Generation of Anterior Segment of the Eye Cells from hiPSCs in Microfluidic Platforms

Ophthalmic diseases affect many people, causing partial or total loss of vision and a reduced quality of life. The anterior segment of the eye accounts for nearly half of all visual impairment that can lead to blindness. Therefore, there is a growing demand for ocular research and regenerative medicine that specifically targets the anterior segment to improve vision quality. This study aims to generate a microfluidic platform for investigating the formation of the anterior segment of the eye derived from human induced pluripotent stem cells (hiPSC) under various spatial-mechanoresponsive conditions. Microfluidic platforms are developed to examine the effects of dynamic conditions on the generation of hiPSCs-derived ocular organoids. The differentiation protocol is validated, and mechanoresponsive genes are identified through transcriptomic analysis. Several culture strategies is implemented for the anterior segment of eye cells in a microfluidic chip. hiPSC-derived cells showed anterior eye cell characteristics in mRNA and protein expression levels under dynamic culture conditions. The expression levels of yes-associated protein and transcriptional coactivator PDZ binding motif (YAP/TAZ) and PIEZO1, varied depending on the differentiation and growth conditions of the cells, as well as the metabolomic profiles under dynamic culture conditions.

Optical Coherence Tomography Angiography Imaging of Foveal Atrophy Secondary to Commotio Retinae in a Pediatric Patient

Optical coherence tomography-angiography (OCTA) is a fast, reliable, and non-invasive technique for the diagnosis and follow-up of patients with commotio retinae (CR). Severity of the damage to the retinal and choroidal microvasculature in OCTA imaging and the visual prognosis are directly related to the severity of trauma. There are a few published reports on OCTA in CR that shows alterations of the retinal or superficial choroidal vessels and choriocapillary plexus. OCTA imaging seems to be predictive for visual prognosis. Herein, we present a 6-year-old boy, who had blunt trauma to the right eye with a stick during outdoor playing with visual acuity reduction to 0.1 following resolution of the Berlin's edema. In our case, OCTA revealed damage to the outer layers of the retinae and choriocapillaris and resulting in permanent vision loss. OCTA is a non-invasive, rapid, and safe imaging technique that qualitatively and quantitatively analyzes blood flow from the superficial capillary plexus to the choriocapillaris, which can be predictive in the visual prognosis.

Development of lacrimal gland organoids from iPSC derived multizonal ocular cells

Lacrimal gland plays a vital role in maintaining the health and function of the ocular surface. Dysfunction of the gland leads to disruption of ocular surface homeostasis and can lead to severe outcomes. Approaches evolving through regenerative medicine have recently gained importance to restore the function of the gland. Using human induced pluripotent stem cells (iPSCs), we generated functional in vitro lacrimal gland organoids by adopting the multi zonal ocular differentiation approach. We differentiated human iPSCs and confirmed commitment to neuro ectodermal lineage. Then we identified emergence of mesenchymal and epithelial lacrimal gland progenitor cells by the third week of differentiation. Differentiated progenitors underwent branching morphogenesis in the following weeks, typical of lacrimal gland development. We were able to confirm the presence of lacrimal gland specific acinar, ductal, and myoepithelial cells and structures during weeks 4-7. Further on, we demonstrated the role of miR-205 in regulation of the lacrimal gland organoid development by monitoring miR-205 and FGF10 mRNA levels throughout the differentiation process. In addition, we assessed the functionality of the organoids using the β-Hexosaminidase assay, confirming the secretory function of lacrimal organoids. Finally, metabolomics analysis revealed a shift from amino acid metabolism to lipid metabolism in differentiated organoids. These functional, tear proteins secreting human lacrimal gland organoids harbor a great potential for the improvement of existing treatment options of lacrimal gland dysfunction and can serve as a platform to study human lacrimal gland development and morphogenesis.

Orbital Apex Syndrome Secondary to Herpes Zoster Ophthalmicus

Orbital apex syndrome is a rare complication of herpes zoster ophthalmicus. A patient being followed in our clinic for herpes zoster ophthalmicus developed orbital apex syndrome in the second week of treatment. Clinical diagnosis was supported by magnetic resonance imaging. Treatment with systemic steroid and antiviral therapy resulted in total regression of ophthalmoplegia at 2 months. However, optic neuropathy-induced vision loss was permanent. This case report examines orbital apex syndrome secondary to herpes zoster ophthalmicus, which has rarely been documented in the ophthalmic literature.

