The Impact of COVID-19 Infection on Macular Capillary Perfusion.

Objectives: Thromboembolic complications related to the COVID-19 infection are frequently reported. This study aims to evaluate the impact of a prior non-severe COVID-19 infection on retinal microcirculation with optical coherence tomography angiography (OCTA). Methods: A total of 83 eyes of 43 patients with a history of non-severe COVID-19 infection confirmed with a positive PCR test (Group 1) and 30 healthy controls (Group 2) underwent detailed eye examination, including optic coherence tomography angiography (OCTA, RTVue-XR Avanti) scanning. Vessel densities (VD) in the superficial capillary plexus (SCP), deep capillary plexus (DCP), and foveal avascular zone were evaluated. Results: The mean duration between the COVID-19 positive PCR test and ocular examination was 144.6±82.2 days. VD of SCP and DCP in the foveal and perifoveal regions were significantly lower in Group 1 compared to Group 2 (p<0.05). Conclusion: A non-severe COVID-19 infection may cause a decrease in the VD of retinal SCP and DCP.

Radiation-Induced Ocular Surface Disorders and Retinopathy: Ocular Structures and Radiation Dose-Volume Effect.

PURPOSE: This study aimed to evaluate the radiation-induced adverse effects on ocular structures in head and neck cancer patients and investigate the radiation dose-volume effects on the cornea, lacrimal gland, retina, optic nerve and chiasm. MATERIALS AND METHODS: A total of 38 eyes of 19 patients were included in this prospective, cohort study. All patients underwent complete ophthalmological examination in addition to contrast sensitivity, visual field and visual evoked potentials (VEP) tests. Ophthalmological examinations and psychophysical tests were performed in 6th, 12th, 18th, 24th months and in the last visit. The relationship between the ophthalmologic findings, and the radiation doses below and above the cut-off values was evaluated. RESULTS: Contrast sensitivity decrease and visual field deterioration were observed in 42% of the patients in the last visit (median 26 months) whereas a prolonged latency and decreased amplitude of P100 wave in VEP was observed in 58% and 33% of the eyes, respectively at 24th month. Totally 16 patients (84.2%) developed dry eye disease and eight of them received radiotherapy below tolerance doses and had mild to moderate dry eye findings. Radiation-induced retinopathy was observed in three of the eyes in eight patients who received radiation above tolerance dose. CONCLUSION: Head and neck cancers treated with radiotherapy, resulted in various ophthalmic complications. All patients who are treating with radiotherapy should be evaluated by an ophthalmologist in terms of anterior and posterior segment damage, even if the radiation dose is below the tolerance limit.

Rheumatologic manifestations in a cohort of patients with Vogt-Koyanagi-Harada disease.

OBJECTIVES: Vogt-Koyanagi-Harada Disease (VKHD) is a systemic autoimmune disorder characterized by granulomatous panuveitis. Inflammatory rheumatic diseases (IRDs) are among the differential diagnosis of VKHD. However, current knowledge on the rheumatological aspects of VKHD is still limited. We aimed to investigate the prevalence of rheumatic conditions in VKHD patients. METHODS: VKHD patients were included in the study and they were reviewed in terms of the presence of any rheumatological manifestations. RESULTS: There were 18 patients with a female preponderance (83.3%, female). Inflammatory type of peripheral joint pain (11%) and sicca symptoms (33%) were the most common rheumatological findings. The frequency of spondyloarthritis-related features such as inflammatory back pain and HLA-B27 rate was not increased. None of the patients had radiographic sacroiliitis. Anti-nuclear antibody was positive in high titres nearly in 30% of the patients and three patients had antibodies against extractable nuclear antigens. Nailfold capillaroscopy was abnormal in about one-third of the patients. Pathergy test was negative in all cohorts. While angiotensin-converting enzyme was elevated in nearly 20% of the patients, there were no abnormalities on chest X-rays. CONCLUSION: VKHD shares some features with IRDs. The common features were mostly suggestive of connective tissue disease rather than SpA or rheumatoid arthritis.

Multimodal Imaging Characteristics of Circumscribed Choroidal Hemangioma Accompanying with Central Serous Chorioretinopathy: A Case Report.

