Photocoagulation For Diabetic Retinopathy Research Articles

Long-term longitudinal retinal changes after conventional and pattern scan laser panretinal photocoagulation in diabetic retinopathy

PurposeComparison the effect of conventional and pattern scan laser (PASCAL) panretinal photocoagulation (PRP) on macula and optic disk in diabetic retinopathy (DR). MethodsThis retrospective study included 57 patients. In the conventional laser group, PRP was completed using the LightMed LightLas 532 laser device in accordance with the ETDRS protocol. In the pattern laser group, it was completed in a single session using PASCAL device with 20 ms pulse duration and multispot pattern. Central macular thickness (CMT) and retinal nerve fiber layer (RNFL) thickness were evaluated before laser treatment and at 1, 6 and 12 months after treatment. ResultsThere were 30 eyes in the conventional laser group and 27 eyes in the PASCAL group. There was no significant difference between the groups in terms of age (p = 0.560), sex (p = 0.866), duration (p = 0.498) and stage (p = 0.503) of diabetes, visual acuity (p = 0.104) and intraocular pressure (p = 0.963).In both groups, CMT increased significantly (p ˂0.001), while RNFL thickness decreased significantly (p ˂0.001) at 12 months. While CMT and mean RNFL thickness increased in the first month in both groups, it decreased progressively until the 12th month. ConclusionConventional and pattern laser systems used in the treatment of DR................ cause an increase in CMT and thinning of RNFL thickness in the long term. This change is more in the conventional laser group compared to the pattern laser.

Topical anesthesia versus topical and subconjunctival anesthesia combined in diabetic retinopathy photocoagulation.

comparison between two anesthetic techniques on the ability to reduce pain during panretinal photocoagulation (PRP) treatment. Observational retrospective single center study. Medical charts of patients who underwent PRP for proliferative diabetic retinopathy were revised. Patients were included if they had the first eye treated with oxybuprocaine hydrochloride drops, and in case of severe pain, the fellow eye received topical anesthesia in combination with 2% subconjunctival lidocaine. The groups were compared for pain perception using an analog visual scale (VAS), number of laser spots, number of interruptions, and laser session duration. Forty-two eyes of 21 patients (mean age: 58.3 ± 7.6 years) were analyzed. The mean number of laser spots was significantly higher under combined anesthesia (+84.2 ± 155.9 spots, p = 0.01), with a reduced time for laser execution (-2.5 ± 3.12, p = 0.0008). The use of combined anesthesia significantly decreased the number of interruptions (-40.8%, p < 0.0001) into a single session. On the pain grading scale, the pain perception was significantly lower in the combined anesthesia group (p < 0.0001). In eyes receiving topical anesthesia the treatment was stopped for pain in 5 eyes (23.8%), while 5 eyes under combined anesthesia presented subconjunctival hemorrhage (23.8%). Using combined anesthesia in patients subjected to PRP appeared to reduce pain perception limiting the treatment duration and the interruptions for pain without significant complications. Further studies on a larger scale would be desirable to replicate such findings and standardize the analgesic procedures in ophthalmology.

Efficacy of ranibizumab combined with photocoagulation for diabetic retinopathy: A meta-analysis study.

Ranibizumab addition may benefit to improve the efficacy in patients with diabetic retinopathy than only photocoagulation, and this meta-analysis aims to explore the impact of ranibizumab addition on efficacy for diabetic retinopathy. PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases were systematically searched, and we included randomized controlled trials assessing the effect of ranibizumab addition on patients with diabetic retinopathy for this meta-analysis. Six randomized controlled trials were finally included in the meta-analysis. Overall, compared with control intervention for diabetic retinopathy, ranibizumab addition showed significantly increased number of neovascularization area reduction (OR = 4.20; 95% CI = 1.47-12.02; P = .007) and reduced fluorescein leakage (MD = -2.53; 95% CI = -3.31 to -1.75; P < .00001), but showed no obvious impact on neovascularization area (MD = -1.80; 95% CI = -3.68 to 0.08; P = .06), photocoagulation retreatment (OR = 1.03; 95% CI = 0.47-2.27; P = .94) or adverse events (OR = 1.45; 95% CI = 0.49-4.29; P = .50). Ranibizumab combined with photocoagulation is effective to improve efficacy for diabetic retinopathy.

Vision-Related Quality of Life and Treatment Satisfaction Following Panretinal Photocoagulation in Diabetic Retinopathy-A Panel Study.

