Ophthalmic Surgery Lasers & Imaging最新文献

Background and objective: To examine the exact position of implanted Keraring (Mediphacos, Belo Horizonte, Brazil) segments by high-resolution anterior segment optical coherence tomography (AS-OCT).

Patients and methods: This study included 17 eyes of 13 patients with keratoconus who underwent uneventful intracorneal ring segment implantation with the aid of femtosecond laser. Eyes were evaluated by AS-OCT at the third postoperative month. Distance from the apex of the triangular cross-section of the ring segment to the anterior corneal surface and distances from two basal corners to the posterior corneal surface were measured.

Results: Distance from apex to anterior corneal surface (263.1 ± 42.9 μm) was significantly smaller than target depth calculated intraoperatively (356.9 ± 35.7 μm, P < .001). Distance between outer basal corner and posterior corneal surface was significantly greater than distance between inner basal corner and posterior corneal surface.

Conclusion: High-resolution AS-OCT is a rapid, convenient, and valuable technique in the follow-up of patients with implanted Keraring segments that may be helpful in predicting ring-related complications.

The authors demonstrate the feasibility and advantage of spectral-domain optical coherence tomography (SD-OCT) for single-shot ocular biometric measurement during the development of the mouse eye. A high-resolution SD-OCT system was built for single-shot imaging of the whole mouse eye in vivo. The axial resolution and imaging depth of the system are 4.5 μm (in tissue) and 5.2 mm, respectively. The system is capable of acquiring a cross-sectional OCT image consisting of 2,048 depth scans in 85 ms. The imaging capability of the SD-OCT system was validated by imaging the normal ocular growth and experimental myopia model using C57BL/6J mice. The biometric dimensions of the mouse eye can be calculated directly from one snapshot of the SD-OCT image. The biometric parameters of the mouse eye including axial length, corneal thickness, anterior chamber depth, lens thickness, vitreous chamber depth, and retinal thickness were successfully measured by the SD-OCT. In the normal ocular growth group, the axial length increased significantly from 28 to 82 days of age (P < .001). The lens thickness increased and the vitreous chamber depth decreased significantly during this period (P < .001 and P = .001, respectively). In the experimental myopia group, there were significant increases in vitreous chamber depth and axial length in comparison to the control eyes (P = .040 and P < .001, respectively). SD-OCT is capable of providing single-shot direct, fast, and high-resolution measurements of the dimensions of young and adult mouse eyes. As a result, SD-OCT is a potentially powerful tool that can be easily applied to research in eye development and myopia using small animal models.

Background and objective: To evaluate wound morphology and integrity using contrast-enhanced spectral-domain optical coherence tomography (SD-OCT).

Patients and methods: Eighteen patients (18 eyes) undergoing unilateral routine cataract surgery were enrolled. SD-OCT imaging of the corneal wound was performed immediately following cataract surgery and on postoperative day 1. A topical contrast agent, prednisolone acetate 1%, was used to help evaluate wound integrity. OCT features of the corneal incision and changes in wound interface reflectivity after administration of topical prednisolone acetate 1% were analyzed. Main outcome measures were quantitative and qualitative description of wound morphology and contrast enhancement of the wound interface.

Results: Internal wound gape was found in 89% of eyes. Gape area decreased by 43% from days 0 to 1 (462 vs 273 μm(2); P < .01). Contrast enhancement at the wound interface was seen in 56% of eyes on day 0 compared to 17% on day 1 following application of prednisolone acetate 1% (P < .05). Decreased intraocular pressure correlated with increased contrast enhancement (P < .05).

Conclusion: Wound morphology evolves during the early postoperative period. Wound gape and ingress of a topical contrast agent decrease during the first 24 hours following surgery. Contrast enhancement at the wound interface increases as the intraocular pressure decreases.

Background and objective: To investigate near infrared iris transillumination (NIRit) imaging as a new method to quantify pupil shape, size, and position because the imaging modality can uniquely provide simultaneous information regarding iris structural details that influence pupil characteristics and because exploration of related techniques could promote discovery helpful to clinical research and care.

Patients and methods: Digital NIRit images of normal and diseased eyes were used along with computer-assisted techniques to quantify four primary pupil parameters, including pupil roundness (PR), pupil ovalness (PO), pupil size (PS), and pupil eccentricity (PE). A combined measure of PR and PO was also developed (the pupil circularity index [PCI]). Repeatability of the measures was studied and example analyses were performed.

