Early choroidal and retinal changes detected by swept-source oct in type 2 diabetes and their association with diabetic kidney disease: a longitudinal prospective study.

BACKGROUND: To evaluate structural changes in retina and choroid in patients with type 2 diabetes (T2D) and their association with diabetic kidney disease (DKD). METHODS: T2D patients with mild or no diabetic retinopathy (DR) were followed for 3 years using structural SS-OCT and OCT angiography (OCT-A) taken every 6 months. Parameters were compared longitudinally and according to the DKD status on baseline. RESULTS: One hundred and sixty eyes from 80 patients were followed for 3 years, 72 with no DKD (nDKD) at baseline and 88 with DKD. Trend analysis of T2D showed significant thinning in GCL + and circumpapillary retinal fiber neural layer (cRFNL), choroid, and decreased vascular density (VD) in superficial plexus and central choriocapillaris with foveal avascular zone (FAZ) enlargement. Patients with no DKD on baseline presented more significant declines in retinal center and choroidal thickness, increased FAZ and loss of nasal and temporal choriocapillaris volume. In addition, the nDKD group had worse glycemic control and renal parameters at the end of the study. CONCLUSION: Our data suggests the potential existence of early and progressive neurovascular damage in the retina and choroid of patients with Type 2 Diabetes (T2D) who have either no or mild Diabetic Retinopathy (DR). The progression of neurovascular damage appears to be correlated with parameters related to glycemic control and renal damage.

FUNCTIONAL AND STRUCTURAL EFFECTS OF NONDAMAGING RETINAL LASER THERAPY FOR MACULAR TELANGIECTASIA TYPE 2: A Randomized Sham-Controlled Clinical Trial.

PURPOSE: Macular telangiectasia (MacTel) Type 2 is a progressing neurovascular disease of the macula, currently lacking effective treatment. This study assessed the effect of nondamaging retinal laser therapy (NRT) compared with sham. METHODS: Twelve MacTel patients were enrolled in this double-masked, controlled, randomized clinical trial. For the nine patients with both eyes eligible, one eye was randomized to NRT or sham and the other received alternate treatment. For three patients with only one eye eligible, that eye was randomly assigned either NRT or sham. Ellipsoid zone disruption, best-corrected visual acuity, and macular automated perimetry at 12 months served as structural and functional measures. RESULTS: Eleven eyes were randomized to sham and 10 to NRT. Baseline best-corrected visual acuity was 66 letters (20/50) for sham and 72 letters (20/40) for NRT (P = 0.245). Ellipsoid zone disruption area was 298 µm2 in sham and 368 µm2 in NRT (P = 0.391). At 12 months, ellipsoid zone disruption increased by 24% in sham and decreased by 34% in NRT (P < 0.001). Best-corrected visual acuity measures remained stable during follow-up compared with baseline. At 1 year, the mean macular sensitivity was 28 dB in the NRT group, compared with 26 dB in sham. CONCLUSION: Nondamaging retinal laser therapy was safe and well tolerated in patients with MacTel and resulted in structural and functional improvements, which could represent a protective effect of laser-induced hyperthermia. Longer follow-up and larger number of patients should help corroborate these effects.

Swept Source Optical Coherence Tomography Documenting Optic Nerve Involvement in an Aggressive T-Cell Lymphoma.

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of aggressive neoplasms. The involvement of ocular structures in haematological neoplasms is rare and usually associated with central nervous system involvement, which may occur as a result of orbital invasion and optic nerve infiltration. In this case report, we describe ocular findings using the novel swept source optical coherence tomography (SS-OCT) in a case of aggressive T-cell lymphoma. SS-OCT has faster scanning speed, deeper tissue penetration due to its longer wavelength laser of 1050 nm and wider scanning areas. In the present case, SS-OCT was helpful in documenting increased retinal nerve fibre layer thickness and prelaminar protrusion associated with visual loss in a patient with an aggressive T-cell lymphoma.

Plasma levels of miR-29b and miR-200b in type 2 diabetic retinopathy.