Background and Objectives: The aim of the study was to evaluate vision-related quality of life (VR-QOL) and treatment satisfaction (TS) in patients with diabetic retinopathy treated with panretinal photocoagulation (PRP). Material and Methods: The panel study included 95 patients who underwent PRP for diabetic retinopathy. Eligible patients with no history of previous PRP were interviewer-administered the National Eye Institute Visual Function Questionnaire (NEI VFQ-25) and Retinopathy Treatment Satisfaction Questionnaire (RetTSQ) beforehandand one month after the last session of laser application. The study was conducted between June 2017 and June 2019 at tertiary care center in Serbia, Belgrade. We assessed pre- to post-PRP values of the composite score and subscale scores of VFQ-25 and RetTSQ, using a paired samples t-test. Univariate logistic regression was used to analyze the relationship between binary outcomes and potential predictors. Multivariate regression included predictors from univariate analyses that were statistically significant. Results: The mean VFQ-25 composite score was 65.4 ± 17.4 before and 63.3 ± 19.5 after PRP (p = 0.045). Subscale analysis showed that two of the 11 items achieved a significant decrease after laser application (general vision and dependency). The mean RetTSQ score at baseline was 60.0 ± 11.8 and at the exit visit was 60.3 ± 12.3 (p = 0.858). Sub-scale analysis showed significant deterioration for five of the 13 items. Multivariate logistic regression found that significant predictor of VFQ-25 composite score reduction was fewer laser burns (p = 0.002) while significant predictor of RetTSQ total score reduction was presence of hyperlipidaemia (p = 0.021). Conclusion: The use of vision-related quality of life and treatment satisfaction questionnaires in conjunction with clinical examination, appears to provide a more comprehensive overview of an individual's daily well-being following PRP. Laser treatment for diabetic retinopathy leads to deterioration of some of the patients' perceived VR-QOL and TS. Health-care providers should inform patients about their treatment options and together decide which therapeutic method is best for them.

Long-Term Retinal Neurovascular and Choroidal Changes After Panretinal Photocoagulation in Diabetic Retinopathy.

Purpose: To evaluate the long-term retinal microvascular, neural, and choroidal changes in the patients with severe nonproliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR) following panretinal photocoagulation (PRP).Methods: Forty-five eyes of 28 patients with treatment-naive severe NPDR and PDR were included and followed for 12 months after PRP. Microvascular and neural changes in the macular and peripapillary areas were assessed by using optical coherence tomography angiography. Subfoveal choroidal thickness (SFCT) was measured by using optical coherence tomography. A Linear mixed-effects model was used to highlight the differences for the variables after adjusting for sex, age, and axial length.Results: Compared to baseline, there were no statistical differences in the best corrected visual acuity (BCVA), macular and peripapillary vessel density (VD), and SFCT following PRP. Macular thickness significantly increased at 1 and 3–6 months after PRP (p < 0.05), while the peripapillary retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) thickness significantly increased at 1 month postoperatively (p < 0.01). Global loss volume and focal loss volume significantly decreased at the same time point (p < 0.05).Conclusion: The unchanged BCVA, VD, the thickness of RNFL and GCC, and SFCT during the 12-month follow-up period suggest that PRP may prevent the retinal neurovascular and choroidal damage.

Clinical study: Evaluation of the effect of topical nepafenac on central foveal thickness and visual acuity post panretinal photocoagulation in diabetic retinopathy

Objectives: To study the effect of topical nepafenac in patients with diabetic retinopathy following PRP in terms of Central foveal thickness (CFT) and Best corrected visual acuity(BCVA). Materials and Methods: This is a hospital based randomized control study conducted in Minto ophthalmic hospital, Regional institute of ophthalmology and Bowring and Lady Curzon hospital, from November 2018 to May 2020. Patients with proliferative diabetic retinopathy (PDR) without macular edema were subjected to PRP after detailed clinical evaluation and were divided into test and control groups. All the patients in two groups were matched based on: age, gender, type of diabetes, HBA1C levels and duration of type II diabetes. All patients underwent three sittings of PRP with a gap of one week interval between the sittings. Nepafenac eye (Nevanac, Alcon Laboratories Inc, Texas, USA) drops were used three time a day for a month followed by two time a day for three months in the test group and moxifloxacin eye drops (placebo)(moxicip, Cipla Ltd, India) three time a day for a month followed by two times for 3 months were used in the control group following PRP. Results: The patients in both test and control group were followed up at 1,2 and 4 months after PRP completion and the changes in CFT and BCVA were recorded. There was increase in CFT on each follow up visit in both test and control group. However increase in CFT in test group was less compared to control group which is statistically significant.(p=0.0001) There was worsening of BCVA in the test group was less compared to control group which is clinically significant but statisticially insignificant. Conclusion: Using topical Nepafenac eye drops following PRP for PDR is effective in reducing central foveal thickness and preventing the corresponding worsening of BCVA. Keywords: Panretinal Photocoagulation, OCT, Central Foveal Thickness, Nepafenac.

