Comparison of transcanalicular diode laser dacryocystorhinostomy and external dacryocystorhinostomy in patients with primary acquired nasolacrimal duct obstruction.

BACKGROUND AND OBJECTIVE: To compare the success, complication, and patient discomfort rates of transcanalicular diode laser dacryocystorhinostomy (TCDL-DCR) and external dacryocystorhinostomy (EX-DCR) surgeries performed in patients with primary acquired nasolacrimal duct obstruction. MATERIALS AND METHODS: Eighty consecutive patients were included in the study, and groups were assigned according to DCR technique. Thirty-four (42.5%) patients received TCDL-DCR (Group A) and 46 (57.5%) patients (Group B) received EX-DCR with temporary silicone stent intubation. The success of surgery was determined by the relief of epiphora, patient satisfaction, endoscopic evaluation of ostium patency, and lacrimal system syringing. Pearson Chi-Square test, Fisher's Exact test, and Student's t-test were used for statistical analyses. RESULTS: Group A included 22 females and 12 males with a mean age of 49.1 ± 15.1 years, Group B included 35 females and 11 males with a mean age of 50.8 ± 11.7 years. There was no difference between groups in terms of age and gender (P = 0.905 and P = 0.167, respectively). The duration of the operation was 22.2 ± 4.8 minutes for Group A, while it was 56.3 ± 15.7 minutes for group B (P = 0.0001). In two patients in Group A, injury in the medial turbinate was recorded, and in Group B, 14 patients experienced mild to severe perioperative bleeding. The perioperative complication rate was significantly different between the groups (P = 0.004). Success in relieving symptoms was 79.4% for Group A and 89.1% for Group B. The difference in the success rates was not statistically significant (P = 0.229). CONCLUSIONS: Although EX-DCR success rate was higher than that achieved with TCDL-DCR, the latter, with its shorter duration of surgery, lower perioperative complication rate, and a similar success rate, may be a good and acceptable surgical alternative in treatment of primary acquired nasolacrimal duct obstruction.

Protective effect of hesperetin and naringenin against apoptosis in ischemia/reperfusion-induced retinal injury in rats.

PURPOSE: Hesperetin and naringenin are naturally common flavonoids reported to have antioxidative effects. This study was performed to investigate whether either hesperetin or naringenin has a protective effect against apoptosis on retinal ischemia/reperfusion (I/R) injury. METHODS: Retinal I/R was induced by increasing the intraocular pressure to 150 mmHg for 60 minutes. Thirty-three male Wistar albino rats were randomised into 5 groups named control, I/R + sham, I/R + solvent (DMSO), I/R + hesperetin, and I/R + naringenin. Animals were given either hesperetin, naringenin, or the solvent intraperitoneally immediately following reperfusion. Thickness of retinal layers and retinal cell apoptosis were detected by histological analysis, tunel assay, and immunohistochemistry assay. RESULTS: Hesperetin and naringenin attenuated the I/R-induced apoptosis of retinal cells in the inner and outer nuclear cells of the rat retina. Retinal layer thickness of the naringenin treatment group was significantly thicker than that of the hesperetin, sham, and solvent groups (P < 0.05). CONCLUSIONS: Hesperetin and naringenin can prevent harmful effects induced by I/R injury in the rat retina by inhibiting apoptosis of retinal cells, which suggests that those flavanones have a therapeutic potential for the protection of ocular ischemic diseases.

The protective effects of dexmedetomidine against apoptosis in retinal ischemia/reperfusion injury in rats.

OBJECTIVE: Dexmedetomidine is an alpha 2 adrenoceptor agonist and can be used for postoperative sedation, analgesia and anesthesia-sparing properties. Furthermore, the neuroprotective effects against ischemia/reperfusion (I/R) injury in the central nervous system have been shown in experimental studies. This study aimed to investigate the protective effects of dexmedetomidine against apoptosis in retinal I/R injury in the rat. MATERIALS AND METHODS: Retinal I/R injury was induced by transient elevation of intraocular pressure. Eighteen animals were divided into three groups (n = 6): sham, I/R and treatment. The I/R injury and protective effects of the dexmedetomidine were evaluated by retinal thickness determined by histological sections, terminal deoxynucleotidyl transferase-mediated biotin-deoxyuridine triphosphate nick-end labeling (TUNEL) and immunohistochemistry of caspases 3. RESULTS: A decrease in the retinal thickness and an increase in the apoptotic cells were found to be statistically significant in I/R and treatment groups when compared with the control group. However, in comparison with the I/R group we realized that the administration of dexmedetomidine reduced the thinning of retinal thickness and also decreased the number of caspases 3 and TUNEL-positive cells. CONCLUSION: Dexmedetomidine is protective against apoptosis in retinal I/R injury in rats.