Results: Pupil measures could be calculated for right eyes of 307 subjects (164 normal, 143 other), with fewer than 0.5% exclusions due to image quality. Repeatability study did not show significant bias (P < .05) for any of the four primary measures. Example analyses could show age-associated differences in pupil shape (≥ 50 year olds had less regular pupils than < 50 year olds: median PCI = 0.009 vs 0.006; P < .01) and that a group of pigment dispersion syndrome subjects (n = 27) had less regular pupils than a group of matched controls (PO = 0.9966 vs 0.9990; P < .05).

Conclusion: Digital NIRit imaging can provide novel, reliable, and informative methods to quantify pupil characteristics while providing simultaneous information about iris structure that may influence these parameters.

The authors report four cases of vitreomacular traction syndrome with splitting of the posterior vitreous cortex. Spectral-domain optical coherence tomography (SD-OCT) was performed consecutively in 35 patients with vitreomacular traction syndrome between June 2007 and February 2011. SD-OCT showed perifoveal posterior vitreous detachment with splitting of the posterior vitreous cortex in 4 of 35 eyes (at the fovea in 1 eye and the perifovea in 3 eyes). The separated cortex of the posterior lamella adhered to the retina in all 4 eyes. The posterior vitreous cortex may split at the macular area in cases of vitreomacular traction syndrome.

The different therapeutic responses observed among choroidal neovascularization (CNV) of different etiologies, ages, and locations might be related to the presence of varied mediators. Two surgically removed peripapillary CNVs from two different patients were analyzed. One of the patients had received one intravitreous injection of bevacizumab 3 months earlier. CNV was analyzed using conventional histology and immunohistochemistry. Histological analysis showed intense neovascularization and epithelial and glial components. Vascular endothelial growth factor (VEGF) receptors were found in the endothelial cells and the epithelial cells of the CNV. VEGF was expressed in the patient who had not been previously treated with anti-VEGF. The CNV was deeply infiltrated by glial cells and invaded by microglial cells in one case. VEGF and VEGF receptors may be expressed, suggesting that therapies aiming at VEGF may be efficient only for a subtype of CNV and at a certain time point of their evolution.

A diagnosis of choroidal metastasis is based on the patient's clinical history, the tumor's ophthalmoscopic appearance, and instrumental imaging results such as ultrasonography, fluorescein angiography, fundus autofluorescence, indocyanine green angiography, and optical coherence tomography. Spectral-domain optical coherence tomography (SD-OCT) has provided additional useful information for clinical diagnosis: a pattern of hyperintense irregular spots in the context of the photoreceptor layer and in the retinal pigment epithelium, subretinal fluid, and marked irregularity of the retinal pigment epithelium with thickening and gross undulation. The authors describe a case of bilateral choroidal metastasis presenting peculiar SD-OCT features acquired at different stages. They emphasize the central role of SD-OCT among instrumental imaging procedures and for final successful diagnosis.

The authors demonstrate a reproducible technique using processed pericardium to seal sclerostomy track during glaucoma shunt revision. The suggested method involves placement of a wedge-shaped processed pericardial graft into the old sclerostomy tract following tube explantation. The graft is trimmed and sutured to the sclera. The tube is reinserted into a new sclerostomy and then sutured in place and covered in the usual fashion. This method allowed relatively easy treatment of three patients with patulous sclerostomy with necrotic edges. A successful tube revision and repositioning of the tube using this technique was performed on three patients with exposed tubes. The intraocular pressure was between 8 and 12 mm Hg from postoperative day 1. The authors suggest the use of pericardium plug to adequately seal the old sclerostomy track during glaucoma shunt revision. The plug allows tube repositioning at a new site without the need to suture the friable sclerostomy edges.

This report describes a case of cancer-associated nummular retinal pigment epithelium loss associated with uterine cancer. The patient had progressive visual loss despite treatment with plasmapheresis, intravenous immunoglobulin, and local injection of corticosteroids. Clinical deterioration was corroborated by extension of the areas of retinal pigment epithelium loss, progression of cataracts, and growth of pigmented choroidal and iris lesions. Previously published cases of cancer-associated nummular retinal pigment epithelium loss did not describe the presence of cataracts or uveal melanocytic lesions. This case expands the clinical spectrum of bilateral diffuse uveal melanocytic proliferation.