Thomas R Friberg’s research while affiliated with University of Pittsburgh and other places

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Publications (141)


Bilateral Idiopathic Multifocal Pigment Epithelial Detachments: A Case Series and Review of Literature
  • Article

May 2025

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7 Reads

Retina

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Sean Ghiam

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Jordan Safran

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[...]

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Purpose Description of longitudinal follow-up of 13 patients diagnosed with Idiopathic Multifocal Pigment Epithelial Detachments (IMPED), a rare condition first described by Gass et al., in 2005. Methods This retrospective case series included 13 patients in the first to sixth decades of life who presented with multiple bilateral PEDs, confirmed by Optical Coherence Tomography. Ancillary imaging included fundus autofluorescence and angiography to exclude alternative diagnoses such as Central Serous Chorioretinopathy and Polypoidal Choroidovasculopathy. Electrophysiology testing, including full-field electroretinography (FFERG) and electrooculography (EOG), assessed both retinal and pigment epithelium function. Visual acuity (VA) was documented over a mean follow-up of 6.5 years (range: 0.1–26.4 years). Results All patients demonstrated stable VA during follow-up. Electrophysiology was normal in tested patients (FFERG: 9/13, EOG: 7/13). Genetic testing (10/13) was non-diagnostic. Two patients (including a patient previously receiving anti-VEGF without exudation) exhibited outer retinal atrophy. One patient developed a choroidal neovascularization (CNV) during follow-up, which resolved with intravitreal aflibercept. Conclusion IMPED should remain a diagnosis of exclusion, confirmed after sufficient follow-up demonstrating no progression. While our study implies a generally favorable prognosis, continuous monitoring is necessary to assess long-term risks, including potential complications such as the development of CNV and/or atrophy.


Examples of algorithm calculations for four patients demonstrating a raw OCT scan (top row), OCT with the RNFL marked in red (middle row) and an OCT with the entire retina marked in green (bottom row). The RR is calculated as the ratio between the mean reflectance of the area delineated in the middle row in red (RNFL) divided by the mean reflectance of the area delineated in the bottom row in green (the entire retina). Examples include RP patients in (A–C) with (A) RHO mutation, RR = 1.16; (B) RPGR mutation, RR = 1.32; (C) USH2A mutation, RR = 1.27; (D) normally sighted control, RR = 1.69.
Correlation coefficients between the reflectivity ratio (RR) and visual acuity for the right ((A), upper panel) and the left ((B), lower panel) eyes.
Three-dimensional representation of the negative correlation of both age (A) and disease duration (B) with visual acuity for each eye. The main diagonal (transparent arrow) of the approximated plane through the scatterplot of age as a function of visual acuity for OD (x-axis) and OS (y-axis) demonstrates a downwards slope (higher VA for younger age and shorter disease duration for (A) and (B), respectively).
Correlation coefficients between visual acuity and ONL thickness for the right ((A), upper panel) and the left ((B), lower panel) eyes.
An Optical Coherence Tomography-Based Measure as an Independent Estimate of Retinal Function in Retinitis Pigmentosa
  • Article
  • Full-text available

November 2023

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56 Reads

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2 Citations

Background: With the clinical advances in the field of gene therapy, the development of objective measures of visual function of patients with inherited retinal dystrophies (IRDs) is of utmost importance. Here, we propose one such measure. Methods: We retrospectively analyzed data from a cohort of 194 eyes of 97 genetically diagnosed patients with retinitis pigmentosa (RP), the most common IRD, followed at the UPMC Vision Institute. The analyzed data included the reflectivity ratio (RR) of the retinal nerve fiber layer (RNFL) to that of the entire retina, visual acuity (VA) and the thickness of the retinal outer nuclear layer (ONL) and the RNFL. Results: There was a strong positive correlation between the RR and VA. Both VA and the RR were negatively correlated with disease duration; VA, but not the RR, was negatively correlated with age. The RR correlated with the ONL but not with the RNFL thickness or the intraocular pressure. Age, RR, disease duration and ONL thickness were found to be independent predictors of VA by multivariate analysis. Conclusion: The OCT RR could serve as an independent predictor of visual acuity, and by extension of retinal function, in genetically diagnosed RP patients. Such objective measures can be of great value in patient selection for therapeutic trials.

