Canaloplasty and trabeculotomy with the OMNI® surgical system in OAG with prior trabecular microbypass stenting.

PURPOSE: Evaluate effectiveness and safety outcomes for patients treated with canaloplasty and trabeculotomy previously treated with a trabecular microbypass stent (TBS). METHODS: Retrospective, multicenter, IRB approved study. Patients treated with TBS (iStent/iStent inject, Glaukos) and subsequently with OMNI surgical system (OSS) (Sight Sciences). From 5 practices in 5 US states. Open-angle glaucoma (OAG), minimum 3 months follow-up after OSS surgery, Pre-OSS IOP ≥ 17 mmHg on ≥ 1 medication. No glaucoma procedures between TBS and OSS. ENDPOINTS: proportion with ≥ 20% reduction in IOP, IOP between 6 and 18 mmHg, mean IOP, change in IOP, mean number of medications. Adverse events and secondary surgical interventions (SSI). Mann-Whitney rank sum test compared pre-OSS IOP and medications with follow-up. RESULTS: Twenty seven patients. Average age (SD) 72.2 (10.8), 22/27 primary OAG (82%), mean MD - 6.2 (7.0) dB. Mean IOP before OSS 22.3 (4.3) mmHg on 2.2 (1.3) medications. At last follow-up (mean 11 months) IOP was 17.2 mmHg on 1.8 medications, - 5.1 mmHg (- 23%, p < .001), - 0.4 meds (- 18%, p = .193); ≥ 20% IOP reduction (41%), IOP ≤ 18 (56%). Adverse events were non-serious. Hyphema > 1 mm (3, 11%), BCVA decrease (4, 15%), IOP spike (2, 7%). SSI (4, 15%) had higher pre-OSS IOP (23.4 mmHg) and worse MD (- 9.6 dB). CONCLUSION: Patients uncontrolled by medication and a prior TBS would once have been candidates for trabeculectomy and tube shunts. OSS offered a minimally invasive option that provided IOP control and avoidance of traditional surgery for the majority over follow-up averaging 11 months and up to 42 months.

A Comparison of TearCare and Lipiflow Systems in Reducing Dry Eye Disease Symptoms Associated with Meibomian Gland Disease.

Purpose: To compare TearCare and Lipiflow systems in the ability to reduce the symptoms of dry eye disease (DED) associated with meibomian gland dysfunction (MGD). Methods: In this multicenter, masked, randomized-controlled trial, 235 subjects received a single TearCare treatment (n = 115) or a single LipiFlow treatment (n = 120) and were followed for 1-month post-treatment. DED symptoms were assessed using the Ocular Surface Disease Index (OSDI), Symptom Assessment in Dry Eye (SANDE), and Eye Dryness (ED) questionnaires at baseline and at 1 month. Post-hoc subgroup analysis was conducted on subjects with less severe and more severe gland obstruction determined by baseline meibomian gland secretion score (MGSS). Results: TearCare system significantly improved total OSDI, SANDE, and ED scores from baseline (p < 0.0001) at 1-month follow-up. Subjects with more severe disease (MGSS <7) achieved statistically greater reduction with TearCare compared to LipiFlow in total OSDI score (30.4 ± 2.53 and 21.9 ± 2.37, respectively, p ANCOVA = 0.0160), OSDI Section B score for quality of vision (5.1 ± 0.48 and 3.6 ± 0.45, respectively, p ANCOVA= 0.0206), and SANDE frequency score (51.9 ± 3.70 and 41.5 ± 3.45, respectively, p ANCOVA = 0.0455). Conclusion: TearCare provides significant DED symptom relief at 1 month after a single treatment. Outcomes were consistent in OSDI, SANDE, and ED assessments. In subjects with more severe gland dysfunction, TearCare performed significantly better than LipiFlow in improving quality of vision and overall DED symptom frequency determined by OSDI and SANDE. Clinical Trial Registration Number: NCT03857919.

