Impact of inherited retinal diseases on Canadian patients and families: a mixed-methods study

OBJECTIVE

To understand the physical, psychosocial, and practical challenges faced by Canadian patients with inherited retinal diseases (IRDs) and their families.

DESIGN

Mixed methods.

PARTICIPANTS

A total of 408 Canadians living with or caring for someone with an IRD (mean age = 51.4 ± 16.7 years) completed an online survey. Twenty cohort respondents participated in additional telephone interviews.

METHODS

The online survey was comprised of questions concerning demographics, self-reported vision, genetic testing, information preferences, health care experiences, treatment goals, and disease impact on daily life. Recruitment occurred through Fighting Blindness Canada's community database. Survey dissemination also occurred via social media and not-for-profit stakeholder outreach. Subsequent to survey completion, a subset of respondents participated in semistructured telephone interviews to further elucidate illness experience.

RESULTS

Respondents identified having 1 of more than 14 IRDs, with 72% specifying retinitis pigmentosa. Sixty-eight percent reported being legally blind, and more than 85% self-reported moderate to low vision or worse. IRDs impacted daily functioning, with 53% of respondents indicating that they affected employment or education. Psychological challenges were evident, with more than 70% worried about coping with daily life and more than 60% indicating fear and stress. Qualitative data described hopelessness around suitable work, loss of independence, and challenges with social interaction. Sixty-five percent reported a negative impact on family life. Many had not accessed social support services because of a lack of perceived need, awareness, or availability.

CONCLUSION

Canadian patients with IRDs report moderate to severe visual impairment, and both patients and their families describe an impact on psychosocial well-being and functioning during daily activities. Vision rehabilitation with a psychosocial approach is necessary, alongside facilitating access to emerging treatments.

Resting state electroretinography: An innovative approach to intrinsic retinal function monitoring

The electroretinogram (ERG) represents the biopotential evoked by the retina in response to a light stimulus. The flash evoked ERG (fERG) is the ERG modality most frequently used clinically to diagnose and monitor retinal disorders. We hereby present a new method to record spontaneous retinal activity, without the use of a flash stimulus, that we named the resting-state ERG (rsERG). The recordings were done in normal subjects under light- and dark-adaptation and with different background light conditions (i.e., variations of wavelength and intensity). Additionally, rsERG recordings were obtained in five patients with retinopathies. The signals were subsequently analyzed in the frequency domain, extracting both periodic (i.e., frequency peaks) and aperiodic (i.e., background trend) components of the signal. The later was further assessed through a multifractal analysis using Wavelet Leaders. Results show that, irrespective of the recording conditions used, the rsERG always includes the same 90 Hz component; a frequency component also present in the fERG response, suggesting a retinally-intrinsic origin. However, in addition, the fERGs also includes a low-frequency component which is absent in the rsERGs, a finding supporting a retinally-induced origin. Comparing rsERGs with fERGs in selected patients with various retinal disorders indicates that the two retinal signals are not always similarly affected (either as a result of underlying retinal pathology or otherwise), suggesting an added value in the assessment of retinal function. Thus, the rsERG could have a similar role in clinical visual electrophysiology as that of the resting-state EEG in neurology namely, to quantify changes in spontaneous activity that result from a given disease processes.

Repair of Rhegmatogenous Retinal Detachment in Choroideremia Secondary to Posterior Extramacular Retinal Hole

Rhegmatogenous retinal detachment in choroideremia is a rare occurrence. The authors present a case of a 23-year-old man with choroideremia with a near-total rhegmatogenous retinal detachment. Fundus examination did not reveal any retinal breaks, but extensive preoperative optical coherence tomography detected a small posterior hole along the superior arcades. The retinal detachment was successfully managed with vitrectomy, perfluorooctane to confirm the absence of any peripheral breaks, endolaser, and 20% sulfur hexafluoride gas. Similar extramacular holes were found in the patient's other eye. Patients with choroideremia may develop posterior retinal breaks leading to retinal detachment.

