Laser Photocoagulation For Diabetic Retinopathy Research Articles

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.
 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.
 RESULTS A significant decrease of CRVE was observed after laser photocoagulation (p<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.
 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.

Evaluation of Effectivity of Laser Photocoagulation in Diabetic Retinopathy

Evaluation of Effectivity of Laser Photocoagulation in Diabetic Retinopathy

New Frontiers in Selective Retinal Lasers

Retinal laser photocoagulation was first described over 50 years ago and remains the standard of care for many retinal diseases. Conventional retinal laser photocoagulation for diabetic retinopathy, retinal vascular diseases, and retinal tears is typically performed with a continuous wave laser in the green, yellow, or red range, primarily at 514 or 532 nanometers (nm), pulse duration of 100 to 200 milliseconds (ms), spot size from 100 to 500 micrometers (um), and laser power to achieve the clinical endpoint, typically around 100 to 750 milliwatts (mW). Laser therapy is typically empirically titrated to a visible clinical effect of greyish whitening of the retina, which corresponds to photoreceptors necrosis and inner retinal damage.

Laser photocoagulation for proliferative diabetic retinopathy.

Laser photocoagulation for proliferative diabetic retinopathy.

Diabetic retinopathy treated with laser photocoagulation and the indirect effect on glycaemic control.

Purpose. To identify any possible relation between glycaemic control and previous laser photocoagulation for diabetic retinopathy. Methods. Seventy-two patients with diabetes were included in the study and were separated into 2 groups according to previous treatment (group A) or not (group B) with argon laser photocoagulation. Glycaemic control was estimated by measuring blood levels of HbA1c in four consecutive measurements. Results. Blood levels of HbA1c in group A were significantly lower 3, 6, and 12 months after laser treatment as compared to blood levels of HbA1c before laser treatment (7.1 ± 0.4% versus 7.6 ± 0.9%, 7.2 ± 0.2% versus 7.6 ± 0.9%, and 7.1 ± 0.2% versus 7.6 ± 0.9%, resp., all P < 0.05). Blood levels of HbA1c in group B did not differ significantly in four consecutive measurements. Conclusion. Our results suggest that we should anticipate a better glycaemic control in cases of patients with diabetes previously treated with laser photocoagulation.

Multi-wavelength laser photocoagulation for diabetic retinopathy

Objective To study the therapeutic effect of multi-wavelength laser photocoagulation for diabetic retinopathy.Methods Thirty cases (52 eyes) of diabetic retinopathy confirmed by results of fundus fluorescence angiography and optical coherence tomography were treated by multi-wavelength laser photocoagulation which included red light,green light and yellow light laser.Macular grid photocoagulation was also performed on patients combined with macular edema.Results Follow up was 6 months.The visual acuities were improved in 35 eyes,no change in 14 eyes and decreased in 3 eyes which were caused by macular edema.The mean macular thicknesses shown by optic coherence tomography were (430.35 ±98.53) μm before treatment and (178.48 ± 42.56) μm at 6 months after laser treatment.Conclusion Multi-wavelength laser photocoagulation in the management of diabetic retinopathy is effective which can improve patients' visual function. Key words: Retinopathy, diabetic; Laser, multi-wavelength; Photocoagulation, laser

English

PURPOSE: To evaluate the visual outcome after laser photocoagulation in diabetic retinopathy. METHODS: One eye each of 100 patients were enrolled in our prospective, randomized, clinical trial study with proliferative diabetic retinopathy/ maculopathy were assessed for visual outcome after treating them with laser photocoagulation. RESULTS: We observed that 62 (62%) patients showed improvement by 1 or more lines on Snell’s chart, 26 (26%) deteriorated from baseline visual acuity. The overall mean improved was 0.56 lines on Snell’s chart that is clinically significant. CONCLUSION: The results of present collection of hundred patients show a favourable influence of photocoagulation on the improvement and preservation of baseline visual acuity. Timely focal and grid laser photocoagulation helps in improving and stabilizing the visual acuity in patients with diabetic macular edema.