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Challenges in posterior uveitis—tips and tricks for the retina specialist

August 2023

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451 Reads

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5 Citations

Journal of Ophthalmic Inflammation and Infection

Purpose Posterior uveitis is a common chorioretinal pathology affecting all ages worldwide and is a frequent reason for referral to the retina clinic. The spectrum of etiologies for uveitis is very broad and includes infectious and auto-immune diseases. Inflammation can be confined to the eye or may be a part of systemic disease. A useful outline is therefore proposed to aid in the correct diagnosis of these challenging entities. The situation is further complicated by the fact that many neoplastic conditions resemble features of posterior uveitis; they are known as “masqueraders of uveitis”. Here, we summarize different posterior uveitides that present with rare findings, along with masqueraders that can be difficult to distinguish. These conditions pose a diagnostic dilemma resulting in delay in treatment because of diagnostic uncertainty. Methods An extensive literature search was performed on the MEDLINE/PUBMED, EBSCO and Cochrane CENTRAL databases from January 1985 to January 2022 for original studies and reviews of predetermined diagnoses that include posterior uveitic entities, panuveitis and masquerade syndromes. Results We described conditions that can present as mimickers of posterior uveitis (i.e., immune check-points inhibitors and Vogt-Koyanagi-Harada-like uveitis; leukemia and lymphoma associated posterior uveitis), inflammatory conditions that present as mimickers of retinal diseases (i.e., Purtscher-like retinopathy as a presentation of systemic lupus erythematosus; central serous chorioretinopathy masquerading inflammatory exudative retinal detachment), and uveitic conditions with rare and diagnostically challenging etiologies (i.e., paradoxical inflammatory effects of anti-TNF-α; post vaccination uveitis; ocular inflammation after intravitreal injection of antiangiogenic drugs). Conclusion This review of unique posterior uveitis cases highlights the overlapping features of posterior uveitis (paradoxical inflammatory effects of anti -TNF α and uveitis; Purtscher-like retinopathy as a presentation of systemic lupus erythematosus, …) and the nature of retinal conditions (ischemic ocular syndrome, or central retinal vein occlusion, amyloidosis, inherited conditions like retinitis pigmentosa, autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV), etc.…) that may mimic them is represented. Careful review of past uveitis history, current medications and recent vaccinations, detailed examination of signs of past or present inflammation, eventually genetic testing and/ or multimodal retinal imaging (like fluorescein angiography, EDI-OCT, OCT-angiography for lupus Purtscher-like retinopathy evaluation, or ICG for central serous retinopathy, or retinal amyloid angiopathy) may aid in correct diagnosis.


Coagulase-negative staphylococcal endophthalmitis: clinical severity and outcomes based on speciation

June 2023

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34 Reads

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2 Citations

Canadian Journal of Ophthalmology

Objective: To identify characteristics and visual outcomes of coagulase-negative staphylococci (CoNS) endophthalmitis in the era after the Endophthalmitis Vitrectomy Study. Design: Single-centre retrospective analysis. Participants: Forty-two samples from 40 patients with documented CoNS endophthalmitis. Methods: Visual acuity outcomes of patients with CoNS endophthalmitis were assessed in relation to species and type of treatment instituted (e.g., pars plana vitrectomy [PPV] versus tap and injection of intravitreal antibiotics [T&I]). Strains were speciated using Gram and Giemsa staining and were further identified using API Staph and Biolog GEN III microplates. Genetic analysis was performed via polymerase chain reaction. Antibiotic susceptibility was assessed with disk diffusion. Results: Staphylococcus epidermidis was the most prevalent CoNS in our study. Cataract surgery and intravitreal injections were the most common sources for acute CoNS endophthalmitis. Eyes presenting with hand motion or better vision had similar mean final vision after either intravitreal antibiotics or PPV, whereas those with light perception or worse vision at onset had better outcomes after PPV only. Subanalysis showed that patients with S. epidermidis endophthalmitis (n = 39 eyes) had similar visual outcomes with either intravitreal injections or PPV regardless of visual acuity. Hypopyon and vitritis are not always present. Conclusions: Patients with S. epidermidis endophthalmitis may benefit similarly from either early vitrectomy or intravitreal antibiotic injections regardless of visual acuity. This finding complements the management standards set forth by the Endophthalmitis Vitrectomy Study.


