Deep Anterior Lamellar Keratoplasty For Keratoconus Research Articles

Suture-related complications after deep anterior lamellar keratoplasty for keratoconus.

The purpose of this study is to determine the incidence of suture-related complications, their risk factors, and effects on the clinical outcomes after deep anterior lamellar keratoplasty (DALK) for keratoconus. In this retrospective, comparative, interventional study, the records of consecutive patients with keratoconus who underwent DALK were reviewed for suture-related complications. Univariate analyses were used to identify risk factors for suture complications. We compared groups with and without suture-related complications to evaluate the effects of these complications on clinical outcomes after DALK. Of the 633 DALKs, 438 eyes (69.2%) developed suture complications including loose sutures (32.7%), spontaneous suture rupture (30%), sterile suture abscesses (22.8%), suture tract vascularization (16.4%), suture erosion (10.3%), and suture cheese wiring (6.8%). Vernal keratoconjunctivitis increased the incidence of sterile suture infiltration, premature suture loosening, and suture tract vascularization. Loose suture was observed more commonly in larger graft size, while spontaneous suture rupture was associated with late suture removal. There was no statistically significant difference in postoperative outcomes including visual acuity, refraction, graft rejection, and failure in eyes with and without suture complications. However, suture-related complications were directly associated with sight-threatening ocular morbidities, including graft rejection (39 eyes), ulcer (1 eye), and failure (2 eyes). Suture-related complications frequently occurred after DALK for keratoconus. Ocular surface inflammation, large grafts, and late suture removal increased the risk of suture-related complications. While these complications had no negative impact on clinical outcomes in the majority of cases, some of them led to sight-threatening morbidity, underlining the importance of early diagnosis and treatment.

Anterior segment optical coherence tomography for the detection and management of early keratoplasty complications

AbstractPurpose: This study aimed to assess the contribution of anterior segment optical coherence tomography (AS‐OCT) in the detection of early postoperative complications following penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK) in order to guide their management.Methods: A single‐center, prospective study, designed to evaluate the postoperative results of 42 eyes who had PK (39 eyes) and DALK (3 eyes) for various diagnoses. Complications occurring between the first and 7th day after surgery were recorded. AS‐OCT was performed to assess central corneal thickness (CCT), Descemet's membrane (DM) position, graft‐host junctions (GHJ), and iridocorneal angle (ICA) opening.Results: Early postoperative complications were detected in 4 eyes (9.5%). Among them, 2 eyes (patients 1 and 2) had PK for corneal perforation, and 2 eyes (patients 3 and 4) had DALK for keratoconus. Patient 1 had an early graft ectasia. Corneal thinning was first detected on the 6th postoperative day by CCT measurement on AS‐OCT. He underwent a second PK with a favourable outcome. Patient 2 had persistent corneal edema on the 4th postoperative day. AS‐OCT revealed graft steps at the GHJ. After surgical revision, the graft became clear and the GHJ were well‐apposed on AS‐OCT. Patient 3 had important graft edema (CCT 1005 μm) secondary to DM detachment diagnosed on the first postoperative day with AS‐OCT. She was treated with an intracameral air injection leading to the reattachment of DM and regression of the edema. Patient 4 had on the first postoperative day a pupillary block successfully managed with a peripheral iridotomy leading to the reopening of the ICA seen on AS‐OCT.Conclusions: AS‐OCT is a non‐contact and reproducible imaging tool that proved to be useful to identify early postoperative complications after keratoplasty and to guide their management. It allows for a quantitative and objective assessment of the anterior segment behind a usually non‐transparent corneal graft.