Durability of VEGF Suppression With Intravitreal Aflibercept and Brolucizumab: Using Pharmacokinetic Modeling to Understand Clinical Outcomes

Purpose

To investigate whether vascular endothelial growth factor (VEGF)–suppression durations contribute to our understanding of clinical trial outcomes by simulating vitreous molar concentrations (C_vm) of intravitreal aflibercept (IVT-AFL) and brolucizumab (IVT-BRO) using pharmacokinetic (PK) modeling.

Methods

A PK model simulated C_vm after single-dose IVT-AFL, IVT-BRO, and ranibizumab (IVT-RAN), and extrapolated intraocular VEGF-suppression thresholds and durations. Vitreous PK after multidose regimens used in studies of IVT-AFL versus IVT-BRO were simulated and compared with best-corrected visual acuity (BCVA) data.

Results

C_vm peaked higher (C_max) and decreased more quickly to the VEGF-suppression threshold and minimum (C_min) levels with IVT-BRO than with IVT-AFL, consistent with their molar doses calculated using molecular weights and vitreous half-lives (26 kDa and 115 kDa; 4.4–5.1 and 9.1–11 days, respectively). The mean VEGF suppression durations were 71 days for IVT-AFL 2 mg and 51 (48–59) days for IVT-BRO 6 mg. Based on dosing in OSPREY (matched dosing to week [w]32 for both agents; thereafter, IVT-AFL every eight weeks [q8w] and IVT-BRO q12w for the last two doses [w32→w44 and w44→w56]), IVT-BRO showed wider C_max-C_min fluctuations than IVT-AFL. The IVT-BRO C_min fell below the VEGF-suppression threshold at timepoints near w56, when decreases in BCVA were also observed. The IVT-AFL vitreous C_min remained above the suppression threshold through w56, where BCVA gains were maintained.

Conclusions

The PK-modeled mean VEGF-suppression duration for IVT-BRO was substantially shorter than that published for IVT-AFL and may not be sufficient to effectively suppress VEGF throughout q12w dosing.

Translational Relevance

The PK modeling suggests that more patients may be maintained on ≥q12w dosing with IVT-AFL than with IVT-BRO.

Imaging Biomarkers and Their Impact on Therapeutic Decision-Making in the Management of Neovascular Age-Related Macular Degeneration

These recommendations, produced by a group of Canadian retina experts, have been developed to assist both retina specialists and general ophthalmologists in the management of vision-threatening neovascular age-related macular degeneration (nAMD). The recommendations are based on published evidence as well as collective experience and expertise in routine clinical practice. We provide an update on practice principles for optimal patient care, focusing on identified imaging biomarkers, in particular retinal fluid, as well as current and emerging therapeutic approaches. Algorithms for delivering high-quality care and improving long-term patient outcomes are provided, with an emphasis on timely and appropriate treatment to preserve and maintain vision. In the context of nAMD, increasing macular fluid or leakage on fluorescein angiography (FA) may indicate disease activity regardless of its location. Early elimination of intraretinal fluid (IRF) is of particular relevance as it is a prognostic indicator of worse visual outcomes. Robust referral pathways for second opinion and peer-to-peer consultations must be in place for cases not responding to intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy.

The Role of Telemedicine to Alleviate an Increasingly Burdened Healthcare System: Retinopathy of Prematurity

Telemedicine-based remote digital fundus imaging (RDFI-TM) offers a promising platform for the screening of retinopathy of prematurity. RDFI-TM addresses some of the challenges faced by ophthalmologists in examining this vulnerable population in both low- and high-income countries. In this review, we studied the evidence on the use of RDFI-TM and analyzed the practical framework for RDFI-TM systems. We assessed the novel technological advances that can be deployed within RDFI-TM systems including noncontact imaging systems, smartphone-based imaging tools, and deep learning algorithms.