Recurrent dacryocystitis and lacrimocutaneous fistula caused by a retained Griffiths' collar button stent.

A 42-year-old man presented with a white plastic-like material exposed in the left medial canthal area, with a fistula and purulent discharge. He had undergone endonasal dacryocystorhinostomy 7 years earlier for left eye epiphora; he had persistent postoperative epiphora and recurrent dacryocystitis despite multiple drainage attempts and antibiotics elsewhere. Computed tomography showed bilateral enlarged cystic lacrimal sacs, with a well-defined contoured tunnel-like hole at the center of the left sac. Treatment included excision of the foreign body, which was a Griffiths' collar button nasolacrimal stent, excision of the fistula tract, and revision dacryocystorhinostomy with implantation of bicanalicular silicone stent. He recovered with no further symptoms or complications. This case highlights the importance of follow-up for removal of an implanted Griffiths' stent after dacryocystorhinostomy. Patients with recurrent dacryocystitis may benefit from a detailed history of previous surgery, careful examination, and imaging to evaluate for endogenous and exogenous foreign bodies such as lacrimal sac calculi, and retained lacrimal sac stents.

Latanoprost-induced changes in the iris and trabeculum: an electron-microscopic morphological study.

PURPOSE: The purpose was to analyze the histological aspects of irises and trabeculums by transmission electron microscopy (TEM) in patients who had or had not received latanoprost therapy. MATERIALS AND METHODS: Seven patients with pseudoexfoliation glaucoma were enrolled in the study. Four of them had been using latanoprost monotheraphy for 2 months. Iris samples were obtained by peripheral iridectomy. Trabeculum samples were obtained during the trabeculectomy without use of antimetabolites. The specimens were further processed for transmission electron microscopy. RESULTS: There was extracellular pigmentation in the iris stroma in four patients treated with latanoprost, whereas in the control group there was no free melanin in the stroma. Intracellular pigment in fibroblasts, melanocytes, or both was present in all samples in the study group. More pigment accumulation was found in the trabecular endothelial cells of the patients who had received latanoprost therapy. CONCLUSION: Latanoprost therapy causes pigment accumulation in the iris and trabeculum of patients in short-term therapy.

Efficacy of Sunitinib, Sunitinib-Hesperetin, and Sunitinib-Doxycycline Combinations on Experimentally-Induced Corneal Neovascularization.

Purpose: To investigate the preventive effects of topical sunitinib, sunitinib-hesperetin and sunitinib-doxycycline combinations on corneal neovascularization (CNV), apoptosis and fibrosis in a corneal alkali burn model. Materials and Methods: The corneas of 32 Wistar albino rats were cauterized with silver nitrate to induce CNV. Four groups were created receiving artificial tears (sham), sunitinib (0.5 mg/ml), sunitinib-hesperetin (0.5 mg/ml-0.2 mg/ml), and sunitinib-doxycycline (0.5 mg/ml-20 mg/ml) treatments. Corneal photographs were taken on days 0, 7 and 15 . Photographs of the cornea were digitally analyzed to measure the size of the neovascularization area in comparison to the total corneal surface area. On the 15th day, the animals were euthanized, and the eyes were enucleated for immunohistochemical staining to investigate neovascularization, apoptosis, and fibrosis. Results: CNV areas on the 7th day in the sunitinib (4.8% ± 0.07%) and sunitinib-hesperetin (1.1% ± 0.03%) groups were smaller than those in the sham group (33.9% ± 0.12%) (p = 0.001 and, p < 0.001 respectively). On the 15th day, the CNV area in the sunitinib-hesperetin (20.8% ± 0.37%) group was significantly smaller than that of the sham group (74.6% ± 0.32%) (p = 0.039). The combination groups had lower levels of VEGF, TUNEL and α-SMA positivity than the sunitinib monotherapy group. TUNEL positivity was lowest in the sunitinib-hesperetin and sunitinib-doxycycline groups, and α-SMA positivity was lowest in the sunitinib-hesperetin group. Conclusion: Topical sunitinib-hesperetin was more effective than sunitinib alone and the sunitinib-doxycycline combination in the treatment of CNV. The combination of sunitinib and hesperetin seems to be a promising treatment for preventing corneal fibrosis and apoptosis.

