Background and Objective: Limbal stem cell deficiency (LSCD) describes the clinical condition when there is dysfunction of the corneal epithelial stem/progenitor cells and the inability to sustain the normal homeostasis of the corneal epithelium. The limbal stem cells are located in a specialized area of the eye called the palisades of Vogt (POV). There have been significant advances in the diagnosis and management of LSCD over the past decade and this review focuses on the pathophysiology of LSCD, its clinical manifestations, diagnosis, and causes.

Methods: Papers regarding LSCD were searched using PubMed to identify the current state of diagnosis and causes of LSCD published through to June 2022. 
Key Content and Findings: LSCD is clinically demonstrated by a whorl-epitheliopathy, loss of the POV, and conjunctivalization of the cornea. The diagnosis of this condition is based on clinical examination and aided by the use of impression cytology, in vivo confocal microscopy, and anterior segment optical coherence tomography (asOCT). There are many causes of LSCD, but those which are most common include chemical injuries, aniridia, contact lens wear, and Stevens-Johnson syndrome (SJS).

Conclusions: While this condition is most commonly encountered by corneal specialists, it is important that other ophthalmologists recognize the possibility of LSCD as it may arise in other co-morbid eye conditions.

The prevalence of diabetic retinopathy (DR) continues to increase in pregnant females; these individuals are also at a higher risk of disease progression. The lack of evidence regarding the safety and efficacy of current treatment options in pregnancy makes disease management particularly challenging.All pregnant women with diabetes should have a prenatal DR screening, as well as receive counseling regarding the progression and management of DR during pregnancy. Optimal blood glucose and blood pressure control should be encouraged. For patients with proliferative diabetic retinopathy (PDR) in the absence of visually significant diabetic macular edema (DME), panretinal photocoagulation (PRP) remains a safe and effective treatment option. Visually significant DME can be treated with focal laser if areas of focal leakage are identified in the macula on fluorescein angiogram, intravitreal steroids or anti-vascular endothelial growth factor (VEGF) agents, The theoretical risk of anti-VEGF agents to the fetus should be considered and the patients should be extensively counselled regarding the risks and benefits of initiating anti-VEGF therapy before initiating treatment. When the decision is made to treat with anti-VEGF agents, Ranibizumab should be the agent of choice. In conclusion, ophthalmologists should make treatment decisions in pregnant patients with DR on a case-by-case basis taking into consideration disease severity, risk of permanent threat to vision, gestational age, and patient preferences.

Background and Objective: Nearly 30 years have passed since limbal stem cell deficiency (LSCD) was first identified by pioneers and given clinical attention. LSCD remains a difficult disease to treat. It can potentially lead to blinding. At present, understanding of limbal stem cells (LSCs) has deepened and various treatment options for LSCD have been devised. The objective of this review is to summarize basic knowledge of LSCD and current treatment strategies.

Methods: PubMed search was performed to find studies published in English on LSCs and LSCD including original reports and reviews. Literatures published from 1989 to 2022 were reviewed.
Key Content and Findings: LSCs are enigmatic stem cells for which no specific marker has been discovered yet. Although LSCD is not difficult to diagnose, it is still challenging to treat. An important advancement in the treatment of LSCD is the provision of guidelines for selecting systematic surgical treatment according to the patient’s condition. It is also encouraging that stem cell technologies are being actively investigated for their potential usefulness in the treatment of LSCD.

Conclusions: Although various treatment options for LSCD have been developed, it should be kept in mind that the best chance of treatment for LSCD is in the early stage of the disease. Every effort should be made to preserve as many LSCs as possible in the early treatment of LSCD.

Background: Necrotising fasciitis (NF) is a rare but severe necrotising infection of the subcutaneous tissues. We report a case of periocular NF associated with a concurrent COVID-19 infection and explore potential mechanisms of pathogenesis of COVID-19 infection and necrotising superinfections.