A 42-year-old man presented with a temporal visual field defect in his right eye. His history revealed systemic steroid use before onset of his complaints. Multimodal imaging techniques including ultrasonography, fluorescein angiography, indocyanine green angiography, and optical coherence tomography angiography (OCTA) suggested the presence of circumscribed choroidal hemangioma (CCH) accompanying with central serous chorioretinopathy (CSCR) in the right eye, which might have worsened with systemic steroid treatment. CCH may rarely present with accompanying CSCR. Besides, OCTA is a non-invasive reliable method for the diagnosis of CCH in terms of visualizing vascular features of tumor.

Retinal Nerve Fiber Layer Thickness Correlates with Serum and Cerebrospinal Fluid Neurofilament Levels and is Associated with Current Disability in Multiple Sclerosis.

INTRODUCTION: The main purpose of the present study is to confirm Peripapillary Retinal Nerve Fiber Layer (pRNFL) thickness is a biomarker of axonal degeneration in patients with Multiple Sclerosis (MS) and to evaluate its relationship with Neurofilament heavy chain (NfH) and Nitrotyrosine (NT). METHOD: We quantified serum (s) and/or cerebrospinal fluid (CSF) NfH and NT levels in 30 relapsing-remitting MS patients (RRMS), 16 secondary progressive MS (SPMS) patients and in 29 control subjects matched for age and gender. Optical coherence tomography (OCT) measurements of pRNFL were performed in all subjects. Clinical outcomes were tested by Multiple Sclerosis Functional Composite (MSFC) and Expanded Disability Status Scale (EDSS). RESULTS: RRMS patients exhibited significantly higher NfH/NT levels (99 pg/mL, 107.52 nM respectively) than controls (74 pg/mL, 48.72 nM) in CSF (p<0.0001), but not in sera. SPMS patients had significantly higher s NfH/NT values (111.25 pg/mL, 1251.77 nM respectively) and lower mean pRNFL thickness (79 µm) than patients with RRMS (98.50 µm) and controls (108 µm) (p<0.0001). pRNFL thickness was significantly correlated with all clinical disability measurements (EDSS, Trail Making test, 9-Hole Peg Test, and PASAT) in both RRMS and SPMS (p<0.001, p=0.02, p=0.03, p=0.02 respectively). A positive correlation was also found between serum and/or CSF NfH levels and EDSS scores in RRMS and SPMS (p<0.001, p=0.02 respectively). The pRNFL thickness was also correlated significantly with serum and/or CSF NfH levels but not with s/CSF NT levels in both clinical forms of MS (p<0.01, p<0.001 respectively). CONCLUSION: The current study demonstrated that both pRNFL and s/CSF NfH are reliable and quantitative biomarkers that correlate with current disease course and cross-sectional measure of disability in patients with MS.

Assessment of macular capillary perfusion in patients with inactive Vogt-Koyanagi-Harada disease: an optical coherence tomography angiography study.

PURPOSE: To assess macular capillary perfusion in patients with inactive Vogt-Koyanagi-Harada (VKH) disease by using optical coherence tomography angiography (OCTA). METHODS: A total of 51 eyes of 51 patients with inactive VKH (group 1, n = 23) and healthy volunteers (group 2, n = 28) underwent detailed eye examination including OCTA (RTVue-XR Avanti) scanning. OCTA images (6 × 6 mm) were assessed for central retinal thickness (CRT), subfoveal choroidal thickness (SFCT), vessel densities (VD) in superficial capillary plexus (SCP) and deep capillary plexus (DCP), choriocapillaris (CC) flow area and vessel flow density (VFD), foveal avascular zone (FAZ) area and acircularity index (AI). RESULTS: The mean ages of group 1 (13 female, 10 male) and group 2 (15 female, 13 male) were 39.9 ± 11.8 (range, 24-58) and 38.9 ± 8.5 (range, 29-51) years, respectively (p = 0.773). CRT and SFCT were 218.2 ± 39.4 µm and 195.6 ± 28.6 µm in group 1, while 243.5 ± 9.7 µm and 316.7 ± 20.1 µm in group 2, respectively (p < 0.05). VD in SCP and DCP were significantly lower in group 1 (50.6 ± 4.7% vs. 54.3 ± 3.4% and 53.9 ± 3.6% vs. 61.1 ± 2.7% respectively; p < 0.05). FAZ areas were 0.32 ± 0.11 mm2 in group 1 and 0.25 ± 0.06 mm2 in group 2 (p = 0.046). There was no statistically significant difference between groups regarding AI, CC flow area, and VFD (p > 0.05). There was weak negative correlation between BCVA (logMAR) and parafoveal and perifoveal VD in SCP and DCP of group 1 (p < 0.05). CONCLUSION: Macular capillary perfusion was significantly reduced both in SCP and DCP in patients with inactive VKH disease.