A Multicenter 12-Month Retrospective Evaluation of Canaloplasty and Trabeculotomy in Patients with Open-Angle Glaucoma: The ROMEO 2 Study.

Purpose: Twelve-month safety and effectiveness results for canaloplasty combined with trabeculotomy using the OMNI surgical system in pseudophakic eyes or combined with cataract surgery in mild-to-moderate open-angle glaucoma (OAG). Setting: Sixteen centers in 11 US states (AL, AR, CA, CT, KS, LA, MO, NY, SD, TN, TX). Design: Retrospective, case series, open-label. Methods: A total of 136 eligible patients from 20 surgeons: mild-to-moderate OAG (visual field mean deviation (MD) not worse than -12 dB), 12-month follow-up, preoperative medicated IOP >18 mmHg and ≤36 mmHg on ≤5 medications. One eye per patient enrolled. Endpoints included proportion with ≥20% reduction in IOP or IOP between 6 and 18 mmHg (inclusive) and on the same or fewer medications without secondary surgical intervention (SSI) (primary success), mean IOP, change in IOP, ocular hypotensive medication use, and proportion of patients with a 20% or greater reduction in IOP at 12 months. Safety: adverse events (AE) and best corrected visual acuity (BCVA). Results: Primary success was met by 71%. Mean IOP was reduced (22.3-15.9 mmHg, p < 0.0001). Medications went from 1.9 ± 1.3 to 1.3 ± 1.2 (p < 0.001). AE were mild and as expected for angle surgery. The most frequent AE were BCVA loss (6%), mild inflammation (4%), IOP elevation (3%), and clinically significant hyphema (3%). There were 4 (3%) SSI. Conclusion: The OMNI system provides effective IOP reduction, sustained IOP control, and meaningful medication reduction for up to 12 months postoperative. The present study confirms and extends the results from ROMEO.

Long-term effect of canaloplasty on intraocular pressure and use of intraocular pressure-lowering medications in patients with open-angle glaucoma.

PURPOSE: To assess the long-term safety and effectiveness of canaloplasty in reducing intraocular pressure (IOP) and use of IOP-lowering medications in eyes with open-angle glaucoma (OAG). SETTING: Surgical center (Augencentrum Köln, Köln, Germany). DESIGN: Retrospective study. METHODS: 206 eyes from 130 patients were included. Canaloplasty was performed using the VISCO360 or OMNI surgical system as a stand-alone procedure in 22 eyes and concomitantly with cataract extraction (CE) in 185 eyes with chronic OAG insufficiently controlled or intolerant to IOP-lowering medications. The number of hypotensive medications and IOP were recorded at baseline, day 1, week 1, month 1, month 3, and every 3 months thereafter, with the last follow-up visit at 36 ± 6 months postoperatively. Patients were stratified by baseline IOP (Group 1, IOP >18 mm Hg; Group 2, IOP ≤18 mm Hg). Treatment success in Group 1 was defined as a reduction in IOP and the use of IOP-lowering medications; Group 2 success was defined as maintenance of a lower IOP and a reduction in medication use. RESULTS: The preoperative mean IOP of both groups was 21.1 ± 8.8 mm Hg, with a mean of 2.0 ± 0.9 hypotensive medications. The primary success end point was met by 73% of patients, with a mean IOP reduction in Group 1 (131 eyes; 21.8 to 15.6 mm Hg, P < .0001) and a maintenance of IOP control in Group 2 (76 eyes; 15.4 to 13.9 mm Hg, P = .24). Medications decreased from 2.2 ± 0.9 to 0.9 ± 1.1 in Group 1 ( P = .024) and from 1.8 ± 0.8 to 0.7 ± 1.0 in Group 2 ( P = .003). CONCLUSIONS: Canaloplasty alone or in conjunction with CE with the VISCO360 or OMNI surgical system is a safe, tissue-sparing, and effective minimally invasive glaucoma surgery, using a clear corneal incision in phakic or pseudophakic eyes. Canaloplasty performed with both evaluated devices achieved statistically significant, consistent, and clinically meaningful reductions in IOP and use of IOP-lowering medications in adult patients with OAG. In the consistent cohort (n = 42), the IOP-lowering effect lasted up to 42 months, with ongoing data collection expected to describe long-term effectiveness of this intervention.