Long-Term Visual Function Effects of Pan-Retinal Photocoagulation in Diabetic Retinopathy and Its Impact in Real Life.

PurposeTo address the long-term visual function after bilateral pan-retinal photocoagulation (PRP) and its impact in real life, namely on visual field (VF) legal criteria to drive. To determine potential predictors related to clinical factors and treatment strategies.Patients and MethodsObservational cross-sectional study. Eyes from diabetic patients diagnosed with diabetic retinopathy who underwent bilateral PRP, with or without macular treatments and with visual acuity legal criteria for non-professional driving were randomly assigned. Main outcomes were: demographic and clinical data including best corrected visual acuity; binocular visual field (EBST-Esterman Binocular Suprathreshold Test, Humphrey analyzer3®); contrast sensitivity (CS-Metrovision-MonPack3®); light scattering in the retina (HD Analyzer, Visiometrics®).ResultsSeventy-one diabetic patients included (44 men and 27 women), with a mean age of 62.2±11.8 years. PRP was performed, on average, 9.7±6.9 years before the study. The average EBST Score was 85.8±17.0 and the average CS (2–5cpd) was 19.5±2.9 dB in photopic and 14.2±4.1 dB in mesopic conditions. Through a multivariate regression model, after adjusting to the clinical and demographic factors as possible confounders, we found that treatment factors associated with worse results were the use of Argon laser for the EBST Score, the very confluent PRP for the number of non-viewed points in the central 30°x20° of the EBST and the presence of macular treatments for the CS tests. According to Portuguese law, 79% (n=56) of patients had minimal EBST amplitudes for non-professional driving.ConclusionThe functional results achieved in our sample are compatible with an active life, allowing most of the patients included to overcome the requirements of Portuguese legislation for driving light vehicles, namely at the level of the binocular visual field. These results highlight the role of PRP in the treatment of diabetic retinopathy in an era with evolving less aggressive laser options.

Long-Term Structural Effects of Retinal Photocoagulation in Diabetic Retinopathy

Long-Term Structural Effects of Retinal Photocoagulation in Diabetic Retinopathy

Retinal vascular caliber changes after laser photocoagulation in diabetic retinopathy

BACKGROUND Diabetic retinopathy causes vascular dilatation caused by hypoxia, whereas oxygen tension improvement leads to retinal vessels narrowing. Given that laser photocoagulation aims to increase the oxygen tension in the retina, we hypothesized that the narrowing of vessel caliber after the treatment could be possibly demonstrated. This study aimed to assess the changes in the caliber of retinal vessels before and after laser photocoagulation in diabetic retinopathy.&#x0D; METHODS This research was a prospective cohort study on the treatment of diabetic retinopathy by laser photocoagulation, and it was conducted at Universitas Hasanuddin Hospital, Makassar, Indonesia between November 2017–April 2018. Retinal vascular caliber changes were analyzed before and 6–8 weeks after photocoagulation in 30 diabetic eyes. Central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) were measured using the vessel assessment and measurement platform software for images of the retina (VAMPIRE) manual annotation tool.&#x0D; RESULTS A significant decrease of CRVE was observed after laser photocoagulation (p&lt;0.001), but CRAE was not reduced significantly (p = 0.067). No difference was recorded between CRVE and CRAE post-laser photocoagulation (p = 0.14), implying a reduction in vein caliber toward normal in the treated eyes.&#x0D; CONCLUSIONS Laser photocoagulation decreases the CRVE in diabetic retinopathy despite the absence of changes in the grade of diabetic retinopathy.

