Adaptations in aquatic organisms for increased sensitivity to light and differences from humans.

The retina of aquatic organisms has been adapted, through evolution, to the specific lighting conditions of water. The purpose of this paper is to present the major morphological and functional differences of photoreceptors between humans and aquatic organisms. Comparison of visual pathways of the nervous system between humans and aquatic organisms is also attempted.

Safety of 20-gauge transconjunctival sutureless vitrectomy.

PURPOSE: To study the safety of 20-gauge transconjunctival sutureless vitrectomy. METHODS: Clinical data of patients who underwent 20-gauge transconjunctival sutureless vitrectomy for the first time, for various disorders, were reviewed retrospectively. The main outcome measures were the number of sclerotomies requiring suturing as well as the intra- and postoperative complications. RESULTS: A total of 179 operations were performed. Indications for vitrectomy included 68 idiopathic epiretinal membranes, 26 macular holes, 23 phakic and 16 pseudophakic retinal detachments, and 46 various other, less common etiologies. Of these 179 operations, 166 (93%) were sutureless. Of the 537 sclerotomies created, 25 (5%) received a single transconjunctival-scleral suture. Intraoperative complications included premature dislodging of the cannulas in 2 sclerotomies and an iatrogenic horseshoe tear at 1 sclerotomy site. Postoperative complications comprised transient hypotony in 14 cases, subconjunctival gas in 2 cases, and choroidal effusion in 1 case. No serious complications (such as endophthalmitis) were observed. CONCLUSION: 20-gauge transconjunctival sutureless vitrectomy can be considered safe, as the intra- and postoperative complications observed are neither numerous nor significant. Sclerotomies appear to be safe and relatively easy to perform, without compromising the advantages of sutureless surgery.

Effect of ranibizumab on serous and vascular pigment epithelial detachments associated with exudative age-related macular degeneration.

PURPOSE: To report the effect of intravitreal ranibizumab therapy for serous and vascular pigment epithelial detachments (PED) associated with choroidal neovascularisation (CNV) secondary to age-related macular degeneration (AMD). METHODS: In a prospective study, best-corrected visual acuity (BCVA) and optical coherence tomography (OCT) data were collected for 62 eyes of 62 patients, with serous or vascular PED associated with CNV secondary to AMD. Intravitreal ranibizumab 0.5 mg was administered with a loading phase of three consecutive monthly injections, followed by monthly review with further treatment, as indicated according to the retreatment criteria of the PrONTO study. The change in visual acuity and PED height from baseline to month 12 after the first injection was determined. RESULTS: Sixty-one eyes of 61 patients (one of the patients developed retinal pigment epithelial tear and was excluded from the study) were assessed at the 12-month follow-up examination. There were two types of PED, including vascular PED in 32 patients (Group A) and serous PED (Group B) in 29 patients. The mean improvement of mean BCVA from baseline to 12 months was 0.09 logMAR (Logarithm of the Minimum Angle of Resolution) in Group A and 0.13 logMAR in Group B. Both groups showed significant improvement of the mean BCVA 12 months after the first injection compared with the baseline value (P < 0.05). In relation to the PED height, the mean decrease of mean PED height from baseline to 12 months was 135 µm in Group A and 180 µm in Group B. Both groups showed significant reduction of the PED height during the follow-up period (P < 0.01). The PED anatomical response to ranibizumab was not correlated with the BCVA improvement in any of the groups. Apart from one patient who developed pigment epithelial tear no other complications were documented. CONCLUSION: Ranibizumab is an effective and safe treatment for improving vision in patients with serous and vascular PED, although the anatomical response of the PED to ranibizumab may not correlate directly with the visual outcome.

Preretinal partial pressure of oxygen gradients before and after experimental pars plana vitrectomy.

