Stromal lenticule addition keratoplasty with corneal crosslinking for corneal ectasia secondary to FS-LASIK:a case series

●AIM:To explore the clinical efficacy and safety of stromal lenticule addition keratoplasty(SLAK)with corneal crosslinking(CXL)on patients with corneal ectasia secondary to femtosecond laser-assisted in situ keratomileusis(FS-LASIK).●METHODS:A series of 5 patients undertaking SLAK with CXL for the treatment of corneal ectasia secondary to FS-LASIK were followed for 4-9mo.The lenticules were collected from patients undertaking small incision lenticule extraction(SMILE)for the correction of myopia.Adding a stromal lenticule was aimed at improving the corneal thickness for the safe application of crosslinking and compensating for the thin cornea to improve its mechanical strength.●RESULTS:All surgeries were conducted successfully with no significant complications.Their best corrected visual acuity(BCVA)ranged from 0.05 to 0.8-2 before surgery.The pre-operational total corneal thickness ranged from 345-404μm and maximum keratometry(Kmax)ranged from 50.8 to 86.3.After the combination surgery,both the corneal keratometry(range 55.9 to 92.8)and total corneal thickness(range 413-482μm)significantly increased.Four out of 5 patients had improvement of corneal biomechanical parameters(reflected by stiffness parameter A1 in Corvis ST).However,3 patients showed decreased BCVA after surgery due to the development of irregular astigmatism and transient haze.Despite the onset of corneal edema right after SLAK,the corneal topography and thickness generally stabilized after 3mo.●CONCLUSION:SLAK with CXL is a potentially beneficial and safe therapy for advanced corneal ectasia.Future work needs to address the poor predictability of corneal refractometry and compare the outcomes of different surgical modes.

Donor cornea quality used for penetrating keratoplasty vs deep anterior lamellar keratoplasty

Deep anterior lamellar keratoplasty(DALK) has recently been introduced as an alternative procedure to penetrating keratoplasty(PK) for corneal pathologies not affecting the corneal endothelium. DALK does not rely on donor endothelium and requires less rigid criteria for donor corneal tissue quality. Therefore, DALK makes it possible to use donor corneas deemed unsuitable for PK. Furthermore, lamellar keratoplasty allows acellular corneal tissue to be transplanted. As a result, long-term preservation techniques are being revisited to increase the availability of donor corneas and subsequently alleviate constraints of availability, cost, storage, and transportation in many countries. The recent alterations in corneal transplantation techniques and hence the type of donor cornea tissues used for each technique, may require corneal surgeons and eye banks to reevaluate their selection criteria. The purpose of this systematic review is to present an updated analysis on the type and quality of donor corneas used for PK and DALK, assess the influence of donor and eye bank factors on the quality of donor corneas, and determine whether any of these donor factors affect clinical outcomes, complications, and graft survivals.

Simultaneous tectonic Descemet stripping endothelial keratoplasty and tectonic Bowman layer transplant for the management of corneal perforation

AIM:To report the outcomes of three cases of corneal perforation managed with simultaneous tectonic Descemet stripping endothelial keratoplasty(t-DSEK)and tectonic Bowman layer transplant(t-BLT)as an alternative to tectonic penetrating keratoplasty(t-PKP).METHODS:Three eyes of three patients receiving simultaneous t-DSEK and t-BLT for corneal perforation were included.The technique for DSEK was modified depending on individual requirements.The t-BLT technique was standardised using an 8 mm graft and fixated with a running suture.Success was measured by the ability of this procedure to close a corneal perforation.RESULTS:All three cases achieved tectonic eye globe restoration and remained stable during the minimum 3-month observation period.Reinterventions were relatively common:2 cases required amniotic membrane transplant for persistent epithelial defects.One case required DSEK rebubbling.One case developed angle closure glaucoma requiring surgical peripheral iridectomy.CONCLUSION:Simultaneous t-DSEK and t-BLT may be a useful strategy for the management of corneal perforation as an alternative management to t-PKP for selected cases.