MicroRNAs (miRNAs/miRs) are involved in the pathogenesis of diabetes mellitus and its chronic complications, and their circulating levels have emerged as potential biomarkers for the development and progression of diabetes. However, few studies have examined the expression of miRNAs in diabetic retinopathy (DR) in humans. This case-control study aimed to investigate whether the plasma levels of miR-29b and miR-200b are associated with DR in 186 South Brazilians with type 2 diabetes (91 without DR, 46 with non-proliferative DR and 49 with proliferative DR). We also included 20 healthy blood donors to determine the miRNA expression in the general population. Plasma levels of miR-29b and miR-200b were quantified by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Proliferative DR was inversely associated with plasma levels of miR-29b (unadjusted OR = 0.694, 95% CI: 0.535-0.900, P = 0.006) and miR-200b (unadjusted OR = 0.797, 95% CI: 0.637-0.997, P = 0.047). However, these associations were lost after controlling for demographic and clinical covariates. In addition, patients with type 2 diabetes had lower miR-200b levels than blood donors. Our findings reinforce the importance of addressing the role of circulating miRNAs, including miR-29 and miR-200b, in DR.

Ophthalmological and Neurologic Manifestations in Pre-clinical and Clinical Phases of Spinocerebellar Ataxia Type 7.

Spinocerebellar ataxia type 7 (SCA7) is a polyglutamine disease that progressively affects the cerebellum, brainstem, and retina. SCA7 is quite rare, and insights into biomarkers and pre-clinical phases are still missing. We aimed to describe neurologic and ophthalmological findings observed in symptomatic and pre-symptomatic SCA7 subjects. Several neurologic scales, visual acuity, visual fields obtained by computer perimetry, and macular thickness in optical coherence tomography (mOCT) were measured in symptomatic carriers and at risk relatives. Molecular analysis of the ATXN7 was done blindly in individuals at risk. Thirteen symptomatic carriers, 3 pre-symptomatic subjects, and 5 related controls were enrolled. Symptomatic carriers presented scores significantly different from those of controls in most neurologic and ophthalmological scores. Gradual changes from controls to pre-symptomatic and then to symptomatic carriers were seen in mean (SD) of visual fields - 1.34 (1.15), - 2.81 (1.66). and - 9.56 (7.26); mOCT - 1.11 (2.6), - 3.48 (3.54), and - 7.73 (2.56) Z scores; and "Spinocerebellar Ataxia Functional Index (SCAFI)" - 1.16 (0.28), 0.65 (0.56), and - 0.61 (0.44), respectively. Visual fields and SCAFI were significantly correlated with time to disease onset (pre-symptomatic)/disease duration (symptomatic carriers). Visual fields, mOCT, and SCAFI stood out as candidates for state biomarkers for SCA7 since pre-symptomatic stages of disease.

Choroidal thickness in preeclampsia measured by spectral-domain optical coherence tomography.

PURPOSE: To compare choroidal thickness (CT) measurements in preeclamptic and healthy women in the third trimester of pregnancy using optical coherence tomography. METHODS: This cross-sectional study included 148 eyes of 74 women, divided into two groups: 27 healthy pregnant women in the third trimester (control group) and 47 age-matched pregnant women in the third trimester with preeclampsia (PE group). Of the 47 subjects in preeclampsia group, 26 were classified as having mild PE and 21 as having severe PE. Choroidal thickness was measured at ten different locations: at the fovea and every 500 µm from the fovea up to 2500 µm temporally and up to 2000 µm nasally. RESULTS: Comparing CT of both groups, choroid always tended to be thicker in subjects with preeclampsia in comparison with healthy pregnant women, with statistical significance in nasal measures. Dividing PE group according to disease severity, women with severe preeclampsia tended to have thicker choroids in comparison with mild preeclamptic and healthy pregnant women. Choroid was also significantly thicker in preeclamptic patients with serous retinal detachment (SRD) in comparison with preeclamptic patients without SRD (P < 0.01 in all macular points). CONCLUSION: Our study showed that choroid tends to be thicker in patients with preeclampsia, with statistical significance only in nasal measures. In patients with SRD, however, choroid is markedly thicker at all points analyzed. From these findings we can hypothesize that preeclampsia can cause a choroidal thickening, which begins in the peripapillary area. As the imbalance increases, the entire choroid becomes thickened.

Nondamaging photothermal therapy for the retina: initial clinical experience with chronic central serous retinopathy.

