The effects of excitatory amino acids and their transporters on function and structure of the distal retina in albino rabbits.

PURPOSE: To study the physiological and pathological roles of excitatory amino acid transporters in the distal retina of albino rabbits. METHODS: Albino rabbits were injected intravitreally in one eye with different doses of L- or D-isomers of glutamate or aspartate, with mixtures of L-glutamate and antagonists to glutamate receptors or with inhibitors of glutamate transporters. The other eye was injected with saline, and served as a control. The electroretinogram (ERG) was recorded 4 h and 2 weeks after injection. At the end of the ERG follow-up period, retinas were prepared for light microscopy. RESULTS: The ERG b-wave was reduced and the a-wave augmented by both isomers of EAAs when tested 4 h after injection. Long-term (2-week) follow-up indicated severe damage to the retina by both isomers of EAAs. Antagonists to glutamate-gated ionic channels failed to protect the rabbit distal retina from permanent damage. Competitive inhibitors of GLAST-1 transporter were highly effective in blocking synaptic transmission in the OPL and in inducing permanent ERG deficit. Selective inhibition of the GLT-1 transporter caused short-term augmentation of the ERG and no permanent ERG deficit. CONCLUSION: GLAST-1, the glutamate transporter of Müller cells, plays a major role in synaptic transmission within the OPL of the rabbit retina. Over-activation of GLAST-1 seems to induce permanent damage to the distal rabbit retina via yet unidentified mechanism.

Posterior lamellar keratoplasty--comparison of deep lamellar endothelial keratoplasty and Descemet stripping automated endothelial keratoplasty in the same patients: a patient's perspective.

AIM: To evaluate patients' perspectives on endothelial keratoplasty and to compare the outcomes of deep lamellar endothelial keratoplasty (DLEK) and Descemet stripping automated endothelial keratoplasty (DSAEK), performed in the same patients. METHODS: A fellow eye, comparative retrospective case series. The records of 14 patients (28 eyes) who underwent DLEK in one eye and DSAEK surgery in their fellow eye between 2003 and 2007 were reviewed. Two patients were excluded from the study. Both these techniques were compared for intra- and postoperative complications, visual and refractive outcomes including higher-order ocular aberrations (HOA). Patient satisfaction for both procedures was prospectively evaluated using a subjective questionnaire. RESULTS: Nine (75%) of the 12 patients perceived better vision in the DSAEK operated eye. Eight (66.6%) of the patients reported faster recovery following DSAEK. Ten (83%) of them preferred the outcomes of the DSAEK surgery. The intra- and postoperative complications were comparable between both procedures. There was no significant difference in visual outcomes between the procedures. However, the DLEK procedure was associated with a significantly higher degree (p<0.05) of HOA. Endothelial cell loss was similar following DLEK and DSAEK. CONCLUSIONS: We conclude that most patients prefer the DSAEK operation, although there are no differences in visual outcomes between DLEK and DSAEK. Avoidance of surgery-induced hyperopia and HOA is the main benefit of the DSAEK technique.

Femtosecond laser versus manual dissection for top hat penetrating keratoplasty.

AIM: To compare the outcomes of IntraLase-enabled top hat penetrating keratoplasty (IEK) versus retrospective results of manual top hat penetrating keratoplasty (TH-PKP) and conventional PKP. PATIENTS/METHODS: This non-randomised prospective study included 94 eyes: 23 eyes underwent IEK, 36 TH-PKP and 35 conventional PKP. Preoperative and postoperative manifest refraction, uncorrected and best-spectacle corrected visual acuity (BSCVA), high-order ocular aberrations (HOA), endothelial cell counts and complications were analysed. RESULTS: At 12 months of follow-up, the mean log MAR BSCVA was 0.32 (SD 0.31) in the IEK group, 0.53 (0.36) in the TH PKP group (p = 0.03) and 0.39 (0.30) in the conventional PKP group (p = 0.4). The mean spherical equivalent was similar between the groups and was less than -2.2 dioptres. The mean cylinder was similar in the IEK and conventional PKP group (3.6 (1.9) dioptres and 4.1 (1.8) dioptres, respectively), and was significantly lower than the TH-PKP group (5.1 (3.2) dioptres, p = 0.04). The complications rate and high-order ocular aberrations were similar between the three groups studied. The mean endothelial cell loss was significantly lower at 12 months of follow-up in the IEK and the TH-PKP groups versus conventional PKP (32.4% and 22.3% vs 40.8%, respectively) (p = 0.05). The mean time to suture removal was 4.1 (1.2) months in the IEK group and 3.9 (1.5) months in the TH-PKP group versus 9.7 (1.1) months in the conventional PKP group (p<0.0001). CONCLUSIONS: IEK is a safe and stable procedure. It results in higher endothelial counts and faster suture removal in comparison with the conventional PKP, and has less astigmatism and better BSCVA in comparison with the manual TH-PKP.

Scintigraphic evaluation of patients with thyroid carcinoma--therapeutic approaches.

The therapeutic approach to patients with differentiated thyroid carcinoma has become a major issue of controversy in the last decade. The major aspects are the surgical resection and adjuvant therapy, particularly the need for thyroid ablation following surgery. According to the risk group definition suggested by Cady in 1979, low risk patients may be subjected to lobectomy only, then placed on thyroxine treatment and followed clinically with thyroglobulin determination. High risk patients should undergo total thyroidectomy and 131I ablation. Follow-up should include thyroxine treatment and an annual whole body 131I scan. In the event of residual thyroid tissue or functional metastases, 131I treatment is to be given.