Table of contents

Editorial

** From the Department of Ophthalmology at King Hussein Medical Center in Royal Medical Services, uveitis and medical retina specialist, FRCS (glasg), Jordanian board of Ophthalmology.

Correspondence
Dr. Ismat Ereifej,
Department of Ophthalmology at King Hussein Medical Center- Royal Medical Services, Jordanian board of ophthalmology
Tel: 00962777408090

Macular oedema is one of the most important reasons for reduced vision in patients with diabetic retinopathy. If there is focal leakage of fluid in the macular region, it can be treated by focal argon laser coagulation of the leaking retinal area ^1-2. In eyes with diffuse macular oedema, laser treatment cannot be focused on localized retinal leakage spots since the entire macula is involved. This is usually treated with grid laser covering the whole macular region with a fine net of small laser coagulation spots although its benefit is still controversial ³.

The use of sub-Tenon's and intravitreal triamcinolone acetonide for the treatment of diabetic macular oedema has been recently investigated ^3-5. In this study we aimed to compare between the effect of sub-Tenon's (20 mg) and intravitreal triamcinolone acetonide injection (2 mg and 20 mg) on visual acuity and intraocular pressure in management of diffuse macular oedema.

A prospective, comparative, non-randomised clinical interventional study that included 80 patients (eyes) with diffuse diabetic macular oedema attending ophthalmology clinic at King Hussein Medical Center. Patients were randomized to receive either an intravitreal injection of 2 mg triamcinolone acetonide, intravitreal injection of 20 mg triamcinolone acetonide, sub-Tenon's injection of 20 mg triamcinolone acetonide, and a control group that received only laser treatment (20 patients in each group). All patients in the three study groups received laser treatment (focal or grid) one week after the injection. Patients were followed up regularly up to six months. Ophthalmologic examination included Snellen visual acuity testing, anterior segment examination via slit lamp, dilated funduscopy and Goldmann's applanation tonometry. Visual acuity and intraocular pressure were assessed at each visit.

The mean age of all patients was 66.6 years with a 1.1:1 male to female ratio. Patients in different groups were comparable regarding age, presence of cardiovascular disease, renal impairment and hyperlipidaemia. Maximum increase in visual acuity was significantly associated with the 20 mg intravitreal triamcinolone injection followed by 2 mg intravitreal injection. A gain of visual acuity of at least two Snellen lines was seen in 75% and 60% after three months in the two groups respectively. A similar gain was seen in 40% of patients treated with sub-Tenon's triamcinolone and in 5% of the control group. After six months, the figures were 60% for 20 mg intravitreal triamcinolone, 55% for 2 mg intravitreal triamcinolone, 50% for sub-Tenon's injection compared to a drop of the visual acuity in the control group (table 1).

Table 1 Number and percentage of patients with two Snellen line gain in visual acuity after 3 and 6 months of treatment.

Increase in intraocular pressure was not significantly different between the two doses of intravitreal injection and less elevated after sub-Tenon's injection (mean intraocular pressure in control group- 15.6 mmHg, sub-Tenon's triamcinolone- 17.3 mmHg, 2 mg intravitreal triamcinolone- 19.8 mmHg, 20 mg intravitreal triamcinolone- 22.4 mmHg). Elevation of intraocular pressure was maximum two months after the injection. All patients who showed persistent elevation of intraocular pressure responded well to medical treatment (table 2).

Table 2 Intraocular pressure changes after 2 months of treatment and its response to medical treatment when indicated.

Recent clinical and experimental studies have suggested that the intravitreal injection of triamcinolone acetonide may be a therapeutic option for the treatment of intraocular neovascular, oedematous, or inflammatory diseases ^6-7. In case series studies doses of 4 mg or about 20 mg triamcinolone acetonide were used and resulted in a significant increase in visual acuity compared to visual acuity measurements obtained at baseline ^8-10. Our results supported what was previously reported. Three months after the injection, a maximum increase in visual acuity was associated with the 20 mg intravitreal triamcinolone injection followed by 2 mg intravitreal injection. A gain of visual acuity of at least two Snellen lines was seen in 75% and 60% in the two groups respectively. A similar gain was seen in 40% of patients treated with sub-Tenon's triamcinolone and in 5% of the control group. After six months, the figures were 60% for 20 mg intravitreal triamcinolone, 55% for 2 mg intravitreal triamcinolone, 50% for sub-Tenon's injection compared to a drop of the visual acuity in the control group. From these results, we can see that there is no significant difference regarding visual acuity improvement in the three groups, six months after the injection.

None of the study groups showed evidence of endophthalmitis, marked progression of cataract as assessed by slit lamp or retinal detachment. The main side effect of intravitreal triamcinolone acetonide observed in the present study was an increase in intraocular pressure. Intraocular pressure (IOP) was measured after the injection by one day, one week and monthly thereafter. Increase in intraocular pressure was not significantly different between the two doses of intravitreal injection (2 mg intravitreal triamcinolone-19.8 mmHg, 20 mg intravitreal triamcinolone-22.4 mmHg). Less intraocular pressure elevation was seen after sub-Tenon's injection (17.3 mmHg). Elevation of intraocular pressure was maximum two months after the injection. Four patients (20%) of the group that received 20 mg intravitreal triamcinolone needed medical treatment, compared to 2 patients (10%) who received 2 mg intravitreal injection and 1 patient (5%) of the sub-Tenon's group. All patients responded well to medical treatment and none of them needed surgery. Comparative studies showed that 20-50% of patients developed intraocular pressure measurements higher than 21 mm Hg ^11-13. Jonas JB and his colleagues found that the rise of IOP is reversible about 6 months after the injection and is usually controlled by topical antiglaucomatous medication; and that the steroid induced ocular hypertension may thus not be a major contraindication against the use of intravitreal triamcinolone acetonide as treatment trial of intraocular neovascular or oedematous diseases ¹².

In conclusion, there was no significant difference in the final visual acuity in patients with diffuse diabetic macular oedema receiving either sub-Tenon's injection or intravitreal triamcinolone acetonide (2 mg or 20 mg). Sub-Tenon's triamcinolone had the advantage of less intraocular pressure elevation.