OBJECTIVE: To examine and to understand the limbal stem-cell deficiency (LSCD) because of Steven-Johnson syndrome (SJS) in line with the new classification system for the first time in the literature.
METHODS: Medical records of patients with LSCD because of SJS were reviewed retrospectively. In addition to demographic data and ophthalmologic or systemic findings, anterior segment photographs of the patients were reviewed retrospectively. Limbal stem-cell deficiency severity was graded according to the classification published by the Limbal Stem Cell Working Group.
RESULTS: Twenty-four eyes of 14 patients with eye involvement secondary to SJS were included in the study. The mean age of the patients was 36.09±16.70 (9-58) years and the female-to-male ratio was 11:3. The anterior segment photographs of the patients were evaluated by two independent masked observers. Limbal stem-cell deficiency severity was graded according to the classification published by Deng et al. Corneal opacity was divided into three stages according to the area of involvement. Corneal opacity was classified as Stage I if the central 5 mm region of the cornea was not affected, as Stage II if the central 5 mm region of the cornea was affected, and as Stage III if the entire corneal surface was affected. Limbal involvement was classified as Stage A if it was below 50%, as Stage B if it was between 50% and 100%, and as Stage C if it was 100%.
CONCLUSIONS: This is the first study in the literature to describe and classify LSCD because of SJS, according to the new LSCD classification. Consistent with the results, LSCD follows a bimodal distribution. Most patients demonstrated severe (Stage III-32.14%) or mild (Stage IA-21.42%) LSCD.

Limbal stem cell deficiency is an ocular surface disease with the imbalance of corneal epithelial homeostasis caused by decrease of number or weakening of function of limbal stem cells. In 2019 and 2020, the international limbal stem cell deficiency working group developed and released the international consensus on the definition, classification, diagnosis, staging and management of limbal stem cell deficiency, which provided a standard protocol for related research and clinical diagnosis and treatment of limbal stem cell deficiency. In order to help Chinese ophthalmologists to properly understand its core components, there is a need to make in-depth interpretation to the key and difficult contents of the international consensus. (Chin J Ophthalmol, 2021, 57: 95-99).
角膜缘干细胞缺乏是角膜缘干细胞数量或功能下降所致角膜上皮稳态失衡性眼表疾病。国际角膜缘干细胞工作小组于2019和2020年制定并发布了有关角膜缘干细胞缺乏定义、诊断、分期和治疗的国际共识，为角膜缘干细胞缺乏的相关研究和临床诊疗工作提供了标准。为了方便我国眼科医师正确理解和掌握其核心内容，本文就国际共识中的重点和难点内容进行补充和深入解读。（中华眼科杂志，2021，57：95-99）.

OBJECTIVE: Despite extensive knowledge gained over the last 3 decades regarding limbal stem cell deficiency (LSCD), the disease is not clearly defined, and there is lack of agreement on the diagnostic criteria, staging, and classification system among treating physicians and research scientists working on this field. There is therefore an unmet need to obtain global consensus on the definition, classification, diagnosis, and staging of LSCD.
METHODS: A Limbal Stem Cell Working Group was first established by The Cornea Society in 2012. The Working Group was divided into subcommittees. Four face-to-face meetings, frequent email discussions, and teleconferences were conducted since then to obtain agreement on a strategic plan and methodology from all participants after a comprehensive literature search, and final agreement was reached on the definition, classification, diagnosis, and staging of LSCD. A writing group was formed to draft the current manuscript, which has been extensively revised to reflect the consensus of the Working Group.
RESULTS: A consensus was reached on the definition, classification, diagnosis, and staging of LSCD. The clinical presentation and diagnostic criteria of LSCD were clarified, and a staging system of LSCD based on clinical presentation was established.
CONCLUSIONS: This global consensus provides a comprehensive framework for the definition, classification, diagnosis, and staging of LSCD. The newly established criteria will aid in the correct diagnosis and formulation of an appropriate treatment for different stages of LSCD, which will facilitate a better understanding of the condition and help with clinical management, research, and clinical trials in this area.

Corneal abrasion is the most common ocular complication in surgery. Treatment requires pain control, antimicrobial prophylaxis, and close monitoring. Pain improves significantly after 24 hours and should be resolved by 48 hours. Persistent, worsening, or new symptoms warrant immediate specialist consultation. The authors review the pathophysiology of perioperative corneal abrasion, and propose updated evidence-based guidelines for improved patient care.

Data on eye irritation are generally needed for the hazard identification of chemicals. As the Bovine Corneal Opacity and Permeability (BCOP) test has been accepted by many regulatory agencies for the identification of corrosive and severe ocular irritants since September 2009 (OECD Test Guideline 437, TG 437), we evaluated this alternative method for routine testing at BASF. We demonstrated our technical proficiency by testing the reference standards recommended in TG 437, and 21 additional materials with published BCOP and in vivo data. Our results matched the published in vitro data very well, but with some intentionally selected false negatives (FNs) and false positives (FPs), the concordance was 77% (24/31), with FN and FP rates of 20% (2/10) and 24% (5/21), respectively. In addition, we tested 21 in-house materials, demonstrating the utility of the BCOP assay for our own test material panel. Histopathological assessment of the corneas by light microscopy was also conducted, as this was suggested as a means of improving the identification of FNs. The histopathology corrected the classification of some FNs, but also increased the number of FPs. Parallel to the test method evaluation, we compared three new opacitometer models with the current standard device. We recommend the use of an opacitometer developed in our BASF laboratory, which has certified components and electronic data storage, resulting in what we consider to be excellent sensitivity, stability and reproducibility.