Coats-like Exudative Vitreoretinopathy in Retinitis Pigmentosa: Ocular Manifestations and Treatment Outcomes

PURPOSE

To provide a comprehensive review of the ocular manifestations, outcomes, and genetic findings in patients with Coats-like retinitis pigmentosa (RP).

DESIGN

Multicenter, retrospective, nonconsecutive case series.

PARTICIPANTS

Patients with a diagnosis of RP demonstrating Coats-like exudative vitreoretinopathy between January 1, 2008, and October 1, 2019.

METHODS

Evaluation of ocular findings at RP diagnosis and at time of presentation of Coats-like exudative vitreoretinopathy, pedigree analysis, genetic testing, retinal imaging, and anatomic outcomes after treatment.

MAIN OUTCOME MEASURES

Visual acuity, ophthalmoscopy results, OCT results, fluorescein angiography results, and identification of genetic mutations.

RESULTS

Nine patients diagnosed with RP and demonstrating Coats-like exudative vitreoretinopathy were included. Median age at time of RP diagnosis was 8 years (range, 1-22 years), and median age at presentation of Coats-like exudative vitreoretinopathy was 18 years (range, 1-41 years). Seven patients were female, and 2 were male. The genetic cause of disease was identified in 6 patients. Three patients demonstrated Coats-like fundus findings at the time of RP diagnosis. Exudative retinal detachment (ERD) localized to the infratemporal periphery was present in all patients, with bilateral disease observed in 7 patients. In all treated patients, focal laser photocoagulation was used to treat leaking telangiectasias and to limit further ERD expansion. Cystoid macular edema refractory to carbonic anhydrase inhibitor therapy and ultimately amenable to treatment with intravitreal anti-vascular endothelial growth factor injection was observed in 4 patients.

CONCLUSIONS

Coats-like vitreoretinopathy is present in up to 5% of all RP patients. The term Coats-like RP is used colloquially to describe this disease state, which can present at the time of RP diagnosis or, more commonly, develops late during the clinical course of patients with longstanding RP. Coats-like RP is distinct from Coats disease in that exudative pathologic features occur exclusively in the setting of a coexisting RP diagnosis, is restricted to the infratemporal retina, can affect both eyes, and does not demonstrate a male gender bias. Given the risk of added vision loss posed by exudative vitreoretinopathy in patients with RP, a heightened awareness of this condition is critical in facilitating timely intervention.

Smartphone-Based, Rapid, Wide-Field Fundus Photography for Diagnosis of Pediatric Retinal Diseases

Purpose

An important, unmet clinical need is for cost-effective, reliable, easy-to-use, and portable retinal photography to evaluate preventable causes of vision loss in children. This study presents the feasibility of a novel smartphone-based retinal imaging device tailored to imaging the pediatric fundus.

Methods

Several modifications for children were made to our previous device, including a child-friendly 3D printed housing of animals, attention-grabbing targets, enhanced image stitching, and video-recording capabilities. Retinal photographs were obtained in children undergoing routine dilated eye examination. Experienced masked retina-specialist graders determined photograph quality and made diagnoses based on the images, which were compared to the treating clinician's diagnosis.

Results

Dilated fundus photographs were acquired in 43 patients with a mean age of 6.7 years. The diagnoses included retinoblastoma, Coats' disease, commotio retinae, and optic nerve hypoplasia, among others. Mean time to acquire five standard photographs totaling 90-degree field of vision was 2.3 ± 1.1 minutes. Patients rated their experience of image acquisition favorably, with a Likert score of 4.6 ± 0.8 out of 5. There was 96% agreement between image-based diagnosis and the treating clinician's diagnosis.

Conclusions

We report a handheld smartphone-based device with modifications tailored for wide-field fundus photography in pediatric patients that can rapidly acquire fundus photos while being well-tolerated.

Translational Relevance

Advances in handheld smartphone-based fundus photography devices decrease the technical barrier for image acquisition in children and may potentially increase access to ophthalmic care in communities with limited resources.