Penetrating keratoplasty in children under 3 years old with congenital corneal opacities

AIM:To evaluate the graft rejection and visual outcomes after penetrating keratoplasty(PK)in the presence of various congenital corneal opacities in children.METHODS:In this retrospective cohort study,children who underwent PK were then followed for 5 y.The patient’s medical records were collected from June 2014 until June 2019 and analyzed in December 2019.All patients were children under three years old with congenital corneal opacities with or without microcornea who came to a pediatric ophthalmologist and underwent PK in Jakarta Eye Center(JEC).Beforehand,all children have participated in a thorough evaluation for PK.In the case of severe microcornea was not advised to undergo surgery.The visual outcomes and graft survival rate were described in percentages.The graft survival plot was presented with Kaplan-Meier,while the visual acuity was analyzed using the Wilcoxon signed ranks test.RESULTS:Sixteen eyes from eleven patients(seven girls and four boys)underwent PK.The graft survival rate of the first 6,12,and 18 mo later of keratoplasty was 100%,83.3%,and 66.7%,respectively.The overall mean survival time is 22 mo(standard error 2.419),and no significant difference between the patients underwent PK before and after 36 mo of their age(P=0.52).The graft failure was 50%,and postsurgery complications included cataract 43.7%,band keratopathy 12.5%,and scleromalasia 6.25%.Wilcoxon test analysis of visual acuity post keratoplasty was not statistically significant(P=0.34),while overall showed 44%improvements of visual outcome for 5 y of follow-up.With a good survival at one year up to 22 mo(83.3%),the visual acuity could be achieved(63%),and showed improvements(44%)during follow-up.CONCLUSION:The complications are frequent for pediatric PK.Thus,corneal surgery on infants requires careful case selection,adequate pre-operative evaluation,skilled surgery(optical correction),very close cooperation family–physician,intensive post-operation care,and amblyopia management in the future.

Ocular biomechanical measurements on post- keratoplasty corneas using a Scheimpflug-based noncontact device

AIM： To analyse ocular biomechanical properties, central corneal thickness （CCT） and intraocular pressure （lOP） in post-keratoplasty eyes, as compared to normal subjects, with a new Scheimpflug-based technology. Moreover, biomechanical data were correlated with the size and age of the donor and recipient corneas. METHODS： Measurements were conducted on 46 eyes of 46 healthy patients without any corneal pathology （age： 53.83 ±20.8y） and 30 eyes of 28 patients after penetrating keratoplasty （age： 49.43 ±21.34y）. Ten biomechanical parameters, the CCT and lOP were recorded by corneal visualization Scheimpflug technology （CorVis ST） using high-speed Scheimpflug imaging. Keratometry values were also recorded using Pentacam HR system. Scheimpflug measurements were performed after 43.41± 40.17mo （range： 11-128mo） after the keratoplasty and after 7.64±2.34mo （range： 5-14mo） of suture removal. RESULTS： Regarding the device-specific biomechanical parameters, the highest concavity time and radius values showed a significant decrease between these two groups （P=0.01 and P 〈0.001）. None of other biomechanical parameters disclosed a significant difference. The CCT showed a significant difference between post keratoplasty eyes as compared to normal subjects （P= 0.003） using the CorVis ST device. The lOP was within the normal range in both groups （P=0.84）. There were no significant relationships between the keratometric data, the size of the donor and recipient, age of the donor and recipient and biomechanical properties obtained by CorVis ST. CONCLUSION： The ocular biomechanics remain stable after penetrating keratoplasty according to the CorVis ST measurements. Only two from the ten device-specific parameters have importance in the follow-up period after penetrating keratoplasty.

Central corneal epithelium self-healing after ring-shaped glycerin-cryopreserved lamellar keratoplasty in Terrien marginal degeneration

Dear Sir, I am Dr Yan-Long Bi, from the Department of Ophthalmology, Tongji University Affiliated to Tongji University School of Medicine, Shanghai, China. I write to present a case report of total limbal stem cells deficiency after treatment with ring-shaped lamellar keratoplasty secondary to Terrien marginal degeneration. During 3 years

Cryopreserved limbal lamellar keratoplasty for peripheral corneal and limbal reconstruction

This study aimed to evaluate the outcomes and described the recovery process of cryopreserved limbal lamellar keratoplasty（CLLK） for peripheral corneal and limbal diseases. Thirteen eyes of 12 patients with a mean age of 41±23.9 y were included. The average follow-up was 12.1±5.6 mo. Stable ocular surface was achieved in all eyes at last follow-up. Epithelialization originated from both recipient and graft in 9 eyes. We conclude that CLLK compensates for the shortage of donor corneas and cryopreserved limbal grafts provide epithelialization sources in ocular surface reconstruction.