Longitudinal analysis of subfoveal choroidal thickness after panretinal laser photocoagulation in diabetic retinopathy using swept-source optical coherence tomography

Purpose: To describe the central three-dimensional (3D) thickness profile of the macula (CMT) and the subfoveal choroidal region (SFCT) in diabetic retinopathy (DR) following panretinal laser photocoagulation (PRP) using swept-source optical coherence tomography (SS-OCT). Methods: A prospective observational study including 17 eyes with proliferative DR (PDR) and 27 eyes with severe nonproliferative DR (sNPDR)] for whom PRP was done. All subjects received SS-OCT imaging before and 3 months after PRP (POM#3). SFCT and CMT changes were analysed at both visits. Intraclass Correlation Coefficients (ICC) and Coefficients of Variation (COV) were used to test the accuracy of thickness data. Results: SFCT has thinned from 233 ± 54 µm before PRP treatment to 216 ± 51 µm 3 months later (p < 0.001). Likewise, CMT declined at POM#3 as compared to pre-PRP status (p<0.001). SFCT was thinner in PDR before and at POM#3 (p<0.05) than sNPDR; whereas, no significant difference was observed in CMT between both groups in the two visits. No significant changes were found between groups in SFCT and CMT at POM#3. Regarding reliability, ICCSFCT=0.98 and ICCCMT=0.99. The COVs for CMT and SFCT were 5.03% and 5.91%, respectively. Conclusion: The mean SFCT and CMT decreased 3 months after PRP. We also reported reliability of SFCT measurements in DR using SS-OCT. Abbreviations: SS = Swept-Source, TD = time domain, SD = spectral domain, FD = Fourier-domain, 3D = three-dimensional, 2D = two-dimensional.

Changes in retinal nerve fiber layer thickness after panretinal photocoagulation in diabetic retinopathy

Context: Panretinal photocoagulation (PRP) is the gold standard treatment for high risk proliferative diabetic retinopathy. Aim: The evaluation of peripapillary retinal nerve fiber layer (RNFL) thickness changes in eyes undergoing PRP by optical coherence tomography. Materials and Methods: RNFL thickness was measured before PRP, then after PRP by 1, 3, and 6 months, respectively. Results: Mean peripapillary RNFL thickness increased significantly 1 month after P (P = 0.001), then showed insignificant decrease at 3 months' post-PRP (P = 0.1), then it showed significant decrease at 6 months (P = 0.0001) compared to baseline. Conclusions: PRP should be used with a great caution with least number of shots to avoid excessive damage to inner retinal layers.

Single session of pattern scanning laser versus multiple sessions of conventional laser for panretinal photocoagulation in diabetic retinopathy: Efficacy, safety and painfulness

PurposeTo evaluate the clinical efficiency, safety and painfulness of retinal laser photocoagulation employing a pattern scanning laser system Pascal given in a single-session versus conventional laser multiple-session treatment of the same patient with diabetic retinopathy during 12-month follow-up.MethodsThe cohort included 60 eyes in 30 patients treated at the Ophthalmology Clinic, Faculty Hospital Ostrava, from 2008 to 2013. Panretinal laser coagulation was performed on one eye using the multispot panretinal photocoagulation given in a single-session system Pascal (OptiMedica, Santa Clara, California). On the other eye laser treatment was carried out by the classic conventional multiple-session method.ResultsThe performance of Pascal panretinal laser coagulation was evaluated as significantly less painful (visual scale of pain was 3.28 ± 1.9) than the performance of conventional photocoagulation (visual scale of pain was 3.93 ± 1.88) with similar efficiency. Distribution of progression of diabetic retinopathy in individual patients was very similar in both groups under comparison, and was strictly paired in 24 of the 30 patients at the end of 1-year follow-up.ConclusionLaser photocoagulation of the retina with the use of short impulse durations and patterns in patients with diabetic retinopathy given in one session possesses similar efficiency to that of conventional retinal photocoagulation in multiple sessions. The single session treatment is also better tolerated by patients and in addition to this, it shortens the performance of the whole therapy, which potentially saves considerable funds of all subjects participating in the process of treatment.Trial registrationClinicalTrials.gov NCT03672656.