Association of Dietary Nitrate and a Mediterranean Diet With Age-Related Macular Degeneration Among US Adults: The Age-Related Eye Disease Study (AREDS) and AREDS2

December 2022

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108 Reads

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11 Citations

Jama Ophthalmology

Importance Low dietary nitrate intake has previously been suggested to be a risk factor for age-related macular degeneration (AMD) progression; however, this finding has not been replicated in other cohorts or adjusted for dietary patterns. Objective To determine whether there is an association between dietary nitrate intake and AMD progression. Design, Setting, and Participants This cohort study analyzed data from the prospective Age-Related Eye Disease Study (AREDS) and AREDS2 randomized clinical trial cohorts and their extended follow-up studies, which were conducted in multicenter outpatient retinal practices. Participants in both trials had non–late AMD in at least 1 eye. Data were analyzed from March 1, 2020, to September 30, 2022. Exposure Dietary nitrate intake. Main Outcomes and Measures Association between dietary nitrate intake and development of late AMD (neovascular AMD [nAMD] or geographic atrophy [GA]) or large drusen. The interactions of dietary patterns, with common at-risk single-nucleotide polymorphisms, were also assessed. Results In the combined AREDS/AREDS2 cohort of 7788 participants (4288 AREDS participants and 3610 AREDS2 participants [110 of whom participated in both studies]), there were 13 511 eligible eyes. The combined cohort comprised 4396 women (56%) and 3392 men (44%), and the combined mean (SD) age was 71.1 (6.6) years. Dietary nitrate intake was associated with a decreased risk of progression to late AMD in the combined AREDS/AREDS2 cohort (hazard ratio [HR], 0.77 [95% CI, 0.69-0.86] for quartile 4 vs quartile 1 of intake) and a decreased risk of GA (HR, 0.71 [95% CI, 0.61-0.83]) and nAMD (HR, 0.85 [95% CI, 0.73-0.99]). In AREDS, increased nitrate intake (quartile 4 vs quartile 1) was associated with a decreased risk of late AMD (HR, 0.77 [95% CI, 0.65-0.91]) and GA (HR, 0.80 [95% CI, 0.65-0.97]) but not nAMD; in AREDS2, there was no association between nitrate intake (quartile 4 vs quartile 1) and late AMD (HR, 0.90 [95% CI, 0.80-1.02]) or nAMD (HR, 0.93 [95% CI, 0.78-1.11]). There was a correlation between Mediterranean dietary patterns and dietary nitrate intake ( r = 0.52, P < .001). Conclusions and Relevance The findings of this cohort study suggest that dietary nitrate intake was associated with lower AMD risk. However, this association disappeared after adjusting for Mediterranean dietary patterns. These results are subject to potential bias and are hypothesis-generating in nature; therefore, they are insufficient to support new clinical recommendations. Previously described associations between dietary nitrate intake and AMD may in fact represent overall dietary patterns. Further research is needed before dietary nitrate intake can be recommended as a therapy for AMD.


