Keratoplasty Research Articles

Turning Loss into Legacy: Opportunities for Tissue and Eye Donation in Community Hospice/Palliative Care.

Turning Loss into Legacy: Opportunities for Tissue and Eye Donation in Community Hospice/Palliative Care.

Comparison of autologous serum and platelet-rich plasma in the treatment of severe dry eye and persistent epithelial defects

PurposeTo compare the efficacy of topical autologous serum and platelet-rich plasma (PRP) in patients with severe dry eye and persistent epithelial defects. MethodsSixty-seven eyes of 42 patients including 12 Sjogren, 11 meibomian gland dysfunction, 8 post penetrating keratoplasty, 5 acne rosacea, 5 chemical burn and 3 neurotophic keratopathy were analyzed. Best corrected visual acuity, Schirmer, Ocular Surface Disease Index (OSDI), tear break-up time, Oxford staining scores were measured before the treatment and 1 month. One month scores of two groups were compared. ResultsThirty three eyes received autologous serum and 34 received PRP. There was no statistically significant differences between two groups in ocular surface parameters at baseline. Statistically significant improvements were achieved in both groups in all parameters at 1 month (p < 0.05). Schirmer score improved from 7.9 ± 7.6 to 10.6 ± 8.4 mm in autologous serum (p < 0.001) and from 10.9 ± 9.5 to 13.3 ± 10.1 in PRP (p < 0.001); BUT from 4.3 ± 2.7 to 6.7 ± 3.4 s (p < 0.001) and 4.5 ± 3.0 to 6.0 ± 3.6 (p < 0.001); OSDI from 47.7 ± 14.7 to 25.7 ± 11.0 (p < 0.001) and from 54.1 ± 17.3 to 26.8 ± 11.0 (p < 0.001); Oxford score from 4.0 ± 1.0 to 1.3 ± 1.1 in (p < 0.001) and 3.9 ± 0.9 to 1.6 ± 1.3 (p < 0.001) respectively. Significant visual improvement was achieved with PRP from 0.81 ± 0.73 LogMAR to 0.72 ± 0.63 (p = 0.025), whereas insignificant with serum from 0.60 ± 0.65 to 0.57 ± 0.67 (p = 0.147). Mean epithelial healing time was 6.7 ± 4.7 (2–14) days in serum and 3.6 ± 1.9 (2–7) in PRP (p = 0.195). ConclusionsBoth treatments are equally effective in severe dry eye and persistent epithelial defects. Although, visual gain is higher in PRP, autologous serum may be preferable due to low cost.

First Case of Interstitial Keratitis Secondary to Anaplasma phagocytophilum Infection

Purpose: To describe the first case of interstitial keratitis (IK) secondary to Anaplasma phagocytophilum infection. Methods: We present a case of IK secondary to A. phagocytophilum infection diagnosed using nested polymerase chain reaction. Results: A 32-year-old man with an unremarkable medical history presented with a 6-month history of bilateral decreased vision and ocular redness associated with a progressively enlarging white spot in the left eye. The patient was diagnosed with bilateral IK, and a thorough systemic workup was performed. The final diagnosis of A. phagocytophilum was made based on whole-blood Nested-PCR. Doxycycline was initiated with 100-mg BID tablets for 3 weeks. On completion of oral treatment, a left penetrating keratoplasty was performed. The excised cornea showed infiltration of inflammatory cells and scar tissue as well as superficial and deep stromal neovascularization. Conclusions: A. phagocytophilum is an underdiagnosed entity, and IK may be associated with its clinical manifestations. We hope that this illustration of a rather atypical finding adds to the clinical spectrum of ophthalmic conditions that can be observed in association with the disease.

Long-Term Follow-Up of Pediatric Excimer Laser-Assisted Penetrating Keratoplasty for Congenital Stromal Corneal Dystrophy.

