Knowledge, Attitude and Awareness towards Corneal Donation in Aseer Region, Saudi Arabia

Background: Corneal transplantation is the mainstay procedure performed for sight restoration in patients with corneal blindness, which can be caused by infection, corneal dystrophy, degenerative disorders such as keratoconus or traumatic causes. Most corneal transplants in Saudi Arabia are performed using imported corneas. Aims: To determine the level of knowledge and awareness and the factors affecting corneal donation in Aseer region, Saudi Arabia. Subjects and Methods: A descriptive cross-sectional approach was used targeting the population of Aseer region aged 18 years and above. The data were collected using electronic self-administered questionnaire. The tool covered the participants’ biodemographic data, knowledge related questions and willingness of corneal donation and factors affecting such attitudes. Results: Of the 641 participants, 66.1% were males, 47.6% were in the age group 20 – 30 years and 19.2% claimed to have enough knowledge about corneal donation. The mean knowledge score (SD) was 2.13 (1.757) out of 8. Regarding participants’ attitude, 26.7% were willing to donate their own cornea. The willingness was significantly associated with good level of knowledge (p = 0.008). Females were more inclined to donate their corneas than males (30.9% vs 24.5%, p = 0.025). Conclusion: The study revealed a low level of knowledge of corneal donation in Aseer region, Saudi Arabia. Approximately one quarter of the participants reported willingness of corneal donation. Lack of knowledge was the main barrier, as it was reported by almost two thirds. Key words: Cornea, Donation, Awareness, Penetrating Keratoplasty, Saudi Arabia

Prediction of corneal graft rejection using central endothelium/Descemet’s membrane complex thickness in high-risk corneal transplants

To determine whether measurements of Endothelium/Descemet complex thickness (En/DMT) are of predictive value for corneal graft rejection after high-risk corneal transplantation, we conducted this prospective, single-center, observational case series including sixty eyes (60 patients) at high risk for corneal graft rejection (GR) because of previous immunologic graft failure or having at least two quadrants of stromal vascularization. Patients underwent corneal transplant. At 1st, 3rd, 6th, 9th, and 12th postoperative month, HD-OCT imaging of the cornea was performed, and the corneal status was determined clinically at each visit by a masked cornea specialist. Custom-built segmentation tomography algorithm was used to measure the central En/DMT. Relationships between baseline factors and En/DMT were explored. Time dependent covariate Cox survival regression was used to assess the effect of post-operative En/DMT changes during follow up. A longitudinal repeated measures model was used to assess the relationship between En/DMT and graft status. Outcome measures included graft rejection, central Endothelium/Descemet’s complex thickness, and central corneal thickness (CCT). In patients with GR (35%), the central En/DMT increased significantly 5.3 months (95% CI: 2, 11) prior to the clinical diagnosis of GR, while it remained stable in patients without GR. During the 1-year follow up, the rejected grafts have higher mean pre-rejection En/DMTs (p = 0.01), compared to CCTs (p = 0.7). For En/DMT ≥ 18 µm cut-off (at any pre-rejection visit), the Cox proportional hazard ratio was 6.89 (95% CI: 2.03, 23.4; p = 0.002), and it increased to 9.91 (95% CI: 3.32, 29.6; p < 0.001) with a ≥ 19 µm cut-off. In high-risk corneal transplants, the increase in En/DMT allowed predicting rejection prior to the clinical diagnosis.

Rabies encephalitis

Rabies is an almost always fatal disease that physicians and patients dread due to its dismal prognosis and limited treatment options. Transmission of this disease occurs through the bite of dogs and wild animals (like jackal in our case). Other rare forms of transmission may be through inhalation in bat-infested caves and human-to-human transmission by infected corneal transplants, solid organ and tissue transplantation, and sometimes in laboratory settings. Its diagnosis is usually clinical in the absence of availability of special laboratory investigations at the point-of-care facility. Few people have described the role of imaging in diagnosis. We hereby report a patient with rabies encephalitis, having a history of jackal bite and classical MRI findings that we can use for early diagnosis in the absence of typical clinical features and specialised diagnostic testing.