PURPOSE: To evaluate preretinal partial pressure of oxygen (PO2) gradients before and after experimental pars plana vitrectomy. METHODS: Arteriolar, venous, and intervascular preretinal PO2 gradients were recorded in 7 minipigs during slow withdrawal of oxygen-sensitive microelectrodes (10-µm tip diameter) from the vitreoretinal interface to 2 mm into the vitreous cavity. Recordings were repeated after pars plana vitrectomy and balanced salt solution (BSS) intraocular perfusion. RESULTS: Arteriolar, venous, and intervascular preretinal PO2 at the vitreoretinal interface were 62.3 ± 13.8, 22.5 ± 3.3, and 17.0 ± 7.5 mmHg, respectively, before vitrectomy; 97.7 ± 19.9, 40.0 ± 21.9, and 56.3 ± 28.4 mmHg, respectively, immediately after vitrectomy; and 59.0 ± 27.4, 25.2 ± 3.0, and 21.5 ± 4.5 mmHg, respectively, 2½ hours after interruption of BSS perfusion. PO2 2 mm from the vitreoretinal interface was 28.4 ± 3.6 mmHg before vitrectomy; 151.8 ± 4.5 mmHg immediately after vitrectomy; and 34.8 ± 4.1 mmHg 2½ hours after interruption of BSS perfusion. PO2 gradients were still present after vitrectomy, with the same patterns as before vitrectomy. CONCLUSION: Preretinal PO2 gradients are not eliminated after pars plana vitrectomy. During BSS perfusion, vitreous cavity PO2 is very high. Interruption of BSS perfusion evokes progressive equilibration of vitreous cavity PO2 with concomitant progressive return of preretinal PO2 gradients to their previtrectomy patterns. This indicates that preretinal diffusion of oxygen is not altered after vitrectomy. The beneficial effect of vitrectomy in ischemic retinal diseases or macular edema may be related to other mechanisms, such as increased oxygen convection currents or removal of growth factors and cytokines secreted in the vitreous.

The rationale of retinal endovascular fibrinolysis in the treatment of retinal vein occlusion: from experimental data to clinical application.

PURPOSE: We describe a retinal endovascular fibrinolysis technique to directly reperfuse experimentally occluded retinal veins using a simple micropipette. METHODS: Retinal vein occlusion was photochemically induced in 12 eyes of 12 minipigs: after intravenous injection of 10% fluorescein (1-mL bolus), the targeted retinal vein segment was exposed to thrombin (50 units) and to Argon laser (100-200 mW) through a pars plana approach. A beveled micropipette with a 30-µm-diameter sharp edge was used for micropuncture of the occluded vein and endovascular microinjection of tissue plasminogen activator (50 µg/mL) in 11 eyes. In one control eye, balanced salt solution was injected. The lesion site was examined histologically. RESULTS: Retinal vein occlusion was achieved in all cases. Endovascular microinjection of tissue plasminogen activator or balanced salt solution led to reperfusion of the occluded retinal vein in all cases. Indicative of successful reperfusion were the following: continuous endovascular flow, unaffected collateral circulation, no optic disk ischemia, and no venous wall bleeding. However, balanced salt solution injection was accompanied by thrombus formation at the punctured site, whereas no thrombus was observed with tissue plasminogen activator injection. CONCLUSION: Retinal endovascular fibrinolysis constitutes an efficient method of micropuncture and reperfusion of an experimentally occluded retinal vein. Thrombus formation at the punctured site can be prevented by injection of tissue plasminogen activator.

Retinal vessel diameter can reliably be determined in minipigs using Retinal Vessel Analyser with a microscope-mounted fundus camera.