The impact of phacoemulsification cataract surgery on eyes previously treated by laser photocoagulation for diabetic retinopathy

to evaluate the evolution of diabetic retinopathy (DR) after cataract surgery on eyes previously treated by photocoagulation for DR. The compensation of glycaemia (glycosylated haemoglobin, HbA1c) and prevalence of attendant diseases (hypertension, ischemic heart disease and alteration of lipid metabolisms) were evaluated. Forty eyes (40 patients) were evaluated, of which ten (25 %) eyes with DR were treated without laser photocoagulation (LK), and 30 (75 %) eyes were previously treated by LK. Two criteria for evaluating the stabilisation were used, particularly the best corrected visual acuity (BCVA) and the necessity of additional laser photocoagulation. As many as 100 % of eyes without LK and 86.7 % of eyes with LK had BCVA improved on the first day after surgery (p ≤ 0.05). The BCVA of 0.5 or better was achieved in 31 eyes (77.5 %). The mean level of HbA1c in group without LK was 7.09 ± 1.21 %; in group after LK it was 7.36 ± 1.64 %. The mean level of HbA1c in the group with stable BCVA was 7.14 ± 0.46 % and the duration of DM was 18.6 ± 2.93 years. HbA1c, in group of eyes with worsened BCVA, was 7.86 ± 2.23 %, and the duration of DM was 21.0 ± 8.54 years. HbA1c in the group of stable eyes (without LK after surgery) was 6.71 ± 0.1 %, and the duration of DM was 17.84 ± 8.97 years. HbA1c, in group, where additional LK was applied, was 7.56 ± 0.69 %, and the duration of DM was 19.54 ± 3.26 years. The difference in levels of HbA1c was statistically significant (p ≤ 0.1). The prevalence of attendant disease was highest in the group of eyes with worsened BCVA and necessity of additional LK. The results of study confirm an improvement in BCVA after cataract surgery by phacoemulsification in the most of patients. Better stabilisation of glycaemia levels and lower frequency of internal diseases were in group with stable BCVA and without necessity of additional LK after cataract surgery (Tab. 3, Fig. 1, Ref. 28).

Minimiza el carvedilol los requerimientos de fotocoagulación láser en la retinopatía diabética

Minimiza el carvedilol los requerimientos de fotocoagulación láser en la retinopatía diabética

Giant retinal pigment epithelial tear after laser photocoagulation for diabetic retinopathy

A 62-year-old man, who underwent focal laser photocoagulation in the left eye (OS) for diabetic retinopathy 2 years previously, complained of metamorphopsia OS. The left fundus had a semilunar retinal...

Factors affecting focal/grid laser photocoagulation in diabetic retinopathy

Focal/grid laser photocoagulation is associated with a reduction in the risk of moderate vision loss. The efficacy of focal/grid laser photocoagulation is dependent on a number of different factors, such as baseline visual acuity. However, the relationship between efficacy of focal/grid laser photocoagulation and other factors, such as the different types of diabetic macular edema, are still unclear and further clarity needs to be ascertained from carefully designed trials in the future. Since focal/grid laser photocoagulation often requires repeated treatments and each treatment carries additional risks of side effects, detailed knowledge of which specific characteristics carry better prognostic value would be essential in the assessment of benefit-to-risk ratio in the management of patients with diabetic macular edema. The purpose of this article is to review the literature on factors affecting efficacy and limitations of focal/grid laser photocoagulation treatment in patients with diabetic macular edema.

