A journey through the world of vitreous.

Vitreous, one of the largest components of the human eye, mostly contains water. Despite decades of studying the vitreous structure, numerous unanswered questions still remain, fueling ongoing active research. We attempt to provide a comprehensive overview of the current understanding of the development, morphology, biochemical composition, and function of the vitreous. We emphasize the impact of the vitreous structure and composition on the distribution of drugs. Fast developing imaging technologies, such as modern optical coherence tomography, unlocked multiple new approaches, offering the potential for in vivo study of the vitreous structure. They allowed to analyze in vivo a range of vitreous structures, such as posterior precortical vitreous pockets, Cloquet canal, channels that interconnect them, perivascular vitreous fissures, and cisterns. We provide an overview of such imaging techniques and their principles and of some challenges in visualizing vitreous structures. Finally, it explores the potential of combining the latest technologies and machine learning to enhance our understanding of vitreous structures.

Bilateral Subinternal Limiting Membrane Crystalline Deposits Secondary to Terson Syndrome.

Background: We report the case of bilateral, subinternal limiting membrane crystalline deposits in a patient with Terson syndrome, describe the possible pathogenesis, and highlight management. Case Presentation. A 24-year-old male with a history of traumatic massive parenchymal and subdural frontal hemorrhage presented to our clinic seven months after a motor vehicle accident, prolonged hospitalization, and rehabilitation, complaining of decreased vision in both eyes. The Snellen visual acuity was 1/60 in the right eye, and 6/60 in the left eye. Fundus examination showed an organized white vitreous hemorrhage in both eyes with almost no view of the retina. The anterior segments were normal. He underwent a 25-gauge pars plana vitrectomy in both eyes. During the surgery, golden crescent-shaped sediment consisting of small crystals was observed under the internal limiting membrane in both eyes: anterior to the inferior temporal vascular arcade in the right eye and posterior to it in the left eye. Internal limiting membrane (ILM) peeling after staining with ILM-blue dye was performed in the left eye, where the finding involved the macula. One year after the surgery, visual acuity significantly improved to 6/8.5 on the right and 6/6 on the left. Epiretinal membrane formation was observed in the right eye, where ILM peeling was not performed. Conclusion: Subinternal limiting membrane crystalline deposit finding is a rare condition. Consider performing internal limiting membrane peeling and sediment removal in cases with macular involvement. In cases where crystals are concentrated outside of the macula, follow-up may be considered.

Predictors of Clinic Attendance After Community-Based Vision Screening.

Purpose: The purpose of this study was to analyze appointment attendance rates and patient characteristics associated with follow-up adherence after referral from a community vision screening event. Methods: A retrospective chart review of patients who attended a 2021 or 2022 community vision screening event and were referred to the university clinic for further care. Appointments were offered without charge and scheduled at the event. Associations between patients' clinical and demographic characteristics and appointment attendance were assessed by binary logistical regression. Results: A total of 935 patients attended the annual community vision screening events held in 2021 and 2022. Of these patients, 117 (13%) were referred to the clinic for follow-up, of whom 56 (48%) attended their scheduled follow-up appointment. The most common reasons for clinic referral included cataract (12, 10%), diabetic retinopathy (11, 9%), glaucoma (9, 8%), and challenging refractive error (9, 8%). Health insurance and male gender were predictors of follow-up (odds ratio [OR] = 3.08, 95% confidence interval [CI] = 1.19-7.99, P = 0.021 and OR = 2.72, 95% CI = 1.10-6.61, P = 0.035, respectively). Conclusions: Half of the referred patients followed up after vision screening. Providing appointment scheduling at the point of care and offering follow-up care at no cost may help to promote clinic follow-up, but further assessment of barriers to regular eye care is warranted. Health insurance most strongly predicted successful clinic attendance. Translational Relevance: This study emphasizes the enduring impact of health insurance status as a barrier to accessing comprehensive vision care.

A Scleral Buckle Infection Caused by Cutibacterium Acnes (formerly Propionibacterium Acnes) Following An Atypical, Indolent Course.