Case Description: A 33-year-old previously healthy female presented with right-sided progressive periocular swelling, erythema, pain and fever, two days after sustaining a laceration to the right superolateral brow from a clenched fist. She had a concurrent COVID-19 infection, detected on nasopharyngeal polymerase chain reaction swab thirteen days prior to presentation and again at presentation. She did not have an oxygen requirement. There was a large bulbous collection of the right upper lid with fluctuance and overlying erythema, and a communicating sinus drained frank pus from the superolateral brow. Pre-operative T2-weighted MRI demonstrated fascial hyperintensity involving the pre-septal tissues and extending to the anterior temporal fossa. She was commenced on intravenous meropenem, clindamycin and vancomycin, and underwent early surgical debridement. Initial debridement demonstrated right upper lid necrosis involving the dermal and pre-septal layers, including the orbicularis, but sparing the tarsus. Streptococcus pyogenes was isolated, and she was continued on a prolonged course of intravenous antibiotic. Periocular defects were repaired with a right-sided brow adipo-fascial flap based on the supratrochlear artery, browpexy and dual full thickness skin grafts on the right upper lid and flap.

Conclusions: NF is an acute fulminant infection rarely affecting the periocular tissues. This represents a unique case of periocular NF associated with a concurrent COVID-19 infection.

Backgrounds: To assess changes in anterior segment biometry during accommodation using a swept source anterior segment optical coherence tomography (SS-OCT).

Methods: One hundred-forty participants were consecutively recruited in the current study. Each participant underwent SS-OCT scanning at 0 and ?3 diopter (D) accommodative stress after refractive compensation, and ocular parameters including anterior chamber depth (ACD), anterior and posterior lens curvature, lens thickness (LT) and lens diameter were recorded. Anterior segment length (ASL) was defined as ACD plus LT. Lens central point (LCP) was defined as ACD plus half of the LT. The accommodative response was calculated as changes in total optical power during accommodation.

Results: Compared to non-accommodative status, ACD (2.952±0.402 vs. 2.904±0.382 mm, P<0.001), anterior (10.771±1.801 vs. 10.086±1.571 mm, P<0.001) and posterior lens curvature (5.894±0.435 vs. 5.767±0.420 mm, P<0.001), lens diameter (9.829±0.338 vs. 9.695±0.358 mm, P<0.001) and LCP (4.925±0.274 vs. 4.900±0.259 mm, P=0.010) tended to decreased and LT thickened (9.829±0.338 vs. 9.695±0.358 mm, P<0.001), while ASL (6.903±0.279 vs. 6.898±0.268 mm, P=0.568) did not change significantly during accommodation. Younger age (β=0.029, 95% CI: 0.020 to 0.038, P<0.001) and larger anterior lens curvature (β=?0.071, 95% CI: ?0.138 to ?0.003, P=0.040) were associated with accommodation induced greater steeping amplitude of anterior lens curvature. The optical eye power at 0 and ?3 D accommodative stress was 62.486±2.284 and 63.274±2.290 D, respectively (P<0.001). Age was an independent factor of accommodative response (β=?0.027, 95% CI: ?0.038 to ?0.016, P<0.001).

Conclusions: During ?3 D accommodative stress, the anterior and posterior lens curvature steepened, followed by thickened LT, fronted LCP and shallowed ACD. The accommodative response of ?3 D stimulus is age-dependent.

Background: Dyop® is a dynamic optotype with a rotating and segmented visual stimulus. It can be used for visual acuity and refractive error measurement. The objective of the study was to compare refractive error measurement using the Dyop® acuity and LogMAR E charts.

Methods: Fifty subjects aged 18 or above with aided visual acuity better than 6/12 were recruited. Refractive error was measured by subjective refraction methods using the Dyop® acuity chart and LogMAR E charts and the duration of measurement compared. Thibo’s notation was used to represent the refractive error obtained for analysis.

Results: There was no significant difference in terms of spherical equivalent (M) (P=0.96) or J0 (P=0.78) and J45 (P=0.51) components measured using the Dyop® acuity and LogMAR E charts. However, subjective refraction measurement was significantly faster using the Dyop® acuity chart (t=4.46, P<0.05), with an average measurement time of 419.90±91.17 versus 452.04±74.71 seconds using the LogMAR E chart.

Conclusions: Accuracy of refractive error measurement using a Dyop® chart was comparable with use of a LogMAR E chart. The dynamic optotype Dyop® could be considered as an alternative fixation target to be used in subjective refraction.