Optical coherence tomography and vessel diameter changes after intravitreal bevacizumab in diabetic macular oedema

To assess the effect of intravitreal bevacizumab on diabetic macular oedema (DMO) and retinal vessel calibres. We performed a consecutive case series study in which 10 consecutive eyes with diffuse DMO, two of which had not previously been treated, received an intravitreal injection of bevacizumab 1 mg, which was followed by two more injections at 6-week intervals. Fundus photography and optical coherence tomography (OCT) were carried out at baseline immediately before injection and at 1, 2.5 and 4 months after the first injection. Outcome measures were best corrected visual acuity (BCVA) in Early Treatment Diabetic Retinopathy Study letters, macular volume, foveal subfield thickness and vessel diameter measurement. Intravitreal administration of bevacizumab was followed by a mean increase in BCVA of 7.3 +/- 17 (mean +/- standard deviation) letters between baseline and month 4, which was 1 month after the last injection (p < 0.0001). This was accompanied by a reduction in mean macular volume from 9.90 +/- 1.9 mm(3) to 8.96 +/- 2.4 mm(3) (p = 0.002) and in foveal subfield thickness from 447 +/- 117 microm to 388 +/- 117 microm (p = 0.03). Two eyes with early proliferative diabetic retinopathy lost all signs of proliferation without any evidence of fibrosis. Although there was a trend towards vasoconstriction, the changes in vessel diameters (arteries and veins) after 4 months of intravitreal Avastin injection were not statistically significant (p = 0.9 and p = 0.17, respectively). Foveal thickness in non-injected fellow eyes with DMO changed from 428 +/- 153 microm at baseline to 383 +/- 151 microm at 4 months (p = 0.1), which did not reach statistical significance. Intravitreal bevacizumab 1 mg every 6 weeks was followed by a moderate reduction in DMO without normalization of foveal and macular thickness. Our observations suggest that a larger study where patients are examined sooner after injection is needed to elucidate the potential relationship between changes in retinal vessel diameters and thickness changes in DMO.

Tonic Pupil as the Presenting Sign of Relapsed Acute Myeloid Leukemia

A 23-year-old woman complained of photophobia, lacrimation, and redness of the left eye of 1 week's duration and a dilated left pupil. Acute myeloid leukemia (AML) had been diagnosed 5 years earlier and treated with a stem cell transplant. She had developed graft vs host disease (GVHD) affecting her skin and had undergone psoralen plus UVA (PUVA) treatment. The AML had been in remission for 3 years before her ophthalmic visit. Medications included acyclovir, fluconazole, penicillin, cyclosporine, and mycophenolate. Systemic corticosteroid treatment had recently been discontinued. Best-corrected visual acuities were 20/20 in the right eye and 20/40 in the left eye, improving to 20/30 with pinhole. In the left eye, the palpebral fissure was slightly narrow but with normal levator function, the tear break-up time was reduced, and there was punctate staining of the cornea. The pupils measured 2 mm in the right eye and 4 mm in the left eye in minimal illumination. On bright light stimulation with the indirect ophthalmoscope light, the right pupil constricted to 1 mm and the left remained at 4 mm. After stimulation by a near target the left pupil also constricted to 1 mm. The left eye showed vermiform movements of the iris on slit lamp examination. Dilute pilocarpine (0.125%) was then instilled in both eyes. After this both pupils measured 2 mm, demonstrating hypersensitivity of the left pupil. She was orthophoric and had a full range of ocular movements. Posterior subcapsular lens opacities were present in both eyes. Ophthalmoscopy was normal. The punctuate epitheliopathy of the cornea was attributed to GVHD and the cataracts to the use of systemic corticosteroids. Left tonic pupil was diagnosed. Lubricants were prescribed for the epitheliopathy. Two days later, she returned complaining of blurred vision. Best-corrected visual acuities were 20/80 in the right eye and 20/40 in the left eye. There was no change in the anterior segment findings of either eye. Ophthalmoscopy showed localized elevation of the retina in the macular region in both eyes. B scan ultrasound showed thickening and irregular elevations of the choroid in both eyes (Fig. 1). Fluorescein angiography showed pinpoint areas of hyperfluorescence of increasing brightness in the macular region of both eyes.FIG. 1: B scan ultrasound of the left eye shows thickening and irregularity of the choroid (arrowhead) and overlying serous retinal detachment.Blood tests showed an elevated white cell count, indicating relapse of leukemia. Brain and orbit MRI showed only faint mucosal thickening of the sinuses. Chemotherapy was begun. The leukemia could not be controlled, and she subsequently died of systemic complications. Tonic pupil can be caused by Adie syndrome, systemic neuropathic diseases, or local lesions (1). Adie syndrome is characterized by tonic pupil and disturbance of deep tendon reflexes without evidence of local ocular or orbital disease or generalized peripheral or autonomic system dysfunction. Orbito-ocular causes of tonic pupil include inflammation, infection, or infiltration that affects ciliary ganglion or the ciliary nerves in the retrobulbar region or in the suprachoroidal space. Tonic pupil has been reported in siderosis caused by retained intraocular foreign body (2); injury to the final cholinergic fibers within the suprachoroidal space was postulated as the likely pathologic mechanism. Postganglionic denervation by damage within the suprachoroidal space has also been reported with retinal detachment surgery using explants (3) and after laser photocoagulation for diabetic retinopathy (4). Leukemia can cause tonic pupil by direct infiltration of the orbit or the choroid. However, postganglionic nerve injury at the level of the eye in choroidal cancer has been reported only once (5). In our patient, there was no imaging evidence of orbital infiltration at presentation. The ultrasound study showed extensive choroidal thickening and irregularity. The fluorescein evidence of pinpoint leaks and serous retinal detachment indirectly indicated dysfunction of the retinal pigment epithelium. A similar phenomenon caused by choroidal infiltration has been reported (6). Hence it is likely that the damage to the ciliary nerves occurred at the suprachoroidal level. Mandagere R. Vishwanath, FRCSEd Stephen J. Charles, MA, MD, FRCOphth Manchester Royal Eye Hospital Manchester, United Kingdom [email protected]