PURPOSE: To assess safety and clinical efficacy of the nondamaging photothermal therapy for the macula for the treatment of chronic central serous retinopathy. METHODS: Sixteen eyes of 16 patients with persistent central serous retinopathy (>4 months of duration) were treated with the PASCAL Streamline) at 577-nm wavelength, using 200-µm retinal spot sizes. Using Endpoint Management Software, the laser power was first titrated for a barely visible burn with 15-ms pulses, which was defined as 100% pulse energy. Treatment was then applied over the area of serous retinal detachment and adjacent nonthickened retina, using 30% pulse energy with the spot spacing of 0.25 beam diameter. Changes in subretinal fluid, Early Treatment Diabetic Retinopathy Study best-corrected visual acuity, and central macular thickness were measured over 6 months of follow-up. Pretreatment and posttreatment fluorescein angiography and fundus autofluorescence were also assessed. RESULTS: On average, 532 spots have been applied per treatment. No visible laser marks could be detected by clinical observation, optical coherence tomography, fundus autofluorescence, or fluorescein angiography. On average, 12 Early Treatment Diabetic Retinopathy Study letters gain was achieved at 2 months and was sustained by 6 months (P < 0.001). Central macular thickness decreased from 350 µm to 282 µm (P = 0.004). Subretinal fluid completely resolved in 37% of the patients after first treatment, whereas 44% of the patients required retreatment after 3 months because of recurrent fluid or incomplete resolution. The remaining 19% of the patients received a second retreatment. By 6 months, in 75% of the patients, the subretinal fluid was completely resolved, whereas in 25%, there was some minimal fluid left. CONCLUSION: Photothermal therapy using 577-nm PASCAL laser with Endpoint Management graphic user interface was safe, and it improved visual acuity and resolution of subretinal fluid in chronic central serous retinopathy. Lack of tissue damage allows periodic retreatment without cumulative scaring, characteristic to conventional photocoagulation. This technique should be tested in the treatment of other macular disorders and may offer an alternative to conventional laser coagulation of the macula and to anti-vascular endothelial growth factor pharmacological treatments of macular diseases.

Restoration of retinal structure and function after selective photocoagulation.

CNS neurons change their connectivity to accommodate a changing environment, form memories, or respond to injury. Plasticity in the adult mammalian retina after injury or disease was thought to be limited to restructuring resulting in abnormal retinal anatomy and function. Here we report that neurons in the mammalian retina change their connectivity and restore normal retinal anatomy and function after injury. Patches of photoreceptors in the rabbit retina were destroyed by selective laser photocoagulation, leaving retinal inner neurons (bipolar, amacrine, horizontal, ganglion cells) intact. Photoreceptors located outside of the damaged zone migrated to make new functional connections with deafferented bipolar cells located inside the lesion. The new connections restored ON and OFF responses in deafferented ganglion cells. This finding extends the previously perceived limits of restorative plasticity in the adult retina and allows for new approaches to retinal laser therapy free of current detrimental side effects such as scotomata and scarring.

Does microperimetry have a prognostic value in central serous chorioretinopathy?

PURPOSE: To investigate the relationship between retinal sensitivity and persistence of subretinal fluid and then to analyze microperimetry as a prognostic predictor of acute central serous chorioretinopathy. METHODS: A prospective observational study. Fourteen eyes of 14 patients presenting with first episode acute central serous chorioretinopathy were enrolled and underwent ocular examination, spectral domain optical coherence tomography, and MAIA microperimetry were performed. After three months of follow-up, without any treatment, visual acuity and spectral domain optical coherence tomography macular thickness assessments and microperimetry were repeated. The main outcome was to find a relation between initial macular sensitivity and persistence of subretinal fluid. A receiver operating characteristic curve was plotted to indicate the best macular sensitivity cutoff point that would be able to predict whether a patient with acute central serous chorioretinopathy would progress to the chronic form. According to the cutoff, we calculated the sensitivity, specificity, and positive and negative predictive values for macular sensitivity as a method to predict persistence of subretinal fluid. RESULTS: On the basis of the receiver operating characteristic curve, a cutoff of 20 dB macular sensitivity was obtained, as the best balance between sensitivity and specificity to predict chronicity. Using this cutoff, the method had a sensitivity of 71% and specificity of 100% with a positive predictive value of 100% and negative predictive value of 78%. Furthermore, it was found that eyes with acute central serous chorioretinopathy and microperimetry of less than 20 dB had a relative risk of 4.5 to develop subretinal fluid persistence. CONCLUSION: Microperimetry with a cutoff of 20 dB may be a useful test to predict the persistence of subretinal fluid, allowing the ophthalmologist to use treatment tools earlier, preventing extracellular damage and visual impairment.

