Subthreshold micropulse diode laser treatment in diabetic macular oedema

BACKGROUND/AIM: Enlargement of laser scars after retinal argon laser photocoagulation can give rise to deterioration in visual acuity. Subthreshold micropulse diode laser may decrease this risk. The aim of this study was to compare the effectiveness of subthreshold micropulse diode laser (810 nm) and conventional argon laser (514 nm) photocoagulation for the treatment of clinically significant macular oedema in diabetic patients. METHODS: 23 eyes of 16 patients were randomised to either treatment. Follow up was conducted for a minimum of 5 months. Changes in visual acuity and macular oedema measured by optical coherence tomography were examined. RESULTS: Visual acuity remained stable in all treatment groups throughout the observation period. Changes in retinal thickness were small both foveally and perifoveally. In patients with focal macular oedema a significant reduction in retinal thickness (9% approximately -26 microm, p = 0.02) was seen foveally 3 months after diode laser photocoagulation. CONCLUSION: Subthreshold micropulse diode laser and conventional argon laser treatment showed an equally good effect on visual acuity. Subthreshold micropulse diode laser showed a stabilising or even improving effect on macular oedema. The combination of primary diode laser and supplementary argon laser might be particularly favourable in reducing diabetic macular oedema.     

Subthreshold diode micropulse photocoagulation for the treatment of clinically significant diabetic macular oedema

AIM: To report the visual and clinical outcomes of a pilot study of subthreshold diode micropulse (SDM) laser photocoagulation for clinically significant diabetic macular oedema (CSMO). METHODS: The results of infrared (810 nm) SDM laser photocoagulation for CSMO were retrospectively reviewed in 95 eyes of 69 consecutive patients with mild to moderate non-proliferative diabetic retinopathy. The same laser parameters were used for each patient. Only the number of laser applications varied between patients, depending on their macular findings. Primary outcome measures were Snellen visual acuity, fluorescein angiographic leakage, and CSMO status. RESULTS: Visual acuity was stable or improved in 85% of treated eyes, with a mean follow up of 12.2 months (range 3-29 months). CSMO decreased in 96% and resolved in 79% of treated eyes. No adverse laser events occurred. No laser lesions were detectable ophthalmoscopically or angiographically after treatment, consistent with calculations based on ANSI Z136.1 laser safety standards suggestive of only histologically detectable tissue effects at the laser exposure levels. No laser scarring was observed during the follow up period. CONCLUSION: Subthreshold diode micropulse laser photocoagulation minimises chorioretinal damage in the management of CSMO and demonstrates a beneficial effect on visual acuity and CSMO resolution. Prospective studies are needed to fully evaluate this technique.     

Retinal thickness variation in the diabetic patient measured by the retinal thickness analyser

AIM—To evaluate the potential of the retinal thickness analyser (RTA) as an objective tool for assessment and follow up of diabetic macular oedema.
METHODS—A prototype of the RTA that operates on the principle of laser slit biomicroscopy was used. Retinal thickness was obtained in 41 eyes of 41 diabetic patients. The clinical diagnosis was cystoid macular oedema (CMO) in 10 eyes, clinically significant macular oedema (CSMO) without retinal cysts in 21 eyes, and "dry" macula following grid pattern laser treatment in 10 eyes. The control group consisted of 46 eyes of age matched healthy volunteers.
RESULTS—In normal eyes (46 eyes), the foveal thickness measured was 178 (SD 44) µm and the macular thickness around the fovea was 311 (51) µm. The eyes with CMO displayed the largest foveal thickening, 875 (287) µm (390% increase compared with normal values). The average thickness of the fovea in the non-cystoid CSMO group was 427 (175) µm (144% increase compared with normal fovea). The average thickness of the foveal centre in eyes judged as having "dry" macula after laser treatment was 315 (71) µm (77% increase compared with normal value and a 26% decrease in thickness compared with the CSMO eyes). Statistically significant differences were found in central thickness between these four groups (p = 0.0001). The average thickness at 500 µm surrounding the fovea was 566 (202) µm in the CSMO eyes compared with 311 (51) µm in normal eyes (80% increase). The "dry" macula group (after undergoing laser treatments) had an average thickness of 414 (94) µm (27% decrease compared with CSMO eyes and a 33% increase compared with eyes of healthy controls).
CONCLUSIONS—RTA is a system for quantifying macular thickness and imaging of macular pathology. The system can be a useful tool for diagnosis of macular diseases and for evaluation of the effect of treatment modalities.