Long-term Outcomes of Adding Lutein/Zeaxanthin and ω-3 Fatty Acids to the AREDS Supplements on Age-Related Macular Degeneration Progression: AREDS2 Report 28

June 2022

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407 Reads

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113 Citations

Jama Ophthalmology

Importance: After the Age-Related Eye Disease Study 2 (AREDS2) study, the beta carotene component was replaced by lutein/zeaxanthin for the development of the revised AREDS supplement. However, it is unknown if the increased risk of lung cancer observed in those assigned beta carotene persists beyond the conclusion of the AREDS2 trial and if there is a benefit of adding lutein/zeaxanthin to the original AREDS supplement that can be observed with long-term follow-up. Objective: To assess 10-year risk of developing lung cancer and late age-related macular degeneration (AMD). Design, setting, and participants: This was a multicenter epidemiologic follow-up study of the AREDS2 clinical trial, conducted from December 1, 2012, to December 31, 2018. Included in the analysis were participants with bilateral or unilateral intermediate AMD for an additional 5 years after clinical trial. Eyes/participants were censored at the time of late AMD development, death, or loss to follow-up. Data were analyzed from November 2019 to March 2022. Interventions: During the clinical trial, participants were randomly assigned primarily to lutein/zeaxanthin and/or ω-3 fatty acids or placebo and secondarily to no beta carotene vs beta carotene and low vs high doses of zinc. In the epidemiologic follow-up study, all participants received AREDS2 supplements with lutein/zeaxanthin, vitamins C and E, and zinc plus copper. Outcomes were assessed at 6-month telephone calls. Analyses of AMD progression and lung cancer development were conducted using proportional hazards regression and logistic regression, respectively. Main outcomes and measures: Self-reported lung cancer and late AMD validated with medical records. Results: This study included 3882 participants (mean [SD] baseline age, 72.0 [7.7] years; 2240 women [57.7%]) and 6351 eyes. At 10 years, the odds ratio (OR) of having lung cancer was 1.82 (95% CI, 1.06-3.12; P = .02) for those randomly assigned to beta carotene and 1.15 (95% CI, 0.79-1.66; P = .46) for lutein/zeaxanthin. The hazard ratio (HR) for progression to late AMD comparing lutein/zeaxanthin with no lutein/zeaxanthin was 0.91 (95% CI, 0.84-0.99; P = .02) and comparing ω-3 fatty acids with no ω-3 fatty acids was 1.01 (95% CI, 0.93-1.09; P = .91). When the lutein/zeaxanthin main effects analysis was restricted to those randomly assigned to beta carotene, the HR was 0.80 (95% CI, 0.68-0.92; P = .002). A direct analysis of lutein/zeaxanthin vs beta carotene showed the HR for late AMD was 0.85 (95% CI, 0.73-0.98; P = .02). The HR for low vs high zinc was 1.04 (95% CI, 0.94-1.14; P = .49), and the HR for no beta carotene vs beta carotene was 1.04 (95% CI, 0.94-1.15; P = .48). Conclusions and relevance: Results of this long-term epidemiologic follow-up study of the AREDS2 cohort suggest that lutein/zeaxanthin was an appropriate replacement for beta carotene in AREDS2 supplements. Beta carotene usage nearly doubled the risk of lung cancer, whereas there was no statistically significant increased risk with lutein/zeaxanthin. When compared with beta carotene, lutein/zeaxanthin had a potential beneficial association with late AMD progression.



Lidocaine Gel Interferes With the Antibacterial Activity of Povidone-Iodine

July 2021

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14 Reads

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2 Citations

Ophthalmic Surgery, Lasers and Imaging Retina

Background and objective: Retina specialists use lidocaine gel as a topical anesthetic. We determined the antibacterial interaction between povidone-iodine (PI) and lidocaine gel using corneoscleral tissue as a solid phase medium. Materials and methods: Five pieces of corneoscleral tissue in five trials were inoculated with 1.000 colony-forming units of bacteria isolated from endophthalmitis. Inoculated corneal tissue were overlaid with nothing (control), lidocaine gel, 5% PI, lidocaine gel over 5% PI, and 5% PI over lidocaine gel for 5 minutes prior to placement in growth liquid medium at 37°C. Growth was monitored for 48 hours. Results: Application of lidocaine gel prior to 5% PI application provided for the growth of the five bacterial isolates, whereas 5% PI prior to lidocaine gel prevented growth. Conclusion: Using corneoscleral tissue, PI and lidocaine gel appear to have an antagonistic interaction when lidocaine gel is applied initially prior to 5% PI, preventing bactericidal activity of PI. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:S13-S16.].


