The structural effect of intravitreal Brilliant blue G and Indocyanine green in rats eyes.

PURPOSE: To compare the potential retinal toxicity of two commercially Brilliant blue G dyes (Brilliant Peel and Ocublue Plus) and Indocyanine green (ICG) at usual clinical concentration. METHODS: Brilliant Peel 0.025% (n=9), Ocublue Plus 0.025% (n=9), and ICG 0.05% (n=9) were injected intravitreally into Sprague-Dawley rat left eyes with balanced salt solution injected in the contralateral eyes as control. Evaluation of the effect of the dyes on retinal architecture was done by histological analysis of neurosensory retinal thickness and retinal ganglion cell (RGC) counts 7 days after intravitreal injection. Paired t-test was done to detect the presence of biologically significant thinning in neurosensory retina and five retinal layers for each dye (paired t-tests). One-way ANOVA and Tukey's Honestly Significant Difference test were used to assess whether different dyes caused significant thinning in mean neurosensory retinal thickness and reduction of mean RGC density. RESULTS: Eyes treated with ICG had significantly thinner mean total neurosensory retinal thickness compared with the control eyes (P-value=0.01), followed by those treated with Ocublue Plus (P-value=0.03). Brilliant Peel did not cause significant thinning in any of the five retinal layers (all P-values>0.05). No significant difference in mean thinning of the total retinal thickness was detected between dyes (P-value=0.11). The mean thickness of the photoreceptor outer segment and outer plexiform layers were significantly reduced in ICG-injected eyes when compared with the control eyes (P-value=0.02). No significant difference in mean thinning between the three dyes was detected at all five retinal layers using one-way ANOVA (all P-values>0.35). RGC density was significantly reduced for ICG (P-value=0.01) but only marginally for Ocublue Plus (P-value=0.05). No significant reduction in RGC density was observed for Brilliant Peel (P-value=0.2). CONCLUSION: Intravitreal Brilliant Peel is safe to rats retina. The retinal thinning and reduction in RGC density induced by Ocublue Plus requires further studies to determine the safety profile of this product. Potential retinal toxicity is seen with ICG 0.05%.

Lack of association between Gly82Ser, 1704G/T and 2184A/G of RAGE gene polymorphisms and retinopathy susceptibility in Malaysian diabetic patients.

Diabetic retinopathy is the most common diabetic eye disease, occurring in about 60% of type 2 diabetic patients. Other than known clinical risk factors, the influence of genes has been suggested as part of the development of diabetic retinopathy. We investigated the association of Gly82Ser, 1704G/T and 2184A/G polymorphisms in the RAGE gene with retinopathy in type 2 diabetic patients in Malaysia. Ninety-eight unrelated retinopathy patients and 185 unrelated healthy controls from all over Malaysia were recruited in this study. The allele and genotype frequencies of the three gene polymorphisms were investigated using PCR-RFLP. The allele frequency of the three polymorphisms did not differ significantly between the control and the retinopathy group (P > 0.05). Analysis of the frequency of GA+AA, GT+TT and AG+GG in the retinopathy group did not reveal significant differences (P > 0.05) compared to the control group. We conclude that RAGE gene Gly82Ser, 1704G/T and 2184A/G polymorphisms are not associated with retinopathy development in the Malaysian population.

Retinal laser photocoagulation.

Since its discovery in the 1940s, retinal photocoagulation has evolved immensely. Although the first photocoagulators utilised incandescent light, it was the invention of laser that instigated the widespread use of photocoagulation for treatment of retinal diseases. Laser permits choice of electromagnetic wavelength in addition to temporal delivery methods such as continuous and micropulse modes. These variables are crucial for accurate targeting of retinal tissue and prevention of detrimental side effects such as central blind spots. Laser photocoagulation is the mainstay of treatment for proliferative diabetic retinopathy amongst many other retinal conditions. Considering the escalating prevalence of diabetes mellitus, it is important for physicians to grasp the basic principles and be aware of new developments in retinal laser therapy.

Intravitreal injection of recombinant tissue plasminogen activator and pneumatic displacement of submacular haemorrhage.

We report a case of a patient with hypertension and ischaemic heart disease on anti-platelet treatment, who developed uniocular profound visual loss from a submacular haemorrhage secondary to valsalva retinopathy. He was treated with a combination of intravitreal recombinant tissue plasminogen activator (rtPA) and sulphur hexafluoride (SF6) gas followed by strict prone positioning. He demonstrated significant displacement of the haemorrhage and improvement of vision postoperatively.

Photodynamic therapy combined with systemic corticosteroids for choroidal neovascularisation secondary to punctate inner choroidopathy.