Keywords: diabetic retinopathy; retinal thickness; macular oedema; retinal imaging     

Contrast sensitivity following focal laser photocoagulation in clinically significant macular oedema due to diabetic retinopathy

Purpose : To evaluate the influence of focal laser photocoagulation on contrast sensitivity in diabetic patients with clinically significant macular oedema (CSMO). Methods : A prospective non‐comparative interventional study was performed on a group of patients with CSMO at Dr Rajendra Prasad Centre for Ophthalmic Sciences, New Delhi, a tertiary eye care centre. Thirteen diabetic patients (14 eyes) with CSMO and no history of prior photocoagulation were recruited for this study. Direct focal photocoagulation of all leaking microaneurysms was performed using an argon green laser (514 nm). A contact lens was used as a slit lamp delivery system. Evaluation of the best corrected Snellen visual acuity, contrast sensitivity, slit lamp biomicroscopy, macular status on direct ophthalmoscopy and fluorescein angiography was carried out 1 month and 3 months after laser photocoagulation. Results : Following direct focal laser photocoagulation, focal CSMO resolved completely in all but one eye, 4–8 weeks later, as seen on slit lamp biomicroscopy and/or fluorescein angiography. Post‐treatment, visual acuity remained stationary in eight eyes, improved by one line in three eyes, by two lines in two eyes and by three lines in one eye. The mean ± SD pretreatment and post‐treatment decimal visual acuities were 0.49 ± 0.30 and 0.59 ± 0.28, respectively. The mean ± SD pre‐laser contrast sensitivity score was 121.3 ± 83.6, which increased significantly to a mean ± SD of 151.6 ± 80.5 following direct focal photocoagulation. Conclusion : Focal argon laser photocoagulation in CSMO in diabetics helps in improving the contrast sensitivity and stabilizes the visual acuity. The changes in contrast sensitivity and visual acuity are independent of each other.     

Effect of grid laser photocoagulation in diffuse diabetic macular edema in correlation to glycosylated haemoglobin (HbA1c)

Background Glycosylated haemoglobin (HbA1c) correlates with the amount of hyperglycemia in diabetic patients. High HbA1c levels often predict clinically significant macular edema (CSME), which then needs to be treated with grid laser photocoagulation. The question asked in this study was whether there is a correlation between the effect grid laser photocoagulation in diffuse diabetic macular edema and HbA1c, using an optical coherence tomography (OCT) for the evaluation of the retinal thickness. Methods A prospective, non-comparative case series was performed to find a correlation between the effect of grid laser photocoagulation in diffuse diabetic macular edema and HbA1c. Thirty eyes with CSME of diabetic patients were included in the study. Complete ophthalmic examinations and OCT were performed at baseline, 1 month, 3, and 6 months after grid laser photocoagulation therapy. HbA1c was measured at the end of study. Results Significance level was set at P<0.05. A significant difference in the foveal (P=0.02) and superior (P=0.021) retinal thickness 6 months after laser therapy, no correlation between HbA1c and retinal thickness after photocoagulation, and an insignificant decrease in visual acuity (P=0.9) were found. The correlation between foveal retinal thickness and visual acuity was P=0.24 6 months after treatment. Conclusion There was no significant correlation between HbA1c and the effect of grid laser photocoagulation therapy in diffuse diabetic macular edema. The retinal thickness decreased significantly in the foveal and superior area 6 months after therapy. No correlation between the foveal retinal thickness and the visual acuity was found. The visual acuity did not increase after treatment. There are many factors influencing the retinal thickness, such as the blood pressure and the attached posterior hyaloid.     