Effect of Topical FK506 Used alone or Combined with Keratoplasty on Patients with Recurrent Mooren′s Corneal Ulcer

Purpose: To evaluate the efficacy of topical 0.1% FK506 used alone or combined with keratoplasty on patients with recurrent Mooren′s ulcer. Methods: This is a retrospective interventional consecutive case series. Nine patients (15 eyes) with recurrent Mooren′s ulcer were treated with topical 0.1% FK506 alone or combined with keratoplasty. Two eyes with ulcers involving less than half the corneal limbus were treated with topical 0.1% FK506. Of the other 13 eyes with ulcers involving more than half the limbus, twelve were treated with excision of the ulcer and adjacent conjunctiva combined with lamellar keratoplasty. One eye with a central impending corneal perforation was treated with penetrating keratoplasty.Topical 0.1% FK506 was given post-operatively to all thirteen eyes after re-epithelia-lisation of the cornea. FK506 levels in the surgically resected cornea and conjunctiva of the operated eyes were measured using enzyme immunoassay procedures. Twelve patients (17 eyes) with recurrent Mooren′s ulcer treated with lamellar keratoplasty combined with topical 0.1% dexamethasone were taken as the control. The main measure of the outcome was the recurrence of Mooren′s ulcer in the patients. Results: Nine patients (15 eyes) with recurrent Mooren′s ulcer were all successfully treated. Vision in 5 eyes improved by two lines or better after treatment. No recurrence was observed during the follow up period of 12 to 22 months. After topical application of 0.1% FK506, concentrations of 30～350 ng/g of FK506 were found in the cornea and conjunctiva. Seven eyes of Mooren′s ulcer in the control group recurred during the follow up period. Conclusion: Topical 0.1% FK506 used alone or combined with keratoplasty is a safe and effective therapy for patients with recurrent Mooren′s ulcer.

Clinical associations of corneal neuromas with ocular surface diseases

Corneal neuromas,also termed microneuromas,refer to microscopic,irregula rly-shaped enlargements of terminal subbasal nerve endings at sites of nerve damage or injury.The formation of corneal neuromas results from damage to corneal nerves,such as following corneal pathology or corneal or intraocular surge ries.Initially,denervated areas of sensory nerve fibers become invaded by sprouts of intact sensory nerve fibers,and later injured axons regenerate and new sprouts called neuromas develop.In recent years,analysis of corneal nerve abnormalities including corneal neuromas which can be identified using in vivo confocal microscopy,a non-invasive imaging technique with microscopic resolution,has been used to evaluate corneal neuropathy and ocular surface dysfunction.Corneal neuromas have been shown to be associated with clinical symptoms of discomfort and dryness of eyes,and are a promising surrogate biomarker for ocular surface diseases,such as neuropathic corneal pain,dry eye disease,diabetic corneal neuropathy,neurotrophic keratopathy,Sjogren's syndrome,bullous keratopathy,post-refra ctive surgery,and others.In this review,we have summarized the current literature on the association between these ocular surface diseases and the presentation of corneal microneuromas,as well as elaborated on their pathogenesis,visualization via in vivo confocal microscopy,and utility in monitoring treatment efficacy.As current quantitative analysis on neuromas mainly relies on manual annotation and quantification,which is user-dependent and labor-intensive,future direction includes the development of artificial intelligence software to identify and quantify these potential imaging biomarkers in a more automated and sensitive manner,allowing it to be applied in clinical settings more efficiently.Combining imaging and molecular biomarkers may also help elucidate the associations between corneal neuromas and ocular surface diseases.