Peripheral Visual Fields in ABCA4 Stargardt Disease and Correlation With Disease Extent on Ultra-widefield Fundus Autofluorescence

PURPOSE

To evaluate the disease extent on ultra-widefield fundus autofluorescence (UWF-FAF) in patients with ABCA4 Stargardt disease (STGD) and correlate these data with functional outcome measures.

DESIGN

Retrospective cross-sectional study.

METHODS

Setting: Kellogg Eye Center, University of Michigan.

STUDY POPULATION

Sixty-five patients with clinical diagnosis and proven pathogenic variants in the ABCA4 gene. Observational Procedures: The UWF-FAF images were obtained using Optos (200 degrees) and classified into 3 types. Functional testing included kinetic widefield perimetry, full-field electroretinogram (ffERG), and visual acuity (VA). All results were evaluated with respect to UWF-FAF classification.

MAIN OUTCOME MEASURES

Classification of UWF-FAF; area comprising the I4e, III4e, and IV4e isopters; ffERG patterns; and VA.

RESULTS

For UWF-FAF, 27 subjects (41.5%) were classified as type I, 17 (26.2%) as type II, and 21 (32.4%) as type III. The area of each isopter correlated inversely with the extent of the disease and all isopters were able to detect differences among UWF-FAF types (IV4e, P = .0013; III4e, P = .0003; I4e, P < .0001 = 3.93e^-8). ffERG patterns and VA were also different among the 3 UWF-FAF types (P < .001 = 6.61e-⁶ and P < .001 = 7.3e^-5, respectively).

CONCLUSION

Patients with widespread disease presented with more constriction of peripheral visual fields and had more dysfunction on ffERG and worse VA compared to patients with disease confined to the macula. UWF-FAF images may provide information for estimating peripheral and central visual function in STGD.

Confluent Endpoint Subthreshold Argon Laser for Serous Macular Detachment in Tilted Disc Syndrome Refractory to Anti-VEGF

A 70-year-old woman presented with 20/200 visual acuity in the right eye. Multimodal imaging revealed tilted disc syndrome (TDS) with macular serous detachment (MSD) and pigmentary changes at the temporal margin of the optic disc. Subretinal fluid persisted after three monthly intravitreal bevacizumab (Avastin; Genentech, South San Francisco, CA) injections and threshold focal laser photocoagulation. Subsequently, confluent subthreshold argon laser was applied over the entire area of retinal pigment epithelium (RPE) abnormalities, resulting in the resolution of subretinal fluid without recurrence through 3 years of follow-up. Subthreshold argon laser treatment may serve as a therapeutic option for MSD in TDS. Targeting leakage sites and stimulating RPE cells might help absorb subretinal fluid. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:760-763.].

Double hyperautofluorescent ring on fundus autofluorescence in ABCA4

We report an unusual phenotype in a child with a clinical diagnosis of recessive Stargardt disease (STGD1) and two pathogenic variants in the ABCA4 gene. Typically, the diagnosis of early-onset STGD1 is challenging because children may present with a variety of fundus changes and a variable rate of progression. At the time of his initial visit, the 6-year-old boy presented with 20/200 OD (right eye) and 20/150 OS (left eye), symmetrical mild foveal atrophy without flecks on fundus exam, and foveal hypoautofluorescence surrounded by a homogeneous hyperautofluorescent background on wide-field fundus autofluorescence. Over 4 years of follow-up, the retinal atrophy continued to progress, resulting in two well-defined and concentric hyperautofluorescent rings: one ring located at the posterior pole and the other located around the peripapillary region. Visual acuity also deteriorated to counting fingers at 4ft OD and 20/500 OS. To the best of our knowledge, this phenotype has not been previously described with the ABCA4 gene.