Diabetic macular oedema: the effect of photocoagulation on fluorescein transport across the blood-retinal barrier

BACKGROUND/AIM: The visual loss secondary to diabetic macular oedema can be controlled to some extent by photocoagulation, though the mechanism of action is largely unknown. The purpose of the present study was to quantitate the effect of photocoagulation on the blood-retinal barrier using fluorescein as a tracer of passive and active transport. METHODS: A prospective study of 46 eyes in 34 patients with clinically significant macular oedema (CSMO) examined by vitreous fluorometry before and 6 months after macular photocoagulation treatment. RESULTS: In 23 eyes CSMO was not present at follow up (responding eyes), in another 23 other eyes CSMO was still present (non-responding eyes). With reference to the presence or absence of CSMO at follow up, the passive transport (permeability) for responding eyes decreased after photocoagulation in contrast with an increase in non-responding eyes; the difference between the groups at follow up was significant (p=0.03). The active transport for responding eyes decreased slightly at follow up, while it increased for non-responding eyes; the difference between the groups at follow up was not significant (p=0.09). CONCLUSION: Following photocoagulation a reduction of diabetic macular oedema, defined as disappearance of CSMO, is paralleled by a decrease of the passive permeability while the hypothesis of an increase in the active transport from the retina to the blood could not be supported by this study.     

Effective treatment of diffuse diabetic macular edema by temporal grid pattern photocoagulation.

BACKGROUND AND OBJECTIVE: To determine the effectiveness of laser grid pattern photocoagulation to the macula but not the papillomacular bundle for the treatment of diffuse diabetic macular edema. PATIENTS AND METHODS: Thirty-five eyes of 23 patients with diffuse diabetic macular edema underwent laser grid photocoagulation excluding the papillomacular bundle area. Best-corrected visual acuity by Snellen chart, foveal thickness using a retinal mapping program by optical coherence tomography (OCT), and mean deviation sensitivity by Humphrey automated central perimetry were investigated before and 1, 3, and 6 months after the treatment. RESULTS: Six months after treatment, the visual acuity was improved by 2 or more lines in 16 eyes (43%) and the foveal thickness decreased in 32 eyes (91%). The mean deviation worsened in 34 eyes (97%). There was a significant correlation between the improvement of visual acuity and the initial mean deviation, suggesting that a better visual acuity would be expected with a preoperative mean deviation of approximately -20 dB. CONCLUSION: Grid pattern photocoagulation without treatment to the papillomacular bundle area was effective in treating diffuse diabetic macular edema, especially in eyes with an initial mean deviation showing moderate dysfunction.     

Role of OCT in the diagnosis and follow up of diabetic macular edema

The aim is to present, along with a brief literature review, the results of OCT scan in eyes with diabetic macular edema (DME), as well as examples of the utility of OCT for different therapeutic approaches. One-hundred and thirty-six eyes with diabetic retinopathy were analyzed with OCT to explore the different patterns of DME. Some eyes with DME were studied with OCT pre and postoperatively to determine the efficacy of photocoagulation and vitrectomy to restore a normal macular profile. Sixty-eight eyes with a central foveal thickness of 200 mu or more were considered "edematous". Three different patterns of DME were recognized and analyzed: macular thickening, cystoid macular edema and shallow retinal detachment. The change in macular profile and internal retinal structure after laser or surgical treatment are well visible with OCT. OCT contributes in understanding the anatomy of DME and the intraretinal damage and seems to be the technique of choice for the follow-up of macular edema. We think that this tool should always be used in monitoring the effect of therapies in future studies.     

Serial optical coherence tomography of subthreshold diode laser micropulse photocoagulation for diabetic macular edema.

BACKGROUND AND OBJECTIVE: To use serial optical coherence tomography (OCT) to evaluate low-intensity, high-density subthreshold diode laser micropulse photocoagulation treatment of clinically significant diabetic macular edema. PATIENTS AND METHODS: Eighteen consecutive eyes of 14 patients with clinically significant diabetic macular edema and a minimum foveal thickness of 223 microm or greater were prospectively evaluated by OCT preoperatively and 1, 4, and 12 weeks following treatment. RESULTS: Overall, estimated macular edema 3 months postoperatively (minimum foveal thickness--223 microm) was reduced a mean of 24% (P = .02). Eleven eyes treated for recurrent or persistent clinically significant diabetic macular edema following prior treatment more than 3 months before study entry were most improved, with a mean reduction in estimated macular edema 3 months postoperatively of 59%. No treatment complications were observed. No patient demonstrated laser lesions following treatment. CONCLUSIONS: Low-intensity, high-density subthreshold diode laser micropulse photocoagulation can reduce or eliminate clinically significant diabetic macular edema measured by OCT. Further study is warranted.     

