Iris Thickness and Severity of Neovascular Glaucoma Determined Using Swept-Source Anterior-segment Optical Coherence Tomography

Clinical applications of anterior segment swept-source optical coherence tomography: A systematic review

Optical coherence tomography (OCT) is a non-invasive method that provides the opportunity to examine tissues by taking cross-sectional images. OCT is increasingly being used to evaluate anterior segment (AS) pathologies. Swept-source (SS) OCT allows greater penetration and achieves better visualization of the internal configuration of AS tissues due to the longer wavelength employed and high scan speeds. We reviewed the utilization of AS SS-OCT in various conditions including glaucoma, ocular surface pathologies, iris tumors, refractive surgery, cataract surgery, and scleral diseases. A systematic literature search was carried out on PubMed, Scopus, and Web of Science databases between January 1, 2008, and September 1, 2022 using the following keywords: AS SS-OCT; dry eye and SS-OCT; ocular surface and SS-OCT; cornea and SS-OCT; dystrophy and SS-OCT; glaucoma and SS-OCT; ocular surface tumors and SS-OCT; conjunctival tumors and SS-OCT; refractive surgery and SS-OCT; cataract and SS-OCT; biometry and SS-OCT; sclera and SS-OCT; iris and SS-OCT; ciliary body and SS-OCT; artificial intelligence and SS-OCT. A total of 221 studies were included in this review. Review of the existing literature shows that SS-OCT offers several advantages in the diagnosis of AS diseases. Exclusive features of SS-OCT including rapid scanning, deeper tissue penetration, and better image quality help improve our understanding of various AS pathologies.

Prognostic Evaluation of Vitrectomy Assisted by Lucentis in Diabetic Retinopathy and Neovascular Glaucoma

For verifying the prognosis of Lucentis-assisted vitrectomy (PPV) in diabetic retinopathy (DR) and neovascular glaucoma (NVG), a retrospective analysis of DR and NVG patients who were admitted to our hospital from July 2019 to December 2020 was conducted. According to the treatment protocol, subjects who had PPV intervention were in the control group (CG; n = 38) and those receiving Lucentis adjunctive PPV were included in the intervention group (RG; n = 40). The indicators between groups were listed: treatment success rate, postoperative complication rate, surgical outcome indicators, BCVA, intraocular pressure (IOP) change, foveal thickness, and VEGF level in aqueous humor. Indicators in RG were obviously higher than in CG, such as treatment success rate and surgical outcome indicators. Conversely, lower postoperative complication rate, postoperative BCVA, IOP, retinal fovea thickness, and VEGF level in aqueous humor were found in RG than in CG. Therefore, the study reached the following conclusions about vitrectomy assisted by Lucentis: (1) it effectively increases the success rate of treatment, decreases postoperative complications as well as surgical risks, and improves patients' vision; (2) it promotes the recovery of IOP, reduces macular edema and VEGF levels in aqueous humor, and inhibits the neonatal formation of blood vessels. It is finally confirmed that Lucentis adjuvant PPV in the treatment of DR complicated with NVG is safe and feasible.

Decreased iris thickness on swept-source optical coherence tomography in patients with primary open-angle glaucoma

PURPOSE

To investigate the iris thickness (IT) of patients with primary open-angle glaucoma (POAG) and older adults using anterior segment swept-source optical coherence tomography (SS-OCT).

METHODS

In this comparative cross-sectional study, 154 participants were enrolled, including 40 patients with POAG and 114 healthy individuals. Nasal-angle SS-OCT images were analysed using callipers to measure the thickness of the iris, including the anterior border layer, stromal, and pigmented epithelial layer, at 1 and 2 mm from the pupil edge. The relationship between IT and glaucoma severity was analysed, and receiver operating characteristic curves were constructed to assess the ability of each IT parameter to distinguish patients with glaucoma from healthy controls.

RESULTS

The IT parameters and iris area were lower in the POAG group than in the age-matched control group (p < 0.05). In the POAG group, the thickness of the pigmented epithelial layer at 1 and 2 mm was significantly correlated with the severity of glaucoma (p < 0.05). Iris area, with a cut-off of 1.43 mm² _, exhibited the highest sensitivity (85%) and specificity (64.81%; area under the curve = 0.783) for distinguishing patients with POAG from healthy controls. Older adults tended to have the thinnest IT, children had the smallest iris area (p < 0.05).

CONCLUSIONS

In patients with POAG, the severity of iris atrophy was associated with glaucoma severity. The results of IT measurements by SS-OCT may help in the clinical evaluation of POAG.

