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Research Article | DOI: https://doi.org/10.31579/2692-9406/162
1 Professor in Mansoura Ophthalmic Center, Faculty of Medicine, Mansoura University.
2 Lecture in Mansoura Ophthalmic Center, Faculty of Medicine, Mansoura University.
*Corresponding Author: Mona Abdel kader, Professor in Mansoura Ophthalmic Center, Faculty of Medicine, Mansoura University.
Citation: Mona Abdel kader, Ayman Fawzy, (2023),Triamacinolone Alone Versus Triamacinolone with Laser in Diabetic Macular Odema, J. Biomedical Research and Clinical Reviews. 8(4); DOI:10.31579/2692-9406/162
Copyright: © 2023, Mona Abdel kader. this is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Received: 24 August 2023 | Accepted: 01 September 2023 | Published: 08 September 2023
Keywords: ERG & OCT of DM
Background:Macular oedema is responsible for a significant decrease of vision in this population. Aim of the study is to assess retinal function by multifocal electroretinography (MF-ERG) in eyes with diabetic macular edema (DME) after intravitreal triamcinolone acetonide (IVTA) injection and to compare the effect of IVTA alone and after its combination with argon laser photocoagulation.
Methods: The study included eighty patients (120 eyes), divided into two groups. Group 1 included sixty eyes (60) of forty patients (40) with DME treated with triamcinolone acetonide injection alone, group 2 (laser group) included another sixty eyes (60) of forty patients (40) with DME treated with triamcinolone acetonide injection followed by argon laser photocoagulation (after 3 week). The response to treatment was monitored functionally by visual acuity measurement and MF-ERG and anatomically by foveal thickness measured by optical coherence tomography (OCT). The changes in functional and morphometric parameters were followed at 1 week and 1, 2, 3,6 months.
Results:Visual acuity and MF-ERG values increased after intravitreal triamcinolone acetonide injection. There was statistically significant increase in mean P1 amplitude compared with pretreatment. The mean P1 peak latencies were shortener. There were also statistically significant decreases in the mean foveal thickness after treatment. In group 1, there was deterioration of the initial improvement that started after 2 months from IVTA while in group 2, there was more stability of the initial improvement.
Conclusion: IVTA injection causes transient improvement of macular function and decreases of retinal thickness in diabetic patients. This study suggests the combination of IVTA, and argon laser photocoagulation causes more permanent improvement. Argon laser photocoagulation effectively maintains improvement occurring after IVTA and reduces recurrent DME after IVTA.
Macular oedema affects approximately 29% of diabetic patients with disease duration of 20 years or more and is responsible for a significant decrease of vision in this population. [1]
The Early Treatment Diabetic Retinopathy Study (ETDRS) demonstrated a significant benefit of focal laser photocoagulation for the treatment of clinically significant macular oedema. [2] However, eyes with diffuse diabetic macular edema carry a particularly poor prognosis despite laser photocoagulation. In the ETDRS, only 17% of the eyes had an improvement of visual acuity (V.A) and less than 3% had a visual improvement of [3] or more ETDRS lines.2 Laser photocoagulation is at best supportive rather than curative [2-3], prompting interest for alternative therapeutic approaches.
Intravitreal administration of triamcinolone acetonide has provided the ophthalmologist with an extra tool for the treatment of eyes with diabetic oedema. [4-5]
Triamcinolone acetonide, has been proposed to decrease macular oedema6, the probable mechanisms are increase in tight-junction protein, which diminish vessel leakage by a local vasoconstrictive effect, [7-8] and angiostatic properties through inhibition of vascular endothelial growth factor (VEGF).[9]
IVTA is reported to generate favorable results in the treatment of DME, however the chief limitation of IVTA is the recurrence of DME which develops after a relatively short duration of action. Although repeated administration of IVTA might be an option. Yet, repeated IVTA may potentiate the toxicity of the intraocular corticoid as elevation of intraocular pressure [10], cataractogensis [11] and endophthalmitis.[12]
The aims of this study are to assess macular function by MF-ERG and foveal thickness in eyes with diabetic macular oedema after IVTA injection and to determine whether macular argon laser photocoagulation after IVTA might be helpful in the maintenance of improvement after IVTA or not.
