Clinical Applications of Anterior Segment Optical Coherence Tomography: An Updated Review.

Since its introduction, optical coherence tomography (OCT) has revolutionized the field of ophthalmology and has now become an indispensable, noninvasive tool in daily practice. Most ophthalmologists are familiar with its use in the assessment and monitoring of retinal and optic nerve diseases. However, it also has important applications in the assessment of anterior segment structures, including the cornea, conjunctiva, sclera, anterior chamber, and iris, and has the potential to transform the clinical examination of these structures. In this review, we aim to provide a comprehensive overview of the potential clinical utility of anterior segment OCT (AS-OCT) for a wide range of anterior segment pathologies, such as conjunctival neoplasia, pterygium, scleritis, keratoconus, corneal dystrophies, and infectious/noninfectious keratitis. In addition, the clinical applications of AS-OCT (including epithelial mapping) in preoperative planning and postoperative monitoring for corneal and refractive surgeries are discussed.

Retinal capillary plexus in Parkinson's disease using optical coherence tomography angiography.

AIM: To evaluate the alterations of the retinal microvasculature and foveal avascular zone in patients with Parkinson's disease (PD) using optical coherence tomography angiography (OCT-A). METHODS: A retrospective study of PD patients examined in the Ophthalmology Department of the General Hospital of Athens, "Georgios Gennimatas" from March 2021 to March 2022 was conducted. Totally 44 patients with PD were included and 18 healthy controls were examined, hence a total of 124 eyes were enrolled in the study. The foveal and parafoveal superficial and deep capillary plexus vascular density (fSCP-VD, fDCP-VD, pSCP-VD, pDCP-CD) and foveal avascular zone (FAZ) were quantified with OCTA. Optical coherence tomography (OCT) was used to measure macular thickness. Our statistical analysis was conducted by using a mixed effect linear regression model. RESULTS: After adjustment for age and gender, the mean parafoveal superficial capillary plexus vascular density (pSCP-VD) and mean parafoveal deep capillary plexus vascular density (pDCP-VD) were significantly decreased in individuals with PD (P<0.001 in both) by -2.35 (95%CI -3.3, -1.45) and -7.5 (95%CI -10.4, -4.6) respectively. fSCP-VD and fDCP-VD didn't approach statistical significance. The FAZ area and perimeter were significantly decreased (P<0.001 in both) by -0.1 mm2 (95%CI -0.13, -0.07) and -0.49 mm2 (95%CI -0.66, -0.32) respectively. Circularity didn't approach statistical significance. Central retinal thickness (CRT) was significantly decreased in individuals with PD (P<0.001) by -23.1 µm (95%CI -30.2, -16) and temporal retinal thickness (TRT) was decreased (P=0.025) by -11 µm (95%CI -22, -1.5) while nasal retinal thickness (NRT) only approached statistical significance (P=0.066). CONCLUSION: The mean pSCP-VD, pDCP-VD, CRT and TRT are significantly decreased and FAZ is altered in individuals with PD. These findings can be potentially used as biomarkers for the diagnosis and evaluation of early PD.

The TsiogkaSpaeth grid for detection of neurological visual field defects: a validation study.

BACKGROUND: The TsiogkaSpaeth (TS) grid is a new, low-cost, and easy to access portable test for visual field (VF) screening which could be used by clinicians in everyday clinical practice. Our study aimed to determine the validity of an innovative screening grid test for identifying neurological disease-associated VF defects. METHODS: We enrolled two groups of participants: We assessed the one eye of ten consecutive adult patients with different types of neurological disease associated VF defects and ten eyes of controls in each group. The TS grid test was performed in each group. Sensitivity, specificity, and positive and negative predictive values of the TS grid scotoma area were assessed using the 24-2 VF Humphrey field analyzer (HFA) as the reference standard. RESULTS: Sensitivity and specificity of the TS grid test were 100% and 90.91%, respectively. The area under curve was 0.9545 with 95% CI 0.87-1.00. There was a significant correlation between the number of missed locations on the TS grid test and the visual field index of the HFA 24-2 (r = 0.9436, P < .0001). CONCLUSION: The sensitivity and specificity of the TS grid test were high in detecting VF defects in neurological disease. The TS grid test appears to be a reliable, low-cost, and easily accessed alternative to traditional VF tests in diagnosing typical neurological patterns of visual field defects. It would be useful in screening subjects for neurologically derived ocular morbidity in everyday clinical practice and in remote areas deprived of specialized health care services.