Tectonic Eccentric Penetrating Sclerokeratoplasty à chaud as Treatment for Peripheral Perforated or Predescemetal Corneal Ulceration

Background Tectonic eccentric sclerokeratoplasty à chaud is a very complex corneal operation and aims to preserve the eyeball and possibly to improve visual acuity in patients with peripheral corneal ulcerations or perforating corneal trauma. Methods 1650 eyes received corneal transplants in our clinic between 2006 and 2019. 14 of these 1650 eyes (0.8%) had a perforated or predescemetal peripheral corneal ulceration and these were treated between 2006 and 2019 with a tectonic eccentric sclerokeratoplasty à chaud. The mean age of the 8 women and 6 men included in this case series was 63 years (22 – 91 years). Results In the postoperative follow-up period, most complications and reoperations occurred in the first 6 months. Re-ulceration was observed in 2 cases as well as early suture loosening in 12 patients. These 2 cases were treated with a partial conjunctival flap. Additionally, prolonged superficial wound healing process was shown in 12 patients. Therefore 27 amniotic membrane transplantations, 12 suture replacements, and 6 partial conjunctival flaps were performed in total. No re-keratoplasties were required in this case series. All eyes could be stabilised through the sclerokeratoplasty as well as subsequent operations and intensive local or even systemic treatment. After removal of the corneal suture, the best-corrected visual acuity improved only insignificantly to hand movement in 1 case, finger counting in 3 cases, 0.1 in 5 cases, 0.2 in 4 cases and 0.5 in 1 case. Preservation of the eyeball with pain relief was achieved in all 14 eyes. Conclusions Eccentric sclerokeratoplasty is a very demanding surgical procedure and is extremely rarely performed. The goal is to preserve the eye.

Acanthamoeba Keratitis, Pathology, Diagnosis and Treatment

Acanthamoeba keratitis is an unusual corneal infection that is recently increasing in frequency and is often contracted by contact lens wearers, someone who experienced recent eye trauma, or someone exposed to contaminated waters. Acanthamoeba survive in air, soil, dust, and water. Therefore, eye trauma and poor contact lens hygiene practices lead to the entrapment of debris and thus infection. Acanthamoeba keratitis results in severe eye pain, inflammation, and defects of the epithelium and stroma that can potentially result in vision loss if not diagnosed early and treated promptly. The disease can be diagnosed using corneal scrape/biopsy, polymerase chain reactions, impression cytology, or in vivo confocal microscopy. Once diagnosed, it is usually treated with an antimicrobial combination therapy of biguanide and aromatic diadine eye drops for several months. Advanced stages of the disease result in vision loss and the need for corneal transplants. Avoiding the risk factors and diagnosing the disease early are the most effective ways to combat Acanthamoeba keratitis.

Directed Differentiation of Human Pluripotent Stem Cells towards Corneal Endothelial-Like Cells under Defined Conditions

The most crucial function of corneal endothelial cells (CEnCs) is to maintain optical transparency by transporting excess fluid out of stroma. Unfortunately, CEnCs are not able to proliferate in vivo in the case of trauma or dystrophy. Visually impaired patients with corneal endothelial deficiencies that are waiting for transplantation due to massive global shortage of cadaveric corneal transplants are in a great need of help. In this study, our goal was to develop a defined, clinically applicable protocol for direct differentiation of CEnCs from human pluripotent stem cells (hPSCs). To produce feeder-free hPSC-CEnCs, we used small molecule induction with transforming growth factor (TGF) beta receptor inhibitor SB431542, GSK-3-specific inhibitor CHIR99021 and retinoic acid to guide differentiation through the neural crest and periocular mesenchyme (POM). Cells were characterized by the morphology and expression of human (h)CEnC markers with immunocytochemistry and RT-qPCR. After one week of induction, we observed the upregulation of POM markers paired-like homeodomain transcription factor 2 (PITX2) and Forkhead box C1 (FOXC1) and polygonal-shaped cells expressing CEnC-associated markers Zona Occludens-1 (ZO-1), sodium-potassium (Na+/K+)-ATPase, CD166, sodium bicarbonate cotransporter 1 (SLC4A4), aquaporin 1 (AQP1) and N-cadherin (NCAD). Furthermore, we showed that retinoic acid induced a dome formation in the cell culture, with a possible indication of fluid transport by the differentiated cells. Thus, we successfully generated CEnC-like cells from hPSCs with a defined, simple and fast differentiation method.

Biomaterials for corneal endothelial cell culture and tissue engineering

The corneal endothelium is the posterior monolayer of cells that are responsible for maintaining overall transparency of the avascular corneal tissue via pump function. These cells are non-regenerative in vivo and therefore, approximately 40% of corneal transplants undertaken worldwide are a result of damage or dysfunction of endothelial cells. The number of available corneal donor tissues is limited worldwide, hence, cultivation of human corneal endothelial cells (hCECs) in vitro has been attempted in order to produce tissue engineered corneal endothelial grafts. Researchers have attempted to recreate the current gold standard treatment of replacing the endothelial layer with accompanying Descemet’s membrane or a small portion of stroma as support with tissue engineering strategies using various substrates of both biologically derived and synthetic origin. Here we review the potential biomaterials that are currently in development to support the transplantation of a cultured monolayer of hCECs.