Subvisible retinal laser therapy: titration algorithm and tissue response.

PURPOSE: Laser therapy for diabetic macular edema and other retinal diseases has been used within a wide range of laser settings: from intense burns to nondamaging exposures. However, there has been no algorithm for laser dosimetry that could determine laser parameters yielding a predictable extent of tissue damage. This multimodal imaging and structural correlation study aimed to verify and calibrate a computational model-based titration algorithm for predictable laser dosimetry ranging from nondamaging to intense coagulative tissue effects. METHODS: Endpoint Management, an algorithm based on a computational model of retinal photothermal damage, was used to set laser parameters for various levels of tissue effect. The algorithm adjusts both power and pulse duration to vary the expected level of thermal damage at different percentages of a reference titration energy dose. Experimental verification was conducted in Dutch Belted rabbits using a PASCAL Streamline 577 laser system. Titration was performed by adjusting laser power to produce a barely visible lesion at 20 ms pulse duration, which is defined as the nominal (100%) energy level. Tissue effects were then determined for energy levels of 170, 120, 100, 75, 50, and 30% of the nominal energy at 1 hour and 3, 7, 30, and 60 days after treatment. In vivo imaging included fundus autofluorescence, fluorescein angiography, and spectral-domain optical coherence tomography. Morphologic changes in tissue were analyzed using light microscopy, as well as scanning and transmission electron microscopy. RESULTS: One hundred and seventy percent and 120% levels corresponded to moderate and light burns, respectively, with damage to retinal pigment epithelium, photoreceptors, and at highest settings, to the inner retina. 50% to 75% lesions were typically subvisible ophthalmoscopically but detectable with fluorescein angiography and optical coherence tomography. Histology in these lesions demonstrated some selective damage to retinal pigment epithelium and photoreceptors. The 30% to 50% lesions were invisible with in vivo multimodal imaging, and damage was limited primarily to retinal pigment epithelium, visible best with scanning electron microscopy. Over time, photoreceptors shifted into the coagulated zone, reestablishing normal retinal anatomy in lesions ≤100%, as seen in optical coherence tomography and light microscopy. Transmission electron microscopy at 2 months demonstrated restoration of synapses between shifted-in photoreceptors and bipolar cells in these lesions. Retinal pigment epithelium monolayer restored its continuity after 1 week in all lesions. No damage could be seen <30% level. CONCLUSION: A retinal laser dosimetry protocol based on the Endpoint Management algorithm provides reproducible changes in retinal morphology in animals with various levels of pigmentation. This algorithm opens doors to clinical trials of well-defined subvisible and nondestructive regimes of retinal therapy, especially important for treatment of macular disorders.

Effect of intravitreal triamcinolone acetonide on healing of retinal photocoagulation lesions.

PURPOSE: To evaluate the effect of intravitreal triamcinolone acetonide (TA) on healing of retinal photocoagulation lesions using drug and laser dosing typically employed in clinical practice. METHODS: Laser burns with a 267-µm retinal beam size at 532-nm wavelength were applied to 40 eyes of Dutch belted rabbits. Barely visible to intense lesions were produced with pulses of 5, 10, 20, and 50 milliseconds and power of 175 mW. Eyes received intravitreal injections of either 2 mg TA/50 µL or balanced salt solution administered either 1 week before or immediately after laser treatment. Lesion grades were assessed acutely ophthalmoscopically and by a masked observer histologically at 1, 3, 7, 30, and 60 days. RESULTS: Both TA groups demonstrated significant reduction in retinal thickness throughout follow-up compared with balanced salt solution groups (P < 0.001). The width of the lesions at 1 day after injection was not significantly different between groups. However, by 7 days, the lesions in balanced salt solution groups contracted much more than in the TA groups, especially the more intense burns, and this difference persisted to 2 months. The healing rate of the barely visible burns was not significantly affected by TA compared with the balanced salt solution control eyes. CONCLUSION: Triamcinolone acetonide injection previously or concurrently with photocoagulation significantly decreases laser-induced edema but interferes with lesions healing, thereby leaving wider residual scarring, especially persistent in more intense burns.

