The ring sign in patients with pigment epithelial detachments.

Four patients with pigment epithelial detachment due to age-related macular degeneration underwent clinical examination and optical coherence tomography (OCT) scan. A ring-shaped pattern on the fast retinal thickness maps of the OCT was observed for all of these patients with little central retinal thickness but increasing retinal thickness at the edge of the pigment epithelial detachment. The authors have coined the term "ring sign" to describe this pattern typically seen on the OCT scan in patients with pigment epithelial detachment with or without underlying choroidal neovascularization.

Diabetes and the tortuosity of vessels of the bulbar conjunctiva.

OBJECTIVES: Diabetes is associated with loss of capillaries and macrovessel dilation in the conjunctiva, similar to well-known vessel changes in the retina. However, little is known about the effect of diabetes on the tortuosity of vessels of the conjunctiva. The authors examined the tortuosity of conjunctival vessels in participants with and without diabetes. DESIGN: Case-control study. PARTICIPANTS AND CONTROLS: Fifty-three patients with diabetes (17 with type 1 diabetes, 36 with type 2 diabetes) and 60 controls (all aged 20-94 years). METHODS: Digital red-free images of conjunctivae were analyzed using an automated computer algorithm to identify vessel axes and to quantify vessel tortuosity. Differences in vessel tortuosity were adjusted for age, gender, blood pressure, and smoking status. MAIN OUTCOME MEASURES: Tortuosity was expressed in units of curve energy (the square of the radian angular change between subsequent locations identified by the algorithm, standardized by vessel length). RESULTS: A longer duration of diabetes was associated with a reduction in overall vessel tortuosity (-2.8%; 95% confidence interval [CI], -4.3% to -1.3% per decade). This inverse association was driven by changes in larger vessels (40 microm in width or more), whereas increased tortuosity was observed in capillary sized vessels (<25 microm, 4.0%; 95% CI, -0.2% to 8.2% per decade). Compared with controls, those with type 1 diabetes (median duration of disease, 26 years) showed a 17.9% increase (95% CI, 4.7% to -31.0%) in capillary tortuosity. Conversely, those with type 1 diabetes showed a 7% decrease (95% CI, -11.8% to -2.3%) in tortuosity among vessels 40 to 80 microm or less in size and a 26.8% decrease (95% CI, -66.2% to 12.7%) in the fewer number of vessels more than 80 microm in size compared with controls. Similar, but smaller differences were seen in those with type 2 diabetes with shorter duration of diabetes (median, 7 years). CONCLUSIONS: Macrovessel dilation associated with diabetes may result in vessel engorgement and straightening, especially among those with longer durations of disease. Increased tortuosity associated with diabetes among conjunctival capillaries mirrors established vessel changes observed in the retina. Conjunctival angiopathy associated with diabetes may contribute to susceptibility to anterior eye disease among patients with diabetes.

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.

Combined phacovitrectomy for macular hole: long-term results.

BACKGROUND AND OBJECTIVE: To present the long-term results of patients undergoing combined phacovitrectomy surgery for idiopathic macular hole at a single center. PATIENTS AND METHODS: A retrospective review of the records for 57 eyes of 53 consecutive patients who underwent combined phacovitrectomy for idiopathic macular hole during an 18-month period was completed at the Southampton Eye Unit. RESULTS: In 45 of 57 eyes (78.9%), the macular hole closed after one surgical procedure. Forty-seven patients had a follow-up period of more than 12 months (mean = 22.1 months). In this group, the mean visual acuity (standard deviation) improved by 0.37 (+/- 0.46) logarithm of the minimum angle of resolution units. Thirty-two (68%) cases had improved visual acuity of 2 or more Snellen lines. Hole closure rate at the final follow-up examination was 87.2%. CONCLUSION: Combining phacoemulsification and vitrectomy for an idiopathic macular hole has many benefits. It is a safe procedure and produces long-term results that are comparable to previously published series.

Vascular response of the bulbar conjunctiva to diabetes and elevated blood pressure.

OBJECTIVE: Retinovascular changes associated with diabetes have been clearly documented; changes in vessels of the conjunctiva are less well described. We examined changes in conjunctival vessel morphologic features in participants with and without diabetes. DESIGN: Case-control study. PARTICIPANTS AND CONTROLS: Fifty-three patients with diabetes (17 with type 1 diabetes, 36 with type 2 diabetes) and 60 controls (all aged 20-94 years). METHODS: Digital red-free conjunctival images were captured and an automated computer algorithm was used to derive indices that describe the morphologic features of vessels of the conjunctiva. Percentage differences in vessel indices were adjusted for age, gender, blood pressure, and smoking status. MAIN OUTCOME MEASURES: Mean vessel diameter (micrometers) and vessel density (square millimeters of vessel per square centimeter of bulbar conjunctiva). RESULTS: A strong positive association between the duration of diabetes and overall mean vessel width was observed (P<0.001), resulting from changes in larger vessels (>80 mum in width). Conversely, the duration of diabetes showed a strong inverse association with vessel area (P<0.001) that appeared to be driven by the trend observed in smaller vessels (<40 mum in width). A 25% reduction (95% confidence interval [CI], -35% to -13%; P<0.001) in vessel density in those with type 1 diabetes and a 14% reduction (95% CI, -24% to -3%; P = 0.016) in those with type 2 diabetes, compared with controls, was observed. Mean vessel widths were 11% (95% CI, 4%-17%; P = 0.001) wider in type 1 and 5% (95% CI, 0%-10%; P = 0.073) wider in those with type 2 diabetes compared with controls. The difference in magnitude of effect for type 1 and type 2 diabetes compared with controls was explained by duration of diabetes. Grade of diabetic retinopathy and elevated blood pressure showed similar but less strong associations with vessel indices. CONCLUSIONS: Loss of capillaries and macrovessel dilation in the conjunctiva associated with diabetes compares with well-known vessel changes in the retina. Associations between morphologic changes in the conjunctiva and elevated blood pressure were similar but less strong; this may show that diabetic angiopathy predominates in those with both diabetes and elevated blood pressure.

