Mania as a Rare Adverse Event Secondary to Steroid Eye Drops.

Since glucocorticoids (GCs) were introduced for the treatment of various diseases, they have been linked with the development of psychiatric adverse effects such as mania, depression, and psychosis. These behavioral or psychiatric adverse events usually appear within a few days after commencing GCs and are possibly to reverse with drug withdrawal. We present a rare case of a 75-year-old woman who developed mania during treatment with GC eye drops following cataract surgery. Management consisted of discontinuing prednisolone and administering olanzapine, which resulted in full recovery in a week. Olanzapine was then discontinued, and a diagnosis of steroid-induced mania was concluded for this case.

Impact of surgical case order on epiretinal membrane peeling surgery.

OBJECTIVE: To determine whether surgical warm-up affects epiretinal membrane (ERM) peeling complication rates and surgical case times. SETTING: Jewish General Hospital, Montreal, QC, Canada. DESIGN: Retrospective case-control study. METHODS: We assessed consecutive patients who underwent pars plana vitrectomy for ERM peel (macular pucker) by one surgeon at the Jewish General Hospital from January 2006 until March 2016. Cases evaluated were sequential ERM peels performed as the first 2 surgeries of the day. The first case of the day was considered the "warm-up" and the second case was the "post-warm-up." Baseline demographics, pre-operative characteristics, perioperative and postoperative best-corrected visual acuity (BCVA) at 2 months and 6 months, as well as postoperative complications are described. Results were analyzed using the χ2 test, t test, and Fischer's exact test. Regression models were used to identify any predictors of postoperative BCVA. RESULTS: The study reviewed 108 patients. The warm-up group was compared with the post-warm-up group, and there was no significant difference between the mean pre-operative BCVA and the post-operative BCVA at 2 and 6 months. ERM peeling surgery complication rates were not statistically different between the warm-up cases and the post-warm-up cases. There was a tendency for performing complex surgeries that needed phaco procedures in post-warm-up cases (13% vs 2%, p = 0.03). Analysis of simple ERM peeling procedures (with no concomitant phaco procedures) showed no statistically significant tendencies for any of the groups to go beyond the 60 minutes allocated for the surgery (25.4% vs 20.0%, p = 0.27). CONCLUSION: Warming-up does not influence the rate of postoperative complications or the postoperative BCVA in patients undergoing ERM peels. The strongest predictor of post-operative BCVA was pre-operative BCVA.

Determining the effect of low-dose isotretinoin on proliferative vitreoretinopathy: the DELIVER trial.

PURPOSE: To examine the effect of low-dose, oral isotretinoin in lowering the risk of proliferative vitreoretinopathy (PVR) following rhegmatogenous retinal detachment (RRD) repair. METHODS: Prospective, open label, dual-cohort study with pathology-matched historical controls. The prospective experimental arms included two cohorts, composed of 51 eyes with recurrent PVR-related RRD and 58 eyes with primary RRD associated with high-risk features for developing PVR. Eyes in the experimental arms received 20 mg of isotretinoin by mouth once daily for 12 weeks starting the day after surgical repair. The primary outcome measure was single surgery anatomical success rate at 3 months following the study surgery. RESULTS: The single surgery anatomic success rate was 78.4% versus 70.0% (p=0.358) in eyes with recurrent PVR-related retinal detachment exposed to isotretinoin versus historical controls, respectively. In eyes with RRD at high risk for developing PVR, the single surgery success rate was 84.5% versus 61.1% (p=0.005) for eyes exposed to isotretinoin versus historical controls, respectively. For eyes enrolled in the experimental arms, the most common isotretinoin-related side effects were dry skin/mucus membranes in 106 patients (97.2%), abnormal sleep/dreams in 4 patients (3.7%) and fatigue in 3 patients (2.8%). CONCLUSION: The management and prevention of PVR is challenging and complex. At the dose and duration given in this study, oral istotretinoin may reduce the risk of PVR-associated recurrent retinal detachment in eyes with primary RRD at high risk of developing PVR.

Comparison of different settings for yellow subthreshold laser treatment in diabetic macular edema.