Axial length measurements in same sized DALK grafts – new insights

Introduction: At the Sri Jayawardenapura General Hospital (SJGH), Deep Anterior Lamellar Keratoplasty (DALK) for keratoconus is performed by a single surgeon with graft sizing done on vertical corneal height and same-sized grafting done for all patients.Method: A single centre cross-sectional descriptive study was conducted from 01. 01. 2020 to 01. 04. 2020 at the SJGH. Patients who had completed two years of follow up after DALK for keratoconus had refraction, topography and biometry on a planned hospital visit.Results: The study included 71 patients (97 eyes). Mean age at surgery was 23.9 years; standard deviation (SD) – 6.9 years. The mean, postsurgical duration was 63.1 months (SD=23.4) and refractive SE was – 1.18 D (SD=1. 88). Hyperopic SE was seen in 21.5% of eyes. Mean axial length (AXL) was 23.50 mm (SD=1.16) and mean anterior chamber depth (ACD) was 3.578 mm (SD=0.36 mm). Mean AXL had significant negative correlation with SE (r= -0.676, P=0.000). ACD was correlated with average topographic keratometry (P=0.048). Mean topographic cylinder was -3.237 D (SD=1.85).Conclusion: Axial length measurements should be performed in pre operative work up in DALK. Patients with short eyes need to be counseled for postoperative hyperopia. Vitreous length may be a better measurement than axial length as it may not be affected by changes in ACD in keratoconus.

Impact of cone base diameter on outcomes of deep anterior lamellar keratoplasty in keratoconus.

To evaluate the outcomes of deep anterior lamellar keratoplasty (DALK) in treatingkeratoconus in relation to cone base diameter (CBD). A retrospective study. Sixty-one eyes of 49 keratoconus patients who underwent DALK between 2009 and 2018 were enrolled. Preoperative and postoperative uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), spherical equivalent, and astigmatism were measured. Scheimpflug tomography (Pentacam) was used to measure the cone base area (CBA) and CBD using MATLAB software. The mean age of the patients was 20.8 ± 6.1years old, and the mean follow-up time was 27.3 ± 15.2months. Mean UCVA improved from 1.23 ± 0.48 to 0.57 ± 0.27 (LogMAR, 95% CI [0.52, 0.80]; P < 0.001), whereas mean BCVA improved from 0.98 ± 0.55 to 0.18 ± 0.13 (95% CI [0.66, 0.94]; P < 0.001). The mean spherical equivalent decreased by 4.53 ± 5.65 D (95% CI [- 6.25, - 2.82]; P < 0.001), with little change in astigmatism (95% CI [- 1.39, 0.64]; P = 0.457). The postoperative BCVA in the patients with CBD < 5.07mm and corneal curvature ≥ 55D was significantly better than those whose CBD ≥ 5.07mm (0.14 ± 0.09 vs 0.25 ± 0.15, P = 0.001). The follow-up time was negatively correlated with the BCVA (P = 0.004). In this study, outcomes of DALK in keratoconus were related to CBD and corneal curvature. Patients with large CBD (≥ 5.07mm) where the corneal curvature ≥ 55D are more likely to have poor visual outcomes after DALK.

Evaluation of the effect of preoperative corneal curvature on the successful formation of the big bubble formation in deep anterior lamellar keratoplasty for keratoconus

Background New approaches have been created to raise the chances of achieving big bubble (BB) in deep anterior lamellar keratoplasty (DALK); however, the BB formation is still uncertain in all cases. Other factors likely contribute to the success of bubble formation. Aim To evaluate the effect of preoperative curvature of the cornea on the success of BB formation in DALK for keratoconus. Design A prospective, comparative, nonrandomized study. Patients and methods The study was performed on 50 keratoconus patients. We compared the data of 25 patients who had successful type-1 bubble formation versus another 25 patients in whom the bubble formation failed. Both groups were compared regarding the keratometric readings recorded from the preoperative pentacam. Results The analysis showed statistically significant lower K1, K2, and Km values in the group where BB has been successfully achieved. We also found that lower K1 value was the only significant studied factor after the multivariate analysis. Conclusion Keratoconus patients with preoperative flatter corneas have slightly higher chances for successful BB formation during DALK surgery.

Comparison of penetrating keratoplasty and deep anterior lamellar keratoplasty in keratoconus eyes with vernal keratoconjunctivitis.