早期和晚期激光治疗视网膜分支静脉阻塞的疗效比较

目的:比较早期行氪激光视网膜光凝治疗视网膜分支静脉阻塞和晚期激光治疗的疗效.方法:视网膜分支静脉阻塞患者125例125眼分为早期治疗组68例68眼和晚期治疗组57例57眼,初诊时行视力、眼压、眼底、FFA和OCT检查.早期组在初诊时行氪激光光凝治疗:除出血区行氪红激光和波及黄斑区行氪黄激光,其余行氪绿激光,激光术后给予球后注射曲安奈德40mg.晚期组在初诊时口服沃丽汀、维生素C和安多明等药物,若病变波及黄斑区引起黄斑水肿者行球后注射曲安奈德40mg.1,3,6,12mo行复诊,复诊时行视力、眼压、眼底、FFA和OCT检查.若FFA检查发现晚期组视网膜出现毛细血管无灌注区行氪激光光凝治疗.随访时间为1a.结果:早期组68眼中视力提高49眼(72.1%),视力稳定16眼(23.5%),视力下降3眼(4.4%);晚期组57眼中视力提高35眼(61.4%),视力稳定8眼(14.0%),视力下降14眼(24.6%).FFA和OCT检查发现早期组黄斑水肿消失或减轻的时间比晚期组明显缩短,视网膜出血吸收的时间也比晚期组缩短.早期组中没有1眼发生黄斑囊样变性、黄斑裂孔和玻璃体出血,晚期组中有14眼发生黄斑囊样变性或黄斑裂孔,有9眼发生玻璃体出血导致视力显著下降.结论:早期行氪激光视网膜光凝治疗视网膜分支静脉阻塞的疗效明显优于晚期激光治疗,早期治疗能最大限度保存和提高患者的视力.早期行激光治疗未发现明显的不良反应,是安全有效的方法.     

Intravitreal triamcinolone as an adjunct in the treatment of concomitant proliferative diabetic retinopathy and diffuse diabetic macular oedema

PURPOSE: To investigate if triamcinolone acetonide (TA) can be an adjunct to laser treatment in patients with concomitant non-high-risk proliferative diabetic retinopathy (PDR) and diffuse clinically significant diabetic macular oedema (CSMO). METHODS: This prospective, interventional and comparative clinical study included 32 eyes of 16 patients with bilateral concomitant non-high-risk PDR and diffuse CSMO. Each patient received 4 mg intravitreal TA for the eye with worse visual acuity (study group) and macular focal and grid laser photocoagulation (MP) for the other eye (control group). One month later, each patient received four sessions of panretinal photocoagulation for both eyes plus MP for the eyes in the study group. The visual and angiographic results of both groups were compared. RESULTS: In the study group, the mean visual acuity (VA) improved from 0.12 +/- 2.3 lines at the baseline to 0.19 +/- 3.1 (P = 0.004), 0.20 +/- 3.2 (P = 0.004), 0.19 +/- 3.6 (P = 0.009) and 0.19 +/- 3.3 lines (P = 0.091) at the 1-, 3-, 6- and 9-month follow-up intervals, respectively. The macular oedema was found to be resolved in 11 eyes (69%) and decreased in five eyes (31%). In the control group, the mean VA deteriorated progressively from 0.41 +/- 3.1 lines at the baseline to 0.20 +/- 3.1 lines (P = 0.026) at the end of the study and the macular oedema decreased only in three eyes (19%) at the sixth follow-up month. CONCLUSIONS: During the follow-up period of the study, intravitreal TA as an adjunct in the treatment of concomitant non-high-risk PDR and diffuse CSMO led to a more-favourable clinical outcome than conventional laser treatment.     

Qualitative and quantitative OCT response of diffuse diabetic macular oedema to macular laser photocoagulation

Purpose

To assess the quantitative and morphological changes of the macula in response to macular grid laser for diabetic macular oedema (DMO) using optical coherence tomography (OCT).

Patients and Methods

Cirrus OCT macular cube scans of 30 eyes of 25 patients were retrospectively analysed before and 4 months after macular grid laser for diffuse DMO. The oedema was quantified and response evaluated in the nine early-treatment diabetic retinopathy study (ETDRS) zones of the macula. Post-laser OCT changes were compared with the baseline features, including morphology patterns, changes in both logarithmic transformed (logOCT) and standardised average macular thickness (AMT), total macular volume, number of parafoveal quadrants involved, and the presence of intact 3rd hyper-reflective band (HRB).