Effect of corneal graft diameter on therapeutic penetrating keratoplasty for fungal keratitis

AIM: To evaluate the effect of corneal graft diameter on therapeutic penetrating keratoplasty(PKP) for fungal keratitis. METHODS: A total of 116 patients (116 eyes) suffered from fungal keratitis underwent PKP at the Affiliated Hospital of Medical College Qingdao University from May 2006 to May 2010. They were divided into two groups according to the corneal graft diameter. 64 eyes' corneal graft diameter was 8.00mm or larger and 52 eyes' graft diameter was smaller than 8.00mm. The follow-up time was 2 years. The postoperative visual acuity and complications were documented and compared. RESULTS: Sixty-two (96.88%) eyes and fifty (96.15%) eyes preserved eyeballs respectively in two groups. There was no statistical difference in postoperative visual acuity (P = 0.961), corneal graft dear rate (P=0.132) or the incidence of recurred fungal infection (P=0.770) between two groups. But there was a higher incidence of graft rejection (P=0.020) and secondary glaucoma (P=0.039) in group with corneal graft diameter 8.00mm or larger. CONCLUSION: PKP is an effective treatment approach for fungal keratitis. There is a higher incidence of complications in large-diameter PKP for fungal keratitis.Effective, preventive and therapeutic measures can improve the prognosis.

Graft rejection after deep anterior lamellar keratoplasty in fellow eye in macular corneal dystrophy: a case report

Because of the low incidence of immunological rejection,deep anterior lamellar keratoplasty(DALK)is currently the preferred treatment for macular corneal dystrophy(MCD).However,there were few reports about whether the consistent results were obtained when performing DALK in both eyes for MCD,especially when the corneal grafts were taken from different donors.Also,there were few reports about whether the stromal graft rejection occurred typically in both eyes in MCD with DALK.This case may represent the first report of an unusual and misleading manifestation of stromal graft rejection after uneventful DALK with big bubble technique in the fellow eye in MCD.A 32-year-old healthy man with MCD underwent bilateral uneventful DALK with a big bubble technique in the left eye in January and the right eye in July,the corneal grafts were taken from different donors.There was an atypical allograft rejection that occurred in the right eye and none in the left eye;although a timely diagnosis of graft rejection revealed following aqueous determination,it could not be reversed and underwent PK finally.The purpose of this case report is to illustrate the identification of atypical allograft rejection after DALK in the fellow eye,the significance of aqueous detection in the diagnosis of graft rejection,the choosing of grafts,and the timing of bilateral corneal transplantation in patients with MCD.

Observation on ultrastructure and histopathology of cornea following femtosecond laser-assisted deep lamellar keratoplasty for acute corneal alkaline burns

AIM： To demonstrate the changes in ultrastructure and histopathology of the cornea in acute corneal alkaline burns after femtosecond laser-assisted deep lamellar keratoplasty.·METHODS： The New Zealand white rabbits treated with alkaline corneal burn were randomized into two groups,Group A（16 eyes） with femtosecond laser-assisted deep lamellar keratoplasty 24 h after burn and Group B（16 eyes）without keratoplasty as controls. All eyes were evaluated with transmission electron microscopy（TEM） at 1, 2, 3,and 4wk follow-up, then all corneas were tested by hematoxylin and eosin staining histology.· RESULTS： The corneal grafts in Group A were transparent, while those in Group B showed corneal stromal edema and loosely arranged collagen fibers. One week after treatment, TEM revealed the intercellular desmosomes in the epithelial layers and intact non-dissolving nuclei in Group A. At week 4, the center of the corneas in Group A was transparent with regularly arranged collagen fibers and fibroblasts in the stroma. In Group B, squamous cells were observed on the corneal surface and some epithelial cells were detached.· CONCLUSION： Femtosecond laser-assisted deep lamellar keratoplasty can suppress inflammatory responses, prevent toxic substance-induced injury to the corneal endothelium and inner tissues with quicker recovery and better visual outcomes.

