Early vitrectomy for progressive diabetic proliferations covering the macula

Current treatment approaches in diabetic macular edema

PURPOSE

To review current treatment approaches in diabetic macular edema (DME).

METHODS

The underlying pathopathology, classifications and diagnostic examination techniques including fluorescein angiography, optical coherence tomography and stereoscopic biomicroscopy. Treatment modalities with focal or grid argon laser photocoagulation, pars plana vitrectomy with and without peeling of the inner limiting membrane (ILM), as well as intravitreal injections using triamcinolone acetonide or novel vascular endothelial growth factor (VEGF) inhibitors are described.

RESULTS

DME results from a series of biochemical and cellular changes, causing progressive leakage and exudation. Focal and grid photocoagulation remains the standard care for diabetic maculopathy. However, the availability of new agents raises the possibility of improvements if significant benefits can be validated in randomized clinical trials. Posterior vitreous attachments play a critical role through several mechanical or physiological mechanisms. Vitrectomy without ILM removal seems to be effective in reducing the retinal thickness and improving visual acuity.

CONCLUSION

A proper evaluation of the vitreous and retina is fundamental to select the most appropriate treatment approach in DME. While small microaneurysms with focal DME may be treated by conventional focal photocoagulation, diffuse DME which do not respond to grid photocoagulation may benefit from intravitreal injections using triamcinolone acetonide or novel VEGF inhibitors. Eyes with DME and additional vitreous traction may benefit from pars plana vitrectomy without ILM peeling. A combination of laser, pharmacological and surgical treatment modalities may be necessary to maintain central vision in eyes with DME.

Improvement of visual acuity in eyes with diabetic macular edema after treatment with pars plana vitrectomy

BACKGROUND

Diabetic macular edema (DME) is the leading cause of severe visual loss in patients with diabetic retinopathy. This is so despite the fact that argon laser photocoagulation of the macula (M-ALC) has been shown to be beneficial. Recently, it has been suggested that pars plana vitrectomy (PPV) can lead to the resolution of DME and stop the deterioration of central visual acuity.

PURPOSE

To explore the potential benefit of PPV for the treatment of DME.

PATIENTS AND METHODS

PPV was carried out in 30 eyes of 21 consecutive patients (median age 71 years, range 61-88 years) with type II diabetes mellitus suffering from DME. 23 eyes had non-proliferative diabetic retinopathy (NPDR) and 7 eyes had proliferative diabetic retinopathy (PDR) in addition to DME. Posterior vitreous detachment had to be carried out in all cases. If epiretinal membranes were present (23 eyes), they were removed. In 13 eyes (initially 11 eyes) the internal limiting membrane (ILM) was also removed. Prior to PPV 8 eyes had received M-ALC. Three eyes had M-ALC after PPV. One eye developed a retinal detachment 6 weeks after PPV and was excluded form the analysis. After an initial treatment failure two eyes underwent repeat PPV with peeling of the ILM. Both eyes of another patient had 2 repeat PPVs because of recurrent vitreous hemorrhage. Median follow-up was 16 months (range 1-62 months).

RESULTS

Following PPV the macula flattened or became attached in 20/27 (74%) eyes. 15/18 (83%) eyes showed reduction or disappearance of leakage during fluorescein-angiography. Central visual acuity increased by two to six lines in 15/27 (56%) for the whole group at 6 months after PPV. For the subgroup (18 eyes) for which the evolution of visual acuity prior to PPV could be documented mean and median visual acuity had decreased markedly from 0.26 +/- 0.19 resp. 0.2 (range 0.03-0.6) to 0.12 +/- 0.09 resp. 0.1 (range 0.02-0.4) during the 12 months preceding PPV and increased to 0.28 +/- 0.23 resp. 0.2 (range 0.03-0.8) during the 12 months following PPV.

CONCLUSION

PPV almost always results in a reduction and often complete disappearance of DME as evidenced by ophthalmoscopy and fluorescein-angiography. Most importantly, central visual acuity often increases, sometimes to a very large extent with dramatic improvement in quality of life of the patients.

Vitrectomy in the management of diabetic retinopathy

According to the Early Treatment Diabetic Retinopathy Study, at least 5% of eyes receiving optimal medical treatment will still have progressive retinopathy that requires laser treatment and pars plana vitrectomy. During the past decade, improvements in instrumentation and surgical techniques have allowed more difficult cases of diabetic retinopathy to be candidates for vitrectomy. However, although the thresholds for performing surgery within established indicated situations have been lowered, only a few additional indications have been established. Although vitrectomy improves the prognosis for a favorable visual outcome, preventive measures, such as improved control of glucose levels and timely application of panretinal photocoagulation, produce better results. The authors review the indications, techniques, and results of vitrectomy in the management of diabetic retinopathy.

Vitrectomy in diabetic patients with a blind fellow eye

Results of pars plana vitrectomy for complications of proliferative diabetic retinopathy were analysed in 32 consecutive patients with a blind fellow eye due to diabetic eye disease. The mean follow-up period was 22.3 months. Only 16% of all eyes examined had received full scatter photocoagulation prior to referral for vitrectomy. Out of 9 eyes with vitreous haemorrhage, 8 improved to a visual acuity of > or = 0.2 postoperatively. Amid 23 eyes which were vitrectomized for advanced traction retinal detachment, only 4 eyes improved to a postoperative visual acuity of > or = 0.02. In this group 12 eyes deteriorated after vitrectomy, 3 eyes progressing to no light perception. The postoperative visual outcome after vitrectomy for traction retinal detachment in this group of diabetics with a blind fellow eye (mean postoperative visual acuity 0.03 +/- 0.05) was significantly worse (p < 0.000) compared to a group of 196 patients with a seeing fellow eye who were vitrectomized for traction retinal detachment at our clinic (mean postoperative visual acuity 0.09 +/- 0.11). Therefore we conclude that traction retinal detachment in this subgroup of patients is a particularly severe presentation of diabetic retinopathy with a guarded functional prognosis after vitrectomy. Our results demonstrate the importance of timely full scatter photocoagulation and early vitrectomy in eyes with progressive fibrovascular proliferation not responding to panretinal photocoagulation. We conclude that especially diabetic patients with a blind fellow eye must be followed closely and assigned to vitrectomy at an earlier stage of their disease in order to improve functional prognosis.

Vitrectomy for complications of proliferative diabetic retinopathy. Functional outcomes

PURPOSE

To quantitate the effect of diabetic vitrectomy on each patient's visual system and function.

METHODS

The anatomic and visual acuity outcomes of diabetic vitrectomy among three surgeons at one institution over a 4-year time interval were studied. Outcome parameters describing the visual system function were defined and applied to quantitate the effect on visual system disability.

RESULTS

The anatomic and visual success rates and prognostic factors in the cohort of 213 patients by standard statistical analysis were similar to previous studies. The study eye was the eye with better vision in 68 (32%) patients at the conclusion of the study, and vision was equal to the fellow eye in 35 (16%) patients. The mean impairment of the visual system by the American Medical Association Guidelines for Disability was reduced from 61% preoperatively to 50% postoperatively. The factor associated with greatest degree of reduction of impairment of the visual system was a previtrectomy diagnosis of vitreous hemorrhage. There was at least a one-step improvement of visual system function in 65 (31%) patients.

CONCLUSIONS

Vitrectomy for complications of severe proliferative diabetic retinopathy is especially valuable in improving the patient's overall visual function.