Purpose:The purpose of the study is to compare outcomes after penetrating keratoplasty (PK) against deep anterior lamellar keratoplasty (DALK) for keratoconus in patients with vernal keratoconjunctivitis (VKC).Methods:Keratoconic patients with VKC who received PK (n = 55, group 1) or DALK (n = 62, group 2) were retrospectively enrolled. The Student’s t test, Mann–Whitney test, Fisher’s exact test, chi-square test, and Kaplan–Meier survival curve were used to compare outcomes between the groups.Results:The follow-up period was 59.4 ± 44.1 and 62.4 ± 38.9 months in groups 1 and 2, respectively (p = 0.70). Postoperative best spectacle-corrected visual acuity was 0.24 ± 0.18 and 0.29 ± 0.19 logMAR, respectively (p = 0.13). Graft rejection occurred in 34.6% and 25.8% of eyes in groups 1 and 2, respectively (p = 0.30). Groups 1 and 2 were comparable in the rates of cataract (3.6% and 12.9%, respectively, p = 0.07) and high intraocular pressure (3.6% and 8.1%, respectively, p = 0.31). Compared with the eyes with inactive VKC, PK eyes that experienced postoperative disease reactivation had a higher rate of suture abscesses (10.9% versus 50.0%, respectively, p = 0.01) and suture-tract vascularization (6.5% versus 33.3%, respectively, p = 0.03). Similarly, disease reactivation significantly increased suture abscesses from 27.3% to 51.7% (p = 0.03) and suture-tract vascularization from 18.2% to 49.6% (p = 0.005) in the DALK group. The graft survival rates were 95.3% in group 1 and 87.9% in group 2 at the 4-year follow-up, with mean durations of 14.4 and 11.1 months, respectively (p = 0.20).Conclusion:The results indicate no difference in outcomes between PK and DALK for keratoconus in patients with VKC. Postoperative VKC reactivation increased the rate of suture-related problems after both techniques of keratoplasty.

Customized Toric Intraocular Lens Implantation in Eyes with Cataract and Corneal Astigmatism after Deep Anterior Lamellar Keratoplasty: A Prospective Study.

Purpose To investigate the effectiveness of toric intraocular lenses (IOLs) for treating corneal astigmatism in patients with cataract and previous deep anterior lamellar keratoplasty (DALK). Setting San Giovanni-Addolorata Hospital, Rome, Italy. Design Prospective interventional case series. Methods Patients undergoing cataract surgery after DALK for keratoconus were enrolled. Total corneal astigmatism (TCA) was assessed by a rotating Scheimpflug camera combined with Placido-disk corneal topography (Sirius; CSO, Firenze, Italy). A customized toric IOL (FIL 611 T, Soleko, Rome, Italy) was implanted in all eyes. One year postoperatively, refraction was measured, the IOL position was recorded, and vectorial and nonvectorial analyses were performed to evaluate the correction of astigmatism. Results Ten eyes of 10 patients were analyzed. The mean preoperative TCA magnitude was 4.92 ± 1.99 diopters (D), and the mean cylinder of the IOL was 6.18 ± 2.44. After surgery, the difference between the planned axis of orientation of the IOL and the observed axis was ≤10° in all eyes. The mean surgically induced corneal astigmatism was 0.35 D at 20°. The mean postoperative refractive astigmatism power was 1.13 ± 0.94 D; with respect to preoperative TCA, the reduction was statistically significant (p < 0.0001). The mean change in astigmatism power was 3.80 ± 1.60 D, corresponding to a correction of 77% of preoperative TCA power. Nine eyes out of 10 had a postoperative refractive astigmatism power ≤ 2D. Conclusions Toric IOLs can effectively correct corneal astigmatism in eyes with previous DALK. The predictability of cylinder correction is partially lowered by the variability of the surgically induced changes of TCA. This trial is registered with NCT03398109.

Outcomes of Toric Iris-Claw Phakic Intraocular Lens Implantation After Deep Anterior Lamellar Keratoplasty for Keratoconus.