Anterior chamber depth and intraocular pressure following panretinal argon laser photocoagulation for diabetic retinopathy

Anterior chamber depth and intraocular pressure following panretinal argon laser photocoagulation for diabetic retinopathy

Complications of Diabetes Mellitus

Observational and clinical trial data show a clear relationship between the degree of hyperglycemia and the risk to develop diabetic retinopathy, diabetic nephropathy and diabetic neuropathy. Intervention trials comparing two different levels of glycemic control demonstrate that for every 1% reduction in HbA 1c , there is approximately a 25-30% reduction in these complications of diabetes. Furthermore, data from the Diabetes Control and Complications Trial show that the effects of early intensive therapy are durable for periods of at least 7 years. Early detection of the complications permits early intervention. Furthermore, other specific intervention strategies may also reduce the r isk for progression of complications. These strategies include laser photocoagulation for diabetic retinopathy (proliferative retinopathy and clinically significant macular edema), BP control and modulation of the renin-angiotensinaldosterone system for diabetic nephropathy and unloading devices for diabetic neuropathy. Other potential strategies to reduce the risk for onset and progression of these complications include such approaches as lipid lowering, aldose reductase inhibition and protein kinase C inhibition.

West African crystalline maculopathy

Objective To report new observations in West African crystalline maculopathy. Design Retrospective, observational case series. Participants Three patients drawn from a private retina practice. Methods Review of clinical charts and photographic studies. Main outcome measures Distribution of intraretinal crystals and changes after laser photocoagulation, and history of ingesting foods typical in a West African diet but atypical for an American diet. Results All patients were older than 50 years, had diabetic retinopathy, ate green vegetables not found in American diets, and showed no deleterious effects of the crystals. Kola nut ingestion in 2 patients was remote and sparse, and was unknown in a third patient. The first 2 affected patients originating outside the Ibo tribe of Nigeria are reported. The pattern of retinal crystals can be changed, and the quantity of crystals reduced, by laser photocoagulation of associated diabetic retinopathy. Conclusions West African crystalline retinopathy is distinguishable from other causes of crystalline retinopathy. It may reflect a component of the West African diet, seems to have diabetic retinopathy as a promoting factor via breakdown of the blood–retina barrier, and can be modified by laser photocoagulation of diabetic retinopathy. Increased awareness of the condition will allow physicians seeing West African immigrants to make the diagnosis and treat the patients appropriately.