PURPOSE: Retinal Vessel Analyser (RVA) is a validated instrument to measure retinal vessel diameter in humans. The purpose of this study was to assess the reproducibility (inter-observer reliability) and the repeatability (test-retest reliability) of RVA with a microscope-mounted fundus camera to determine retinal vessel diameter in minipigs. METHODS: Ocular fundus image from five anaesthetized minipigs was recorded in a digital videotape for approximately 5 min, under stable systemic arterial pressure and gas conditions. To evaluate the reproducibility, each one of two investigators used RVA to measure the diameter of the superior temporal retinal artery on five separate 30-second video sequences from each minipig, which were the same video sequences for both investigators. To evaluate the repeatability, one investigator performed five measurements on a single, randomly selected, 30-second video sequence from each minipig. The reproducibility was determined using the intra-class correlation coefficient (ICC), and the repeatability was assessed using the coefficient of variation (COV). Bland-Altman plots were also used to assess agreement between the two investigators. RESULTS: Retinal arteriolar diameter measurements with RVA in minipigs were highly reproducible. Differences between the two investigators were lower than 0.7%. The ICC was 1.00, indicating perfect reproducibility, and the mean COV was 0.18%, reflecting excellent repeatability of the measurements with RVA. CONCLUSION: Retinal vessel diameter can reliably be determined not only in humans, but also in minipigs, using the commercially available RVA apparatus and a microscope-mounted fundus camera.

Idiopathic macular epiretinal membrane surgery and ILM peeling: anatomical and functional outcomes.

PURPOSE: Evaluation of the visual and anatomical outcomes following idiopathic macular epiretinal membrane (ERM) removal, with or without internal limiting membrane (ILM) peeling, and review of the literature. METHODS: A retrospective study of 39 eyes operated for idiopathic ERM was conducted. Pars plana vitrectomy was combined with ERM removal and Indocyanine green (ICG) assisted ILM peeling in 24 eyes. RESULTS: In Group A (without ILM peeling), mean preoperative BCVA was 0.48 logMAR (0.3 in decimal units), whereas mean postoperative BCVA was 0.37 logMAR (0.4 in decimal units). In Group B (with ILM peeling), mean preoperative BCVA was 0.58 logMAR (0.25 in decimal units), whereas mean postoperative BCVA was 0.31 logMAR (0.5 in decimal units). No statistically significant difference was observed between Groups A and B regarding preoperative or postoperative BCVA (p>0.1, Student's t-test). OCT measurement of postoperative foveal thickness reveled a significant decrease in thickness in both groups; however, no correlation was observed between postoperative BCVA and postoperative foveal thickness (Pearson's correlation coefficient = 0.139; p>0.1). CONCLUSIONS: In spite of final visual acuity improvement following idiopathic ERM removal, recovery of a normal foveal thickness is not achieved in the majority of the cases. ICG assisted ILM peeling does not affect the functional outcome of idiopathic ERM removal.

Vasomotor effect of intravitreal juxta-arteriolar injection of L-lactate on the retinal arterioles after acute branch retinal vein occlusion in minipigs.

PURPOSE: To investigate the effect of L-lactate on retinal arteriolar diameter after acute branch retinal vein occlusion (BRVO) in minipigs. METHODS: Thirteen eyes of 13 minipigs were evaluated, with the animals under general anesthesia. BRVO was induced by a standard method of argon laser endophotocoagulation. Two hours after BRVO, an intravitreal, juxta-arteriolar microinjection of 50 µL L-lactate 0.5 M (pH 7.4) was performed in nine eyes. Four eyes received a microinjection of 50 µL of the solvent (pH 7.4) that was used to prepare the solution of L-lactate and served as controls. Retinal arteriolar diameter changes were measured using a retinal vessel analyzer. RESULTS: Overall (n = 13), 2 hours after BRVO, there was a 9.0% ± 1.4% decrease in the retinal arteriolar diameter in the affected ares compared to baseline (P < 0.001). An increase of 26.2% ± 8.2% (P = 0.004) of the arteriolar diameter was evidenced 5 minutes after L-lactate juxta-arteriolar microinjection (n = 9) compared with the diameter before L-lactate microinjection. Thereafter, the vasodilatory effect of L-lactate persisted and remained significant until the end of the study period (27.7% ± 7.8% at 30 minutes) compared with the diameter before L-lactate microinjection (P = 0.002). Microinjection of the solvent alone (n = 4) did not produce any significant effect on the retinal arterioles, which remained constricted at all time-points (P > 0.1). CONCLUSIONS: These findings demonstrate a significant arteriolar vasodilation after intravitreal juxta-arteriolar L-lactate microinjection in eyes with experimental BRVO in the affected areas. L-lactate microinjection can reverse the arteriolar vasoconstriction that occurs in acute experimental BRVO.