The purpose of this study was to highlight characteristic clinical and microscopic findings and report the long-term follow-up of pediatric excimer laser-assisted penetrating keratoplasty (excimer-PKP) for congenital stromal corneal dystrophy (CSCD). A 2-year-old Greek child presented with CSCD at our department. Clinical examination showed bilateral flake-like whitish corneal opacities affecting the entire corneal stroma up to the limbus. Genetic testing identified a mutation of the decorin gene (c.962delA). The variant was not present in the parents and represented a de novo mutation. The uncorrected visual acuity was 20/100 in both eyes. Excimer-PKP (8.0/8.1 mm) was performed on the right eye at the age of 2.5 years and on the left eye at the age of 3 years. Postoperatively, alternating occlusion treatment was performed. The light microscopic examination demonstrated a disorganized extracellular matrix of the corneal stroma characterized by a prominent irregular arrangement of stromal collagen lamellae with large interlamellar clefts containing ground substance, highlighted by periodic acid-Schiff- and Alcian blue-positive reaction detecting acid mucopolysaccharides. Electron microscopy showed disorganization and caliber variation of collagen lamellae and thin filaments within an electron-lucent ground substance. The postoperative course was unremarkable. Both grafts remained completely clear 14 years postoperatively. Corneal tomography showed moderate regular astigmatism with normal corneal thickness. The corrected distance visual acuity was 20/25 in both eyes. Excimer-PKP for CSCD might be associated with excellent long-term results and a good prognosis, particularly when the primary surgery is performed at a very young age. However, this requires close postoperative follow-up examinations by an experienced pediatric ophthalmologist to avoid severe amblyopia.

Indications and Surgical Techniques for Corneal Transplantation in Mansoura Ophthalmic Center. A 4 years retrospective analytic study

Indications and Surgical Techniques for Corneal Transplantation in Mansoura Ophthalmic Center. A 4 years retrospective analytic study

Ten-year incidence of keratoconus in relation to sex, age, and thyroid gland dysfunction: a nationwide population-based cohort study (2009-2018).

Keratoconus is a corneal ectatic disorder that often leads to visual impairment and may require corneal transplantation. However, its age and gender-based incidence and potential association with thyroid gland dysfunction (TGD) remain poorly understood. This study aims to clarify these aspects and investigate the possible connection between keratoconus and TGD. We conducted a nationwide population-based cohort study using data from the Korean National Health Insurance Service database. A retrospective chart review was conducted on 4,059,021 patients aged over 20 without underlying corneal diseases in 2009. The end of the review period was at ten years, or until the onset of keratoconus. To evaluate the association with TGD, multivariate Cox regression analysis was used with adjustment of confounding variables such as sex and age. During the review period, 2,334 patients developed keratoconus before the 10-year mark. Females exhibited a higher keratoconus incidence (7.101 per 100,000 person-years) compared to males (5.559) (P<0.001). After adjusting for age, the hazard ratio (HR) for keratoconus was 1.295 times higher [95% confidence interval (CI): 1.193-1.406] in females compared to males. Age groups were stratified in 10-year intervals. The highest incidence of keratoconus was observed in the 20 to 29-year age group (10.695 per 100,000 person-years). All other age groups had significantly lower HR values, with the lowest at 50-59 years (0.508, 95% CI: 0.447-0.577). Keratoconus incidence per 100,000 person-years was 6.227 in subjects without TGD, 6.019 in the hypothyroidism group and 8.287 in the hyperthyroidism group, respectively. Although not statistically significant, individuals with hyperthyroidism showed a higher HR (1.290, 95% CI: 0.939-1.771) for keratoconus when compared to those without TGD, after adjusting for age and sex. This study emphasizes a female predominance in keratoconus incidence and suggests a possible connection between hyperthyroidism and keratoconus. Furthermore, it affirms a higher incidence of keratoconus among young individuals.

Unveiling the landscape of post-keratoplasty keratitis: a comprehensive epidemiological analysis in a tertiary center.