A 30-Year-Old Man with a Recent History of COVID-19 Requiring Treatment with Corticosteroids Who Developed Bilateral Central Serous Chorioretinopathy During 7-Month Follow-Up.

BACKGROUND Central serous chorioretinopathy (CSCR) involves a localized serous macular detachment, secondary to retinal pigment epithelial and choroidal vascular changes, which can be an adverse effect of corticosteroid use. Most CSCR cases resolve spontaneously, and normal vision returns, while some chronic cases can result in blindness. This report is of a 30-year-old man with a recent history of Corona virus disease (COVID)-19 requiring corticosteroid treatment who developed bilateral CSCR with unilateral fibrin and a 7-month follow-up. CASE REPORT A 30-year-old male patient presented with malaise and high fever. The patient tested positive for COVID-19, caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) virus and was admitted. During hospitalization, he received intravenous (IV) corticosteroids for 1 week (6 mg dexamethasone IV once daily). Following hospitalization, the patient received per os methylprednisolone 16 mg (16 mg once daily for 3 days, 8 mg once daily for 3 days, 4 mg once daily for 3 days, and 2 mg once daily for 3 days). One month later, the patient presented with bilateral visual acuity (VA) deterioration and acute CSCR. The diagnosis and follow-up were performed by optical coherence tomography (OCT) and fundus fluorescein angiography (FFA). The patient was followed-up for a period of 7 months, during which, although the VA improved and remained stable, the OCT findings were changing. CONCLUSIONS This report highlights the importance of timely ophthalmological examination in patients with sudden vision loss and identification of the association between corticosteroid use and CSCR, as well as the importance of a longer follow-up period.

Outcomes of Combined Penetrating Keratoplasty and Limbal Stem Cell Transplantation: A Meta-Analysis on Simultaneous Versus Sequential Surgery.

PURPOSE: The objective of this study is to perform a systematic review and meta-analysis of the published studies on limbal stem cell transplantation (LSCT) combined with penetrating keratoplasty (PK) performed either simultaneously or sequentially. METHODS: An extensive search was conducted in the MEDLINE and Google Scholar databases. Prospective and retrospective trials and case series reporting on the outcomes of LSCT with PK were included. Primary outcomes were the stability of the ocular surface and the rejection and/or failure of the corneal graft. RESULTS: A total of 209 eyes from 13 studies were included in the simultaneous group and 489 eyes from 33 studies in the sequential group. Ocular surface stability was 88% [95% confidence interval (CI), 79%-96%] for sequential cases and 64% (95% CI, 43%-82%) for simultaneous cases ( P = 0.001). The graft failure rate was 15% (95% CI, 6%-26%) for sequential cases and 44% (95% CI, 31%-58%) for simultaneous cases ( P < 0.001). For cases performed sequentially, subgroup analysis revealed a stable ocular surface in 97% (95% CI, 91%-100%) of autograft cases and 63% (95% CI, 45%-80%) of allograft cases ( P < 0.001). The graft failure rate in sequential cases was 7% (95% CI, 0%-18%) for autografts and 34% (95% CI, 18%-52%) for allografts ( P < 0.001). CONCLUSIONS: Sequential LSCT followed by PK demonstrated superior results in terms of ocular surface stability and graft retention compared with simultaneous LSCT and PK. Limbal stem cells of autologous origin fare better than allogeneic ones in sequential cases.

Paramacular Acute Middle Maculopathy Associated with Glyceryl Trinitrate.

An unusual case of nitroglycerin-induced Paracentral Acute Middle Maculopathy (PAMM) is presented. A 50-year-old patient with sudden vision loss and scotoma was followed up with swept-source optical coherence tomography (SS-OCT), optical coherence tomography-angiography (OCT-A), and fluorescein angiography (FA). An anal fissure treated with glyceryl trinitrate (GTN) 0.2% ointment with headache and dizziness after application was reported. Fundoscopy OS revealed mild retinal venous dilatation and tortuosity with scattered blot hemorrhages and subtle, parafoveal, whitish lesions in the outer retina. SS-OCT revealed diffuse, hyperreflective lesions in the inner plexiform (IPL), inner nuclear (INL), and outer plexiform layers (OPL). OCT-A revealed focal dropout in the deep capillary plexus. FA showed masking due to blot hemorrhages and early punctuate leakage in the inner retina. This entity was identified as nitroglycerin-induced PAMM. Over the following 8 months, after discontinuation of the ointment application, the patient was symptom-free with stable visual acuity. OCT revealed INL/OPL thinning and confirmed complete lesion resolution. This first report of retinal vascular abnormalities due to nitrite ointment provides an insight into an unknown side effect of nitroglycerin ointment use. A dose-dependent correlation between GTN application and retinal vascular abnormalities remains to be confirmed.