To assess visual and refractive outcomes of toric iris-claw phakic intraocular lens (IOL) implantation in patients who had previously undergone deep anterior lamellar keratoplasty (DALK). Retrospective case series including 24 eyes of 24 patients implanted with toric Artiflex or Artisan (Ophtec BV, Groningen, Holland) phakic IOL following DALK for keratoconus. During a 12-month follow-up, the main outcome measures were uncorrected and corrected distance visual acuities (UDVA and CDVA), refractive error components, topographic parameters, and endothelial cell count. Alpins vectorial analysis was performed. At the last follow-up, the spherical equivalent (SE) was within ±0.50 diopters (D) in 71% of eyes and within ±1.00 D in 92% of eyes. Mean refractive astigmatism was reduced from -4.92 ± 1.55 D (range: -2.50 to -8.00 D) preoperatively to -0.66 ± 0.61 D (range: -2.00 to 0.00 D) after treatment, and 76.5% of cases were within ±1.00 D. No significant differences (P = .123) were detected in spherical equivalent values between 3- and 12-month follow-up visits. No eyes lost lines in CDVA, and 54% of eyes gained one or more lines. Postoperative UDVA was 20/40 or better in 88% of eyes. Efficacy and safety indexes at 12 months were 0.93 and 1.00, respectively. Mean endothelial cell loss was 6.10% at 12 months postoperatively. No intraoperative or postoperative complications were noted over the follow-up period. The implantation of a toric iris-claw phakic IOL has shown high efficacy and safety in this series and may be considered as a reasonable option for the management of refractive errors after DALK. [J Refract Surg. 2017;33(8):538-544.].

Systematic review comparing penetrating keratoplasty and deep anterior lamellar keratoplasty for management of keratoconus.

Perception of reduced incidence of graft rejection after deep anterior lamellar keratoplasty (DALK) has attracted many surgeons towards this technique in keratoconus. This review aims to compare the visual, refractive and graft outcomes after penetrating keratoplasty (PK) and DALK for keratoconus. Electronic searches of PubMed, MEDLINE, EMBASE, Latin American and Caribbean Health Sciences Literature database (LILACS), metaRegister of Controlled Trials (mRCT), ClinicalTrial.gov and the WHO International Clinical Trials Registry Platform (ICTRP) were performed. We included randomized control trials (RCTs) and comparative studies to assess primary and secondary outcomes after PK and DALK in eyes with keratoconus. Primary outcome was best-corrected visual acuity (BCVA) LogMAR at ≥6 months. Secondary outcomes included number of patients with BCVA≥0 LogMAR, uncorrected visual acuity (UCVA) LogMAR, spherical equivalent (SE), refractive and keratometric astigmatism, endothelial cell density (ECD) cell/mm2, graft rejection and graft survival. Eighteen studies (including 2 RCTs) compared DALK (965 eyes) and PK (2402 eyes) for keratoconus. There was strong evidence through RCTs suggesting better LogMAR BCVA at ≥6 months and better LogMAR UCVA with PK; reduced refractive astigmatism and rejection with DALK and no difference in SE and keratometric astigmatism. Moreover, there was weak evidence to suggest better BCVA≥0 LogMAR after PK and no difference in ECD between the two techniques. Despite the popularity of DALK amongst corneal surgeons for keratoconus, there is a paucity of high quality RCTs. The existing limited evidence confirms reduced rejection and refractive astigmatism with DALK but better visual outcomes with PK. Internationally agreed data sets and follow-up protocol are warranted.

Clinical evaluation of Toric phakic posterior chamber intraocular collamer lens implantation for ametropia following deep anterior lamellar keratoplasty for keratoconus