The present study aimed to epidemiologically evaluate patients with infectious keratitis following corneal transplantation. This retrospective study analyzed medical records of patients who underwent keratoplasty from March 2014 to March 2022 at a tertiary center. A total of seventy-five patients were evaluated. The data were classified based on culture results, the type of microorganisms involved, treatment requirements, and the type of primary keratoplasty performed. Seventy-five patients were evaluated in this study, with a mean age of 45.9years (22-95years). The mean duration between the first surgery and the incidence of infectious keratitis was 1.43years, and most cases occurred in the first year (56.2%). Bacterial and fungal keratitis in 2.17%, 1.39%, and 1.26% of cases undergoing penetrating keratoplasty (PK), endothelial keratoplasty (EK), and anterior lamellar keratoplasty (ALK) occurred, respectively. Streptococcus viridans (9.3%) and Staphylococcus aureus (6.6%) had the highest prevalence. Across various smear and culture results (gram-positive, gram-negative, fungal, and negative culture), no significant differences were found in endophthalmitis rates (P = 0.797) and the necessity for tectonic grafts (P = 0.790). Similarly, the choice of surgical method (PK, ALK, EK) showed no significant impact on the need for tectonic grafts (P = 0.45) or the rate of endophthalmitis (P = 0.55). The incidence of keratitis after a corneal graft was 1.7%, with Streptococcus viridans and Staphylococcus aureus the most common microorganisms. The rate of endophthalmitis associated with post-keratoplasty keratitis was 0.053%. There was no correlation between the necessity for a tectonic graft or the incidence of endophthalmitis and the type of microorganisms involved.

Corneal thickness and endothelial change after use of ocular hypotensive agents.

Corneal transplantation can restore visual function when visual impairment is caused by a corneal disease. However, this treatment is associated with the scarcity of cornea donors. The suitability of corneal donation from patients with glaucoma using ocular hypotensive agents (OHAs) is controversial. This study aimed to elucidate changes in corneal thickness, corneal endothelial cell density, and corneal endothelial cell hexagonality after OHA use in patients with primary open-angle glaucoma. We retrospectively reviewed the data of 53 glaucoma suspect eyes without OHA use and 106 primary open-angle glaucoma eyes under OHA use. All participants underwent corneal parameter assessment using SP-3000P (Topcon Corp., Tokyo, Japan) at the time of diagnosis and the final visit. The OHA dose and timing of use were recorded. The ocular hypotensive agents score (OHAS) was determined based on the number, formula, frequency, and duration of OHA use. Baseline data showed no significant differences between the two groups with and without OHA use. At the final visit, the OHA-treated group showed significantly lower corneal thickness and corneal endothelial cell density than those of the control group. A weak positive correlation between the OHAS and changes in corneal endothelial cell hexagonality was noted. However, no correlation was observed between the OHAS and changes in corneal thickness or endothelial cell density. In conclusion, patients with glaucoma and using OHAs should undergo the corneal structural properties examinations before donation to ensure the quality of donor cornea.

Demographic and Systemic Risk Factors for Persistent Corneal Edema Following Cataract Surgery in Patients With and Without Diabetes

PurposeTo identify risk factors associated with the development of corneal edema (CE) and the need for corneal transplantation following cataract surgery. DesignRetrospective cohort study. MethodsSetting: Nation-wide sample of Medicare beneficiaries from 2011-2015. Study PopulationMedicare beneficiaries aged over 65 years who received cataract surgery between 2011-2014 with at least 1 year of continuous follow-up. Data was retrieved from the Denominator and Physician Supplier Part B file from the Center for Medicare and Medicaid Services. Main Outcome(s) and Measure(s)The main outcome was the association between demographic characteristics (e.g. age, sex, race/ethnicity) and systemic factors including diabetes status, hypertension, and tobacco use on the incidence of CE and the subsequent need for corneal transplantation following cataract surgery. ResultsAmong 187,746 beneficiaries, 67,734 had diabetes and 120,012 did not. Beneficiaries with diabetes were more likely to develop CE compared to those without (Odds ratio [OR] 1.19, 95% Confidence Interval [CI] [1.02-1.40]). Compared to those aged 65-74, beneficiaries aged 75-84 and over 85 were more likely to develop CE (OR 1.29 [1.09-1.52]) and OR 1.96 [1.55-2.46], respectively). Asian (OR 2.42 [1.66-3.40]), Hispanic (OR 2.60 [1.73-3.74]), and North American Native (OR 3.59 [1.78-6.39]) race was associated with increased likelihood of developing CE. North American Native beneficiaries had higher risk of requiring corneal transplantation compared to White beneficiaries (OR 9.30 [2.26-25.31]). Female sex decreased likelihood of requiring corneal transplantation post-operatively (OR 0.56 [0.36-0.87]). Amongst those with diabetes, the presence of proliferative diabetic retinopathy increased the likelihood of developing CE (OR 1.94 [1.05-3.39]). ConclusionOlder age, diabetes, and non-White race elevate the risk of CE following cataract surgery, with race incurring the highest risk. Further research is needed to understand the factors underlying the significantly increased risk of CE in racial and ethnic minorities within the United States.