Canaloplasty and Trabeculotomy Combined with Phacoemulsification for Glaucoma: 12-Month Results of the GEMINI Study.

Purpose: To report 12-month efficacy outcomes of 360° canaloplasty and 180° trabeculotomy using the OMNI surgical system in combination with phacoemulsification in patients with mild-moderate open-angle glaucoma (OAG) and visually significant cataract. Setting: Fifteen multi-subspecialty ophthalmology practices and surgery centers located in 14 US states. Design: Prospective, multicenter, IRB approved study of patients treated with canaloplasty (360°) and trabeculotomy (180°). Eligible patients had cataract and mild-moderate OAG with intraocular pressure (IOP) ≤33 mmHg on 1 to 4 hypotensive medications. Unmedicated post-washout mean diurnal IOP (DIOP) ≥21 and ≤36 mmHg. Methods: Medication washout preoperatively and prior to month 12 DIOP. Effectiveness outcomes were IOP and IOP lowering medication use. Safety outcomes included adverse events and secondary surgical interventions (SSIs). Evaluations at 1, 3, 6, and 12 months. Results: A total of 149 subjects underwent surgery and 120 were included in the final effectiveness analysis. Mean (standard deviation) unmedicated diurnal IOP was reduced from 23.8 (3.1) mmHg at baseline to 15.6 (4.0) at month 12 (-35%) and medications (before washout) were reduced from 1.8 (0.9) at baseline to 0.4 (0.9) at month 12 (-80%). At month 12, 84.2% of eyes achieved IOP reductions >20% from baseline, 80% of eyes were medication-free, and 76% of eyes achieved IOP between 6-18 mmHg inclusive. Adverse events were uncommon. Most were mild and self-limited including transient hyphema (9 of 149; 6%) and transient IOP elevations (3 of 149; 2.0%). No eyes required SSIs or experienced loss of VA that was attributable to the device or procedure. Conclusion: Canaloplasty and trabeculotomy performed with the OMNI surgical system at the time of phacoemulsification significantly reduces unmedicated mean diurnal IOP and medication use 12 months postoperatively, with an excellent safety profile. This procedure should be considered for eyes with mild-moderate OAG to reduce IOP, medication burden, or both.

TearCare for the Treatment of Meibomian Gland Dysfunction in Adult Patients With Dry Eye Disease: A Masked Randomized Controlled Trial.

PURPOSE: The aim of this study was to demonstrate the safety and effectiveness of a single TearCare procedure compared with a single LipiFlow procedure in treatment of the dry eye disease associated with meibomian gland dysfunction. METHODS: In a multicenter, masked, randomized controlled trial, 135 subjects received a single TearCare (TC) treatment (n = 67) or a single LipiFlow (LF) treatment (n = 68) at baseline and were followed up for 1 month posttreatment. Tear film breakup time, meibomian gland function, and corneal and conjunctival staining scores were assessed as dry eye signs at baseline, 2 weeks, and 1 month; dry eye symptoms were assessed using the Ocular Surface Disease Index, Symptom Assessment in Dry Eye, and eye dryness questionnaires at baseline and 1 month. RESULTS: At 1 month posttreatment, both groups demonstrated significant improvements (P < 0.0001) in mean tear film breakup time and meibomian gland secretion score to 3.0 ± 4.4 and 11.2 ± 11.1 in the TC group and 2.6 ± 3.3 and 11.0 ± 10.4 in the LF group, respectively. The mean eye dryness, Symptom Assessment in Dry Eye, and Ocular Surface Disease Index scores were significantly reduced (P < 0.0001) by 35.4 ± 34.1, 38.2 ± 31.0, and 27.9 ± 20.5 in the TC group and 34.9 ± 26.9, 38.0 ± 25.9, and 23.4 ± 17.7 in the LF group, respectively. There were no statistically significant differences for any result between the groups. However, the TC group demonstrated numerically greater improvements consistently in all signs and symptoms. Device-related ocular adverse events were reported in 3 patients in the TC group (superficial punctate keratitis, chalazion, and blepharitis) and 4 patients in the LF group (blepharitis, 2 cases of foreign body sensation, and severe eye dryness). CONCLUSIONS: A single TearCare treatment significantly alleviates the signs and symptoms of dry eye disease in patients with meibomian gland dysfunction and is equivalent in its safety and effectiveness profile to LipiFlow treatment as shown in this 1-month follow-up study.