Quantitative analysis of visual field loss after 577 nm krypton pan-retinal photocoagulation for diabetic retinopathy

Objective To observe the visual field loss after 577 nm krypton pan-retinal photocoagulation (PRP) in the treatment of diabetic retinopathy (DR). Methods A prospective clinical studies. Forty-six eyes of 26 patients with proliferative DR (PDR) and severe non-proliferative DR (NPDR) diagnosed by clinical examination from No. 306 Hospital of PLA during January 2014 and December 2015 were included in this study. Among them, 21 eyes of NPDR and 20 eyes of PDR; 13 eyes with diabetic macular edema (DME) (DME group) and 28 eyes without DME (non-DME group). All eyes underwent best corrected visual acuity (BCVA), fundus color photography, fundus fluorescein angiography (FFA) and optical coherence tomography (SD-OCT) examinations. The visual field index (VFI) and visual field mean defect (MD) values were recorded by Humphrey-7401 automatic visual field examination (center 30° visual field). The BCVA of DR eyes was 0.81±0.28; the VFI and MD values were (89.8±8.4)% and −7.5±3.85 dB, respectively. The BCVA of the eyes in the without DME group and DME group were 0.92±0.20 and 0.57±0.27, the VFI were (90.86±7.86)% and(87.46±9.41)%, the MD values were −6.86±3.43 and 8.87±4.48 dB. PRP was performed on eyes using 577 nm krypton laser. The changes of VFI, MD and BCVA were observed at 1, 3, and 6 months after treatment. Results Compared with before treatment, the VFI of DR eyes decreased by 12.0%, 12.3% and 14.8% (t=7.423, 4.549, 4.79; P 0.05) and MD value (t=−0.560, −0.337; P>0.05) at different time points after treatment. Compared with before treatment, the BCVA was significantly decreased in DR eyes at 1 month after treatment, the difference was statistically significant (t=2.871, P 0.05) and MD values (t=1.582, 0.776, 0.927, 1.098; P>0.05) between the two groups. Conclusion The range of 30° visual field loss is about 12%-14.8% after 577 nm krypton laser PRP for DR. VFI and MD can quantitatively analyze the and extent of visual field loss after PRP treatment. Key words: Diabetic retinopathy/therapy; Laser coagulation/adverse effects; Visual fields

Foveal Chorioretinal Anastomosis Secondary to Macular Focal Photocoagulation in Diabetic Retinopathy

Foveal Chorioretinal Anastomosis Secondary to Macular Focal Photocoagulation in Diabetic Retinopathy

Efficacy of vitrectomy combined with selective retinal photocoagulation for diabetic retinopathy

Objective To observe the efficacy of pars plana vitrectomy (PPV) combined with selective retinal photocoagulation (SRP) in the treatment of proliferative diabetic retinopathy (PDR) with vitreous hemorrhage. Methods Two hundred eyes of 190 patients with PDR and vitreous hemorrhage were enrolled in this study.All patients were treated with 23-gauge PPV combined with retinal photocoagulation and intravitreal injection of Lucentis and triamcinolone acetonide.All patients were divided randomly into two groups: the contral group, 108 eyes of 102 cases, received panretinal photocoagulation(PRP) during surgery and the observation group, 92 eyes of 88 cases, received SRP during surgery. All patients were followed up for 6 months.The effect were compared between the two groups. Results BCVA of observation group was better than that of contral group at 1 week, 1 month and 3 months after surgery.The difference was statistically significant(P=0.000). The difference in BCVA was not statistically significant between the two groups at 6 months after surgery(P=0.094). The central macular thickness(CMT) of observation group was lower than that of contral group at 1 week and 1 month after surgery, the difference was statistically significant(P=0.000). The difference was not statistically significant at 3 months after surgery between the two groups(P=0.349). The number of times of retinal photocoagulation in observation group was more than that in contral group.The difference was statistically significant(P=0.000). The incidence of recurrent vitreous hemorrhage and neovascular glaucoma in observation group were higher than those in contral group.The difference were not statistically significant(P=0.526, 0.470). Conclusion Under the auxiliary of anti-vacular endothelial growth factor and triamcinoloneacetonide, microincision vitrectomy with SRP is better than microincision vitrectomy with PRP to treat patients with vitreous hemorrhage and PDR in reducing postoperative macular edema and improve the visual acuity. Key words: Retinopathy, diabetic, proliferative; Vitreous hemorrhage; Vitrectomy, 23-gauge; Photocoagulation, retinal, selective, pan

What do Cochrane systematic reviews say about diabetic retinopathy?