BACKGROUND: To assess the safety and efficacy of two subthreshold parameters (5 and 15% duty cycle (DC)) compared to standard ETDRS (early treatment of diabetic retinopathy study) continuous wave (CW) laser. METHODS: In this prospective randomized study, 30 eyes from 20 patients with non-center involving macular edema were randomized into 3 different groups: 5% DC, 15% DC and CW navigated modified ETDRS laser treatment. Titration in subthreshold groups was performed with 30% of the threshold power, decided with microsecond pulses. CW laser was titrated to a barely visible burn. All patients underwent microperimetry, thickness measurements and visual acuity examinations at baseline, 6 weeks and 12 weeks post treatment. RESULTS: At three months follow up, retinal sensitivity was significantly reduced in the CW group by - 2.2 dB whereas in both subthreshold groups, retinal sensitivity increased by 2.4 dB for 5% and 1.9 dB for 15% DC with no significant difference. Retinal volume (mm3) decreased in both subthreshold groups by 0.08 ± 0.3 and 0.12 ± 0.11 in 5 and 15% DC group respectively. Whereas the CW group showed volume increase of 0.55 ± 0.92 (p = 0.02 and 0.01 for 5 and 15% DC groups). Visual acuity remained stable in all 3 groups (- 0.7 letter in 5% DC; 2.11 letters in 15% DC and 0.88 in CW with no significant difference). CONCLUSION: Subthreshold microsecond laser was shown to be safe and effective with both 5 and 15% DC as compared to conventional photocoagulation with ETDRS parameters. The 15% DC setting trended to achieve better anatomical, visual and functional outcomes. TRIAL REGISTRATION: Retrospectively registered ( NCT03571659 , 06/26/2018).

OUTCOMES OF ANTI-VEGF THERAPY IN CHOROIDAL NEOVASCULARIZATION AFTER MACULAR SURGERY.

PURPOSE: To report treatment outcomes of anti-vascular endothelial growth factor (VEGF) therapy in choroidal neovascularization (CNV) presenting after macular surgery. METHODS: Retrospective analysis of 7 eyes of 7 patients, who were diagnosed to have CNV after macular surgery and were treated with anti-vascular endothelial growth factor therapy. Collected data included demographic details; history of present illness; surgical procedure; and clinical examination including visual acuity at presentation and follow-up with imaging and management. Main outcome measures were resolution of CNV activity at the last follow-up. Secondary outcomes included change in visual acuity at final follow-up from baseline, number of injections, treatment free interval, and adverse events. RESULTS: Seven eyes of 7 patients (2 females and 5 males), which underwent macular surgery (4 macular hole repairs and 3 epiretinal membrane (ERM) removal), were included in this study. Two eyes had drusen at the time of surgery; however, five eyes had no preexisting conditions. Mean interval between surgery and CNV development was 21.07 ± 38.55 months (range, 2 months-9 years). All patients had undergone intravitreal anti-vascular endothelial growth factor injections (range, 2-15; mean number: 5.85) with one eye requiring additional photodynamic therapy (PDT) and focal laser. Visual acuity was unchanged with inactive CNV at the last visit in all eyes after anti-vascular endothelial growth factor therapy. The mean follow-up duration after the development of CNV was 35.5 months (range, 6.5 months-8 years). CONCLUSION: Choroidal neovascularization occurring after otherwise successful macular surgery is uncommon with unknown predisposing factors. This entity appears to have poor visual outcome with currently available anti-vascular endothelial growth factor therapy.

Segmentation errors in macular ganglion cell analysis as determined by optical coherence tomography in eyes with macular pathology.

BACKGROUND: To evaluate artifacts in macular ganglion cell inner plexiform layer (GCIPL) thickness measurement in eyes with retinal pathology using spectral-domain optical coherence tomography (SD OCT). METHODS: Retrospective analysis of color-coded maps, infrared images and 128 horizontal B-scans (acquired in the macular ganglion cell inner plexiform layer scans), using the Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA). The study population included 105 eyes with various macular conditions compared to 30 eyes of 30 age-matched healthy volunteers. The overall frequency of image artifacts and the relative frequency of artifacts were stratified by macular disease. RESULTS: Scan errors and artifacts were found in 55.1% of the 13,440 B-scans in eyes with macular pathology and 26.8% of the 3840 scans in normal eyes. Segmentation errors were the most common scan error in both groups, with more common involvement of both segmentation borders in diseased eyes and anterior segmentation border in normal eyes. CONCLUSION: Segmentation errors and artifacts in SD OCT GCA are common in conditions involving the macula. These findings should be considered when assessing macular GCIPL thickness and careful assessment of scans is suggested.