Suppression of Diurnal (9AM-4PM) IOP Fluctuations with Minimally Invasive Glaucoma Surgery: An Analysis of Data from the Prospective, Multicenter, Single-Arm GEMINI Study.

PURPOSE: This study analyzes diurnal IOP data (9AM, 12PM, 4PM) from a prospective 12-month trial of the OMNI Surgical System in open-angle glaucoma (OAG) patients with the aim of evaluating effect of MIGS surgery on the amplitude of the diurnal IOP profile pre- and postoperatively. SETTING: Fifteen ophthalmology practices and surgery centers located in 14 states in the United States. DESIGN: Prospective, multicenter, IRB approved study. Patients treated with canaloplasty (360°) and trabeculotomy (180°). Patients had cataract and mild-moderate OAG with intraocular pressure (IOP) ≤33 mmHg on zero to four hypotensive medications. METHODS: Post-hoc analysis of diurnal IOP data from the multicenter GEMINI study. Analysis includes comparison of IOP preoperatively and at month 12 for each of the diurnal time points, 9AM, 12PM, 4PM, change in magnitude of spread between the maximum IOP and minimum IOP for each patient and the proportions of patients preoperatively and at month 12 with IOPs at or below 25, 21, 18, and 15 mmHg, average variability (standard deviation of the 9AM, 12PM, and 4PM IOP) preoperatively and at month 12. RESULTS: A total of 128 patients included in this analysis. IOP at each diurnal timepoint was significantly lower postoperatively (p<0.0001). The difference between highest and lowest IOP measurement for each patient averaged 2.8 mmHg preoperatively (SD 2.4, MAX 14, MIN 0) and 1.8 mmHg (SD 1.7, MAX 10, MIN 0) month 12 (P<0.00001). The proportion with IOP ≤ to 25, 21, 18, and 15 mmHg increased; 75%-97%, 27%-88%, 1%-79%, and <1%-56%, respectively. The average variability was greater at all time points preoperatively (P<0.0001). CONCLUSION: This study demonstrates that eyes with OAG can benefit from an overall decreased IOP and degree of IOP fluctuations for as long as 12 months after surgical treatment with canaloplasty and trabeculotomy.

Canaloplasty and Trabeculotomy Combined with Phacoemulsification in Open-Angle Glaucoma: Interim Results from the GEMINI Study.