Prevention of Proliferative Vitreoretinopathy by Suppression of Phosphatidylinositol 5-Phosphate 4-Kinases

Purpose

Previous studies have shown that vitreous stimulates degradation of the tumor suppressor protein p53 and that knockdown of phosphatidylinositol 5-phosphate 4-kinases (PI5P4Kα and -β) abrogates proliferation of p53-deficient cells. The purpose of this study was to determine whether vitreous stimulated expression of PI5P4Kα and -β and whether suppression of PI5P4Kα and -β would inhibit vitreous-induced cellular responses and experimental proliferative vitreoretinopathy (PVR).

Methods

PI5P4Kα and -β encoded by PIP4K2A and 2B, respectively, in human ARPE-19 cells were knocked down by stably expressing short hairpin (sh)RNA directed at human PIP4K2A and -2B. In addition, we rescued expression of PI5P4Kα and -β by re-expressing mouse PIP4K2A and -2B in the PI5P4Kα and -β knocked-down ARPE-19 cells. Expression of PI5P4Kα and -β was determined by Western blot and immunofluorescence. The following cellular responses were monitored: cell proliferation, survival, migration, and contraction. Moreover, the cell potential of inducing PVR was examined in a rabbit model of PVR effected by intravitreal cell injection.

Results

We found that vitreous enhanced expression of PI5P4Kα and -β in RPE cells and that knocking down PI5P4Kα and -β abrogated vitreous-stimulated cell proliferation, survival, migration, and contraction. Re-expression of mouse PIP4Kα and -β in the human PI5P4Kα and -β knocked-down cells recovered the loss of vitreous-induced cell contraction. Importantly, suppression of PI5P4Kα and -β abrogated the pathogenesis of PVR induced by intravitreal cell injection in rabbits. Moreover, we revealed that expression of PI5P4Kα and -β was abundant in epiretinal membranes from PVR grade C patients.

Conclusions

The findings from this study indicate that PI5P4Kα and -β could be novel therapeutic targets for the treatment of PVR.

Cystoid macular changes on optical coherence tomography in a patient with maternally inherited diabetes and deafness (MIDD)-associated macular dystrophy

The clinical presentation and optical coherence tomography findings in a patient with maternally inherited diabetes and deafness (MIDD) are presented to highlight the presence of macular cystoid spaces in some patients with this disease. Typically, patients with MIDD demonstrate progression of a pigmentary maculopathy into areas of geographic macular atrophy. At the time of initial visit, the 30-year-old patient had large macular cystoid changes in addition to retinal pigmentary changes in both eyes. The cystoid changes responded to treatment with systemic immunosuppression and a topical carbonic anhydrase inhibitor (CAI), recurred when treated with topical CAI monotherapy, and finally resolved after an intravitreal triamcinolone acetonide injection. Over time, the retinal atrophy continued to progress, but the macular cysts did not recur. The patient received systemic immunosuppression for renal transplantation due to renal failure resulting from focal glomerulosclerosis. There was no evidence of diabetic retinopathy at any time during the five-and-a-half-year follow-up, and the patient retained good visual acuity in both eyes.

Occult Perforating Globe Injury Caused by Intraocular Foreign Body

Intraocular foreign bodies (IOFBs) may be associated with occult exit wounds. The authors present a case of a man who sustained a zipper-tooth IOFB through the cornea from a car tire explosion. CT showed an IOFB within the vitreous cavity, but the IOFB was not identified during vitrectomy. Extension of the peritomy revealed an exit wound with the foreign body lodged in the extraocular space. This case demonstrates that IOFBs can rest within the vitreous cavity after creating an exit wound, but may escape detection by being driven back out of the globe during vitrectomy due to the pressurized eye. Coexistent ocular surface and intraocular pathology often limit intraoperative visualization, but a perforating through-and-through injury should be suspected if the IOFB cannot be identified during vitrectomy. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:1162-1163.].

Choroidal and Retinal Abnormalities by Optical Coherence Tomography in Endogenous Cushing's Syndrome

CONTEXT

Cortisol has been suggested as a risk factor for choroidal thickening, which may lead to retinal changes.