Choroidal vascular analysis in myopic eyes: evidence of foveal medium vessel layer thinning.

PURPOSE: To analyse morphologic features of the choroid in Non-pathological myopic eyes using spectral-domain (SD) optical coherence tomography (OCT). METHODS: Retrospective analysis of enhanced depth SD-OCT images of Non-pathological myopic eyes in comparison with age-matched healthy controls was performed. Choroidal thickness (CT) and large choroidal vessel thickness (LCVT) were measured at the fovea, 750 µm nasally from fovea (N750) and 750 µm temporally (T750) from fovea. Medium choroidal vessel thickness (MCVT) was calculated by subtracting LCVT from CT. Choriocapillaris was encompassed by MCVT, given its reduced thickness. Linear regression analysis evaluated the relationship between age and axial with CT, LCVT and MCVT. RESULTS: The study group comprised 42 eyes of 31 patients (mean age 46.13 ± 15.63; 15 females). Control group included 57 eyes of 34 patients (mean age of 42.3 ± 15.29; 24 females). Mean axial length in myopic eyes and control group was 26.57 ± 1.27 and 23.59 ± 0.99 mm respectively. Myopic eyes showed significant thinning of MCVT and CT at all locations (p < 0.0001) compared to controls, unlike LCVT (p > 0.05). With each decade, thinning of up to 37 µm in CT was noted along with thinning of LCVT (up to 22.6 µm) and MCVT (up to 25 µm). Each mm increase in axial length caused 38.2 µm thinning of choroid along with LCVT (<10 µm), however, MCVT showed more notable thinning (>30 µm). CONCLUSION: Significant thinning of MCVT was noted in non-pathological myopic eyes in comparison to healthy subjects. It appears that MCVT has stronger relationship with age and axial length.

Subfoveal Choroidal Vascularity in Myopia: Evidence From Spectral-Domain Optical Coherence Tomography.

BACKGROUND AND OBJECTIVE: To evaluate subfoveal choroidal vascularity in eyes with myopia in comparison to age-matched healthy subjects. PATIENTS AND METHODS: Retrospective analysis of single foveal enhanced depth imaging optical coherence tomography (EDI-OCT) scans of 30 eyes with myopia (axial length greater than 25 mm). Subfoveal choroidal vascularity was evaluated by calculating vessel-area-to-stromal-area ratio using a previously validated automated algorithm. RESULTS: The subfoveal stromal area was significantly smaller in myopes (0.95 mm3 ± 0.22 mm3) compared to controls (1.33 mm3 ± 0.23 mm3; P < .0001). However, there was no significant difference in vascular area or in vessel-area-to-stroma-area ratio between the groups (P = .15 and P = .16, respectively). Subfoveal choroidal vascularity percentage was also not significantly different between the two groups (P = .07). CONCLUSION: Subfoveal choroidal thinning in myopia is primarily associated with a reduction in choroidal stroma, not vascular components. This needs further exploration and has potential clinical applications. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:202-207.].

Simultaneous central retinal artery occlusion and optic nerve vasculitis in Crohn disease.

PURPOSE: To describe a case of Crohn disease presenting as occlusive vasculitis resulting in a central retinal artery occlusion (CRAO) in one eye and transient ischemic optic neuropathy in the fellow eye. OBSERVATIONS: An 18-year-old patient recently diagnosed with biopsy-proven Crohn disease presented with CRAO OD after a previous episode of transient visual loss OS. Extensive workup was negative for other autoimmune or infectious etiologies. The patient was started on intravenous methylprednisolone for 72 h followed by maintenance dose of azathioprine and oral prednisone. Signs of inflammation resolved gradually with some improvement of visual acuity despite developing optic atrophy. CONCLUSIONS AND IMPORTANCE: To our knowledge, this is the first case of unilateral CRAO and bilateral optic nerve occlusive vasculitis in Crohn disease, which should be considered as an etiology of retinal vascular occlusive disorders especially in young patients. It is important for ophthalmologists to be aware of the ophthalmic risks associated with Crohn disease as aggressive treatment with systemic steroids and immunosuppressive agents is often needed.

In Vivo Evidence of Inner Retinal Neurodegeneration in Retinitis Pigmentosa Using Spectral-Domain Optical Coherence Tomography.