Results

The rate of change of retinal thickness in response to laser was maximum in the central (8.17%) and perifoveal inferior quadrants (0.04%). Diffuse retinal thickening on OCT responded best to treatment. The AMT of 300–350 μm had the worst response (+0.94%). Eyes with less than four quadrants of oedema showed good response. Disrupted HRB was associated with poor visual gain (−0.33 ETDRS letters).

Conclusion

The topographic location of oedema on the retinal map and the morphological patterns of the oedema on OCT are useful predictors of treatment response in diffuse DMO.     

Intravitreal triamcinolone as adjunctive treatment to laser panretinal photocoagulation for concomitant proliferative diabetic retinopathy and clinically significant macular oedema

Purpose: To evaluate the effect of intravitreal injections of triamcinolone acetonide (IVTA) combined with panretinal photocoagulation (PRP) on visual acuity (VA) and foveal thickness in patients with concomitant high‐risk proliferative diabetic retinopathy (PDR) and clinically significant macular oedema (CSMO). Methods: This retrospective interventional case series included seven eyes diagnosed with both high‐risk PDR and CSMO that underwent PRP and a single injection of 4 mg of IVTA. The main outcome measures were VA and foveal thickness, measured by optical coherence tomography (OCT) before treatment and throughout the follow‐up period. Results: Median follow‐up was 301 days (range 180–715 days). Foveal thickness data were available for four of seven eyes. Before the combined treatment, median LogMAR (logarithm of the minimum angle of resolution) VA and median foveal thickness were 1 (Snellen 20/200, range 20/40–20/800) and 559 µm (range 333–689 µm), respectively. After treatment, median vision improved to LogMAR 0.544 (Snellen 20/70, range 20/40–20/1000) (P = 0.13). Vision improved or remained stable in six of seven eyes. Median foveal thickness at final follow‐up was 436 µm (range 259–623 µm) (P = 0.15). Foveal thickness decreased or remained stable in all eyes. Conclusion: The addition of IVTA to PRP in the treatment of eyes with high‐risk PDR and CSMO may prevent PRP‐induced foveal thickening and loss of vision.     

Can optical coherence tomography predict the outcome of laser photocoagulation for diabetic macular edema?

BACKGROUND AND OBJECTIVE: To assess the outcome of laser photocoagulation in patients with diabetic macular edema. PATIENTS AND METHODS: Forty-seven patients (51 eyes) with clinically significant macular edema (CSME) undergoing grid laser photocoagulation were included. Clinical examination and optical coherence tomography (OCT) were performed at baseline and 3 to 4 months after treatment. The central foveal thickness, mean inner macular thickness (average retinal thickness in fovea and inner macular circle), and mean macular thickness were calculated. Based on the greatest OCT thickness at baseline, patients were grouped according to mild (< 300 microm; Group 1), moderate (300 to 399 microm; Group 2), and severe (> or = 400 microm; Group 3) macular edema. RESULTS: Group 2 showed significant reductions in central foveal thickness (23 microm, P = .02), mean inner macular thickness (18 microm, P = .02), and mean macular thickness (9 microm, P = .04) with slight improvement in visual acuity. Groups 1 and 3 did not show any significant change in macular thickness values and there was a statistically insignificant worsening of visual acuity in these groups. CONCLUSIONS: Patients with moderate macular thickening of 300 to 400 microm benefit most from laser treatment. OCT may help in choosing the appropriate treatment for CSME based on the degree of macular thickening. Long-term studies are warranted to confirm these findings.     

Role of OCT in the diagnosis and follow up of diabetic macular edema

The aim is to present, along with a brief literature review, the results of OCT scan in eyes with diabetic macular edema (DME), as well as examples of the utility of OCT for different therapeutic approaches. One-hundred and thirty-six eyes with diabetic retinopathy were analyzed with OCT to explore the different patterns of DME. Some eyes with DME were studied with OCT pre and postoperatively to determine the efficacy of photocoagulation and vitrectomy to restore a normal macular profile. Sixty-eight eyes with a central foveal thickness of 200µ or more were considered “edematous”. Three different patterns of DME were recognized and analyzed: macular thickening, cystoid macular edema and shallow retinal detachment. The change in macular profile and internal retinal structure after laser or surgical treatment are well visible with OCT. OCT contributes in understanding the anatomy of DME and the intraretinal damage and seems to be the technique of choice for the follow-up of macular edema. We think that this tool should always be used in monitoring the effect of therapies in future studies.     