Comparison of long-term results after manual and femtosecond assisted corneal trephination in deep anterior lamellar keratoplasty for keratoconus

AIM: To compare long-term postoperative outcomes of manual and femtosecond assisted corneal trephination in deep anterior lamellar keratoplasty(FS-DALK) for keratoconus.METHODS: In the retrospective study, 17 consecutive eyes that underwent vertical side cut incision FS-DALK and 22 eyes that underwent trephine incision DALK were collected over a 2-year period. Main measurements included postoperative uncorrected-visual acuity(UCVA), corrected distance visual acuity(CDVA), refractive sphere and cylinder, manifest refraction spherical equivalent(MRSE), flat and steep corneal keratometry(K1 and K2), endothelial cell density(ECD), and time of epithelium healing and suture removal.RESULTS: Groups were comparable for diagnosis and preoperative visual acuity. Follow-up averaged 23 mo(range, 12-36 mo). At 12 mo, the mean UCVA was better in the manual-DALK group(P=0.039), and the refractive sphere was lower in the FS-DALK group(P=0.040). MRSE between groups differed at 1, 6, and 12 mo postoperatively(P=0.047, 0.025, 0.042, respectively). Mean CDVA, cylinder, K1, K2,corneal astigmatism, ECD, and time of epithelium healing were similar between groups. Stability of MRSE, ECD, and K1 returned sooner after FS-DALK. Initial loosened suture removal time was earlier in the manual-DALK group(P=0.042) while complete suture removal time was similar(P=0.122).CONCLUSION: Manual and femtosecond assisted corneal trephination in DALK are options for advanced keratoconus. FS-DALK do not result in improved visual acuity but it is more stable during the follow-up period. FSDALK in the present form show limited benefit, so surgical design and parameters still need to be optimized and explored.

Novel technique of penetrating keratoplasty in high-risk grafts with significant corneal neovascularization

Dear Editor,We write to introduce a novel technique of penetrating keratoplasty(PK)with lower risk of graft rejection in high-risk grafts.Corneal transplantation may be required in a variety of conditions such as keratoconus,pseudophakic bullous keratopathy(PBK),and corneal scars or dystrophies[1].

Phacoemulsification in eyes with corneal opacities after deep anterior lamellar keratoplasty

To evaluate the maneuverability and efficacy of phacoemulsification and intraocular lens(IOL) implantation in eyes with corneal opacities after deep anterior lamellar keratoplasty(DALK), twelve eyes of 12 patients with mild to moderate corneal opacities after DALK and coexisting cataracts were analyzed retrospectively. Phacoemulsification and IOL implantation assisted with anterior capsule staining, as well as non-invasive optical fiber illumination, were performed on all eyes. No intraoperative or postoperative complications were noted. Mean corrected distance visual acuity(logMAR) improved from 1.24±0.17 to 0.73±0.22. Post-phaco intraocular pressure was maintained between 13 to 20 mm Hg in all cases throughout the follow-up period. Mean endothelial cell density decreased from 2258.42±205.94 to 1906.25±174.23 cells/mm2. Phacoemulsification and IOL implantation are safe and valid in eyes with mild to moderate corneal opacities after DALK and coexisting cataracts when assisted with anterior capsule staining and non-invasive optical fiber illumination.

Accelerated versus standard corneal cross linking in the treatment of ectasia post refractive surgery and penetrating keratoplasty: a medium term randomized trial

AIM: To compare the clinical outcomes of the standard corneal cross linking(CXL) and the accelerated CXL in patients with progressive corneal ectasia post refractive surgery and penetrating keratoplasty.METHODS: Totally 120 eyes of 83 patients scheduled to receive either standard CXL(3 m W/cm^2 for a period of 30 min) or accelerated CXL(18 m W/cm2 for a period of 5 min). The main outcomes for comparison were the change in: maximum-K reading(K-max), manifest refractive spherical equivalent(SE), central corneal thickness(CCT), and the best corrected distance visual acuity(CDVA).RESULTS: One hundred and eleven eyes completed the study. The main outcome measurement was the K-max reading. Both group showed significant improvement in the value postoperatively at 6 and 12 mo. The mean change in the standard group was 1.21±0.11 D and in the accelerated group was 0.90±0.05 D at the end of 12 mo postoperatively, with no statistically significant difference between the 2 groups. Similarly, CDVA improved significantly from their preoperative value in the standard group by 2.98±0.11 letters, and in the accelerated group by 2.20±0.06 letters, with no statistically significant difference between the two groups. Both of the SE, and CCT showed no statistically significant difference at the end of follow up period in each group.CONCLUSION: Both standard CXL and accelerated CXL are safe and effective treatment in halting ectasia after corneal refractive surgery. The accelerated CXL results are comparable to the standard CXL with short time exposure of the cornea to ultraviolet irradiation, leading to reduced operation time, reduced operative ocular discomfort, and corneal haze.