PURPOSE: To report a case of atypical, indolent presentation of scleral buckle infection, caused by Cutibacterium acnes (formerly known as Propionibacterium acnes). METHODS: Observational case report. RESULTS: A 44-year-old healthy female with a history of scleral buckling procedure for retinal detachment repair sixteen years prior to presentation, was admitted with pain and redness in her left eye for six weeks. Conjunctival hyperemia and vascular congestion were noted over the scleral buckle in a circular manner without signs of exposure. After removal of the scleral buckle, cultures analysis revealed Cutibacterium acne. Systemic Amoxicillin was administrated. Over a 6-months follow-up, the retina remained attached. CONCLUSION: C. acne, known to be associated with chronic postoperative endophthalmitis after cataract surgery, may also lead to scleral buckle infection with an indolent, chronic course.

Postponed care due to COVID-19 lockdown impact on visual acuity of retinal vein occlusion patients: a large cohort.

PURPOSE: To evaluate the impact of postponed care attributed to coronavirus disease (COVID-19) pandemic lockdowns on visual acuity and the number of anti-VEGF injections in patients with retinal vein occlusion (RVO). METHODS: A multicenter, retrospective study of consecutive RVO patients previously treated with anti-VEGF injections, which compared data from pre- (2019) and during (2020) COVID-19 lockdown period. RESULTS: A total of 814 RVO patients with a mean age of 72.8 years met the inclusion criteria. Of them, 439 patients were assessed in 2019 and 375 in 2020. There was no significant difference between the COVID-19 and pre-COVID-19 period in terms of baseline and final BCVA (p = 0.7 and 0.9 respectively), but there was a significantly reduced mean number of anti-VEGF injections during the COVID-19 period (5.0 and. 5.9 respectively, p < 0.01), with a constant lower ratio of injections per patient. A noticeable decline was found during March-May (p < 0.01) in 2020. Baseline BCVA (0.69, p < 0.01) and the number of injections (- 0.01, p = 0.01) were predictors of final BCVA. CONCLUSIONS: In a large cohort of RVO patients, during 2020 lockdowns imposed due to the COVID-19 pandemic, a significant reduction in the annual number of anti-VEGF injections was noted. The postponed care did not result in a significant impact on the final BCVA. Baseline BCVA and the number of annual injections serve as predictors for final BCVA in RVO patients.

Optical Coherence Tomography Prognostic Factors in Age-Related Macular Degeneration Patients with Peripapillary Choroidal Neovascularization.

PURPOSE: The aim of the study was to investigate the correlation between optical coherence tomography (OCT) findings and visual acuity outcomes after treatment with intravitreal bevacizumab (IVB) injections for age-related macular degeneration (AMD) patients with peripapillary choroidal neovascularization (PPCNV). METHODS: The study involved a retrospective case series of consecutive patients diagnosed with PPCNV secondary to AMD. All patients were treated with IVB injections with a follow-up time of 1 year. Data collected included best-corrected visual acuity (BCVA) and automated and manually measured OCT parameters. RESULTS: A total of 68 eyes were diagnosed with PPMV. Of them, 30 eyes of 30 patients aged 84.3 ± 6.9 years of which 63.3% female gender were included. Baseline BCVA was 0.46 ± 0.62 logMAR (Snellen 20/57), average choroidal thickness was 193.2 ± 22 µm, and mean number of IVB injections was 7.2 ± 1.9. After 1 year, BCVA was 0.56 ± 0.78 logMAR (Snellen 20/72) (p = 0.28). Eyes with greater central retinal thickness (r = -0.36, p = 0.05), greater subretinal hyper-reflective material (SHRM) area (r = -0.37, p = 0.05), and greater sub-retinal fluid (SRF) area (r = -0.73, p < 0.001) had a significantly smaller improvement in BCVA. Eyes with pigment epithelium detachment (PED) (0.68 ± 0.90 vs. 0.21 ± 0.12, p = 0.03) had a significantly worse BCVA. CONCLUSIONS: Our data suggest that AMD-related PPCNV with greater foveal thickness, PED size, SHRM, and SRF areas have worse final BCVA prognosis.