Surgical removal of subfoveal iatrogenic choroidal neovascular membranes

Objective To present the cases of two patients with laser-induced iatrogenic subfoveal choroidal neovascular membranes (CNVMs) who underwent surgical removal of the membranes with favorable outcomes. Design Interventional case reports. Participants Two patients with iatrogenic subfoveal CNVM. One case developed after laser treatment for macular edema due to branch retinal vein occlusion, and the second case developed after focal laser photocoagulation for diabetic retinopathy. Intervention Surgical removal by pars plana vitrectomy. Main outcome measures Visual acuity, scotoma, retinal examination with fundus photography, and fluorescein angiography before surgery and during the postoperative period. Results Both patients underwent surgical removal after progression of the membrane with severe visual loss of 20/200 was noted. At present follow-up, there is a significant improvement in visual acuity and a reduction in the size of the scotoma. No recurrence of CNVM is noted. Conclusion Both patients with laser-induced iatrogenic subfoveal CNVM achieved a good visual outcome after surgical removal of the membrane. The reasons for a good surgical result are thought to be twofold. First, the origin of the CNVM is extrafoveal at the site of laser application. The chance for foveal cone cell damage during the surgery is reduced. Second, the degree of cellular destruction in iatrogenic CNVM is usually focal without extensive retinal photoreceptor cell and retinal pigment epithelial damage. Therefore, a better chance of postoperative visual recovery is anticipated.

Exudative age-related macular degeneration in patients with diabetic retinopathy and its relation to retinal laser photocoagulation.

To study the relationship between exudative age-related macular degeneration and diabetic retinopathy and assess the influence of retinal laser photocoagulation for diabetic retinopathy on the occurrence of exudative age-related macular degeneration. Two groups, one of diabetic retinopathy patients treated with laser and the other of non-laser-treated diabetic retinopathy patients, were studied by means of fundoscopy and fluorescein angiography for the presence of exudative age-related macular degeneration. Exudative age-related macular degeneration was not observed in 431 patients treated with laser photocoagulation, and was diagnosed in 3.3% of 151 non-laser-treated patients. Patients treated by laser photocoagulation for diabetic retinopathy are less prone to develop the exudative form of age-related macular degeneration.

Ciliary Body and Choroidal Detachment after Laser Photocoagulation for Diabetic Retinopathy: A High-frequency Ultrasound Study

The purpose of the study is to clarify the manifestation of the ciliary body after retinal photocoagulation for diabetic retinopathy. Ultrasound biomicroscopy (UBM) was applied to obtain the tomographic features of the anterior ocular segment. Twenty-one eyes of 17 consecutive patients with diabetic retinopathy were included in this study. These eyes were treated by panretinal photocoagulation divided in four sessions. In the first session, the nasal quadrant of the fundus was treated with argon or dye (590 nm) laser totaling 208 to 331 spots per eye. The eyes were examined by UBM before, immediately after, 3, and 7 days after the first session of photocoagulation. Three days after photocoagulation, ciliochoroidal detachment was observed in 19 eyes (90%). The detachment was present along the whole circumference. The ciliary detachment was most prominent in the pars plana in 19 eyes and extended to the pars plicata in 9 eyes. It spontaneously had disappeared 7 days after photocoagulation. Ciliochoroidal detachment was a very frequent feature after sector photocoagulation in diabetic eyes. Although this complication was asymptomatic and transient so far, this potential hazard merits due attention in the planning of panretinal photocoagulation in diabetic eyes.