The predictive value of optical coherence tomography after grid laser photocoagulation for diffuse diabetic macular oedema

Purpose: To assess the predictive value of optical coherence tomography (OCT) mapping of retinal thickness and intraretinal morphological changes after macular grid for diffuse diabetic macular oedema (DMO). Methods: We carried out a prospective, non‐controlled, case series study, in which 28 consecutive eyes with previously untreated diffuse DMO underwent fundus photography and OCT at baseline and at 1, 3 and 6 months after treatment. Results: Macular photocoagulation was followed by a significant reduction in retinal thickness in the foveal centre (? 80 μm) and in the foveal subfield (? 65 μm) from baseline to 6 months (p < 0.01). The bulk of the reduction in retinal thickness and macular volume was manifest after 1 month. No significant change in retinal thickness occurred from 1 to 3 months or from 1 to 6 months in any macular subfield (p > 0.05). The relative decrease in retinal thickness at 6 months was highest in the foveal centre (? 22%), followed by the foveal region (? 18%), the inner parafoveal region (? 8%), and the outer parafoveal region (? 2%). Thus, the effect of photocoagulation on retinal thickness decreased with increasing eccentricity (p < 0.025). Overall, there was no statistically significant change in best corrected visual acuity (BCVA) between baseline and follow‐up (p < 0.05), but changes in foveal subfield thickness and changes in VA were highly correlated (r = 0.66, p < 0.0001). Visual outcome (final BCVA) and final foveal subfield thickness at 6 months were correlated with the pattern of intraretinal morphological changes at baseline (Spearman’s correlation coefficient r = ? 0.41, p = 0.03 and r = 0.45, p = 0.02, respectively). In addition, visual outcome (final BCVA) and final foveal subfield thickness at 6 months were correlated with baseline foveal thickness (Spearman’s correlation coefficient (r = ? 0.37, p = 0.05 and r = 0.5, p = 0.01, respectively). Conclusions: It seems that the 1‐month time‐point after macular laser treatment is a critical point for establishing the outcome of this modality of management of DMO. Baseline OCT mapping of intraretinal fluid accumulation patterns and foveal thickness can help to predict the final visual outcome and final foveal thickness, but not the absolute change in either of these parameters after macular laser therapy.     

Vitrectomy results in diabetic macular oedema without evident vitreomacular traction

PURPOSE: To determine the effectiveness of vitrectomy in eyes with diabetic macular oedema without evident traction from a thickened vitreous membrane. METHODS: Twenty-one consecutive eyes from 19 patients with diabetic macular oedema that had undergone vitrectomy were analysed retrospectively. All eyes had an attached posterior hyaloid membrane in the macular region, but without thickening and without evident traction on the macula. A standard pars plana vitrectomy with the creation of a posterior vitreous detachment was performed. RESULTS: Median duration of macular oedema at the time of vitrectomy was approximately 11.0 months (range 2-36 months). The median preoperative best-corrected visual acuity of 0.08 (range hand motions/0.003 to 0.4), improved by 5 lines to a median final postoperative best-corrected visual acuity of 0.25 (range 0.025-0.5) (P = 0.001). Seven eyes without preoperative macular photocoagulation had a median visual acuity improvement of 77%, range 32-400%, while 12 eyes with preoperative macular laser treatment had a median visual acuity improvement of 14.8%, range 0-66.1% (P = 0.02, CI 95%, after multivariate regression analysis). In all 21 eyes, macular oedema was no longer visible on microscopic examination after a median period of 3.0 months (range 1-9 months) after vitrectomy. CONCLUSIONS: In eyes with diabetic macular oedema without evident macular traction from a thickened vitreous membrane, vitrectomy resulted in the resolution of macular oedema, with an improvement in visual acuity in the majority of cases. Eyes without preoperative macular photocoagulation had a significantly higher percentage visual improvement than eyes without preoperative macular laser treatment. A randomised controlled prospective trial of primary vitrectomy versus macular photocoagulation is needed to determine the role of vitrectomy as treatment modality for diabetic macular oedema.     