BACKGROUND AND OBJECTIVE: To investigate the topographic changes in macular ganglion cell inner plexiform layer (GCIPL) thickness in eyes with retinitis pigmentosa (RP). PATIENTS AND METHODS: Forty-five eyes of 25 subjects with RP who underwent spectral-domain optical coherence tomography (SD-OCT) using the Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA) were analyzed retrospectively. A control group of 67 eyes of 48 age-matched healthy volunteers was also included for comparison. Average, minimum, and sectoral macular GCIPL, as well as retinal nerve fiber layer (RNFL) and outer retinal (OR) thicknesses, were collected and compared between RP and control groups. RESULTS: The average and sectoral macular GCIPL thicknesses were significantly reduced in RP eyes compared with controls (P < .0001). Average macular RNFL thickness was reduced in RP eyes compared with controls (P < .054). CONCLUSIONS: In eyes with RP, display reduced GCIPL, RNFL, and OR thickness. The identification of alteration in RNFL, OR, and GCIPL thickness may be useful for future therapeutic implications. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:828-835.].

Prevalence and Distribution of Segmentation Errors in Macular Ganglion Cell Analysis of Healthy Eyes Using Cirrus HD-OCT.

PURPOSE: To determine the frequency of different types of spectral domain optical coherence tomography (SD-OCT) scan artifacts and errors in ganglion cell algorithm (GCA) in healthy eyes. METHODS: Infrared image, color-coded map and each of the 128 horizontal b-scans acquired in the macular ganglion cell-inner plexiform layer scans using the Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA) macular cube 512 × 128 protocol in 30 healthy normal eyes were evaluated. The frequency and pattern of each artifact was determined. Deviation of the segmentation line was classified into mild (less than 10 microns), moderate (10-50 microns) and severe (more than 50 microns). Each deviation, if present, was noted as upward or downward deviation. Each artifact was further described as per location on the scan and zones in the total scan area. RESULTS: A total of 1029 (26.8%) out of total 3840 scans had scan errors. The most common scan error was segmentation error (100%), followed by degraded images (6.70%), blink artifacts (0.09%) and out of register artifacts (3.3%). Misidentification of the inner retinal layers was most frequent (62%). Upward Deviation of the segmentation line (47.91%) and severe deviation (40.3%) were more often noted. Artifacts were mostly located in the central scan area (16.8%). The average number of scans with artifacts per eye was 34.3% and was not related to signal strength on Spearman correlation (p = 0.36). CONCLUSIONS: This study reveals that image artifacts and scan errors in SD-OCT GCA analysis are common and frequently involve segmentation errors. These errors may affect inner retinal thickness measurements in a clinically significant manner. Careful review of scans for artifacts is important when using this feature of SD-OCT device.

In vivo evaluation of retinal ganglion cells degeneration in eyes with branch retinal vein occlusion.

PURPOSE: To analyse the topographic changes in retinal ganglion cells (RGCs) in eyes with unilateral naive branch retinal vein occlusion (BRVO) in comparison to normal fellow eyes and to healthy control eyes. METHODS: We performed a retrospective analysis of 66 eyes (33 subjects) with naive unilateral BRVO who underwent spectral-domain optical coherence tomography using Cirrus HD-OCT. We also included 67 eyes of 48 age-matched healthy volunteers as control group. Average, minimum and sectoral macular ganglion cell-inner plexiform layer (GCIPL) thickness, macular retinal nerve fibre layer (RNFL) thickness and outer retinal thickness were collected. Comparison of the GCIPL, RNFL and outer retinal thicknesses among study eyes, normal fellow eyes and control groups was performed. RESULTS: The average and minimum macular GCIPL thicknesses were constantly and diffusely reduced in BRVO compared with normal fellow eyes and healthy controls (p<0.001 for each GCIPL sector). The average macular RNFL thickness was reduced in BRVO eyes compared with normal fellow eyes (p=0.01) and tended to be lower than controls (p=0.07). The minimum RNFL thickness in eyes with BRVO was significantly reduced when compared with fellow eyes (p<0.001) and control eyes (p<0.001). The average outer retina thickness was thicker in BRVO eyes compared with both fellow eyes (p<0.001) and controls (p<0.001). CONCLUSIONS: A significant reduction of the macular GCIPL and RNFL thicknesses was observed in eyes with BRVO. This finding is suggestive of RGCs degeneration; the neuroprotective effect of current therapeutic options might be an important consideration when evaluating treatment strategies and prognosticating visual outcome in BRVO eyes.