Keratoplasty - an Overview of the Methods and their Perioperative Management

Corneal transplantation can be divided into two groups: penetrating and lamellar keratoplasty. Newer minimally invasive procedures have emerged over the years, to improve the visual outcome and reduce complications. This article summarizes the different procedures, their indications and complications, and outlines the pre-, peri- and postoperative management in a clinical setting.Corneal transplantation is the most commonly performed transplantation of donor tissue in modern medicine. In the last years a shift away from penetrating keratoplasty (PK) towards minimally invasive lamellar operative techniques, associated with less complications, can be observed. The Descemet membrane endothelial keratoplasty (DMEK) is used to treat endothelial corneal pathologies and has overtaken the PK to become the most commonly performed form of keratoplasty. Preparation and identification of possible risk-factors are essential preoperative steps to reduce peri- and postoperative complications of keratoplasties. If corneal graft rejection occurs, early and maximum therapy is crucial for graft survival. Laser-assisted techniques offer different advantages in lamellar and penetrating keratoplasty but are not very cost-efficient.

Treatment-resistant hiccups during general anesthesia possibly caused by remimazolam: a case report

BackgroundPrevious reports have described hiccups during general anesthesia that were possibly induced by drugs, including benzodiazepines. However, there are few reports of hiccups caused by remimazolam.Case presentationA 75-year-old woman underwent corneal transplantation under general anesthesia with remimazolam. She presented with hiccups once the effects of muscle relaxants used during induction wore off, which persisted even after various treatments, such as the administration of antipsychotic drugs. However, when remimazolam administration was terminated after surgery to awaken the patient, the hiccups stopped and did not recur after extubation. Evaluation of predicted blood levels of remimazolam suggests that higher levels of remimazolam might cause hiccups.ConclusionRemimazolam might induce hiccups during general anesthesia. Anesthesiologists should consider administering muscle relaxants or changing the anesthetic in cases of refractory hiccups under general anesthesia.

Cutaneous Lagenidium deciduum infection in a patient with relapsed acute myeloid leukemia

BackgroundLagenidium deciduum is an oomycete that can cause infections in mammals that present similarly to pythiosis and mucormycosis. Most of the existing case reports have occurred in canines and have been fatal. In animals, medical therapy has not been successful, so surgical excision is the mainstay of treatment. Lagenidium sp. infections in humans are rare. There is only one case of a human Lagenidium sp. infection in the literature, and it presented as an ocular infection. The human ocular infection was resistant to medical therapy and required a penetrating keratoplasty for cure. Additional reports of effective therapy are needed to guide management of this emerging pathogen. We present the first case of a cutaneous Lagenidium deciduum infection in a human patient, which is also the first documented case of a Lagenidium deciduum infection in an immunocompromised host of any species.Case presentationAn 18-year-old female with relapsed acute myeloid leukemia, awaiting a haploidentical stem cell transplant, presented with erythematous cutaneous lesions on her left hip and bilateral buttocks that enlarged and blackened over several days. About 1 week later, boil-like lesions appeared on her bilateral buttocks. The skin lesions were initially presumed to be bacterial in origin, so the patient was treated with clindamycin and cefepime with little improvement. Upon further investigation, fungal cultures and skin biopsies revealed aseptate hyphae, so the patient was switched to isavuconazole and amphotericin B due to concern for mucormycosis. Phenotypic characterization and DNA sequencing were performed by the Fungus Testing Laboratory, University of Texas Health Science Center at San Antonio, which identified the causal fungal organism as Lagenidium deciduum. All of her cutaneous lesions were surgically excised, and the patient was treated with micafungin, terbinafine, doxycycline, and azithromycin. Micafungin and terbinafine were continued until she achieved engraftment post-transplant.ConclusionsWe report the first successful treatment of a human Lagenidium infection in an immunocompromised host through a combination of aggressive surgical excision and prolonged antifungal therapy during the prolonged neutropenia associated with allogeneic stem cell transplant. Prompt diagnosis and management may prevent disseminated oomycosis.