PURPOSE: To report interim 6-month safety and efficacy outcomes of 360° canaloplasty and 180° trabeculotomy using the OMNI® Surgical System concomitantly with phacoemulsification in patients with open-angle glaucoma (OAG). SETTING: Fifteen multi-subspecialty ophthalmology practices and surgery centers located in 14 states (Alabama, Arizona, Arkansas, Florida, Georgia, Iowa, Kansas, Montana, Nebraska, North Dakota, Oklahoma, Pennsylvania, Texas, and Wisconsin). DESIGN: Prospective, multicenter, IRB approved study of patients treated with canaloplasty (360°) and trabeculotomy (180°). Eligible patients had cataract and mild-moderate OAG with intraocular pressure (IOP) ≤33 mmHg on 1 to 4 hypotensive medications. METHODS: Medication washout prior to baseline diurnal IOP (Goldmann). Effectiveness outcomes included mean IOP and medications. Safety outcomes included adverse events (AE), best corrected visual acuity (BCVA) and secondary surgical interventions (SSI). Analysis includes descriptive statistics and t-tests evaluating change from baseline. RESULTS: A total of 137 patients were enrolled and treated. Mean diurnal IOP after washout was 23.8 ± 3.1 mmHg at baseline. At month 6, 78% (104/134) were medication free with IOP of 14.2 mmHg, a mean reduction of 9.0 mmHg (38%). 100% (104/104) had a ≥ 20% reduction in IOP and 86% (89/104) had IOP ≥6 and ≤18 mmHg. The mean number of medications at screening was 1.8 ± 0.9 and 0.6 ± 1.0 at month 6. AE included transient hyphema (4.6%) and IOP elevation ≥10 mmHg (2%). There were no AE for loss of BCVA or recurring hyphema. There were no SSI. CONCLUSION: Canaloplasty followed with trabeculotomy and performed concomitantly with phacoemulsification has favorable intra and perioperative safety, significantly reduces IOP and anti-glaucoma medications through 6 months in eyes with mild-moderate OAG.

A Prospective, Post-Market, Multicenter Trial (CHEETAH) Suggested TearCare® System as a Safe and Effective Blink-Assisted Eyelid Device for the Treatment of Dry Eye Disease.

PURPOSE: This study evaluated the safety and effectiveness of TearCare® System to treat the signs and symptoms of dry eye disease (DED). METHODS: In this multicenter, prospective, post-market, exploratory, interventional trial, 58 eyes (29 subjects) received a single TearCare procedure and were assessed at baseline, post-procedure 1-week and 1-month. Effectiveness was assessed as mean change from baseline in tear break-up time (TBUT), Ocular Surface Disease Index (OSDI), total Meibomian Gland Secretion Score (MGSS), and corneal/conjunctival staining. Adverse events (AE) and changes in visual acuity were used to asses safety. RESULTS: The baseline TBUT of 3.7±1.1 seconds was improved by 2.6±1.6 (70%) seconds at 1-week and by 3.1±2.2 (84%) seconds at 1-month (p < 0.0001). Mean baseline OSDI of 54.9±20.2 improved by 17.9±20.9 at 1-week and 25.8±24.3 at 1-month (p < 0.001). A clinically meaningful improvement was seen in 83% of subjects as per the Miller-Plugfelder definition and 66% of subjects improved by at least 1 OSDI category. The baseline MGSS of 5.6±4.0 improved by 9.3±4.0 at 1-week and 8.8±5.8 at 1-month (p < 0.0001). Corneal and conjunctival staining improved by 1.4±2.8 and 1.2±2.9 from a mean baseline of 4.8±2.5 and 5.9±3.2, respectively. Moreover, similar trajectories of improvement were observed for subgroups of subjects stratified by severity. Subjects with more severe gland obstruction at baseline had greater improvements in TBUT and staining compared to the less severe subgroup. No device-related adverse events or significant changes in visual acuity were observed. CONCLUSION: These results suggest that single TearCare procedure is safe and effective in treating signs/symptoms of DED. Significant improvements were seen in all subjects (100%) in all signs and symptoms of DED within 1-week of treatment and 83% subjects experienced clinically meaningful symptom relief. Additionally, TearCare seems to be effective in treating DED associated with all severities of meibomian gland obstruction.

Effect of Povidone Iodine 5% on the Cornea, Vision, and Subjective Comfort.