Pars plana vitrectomy and scleral buckle versus pars plana vitrectomy alone for patients with rhegmatogenous retinal detachment at high risk for proliferative vitreoretinopathy.

PURPOSE: To compare using pars plana vitrectomy (PPV) combined with a scleral buckle versus primary vitrectomy alone in patients with rhegmatogenous retinal detachment at high risk for postoperative proliferative vitreoretinopathy (PVR). METHODS: Six hundred and seventy-eight patients were identified from billing data as having rhegmatogenous retinal detachment between April 1, 2010 and August 1, 2012. Patients were considered at high risk for PVR if they presented with retinal detachment in 2 or more quadrants, retinal tears >1 clock hour, preoperative PVR, or vitreous hemorrhage. RESULTS: Of the 678 patients with rhegmatogenous retinal detachment, 65 were identified as high risk for PVR. Thirty-six patients were treated with simultaneous PPV-scleral buckle and 29 patients were treated with PPV alone, with an overall success rate of 63.1%. The use of PPV-scleral buckle was associated with significantly higher single surgery anatomical success compared with patients treated with PPV alone (odds ratio, 3.24; 95% confidence interval, 1.12-9.17; P = 0.029). Visual acuity at 3 months postprocedure or final follow-up was no different between the treatment groups. Overall, 23.1% of patients developed postoperative PVR with no difference between surgical approaches. CONCLUSION: For patients at high risk for PVR, PPV-scleral buckle was associated with significantly higher rates of anatomical success compared with PPV alone.

Intravitreal triamcinolone acetonide injection for macular edema due to central retinal vein occlusion persisting despite multiple intravitreal bevacizumab injections.

PURPOSE: To evaluate the response to intravitreal triamcinolone acetonide for macular edema persisting or recurring despite multiple intravitreal bevacizumab (IVB) treatments for central retinal vein occlusion (CRVO). METHODS: Retrospective interventional case series of 21 eyes with CRVO from 21 patients who were diagnosed with persistent or recurrent macular edema secondary to CRVO and treated with 0.1mL (4mg) intravitreal triamcinolone acetonide (IVTA) after initial treatment with 3 or more IVB injections. Anatomic and visual responses were the study primary outcomes. RESULTS: Mean logarithm of the minimum angle of resolution visual acuity was 1.19 (20/316) immediately before IVTA injection, and improved to 1.04 (20/219) 1 month after IVTA administration (P=0.003). The mean central macular thickness on optical coherence tomography decreased from 533.4 µm immediately before IVTA to 327.9 µm after IVTA injection (P<0.001). No cases of endophthalmitis, retinal detachment, or neovascularization were noted. CONCLUSIONS: Intravitreal triamcinolone acetonide appears to improve vision and reduce persistent or recurrent macular edema secondary to CRVO despite multiple bevacizumab injections.

Neovascular events in eyes with central retinal vein occlusion undergoing serial bevacizumab or ranibizumab intravitreal injections: a retrospective review.

PURPOSE: To characterize the onset and type of neovascular events in eyes with central retinal vein occlusion (CRVO) undergoing serial anti-VEGF therapy. METHODS: Consecutive eyes undergoing serial intravitreal bevacizumab or ranibizumab injections for treatment of CME secondary to CRVO were identified. Pertinent data was retrospectively collected and included type and onset of the neovascular event, and the treatment free interval from last injection until the neovascular event. Kaplan-Meier life table analysis was performed to determine the differential effects of baseline perfusion status, early initiation of anti-VEGF treatment (within 3 months of CRVO onset) versus later treatment, and continuous (1-month±2 weeks) versus discontinuous treatment interval (>1.5 months) on time until neovascular event. RESULTS: Of 31 eligible eyes, 12 (39%) and 19 (61%) presented with perfused and ischemic CRVO, respectively. The mean duration from CRVO until the onset of any neovascular event was 17.0±10.3 months. The mean treatment-free interval prior to any neovascular event was 6.2±7.3 months. On average, 5.3±3.2 anti-VEGF injections were given prior to any neovascular event. Neovascularization of the iris or angle occurred in 18 eyes (58%), vitreous hemorrhage associated with neovascularization was observed in 9 eyes (29%) and neovascularization of the disc developed in 5 eyes (16%). Neovascular events showed a trend towards occurring later in eyes with perfused CRVO at baseline (log rank test, P=0.07). CONCLUSION: Neovascular events occur in eyes with CRVO undergoing serial anti-VEGF therapy, and these events may be delayed compared to the natural history of CRVO-associated neovascularization. Iris neovascularization occurred most frequently.