OBJECTIVE

To compare choroidal thickness measurements using optical coherence tomography (OCT) in patients with endogenous active Cushing's syndrome (CS) and to evaluate the occurrence of retinal abnormalities in the same group of patients.

DESIGN

Cross-sectional study.

SETTING

Outpatient clinic.

PATIENTS

Eleven female patients with CS in hypercortisolism state as determined by the presence of at least two abnormal measurements from urinary cortisol 24 h, no suppression of cortisol with low dose dexamethasone suppression test, and nocturnal salivary cortisol levels and 12 healthy controls.

METHODS

Choroidal and retinal morphology was assessed using OCT.

MAIN OUTCOME MEASURES

Choroidal thickness measurements and the presence of retinal changes.

RESULTS

The mean subfoveal choroidal thickness was 372.96 ± 73.14 µm in the patients with CS and 255.63 ± 50.70 µm in the control group (p < 0.001). One patient (9.09%) presented with central serous chorioretinopathy and one patient (9.09%) with pachychoroid pigment epitheliopathy.

CONCLUSION

Choroidal thickness is increased in the eyes of patients with active CS compared to healthy and matched control. Also, 18.18% of patients presented with macular changes, possibly secondary to choroidal thickening. While further studies are necessary to confirm our findings, excess corticosteroid levels seem to have a significant effect on the choroid and might be associated with secondary retinal diseases.

The impact of cataract surgery on AMD development and progression

Age-related macular degeneration (AMD) and cataract are two leading causes of visual impairment worldwide which often occur concurrently in the same patient. With more than 1.6 million cataract operations performed per year in the United States, many of which occur in the nearly 1.75 million individuals diagnosed with AMD, there is ample incentive to further explore the interaction between these two conditions. Notably, the role of cataract surgery on AMD development and progression is of particular interest. This review summarizes the major findings from literature focusing on the effect of cataract surgery on AMD.

Omega-3 supplementation combined with anti-vascular endothelial growth factor lowers vitreal levels of vascular endothelial growth factor in wet age-related macular degeneration

PURPOSE

To determine the influence of omega-3 supplementation on vitreous vascular endothelial growth factor A (VEGF-A) levels in patients with exudative age-related macular degeneration (wet AMD) receiving intravitreal anti-VEGF treatment.

DESIGN

Prospective, randomized, open-label, single-center, clinical trial, consecutive interventional case series.

METHODS

The study included 3 cohorts with wet AMD and a control group with epiretinal membrane or macular hole. Twenty wet AMD patients being treated with anti-VEGF were randomized to daily supplementation of antioxidants, zinc, and carotenoids with omega-3 fatty acids (docosahexaenoic acid and eicosapentaenoic acid; group 1, n = 10) or without omega-3 fatty acids (group 2, n = 10). They were compared with an anti-VEGF treatment-naïve wet AMD group (group 3, n = 10) and an epiretinal membrane or macular hole group (group 4, n = 10). Primary outcome was vitreal VEGF-A levels (at the time of anti-VEGF injection). Secondary outcomes were plasma VEGF-A and central foveal thickness. Patients with new submacular hemorrhage or any other treatment within 3 months were excluded. Final analyses included 9, 6, 7, and 8 patients in groups 1 through 4, respectively.

RESULTS

Patients receiving omega-3s (group 1) had significantly lower levels of vitreal VEGF-A (141.11 ± 61.89 pg/mL) when compared with group 2 (626.09 ± 279.27 pg/mL; P = .036) and group 3 (735.48 ± 216.43 pg/mL; P = .013), but similar levels to group 4 (235.81 ± 33.99 pg/mL; P=.215). All groups showed similar values for plasma VEGF-A and central foveal thickness measurements.

CONCLUSIONS

This study demonstrated that omega-3 supplementation combined with anti-VEGF treatment is associated with decreased vitreal VEGF-A levels in wet AMD patients.