Alginate Hydrogel Integrated with a Human Fibroblast-Derived Extracellular Matrix Supports Corneal Endothelial Cell Functionality and Suppresses Endothelial-Mesenchymal Transition.

Human corneal transplantation is still the only option to restore the function of corneal endothelial cells (CECs). Therefore, there is an urgent need for hCEC delivery systems to replace the human donor cornea. Here, we propose an alginate hydrogel (AH)-based delivery system, where a human fibroblast-derived, decellularized extracellular matrix (ECM) was physically integrated with AH. This AH securely combined with the ECM (ECM-AH) was approximately 50 μm thick, transparent, and permeable. The surface roughness and surface potential provided ECM-AH with a favorable microenvironment for CEC adhesion and growth in vitro. More importantly, ECM-AH could support the structural (ZO-1) and functional (Na+/K+-ATPase) markers of hCECs, as assessed via western blotting and quantitative polymerase chain reaction, which were comparable with those of a ferritic nitrocarburizing (FNC)-coated substrate (a positive control). The cell density per unit area was also significantly better with ECM-AH than the FNC substrate at day 7. A simulation test of cell engraftment in vitro showed that hCECs were successfully transferred into the decellularized porcine corneal tissue, where they were mostly alive. Furthermore, we found out that the endothelial-mesenchymal transition (EnMT)-inductive factors (Smad2 and vimentin) were largely declined with the hCECs grown on ECM-AH, whereas the EnMT inhibitory factor (Smad7) was significantly elevated. The difference was statistically significant compared to that of the FNC substrate. Moreover, we also observed that TGF-β1-treated hCECs showed faster recovery of cell phenotype on the ECM. Taken together, our study demonstrates that ECM-AH is a very promising material for hCEC culture and delivery, which endows an excellent microenvironment for cell function and phenotype maintenance.

Awareness and attitudes towards eye donation among medical and allied health students in Jeddah, Saudi Arabia.

Many national studies in Saudi Arabia have revealed a lack of knowledge about eye donation. The current study assessed awareness and attitudes towards eye donation among health faculty students in Jeddah, Saudi Arabia. It aims to increase their awareness as future healthcare providers are expected to raise general awareness to attain more local corneal donations. A cross-sectional study including 1,060 health faculty students was conducted at King Abdulaziz University. Data were collected through an online questionnaire that covered participants' demographics, academic year, knowledge, and attitudes regarding eye donation. Thirty-five percent of students had heard about eye donation, with the most common sources of information being social media (29%) and health workers (24%). Most respondents, 61% (n = 643), indicated willingness to donate their eyes after death. Of these respondents, 93% (n = 986), 6.8% (n = 72), and 0.2% (n = 2) had poor, fair, and good knowledge levels, respectively. A total of 66% (n = 696) and 34% (n = 364) had negative and positive attitudes, respectively. Students in this study showed low levels of knowledge and negative attitudes about eye donation. Students should be adequately educated about the significance of eye donation.

Descemet membrane endothelial keratoplasty and penetrating keratoplasty in pseudophakic bullous keratopathy: comparison of visual outcomes, graft survival rates, and complications

Objective: To compare the outcomes of Descemet Membrane Endothelial Keratoplasty (DMEK) and Penetrating Keratoplasty (PK) in patients with pseudophakic bullous keratopathy (PBK). Methods: Records of 51 eyes of 51 PBK patients (32 male, 19 female) who underwent PK (Group1=38 eyes) and DMEK (Group 2=13 eyes) were reviewed retrospectively. The two groups were compared for Best-corrected visual acuity (BCVA), graft survival rates, and complications. Results: The mean age was 69.1 and 67.1 years in group 1 and group 2, respectively. First-year cumulative survival rates for group 1 and group 2 were 92.1% and 61.5%, respectively, and 89.1% and 51.3% in the second year (P=0.001 by log-rank test). At the last follow-up visit, 2.7% of Group 1 and 30.8% of Group 2 had a BCVA of 0.3 or better (P=0.004). Graft failure was observed in 12 eyes (31.6%) in group 1 and 8 eyes (61.5%) in group 2 (P=0.056). At the last examination, the rates of transparent grafts were 73.7% and 69.2% in group 1 and group 2, respectively (P=0.756). Postoperative glaucoma was observed in 4 eyes (30.8%) in the group 2 and 4 eyes (10.5%) in the group 1 (P=0.083). There was no significant difference between the two groups regarding other complications (P&gt;0.05). Conclusions: DMEK surgery offers a better visual outcome than PK for the treatment of PBK. Careful follow-up of patients is required in terms of glaucoma and graft failure after DMEK. Although the graft survival rate was lower in the DMEK group, a similar rate of graft transparency was achieved at the final examination with repeated DMEK surgery.