Early retinal neurovascular findings in post-transplant diabetes mellitus patients without clinical signs of diabetic retinopathy.

BACKGROUND: Post-transplant diabetes mellitus (PTDM) is a specific subtype of diabetes with an uncertain impact on mortality and morbidity in post-transplant patients. Diabetic retinopathy is the most common microvascular complication of diabetes mellitus, but the long-term clinical progression in PTDM is unknown. New technologies are being used to assess pre-clinical signs of retinal changes, such as swept-source optical coherence tomography (OCT) and OCT-angiography. The aim of this study was to detect pre-clinical structural and vascular changes in the retina using swept-source-OCT and OCT-angiography in patients with PTDM. METHODS: In this retrospective cohort study, post-kidney transplant patients were divided into PTDM and non-PTDM (control) groups. Both eyes of eligible PTDM patients and controls were included in this study. Inner retinal layer thickness was measured with swept-source-OCT. Retinal capillary density and the foveal avascular zone were measured with OCT-angiography. RESULTS: In the PTDM group, reduced thickness was found in the inferior ganglion cell layer plus inner plexiform layer (95% CI -8.76 to -0.68; p = 0.022) and the temporal inferior segment (95% CI -10.23 to -0.76; p = 0.024) of the inner retina, as well as in the retinal nerve fiber layer in the temporal (95% CI -34.78 to -9.28 p = 0.001) and temporal inferior segments (95% CI -33.26 to -5.03 p = 0.008). No significant differences were found in the vascular capillary plexus between groups at all depths, segments, or foveal avascular zone (p = 0.088). CONCLUSIONS: According to OCT-angiography, PTDM patients had reduced inner neurosensory retinal layers but no significant change in vascular density, which suggests that early neuroretinal degeneration might occur prior to vascular changes secondary to PTDM. Prospective studies could help elucidate the clinical course of retinal neuropathy and microvascular pathology in PTDM and provide a better understanding of PTDM complications.

Organizational intervention to improve access to retinopathy screening for patients with diabetes mellitus: health care service improvement project in a tertiary public hospital.

INTRODUCTION: The aim of this study was to improve the access to diabetic retinopathy (DR) screening with retinographies in a tertiary care center through a process conducted by an interdisciplinary group driven by a nurse. MATERIALS AND METHODS: This is a quality improvement study that evaluated the flow for DR screening conducted by an interdisciplinary group using the Plan-Do-Study-Act methodology. As a result measure, we assessed the quantity of retinographies performed after the project implementation, the proportion of patients who presented abnormal retinographies, and the proportion of patients referred to a specialist. RESULTS: The new patient screening flow and the reinforcement of available human resources led to an increase in the number of retinographies performed and screened patients. A total of 1184 retinographies were conducted, and it was possible to observe DR alterations in 37.8 % patients, of which only 6 % needed to be referred to the DR reference center. CONCLUSIONS: This study showed a significant increase in the number of retinographies performed. The Plan-Do-Study-Act methodology was an important tool to improve the flow of patient access to fundus images, helping to consistently and continuously improve these processes.

Optic Nerve Head Changes After Intraocular Pressure-Lowering Glaucoma Surgeries Using Optical Coherence Tomography.