Evaluation of the vitreous microbial contamination rate in office-based three-port microincision vitrectomy surgery using Retrector technology

Background

To perform a microbiological contamination analysis of the vitreous during office-based micro-incision vitrectomy surgery (MIVS) assessing whether the bacteria detected correlated with patient's ocular conjunctival flora.

Methods

This is a prospective, interventional, nonrandomized case series of patients undergoing office-based MIVS, anti-VEGF, and dexamethasone intravitreal injections (triple therapy) for the treatment of wet age-related macular degeneration (AMD) and diabetic macular edema (DME).

All patients were operated at a small procedure room in an ambulatory clinic of the Department of Ophthalmology, University of Montreal, Quebec, Canada. Conjunctival samples were done before placing the sclerotomies. The MIVS was done with a 23-gauge retractable vitrector, a 27-gauge infusion line, and a 29-gauge chandelier. Undiluted and diluted vitreous were collected for aerobic, anaerobic and fungal cultures. Outcomes measured were bacterial species identification within samples collected from the conjunctiva and the vitreous.

Results

Thirty-seven patients (37 eyes) were recruited and completed over 17 months of follow-up. Twenty-eight had wet AMD and nine had DME. There were 13 men and 24 women, with a mean age of 78 years. Eighteen patients (46%) had culture positive conjunctival flora. Twenty-six bacterial colonies were tabulated in total from the conjunctival swabs. All bacteria detected were gram-positive bacteria (100%), most commonly: Staphylococcus epidermitis in 11 (42%) and Corynebacterium sp. in 6 (23%). Only 1/18 patients had more than 3 species isolated, 6/18 patients had 2 species and 11/18 patients had 1 species identified on the conjunctival swab. Only 1 of the 37 undiluted midvitreous samples was culture positive, equating to a contamination rate of 2.7%. None of the diluted vitreous samples were culture positive. All cultures were negative for fungus. No serious postoperative complications occurred, including bacterial endophthalmitis, choroidal detachment, and retinal detachment.

Conclusion

This preliminary study of office-based MIVS gives us insights on the ocular surface microbial profile and vitreous contamination rate of performing such procedures outside the OR-controlled environment. Our initial results seem to indicate that there is little risk of bacterial translocation and contamination from the conjunctiva into the vitreous. Therefore, if endophthalmitis occurs post-operatively, the source may likely arise after the procedure. Larger studies are needed to confirm our data.

Fibrovascular ingrowth after 25-gauge transconjunctival vitrectomy in proliferative diabetic retinopathy

The authors describe two patients with proliferative diabetic retinopathy bilaterally who were treated with transconjunctival 25-gauge pars plana vitrectomy (PPV) for dense vitreous hemorrhage (VH). After 4 and 10 months, respectively, both developed recurrent VH. They were initially managed with in-office gas-fluid exchange and anti-VEGF intravitreal injection. Soon after gas bubble resorption, the VH recurred. Color external photos revealed engorged episcleral vessels superotemporally, and ultrasound biomicroscopy confirmed the presence of fibrovascular ingrowth (FVI) at the sclerotomy site in both patients. They were successfully treated with a slightly modified 25-gauge PPV technique. Although FVI is well-recognized following conventional 20-gauge vitrectomy, this report is the first to detail FVI arising after small-gauge transconjunctival vitrectomy.

Tractional Maculopathies in Age-related Macular Degeneration

Age-related macular degeneration (AMD) is the leading cause of blindness among the elderly in developed countries. Much progress has been and continues to be made in search of better visual outcomes for dry and exudative AMD. Over the past decade, the importance of vitreomacular attachments has been recognized in AMD. In this article, we better characterize and describe vitreomacular and photoreceptor-retinal pigment epithelium interface relationships in AMD among treated and untreated patients and describe the surgical options available as well as their outcomes and possible complications.