Visual outcome after phacoemulsification and IOL implantation in diabetic patients

AIMS: To follow visual acuity (VA) and progression of diabetic retinopathy (DR) after phacoemulsification in diabetic patients with different stages of DR and controls. METHODS: This prospective study included 27 diabetic patients with no or mild to moderate non-proliferative DR; 25 patients with moderate to severe non-proliferative, or proliferative DR; and 22 non-diabetic controls. All patients underwent uncomplicated, phacoemulsification surgery, with implantation of a heparin-surface modified (HSM) poly(methylmethacrylate) (PMMA) intraocular lens (IOL) into the capsular bag. Colour fundus photographs and fluorescein angiograms (FA) were taken at 1 week (baseline), 3 months, and 1 year postoperatively to determine stability or progression of DR. RESULTS: The VA of 46 diabetic eyes (88%), was improved 1 year after surgery and only six eyes (12%) were unchanged or worse. 41 diabetic eyes (79%) achieved a VA of 0.5 or better and 11 eyes (21%) had a final VA lower than 0.5. Significantly lower final corrected VA was found 1 year after surgery in eyes with advanced DR (median 0.5; range 0.1-1.0) compared with controls (1.0; 0.1-1.0) and eyes with no or mild to moderate DR (1.0; 0.1-1.0). Eyes with mild to moderate DR and clinically significant macular oedema (CSMO) 1 week postoperatively had a lower final VA than those without CSMO. Angiographic cystoid macular oedema (CMO) was detected with FA in 15% of all diabetic eyes 1 week postoperatively. 41 eyes (79%) showed no change or improvement of the retinal status 1 year after cataract surgery. Progression was found in 11 eyes (21%), mainly in eyes with mild to moderate DR and moderate to severe DR. Eyes with an indication for laser photocoagulation at baseline showed a significantly higher rate of progression of DR after surgery than those without indication for laser treatment. CONCLUSION: The final visual outcome was improved in the majority of diabetic eyes. Eyes with CSMO at the time of surgery had the worst prognosis regarding postoperative VA.     

Retinal thickness change after focal laser treatment of diabetic macular oedema.

Laser photocoagulation has been used successfully for the treatment of clinically significant macular oedema to reduce the risk of loss of vision in diabetic patients. A quantitative method for measuring retinal thickness was applied to 20 patients with diabetic macular oedema before and 4 months after focal laser treatment to assess the reduction in retinal thickening and its relation to visual acuity. The degree of thickening at each location, defined by thickness index, was determined relative to the corresponding average value in normal subjects. Comparison of quantitative retinal thickness measurements before and after treatment demonstrated that treatment at thickness indices of approximately 1.6 (60% thickening) has nearly 50% probability for reversal of thickening to within the normal range (< or = 1.3), whereas at thickness indices greater than 2.8 (180% thickening) there is less than 2.5% probability that reversal will occur. The level of foveal thickening before treatment strongly correlated with the degree of thickening after treatment. Most of the eyes with an improvement in visual acuity had a foveal thickness within the normal range at 4 months' follow up. These findings suggest that quantitative retinal thickness measurement provides an objective assessment of the degree of macular oedema and can be useful for monitoring the efficacy of focal laser treatment in reducing the thickening and relating the latter to visual outcome.     

Quantitative analysis of diabetic macular edema after scatter laser photocoagulation with the scanning retinal thickness analyzer

PURPOSE: To define the effect of scatter laser photocoagulation on foveal retinal thickness. METHODS: A commercial scanning retinal thickness analyzer was used to measure retinal thickness. The foveal retinal thickness was measured at the central area of the fundus (0.4 x 0.4 mm). The method was applied to 20 consecutive patients (mean age, 52.4 +/-16.9 years) with diabetic retinopathy. Measurements were performed before and 6 weeks after scatter photocoagulation. Patients were examined by fluorescein angiography and slit-lamp biomicroscopy to detect macular edema. RESULTS: Mean foveal thickness before scatter photocoagulation was 187+/-45 microm, increasing to 221+/-46 microm after the treatment (P = 0.0001). The foveal thickness increased in 12 eyes (60%). Laser treatment increased macular permeability in two eyes (10%). Biomicroscopic examination revealed central macular thickening in one eye (5%). Visual acuity was reduced in four eyes (20%). CONCLUSIONS: Our results suggest that subclinical macular edema occurs after scatter laser photocoagulation. The retinal thickness analyzer is a sensitive tool for early detection of macular edema after laser treatment, because increases in retinal thickness as small as 34 microm cannot be assessed by slit-lamp biomicroscopy.