Detection of Intraorbital Foreign Bodies Using Magnetic Resonance Imaging and Computed Tomography.

PURPOSE: We analyze the detectability of intraorbital foreign bodies (OrbFBs) of various types and sizes using computed tomography (CT) and magnetic resonance imaging using a three-Tesla machine (MRI 3 T). METHODS: An ex vivo model of sheep eyes with preserved extraocular muscles and orbital fat tissue placed in the orbital cavity of the human skull was created for this study. Foreign bodies made of four different materials - plastic, bottle glass, stone and wood - each in three different sizes (large, intermediate and small) were inserted into the soft tissue of the orbit in the extraocular space. Each orbit was scanned by CT and MRI. Images were analyzed by a senior radiologist and underwent masked review by three oculoplastic surgeons. RESULTS: Analysis of MRI and CT scans identified distinguishing characteristics for each of the four materials. This information was further integrated into a clinical algorithm. CT allowed easier identification of most of the embedded materials compared to MRI. Smaller OrbFB size was associated with lower detectability. Review of CT yielded 94.4% agreement between oculoplastic specialists in detecting OrbFbs using CT scans and allowed detection of most OrbFBs. In contrast, the overall agreement with MRI was lower: 66.7% with T1 MPRAGE, 50% with T1TSE, 88.9% with T2 TSE and 72.2% with T2 TSE FS. Plastic was the most difficult material to detect in all size categories. CONCLUSIONS: CT offers a clear advantage over MRI for detecting and localizing nonmetallic OrbFBs of all sizes, except for plastic. Plastic OrbFBs can be detected with CT depending on size but are more visible in MRI scans.

The Role of Anterior Chamber Depth on Post-operative Refractive Error After Phacovitrectomy.

PURPOSE: To investigate the effect of phacovitrectomy on the post-operative anterior chamber depth (ACD) and refractive outcomes, and to analyze the potential differences between vitreous filling with BSS, air and gas. METHODS: Patients who underwent phacovitrectomy were included in this study and invited for repeated post-operative examination including refraction and biometry at least 3 months after the surgery. Data retrieved included demographic information, indication for phacovitrectomy, surgical details, type of vitreous filling (BSS, air or gas), pre-operative and post-operative biometric data including K-readings, axial length (AL), and ACD, as well as spherical equivalent (SE) values of the target and final refraction. RESULTS: Forty-three eyes of 43 patients were included in this study, including 10 eyes filled with BSS, 18 with air and 15 with gas. The mean difference between the final measured spherical equivalent (SE) and the SE of the intended target refraction was 0.61±0.68 D (p = 0.019). Only 58.1% of eyes had a final SE within ±0.5D of the target refraction. Following surgery, AL remained unchanged, while mean pre-operative ACD increased significantly from 3.11±0.34 mm to 4.77±0.47 mm (p < 0.001). There was no difference in refractive error between the vitreous fillings and no correlation with AL or ACD. CONCLUSIONS: Phacovitrectomy is associated with lower accuracy of post-operative refraction compared to cataract surgery. This may be attributed to a significant change in ACD, influencing the effective lens position of the IOL, and may require adjustment of the pre-operative calculations.

Safety of 3 Tesla Magnetic Resonance Imaging on iStent Implants: An Ex-Vivo Study.

PRCIS: Our study shows that iStent implant does not cause significant image artifacts, heating, or displacement during magnetic resonance imaging (MRI) scan. This device can be safely used in patients undergoing MRI scans using 3 Tesla (3T) machines. PURPOSE: The iStent is a medical grade titanium implant commonly implanted in the anterior chamber angle of glaucomatous eyes in order to reduce intraocular pressure and medication burden. As many people now have these devices implanted in their eyes, the issue of their compatibility with MRI in terms of safety and interference with interpretation of these studies commonly arises. The purpose of this study is to evaluate the safety of 3T MRI scans in eyes that have undergone iStent implantation and to assess the interference of the implant to the scan interpretation. MATERIALS AND METHODS: An ex vivo model of sheep eye with an iStent and proximately placed heat detector probe was used to study changes in the temperature during MRI 3T scan. The study included 2 fresh eyes with preserved extraocular muscles and orbital fat tissue placed in the orbital cavity of a human skull. Each eye with orbital content was scanned with a 3T MRI machine. RESULTS: No displacement of the implant was observed during MRI scanning. The heat detector showed mild temperature elevation during the first minutes of the scan from 14.6 to 16.5°C. The iStent was best visualized in T2 turbo spin echo sequences and showed no significant artifacts. CONCLUSION: iStent implants did not move during the MRI scan, showed minimal interaction with the magnetic field in terms of heating and image distortion. These interactions were not strong enough to present a substantial risk to patients with this implant undergoing an MRI scan.