Pars plana vitrectomy in the treatment of severe complicated toxoplasmic retinochoroiditis.

PURPOSE: To present the anatomic and functional results of pars plana vitrectomy performed in severe complicated toxoplasmic retinochoroiditis. METHODS: Three patients, 2 women and 1 man aged 57, 22, and 57 years, are presented. The first patient was under immunosuppressive therapy for dermatomyositis and underwent diagnostic/therapeutic vitrectomy for severe toxoplasmic panuveitis with dense vitritis. The other 2 patients underwent vitrectomy for macula-off rhegmatogenous retinal detachment that developed after severe toxoplasmic panuveitis. RESULT: Preoperative visual acuity was hand movement for the first 2 patients and 20/400 for the third. All patients received pars plana vitrectomy with epiretinal membrane peeling, laser photocoagulation, and SF6 gas tamponade. The second and third patients needed 5 and 3 additional operations, respectively, including extensive retinotomies and silicone-oil tamponade, for recurrent retinal detachment due to proliferative vitreoretinopathy. At the end of the follow-up period (11, 5, and 1 year, respectively), the retina was attached and visual acuity was 20/30 for the first patient but counting fingers for the other 2 patients. CONCLUSIONS: Severe panuveitis and/or recurrent retinal detachment may develop in some cases of ocular toxoplasmosis, compromising the visual prognosis. Retinal detachment due to toxoplasmosis is generally complex, and long-acting tamponade with silicone oil should be contemplated for anatomic retinal reattachment.

The vasodilatory effect of juxta-arteriolar microinjection of endothelinA receptor inhibitor in healthy and acute branch retinal vein occlusion minipig retinas.

Purpose. To investigate the effect of the endothelin(A) receptor inhibitor BQ-123 on the retinal arteriolar vasculature in minipig retinas in normal eyes and eyes with acute branch retinal vein occlusion (BRVO). Methods. Seven healthy eyes of seven minipigs and six eyes of six minipigs with experimental BRVO were evaluated under systemic anesthesia. An intravitreal juxta-arteriolar microinjection of 30 microL BQ-123 0.61 microg/mL (pH 7.4) was performed in all but one eye from each group, into which the physiologic saline vehicle alone was injected. Vessel-diameter changes were measured with a retinal vessel analyzer. Results. In healthy minipig retinas (n = 6), arteriolar diameter (+/-SD) increased 6.19% +/- 3.55% (P < 0.05), 25.98% +/- 2.37% (P < 0.001), 23.65% +/- 1.2% (P < 0.001), and 16.84% +/- 1.95% (P < 0.001), at 1, 5, 10, and 15 minutes, respectively, after BQ-123 microinjection. Two hours after experimental BRVO (n = 5), the retinal arteriolar diameter had decreased (13.07% +/- 5.7%; P < 0.01). One, 5, 10, and 15 minutes after BQ-123 microinjection, retinal arteriolar diameter had increased by 7.14% +/- 3.3% (P < 0.01), 26.74% +/- 7.63% (P < 0.001), 23.67% +/- 6.4% (P < 0.001), and 16.09% +/- 3.41% (P < 0.001), respectively. Vehicle only injection had no vasoactive effect on physiologic or BRVO retinas. Conclusions. A significant increase in retinal arteriolar diameter was demonstrated after juxta-arteriolar BQ-123 microinjection in healthy and in acute BRVO minipig retinas. The results suggest a role for endothelin-1 in maintaining retinal basal arteriolar tone. Reversing the BRVO-related vasoconstriction by juxta-arteriolar BQ-123 microinjection could bring a new perspective to the management of BRVO.