PURPOSE: To determine the effects of povidone iodine 5% (Betadine 5%) applied to the eye on visual function, corneal integrity, and subjective complaints. METHODS: Ten subjects were chosen to participate in this study (average age 40.6 ± 19.6; age range 22-68). LogMAR acuity, contrast sensitivity, corneal fluorescein staining, and subjective complaints were measured before and after 60 µl of Betadine 5% or saline were applied to one eye (eligibility visit, baseline, 5, 30, and 60 minutes and 4 and 24 hours post-application). Contrast sensitivity at 14 cpd was determined with a spatial two-alternative, forced choice procedure (Beethoven software). The National Eye Institute (NEI) grid pattern was used to grade corneal staining with sodium fluorescein. To avoid the detrimental effects of sodium fluorescein administration on functional vision, the corneal staining baseline was measured at the eligibility visit. Subjective complaints were monitored using the Schein dry eye questionnaire. RESULTS: The data were analyzed with an ANOVA. Saline administration did not alter logMAR acuity, contrast sensitivity, corneal fluorescein staining, or subjective complaints at any visit. Betadine administration significantly reduced the logMAR acuity, compared to baseline and the saline data, at the 30- and 60-minute visits (all P values <.05). The contrast sensitivity was significantly reduced compared to the baseline and the saline results at 5, 30, and 60 minutes after Betadine application (all P values <.05). The Betadine significantly increased the Schein questionnaire score, compared both to baseline and the saline data, at the 1- and 4-hour visits (all P values <.05). Total corneal staining and the maximum NEI sector staining were significantly different from baseline and from the saline results at every visit (all P values <.05). CONCLUSIONS: Betadine 5% application significantly decreases epithelial integrity of the cornea, decreases functional vision, and increases subjective complaints.

Assessment of macular function using the SKILL Card in adults with type 2 diabetes mellitus.

PURPOSE: To evaluate the impact of reduced contrast and reduced luminance on visual acuity (VA) using the Smith-Kettlewell Institute Low Luminance (SKILL) Card in patients with type 2 diabetes mellitus (T2DM). METHODS: We studied adults aged 27 to 65 years, 32 with T2DM and no retinopathy (NoRet group), 22 with T2DM and nonproliferative diabetic retinopathy (NPDR group), and 38 healthy control subjects. Monocular high-contrast (SKILL light) and low-contrast, low-luminance (SKILL dark) near visual acuities were tested. The SKILL score was calculated as the difference between dark chart and light chart acuities and was corrected for age. Contrast sensitivity (CS) was also measured. Subject group differences were examined using ANOVA and Tukey honestly significant difference test. Receiver operating characteristic curve analysis was used to assess the ability of the SKILL Card and CS to discriminate the subject groups. RESULTS: The SKILL score and CS were significantly worse in both diabetes groups compared with the controls (P < 0.01). SKILL scores in the NPDR group were poorest (highest) and significantly worse than those in the NoRet group (P < 0.05). SKILL scores discriminated NPDR and NoRet patients from the controls with high accuracy (99% and 88%, respectively), which was significantly (P < 0.03) better than CS (78% and 74%, respectively). CONCLUSIONS: The SKILL Card demonstrated vision function changes in diabetes even in the absence of clinically evident retinopathy. Diabetic retinopathy led to a further increase in the SKILL score, while high-contrast VA remained unchanged.

Associations between local retinal thickness and function in early diabetes.

PURPOSE: To investigate, using multifocal electroretinography (mfERG) and optical coherence tomography (OCT), potential spatial associations between local neuroretinal function and local retinal thickness in patients with diabetes. METHODS: Forty-five patients without retinopathy (10 with Type 1 diabetes; 35 with Type 2 diabetes; 49.9 ± 10.9 years old) and 29 age-similar controls (47.0 ± 12.8 years old) were studied. N1-P1 amplitude (AMP) and P1 implicit time (IT) of mfERGs within the central approximately 20° diameter were compared to spatially corresponding full retinal thickness measurements acquired by Stratus OCT3. AMP and IT were converted to Z-scores and retinal thickness was converted to percentile values. Local abnormalities were defined as P ≤ 0.023. Subject group differences were examined using t-tests. Retinal thickness was compared to mfERGs to determine spatial associations. RESULTS: Average retinal thicknesses were similar for all subject groups. The Type 1 group and controls had similar IT and AMP. The Type 2 group had reduced AMP and longer IT than the controls and the Type 1 group (P < 0.001). Local associations between retinal thickness and mfERGs were not significant within any subject group or individuals, even for abnormal locations (P ≥ 0.09). Abnormalities in most measures were greater in the patient groups than in the controls (P < 0.008) except retinal thinning in the Type 1 group. CONCLUSIONS: Local neuroretinal function is not associated with full retinal thickness measured locally in patients with diabetes and no retinopathy, even in abnormal locations. Full retinal thickness measured locally by OCT is not a surrogate for mfERGs in early diabetes. Neuroretinal function in Type 2 diabetes is worse than in Type 1 diabetes and controls. Fewer subjects in the Type 1 group could be a potential limitation.