Sudden visual loss after removal of silicone oil.

PURPOSE: Removal of silicone oil after vitreoretinal surgery reduces potential complications of glaucoma and cataract and improves visual function in 30% of patients. We report the clinical findings of a series of patients who experienced unexpected and permanent visual loss after removal of silicone oil. METHODS: Seven patients with visual loss after removal of silicon oil were investigated with best-corrected Snellen visual acuity (BCVA) assessment, fundus biomicroscopy, fluorescein angiography, optical coherence tomography, and electrophysiologic examination. RESULTS: Six men and one woman (average age, 42.8 years.) presented with profound BCVA loss, averaging 4.7 Snellen lines (SD 1.4), after silicon oil removal. No other complications associated with oil removal were noted. The retina remained attached in all cases, no patient developed cystoid macular edema or epiretinal membrane, and optical coherence tomographic and fluorescein angiographic findings remained normal. Electrodiagnostic testing showed a range of abnormalities, with the majority of patients showing severe macular dysfunction. CONCLUSIONS: We describe a new phenomenon of unexpected visual loss after oil removal in patients with good visual potential. The pathogenesis remains obscure.

Screening for sight-threatening diabetic retinopathy: comparison of fundus photography with automated color contrast threshold test.

PURPOSE: To compare tritan contrast threshold (TCT) with fundus photography in screening for sight-threatening diabetic retinopathy (STDR), before significant visual loss. DESIGN: Prospective, comparative study. METHODS: A total of 510 consenting diabetic patients attending a hospital-based photographic screening clinic were recruited over a 2-year period. Exclusion criteria included visual acuity of worse than 6/9, previous photocoagulation, and a history of previous eye disease known to affect color vision. The automated TCT test was performed using a computerized cathode ray tube-based technique. Retinal photography was performed using a Polaroid mydriatic fundus camera with a 45 degrees field. Grading of diabetic retinopathy was carried out by an ophthalmologist using slit-lamp biomicroscopy and a 78-diopters lens. Assessments of sensitivity, specificity, and predictive values for both fundus photography and the TCT test were made. RESULTS: Both the fundus photography and TCT test correlated significantly with the presence of STDR (P <.0001, chi(2) test). The TCT test yielded a sensitivity of 94% (95% confidence interval [CI], 73%- 100%) and a specificity of 95% (95% CI, 92%- 96%) for detection of STDR compared with a sensitivity of 88% (95% CI, 66%-97%) and a specificity of 95% (95% CI, 93%-97%) with fundus photography. Combined modality improved overall screening performance. CONCLUSION: The TCT assessment is an effective and clinically viable technique, in comparison with fundus photography, to screen for STDR among a diabetic population. Additionally, our results also showed that combining the TCT test with fundus photography greatly increases the performance of screening for STDR.

Large spot endolaser for retinal photocoagulation and transvitreal thermotherapy.

BACKGROUND AND OBJECTIVE: Diode laser transpupillary thermotherapy can be used for the treatment and choroidal tumors. A large spot endolaser probe was developed for endophotocoagulation and transvitreal thermotherapy. The aim of this study was to assess the probe's clinical performance for photocoagulation and transvitreal thermotherapy combined with macular elevation. MATERIALS AND METHODS: Endolaser with a divergent beam giving a 3 mm spot size on the retina was developed. Vitrectomy was performed on ten eyes of five Dutch Belted rabbits. Threshold for photocoagulation was determined for the diode (810 nm) laser in four eyes. In another six eyes, the retina was detached with balanced salt solution prior to laser irradiation. The tissue effects were monitored clinically and with photography and microscopy. RESULTS: Threshold photocoagulation was induced with 150 mW power, for 1 minute, in attached retina. Following retinal detachment, no coagulation occurred at 200 mW (suprathreshold) power for 1 minute. CONCLUSIONS: A large spot endolaser probe may be useful for endophotocoagulation. It generates more gradual photocoagulation than standard endolaser probes, giving a more controllable reaction over a larger area. This may be useful for treatment of large areas of the retina when treating retinal detachments or ischemic retinopathies. When detached retina was irradiated, no retinal damage occurred at suprathreshold power. This development may allow for intraoperative transvitreal thermotherapy of choroidal neovascularization while protecting the retina with intentional intraoperative detachment of the retina.