Correlation between corneal involvement and anterior chamber flare in epidemic keratoconjunctivitis.

PURPOSE: To investigate the correlation between corneal involvement and anterior chamber flare using a laser flare meter in eyes with epidemic keratoconjunctivitis. METHODS: A total of 82 eyes of 50 (32 female and 18 male) consecutive patients with epidemic keratoconjuctivitis were evaluated. Besides complete opthalmic examination, anterior chamber flare measurements with laser flare meter (FM 600, Kowa, Kowa Company Ltd., Nagoya, Japan) were performed. The relationship between corneal involvement, subepithelial deposits, and anterior chamber flare was assessed. RESULTS: The mean age of the patients was 36.32 ± 18.77 (range 4-75) years and the mean duration of complaints was 5.28 ± 2.65 (range 1-12) days. The biomicroscopic findings were conjunctival hyperemia in 82 (100%), follicular reaction in 66 (80.5%), eyelid edema in 56 (68.3%), punctate epitheliopathy in 38 (46.3%), and subepithelial deposits in 36 (43.9%) eyes. The mean flare value was 17.35 ± 12.62 (range 2.0-45.0) photons/ms. Flare measurements were significantly higher in eyes with subepithelial deposits (p < 0.001). CONCLUSIONS: Subepithelial deposits seem to occur in eyes with higher anterior chamber inflammation in epidemic keratoconjunctivitis. The laser flare meter might be a useful tool to predict subepithelial deposit development in these patients.

Evaluation of CNTNAP2 gene rs2107856 polymorphism in Turkish population with pseudoexfoliation syndrome.

PURPOSE: To investigate rs2107856 single-nucleotide polymorphism (SNP) of CNTNAP2 gene in Turkish population with pseudoexfoliation and to correlate clinical characteristics with the genotypic profile. MATERIALS AND METHODS: Forty-three patients with pseudoexfoliation syndrome (PXS), 46 patients with pseudoexfoliation glaucoma (PXG) and 99 healthy controls were enrolled. Comprehensive ophthalmological examination, central corneal thickness measurement and retinal nerve fiber layer thickness analysis of the peripapillary area were performed. Blood samples of 2 mL with EDTA were obtained and sent for genetic analysis. The role of the detected polymorphism on disease tendency along with the genotype and allele frequencies in each group was evaluated. RESULTS: The mean age of the groups was 70.0 ± 8.0 (range 51-86) in PXS, 71.2 ± 8.8 (range 51-93) in PXG and 64.6 ± 8.3 (range 51-91) in controls. The percentages of homozygote individuals were 11.6, 10.9, 21.2%, and heterozygote individuals were 41.9, 45.7, 42.4% in patients with PXS, PXG and controls, respectively. There was no statistically significant difference between groups in terms of both genotype and allele frequencies of rs2107856 (p = 0.429 and p = 0.178, respectively). Retinal nerve fiber layer thickness did not differ between SNP-positive and SNP-negative individuals in PXG, and there was no significant difference between genotype and age, sex, best corrected visual acuity, intraocular pressure, central corneal thickness, cup/disk ratio and retinal nerve fiber layer thickness in any of the groups (p > 0.05). CONCLUSION: rs2107856 SNP of CNTNAP2 gene has no association with PXS and PXG in the evaluated Turkish population.

Treatment results in aphakic patients with glaucoma following congenital cataract surgery.

PURPOSE: To evaluate the clinical findings and possible risk factors of patients with aphakic glaucoma following congenital cataract surgery and identify the factors affecting response to glaucoma treatment. METHODS: A retrospective chart review of 173 patients was performed who underwent congenital cataract surgery before the age of 12 months and 40 eyes of 25 patients with aphakic glaucoma were enrolled. Age of the patients at the time of the cataract surgery, postoperative complications, additional ocular pathologies and the type of glaucoma treatment needed were investigated. RESULTS: Mean age of 25 patients at the time of cataract surgery was 3.31 ± 2.28 (range 1-11) months with a mean follow-up period of 79 ± 30.5 (32-176) months. Out of 40 eyes, medical therapy was effective in 20 (50%) eyes, whereas 20 (50%) eyes needed surgery for glaucoma. In these 20 eyes, 6 (30%) eyes underwent only 1, 4 (20%) eyes underwent 2 and 10 (50%) eyes underwent 3 or more procedures. Age at the time of cataract surgery, pupillary membrane formation and additional ocular pathologies were not significantly associated both with the need for glaucoma surgery or the number of operations (p ≥ 0.05). CONCLUSION: Aphakic glaucoma following congenital cataract surgery is a serious complication which requires surgery in half (50%) of the patients. Usually, more than one surgical procedure (70%) is needed. It can be detected even years after cataract surgery (range 0.3-94 months), so long-term careful follow-up is necessary.