Autofluorescence imaging of pingueculae

AIMS

To analyse the autofluoresence (AF) properties of pingueculae and compare the size of AF with the extent of the visible lesion.

METHODS

Forty eyes of 23 patients with pingueculae were included in the study. AF images were obtained using an HRA2 confocal scanning laser ophthalmoscope; anterior segment photographies were obtained using TRC-50IX, IMAGEnet 2000 Digital Imaging System. The AF characteristics of pingueculae were analysed. The extent of visible lesion in anterior segment photography and AF image was compared.

RESULTS

AF images revealed well-defined hyper-autofluorescence in the area of pinguecula, which was greater than the extent of visible pinguecula in the slit-lamp examination, in 40 of 56 lesions (71.4%). In none of the eyes was the hyperautofluorescent area smaller than the extent of visible lesion.

CONCLUSION

Pingueculae display hyperautofluorescence in AF imaging. The real size of pingueculae may be estimated by its AF characteristics, which is mostly larger than the visible lesion.

Optical coherence tomography evaluation of macular edema after intravitreal triamcinolone acetonide in patients with parafoveal telangiectasis

PURPOSE

Parafoveal telangiectasis (PT) is a developmental or acquired microvascular abnormality of the macula. Leakage of the abnormal parafoveal capillaries leads to macular edema with subsequent decrease in visual acuity. Intravitreal triamcinolone acetonide is recently widely used in the management of intraocular proliferative, edematous, and neovascular diseases.

METHODS

This report presents the evaluation of three cases with PT in whom intravitreal triamcinolone acetonide (IVTA) injection was performed. Fundus fluorescein angiography (FA) and optical coherence tomography (OCT) were used in follow-up of the patients.

RESULTS

Following pars plana intravitreal injection of 4 mg of triamcinolone acetonide, the patients had angiographic improvement of the macular edema and minimal decrease in retinal thickness on OCT, accompanied by improvement in visual acuity and subjective visual assessment.

CONCLUSIONS

The results of the present study on parafoveal capillary telangiectasis suggest that the intravitreal injection of triamcinolone acetonide may be a therapeutic option to increase visual acuity and decrease vascular leakage on FA. Following IVTA procedure, follow-up of these patients with both OCT and FA is important for correct clinical evaluation. Future studies on this method seem to be warranted.

Radial keratotomy for the optical rehabilitation of mild to moderate keratoconus: more than 5 years' experience

PURPOSE

To present the authors' long-term experience of radial keratotomy (RK) for the optical rehabilitation of patients with mild to moderate keratoconus--central corneal thickness of greater than 400 microm and without apical scarring.

METHODS

In this observational, noncomparative series of cases, all consecutive patients with mild or moderate keratoconus, treated by RK between 1990 and 2002, with at least 1 year follow-up were included. A total of 170 eyes of 96 patients were investigated. Mean follow-up was 42.08 +/- 28.14 months. Visual acuity, refraction, corneal curvature, central corneal thickness, and complications were evaluated.

RESULTS

In all of the control visits, mean uncorrected and best spectacle corrected visual acuities were better than preoperative values (p<0.0001). Preoperative myopic spherical refraction decreased significantly (p<0.0001), and remained relatively unchanged throughout the follow-up (p=0.43). A small but statistically significant decrease from baseline was ob-served in astigmatism (p=0.038), which almost disappeared 1 year after the surgery (p=0.47). The surgery produced a statistically significant flattening of the corneal curvature (p<0.0001). Central corneal thickness did not change significantly (p>0.05) in either control visit. In 33 eyes (19.4%), re-deepening of the incisions was required. In 3 eyes (1.8%) penetrating keratoplasty was performed, due to disease progression in 2 eyes (1.2%) and acute traumatic hydrops in 1 eye (0.6%). In 4 eyes (2.2%) microperforation, in 2 eyes (1.2%) macroperforation, in 1 eye (0.6%) infectious keratitis, and in 1 eye (0.6%) hyperopic shift occurred.

CONCLUSIONS

RK surgery was found to be a reasonable option for the rehabilitation of a selected group of keratoconus patients in the early or moderate stages.