter, prospective, randomized clinical trial 76 eyes of 71 KC patients operated between January 2011 and July 2014 in 2 tertiary referral hospitals were included. Consecutive patients were alternately selected to receive one of the two surgical methods. Thirty eight eyes underwent DALK with the big-bubble technique and 38 eyes underwent PK. Mean best spectacle corrected visual acuity (BSCVA) at the first postoperative week (P=0.012) and the first postoperative month (P<0.001) was statistically significantly higher in DALK group. The mean BSCVA at 12mo was not significantly different for DALK (0.30±1.99 logMAR) versus PK (0.40±0.33 logMAR) (P=0.104). The 76.3% of the eyes had a BSCVA over 0.5 in DALK and 47.4% in PK group (P=0.009). The 7.9% of the eyes had a BSCVA of 1.0 in DALK and 5.3% in PK group (P=0.644). Mean spherical equivalent was -2.94 D in DALK and -3.09 D in PK group. Mean topographic astigmatism was 4.62 D and 4.18 D respectively. Regular topographic patterns were observed in 31 (81.6%) of DALK and 29 (76.3%) of PK (P=0.574). The most frequent topographic pattern was oblate asymmetric bow tie, seen in 39.5% in DALK and 23.7% in PK. Big bubble DALK provides an earlier visual improvement compare to PK. However, visual and topographic outcomes are similar to those in PK at 1y. Postoperative complications including rejection and intraocular pressure elevation are more frequent in PK. DALK is a safer alternative to PK for KC. However, intraoperative perforation of the Descemet's membrane is a significant complication.

Repeat Keratoplasty for Failed Deep Anterior Lamellar Keratoplasty in Keratoconus: Incidence, Indications, and Outcomes.

To analyze the incidence, indications, and clinical outcomes of penetrating keratoplasty (PK) and repeat deep anterior lamellar keratoplasty (DALK) after failed DALK for keratoconus. This retrospective interventional case series reviewed the medical records of patients with keratoconus who underwent DALK and were followed up for at least 1 year. Patients who underwent PK or repeat DALK for failed DALK were identified. The incidence, indications, and clinical outcomes after repeat keratoplasty were assessed. A total of 382 consecutive eyes with keratoconus underwent DALK over a 9-year period. Graft failure was observed in 14 eyes (3.7%). The reasons for the graft failure included nonhealing epithelial defects (n = 1), pseudoanterior chamber (n = 2), patient dissatisfaction with vision (n = 4), interface opacification (n = 4), high astigmatism (n = 1), and recurrence of keratoconus in the graft (n = 2). Of these 14 eyes with graft failure, 12 eyes underwent PK (n = 11) or repeat DALK (n = 1). At the most recent examination, which was performed 49.7 ± 25.2 months after the secondary graft, all regrafts were clear. There was no significant difference between eyes with clear first grafts and eyes that underwent PK or repeat DALK in visual outcomes at the final examination. Graft rejection was the most common complication, which was encountered in 75% of the regrafts. The prognosis for repeat keratoplasty was excellent, and the outcomes of secondary grafts were comparable to those of primary DALK grafts. However, the rate of rejection with secondary grafts was high, necessitating close follow-up after PK and repeat DALK performed for failed DALK.