Characteristics of optic neuropathy in Behçet disease.

OBJECTIVE: We present the clinical profile, features, and neuroimaging findings of 25 patients with Behçet disease (BD), and optic neuropathy (ON), which has been rarely reported in BD. METHODS: Data from 5 university hospitals were retrospectively reviewed, and patients with BD and ON were evaluated. There were 2 groups: (1) those already diagnosed with BD when ON developed (BD→ON group) and (2) those diagnosed with BD during the evaluation of ON (ON→BD group). RESULTS: There were 25 BD patients with ON (13 males). Among these, 13 had ON→BD, and 12 had BD→ON. Seventeen patients had unilateral ON, and 7 patients had recurrent ON. BD→ON patients were older. Disc edema was seen more in ON→BD than in BD→ON patients (10 vs 3). Fourteen patients also had uveitis, 7 with BD→ON and 7 with ON→BD. There was other neurologic involvement in 8 patients; in the BD→ON group, 4/4 had MS-like disease, in the ON→BD group, 3 had typical parenchymal BD, and 1 had MS-like disease. Twenty of 21 patients received immunosuppressive medications, corticosteroids, or both. Prognosis was favorable in most: vision improved in 20 patients, more often in those receiving combined therapies. CONCLUSION: BD may be diagnosed earlier if it is considered and investigated during the assessment of ON, particularly in high-risk regions. Prognosis of ON related to BD seems to be favorable. Immunosuppressants should be given along with corticosteroids. MS-like presentations should also be kept in mind in patients with BD and ON.

Comparison of central corneal thickness and endothelial cell measurements by Scheimpflug camera system and two noncontact specular microscopes.

PURPOSE: To investigate the correlation of Scheimpflug camera system and two noncontact specular microscopes in terms of central corneal thickness (CCT) and corneal endothelial cell morphology measurements. METHODS: One hundred eyes of 50 healthy subjects were examined by Pentacam Scheimpflug Analyzer, CEM-530 (Nidek Co, Ltd, Gamagori, Japan) and CellChek XL (Konan Medical, California, USA) via fully automated image analysis with no corrections made. Measurement differences and agreement between instruments were determined by intraclass correlation analysis. RESULTS: The mean age of the subjects was 36.74 ± 8.59 (range 22-57). CCTs were well correlated among all devices, with having CEM-530 the thinnest and CellChek XL the thickest measurements (intraclass correlation coefficient (ICC) = 0.83; p < 0.001 and ICC = 0.78; p < 0.001, respectively). Mean endothelial cell density (ECD) given by CEM-530 was lower than CellChek XL (2613.17 ± 228.62 and 2862.72 ± 170.42 cells/mm2, respectively; ICC = 0.43; p < 0.001). Mean value for coefficient of variation (CV) was 28.57 ± 3.61 in CEM-530 and 30.30 ± 3.53 in CellChek XL. Cell hexagonality (HEX) with CEM-530 was higher than with CellChek XL (68.70 ± 4.16% and 45.19 ± 6.58%, respectively). CONCLUSIONS: ECDs with CellChek XL and CEM-530 have good correlation, but the values obtained by CellChek XL are higher than CEM-530. Measurements for HEX and CV differ significantly and show weak correlation. Thus, we do not recommend interchangeable use of CellChek XL and CEM-530. In terms of CCTs, Pentacam, CEM-530 and CellChek XL specular microscopy instruments are reliable devices.

A novel mutation and in vivo confocal microscopic findings in Fabry disease.

Fabry disease is a hereditary, X-linked lysosomal storage disease due to a deficiency of the alpha galactosidase A enzyme. Globotriaosylceramide accumulates in tissues and results in multiorgan dysfunction. The most common ocular finding in Fabry disease is cornea verticillata. Increase in conjunctival vascular tortuosity, and cataract may also be seen. Herein, we demonstrate the in vivo confocal microscopic findings of a genetically proven Fabry disease patient with a novel hemizygous R112L mutation in GLA gene.