Diabetic retinopathy is a disease caused by increased permeability of retinal vessels. Its incidence and prevalence have been increasing due to urbanization, greater life expectancy and the habits of modern life. Its onset is insidious and it may lead to blindness in 75% of individuals who have been diabetic for more than 20 years. The aim here was to evaluate the evidence from Cochrane systematic reviews on interventions relating to diabetic retinopathy. Review of systematic reviews, conducted at Cochrane Brazil. We included Cochrane systematic reviews on interventions relating to diabetic retinopathy. Two researchers evaluated the inclusion criteria, summarized the reviews and presented the results narratively. Ten reviews met the inclusion criteria. They showed some evidence of benefits from: (a) photocoagulation for diabetic retinopathy; (b) strict glucose and pressure control for postponing the onset of retinopathy; (c) antiangiogenic drugs for macular edema (high-quality evidence); (d) anti-vascular endothelial growth factor agents for proliferative diabetic retinopathy (very low to low-quality evidence); and (e) intravitreal injection or surgical implantation for treating persistent or refractory macular edema. However, blood pressure control seems to have no benefit after the onset of retinopathy. Only a few options are likely to be effective for treating diabetic retinopathy. These include photocoagulation and anti-vascular endothelial growth factor agents. Strict glucose and pressure control seem to postpone the onset of retinopathy. For macular edema, antiangiogenic drugs, intravitreal injection and surgical implantation seem to have some benefit.

Ruptured Retinal Arterial Macroaneurysm after Panretinal Photocoagulation for Diabetic Retinopathy

Ruptured Retinal Arterial Macroaneurysm after Panretinal Photocoagulation for Diabetic Retinopathy

Retinal Nerve Fibre Layer Thickness Changes after Pan-Retinal Photocoagulation in Diabetic Retinopathy

Diabetic retinopathy is a disease involving microangiopathic changes in response to chronic hyperglycaemia and pan retinal photocoagulation (PRP) is currently the mainstay of treatment for proliferative retinopathy. In the present study, we evaluated the effect of pan retinal photocoagulation (PRP) on retinal nerve fibre layer (RNFL) thickness in patients with diabetic retinopathy using optical coherence tomography (OCT). This was a prospective longitudinal study. Patients with Type 2 diabetes mellitus with proliferative diabetic retinopathy (PDR) or very severe non-(N)PDR requiring laser treatment were included in the study. PRP was performed by a single trained personnel. Peripapillary RNFL located 3.4 mm around the optic disc was evaluated using time-domain OCT. Examination was performed before treatment, and 2 and 4 months after laser treatment. In total, 39 subjects (39 eyes) were recruited into this study. Twenty-nine patients had PDR and 10 had very severe NPDR. Mean age was 54.97 ± 8.38 years. Male and female genders were almost equally distributed with 18 males and 21 females. Median thickness of average RNFL at baseline was 108.8 um (interquartile range [IQR] 35.3). At two months post-procedure, average RNFL thickness significantly increased to 117.4 (IQR 28.6; P = 0.006). Although, other quadrants revealed a similar trend of increasing thickness at two months but it was not significant. At 4 months post-laser treatment, RNFL thickness in all quadrants reduced to baseline levels with insignificant changes of thickness compared to prior to laser treatment. There was also no significant association between changes in RNFL thickness and HbA1c levels (P = 0.77). In conclusion, PRP causes transient thickening of the RNFL which recovers within 4 months post-laser treatment. At the same time, poor sugar control has no direct influence on the RNFL changes after PRP.

Evaluation of Effectivity of Laser Photocoagulation in Diabetic Retinopathy

Evaluation of Effectivity of Laser Photocoagulation in Diabetic Retinopathy

Retinal oximetry in diabetic retinopathy

AbstractBackground: Diabetic retinopathy is accompanied by disturbances in retinal blood flow, but the consequent changes in oxygenation of the retinal tissue have not been studied in detail. The advent of retinal oximetry for assessing the oxygen saturation in retinal vessels has enabled the study of changes in retinal oxygen saturation during the progression and after treatment of the disease. Methods: 71 patients with proliferative diabetic retinopathy and 149 with diabetic maculopathy were subjected to retinal oximetry of the larger retinal arterioles and venules before, immediately after and three months after retinal photocoagulation. Results: Before treatment the oxygen saturation was significantly increased, both in patients with proliferative diabetic retinopathy and diabetic maculopathy. The oxygen saturation was unchanged immediately after treatment, but had further increased three months after treatment. Conclusion: Disturbances in retinal oxygen saturation in diabetic patients are complex and may be due to changes in blood flow, oxygen extraction and regional variations in blood flow. Retinal photocoagulation in diabetic retinopathy does not exert its effect by normalizing retinal oxygenation.