Patients and Methods:
This study was carried out on patients attending the outpatient's clinic of Mansoura Ophthalmic Center during the period from December 2012 to February 2014. This study included one hundred and twenty eyes of eighty patients with diabetic macular edema with no sign of vitreo-macular traction on either biomicroscopy or Optical Coherence Tomography (OCT). The patients were divided into two groups :Group 1 included sixty eyes (60) of forty patients (40) with DME treated with triamcinolone acetonide injection alone, group 2 (laser group) included another sixty eyes (60) of forty patients (40) with DME treated with triamcinolone acetonide injection followed by argon laser photocoagulation (after 3 week).The determination of group for the individual was randomized (dependent on last digit of hospital ID number .If it was an even number the patient was located in group 1, if it was an odd number ,the patient was allocated into group 2.
Macular oedema was defined by a zone or zones of retinal thickening one disc area or larger at any part within one disc diameter of the center of the macula on biomicroscopy and, by diffuse fluorescein leakage involving most of the macular area on fluoresein angiography or/ and areas of pooling of flourscein dye within two disc diameters at the center of the macula in cystoid macular edema.[13] Another criterion involved significant reduction in the reflectivity of the outer layer and/ or subfoveal collection on OCT or cavities of low reflectivity in posterior retinal layers or full retinal thickness with tiny walls in cystoid macular edema.[13] Central macular thickness had to be more than 300µm(normal 170±18µm).[13] Patients were thoroughly informed about the injection procedure, postoperative results and possible complications and written consents were taken from all patients. All tests were carried out in accordance with the tenets of the Declaration Of Helsinki(1989) of the world medical association. The study was approved by Mansoura University Hospital trust ethics committee
Exclusion Criteria: it included patients who previously received intravitreal injection either triamcinolone or bevacizumab, those with evidence of macular ischaemia, epiretinal membranes or vitreo-retinal traction, patients with past or current history of glaucoma. patients who had undergone cataract surgery or vitre-retinal surgery and patients with renal insufficiency. other ophthalmic disorders associated with macular oedema, such as uveitis and branch or central retinal vein occlusion
Pre-Injection Evaluation:
Medical history (with special stress on age of onset of diabetes mellitus (DM), condition of metabolic control and presence of associated systemic complication related to DM such as hypertension and renal impairment).
Ophthalmological examination included: best corrected visual acuity (BCVA) determined using Snellen charts in a standardized fashion ,best corrected visual acuity were transformed to logarithmic scale ( log MAR:logarithm of the minimum angle of result), pupillary reaction (direct and consensual), slit lamp examination (with special focus on: presence of any corneal opacities that may affect vision, presence of any lens opacities, intraocular pressure (IOP)(it was measured by slit lamp mounted Goldmann's applanation tonometry), fundus biomicroscopy ( it was done after maximum pupillary dilation by tropicamide 1% and phenylepherine 2.5% using both slit lamp biomicroscopy with non-contact (+90D) Volk lens and Goldman contact lens in order to detect diffuse macular oedema, to evaluate vitreo-retinal interface relationship, to check any pre-retinal membranes and previous macular laser treatment), fundus photography, fundus fluorescein angiography to confirm macular leakage, optical coherence tomography (OCT) to confirm macular thickening, assess vitreoretinal relationship and demonstrate cystoid spaces and multifocal electro-retinagram MF-ERG to assess macular function.