Background Postoperative ametropia, especially large astigmatism after deep anterior lamellar keratoplasty (DALK) for keratoconus often results in poor visual acuity. Though postoperative ametropia can be corrected by wearing glasses or performing corneal refractive surgery, the visual quality of patients is still poor, and the operations are difficult to implement because of insufficient corneal thickness. Toric intraocular collamer lens (TICL) implantation appears to have good corrective efficacy on severe astigmatism, but the research on the eyes after DALK is still less. Objective This study was to evaluate the efficacy and safety of TICL implantation for the ametropic eyes following DALK for keratoconus. Methods This study protocol was approved by Ethic Commission of Nanjing Drum Tower Hospital, and written informed consent was obtained from each patient prior to any medical procedure. A self-controlled serial observational research was carried out. Eight ametropic eyes of 8 patients who received the DALK for keratoconus before 18 months were enrolled in Nanjing Drum Tower Hospital from August 2011 to March 2012, with the spherical diopter range from 0 D to -7.5 D and cylindrical diopter range from -2.5 D to -6.0 D. TICL implantation was performed on the eyes. The eye examinations were carried out before surgery and 1 week, 3 months, 6 months, 1 year and 2 years after surgery, including uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), comprehensive optometry, corneal astigmatism degree, the central corneal thickness and anterior chamber depth (ACD), corneal endothelial cell counts (ECD), intraocular pressure. The examination outcomes were compared before and after surgery. The intraoperative and postoperative complications were observed to evaluate the safety of TICL implantation for the ametropic eyes following DALK for keratoconus. Results The UCVA and BCVA were obviously improved at 6 months after TICL implantation in comparison with before surgery and maintained stable during the follow-up duration. The mean spherical diopter was from -0.5 D to -1.0 D and the mean cylindrical diopter was from -0.5 D to -2.0 D after surgery. The corneal endothelial cell counts were (2 520.2±307.2), (2 496.2±306.2), (2 469.6±304.5), (2 432.0±305.4), (2 383.4±309.4)/mm2, and the intraocular pressures were (14.57±3.75), (16.62±4.21), (16.57±3.56), (15.66±3.37), (15.13±3.48) mmHg, showing insignificant differences among different time points (F=0.375, P=0.825; F=9.871, P=0.394). No significant differences were found in mean ACD and intraocular pressure between before and after surgery (t=1.56, P=0.16). The axial deviation of TICL was less than 10° in all the operated eyes 6 months after surgery. No intraoperative and postoperative complications were found during the follow-up duration. Conclusions TICL implantation is a safe and effective alternative and viable approach to myopic and astigmatism patients following DALK for keratoconus. Key words: [Key words]Lens implantation, intraocular; Phakic intraocular lens; Ametropia/surgery; Astigmatism/surgery; Keratoconus/surgery; Corneal transplantation/complications; Treatment outcome; Toric intraocular collamer lens

An Analysis of Factors Influencing Quality of Vision After Big-Bubble Deep Anterior Lamellar Keratoplasty in Keratoconus

To identify causes of reduced visual acuity and contrast sensitivity after big-bubble deep anterior lamellar keratoplasty (DALK) in keratoconus. Prospective interventional case series. This study included 36 eyes in 36 patients with keratoconus who underwent DALK using the big-bubble technique. A bare Descemet membrane was achieved in all cases. Univariate analyses and multiple linear regression were used to investigate recipient-, donor-, and postoperative-related variables capable of influencing the postoperative quality of vision, including best spectacle-corrected visual acuity (BSCVA) and contrast sensitivity. The mean patient age was 27.7 ± 6.9 years, and the patients were followed for 24.6 ± 15.1months postoperatively. The mean postoperative BSCVA was 0.17 ± 0.09 logMAR. Postoperative BSCVA ≥20/25 was achieved in 14 eyes (38.9%), whereas a BSCVA of 20/30, 20/40, or 20/50 was observed in 15 eyes (41.7%), 6 eyes (16.6%), and 1 eye (2.8%), respectively. Preoperative vitreous length was significantly associated with postoperative BSCVA (β= 0.02, P= .03). Donor-recipient interface reflectivity significantly influenced scotopic (β=-0.002, P= .04) and photopic (β=-0.003, P= .02) contrast sensitivity. The root mean square of tetrafoil was significantly negatively associated with scotopic (β=-0.25, P= .01) and photopic (β=-0.23, P= .04) contrast sensitivity. Recipient age, keratoconus severity, donor-related variables, recipient trephination size, and graft and recipient bed thickness were not significantly associated with postoperative visual acuity or contrast sensitivity. Large vitreous length, higher-order aberrations, and surgical interface haze may contribute to poor visual outcomes after big-bubble DALK in keratoconus.