Characterization of Electronic Spectra of Rhodium Monohydride and Monodeuteride

The electronic spectra of rhodium monohydride and monodeuteride, obtained using a molecular beam laser vaporization source, have been investigated from 400 to 500 nm, by laser excitation and dispersed fluorescence spectroscopies. The ground level of RhH is (3)Delta(3) with omega(e) approximately 2040 cm(-1) and omega(e)x(e) approximately 46 cm(-1). The corresponding RhD data are omega(e) approximately 1422 cm(-1) and omega(e)x(e) approximately 18 cm(-1). The estimated ground state bond length is r(0) = 0.159 nm. Excited states with Omega = 2, 3, and 4 have been observed. Copyright 2000 Academic Press.

Electronic Spectroscopy of Rhodium Mononitride

We report the first observation of gas-phase electronic spectra for rhodium mononitride. The RhN molecules have been produced in the reaction of laser-ablated rhodium metal with ammonia. Many vibronic bands have been studied in the 400-700 nm region using laser-induced fluorescence. Rotational analyses of the stronger of these, together with excited state lifetime measurements and Rh(14)N-Rh(15)N isotopic shifts, identify three electronic systems in the region: [15.1]1-X(1)Sigma(+), [19.5]0(+)-X(1)Sigma(+), and [22.4]0(+)-X(1)Sigma(+) with (0, 0) bands near 15 071, 19 489, and 22 385 cm(-1), respectively. The (1)Sigma(+) symmetry for the ground state agrees with theoretical predictions. Dispersed fluorescence spectra have been recorded which reveal the presence of electronic states at T = 553, 1740, and 3920 cm(-1). Copyright 2000 Academic Press.

The Electronic Structure and Spectrum of RhC: New Bands in the 400-500 nm Region, Interacting (2)Sigma(+) and (2)Pi States, and Deperturbation

Rhodium monocarbide (RhC) molecules were generated using a laser ablation/supersonic molecular beam source. Laser-induced and dispersed-fluorescence (DF) techniques were used to study the visible spectrum between 400 and 530 nm. Rh(12)C/Rh(13)C isotope shifts, DF, and excited level lifetime measurements assisted in classifying the observed bands into three series: the known C(2)Sigma(+) <-- X(2)Sigma(+) system (short excited state lifetimes) and the two spin subsystems of a (2)Pi(i) <-- X(2)Sigma(+) transition (long excited state lifetimes). A time-filtering technique was employed to separate effectively emission from close-lying (2)Pi and C(2)Sigma levels. The C-X system is inherently strong; the (2)Pi(i) <-- (2)Sigma(+) system very weak. The (2)Pi(1/2) <-- (2)Sigma component is identified with the B-X system, previously taken to be of (2)Sigma(+) <-- (2)Sigma(+) symmetry. The (2)Pi(3/2) component gives rise to local perturbations in the C state. Many new bands in the (2)Pi(i) <-- X(2)Sigma(+) transition were recorded and analyzed and the interactions/perturbations among the (2)Sigma(+) and the newly established (2)Pi(i) states were examined in detail. We calculated many spectroscopic constants and other properties associated with the perturbed (mixed) levels of the (2)Pi(1/2) and (2)Sigma(+) states and compared them with the experimental data. In most of the comparisons, the calculated values are in quantitative agreement with the experimental ones. Calculations of the spin-rotation constants of the (2)Sigma(+) and the Lambda-doubling constants of the (2)Pi(1/2) suggest the involvement of remote perturbers. Theory and experiment suggest that the electronic state labels of Scullman and Kaving [J. Mol. Spectrosc. 32, 475 (1969)], i.e., A(2)Pi(r), B(2)Sigma(+), C(2)Sigma(+), and D(2)Sigma(-), should be relabeled B(2)Pi(r), D(2)Pi(3/2), E(2)Sigma(+), and D(2)Pi(1/2), respectively. Copyright 1999 Academic Press.