The relationship between plasma MMP-9 and TIMP-2 levels and intraocular pressure elevation in diabetic patients after intravitreal triamcinolone injection.

PURPOSE: To find out the relationship between steroid-induced intraocular pressure (IOP) rise and the plasma levels of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of MMP-2 (TIMP-2) in diabetic patients who underwent intravitreal triamcinolone acetonide (IVTA) injection for the treatment of diabetic macular edema. SUBJECTS AND METHODS: A total of 34 patients with diabetic macular edema who were treated with IVTA and 17 healthy subjects who served as control group for plasma MMP and TIMP levels were participated. Before IVTA treatment, patients and control subjects underwent complete ophthalmologic examination, including best-corrected visual acuity, slit-lamp biomicroscopy, IOP measurement with Goldmann applanation tonometry, and indirect ophthalmoscopy; and peripheral blood samples were collected from each study participants. Plasma levels of MMP-9, TIMP-2, and HbA1c levels were measured. Patients were seen 1, 6, 12, and 24 weeks after treatment and then every 6 months for up to 1 year for probable IOP rise. Patients were divided into 2 groups as having nonproliferative or proliferative diabetic retinopathy. These 2 groups were further classified according to their IOP levels as normal or elevated IOP (>21 mm Hg). RESULTS: The mean age of diabetic group of patients (n=34) and healthy control subjects (n=17) were 57.6+/-10.2 years (range: 22 to 70 y) and 53.1+/-10.3 years (range: 29 to 68 y), respectively. Seventeen (50%) diabetic patients had developed elevated IOP after a mean 2.2 months after IVTA injection. MMP-9 and TIMP-2 levels were found to be significantly higher in the diabetic groups with and without elevated IOP when compared with control group (P<0.001). MMP-9/TIMP-2 did not change significantly among the groups. Logistic regression analysis showed that only higher plasma TIMP-2 levels increase the risk of IOP elevation after IVTA injection in proliferative diabetic retinopathy (odds ratio=1.06, P<0.05). No significant relationship was found between IOP rise and HbA1c levels. CONCLUSIONS: The high levels of TIMP in diabetic patients might have a role on steroid-induced IOP rise. The key pathogenetic events that up-regulate TIMP levels should be investigated in steroid IOP rise in diabetics.

The Effect of Smoking on Corneal Endothelial Cells.

PURPOSE: To investigate the effect of chronic cigarette smoking on the endothelial cells of the cornea via non-contact specular microscopy. METHOD: In this prospective, cross-sectional study, 25 eyes of 25 chronic smokers and 21 eyes of 21 age-matched, healthy non-smokers were enrolled. The Fagerström Test for Nicotine Dependence on Cigarettes was used to determine the nicotine dependency level. The level of cotinine, a major metabolite of nicotine, was measured in urine samples from the control group to detect whether they were passively affected by cigarette smoke. All participants underwent measurement of tear break-up time (TBUT), central corneal thickness (CCT), and axial length. Endothelial cell density and endothelial cell morphology were evaluated by non-contact specular microscopy. RESULTS: On average, the cigarette smokers consumed 19.2 ± 8.3 cigarettes per day and had been smoking for 14.5 ± 6.8 years. The mean TBUT value was significantly lower in the smoker group compared to the non-smoker group (p < 0.05). No statistically significant difference was found in the mean CCT, mean endothelial cell density, or parameters of endothelial cell morphology between smokers and non-smokers. CONCLUSION: This study showed that cigarette smoking seems to affect the TBUT value but no effects were found on the parameters of corneal endothelial cells.

Evaluation of Macular Ganglion Cell-inner Plexiform Layer and Choroid in Psoriasis Patients Using Enhanced Depth Imaging Spectral Domain Optical Coherence Tomography.