Traumatic Wound Dehiscence Associated with Graft Loss Following Deep Anterior Lamellar Keratoplasty

We report two unusual cases of wound dehiscence associated with graft loss following Deep Anterior Lamellar Keratoplasty (DALK). The first case was a 41-year-old man who had DALK for keratoconus, resulting in visual recovery. The patient returned 14 months later, after being struck with a fist on his left eye, resulting in complete loss of the graft and a tear in the Descemet’s Membrane (DM). Grafting with a preserved cornea resulted in gradually recovery in both graft clarity and visual acuity. The second case was a 46-year-old man who had undergone uneventful DALK for keratoconus. Running suture removal was performed at 21 months postoperatively. When he returned 6 days later, the graft was lost and intact DM exposed. Securing a preserved corneal graft over the DM resulted in gradual recovery. These results indicate that wound dehiscence associated with complete graft loss can occur following uneventful DALK. Presence of a recipient DM may act as a physical barrier to other ocular tissues.

Penetrating keratoplasty versus deep anterior lamellar keratoplasty for the treatment of keratoconus

To compare the outcome of penetrating keratoplasty (PKP) and deep anterior lamellar keratoplasty (DALK) in the surgical management of keratoconus (KC). A retrospective review was conducted of the medical records of all patients treated with PKP or DALK for KC at University of Iowa Hospitals and Clinics from January 1, 2000, to December 31, 2006. The main outcome measures were visual outcome, graft survival, and complications. Cases with a minimum follow-up of 6 months were included in the statistical analysis. Of 41 eyes that met the inclusion criteria, 30 eyes were treated with PKP and 11 eyes were treated with DALK. The mean follow-up was almost identical for eyes treated with PKP or DALK (21.9 vs. 22.5 months, respectively). At the most recent examination, the mean best spectacle-corrected visual acuity (BSCVA) was 20/28 for the PKP group and 20/29 for the DALK group (P = 0.77). The percentage of eyes that achieved BSCVA of 20/25 or better was higher in the PKP group than in the DALK group (77.3 vs. 45.5%, respectively), but this difference was not statistically significant (P = 0.72). Endothelial rejection occurred in 4 (13.3%) eyes after PKP. Visually significant interface haze occurred in the early postoperative course in 2 (18.2%) eyes after DALK. No cases of late-onset endothelial failure were found in either group. Treatment of KC with PKP or DALK is associated with similar visual outcomes, graft survival, and prevalence of sight-threatening complications.

Quality of Vision and Graft Thickness in Deep Anterior Lamellar and Penetrating Corneal Allografts

To compare visual function after deep anterior lamellar keratoplasty (DALK) with visual function after penetrating keratoplasty (PK) for keratoconus and correlate this with corneal thickness. Retrospective case series. Twenty-three patients (32 eyes) with unilateral or bilateral DALK or PK for keratoconus were analyzed for visual quality after suture removal. Evaluation included measurement of visual acuity, contrast sensitivity, and higher order aberrations (HOAs) (WaveScan; Visx, Santa Clara, California, USA). Readings were performed with both spectacle and rigid contact lens correction of refractive error. Total and residual stromal thickness after DALK was measured using optical coherence tomography (OCT) and correlated to visual quality. Eyes after PK had better visual acuity than eyes after DALK (P = .018). Subgroup analysis of DALK eyes revealed that the level of visual acuity was related to the thickness of residual recipient corneal stroma. Eyes with a recipient corneal bed thickness of <20 microm had visual acuities similar to eyes with a PK, whereas those with a recipient thickness of >80 microm had a significantly reduced visual acuity (P = .0009). Contrast sensitivity was similar in DALK and PK eyes. There was no significant difference in HOAs between eyes with DALK or PK. These data suggest that the main parameter for good visual function after DALK for keratoconus is the thickness of residual recipient stromal bed. An eye with a DALK with a residual bed of <20 microm can achieve a similar visual result as a PK.