The disposable bandage soft contact lenses therapy and anterior segment optical coherence tomography for management of ocular graft-versus-host disease

PURPOSE

To identify the ocular surface changes of ocular graft-versus-host disease (GVHD) using anterior segment optical coherence tomography (AS-OCT) and examine the efficacy of disposable bandage soft contact lens (BSCL) treatment in ocular GVHD patients.

METHODS

This study is a prospective, Phase II clinical trial. Nineteen patients diagnosed with chronic GVHD based on the NIH criteria and ocular symptoms of NIH eye score 2 or greater were enrolled. Disposable BSCL was applied to the GVHD-affected eyes with topical antibiotic coverage. Ocular exams, eye symptom surveys, and AS-OCT were performed with signed informed consent. Patients were followed for one to three months.

RESULTS

Thirty-eight eyes of 19 patients with ocular GVHD underwent BSCL treatment in this study. AS-OCT scans were done in 14 out of 19 patients. The mean best-corrected visual acuity at enrollment, 2-week, and 4-week visits was 0.180, 0.128, and 0.163 logMAR, respectively. Twenty-four out of 25 eyes (96 %) that initially presented with conjunctival inflammation, twenty-three out of 30 eyes (76.7 %) that initially presented with punctate epithelial erosion, and 8 out of 15 (53.3 %) eyes that initially presented with filamentous keratopathy showed improvement after wearing BSCL for 2 to 4 weeks. AS-OCT revealed corneal epithelial irregularity, abnormal meibomian gland orifice, and conjunctival hyperemia, in patients with ocular GVHD.

CONCLUSIONS

BSCL treatment provided significant subjective and objective improvements in ocular GVHD patients. Meanwhile, we found that AS-OCT can be a promising diagnostic tool to characterize the ocular surface changes associated with ocular GVHD.

CHARGE Syndrome Associated with Angle Closure despite High Myopia: A Case Report with Structural Suggestion

CHARGE syndrome is associated with multiple malformations, and the main ocular abnormality is coloboma. We describe an unusual case of a 15-year-old girl with CHARGE syndrome having high intraocular pressure and narrow angle closure despite refractive high myopia (−9.0 dpt) in her left eye. Gonioscopy revealed peripheral anterior synechia (approximately 90°) in the superior quadrant of the left eye. Both eyes exhibited similar axial length (about 22 mm) and corneal curvature (about 8 mm). However, microcornea (9 mm), thicker central cornea and iris induced narrower anterior components in the left eye than in the right eye. Preventing the chance of acute primary angle closure attack, the patient underwent laser iridotomy in the left eye; however, long-term follow-up is needed. Additionally, we developed a hypothesis for the mechanism of unilateral angle closure despite high myopia by investigating the ocular structural parameters in detail.

Determination of iris thickness development in children using swept-source anterior-segment optical coherence tomography

Purpose

The uvea comprises the iris, ciliary body, and choroid. However, the development of the anterior part (iris and ciliary body) in children is not yet fully elucidated. We investigated the iris thickness (IT) in children using swept-source anterior-segment optical coherence tomography (ASOCT).

Methods

In this retrospective, clinic-based study, we enrolled 41 children (mean ± standard deviation: 6.8 ± 3.3 years; range: 3–16; 17 males) with normal or mild refractive error. Horizontal scanning images of swept-source ASOCT were analyzed in temporal and nasal angle areas. The ITs at 1 and 2 mm from the pupil edge were measured using swept-source ASOCT. The association between IT and age, sex, and ocular morphological parameters (i.e., axial length, average corneal curvature, central corneal thickness, inter-scleral spur distance, and anterior chamber depth) was assessed using Pearson’s correlation coefficient (r) and linear regression analysis.

Results

The average IT (temporal and nasal) at 1 and 2 mm were 0.432 ± 0.060 (0.302−0.569 mm) and 0.337 ± 0.045 (0.229−0.414 mm), respectively. There was a significant correlation between age and average IT (r = 0.45, P = 0.002 at 1 mm and r = 0.31, P = 0.042 at 2 mm). Multiple linear regression analysis revealed that age (coefficient: 0.01), axial length (−0.02), average corneal curvature (0.01), and anterior chamber depth (0.01) at 1 mm as well as age (0.00), average corneal curvature (0.09), anterior chamber depth (0.06), and male (–0.02) at 2 mm were identified as predictors of IT.

Conclusions

IT in children increases with age. Additionally, IT was thinner with longer axial length and in males, thicker in eyes with deeper anterior chamber and flatter corneal curvature. Our study may partly explain the development of eyeball structures in children.