Biomechanics of Scleral Buckling and Effects on Eye Geometry

May 2021

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26 Reads

Scleral buckling is a method of reattaching the neurosensory retina to the retinal pigment epithelium when retinal detachment occurs. While the buckle procedure has high success rates in terms of reattaching the retina, the forces created by encircling and segmental buckles can alter the biomechanical properties of the eye and many of its structures, including axial length, corneal power, astigmatism, corneal hysteresis, corneal resistance factor, anterior chamber depth, ocular volume, ocular rigidity, and ocular blood flow. This chapter delves into the biomechanical changes induced by scleral buckling.



Citations (72)


... Numerous investigations have employed optical coherence tomography (OCT) to assess the overall retinal structure in RP patients, and the latest advancements in high-resolution OCT technology facilitate the observation of finer retinal details. With the introduction of spectral-domain SD-OCT, it has become feasible to obtain structural information regarding retinal anatomical irregularities in individuals with RP. 10 Consequently, given the progress in technology that allows for the visualization of more intricate retinal structures, we undertook this study to assess the prevalence of macular abnormalities identified by OCT in patients diagnosed with retinitis pigmentosa. Objective: To assess the frequency of macular abnormalities identified through OCT in individuals with retinitis pigmentosa. ...

Reference:

Macular abnormalities in patients with Retinitis Pigmentosa.
An Optical Coherence Tomography-Based Measure as an Independent Estimate of Retinal Function in Retinitis Pigmentosa

... Further analysis of infectious uveitis reveals that infections in uveitis can be more confined to the eye region (ocular toxoplasmosis) or with more generalized infections (syphilis, tuberculosis, or Lyme disease) or systemic infections. The summarized data of previously reported worldwide studies also indicated that uveitis is more commonly associated with systemic infections (58%) than local or non-systemic infections (29%) [40][41][42][43]. But, further research is needed to confirm these estimates. ...

Challenges in posterior uveitis—tips and tricks for the retina specialist

Journal of Ophthalmic Inflammation and Infection

... [1][2][3] Although genetic factors are estimated to contribute to 46% to 71% of AMD cases, 4 lifestyle factors like smoking and dietary habits have also been identified as notable risk factors for AMD development. [5][6][7] Exploring the modifiable factors for AMD is important because it may offer new intervention strategies to delay or prevent the onset of the disease and ultimately reduce its burden on public health. 8,9 Although the pathogenesis of AMD is not fully understood, several studies have indicated that AMD shares a vascular disorder nature similar to atherosclerosis, which is a major cause of cardiovascular disease (CVD). ...

Association of Dietary Nitrate and a Mediterranean Diet With Age-Related Macular Degeneration Among US Adults: The Age-Related Eye Disease Study (AREDS) and AREDS2
  • Citing Article
  • December 2022

Jama Ophthalmology

... However, a recent post-hoc analysis in 2025 evaluated the efficacy of AREDS and AREDS2 supplements in halting GA in terms of areabased progression (i.e., change in GA area over time) and proximity-based progression (i.e., change in GA proximity to macular centre-point over time). 14 The AREDS study showed the rate of GA progression to the central macula was significantly slower in those randomised to antioxidants versus no antioxidants at 50.7 μm/year and 72.9 μm/ year respectively (P = 0.012). This treatment effect was similarly demonstrated in the AREDS2 study where GA progression toward the central macula was significantly slower in eyes randomised to lutein/zeaxanthin versus no lutein/zeaxanthin, at 84.5 μm/year and 105.3 μm/year respectively (P = 0.017). ...