LOXL1 gene analysis in Turkish patients with exfoliation glaucoma.

The purpose of this study is to evaluate whole lysyl oxidase like 1 (LOXL1) gene by sequence analysis in Turkish patients with exfoliation glaucoma (XFG). A total of 48 (35 male, 13 female) patients with XFG were enrolled. Besides routine ophthalmological examination, peripapillary retinal nerve fibre layer (RNFL) analysis with optic coherence tomography was performed. Blood samples of 2 ml with EDTA were obtained and sent to Medical Genetics Department, Molecular Genetics Laboratory for LOXL1 polymorphism (PCR and agarose gel imaging) analysis. The role of the detected changes on disease severity was evaluated. No LOXL1 gene mutations in any of the patients were detected. Three types of single-nucleotide polymorphisms (SNPs) including R141L(rs1048661), A320A(rs41435250), and F184F were detected in 17 (35.3 %) patients. When compared, SNP-positive patients had thinner RNFL than SNP-negative patients (64.5 ± 17.6 and 66.1 ± 20.4 µ, respectively), and SNP-positive patients had higher cupping/disc ratio than SNP-negative patients (0.76 ± 0.2 and 0.70 ± 0.3, respectively). However, both values were not statistically significant (p = 0.966 and p = 0.539, respectively). When compared, R141L-positive patients had significantly thinner cornea thickness (516.11 ± 30.3 µ) than R141L-negative patients (556.69 ± 27.2 µ) (p = 0.004). There was not any statistical significant difference in the means of age, gender, BCVA, MD, PSD, IOP, number of hypotensive agents, and percent of glaucoma surgery (p > 0.05). In this study group of Turkish population, no LOXL1 mutations were found. No associations between the defined SNPs (A320A, R141L and F184F) and the severity of the disease were detected.

The Results of Toric Intraocular Lens Implantation in Patients With Cataract and High Astigmatism After Penetrating Keratoplasty.

OBJECTIVES: To evaluate the results of toric intraocular lens (IOL) implantation in patients with cataract and postpenetrating keratoplasty astigmatism. METHODS: Seven eyes of 7 patients with cataract and more than 3.5 diopters (D) astigmatism following penetrating keratoplasty were included in this retrospective case series study. All of the eyes underwent phacoemulsification and Acrysof toric IOL (t5-t9) implantation at least 6 months later than the complete suture removal. Corrected visual acuity (CVA), manifest astigmatism, the keratometry measurements, and complications were assessed. RESULTS: The mean preoperative CVA significantly increased (0.7±0.3 [range: 0.3-1.3] logMAR to 0.1±0.04 [range: 0.05-0.15] logMAR; P<0.05) at mean 8.71±4.11 months after the surgery. The mean preoperative corneal astigmatism and the average manifest refractive astigmatism at the last visit were 5.4±0.9 D (range: 4.25-7 D) and 1.6±0.6 D (range: 0.5-2.5 D), respectively. The mean attempted cylinder correction at spectacle plane was 4.3±0.9 D (range: 2.4-4.7 D) whereas the mean cylinder correction was 4.6±0.5 D (range: 3.9-5.9 D), showing a slightly tendency for overcorrection. All eyes (100%) were within 1 D of predicted residual astigmatism. No complication occurred during the follow-up. CONCLUSION: Toric IOL implantation seems to be an effective, predictable, and safe procedure in patients with cataract formation and high astigmatism after penetrating keratoplasty.

The temperament and character personality profile of the glaucoma patient.

BACKGROUND: To determine the temperament and character profile of glaucoma patients. METHODS: A total of 234 patients (104 with primary open angle glaucoma, and 130 control subjects without any ocular disease) were selected for this prospective, cross-sectional study. All the participants underwent a comprehensive ophthalmological examination, including the best corrected visual acuity, intraocular pressure measurement, gonioscopy, and visual field analysis. All the participants were given the Turkish version of the Temperament and Character Inventory (TCI). The TCI is a self-reported evaluate, with 240 true/false items measuring four domains of temperament; harm avoidance (HA), persistence (PS), novelty seeking (NS), reward dependence (RD), and three domains of character; self-transcendence (ST), cooperativeness (C), self-directedness (SD). RESULTS: The glaucoma patients achieved the higher scores than the controls for the HA and SD dimensions (p < 0.001 and p = 0.033). The glaucoma patients scored lower than the controls for the NS, P and ST dimensions (p < 0.001, p < 0.001 and p = 0.002). There were no differences in the RD and C scores between the patients and the controls (p = 0.944 and p = 0.343). There was no correlation between the duration of illness and the TCI dimensions. Disease severity was positively associated with HA (r = 0,220, p = 0,025) and the anticipatory worry (r = 0.227, p = 0.021) dimension. CONCLUSIONS: Glaucoma patients had a different personality profile to healthy individuals. This may affect treatment compliance and is also important when coping with maladaptive patient attitudes.