Outcomes after reversed corneal graft rejection: a report from the European VISICORT project

ObjectiveThis study aims to describe the outcome of corneal grafts, both low risk and high risk, after successfully reversed immunological rejection.MethodsDatasets on reversed rejection episodes in penetrating and endothelial keratoplasties...

Clinical, microbiologic, and treatment outcomes of dematiaceous fungal keratitis - A retrospective study.

Dematiaceous fungi, the third most common causative organism of fungal keratitis, constitute 3.5% to 43.5% of fungal keratitis worldwide. Several studies on filamentous fungi (Aspergillus and Fusarium) are available as opposed to that on dematiaceous fungal keratitis. This study aims to describe the profile of dematiaceous fungal keratitis in South India. This institutional cohort study on culture-proven dematiaceous fungal keratitis was performed in a single ophthalmology referral center in South India for a 6-year period. Records were analyzed for demographic, clinical, microbiological, and treatment outcomes for 3 months from the date of presentation. This study comprised 312 cases involving dematiaceous fungal keratitis (DFK). During the study period, DFK accounted for 10% of microbial keratitis and 24.6% of fungal keratitis cases. The mean (standard deviation) age was 54 (14) years. Males were commonly affected (73.4%). Keratitis was ≤1/3rd depth in 47.8% of cases. Fifty-four cases (17.3%) demonstrated surface pigmentation, and 69 cases (22.1%) had endothelial plaque. Curvularia spp. (99 eyes, 31.7%) was the most common fungal isolate among the speciated fungi. Topical medications resulted in the healing of 63.5% of cases. A total of 193 cases (79%) healed, and 49 cases had to undergo therapeutic penetrating keratoplasty (TPK). Early TPK was performed for 20 cases (40.8%). Seventeen eyes (34.6%) maintained clear grafts at the end of 3 months. In this extensive study on DFK, we report a high incidence of this group of fungal keratitis. We found an excellent healing rate in our cohort of patients.

Corneal collagen cross-linking in patients with keratoconus from the Dresden protocol to customized solutions: theoretical basis.

Keratoconus is an ectatic condition characterized by gradual corneal thinning, corneal protrusion, progressive irregular astigmatism, corneal fibrosis, and visual impairment. The therapeutic options regarding improvement of visual function include glasses or soft contact lenses correction for initial stages, gas-permeable rigid contact lenses, scleral lenses, implantation of intrastromal corneal ring or corneal transplants for most advanced stages. In keratoconus cases showing disease progression corneal collagen crosslinking (CXL) has been proven to be an effective, minimally invasive and safe procedure. CXL consists of a photochemical reaction of corneal collagen by riboflavin stimulation with ultraviolet A radiation, resulting in stromal crosslinks formation. The aim of this review is to carry out an examination of CXL methods based on theoretical basis and mathematical models, from the original Dresden protocol to the most recent developments in the technique, reporting the changes proposed in the last 15y and examining the advantages and disadvantages of the various treatment protocols. Finally, the limits of non-standardized methods and the perspectives offered by a customization of the treatment are highlighted.

Utility of artificial intelligence in the diagnosis and management of keratoconus: a systematic review.