Long-term Outcomes of Adding Lutein/Zeaxanthin and ω-3 Fatty Acids to the AREDS Supplements on Age-Related Macular Degeneration Progression: AREDS2 Report 28
  • Citing Article
  • June 2022

Jama Ophthalmology

... However, it is important to note that the antiseptic must be applied separately prior to LG to achieve this effect. In agreement with our results, other studies have reported that both PI and CHX lose effectiveness if administered after LG [3,6,10,27,28,36]. This suggests that LG may act as a physical barrier, preventing the antiseptic from penetrating and exerting an effect, or that a non-synergistic interaction occurs between the two chemicals. ...

Lidocaine Gel Interferes With the Antibacterial Activity of Povidone-Iodine
  • Citing Article
  • July 2021

Ophthalmic Surgery, Lasers and Imaging Retina

... However, despite its initial success, the laser failed to improve BCVA or reduce Ann Eye Sci 2021 | https://dx.doi.org/10.21037/aes-21-46 choroidal neovascularization for prophylactic treatment of AMD during a multicenter, randomized, clinical trial (124,125). Since this study, the company has researched ways to improve and optimize their design. While IRIDEX has primarily created lasers for retinal treatment, the company has also introduced their micropulse technology for glaucoma applications (113). ...

Prophylactic Treatment of Age-Related Macular Degeneration Report Number 2: 810-Nanometer Laser to Eyes With Drusen: Bilaterally Eligible Patients
  • Citing Article
  • October 2009

Ophthalmic Surgery Lasers and Imaging

... A meta-analysis reported an incidence of about one endophthalmitis case for every 1779 injections of anti-VEGF (0.056%). 4 The most common pathogens identified in culture are staphylococcus and streptococcus species [4]. However, several previous reports described quiescence of disease activity in neovascular age related macular degeneration (NVAND) patients, post-endophthalmitis, [5][6][7][8][9][10][11][12] and one case with myopic choroidal neovascularization (CNV) [11]. The exact reason for this quiescence is unknown. ...

RELATIVE QUIESCENCE OF EXUDATIVE AGE-RELATED MACULAR DEGENERATION AFTER RESOLUTION OF POSTINJECTION ENDOPHTHALMITIS
  • Citing Article
  • November 2019

Retina

... Previous SLT studies have raised a concern that SLTs might increase the risk of neovascularization for eyes with large drusens (Friberg et al., 2006). Hence, we investigated the treatment-induced changes in the production of VEGF, which regulates the proliferation and density of endothelial cells in the choriocapillaris, extracellular space, and around the Bruch's membrane. ...

Prophylactic Treatment of Age-Related Macular Degeneration Report Number 1: 810-Nanometer Laser to Eyes with Drusen. Unilaterally Eligible Patients
  • Citing Article
  • May 2006

Ophthalmology

... As in Asian patients, the presence of diffuse and/or banded FAF patterns, compared with focal FAF patterns or minimal or absent FAF abnormalities, was associated with a significantly higher GA progression rate in White patients (there were insufficient occurrences of the patchy GA subphenotype in this study to draw conclusions) [60]. Research has shown that there are several other factors associated with growth rate [37,58,[83][84][85][86]. The presence of multifocal lesions rather than a unifocal lesion, foveal involvement, progression towards the periphery rather than toward the foveal center, and intermediate baseline lesion size have been shown to be associated with faster GA progression [37,58,[83][84][85][86] (Fig. 4). ...

Progression of Geographic Atrophy in Age-related Macular Degeneration
  • Citing Article
  • July 2018

Ophthalmology

... The mean visual acuity was 0.204 logMAR in the ERM group and 0.079 logMAR in the control group. The mean intraocular pressure was 14.31 ± 2.82 (range 11-21) mmHg in the ERM group and 14.52 ± 2.43 (range [11][12][13][14][15][16][17][18][19] mmHg in the control group. ...

Morphological and Angiographic Peripheral Retinal Changes in Patients with Age-Related Macular Degeneration
  • Citing Article
  • September 2017

Ophthalmology Retina