Combine deep lamellar endothelial keratoplasty and anterior lamellar keratoplasty with limbal allograft for severe corneal injury:a case report

Dear Editor,I am Dr.Yi Liu from Department of Ophthalmology,Nanjing Hospital of Chinese Medicine Affiliated to Nanjing University of Chinese Medicine,Nanjing,China.I write to present a case of severe corneal acid-burn injury and describe a novel surgery namely,deep lamellar endothelial keratoplasty(DLEK)and anterior lamellar keratoplasty(ALK)with limbal allograft(LA).

Histopathologic findings of keratoconus corneas underwent penetrating keratoplasty according to topographic measurements and keratoconus severity

AIM： To investigate the histopathologic and morphological changes of the corneas with keratoconus（KC） undergoing penetrating keratoplasty（PKP） according to topographic findings and severity of KC.METHODS： The corneal tissue of 35 samples with KC was retrospectively evaluated with conventional light microscopy. Topographic and pachymetric parameters of keratoconus corneas by means of Pentacam such as mean keratometry（K） and central corneal thickness（CCT） were recorded. Severity of KC was graded according to Amsler-Krumeich classification. RESULTS： Epithelial thinning and breaks in Bowman＇s layer are the most common findings in keratoconus corneas（94.3% and 82.9% corneas, respectively）. The results revealed statistically significant higher mean K value and lower CCT in the keratoconus corneas that were affected by epithelial thinning, breaks in the Bowman＇s layer, folds in the Descemet＇s membrane, epithelial scars, breaks in Descemet＇s membrane, and stromal scars than those corneas without these findings（P〈0.05）. Moreover, those corneas with epithelial thinning, breaks in the Bowman＇s layer, folds in Descemet＇s membrane, epithelial scars, and stromal scars had significantly more severe disease than those corneas without these findings（P〈0.05）. The presence of the stromal and epithelial scars were associated with the higher KC severity, in which, respectively, 87.5% and 80.0% of the corneas with stromal and epithelial scars had stage 4 of the KC severity. CONCLUSION： It seems that there are some specific patterns in histologic changes of the keratoconus corneas. The presence of pathologic findings was correlatedwith thinner and steeper corneas. Epithelial or stromal scars were associated with the highest disease severity. The description of histopathologic findings of KC may help in elucidating the pathogenesis of the disease and help pathologist in differentiating KC from other corneal diseases.

Small-diameter acellular porcine corneal stroma for peripheral corneal ulceration treatment

AIM:To evaluate the clinical efficacy of small-diameter acellular porcine corneal stroma(SAPS)for the treatment of peripheral corneal ulceration(PCU).METHODS:This retrospective clinical study included 18 patients(18 eyes)with PCU between April 2018 and December 2020.All patients had PCU and underwent lamellar keratoplasty with SAPS.Observation indicators included preoperative and postoperative best-corrected visual acuity(BCVA)and transparency of SAPS.The infection control rate in the surgical eye-lesion area was also calculated.RESULTS:Eighteen patients underwent lamellar keratoplasty with SAPS to treat PCU.None of the patients experienced rejection after 6mo(18/18)and 12mo(16/16)of follow-up.The BCVA(0.47±0.30)at the 6mo followup after operation was significantly improved compared with the baseline(0.99±0.80),and the difference was statistically significant(Z=-3.415,P<0.05).The BCVA at the 12mo follow-up after operation was not statistically significant compared to the 6mo(Z=0,P=1).With time,the SAPS graft gradually became transparent.At the 6mo(18/18)and 12mo(16/16)follow-up,none of the patients had recurrent corneal infection.CONCLUSION:SAPS is clinically effective in the treatment of PCU,improving the patient’s BCVA and reducing the incidence of rejection after keratoplasty.

Acute corneal graft rejection following photorefractive keratectomy for post-penetrating keratoplasty high astigmatism

Dear Editor,We present an unusual case of acute graft rejection after photorefractive keratectomy(PRK),performed to correct high residual astigmatism after penetrating keratoplasty(PKP)for keratoconus.The primary measures of success for PKP are visual acuity,refractive outcomes。