Subclinical capillary changes in non-proliferative diabetic retinopathy.

PURPOSE: To establish adaptive optics scanning laser ophthalmoscopy as a method to detect and characterize microscopic signs of diabetic retinopathy in capillaries and cone photoreceptors in the parafovea. METHODS: Recently, adaptive optics scanning laser ophthalmoscope (AOSLO) has enabled noninvasive assessment of photoreceptors, capillaries, and leukocytes in the retinas of live human subjects. Repeated application of AOSLO imaging along with comparison to fluorescein angiography was used to track individual capillaries near the foveal avascular zone (FAZ) from one eye affected with severe non-proliferative diabetic retinopathy. Fluorescein angiography was used to identify clinical signs of diabetic retinopathy, such as microaneurysms and intraretinal microvascular abnormalities, and corresponding regions were imaged and assessed using the AOSLO. In addition, the structural integrity of photoreceptors and the spatial distribution of leukocytes around the parafoveal capillary network were quantitatively assessed. RESULTS: Capillaries and cone photoreceptors were visualized using the AOSLO without the use of injected contrast agents. Although the majority of capillaries were stable over a period of 16 months, one capillary at the edge of the FAZ dropped out, leading to a small but significant increase in FAZ size. Longitudinal assessment of the capillaries also showed microaneurysm formation and disappearance as well as the formation of tiny capillary bends similar in appearance to intraretinal microvascular abnormalities. The leukocytes in the capillary network were found to preferentially travel through the same routes in all four visits, suggesting that these channels are robust against small changes to the surrounding capillaries. In this eye, cone photoreceptor spacing was increased in the fovea when compared with normal data but stable across all visits. CONCLUSIONS: AOSLO imaging can be used to longitudinally track capillaries, leukocytes, and photoreceptors in diabetic retinopathy. Capillary changes that can be detected include dropout of individual capillaries as well as formation and disappearance of microaneurysms.

Disruption of the retinal parafoveal capillary network in type 2 diabetes before the onset of diabetic retinopathy.

PURPOSE: To establish, using adaptive optics scanning laser ophthalmoscopy (AOSLO), that the retinal parafoveal capillary network is altered before the onset of diabetic retinopathy in adult patients with type 2 diabetes. METHODS: AOSLO videos were acquired in the parafoveal region of one eye from control subjects and from patients with type 2 diabetes and no retinopathy. Detailed images of the parafoveal capillary network were generated with custom motion contrast enhancement algorithms. The combination of AOSLO images and videos enabled the simultaneous assessment of several features of the parafoveal capillary network. Arteriovenous (AV) channels were identified by finding the least tortuous capillary channels connecting terminal arterioles to postcapillary venules. Measures of capillary dropout and capillary hemodynamics were also quantified. RESULTS: The average tortuosity of AV channels was 26% higher in patients with type 2 diabetes when compared with controls, even though there were no signs of diabetic retinopathy in any of the eyes that were assessed (P < 0.05). In addition, the metrics of capillary dropout showed small changes (between 3% and 7%), leukocyte speed 14% lower, and pulsatility 25% higher, but none of these differences was statistically significant. CONCLUSIONS: It is often difficult to find consistent changes in the retinal microvasculature due to large intersubject variability. However, with a novel application of AOSLO imaging, it is possible to visualize parafoveal capillaries and identify AV channels noninvasively. AV channels are disrupted in type 2 diabetes, even before the onset of diabetic retinopathy.