MFERG:
All ERG data were recorded using (Roland Consult, Brandenburg, Germany). Stimulation and recording of MF-ERG responses were performed using the ISCEV guidelines. [6] The stimulus, consisting of (61) hexagons covering a visual field of 30o was presented at a frame rate of 75Hz on a monitor 30cm from the patient’s eye. The luminance (97%) of each hexagon independently alternated between black and white. The amplifier gain was set at 100,000, the lower cutoff frequency
were 5 Hz and the upper frequency being 100 Hz. After maximum dilation of the pupil, Dawson Trick litskow (DTL) electrode were applied to topically anaesthetized cornea with one ground electrode in the forehead and two temporal reference electrodes and the opposite eye occluded. The
Eyes were optically corrected for near vision in order to see clearly the small fixation spot in the center of the stimulus matrix. and the patients were instructed to fixate at the intersection of the spokes. The recording period was comprised of eight segments of 30 second, providing a total recording time of 4minute. The quality of the recording was controlled by real-time display and contaminated segments were discarded & repeated
The MF-ERG stimulus location and anatomical areas corresponded roughly to the following: ring 1 to fovea, ring 2 to the parafovea, ring 3 to perifovea, ring 4 to the near periphery and ring 5 to central part of the middle periphery.[11]
The response density (amplitude per unit of retinal area (nv/deg2) of each local response and latency were estimated over central ring and four quadrants.
OCT:
OCT was performed on every patient using (Topcon, three dimensional (3D) OCT, -1000, -USA). After dilation of the pupil. Central retinal characteristics were analyzed by optical coherence tomography utilizing 6 radial line scans (6mm) directed on the fovea as determined by simultaneous evaluation of the red-free image on the computer monitor of the OCT scanner. The retinal thickness of the 1mm central retina was obtained using the macular thickness map for calculation
Triamcinolone Acetonide Injection:
For IVTA injection, topical 1
The study included one hundred and twenty eyes of eighty patients, forty patients were bilaterally studied (50%) and forty patients were unilaterally studied (50 %). Forty five (45) patients were female (56%) and thirty five (35) patients were male (44%). All procedures were carried out in accordance with the tenets of the Declaration of Helsinki (1989) of the world medical association. The study was approved by Mansoura University Hospital Trust Ethics Committee.
The patients aged from forty (40) years up to sixty – five (65) years with a mean age fifty (50) years. Most of them suffered from type II diabetes (46 patients (57.5%) with mean duration of the disease 10 years (SD±3) (table 1)
Fifty eyes suffered from diffuse maculopathy, fifty eyes suffered from cystoid maculopathy and twenty eyes suffered from mixed maculopathy. Macular edema has been present for 6 month(8±2months) All patients were treated with intra-vitreal injection of 4 mg. triamcinolone acetonide using the same technique. Among (120) eyes: sixteen eyes (13.3%) had marked improvement in visual acuity (3 lines in landolt chart ), 32 eyes (26.6 %) had moderate improvement (2 lines), 60 eyes (50 %) had mild improvement in visual acuity (one line in londolt chart ) and 12 eyes (10 %) had no improvement in visual acuity after one week. The improvement noticed in the first six months is included in table 2.
By OCT studying (table 3,fig 4) ,the study revealed marked improvement ( more than 120 μm ) in 20 eyes (16.6 % )with macular edema depending on the retinal thickness measured from the retinal surface to the retinal pigment epithelium before and after treatment as central retnial thickness ( before treatment ) ranged from 550 micron (μm) to 700 μm with mean thickness 570 μm ±SD 90 μm reduced into mean thickness 400 μm ±SD 50 μm after treatment with mean reduction ( 170 μm ), 36 eyes ( 30 % ) with moderate reduction as central thickness ranged from 450 μm to 350 μm before treatment with mean thickness was 400 μm reduced into mean thickness was 300 μm with mean reduction was 100 μm after treatment , 48 eyes ( 46.6 %) with mild reduction as retinal thickness ranged from 350 to 305 μm with mean thickness was 300 μm reduced into mean thickness 255 μm with mean reduction 45 μm and eight eyes had no improvement after treatment .Although macular thickness was significantly reduced ,values were higher than normal (<200>
There was good correlation between retinal thickness and visual acuity (R=-5.00, P=0.01). The reduction in retinal thickness was associated with improvement of visual acuity
Flourescein Angiography showed leakage from macular area in all cases before IVTA. After IVIA, there was reduction of the macular leakage in most of the cases (116 eyes) (96.6 %)
The retinal response density of MF-ERG in affected eyes before treatment ranged from 15 nv/deg2 to 2 nv/deg2 (mean value ± SD 7.4 ±5.5 nv/deg). After treatment, the response density ranged from 22 to 17 (mean value ±SD 15.3 ± 6.4). Table 4 (Fig.1-3)
The latency of MF-ERG in eyes before treatment ranged from 70 millisecond (ms ) to 59 ms ( mean value ±SD 65 ±2 ms)
After treatment the latency ranged from 54 to 58 ms (mean ± SD 55± 3.1 ms )
There was good correlation between increased amplitude of MF-ERG and decreased macular thickness by OCT ( R=0.54 , P=0.008 )
The IVTA effect (OCT improvement, MFERG changes and visual acuity improvement) regressed 2 months after injection in group 1 while in group 2, there were more stabilization of improvement.