PRCIS: Optic nerve head (ONH) changes were detected with swept-source optical coherence tomography (SS-OCT) after intraocular pressure (IOP)-lowering glaucoma surgeries. PURPOSE: The aim of this study was to detect changes in the ONH with SS-OCT after IOP-lowering procedures. PATIENTS AND METHODS: Patients with progressing glaucoma who were referred for IOP-lowering procedures were included. The participants underwent a 24-2 visual field test and SS-OCT (DRI OCT Triton Plus; Topcon). IOP and SS-OCT scans were obtained during the preoperative period and up to 7 days and 30-90 days postoperatively. ONH parameters were measured with a B -scan at the center of the optic disc and an average of 5 central B -scans. The hypotenuse of the ONH cup (HOC) was calculated using the Pythagorean theorem: hypotenuse 2 = leg1 2 + leg2 2 , considering the length and depth of the cup as the legs of a right triangle. We also evaluated changes in Bruch membrane opening (BMO)-to-BMO diameter. Statistical analysis was performed using generalized estimating equations. RESULTS: A total of 15 eyes were included. The mean patient age was 70 (SD, 11.04) years. The mean circumpapillary retinal nerve fiber layer was 60.13 (SD, 23.21) µm and the visual field mean deviation was -13.29 (SD, 8.5) dB. The mean IOP at each visit was: 20.5 (SD, 4.99); 11 (SD, 4.95), and 15.7 (SD, 5.04), respectively. The mean HOC, the mean depth and length of the ONH cup, and the BMO-to-BMO diameter decreased significantly after the IOP-lowering procedures. CONCLUSIONS: The HOC evaluated with SS-OCT significantly decreased after IOP-lowering surgeries. This parameter was useful for evaluating short-term changes in the ONH.

Spectral-domain optical coherence tomography in patients with commotio retinae.

PURPOSE: To describe the morphologic characteristics of commotio retinae using spectral-domain optical coherence tomography and to evaluate its utility in prognosis and follow-up. METHODS: Consecutive patients with commotio retinae underwent complete ophthalmic examination, color fundus photography, spectral-domain optical coherence tomography, fundus autofluorescence, and near-infrared autofluorescence. RESULTS: There were 11 eyes of 11 patients (8 men), with a mean age of 30.8 ± 12.1 years. The follow-up ranged from 9 days to 6 months. Spectral-domain optical coherence tomography identified hyperreflectivity underneath the inner/outer segment junction in the area of commotio retinae in 9 patients (81.1%), which subsided in a few days. Five patients (45.5%) revealed areas of disruption of the inner/outer segment junction and hyperreflectivity of the overlying retina, which progressed to external retinal atrophy and visual loss (P = 0.002). The 5 patients with visual sequelae revealed pigment disorders and alterations in fundus autofluorescence and near-infrared autofluorescence during follow-up, and 3 patients (60%) presented with intraretinal hemorrhages. CONCLUSION: Spectral-domain optical coherence tomography of mild lesions with good visual outcome showed transient hyperreflectivity of the outer retina. The cases with severe trauma were related to acute disruption of the inner/outer segment junction and hyperreflectivity of the overlying retina and were regularly associated with retinal atrophy, pigment disturbance, and poor visual prognosis.

Early choroidal changes detected by swept-source OCT in type 2 diabetes and their association with diabetic kidney disease.

INTRODUCTION: Microvascular changes in eye and kidney shares some common factors in diabetes mellitus (DM). The purpose was to evaluate choroidal thickness (CT) and choriocapillaris (CC) density in patients with type 2 diabetes (T2D) and their association with diabetic kidney disease (DKD) using swept-source optical coherence tomography (SS-OCT). RESEARCH DESIGN AND METHODS: A cross-sectional study was conducted with patients with T2D with mild or no diabetic retinopathy (DR) and non-diabetic controls. CT was measured with SS-OCT, and CC vascular density was measured with OCT angiography. These parameters were compared with inner retinal layers thickness in patients with and without DKD and non-diabetic controls. RESULTS: Ninety-three eyes from patients with T2D and 34 eyes from controls volunteers were included. Within the T2D group, 56 eyes with DKD and 37 eyes from patients with no diabetic kidney disease were examined. A statistically significant reduction of CT was observed in patients with DKD compared with controls, with no difference in CC density. There was an association between ganglion cell layer and central choroidal thickness reduction in the DKD group. CONCLUSIONS: Patients with T2D with DKD showed a decrease in CT with no difference in CC density compared with non-diabetic controls. This thinning might be related to vascular changes of choroidal layers such as Haller's and Sattler's with preservation of CC density, which is crucial for outer retina and retinal pigment epithelium health. Longitudinal studies are warranted to determine the association of choroidal changes with the pathogenesis of diabetes, and its association with early DKD and progression to more severe DR.

The impact of pulse duration and burn grade on size of retinal photocoagulation lesion: implications for pattern density.