Segmental reproducibility of retinal blood flow velocity measurements using retinal function imager.

BACKGROUND: To evaluate the reproducibility of blood flow velocity measurements of individual retinal blood vessel segments using retinal function imager (RFI). METHODS: Eighteen eyes of 15 healthy subjects were enrolled prospectively at three centers. All subjects underwent RFI imaging in two separate sessions 15 min apart by a single experienced photographer at each center. An average of five to seven serial RFI images were obtained. All images were transferred electronically to one center, and were analyzed by a single observer. Multiple blood vessel segments (each shorter than 100 µm) were co-localized on first and second session images taken at different times of the same fundus using built-in software. Velocities of corresponding segments were determined, and then the inter-session reproducibility of flow velocity was assessed by the concordance correlation co-efficient (CCC), coefficient of reproducibility (CR), and coefficient of variance (CV). RESULTS: Inter-session CCC for flow velocity was 0.97 (95% confidence interval (CI), 0.966 to 0.9797). The CR was 1.49 mm/sec (95% CI, 1.39 to 1.59 mm/sec), and CV was 10.9%. The average arterial blood flow velocity was 3.16 mm/sec, and average venous blood flow velocity was 3.15 mm/sec. The CR for arterial and venous blood flow velocity was 1.61 mm/sec and 1.27 mm/sec respectively. CONCLUSION: RFI provides reproducible measurements for retinal blood flow velocity for individual blood vessel segments, with 10.9% variability.

Serous macular detachment in Waldenström macroglobulinemia: a report of four cases.

PURPOSE: To describe a series of 4 patients with Waldenström macroglobulinemia and serous macular detachment, and propose a mechanism for development of subretinal fluid based on optical coherence tomography (OCT) findings. DESIGN: Retrospective observational case series. METHODS: The records of patients with Waldenström macroglobulinemia and OCT documentation of serous macular detachment at Wills Eye Institute were reviewed. Data collection included clinical examination, as well as findings on fluorescein angiography (FA) and OCT. RESULTS: Four patients (8 eyes) with Waldenström macroglobulinemia and serous retinal detachment were identified. All eyes had varying degrees of venous stasis retinopathy and intraretinal edema overlying the macular detachment. Three patients had no FA leakage, while 1 patient had macular leakage in a petaloid pattern. Focal outer retinal defects within the detached retina were seen in 4 eyes on OCT imaging. In one eye, development of cystoid macular edema was observed before the outer retinal defect and serous macular detachment. All patients with serous macular detachment had some degree of outer retinal disruption. CONCLUSION: Discontinuity of the outer retina within the macular detachment may enable immunoglobulins along with accumulated intraretinal fluid to flow into the subretinal space, creating a serous retinal detachment. Even with systemic treatment of the underlying Waldenström macroglobulinemia, the visual prognosis was guarded.

Comparative analysis of the retinal microvasculature visualized with fluorescein angiography and the retinal function imager.

PURPOSE: To assess the visualization of the retinal microvasculature with intravenous fluorescein angiography (IVFA) compared to the Retinal Function Imager (RFI). DESIGN: Multicenter, retrospective, observational case series. METHODS: Seven normal eyes and 26 eyes with various ocular diseases were imaged with both IVFA and the RFI. The ability to assess vessel loops, vertical collateral vessels, the size of the foveal avascular zone (FAZ), and degree of vessel branching were compared between IVFA and RFI images. RESULTS: The RFI visualized a greater number of vessel loops (1.3 vs 0.4 per eye) and vertical collateral vessels (4.42 vs 0.97 per eye) than IVFA. On average, higher order of vessel branching was seen with the RFI compared to IVFA (5.2 vs 4.6). The foveal avascular zone (FAZ) was more clearly delineated using the RFI and was significantly smaller when measured on RFI (0.35 vs 0.75 mm(2)). CONCLUSIONS: RFI, a noninvasive retinal imaging instrument, revealed vessel loops, vertical collateral vessels, the area of the FAZ, and order of vessel branching in greater detail than IVFA. This instrument may be helpful in understanding dynamic retinal vascular changes in a number of common ocular diseases, as well as in normal eyes.