PURPOSE: To evaluate changes in the thickness of the central macula, macular ganglion cell-inner plexiform layer (mGCIPL), and subfoveal choroid in patients with psoriasis using spectral domain optical coherence tomography (SD-OCT). METHODS: The measurements of macular, mGCIPL thicknesses and subfoveal choroidal thickness (SFCT) obtained by SD-OCT of psoriasis patients (n = 46). These measurements were compared with those of 50 healthy controls. RESULTS: The macular, mGCIPL, and choroidal thicknesses did not differ between the controls and psoriatic subjects (p>0.05). When the patients were divided into two distinct groups, only the SFCT was significantly thicker in the severe psoriasis group compared with the mild psoriasis group (p = 0.003). CONCLUSIONS: These findings suggest that choroidal alterations are seen without macular changes in patients with psoriasis. Severe psoriasis appears to be related to increases in SFCT as a consequence of possible inflammatory cascades that are part of the disease's pathogenesis.

Effect of Reduced Meal Frequency during Ramadan Fasting on Retinal and Choroidal Thickness.

PURPOSE: To evaluate the effects of Ramadan fasting on central foveal thickness (CFT) and subfoveal choroidal thickness (SFCT) in healthy individuals using enhanced depth imaging optical coherence tomography (EDI-OCT). MATERIALS AND METHODS: The EDI-OCT scans of 42 healthy individuals obtained after about 12 hours of fasting on at least the twenty-first consecutive day of fasting were compared to scans of the same patients taken one month after the last day they had fasted. RESULTS: CFT values were similar for both time periods (p > 0.05). The SFCT was significantly higher after consecutive fasting days towards the end of Ramadan, compared to the SFCT after one month of no fasting (one month after Ramadan ended) (p < 0.001). CONCLUSIONS: Ramadan fasting may lead to a significant increase in subfoveal choroidal thickness without affecting the central foveal thickness.

Effect of Systemically Used Anti-Tumor Necrosis Factor-α Medication on the Corneal Epithelium and Stroma of Patients with Ankylosing Spondylitis.

PURPOSE: To evaluate the effect of systemically used anti-tumor necrosis factor alpha (TNF-α) medication on the thickness of corneal epithelium and stroma in patients with ankylosing spondylitis (AS). METHODS: A total of 125 eyes of 69 participants were included in this retrospective study of three groups: healthy participants (Group 1), AS patients receiving anti-TNF-α medication (Group 2), and AS patients receiving a nonsteroidal anti-inflammatory medication (Group 3). RESULTS: According to anterior segment optical coherence tomography, the mean thickness of the corneal epithelium was significantly thicker in Group 2 than in Group 3 (51.6 ± 3.2 µm versus 50.4 ± 3 µm, p = 0.01), as was that of the stroma (475 ± 33 µm versus 443 ± 29 µm, p = 0.002). CONCLUSIONS: Anti-TNF-α medication and/or avoidance of nonsteroidal anti-inflammatory drugs could improve the thickness of both the corneal epithelium and stroma in AS patients.

Does Retinal Neurodegeneration Seen in Diabetic Patients Begin in the Insulin Resistance Stage?

OBJECTIVES: To investigate whether retinal neurodegeneration and impairment in contrast sensitivity (CS), which have been demonstrated to begin in diabetic patients before the presence of signs of diabetic retinal vasculopathy, also occur in the stage of insulin resistance. MATERIALS AND METHODS: The average, minimum and sectoral (inferior, superior, inferonasal, superonasal, inferotemporal and superotemporal) thicknesses of the ganglion cell-inner plexiform layer (GCIPL) measured using optical coherence tomography were compared between an insulin-resistant group and control group in order to evaluate the presence of retinal neurodegeneration. The CS of the two groups was also compared according to the logarithmic values measured at spatial frequencies of 1.5, 3, 6, 12 and 18 cycles per degree in photopic light using functional acuity contrast test (FACT). RESULTS: Twenty-five eyes of 25 patients with insulin resistance (insulin resistant group) and 25 eyes of 25 healthy subjects (control group) were included in this study. There were no statistically significant differences between the two groups in any of the spatial frequencies in the FACT. The mean average GCIPL thickness and mean GCIPL thickness in the inferotemporal sector were significantly less in the insulin-resistant group when compared with the control group (mean average GCIPL thicknesses in the insulin-resistant and control groups were 83.6±4.7 µm and 86.7±3.7 µm respectively, p=0.01; mean inferotemporal GCIPL thicknesses in the insulin-resistant and control groups were 83±6.0 µm and 86.7±4.6 µm respectively, p=0.02). CONCLUSION: Although it may not lead to functional visual impairment such as CS loss, the retinal neurodegeneration seen in diabetic patients may begin in the insulin resistance stage.