Increased protein carbonylation of red blood cell membrane in diabetic retinopathy.

We investigated the protein carbonylation of red blood cell (RBC) membrane in type 2 diabetic patients and the potential implication of carbonyl/oxidative stress in reflecting disease severity. Sixty-four diabetic patients with or without retinopathy of variable clinical severity (Groups DR and DM, respectively) and 20 healthy controls were included in the study. Protein carbonyls were determined in RBC membranes by immunoblotting. Compared to healthy volunteers, the RBC membranes of diabetic patients were characterized by significantly increased levels of carbonylated proteins. The carbonylation of Group DR was higher compared to that of Group DM. The subgroup of patients with proliferative retinopathy exhibited a trend towards a significant increase in protein carbonyls, compared to both free-of-retinopathy diabetic cases and non-proliferative diabetic retinopathy cases. The correlation between the chemical modifications of the erythrocyte membrane proteins and the clinical severity of diabetic retinopathy suggests a potential utility of membrane carbonylation as a marker and risk factor in the development of retinopathy.

Apoptotic mechanisms within the retina in Staphylococcus epidermidis experimental endophthalmitis.

AIM: To investigate the potential involvement of apoptosis and its regulators Bcl-2, Bax, and Fas within the retina in Staphylococcus epidermidis experimental endophthalmitis. METHODS: Endophthalmitis was induced in 48 male Lewis rats by unilateral 25-mircrol intravitreal injection of 7,000 viable organisms of slime-producing S. epidermidis strain ATCC 35983 (experimental group). Forty-eight other Lewis rats received a similar sterile normal saline injection (control group). The injected eyes were graded for clinical inflammation and were removed in groups at 6, 12, 24, 48, 72, and 168 hours post-injection. After surgical separation, retinal tissue specimens were fixed, and paraffin sections underwent hematoxylin-eosin staining, immunohistochemistry against Bcl-2, Bax, and Fas, and TUNEL assay for detection of apoptotic cells. Following morphometric analysis, the apoptotic body index (ABI) was calculated. RESULTS: While Bcl-2 expression was absent, Bax and Fas expression and apoptosis in ganglion cells, bipolar cells, and photoreceptors, were significantly higher in the experimental group compared to the control group (P < 0.05). In the experimental group, inflammation peaked at 24 hours, Bax and Fas expression at 48 hours and the ABI at 72 hours post-injection. CONCLUSION: Apoptosis is increased within the retina in S. epidermidis experimental endophthalmitis through upregulation of Bax and Fas, peaking soon after peak inflammation.

Effect of systemic nitric oxide synthase inhibition on optic disc oxygen partial pressure in normoxia and in hypercapnia.

PURPOSE: To investigate the effect of systemic nitric oxide synthase (NOS) inhibition on optic disc oxygen partial pressure (PO(2)) in normoxia and hypercapnia. METHODS: Intervascular optic disc PO(2) was measured in 12 anesthetized minipigs by using oxygen-sensitive microelectrodes placed <50 microm from the optic disc. PO(2) was measured continuously during 10 minutes under normoxia, hyperoxia (100% O(2)), carbogen breathing (95% O(2), 5% CO(2)), and hypercapnia (increased inhaled CO(2)). Measurements were repeated after intravenous injection of N(omega)-nitro-L-arginine methyl ester (L-NAME) 100 mg/kg. Intravenous L-arginine 100 mg/kg was subsequently given to three animals. RESULTS: Before L-NAME injection, an increase was observed in optic disc PO(2) during hypercapnia (DeltaPO(2) = 3.2 +/- 1.7 mm Hg; 18%; P = 0.001) and carbogen breathing (DeltaPO(2) = 12.8 +/- 5.1 mm Hg; 69%; P < 0.001). Optic disc PO(2) in normoxia remained stable for 30 minutes after L-NAME injection (4% decrease from baseline; P > 0.1), despite a 21% increase of mean arterial pressure. Optic disc PO(2) increase under hypercapnia was blunted after L-NAME injection (DeltaPO(2) = 0.6 +/- 1.1 mm Hg; 3%; P > 0.1), and this effect was reversible by L-arginine. Moreover, L-NAME reduced the response to carbogen by 29% (DeltaPO(2) = 9.1 +/- 4.4 mm Hg; 49%; P = 0.01 versus before L-NAME). The response to hyperoxia was not affected. CONCLUSIONS: Whereas systemic NOS inhibition did not affect optic disc PO(2) in normoxia, a blunting effect was noted on the CO(2)-induced optic disc PO(2) increase. Nitric oxide appears to mediate the hypercapnic optic disc PO(2) increase.