Post-Treatment Complication:
Intra-ocular pressure: The mean pre-injection IOP was 15 ± 2.2.
The mean post injection IOP was 17 ±3.5 . There was only four cases (3.3%) develop mild increase in IOP (It was 26 mm Hg) and was controlled with B-blocker
Minor local adverse events related to the treatment procedure (conjunctiva hyperemia and subconjuctival haemorrhage) were presented in 6 cases only (5% ) during the first week
Lens status: The lens was clear in all patient before treatment. At the end of follow up, none of the eyes displayed any cataract.
There were no cases of endophthalmitis, clinically evident inflammation, retinal tear, retinal detachment or thrombi embolic.
Diabetic macular edema is a major complication of diabetic retinopathy that faces a challenge in its management . Although several treatment modalities have been tried for the management of diabetic macular edema, these modalities have many limitations. Focal and grid laser photocoagulation have remained the primary treatment option for diabetic macular edema for several years. However most eyes treated with laser photocoagulation do not have an improvement in visual acuity. Although ETDRs,[2] demonstrated that immediate focal photocoagulation reduced moderate visual loss by 50%, 12% of treated eyes still lost vision at the 3-year follow up interval and 24%of immediately treated eyes had thickening involving the center of the macula at 36 months .In addition , laser treatment of eyes with diffuse macular edema has been disappointing .[15,16]
In the past years, attempts to understand the pathogenesis of diabetic retinopathy had led to other strategies in the management of diabetic macular edema . The development of diabetic retinopathy is a multifactorial process. Much of retinal damage that characterizes the disease is now understood to result from retinal vascular leakage and non perfusion mediated by numerous growth factors.[17,18] The up regulation of growth factors is associated with breakdown of the blood – retinal barrier with increased vascular permeability resulting in retinal oedema, stimulation of endothelial cell growth and neovasculization.[19]
For years, corticosteroids have been used in ophthalmology to suppress intraocular inflammation and reduce leakage from retinal blood vessels . Local application of cortisone was used to decrease the adverse side effects of systemic cortisone and at the same time achieve a higher concentration at the site of action . The use of intraocular corticosteroids for diabetic macular oedema started after the significant observations of McCuen et al , [20] and Young et al, [21] on the lack of toxicity of intra-vitreal triamcinolaone (9-fluoro – 16 – hydroxyl prednisolone ) . Subsequently , there have been several studies documenting the antiangiogenic , anti proliferative and antiedematous effects of IVTA. The landmark study by Martidis et al [22] involved sixteen eyes with clinically significant macular oedema that failed to respond to at least two previous sessions of laser photocoagulation at least 6 months after laser therapy, the response was measured by clinical examination and OCT. Eyes with residual central macular thickness more than 300 µm. were administered an intravitreal injection of 4mg in 0.1 ml of trimacinolone acetonide. The central macular thickness deceased after injection by 55%, 57
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