Amiodarone-induced multiorgan toxicity with ocular findings on confocal microscopy.

Amiodarone is an antiarrhythmic medication that can adversely effect various organs including lungs, thyroid gland, liver, eyes, skin, and nerves. The risk of adverse effects increases with high doses and prolonged use. We report a 54-year-old female who presented with multiorgan toxicity after 8 months of low dose (200 mg/day) amiodarone treatment. The findings of confocal microscopy due to amiodarone-induced keratopathy are described. Amiodarone may cause multiorgan toxicity even at lower doses and for shorter treatment periods.

Does topical voriconazole trigger dysplastic changes on the ocular surface?

PURPOSE: Systemic voriconazole treatment was reported to cause photosensitivity and related cutaneous malignancies. The aim of this report is to demonstrate a graft-related Candida endophthalmitis case that developed ocular surface dysplastic changes after receiving topical 1% voriconazole treatment. METHODS: Full ocular examination, photography, and in vivo confocal microscopy examination (Rostock Cornea Module/HRT II, Heidelberg, Germany) were performed. RESULTS: A 73-year-old male with graft-related Candida endophthalmitis that was on topical 1% voriconazole for 4 months developed a whitish gelatinous lesion on the cornea originating from the nasal limbus. In vivo confocal microscopy examination revealed mild dysplastic changes in the cornea epithelium. CONCLUSION: Topical voriconazole might trigger neoplastic changes on the ocular surface as reported with systemic use in other sun-exposed parts of the body. Further studies are needed to relate topical use of voriconazole with ocular surface dysplasia.

Optic nerve and dura mater involvement as the first sign of multiple myeloma.

PURPOSE: To report a case of optic nerve and dura mater involvement as the first sign of multiple myeloma. METHODS: Case report. RESULTS: A 43-year-old woman presented with a headache and decreased vision in both eyes. Ophthalmic examination revealed anterior uveitis and subretinal mass around the optic nerves with accompanying disc edema bilaterally. Magnetic resonance imaging showed dural and optic nerve infiltration with tram-track enhancement in the optic nerve sheath. The diagnosis of multiple myeloma was made as a result of systemic investigations. The patient underwent systemic chemotherapy and cranial radiotherapy. After treatment, the patient's headache disappeared, the papilledema regressed, and the ocular findings improved but complete recovery could not be achieved because of fibrous subretinal tissue and degenerative changes of the optic nerve. CONCLUSIONS: Neurologic and ophthalmic involvement in multiple myeloma may appear as the first manifestation of disease. The correct diagnosis is important because it can be life-saving.

The effect of head rotation on intraocular pressure in prone position: a randomized trial.

BACKGROUND AND OBJECTIVES: The increased intraocular pressure (IOP) - which decreases perfusion pressure on the optic nerve - increases by prone positioning (1). The aim of our study was to compare the effect of head rotation 45° laterally in prone position on the increase in IOP of upper placed and lower placed eyes in patients undergoing percutaneous nephrolithotomy (PCNL). METHODS: Forty-five patients were randomly divided into 2 Groups. IOP of the patients were recorded bilaterally in supine position before the operation had started. Patients were turned to prone position. The head was placed on a prone headrest without external direct compression to both eyes. Patients in Group I were kept in strictly neutral prone position where as patients in Group II were placed prone with their heads rotated 45° laterally to the right side. At the end of the operation, patients were turned to supine position and their IOP was measured immediately. RESULTS: There was no difference related to demographics, duration of surgery, blood loss and fluid input data. IOP values after surgery in prone position increased significantly compared to preoperative values in both groups (p < 0.05). After surgery in prone position IOP values of the upper positioned eyes in Group II were significantly lower than Group I and lower positioned eyes in Group II (p < 0.05). CONCLUSION: prone positioning increases IOP. In patients with prone position with a head rotation of 45° laterally, IOP in the upper positioned eye was significantly lower.