The application of artificial intelligence (AI) systems in ophthalmology is rapidly expanding. Early detection and management of keratoconus is important for preventing disease progression and the need for corneal transplant. We review studies regarding the utility of AI in the diagnosis and management of keratoconus and other corneal ectasias. We conducted a systematic search for relevant original, English-language research studies in the PubMed, Web of Science, Embase, and Cochrane databases from inception to October 31, 2023, using a combination of the following keywords: artificial intelligence, deep learning, machine learning, keratoconus, and corneal ectasia. Case reports, literature reviews, conference proceedings, and editorials were excluded. We extracted the following data from each eligible study: type of AI, input used for training, output, ground truth or reference, dataset size, availability of algorithm/model, availability of dataset, and major study findings. Ninety-three original research studies were included in this review, with the date of publication ranging from 1994 to 2023. The majority of studies were regarding the use of AI in detecting keratoconus or subclinical keratoconus (n=61). Among studies regarding keratoconus diagnosis, the most common inputs were corneal topography, Scheimpflug-based corneal tomography, and anterior segment-optical coherence tomography. This review also summarized 16 original research studies regarding AI-based assessment of severity and clinical features, 7 studies regarding the prediction of disease progression, and 6 studies regarding the characterization of treatment response. There were only three studies regarding the use of AI in identifying susceptibility genes involved in the etiology and pathogenesis of keratoconus. Algorithms trained on Scheimpflug-based tomography seem promising tools for the early diagnosis of keratoconus that can be particularly applied in low-resource communities. Future studies could investigate the application of AI models trained on multimodal patient information for staging keratoconus severity and tracking disease progression.

Recurrence Characteristics on Optical Coherence Tomography and Treatments of Reis-Bücklers Corneal Dystrophy After Phototherapeutic Keratectomy or Penetrating Keratoplasty

PurposeTo evaluate the recurrence characteristics on optical coherence tomography and clinical outcomes after phototherapeutic keratectomy (PTK) or penetrating keratoplasty (PKP) in patients with Reis-Bücklers corneal dystrophy (RBCD). DesignRetrospective interventional case series. MethodsSeventeen patients with RBCD (31 eyes, including six surgery-naïve eyes and 25 surgical eyes) received 44 surgical interventions from 1996 through 2022. PTK or PKP was performed as the initial surgical procedure. Significant recurrence was determined when best spectacle-corrected visual acuity decreased at least two lines with increased opacity in the superficial cornea. Repeated PTK or PTK on the corneal graft (CG-PTK) was considered if patients could not endure poor vision due to significant recurrence. Recurrence depth and annual increase in thickness of the central cornea and subepithelial deposits were assessed by anterior segment optical coherence tomography. ResultsThe mean follow-up time was 12.8±8.5 years (range, 2.0–25.5 years). The mean logMAR best spectacle-corrected visual acuity improved from 1.24±0.48 preoperatively to 0.27±0.09 postoperatively in the initial PTK group (13 eyes, P<0.001), from 1.84±0.69 to 0.40±0.13 in the PKP group (12 eyes, P<0.001), from 1.04±0.46 to 0.30±0.07 in the repeated PTK group (12 times in 7 eyes, P<0.001), and from 1.29±0.43 to 0.39±0.11 in the CG-PTK group (7 times in 5 eyes, P=0.001). The median significant recurrence time was 27 months (95% confidence interval 23.9-30.1), 96 months (84.1-107.9), 31 months (28.8-33.1), and 24 months (19.8-28.2), respectively (P<0.001). The depth of superficial deposits located between the epithelium and the anterior stroma was approximately 115μm (85-159μm). The annual thickening of subepithelial deposits was 14±2μm after initial PTK, 7±3μm after PKP, 14±3μm after repeated PTK, and 30±11μm after CG-PTK, compared to 4±2μm in surgery-naïve eyes (P=0.002, 0.515, 0.002, <0.001). The thickness of the central cornea increased by 15±2μm, 7±2μm, 15±3μm, and 31±10μm per year in the four surgery groups, respectively, compared to 5±2μm in surgery-naïve eyes (P=0.001, 0.469, 0.001, <0.001). ConclusionsBetter visual acuity can be achieved after PTK than PKP for treatment of RBCD. The annual thickening of subepithelial deposits may approximate an increase in central corneal thickness. The superficial distribution of subepithelial deposits makes it feasible to perform repeated PTK, even on the corneal allograft, for recurrent RBCD.