Lactate-induced retinal arteriolar vasodilation implicates neuronal nitric oxide synthesis in minipigs.

PURPOSE: To investigate the role of neuronal nitric oxide (NO) synthesis in the retinal vasodilatory response to lactate in minipigs. METHODS: Thirteen eyes of 13 minipigs were evaluated. Ten eyes received an intravenous infusion of N(omega)-nitro-L-arginine methyl ester (L-NAME). After 1 hour, the same eyes received an intravitreous juxta-arteriolar microinjection of 30 microL of L-lactate 0.5 M (pH 7.4) through a micropipette. Ten minutes later, 9 of 10 eyes received an intravitreous juxta-arteriolar microinjection of 30 microL of L-NAME 0.01 M (pH 7.4), and 1 received physiologic saline solution (PSS). The remaining three eyes received a microinjection of 30 microL of L-lactate 0.5 M (pH 7.4), without intravenous or intravitreous L-NAME. RESULTS: The three eyes that received juxta-arteriolar injection of L-lactate only showed a reproducible increase in retinal arteriolar diameter that persisted during the entire study period (maximum effect at 20 minutes, 40.9% +/- 3.2%). Retinal arteriolar diameter decreased by 4.1% 1 hour after intravenous L-NAME when compared with baseline but the difference did not reach significance. The juxta-arteriolar injection of L-lactate induced a significant increase in retinal arteriolar diameter (22.7% and 28.7% at 5 and 10 minutes, respectively; P < 0.01), followed by a significant decrease (8.6%; P < 0.01) 10 minutes after juxta-arteriolar injection of L-NAME. Injection of PSS had no effect on retinal arteriolar diameter. CONCLUSIONS: Juxta-arteriolar administration of L-lactate induced vasodilation, which was also observed with continuous intravenous infusion of L-NAME. Moreover, juxta-arteriolar L-NAME microinjection significantly suppressed the vasodilatory effect of L-lactate. These data suggest that neuronal-derived NO is an important mediator of lactate-induced vasodilation in minipigs.

The effect of nasal steroid administration on intraocular pressure.

The effect of systemic steroid administration on intraocular pressure (IOP) is well established. However less attention has been paid to the effect of steroids when administered in a nasal spray. We conducted a study to investigate a possible association between nasal steroids and elevated IOP in 54 patients who were being treated for allergic rhinitis. IOP was measured before the patients started therapy and thereafter every 5 days during that therapy. Follow-up ranged from 27 to 35 days (mean: 31). Statistical analysis revealed no significant elevation in IOP after nasal steroid administration. It seems that short-term administration of nasal steroids does not cause significant IOP elevation. Nevertheless, their long-term effects on this pressure should be investigated.

Optical coherence tomography and multifocal electroretinogram findings in chronic solar retinopathy.