PURPOSE: Shorter pulses used in pattern scanning photocoagulation (10-20 milliseconds [ms]) tend to produce lighter and smaller lesions than the Early Treatment Diabetic Retinopathy Study standard 100-ms exposures. Smaller lesions result in fewer complications but may potentially reduce clinical efficacy. It is worthwhile to reevaluate existing standards for the number and size of lesions needed. METHODS: The width of the coagulated zone in patients undergoing retinal photocoagulation was measured using optical coherence tomography. Lesions of "moderate," "light," and "barely visible" clinical grades were compared for 100, 200, and 400 µm spot sizes and pulse durations of 20 ms and 100 ms. RESULTS: To maintain the same total area as in 1,000 standard burns (100 ms, moderate) with a 400-µm beam, a larger number of 20-ms lesions are required: 1,464, 1,979, and 3,520 for moderate, light, and barely visible grades, respectively. Because of stronger relative effect of heat diffusion with a smaller beam, with 200 µm this ratio increases: 1,932, 2,783, and 5,017 lesions of 20 ms with moderate, light, and barely visible grades correspond to the area of 1,000 standard burns. CONCLUSION: A simple formula is derived for calculation of the required spot spacing in the laser pattern for panretinal photocoagulation with various laser parameters to maintain the same total coagulated area.

Health-related quality of life associated with diabetic retinopathy in patients at a public primary care service in southern Brazil.

OBJECTIVE: This study aimed to establish the utility values of different health states associated with diabetic retinopathy in a Brazilian sample to provide input to model-based economic evaluations. METHODS: This cross-sectional study was performed in a sample of patients with type 2 diabetes mellitus (T2D) who underwent teleophthalmology screening at a primary care service from 2014 to 2016. Five diabetic retinopathy health states were defined: absent, non-sight-threatening, sight-threatening, and bilateral blindness. Utility values were estimated using the Brazilian EuroQol five dimensions (EQ-5D) tariffs. Descriptive statistics were calculated. Analysis of covariance was performed to adjust the utility values for potential confounders. RESULTS: The study included 206 patients. The mean (± standard deviation [SD]) utility value was 0.765 ± 0.19 (95% confidence interval [CI], 0.740-0.790). The adjusted mean utility value was 0.748 (95% CI, 0.698-0.798) in patients without diabetic retinopathy, 0.752 (95% CI, 0.679-0.825) in those with non-sight-threatening state, 0.628 (95% CI, 0.521-0.736) in those with sight-threatening state, and 0.355 (95% CI, 0.105-0.606) in those with bilateral blindness. A significant utility decrement was found between patients without diabetic retinopathy and those with a sight-threatening health state (0.748 vs. 0.628, respectively, p = 0.04). CONCLUSION: The findings suggest that a later diabetic retinopathy health state is associated with a decrement in utility value compared with the absence of retinopathy in patients with T2D. The results may be useful as preliminary input to model-based economic evaluations. Further research is needed to investigate the impact of diabetic retinopathy on health-related quality of life in a sample more representative of the Brazilian population.

Early neurovascular retinal changes detected by swept-source OCT in type 2 diabetes and association with diabetic kidney disease.

PURPOSE: To evaluate retinal thickness and capillary density in patients with type 2 diabetes (T2D) and their association with diabetic kidney disease (DKD) using swept-source optical coherence tomography (SS-OCT). METHODS: A cross-sectional study was conducted with T2D patients with mild or no diabetic retinopathy (DR) and nondiabetic controls. Inner retinal layer thickness was measured with SS-OCT. Retinal capillary density and the foveal avascular zone (FAZ) were measured with SS-OCT angiography (OCTA). SS-OCT parameters were compared in patients with and without diabetic kidney disease (DKD) and nondiabetic controls. RESULTS: 131 DKD eyes showed decreased ganglion cell layer plus (GCL+) (p = 0.005 TI; p = 0.022 I), retinal nerve fiber layer (RNFL) (p = 0.003), and central retinal thickness (CRT) (p = 0.032), as well as foveal avascular zone (FAZ) enlargement (p = 0.003) and lower capillary density in the superficial vascular plexus (p = 0.016, central quadrant), compared to controls. No statistically significant changes were found between diabetic patients without significant DKD and controls. CONCLUSION: Our findings suggest early neurovascular damage in patients with T2D; these changes were more significant in patients with DKD. Larger longitudinal studies are warranted to determine the role of early neurovascular damage in the pathophysiology of severe DR.