Correlation of Response between Both Eyes to First- and Second-Line Anti-VEGF Therapy in Diabetic Macular Edema.

PURPOSE: To evaluate the anatomical correlation between fellow eyes for bilateral second-line anti-VEGF treatment in eyes with bilateral diabetic macular edema (DME) with incomplete response to first-line bevacizumab therapy. METHODS: Seventy-four eyes (n = 37 patients) with bilateral-DME having incomplete response to first-line bevacizumab therapy that were switched for bilateral treatment with ranibizumab were retrospectively evaluated. Data collected included demographics, visual acuity and macular thickness. We evaluate the correlation for the response of both eyes in terms of macular thickness and visual acuity. RESULTS: The mean±SD age was 76 ± 8 years. The mean±SD number of bevacizumab injections prior the switch was 11.03 ± 5.1 in the first eye (FE) and 10.9 ± 5.2 in the second eye (SE). The central subfield thickness (CST) reduced from 472 ± 171 microns at baseline to 418 ± 161 after the last bevacizumab injection and 365 ± 74 after 3 ranibizumab injections in the FE (p = .016, p = .004, respectively), and from 463 ± 145 microns to 446 ± 123, and 421 ± 103 in the SE (p = .112, p = .001, respectively). There was strong positive correlation between the eyes for the CST reduction under bevacizumab and ranibizumab treatments in each visit. BCVA± SD at baseline was 0.41 ± 0.30 LogMAR in the FE, and 0.42 ± 0.29 in the SE (p = .44). After 3 injections of bevacizumab, the BCVA was 0.37 ± 0.26 and 0.42 ± 0.23 in FE and SE respectively (p = .013, p = .132, respectively). CONCLUSIONS: This study demonstrated a strong anatomical correlation responses between the eyes in patients with bilateral DME for both first-line bevacizumab therapy and second-line ranibizumab therapy. Response to second-line therapy was favorable and correlated among eyes regardless they were from the same or different individuals.

Study of wetting of the animal retinas by Water and organic liquids and its Implications for ophthalmology.

Interfacial properties of the animal retinas are reported. Wetting of the retina-retinal pigment epithelium-choroid-sclera tissues of cow, sheep, and pig eyes by water, silicone and castor oil was explored experimentally. Both water and silicone oils demonstrated complete wetting of the retina, regardless of the viscosity of the silicone oil, whereas the castor oil demonstrated a partial wetting regime. Similar wetting regimes were observed for sheep, cow and pig retinas. The intact surface of animal retina was found to be both hydrophilic and oleophilic. Wetting experiments with double sandwich oil/water layers were performed. Water demonstrated stronger affinity to the retina than silicone and castor oils, and eventually replaced the oils at the liquid/retina interface. We conclude that aqueous solutions continuously secreted in the living eye may displace silicone oil from the retinal surface and contribute to retinal re-detachment. Study of dynamics of wetting of the animal retina by water and organic oils is reported. The exponent describing the dynamics of spreading of the castor oil is lower than that predicted by the Tanner law. Castor oil may provide more effective tamponade than silicone oil.

Massive Orbital Myiasis Caused by Sarcophaga argyrostoma Complicating Eyelid Malignancy.