Non-invasive assessment of corneal and conjunctival deterioration in soft contact lens users using anterior segment optical coherence tomography.

BACKGROUND: The aim was to evaluate the corneal and bulbar conjunctival thicknesses of soft contact lens (SCL) wearers using anterior segment optical coherence tomography (AS-OCT). METHODS: The epithelial and overall thicknesses of both the central cornea and the infero-temporal bulbar conjunctiva of SCL wearers (30 subjects) were obtained by Cirrus HD-OCT and compared with those of refraction-matched controls (30 subjects) and patients with emmetropia (30 subjects). RESULTS: The mean corneal epithelial thicknesses in SCL wearing, spectacle-wearing and emmetropic groups were 48.97 ± 5.45, 52.18 ± 4.84 and 53.18 ± 5.05 µm, respectively. The corneal epithelium of members of the SCL group was significantly thinner than in both the spectacles and emmetropic groups (p = 0.044 and 0.006, respectively), whereas the central corneal thickness did not differ between groups (p = 0.210). The mean conjunctival epithelial thicknesses in SCL, spectacles and emmetropic groups were 41.50 ± 7.75, 54.33 ± 8.39 and 49.10 ± 7.11 µm, respectively. Conjunctival epithelium in the SCL group was significantly thinner than in both spectacle-wearing and emmetropic groups (p < 0.001 and p = 0.001, respectively). The conjunctiva was significantly thinner in the SCL group compared to the spectacles group (p = 0.001) but not the emmetropic group. CONCLUSIONS: Contact lens wear is related to thinning of both corneal and conjunctival layers. AS-OCT is a non-invasive and clinically applicable technique for assessing the involvement of the cornea and conjunctiva in contact lens wearers.

Noninvasive assessment of the retina and the choroid using enhanced-depth imaging optical coherence tomography shows microvascular impairments in childhood obesity.

PURPOSE: To evaluate the retinal vascular diameters and macular and subfoveal choroidal thicknesses of obese and nonobese children using enhanced-depth imaging spectral domain optical coherence tomography (EDI SD-OCT). METHODS: The retinal vascular diameters of the 4 largest retinal arterioles and venules and macular and subfoveal choroidal thickness measurements of 40 obese children (body mass index [BMI] z score above +2.0 standard deviations) were obtained by EDI SD-OCT and compared with those of 40 age- and sex-matched nonobese children. Anthropometric measures, including weight and height, were also obtained. BMI z score was defined using standardized protocols. RESULTS: The mean BMI z scores of obese children were 2.59 ± 0.62; of nonobese children, -0.20 ± 0.92. The mean diameter of retinal arterioles was significantly smaller (P = 0.002) in obese children compared to nonobese children, whereas the mean diameter of retinal venules was larger (P = 0.008). The macular and subfoveal choroidal thicknesses were significantly thinner (P = 0.031 and 0.014, resp.) in obese children compared to nonobese children. CONCLUSIONS: The narrower retinal arterioles, wider retinal venules, and thinner macular and subfoveal choroidal thicknesses in obese children seem to be associated with microvascular impairments in childhood obesity.

Repeatability of contrast sensitivity testing in patients with age-related macular degeneration, glaucoma, and cataract.

PURPOSE:: To analyze the intrasession and intersession repeatability of contrast sensitivity (CS) measurements in patients with glaucoma, cataract, or age-related macular degeneration (AMD) and healthy controls. METHODS:: CS measurements were performed using the OPTEC-Functional Vision Analyzer (FVA), which uses a standardized and closed (view-in) system. Measurements for patients with glaucoma, cataract, or AMD and healthy controls were repeated within 30 minutes (intrasession) and during two sessions (intersession), separated by one week to one month. Test-retest reliability and correlation were measured using the intraclass correlation coefficient (ICC) and coefficient of repeatability (COR). RESULTS:: Ninety subjects (90 eyes) with visual acuity of 0.17 logMAR or higher in the cataract group or 0.00 logMAR in the other groups were included. During the first session, the ICC values were 0.87, 0.90, 0.76, and 0.69, and COR values were 0.24, 0.20, 0.38, and 0.25 for the control, glaucoma, cataract, and AMD groups, respectively. The reliability scores significantly improved during the second session, except in the glaucoma group. There was an acceptable floor effect and no ceiling effect at higher frequencies in the glaucoma and AMD groups. CONCLUSION:: In subjects with good visual acuity, the FVA system is useful for evaluating CS and demonstrates good repeatability, as shown by ICC and COR. Because there is no ceiling effect, this system is beneficial for evaluation of early changes in CS, particularly in patients with glaucoma or AMD.

