ABSTRACT
The corneal epithelium (CE) is the outermost layer of the cornea with constant turnover, relative stability, remarkable plasticity, and compensatory properties to mask alterations in the underlying stroma. The advent of quantitative imaging modalities capable of producing epithelial thickness mapping (ETM) has made it possible to characterize better the different patterns of epithelial remodeling. In this comprehensive synthesis, we reviewed all available data on ETM with different methods, including very high-frequency ultrasound (VHF-US) and spectral-domain optical coherence tomography (SD-OCT) in normal individuals, corneal or systemic diseases, and corneal surgical scenarios. We excluded OCT studies that manually measured the corneal epithelial thickness (CET) (e.g., by digital calipers) or the CE (e.g., by confocal scanning or handheld pachymeters). A comparison of different CET measuring technologies and devices capable of producing thickness maps is provided. Normative data on CET and the possible effects of gender, aging, diurnal changes, refraction, and intraocular pressure are discussed. We also reviewed ETM data in several corneal disorders, including keratoconus, corneal dystrophies, recurrent epithelial erosion, herpes keratitis, keratoplasty, bullous keratopathy, carcinoma in situ, pterygium, and limbal stem cell deficiency. The available data on the potential role of ETM in indicating refractive surgeries, planning the procedure, and assessing postoperative changes are reviewed. Alterations in ETM in systemic and ocular conditions such as eyelid abnormalities and dry eye disease and the effects of contact lenses, topical medications, and cataract surgery on the ETM profile are discussed.
ABSTRACT
Purpose: To investigate the choroidal structure in keratoconic patients with different severity using the choroidal vascularity index (CVI) derived from image binarization on enhanced depth imaging optical coherence tomography scans (EDI-OCT). Methods: Sixty-eight eyes from 34 keratoconus (KCN) patients and 72 eyes from 36 healthy subjects were recruited in this prospective, noninterventional, comparative cross-sectional study. EDI-OCT was employed to measure choroidal parameters, including choroidal thickness (CT), total choroidal area (TCA), luminal area, stromal area, and CVI. Results: Subfoveal CT was 354.6 ± 66.8 µm in the control group and 371 ± 64.5 µm in the KCN group (P = 0.86). There was no significant difference between control and KCN groups in terms of TCA (0.66 ± 0.14 mm2 vs. 0.7 ± 0.12 mm2; P = 0.70), luminal area (0.49 ± 0.10 mm2 vs. 0.53 ± 0.08 mm2; P = 0.67), and stromal area (0.16 ± 0.05 mm2 vs. 0.17 ± 0.05 mm2; P = 0.84). CVI was also comparable in the control group (75.4% ±3.4%) and the KCN group (75.6% ±4.5%; P = 0.43). There was also no significant correlation between other choroidal parameters and KCN severity indices. Conclusion: It seems that CVI as well as other choroidal biomarkers were not significantly different between patients with KCN and healthy subjects.
ABSTRACT
BACKGROUND: Glaucoma is one of the main causes of irreversible blindness. The most common type of glaucoma is primary open angle glaucoma (POAG). TGF-ß2, the main TGF-ß isoform in the eye, is critical for extracellular matrix production and angiogenesis. Genetic studies have shown that TGF-ß2 gene (TGFB2) polymorphisms affect its expression in the eye. The aim of this study was to investigate the presence of the TGFB2 rs991967 polymorphism in POAG, and the effect of this polymorphism on clinical characteristics in POAG patients. METHODS: This case-control study was conducted on 112 control participants and 112 POAG patients referred to Khatam-Al-Anbia Eye Hospital, Mashhad, Iran. The TGFB2 rs991967 polymorphism was genotyped by the PCR-restriction fragment length polymorphism (PCR-RFLP) method. The genotyping results and clinical findings were analyzed using SPSS version 16. RESULTS: The most common genotype was AA, observed in 54.5% of the patients (P < 0.0001, OR 12.2, CI 95% for OR: 5.25 to 28.31). Moreover, the highest and lowest frequencies of the mutant A allele were seen in the patient and control groups with percentages of 73 and 40%, respectively. This difference was significant (P < 0.0001, OR: 3.9, CI 95% for OR: 2.6 to 5.9). No significant association was seen between the frequencies of the TGFB2 rs991967 polymorphism genotypes and clinical characteristics in POAG patients. CONCLUSION: The TGFB2 rs991967 polymorphism has a direct and significant association with POAG and significantly increases the risk of developing POAG.
ABSTRACT
INTRODUCTION: Multiple different procedures have been proposed to address complete sixth nerve palsy with severe abduction limitation. In this study, we report a modification of the Hummelsheim's procedure. It is in fact muscle pulley transposition that obviates the need for tenotomy or muscle splitting. For the first time, Muraki and Nishida proposed this technique. MATERIALS AND METHODS: Patients with large angle esotropia and abduction limitation of minus four or greater were enrolled. The surgery involved insertion of a polyester monofilament fiber suture through the temporal muscular margin of each vertical rectus muscle at approximately one-third of the width from the edge at 10 mm behind the muscle insertion. We tried to insert sutures away from the vessels of vertical muscles. Then, the vertical muscles were transposed without any tenotomy or splitting and the sutures were secured to the sclera 16 mm from the limbus in supratemporal and infratemporal quadrants. In all of the patients, this transposition was combined with medial rectus recession. RESULTS: A total of 10 patients were included; all of them had an esotropia with profound abduction deficit (-4 or more). The mean age of patients was 44.2 ± 9.2 years (mean ± standard deviation) (range: 28-57). The mean preoperative deviation was 49.5 ± 9 PD prism diopters (PD) (range: 40-65 PD). The mean preoperative abduction limitation was -4.8 ± 0.8. The patients were followed for at least 6 months. Postoperative deviation ranged from orthotropia to 12 PD of esotropia and all the patients obtained abduction at least beyond the midline. No vertical ductional disturbances or deviations were developed. The adduction was not compromised in any patient. Anterior segment ischemia did not occur in any patients. CONCLUSION: This procedure is comparable to traditional procedures with the advantages of no need to tenotomy or splitting and can be a good alternative to conventional Hummelsheim's procedure.