Purpose. To report a case of massive orbital myiasis caused by the larvae of Sarcophaga argyrostoma, complicating eyelid malignancy. Observations. A 98-year-old man first presented to our clinic noted to have a fast-growing lesion on his right upper and lower eyelids. Squamous cell carcinoma of the eyelids was highly suspected, and surgical excision was advised, but the patient refused any surgical or nonsurgical intervention. For the next eight months, the patient's family members continued to observe a high rate of tumor growth accompanied by deterioration of the general condition. During this whole period, the patient rejected admission to the hospital and was observed by nursing home staff. He was admitted to the emergency room in cachexic, unresponsive condition with fetid discharge and multiple live maggots crawling out from a large necrotic mass over the right orbit. On examination, no eyelids, eyeball, or other ocular tissue could be seen, while an extension of necrotic mass to forehead and midcheek was noted. Manual removal of larvae was performed. The patient passed away eight hours after his admission and larval removal. The maggots were identified as the third-instar larvae of Sarcophaga argyrostoma. Conclusions and Importance. This is the first reported case of home-acquired, massive orbital myiasis by S. argyrostoma. This case illustrates the crucial role of fly control as part of medical and home care in immobile patients. Moreover, it shows the importance of awareness by nursing home staff, paramedical, and medical personnel of possible myiasis, especially in bed-bound patients with skin malignancies and open wounds.

Posterior pole retinal tears following blunt ocular trauma.

PURPOSE: Posterior pole retinal tears occur rarely following blunt trauma. We describe a case of traumatic macular tears, without concurrent peripheral retinal tears or holes. OBSERVATIONS: A 17-year-old patient presented to our emergency unit with blunt ocular trauma and multiple maxillofacial fractures after being assaulted. On examination visual acuity was 20/200 in the left eye with scant vitreous and preretinal hemorrhages. Funduscopic examination revealed multiple choroidal ruptures running concentrically to the optic disc, a subretinal macular hemorrhage, and a large macular tear in the area of the inferior vascular arcade just temporal to the macula. Optical coherence tomography revealed subretinal fluid in the foveal area, choroidal ruptures and a slight elevation of the macular retinal tear margins without subretinal fluid. Laser retinopexy was performed around the macular tear nasally. On follow-up, the retina in the lasered area remained flat, while a shallow retinal detachment had developed temporal to the tear, with a second tear appearing supero-temporally to the macula. Laser retinopexy was not possible due to surrounding subretinal hemorrhage. The clinical course was later complicated by macular detachment, necessitating pars plana vitrectomy with endolaser around the posterior tears and the retinal periphery, and silicone oil injection. CONCLUSIONS: While traumatic macular holes and traumatic macular choroidal ruptures have both been extensively described, posterior pole and macular retinal tears following blunt trauma have rarely been reported. This case illustrates this unusual finding, discussing the possible pathogenic mechanisms and the importance of close follow-up of patients after blunt trauma with appropriate imaging.

Acute angle closure in an aphakic infant: Case report and review of the literature.

PURPOSE: Aphakic pupillary block glaucoma is a rare complication after congenital cataract surgery. We describe the case of an infant with acute angle closure in an aphakic eye following congenital cataract lensectomy with anterior vitrectomy nine months prior. Potential pathophysiology and therapeutic strategies are discussed. OBSERVATIONS: A one-year-old male infant presented to our emergency unit with right eye injection and pain. At the age of six weeks he had undergone right eye lensectomy with anterior vitrectomy for congenital cataract and was left aphakic with large anterior and posterior capsulorrhexis. Examination was significant for a shallow anterior chamber centrally and iridocorneal touch of the periphery for 360° with intraocular pressure (IOP) measured at 70 mmHg. The child was diagnosed with aphakic pupillary block leading to an acute angle closure event. He underwent emergent anterior vitrectomy with surgical peripheral iridotomy (PI) performed via pars plana approach. This resulted in immediate deepening of the anterior chamber, with resolution of the pupillary block and iridocorneal touch. Thereafter, his ocular exam was normal. CONCLUSIONS AND IMPORTANCE: This unusual case underscores the importance of vigilance in the postoperative management of children after congenital cataract extraction. Unexpected complications remain a threat despite the initial undertaking of preventative measures.