Epiretinal membrane-induced intraretinal neovascularization.

PURPOSE: To report a 71-year-old male patient diagnosed with epiretinal membrane-induced intraretinal neovascularization. OBSERVATIONS: The presence of an epiretinal membrane (ERM) was confirmed by Optical Coherence Tomography (OCT), fluorescein and indocyanine angiography. Optical coherence tomography angiography (OCT-A) revealed a neovascular membrane within the ERM. Intravitreal ranibizumab injections were administered three times at four-week intervals. Imaging revealed a stable membrane with no leakage. Five months after the third injection, OCT revealed intraretinal fluid. OCT-A showed a new branch of the neo-vascular membrane at the superficial capillary plexus. Following an additional ranibizumab injection, the membrane stabilized. CONCLUSIONS AND IMPORTANCE: It is conceivable that neovascularization developed due to, or in close conjunction with an epiretinal membranes already in place.

Secondary DMEK following failed primary DMEK.

PURPOSE: To report the outcomes of secondary Descemet Membrane Endothelial Keratoplasty (DMEK) performed for failed primary DMEK. METHODS: The medical records of all patients undergoing secondary DMEK due to failure of primary DMEK were reviewed. Reasons for failure were sought and best-corrected visual acuity (BCVA), endothelial cell density (ECD) and complications of secondary DMEK were evaluated. RESULTS: A total of 10 cases undergoing secondary DMEK following failed primary DMEK were identified. Presumed reasons for failure included donor ECD ≤ 2300 cells/mm2 (n = 4), difficulty during graft preparation (n = 2), graft detachment (n = 2), acute angle closure due to retroiridal air dislocation (n = 1), inverse graft positioning (n = 1) and phacoemulsification (n = 1). Eyes with low visual potential were not excluded from the study group. We should note that one patient (case no7) had both low ECD and graft detachment as reasons for failure and as a result he is counted twice. Median BCVA (decimal fraction) increased from 0.1 (range, 0.01; 0.3) to 0.5 (0.05; 1.0) at one month and remained stable thereafter. A BCVA of 0.5 or higher was achieved in 7 cases at the final follow-up. Mean ECD fell from 2628 ± 284 cells/mm2 to 1391 ± 252cells/mm2 at 6 months (47% reduction) and 959 ± 225cells/mm2 at 24 months (64% reduction) (P ≤ 0.028). Complications included the incomplete removal of the primary graft and mild iris bleeding, decompensation of a preexisting primary open-angle glaucoma and retroiridal air dislocation. CONCLUSIONS: Apart from low donor ECD, surgical challenges, i.e., difficulty with graft preparation, inverse graft positioning, and retroiridal air dislocation, were main reasons for failure of primary DMEK. Secondary DMEK showed a good safety profile and reasonable visual outcomes.

Treatment of Progressive Scleromalacia Perforans by Tectonic Enhancement With Lyophilized Equine Pericardium.

PURPOSE: To describe the off-label use of lyophilized equine pericardium for tectonic enhancement of the sclera in a case of progressive scleromalacia perforans. METHODS: An 82-year-old woman with a history of varicella zoster virus sclerokeratitis presented with a progressively expanding scleral thinning at the superonasal quadrant of the anterior sclera of her left eye. The eye was blind because of intractable glaucoma. To avoid perforation of the exposed choroid, a single layer of lyophilized equine pericardium was sutured over the scleral perforation. After performing a conjunctival peritomy in the involved superonasal area, the pericardium was trimmed, fixated on the anterior sclera with 4 Nylon 9 to 0 interrupted sutures, and tucked underneath the conjunctival pocket. The conjunctiva was adapted with 6 Vicryl 8 to 0 interrupted sutures. RESULTS: The postoperative course was uneventful. At 12 months after surgery, slit-lamp biomicroscopy showed a stable subconjunctival sheet covering the staphyloma, whereas anterior segment optical coherence tomography demonstrated thickening of the ocular wall, suggesting successful integration of the pericardium. CONCLUSIONS: Suturing of equine pericardium over a scleral defect was feasible allowing successful reinforcement of the staphyloma in a case of severe scleromalacia perforans.