Deepa Anijeet

Imaging and Evaluation of Corneal Vascularization Using Fluorescein and Indocyanine Green Angiography

PURPOSE To evaluate indocyanine green angiography (ICGA) and fluorescein angiography (FA) in imaging and quantifying corneal neovascularization (CNV). METHODS Patients with CNV were studied using a standardized protocol of color digital photography, FA, and ICGA. Images were graded independently by two observers and assessed for quality, phases of fluorescence, and leakage. Areas of CNV and vasculature geometric properties were analyzed and quantified by an automated program. RESULTS Twenty-three patients with good quality images were included. Mean times to appearance of ICG and fluorescein were 17 and 20 seconds (P = 0.10). Best images for analysis were obtained at 64 seconds for ICGA and 47 seconds for FA. CNV not apparent on color or FA, particularly in the presence of scarring, was well delineated by ICGA. Leakage of ICGA did not occur. Fluorescein leakage from apical CNV images occurred significantly earlier (32 seconds) in patients with CNV of <6-month duration than those of >1-year (50 seconds) duration (P = 0.04). Mean area of CNV and vessel diameter were similar with ICGA (8.79 mm(2), 0.058 mm) or FA (7.74 mm(2), 0.054 mm) but significantly larger than on color (1.94 mm(2), 0.026 mm) images (P < 0.01). Vessel tortuosity was similar on ICGA (1.16), FA (1.17), and color (1.15) (P = 0.27). CONCLUSIONS Combined use of FA and ICGA are valuable tools with which to assess CNV and provide better vessel delineation than can be obtained with only color images. Parameters used to assess CNV, such as leakage, area, diameter, and tortuosity, may be useful measures for evaluating treatment. Videography is useful for detecting early leakage.

Quantifying changes in corneal neovascularization using fluorescein and indocyanine green angiography

PURPOSE To quantify changes in corneal neovascularization in patients with active keratitis after treatment using color imaging, fluorescein angiography (FA), and indocyanine green angiography (ICGA). DESIGN Prospective, interventional case series. METHODS Twelve consecutive patients were studied. A comparison of corneal neovascularization parameters was undertaken before and after resolution of the keratitis. A slit-lamp digital camera acquired images of the neovascularization using color imaging, FA, and ICGA. The best-quality images were selected using a grading system, and the neovascular regions of interest were analyzed using automated in-house software. The parameters of analysis were vessel area, diameter, tortuosity, and FA dye leakage. RESULTS There was a significant reduction in the area of neovascularization after treatment on color imaging (0.78 mm(2); P < .05), FA (2.33 mm(2); P < .01), and ICGA (2.07 mm(2); P < .01). There was also a significant reduction in mean vessel diameter across the region of interest for each patient, more marked on FA (42.74 to 32.52 μm; P < .01) and ICGA (44.77 to 33.29 μm; P < .01) than on color imaging (29.10 to 25.17 μm; P < .01). A significant change in vessel tortuosity was not observed. There was a significant increase in FA dye leakage time (12.41 seconds; P < .05) after treatment. CONCLUSIONS We demonstrate application of an objective method for analyzing changes in corneal neovascularization. The excellent vessel delineation with ICGA even in the presence of stromal scars makes it an ideal agent for measurement of vessel parameters. FA is useful at detecting vessel leakage, and the time to leakage provides a possible measure of vessel staging.

Femtosecond laser‐assisted lamellar keratectomy for corneal opacities due to macular dystrophy: an interventional case report

Superficial corneal opacities can have a significant effect on visual acuity, especially if they are along the visual axis. In these cases, surgical interventions must be considered, such as anterior lamellar keratoplasty and phototherapeutic keratectomy (PTK). These techniques have been associated with irregular resection, keratectasia and astigmatism, which can lead to disabling visual effects. We describe a case in which planned lamellar keratectomy using the femtosecond laser (FSL) deferred more invasive surgery and provided significant visual improvement and aided histological diagnosis in a patient with poor vision secondary to bilateral corneal opacities of unknown aetiology. A 63-year-old man was referred with blurred vision and glare in both eyes. He had a long-standing history of bilateral corneal opacities of unknown aetiology and a history of laryngeal cancer. Best spectacle-corrected visual acuity (BSCVA) was LogMAR 0.78 OD and 0.60 OS. Subjective refraction was +2.25/+9.00 × 143 OD and +0.50/ +6.00 × 160 OS. Slit lamp biomicroscopic examination revealed multiple, bilateral gray-white stromal opacities, principally located in the anterior stroma, throughout the cornea (Fig. 1). The surgical option of an anterior lamellar keratoplasty was offered but was declined, and the patient instead opted for a therapeutic FSL lamellar keratectomy. The right eye was treated first, followed by the left. The preand postoperative keratometric values as measured by corneal topography (Orbscan IIz instrument, Bausch & Lomb, Germany) are shown in Table 1. A free corneal flap of diameter of 9.5 mm and 110 μm in thickness was created for each eye using the FSL (Ziemer FEMTO LDV, Ziemer, Germany) with a bed energy of 900 mW. The excised flap was then sent for histology. There were no perioperative or postoperative complications. Histology of the excised flap of tissue confirmed the diagnosis of macular dystrophy. At 24 months BSCVA was logMAR 0.17 in both eyes. Subjective refraction was +0.50/+4.25 × 123 OD and −1.50/+3.00 × 160 OS. Slit lamp biomicroscopic examination showed residual but much reduced corneal haze, not affecting the visual axis (Fig. 1). The refractive surgical effect showed a change in the refractive error (myopic shift and reduction in astigmatism) of −1.14/−6.23 × 154 OD and −2.00/−3.00 × 160 OS, as shown in Table 1. The goal of treatment of anterior stromal opacities of the cornea is to ablate the opacities in the visual axis and remove the least amount of tissue possible to achieve the optimal visual outcome. Treatment options include anterior lamellar keratectomy using a microkeratome with or without PTK, as well as PTK with or without Mitomycin C, which have been associated with irregular resection,

Evaluation of Corneal Vessels

corneal new vessels can result in significant loss of vision as well as reduce graft survival. Recently, newer treatment modalities have been introduced. however, attempts to meet the challenge of evaluating corneal vessels by quantification are evolving. In vivo evaluations range from computer-aided analysis of colour images to determination of area, diameter and tortuousity of blood vessels on indocyanine green angiography images. attempts at developing a fully automated process of evaluation and quantification are hampered by the anatomical variations of limbus, random nature of blood vessels and multiple levels of involvement of the corneal stroma. currently, semi-automated methods require manually fixing the limbus prior to quantification of vessels. using indocyanine green angiography, the full extent of corneal vessels even in the presence of scarring can be determined. With the evolution of new techniques, it is hoped that a robust corneal vessel quantifying tool will be described in the near future that will aid the effectiveness of treatment strategies.