Corneal thickness of eyes with unilateral age-related macular degeneration.

PURPOSE: To compare the central corneal thicknesses (CCT), peripheral corneal thicknesses, and corneal volumes (CV) of the 2 eyes of patients with unilateral age-related macular degeneration (AMD). METHODS: Twenty patients who were diagnosed with unilateral AMD were included in this prospective study for the purpose of making comparison between the diseased and healthy eyes. Optical coherence tomography and fundus fluorescein angiography imaging were applied to all patients in order to confirm and reveal the presence of unilateral AMD. Then, the measurements of CCT, peripheral corneal thickness measured 4 mm distant from the center of the cornea (4 mm CT), and CV of each eye of these patients were obtained through the rotating Scheimpflug corneal topographer. RESULTS: Wilcoxon signed-rank test did not demonstrate a statistically significant difference between the 2 eyes of patients with unilateral AMD when we compared the CCT and CV of diseased and healthy eyes (p>0.05). However, 4 mm CT of the diseased eyes of these patients were statistically significantly thicker than the healthy eyes (p<0.05). CONCLUSIONS: The significant difference in terms of 4 mm CT between the diseased and healthy eyes of patients with unilateral AMD may demonstrate the possible effect of peripheral corneal thickness on the development of AMD.

Evaluation of possible factors affecting contrast sensitivity function in patients with primary Sjögren's syndrome.

PURPOSE: The contrast sensitivity (CS) function in patients with primary Sjögren's syndrome (pSS) may be impaired either frequently as a result of dry eye diseases or rarely as a result of optic neuropathy. In this study, we aimed to evaluate the CS function in pSS patients as well as to assess corneal aberrations and thickness of the peripapillary retinal nerve fiber layer (pRNFL). METHODS: Fourteen eyes of 14 pSS patients (pSS group) and 14 eyes of 14 healthy participants (control group) were subjected to assessment of CS at the spatial frequencies of 1.5, 3.0, 6.0, 12, and 18 cycles/degree (cpd) using a functional visual acuity contrast test (FACT); measurement of corneal high-order aberrations (HOAs) in terms of coma-like, spherical-like, and total HOAs using Scheimpflug corneal topography; and measurement of the thickness of both the macular ganglion cell-inner plexiform layer (mGCIPL) and pRNFL in all quadrants using optical coherence tomography. None of the participants were under treatment with artificial tears. RESULTS: The results of the CS test did not differ between the 2 groups at all spatial frequencies (p>0.05). In addition, there were no statistically significant differences between the 2 groups in terms of corneal HOAs (p>0.05) and thickness of mGCIPL (p>0.05). However, among all quadrants, only the inferior quadrant of pRNFL in pSS patients was statistically significantly thinner than that in the healthy participants (p=0.04). CONCLUSIONS: The CS function in pSS patients can be maintained with normal thickness of both pRNFL and mGCIPL and with lack of increased corneal HOAs, which may be present even in the absence of artificial tear usage.

Quercetin protects the retina by reducing apoptosis due to ischemia-reperfusion injury in a rat model.