AIM: To report on visual acuity (VA) and angiographic outcomes in patients presenting with subfoveal choroidal neovascular membranes (CNV) secondary to punctate inner choroidopathy (PIC), treated with photodynamic therapy (PDT) with verteporfin combined with systemic corticosteroids. METHODS: A prospective case series of patients with subfoveal CNV secondary to PIC was analysed. All patients were treated with PDT combined with oral prednisolone (1 mg/kg body weight/day) which was started 5 days before PDT. Fluorescein angiography was performed at baseline and every 3 months post-treatment to establish the size, position, and activity of the CNV. Visual acuity was measured using the ETDRS scale. Further PDT treatment was carried out at follow-up visits if there was angiographic evidence of ongoing CNV activity. RESULTS: Five female patients with a mean age of 30.4 years (range 25-43 years) were treated over a 12-month period. The mean greatest linear diameter (GLD) of the CNV was 1.66 mm (range 0.46-3.28 mm). A mean improvement in vision of nine ETDRS letters (range -15-20 letters) after treatment was found, which was maintained at final follow-up. The mean follow-up time was 12 months (range 10-14 months). The mean number of PDT treatments was two (range 1-3). CONCLUSIONS: The vaso-occlusive effect of PDT combined with the vasostatic and anti-inflammatory effect of systemic oral prednisolone appears to be a safe and effective option in the primary treatment of subfoveal CNV in patients with PIC.

Retinal artery macroaneurysms: clinical and fluorescein angiographic features in 34 patients.

AIM: To describe the clinical and fluorescein angiographic features of patients with macroaneurysms (MAs) attending an ophthalmology department over 8 years. METHODS: All the patients between 1997 and 2004 with a diagnosis of retinal artery MA were identified from hospital records. Photographs and fluorescein angiograms were examined, and the MAs classified according to their clinical (haemorrhagic or exudative) features, and angiographic (saccular or fusiform) features. Baseline data of the patients were taken including visual acuity and associated ocular and medical conditions. RESULTS: A total of 38 MAs were identified in 34 patients. The age at presentation ranged from 36 to 93 years, with a mean of 73.7 years. Of them, 24/34 (70%) were female patients, and 10/34 (30%) were male patients. There was a history of hypertension in 9/14 patients (64.3%). Of 38 MAs, 32 were identifiable as either saccular or fusiform. Of these, 22/32 (68.75%) were saccular, the rest fusiform. In all, 72.7% of the saccular MAs showed haemorrhage as the predominant feature. Of the 10 fusiform MAs, 90% showed haemorrhage as the predominant feature. CONCLUSION: Retinal artery macroaneurysm is a rare condition that may mimic a variety of other conditions. Most MAs do not require treatment. We suggest guidelines for diagnosis and propose a treatment algorithm for this condition.

Imaging of osteo-odonto-keratoprosthesis by electron beam tomography.

AIM: To describe the experience of using electron beam tomography (EBT) in imaging of osteo-odonto-keratoprosthesis (OOKP) to identify early bone and dentine loss which may threaten the viability of the eye. METHODS: Seven patients with an OOKP in one eye underwent EBT. The OOKP lamina dimensions were measured on EBT and compared to the manual measurements at the time of surgery. RESULTS: There was a high degree of resolution of the OOKP lamina noted with EBT. In particular, it identified three patients with a marked degree of thinning of the lamina edges. Two of these patients had OOKP that were allografts. The mean time from surgery to examination was 3.6 years (range 1.2-5 years) while the mean age of the patients was 56 years (range 31-79 years). CONCLUSIONS: It is important to monitor regularly the dimensions and stability of the OOKP lamina as it will help detect cases that are at risk of extrusion of the optical cylinder and consequent endophthalmitis. Prophylactic measures can then be taken to prevent such serious complications from occurring. In this series, the authors found EBT to have excellent resolution and speed and they would support regular scanning of the OOKP lamina in all patients.

Retrobulbar haemorrhage associated with chronic Gingko biloba ingestion.

Retrobulbar haemorrhage is a rare and potentially sight threatening complication after peribulbar local anaesthetic injection for cataract surgery. A case is reported of a woman who developed this complication and was subsequently found to have been taking Gingko biloba extract tablets which may have predisposed her to developing the haemorrhage.

Does frequency doubling technology perimetry reliably detect neurological visual field defects?

AIM: To determine the ability of frequency doubling technology (FDT) perimetry to detect visual field defects of neurological origin. METHODS: A total of 15 eyes of nine patients who all had complete hemianopias or quadrantanopias underwent the FDT 20-5 screening mode test and Humphrey 24-2 SITA Fast visual field test (HFA). The FDT results were scored according to the number of abnormal test locations (out of a maximum of 4) in each affected quadrant. FDT locations showing a defect of P< 2% were considered abnormal. RESULTS: Of the 15 eyes, six showed complete superior quadrantanopic and nine complete hemianopic field defects on HFA. Of 96 FDT test locations in these quadrants or hemifields only 38 were abnormal on FDT testing (40%). For the quadrantanopic field defects, five out of 24 locations were abnormal (21%). For the hemianopic field defects, 33 out of 72 locations were abnormal (49%). In three eyes (two with quadrantanopias and one with complete hemianopia), FDT perimetry failed to demonstrate any corresponding abnormality. CONCLUSIONS: The FDT screening test can fail to demonstrate complete hemianopic and quadrantanopic field defects. Users should be aware of this deficiency when using FDT to screen for field defects.