PURPOSE: To correlate the structural and functional retinal defects, which are induced photochemically in chronic solar retinopathy. DESIGN: Observational case report. METHODS: Four emmetropic eyes of two patients, previously diagnosed with chronic solar retinopathy, were evaluated by optical coherence tomography (OCT), multifocal electroretinography, and fluorescein angiography. RESULTS: Visual acuity ranged from 20/80 to 20/50 and all subjects had central and steady fixation. In all eyes, OCT demonstrated a hyporeflective space at the level of outer retinal and retinal pigment epithelium (RPE) layers, which was limited to the fovea. The foveal contour was preserved with normal vitreoretinal interface. Multifocal electroretinogram (mfERG) trace array of the first-order kernel demonstrated attenuated responses extending to a larger area, the para- and perifovea. A foveal RPE window defect was angiographically evident in all cases. CONCLUSIONS: A model of centrifugal neuronal damage is proposed for chronic solar retinopathy, with more functional than structural neuroretinal defects.

Structural alterations of the erythrocyte membrane proteins in diabetic retinopathy.

BACKGROUND: Several rheological disorders of the erythrocytes, such as increased aggregation and decreased deformability, have been observed in diabetes mellitus and have been implicated in the development of diabetic microangiopathy. Structural alterations of the erythrocyte membrane proteins caused by the diabetic process may be at the origin of those observations. In the present study, we searched for erythrocyte membrane protein alterations in diabetic retinopathy. METHODS: We examined peripheral blood samples from 40 type-2 diabetic patients with diabetic retinopathy of variable severity (19 males and 21 females, mean age 66.8 years, Group A) and we compared them with samples from 19 type-2 diabetic patients without diabetic retinopathy (13 males and six females, mean age 66.5 years, Group B) and 16 healthy volunteers (eight males and eight females, mean age 65.6 years, Group C). Erythrocyte membrane ghosts from all samples were subjected to SDS-PAGE, and the electrophoretic pattern of transmembrane and cytoskeletal proteins was analysed for each sample. The protein quantification of each electrophoretic band was accomplished through scanning densitometry. RESULTS: No significant deviations from normal electrophoresis were observed in Groups B and C, apart from an increase in band 8 in two samples from Group B (11%). In contrast, in 14 samples from Group A (35%) we detected increases in protein band 8 and/or membrane-bound haemoglobin along with a decrease in spectrin. Moreover, increased mobility of band 3, an aberrant high molecular weight (MW) (> 255 kDa) band and a low MW (42 kDa) band were evident in ten samples from Group A (25%). Glycophorins were altered in 46% of Group-A patients versus 38% of Group-B patients. Females and patients with long duration of diabetes presented more electrophoretic abnormalities. CONCLUSIONS: Structural alterations of the erythrocyte membrane proteins are shown for the first time in association with diabetic retinopathy. Their detection may serve as a blood marker for the development of diabetic microangiopathy. Further studies are needed to assess whether pharmaceutical intervention to the rheology of erythrocytes can prevent or alleviate microvascular diabetic complications.

Severe bilateral central serous chorioretinopathy in a black patient: 16 years follow-up.

PURPOSE: To describe the exceptionally severe, bilateral, sight-compromising course of central serous chorioretinopathy (CSC) in a black patient. DESIGN: Observational case report. METHODS: We reviewed the clinical and angiographic findings of a 50-year-old black male patient with severe bilateral chronic CSC. RESULTS: The first attack was recorded 16 years earlier and it was asymmetrical. In OD, only retinal pigment epithelium (RPE) alterations were detected, while in OS there was a large serous retinal detachment with two smaller RPE detachments. Visual acuity (VA) was 1.0 OD and 0.6 OS. Gradually, after multiple remissions and exacerbations, a huge area of atrophy occupied the posterior pole OS, leading to a dramatic decrease of VA (0.02). The lesions also progressed and remained active in OD (VA 0.2). CONCLUSIONS: CSC can be exceptionally severe, non-benign, sight-compromising, with multiple remissions and exacerbations during the lifetime. Indocyanine-green angiography is useful for the long-term follow-up in severe cases, showing lesions that are not obvious in fluorescein angiography or funduscopy.