PURPOSE: This study aimed to investigate the effect of quercetin on apoptotic cell death induced by ischemia-reperfusion (I/R) injury in the rat retina. METHODS: Twenty-four rats were divided into four equal groups: control, ischemic, solvent, and quercetin. I/R injury was achieved by elevating the intraocular pressure above the perfusion pressure. Intraperitoneal injections of 20 mg/kg of quercetin and dimethyl sulfoxide (DMSO) were performed in the quercetin and solvent groups, respectively, immediately prior to I/R injury, and the researchers allowed for the retinas to be reperfused. Forty-eight hours after injury, the thicknesses of the retinal ganglion cell layer (RGCL), inner nuclear layer (INL), inner plexiform layer (IPL), outer plexiform layer (OPL), and outer nuclear layer (ONL) were measured in all groups. Moreover, the numbers of terminal deoxynucleotidyl transferase dUTP nick-end-labeled [TUNEL (+)] cells and caspase-3 (+) cells in both INL and ONL were evaluated in all groups. RESULTS: The administration of quercetin was found to reduce the thinning of all retinal layers. The mean thickness of INL in the quercetin and ischemic groups was 21 ± 5.6 µm and 16 ± 6.4 µm, respectively (P<0.05). Similarly, the mean thickness of ONL in the quercetin and ischemic groups was 50 ± 12.8 µm and 40 ± 8.7 µm, respectively (P<0.05). The antiapoptotic effect of quercetin in terms of reducing the numbers of both TUNEL (+) cells and caspase-3 (+) cells was significant in INL. The mean number of TUNEL (+) cells in INL in the ischemic and quercetin groups was 476.8 ± 45.6/mm2 and 238.72 ± 251/mm2, respectively (P<0.005). The mean number of caspase-3 (+) cells in INL of ischemic and quercetin groups was 633.6 ± 38.7/mm2 and 342.4 ± 36.1/mm2, respectively (P<0.001). CONCLUSION: The use of quercetin may be beneficial in the treatment of retinal I/R injury because of its antiapoptotic effect on the retinal layers, particularly in INL.

Blood gas analyzer utility in evaluating oxygen kinetics of the aqueous humor.

PURPOSE: To measure the partial pressure of oxygen (PO2) and carbon dioxide (PCO2) and the pH of aqueous humor (AH) and arterial blood samples from rabbits using a blood gas analyzer. METHODS: Twenty New Zealand rabbits were anesthetized intramuscularly with ketamine and xylazine and were then allowed to breathe room air. Using a gas blood analyzer, arterial blood and AH samples were analyzed for PO2, PCO2, and pH. RESULTS: The mean arterial blood pressure was 87.14 ± 15.0 mmHg. The mean blood and AH PO2 were 95.18 ± 11.76 mmHg and 88.83 ± 9.92 mmHg, the mean blood and AH PCO2 were 25.86 ± 5.46 mmHg and 29.50 ± 5.36 mmHg, and the mean blood and AH pH were 7.38 ± 0.06 and 7.33 ± 0.09, respectively. CONCLUSIONS: The blood gas analyzer was easily employed to evaluate the aqueous humor in rabbits. When comparing the results of studies evaluating aqueous PO2, care should be taken to determine the methods used in these studies.

[Changes in retinal nerve fiber layer thickness after spinal surgery in the prone position: a prospective study]. / Alterações da espessura da camada de fibras nervosas da retina após cirurgia da coluna vertebral em pronação: estudo prospectivo.

BACKGROUND AND OBJECTIVES: Changes in ocular perfusion play an important role in the pathogenesis of ischemic optic neuropathy. Ocular perfusion pressure is equal to mean arterial pressure minus intraocular pressure. The aim of this study was to evaluate the changes in the intraocular pressure and the retinal nerve fiber layer thickness in patients undergoing spinal surgery in the prone position. METHODS: This prospective study included 30 patients undergoing spinal surgery. Retinal nerve fiber layer thickness were measured one day before and after the surgery by using optical coherence tomography. Intraocular pressure was measured by tonopen six times at different position and time-duration: supine position (baseline); 10min after intubation (Supine 1); 10 (Prone 1), 60 (Prone 2), 120 (Prone 3)min after prone position; and just after postoperative supine position (Supine 2). RESULTS: Our study involved 10 male and 20 female patients with the median age of 57 years. When postoperative retinal nerve fiber layer thickness measurements were compared with preoperative values, a statistically significant thinning was observed in inferior and nasal quadrants (p=0.009 and p=0.003, respectively). We observed a statistically significant intraocular pressure decrease in Supine 1 and an increase in both Prone 2 and Prone 3 when compared to the baseline. Mean arterial pressure and ocular perfusion pressure were found to be significantly lower in Prone 1, Prone 2 and Prone 3, when compared with the baseline. CONCLUSIONS: Our study has shown increase in intraocular pressure during spinal surgery in prone position. A statistically significant retinal nerve fiber layer thickness thinning was seen in inferior and nasal quadrants one day after the spinal surgery.