Impact of Refractive Errors on Da Vinci SI Robotic System.

OBJECTIVE: To investigate the impact of refractive errors on binocular visual acuity while using the Da Vinci SI robotic system console. METHODS: Eighty volunteers were examined on the Da Vinci SI robotic system console by using a near vision chart. Refractive errors, anisometropia status, and Fly Stereo Acuity Test scores were recorded. Spherical equivalent (SE) were calculated for all volunteers' right and left eyes. Visual acuity was assessed by the logarithm of the minimal angle of resolution (LogMAR) method. Binocular uncorrected and best corrected (with proper contact lens or glasses) LogMAR values of the subjects were recorded. The difference between these values (DiffLogMAR) are affected by different refractive errors. RESULTS: In the myopia and/or astigmatism group, uncorrected SE was found to have significant impact on the DiffLogMAR (p < 0.001) and myopia greater than 1.75 diopter had significantly higher DiffLogMAR values (p < 0.05). Subjects with presbyopia had significantly higher DiffLogMAR values (p < 0.01), and we observed positive correlation between presbyopia and DiffLogMAR values (p = 0.33, p < 0.01). The cut off value of presbyopia that correlated the most with DiffLogMAR differences was found to be 1.25 diopter (p < 0.001). In 13 hypermetropic volunteers, we found significant correlation between hypermetropia value and DiffLogMAR (p > 0.7, p < 0.01). The statistical analysis between Fly test and SE revealed a significant impact of presbyopia and hypermetropia to the stereotactic view of the subject (p = -0.734, p < 0.05). CONCLUSION: Surgeons suffering from myopia greater than 1.75 diopter, presbyopia greater than 1.25 diopter (D), and hypermetropia regardless of grade must always perform robotic surgeries with the proper correction.

The effect of hemodialysis on intraocular pressure.

BACKGROUND: The effect of hemodialysis (HD) on intraocular pressure (IOP) has been investigated before, but there is a lack of consensus. Clinicians dealing with renal failure patients are interested in the potential negative effects of HD on IOP and the course of glaucoma. OBJECTIVES: The aim of this study was to investigate the effects of HD on IOP in patients with end-stage renal disease. MATERIAL AND METHODS: This prospective study included 106 patients who were receiving outpatient hemodialysis. Patient history of systemic and ophthalmologic conditions was recorded. Serum osmolality (mOsm), blood urea nitrogen (BUN), blood glucose (BG), bicarbonate (BC), and hematocrit (Hct) levels at the start of HD (pre-HD), at the end of HD (end-HD), and 30 min after HD (post-HD) were measured. Systolic and diastolic blood pressures (SBP and DBP) and IOP were measured at pre-HD, 1-hour intervals during HD, end-HD, and post-HD. RESULTS: A significant decrease in mOsm and BUN and a significant increase in BG, BC, and Hct levels were observed at end-HD (p < 0.05). Mean IOP was 16.71 ±2.51 mm Hg at pre-HD, 15.52 ±3.18 mm Hg at endHD, and 15.23 ±2.73 mm Hg at post-HD (p = 0.001; F = 4.439). Post-HD SBP and DBP were significantly lower than at pre-HD (p < 0.001). There was a positive correlation between the change in IOP and the change in mOsm and the change in BUN at end-HD (r = 0.315, p = 0.004; and r = 0.279, p = 0.012, respectively). CONCLUSIONS: IOP decreased significantly during HD in this study. Additional research on the effects of the change in blood parameters and ocular perfusion pressure on IOP and optic nerve perfusion during HD is recommended.

Estrogen- and Progesterone-Induced Variation in Corneal Parameters According to Hormonal Status.

OBJECTIVES: To determine the effects of estrogen and progesterone on corneal thickness, curvature, and biomechanics in healthy corneas according to hormonal status. METHODS: The study included four groups of females: group A (menstruating, not pregnant, not lactating, and not menopausal; n=100), group B (pregnant; n=50), group C (lactating; n=50), and group D (menopausal; n=50). Group A was subdivided according to age, as subgroup A15-25 (age 15-25 years) and subgroup A>25 (age >25 years). Blood estradiol and progesterone levels were measured in each participant. All the participants underwent a full ophthalmologic examination, including corneal thickness and corneal topography measurement, and evaluation of corneal biomechanical properties. RESULTS: The corneal resistance factor and anterior corneal flat keratometry values were significantly higher in group D (P=0.040 and P=0.026, respectively) than in the other three groups. Posterior corneal steep keratometry values were significantly higher in subgroup A>25 during the preovulatory phase than ovulatory and postovulatory phases (P=0.012). In group B, there was a significant negative correlation between gestational week and intraocular pressure (IOP) (r=-0.322, P=0.024). Corneal volume was significantly higher during the early postpartum period than the late postpartum period in group C (P=0.028). Intraocular pressure, Goldman-correlated IOP, and corneal-compensated IOP differed significantly between the groups (P<0.05). CONCLUSIONS: Blood levels of estrogen and progesterone were associated with variations in IOP, but estrogen and progesterone did not have a consistent effect on topographic parameters or biomechanical properties in healthy corneas.

Age-related change in corneal biomechanical parameters in a healthy Caucasian population.

PURPOSE: To determine the effect of aging on corneal biomechanical parameters measured via ocular response analyzer in a homogenous healthy Caucasian population. METHODS: A total of 2039 Caucasian adults were consecutively recruited and divided into seven groups according to decades of age. The difference in mean corneal hysteresis (CH), mean corneal resistance factor (CRF), mean Goldmann-correlated intraocular pressure (IOPg), and mean corneal-compensated IOP (IOPcc) between decades of age were investigated. The strength of the correlations between corneal biomechanical parameters, and between each biomechanical parameter and age were evaluated. The effect of age on each corneal biomechanical parameter was analyzed. RESULTS: Mean age of the participants (1173 female and 866 male) was 43.30 ± 14.64 years. Mean CH, CRF, IOPcc, and IOPg were 11.49 ± 1.89 mmHg, 11.40 ± 2.30 mmHg, 15.01 ± 3.11 mmHg, and 15.72 ± 3.80 mmHg, respectively. There were significant differences in mean CH, CRF, IOPcc, and IOPg between groups (p < 0.001 for all parameters). There was a significant negative correlation between age and CH (r = -0.067 and p = 0.003), and a significant negative correlation between age and CRF (r = -0.053 and p = 0.017). There was a significant positive correlation between age and IOPg (r = 0.25 and p < 0.001), and between age and IOPcc (r = 0.20 and p < 0.001). Linear regression analysis showed that for every 1-year increase CH decreased 0.011 mmHg, CRF decreased 0.004 mmHg, IOPcc increased 0.053 mmHg, and IOPg increased 0.047 mmHg. CONCLUSIONS: Aging can cause significant changes in corneal biomechanical parameters. Corneal biomechanical parameters were correlated with each other, and each was correlated with aging.

A sample predictive model for intraocular pressure following laser in situ keratomileusis for myopia and an "intraocular pressure constant".

PURPOSE: To describe a sample predictive model for intraocular pressure (IOP) following laser in situ keratomileusis (LASIK) for myopia and an IOP constant. METHODS: The records of patients that underwent LASIK for myopia and myopic astigmatism via WaveLight Allegretto Wave Eye-Q 400 Hz excimer laser and Hansatome XP microkeratome were retrospectively reviewed. Patients with no systemic or ocular disease other than myopia or myopic astigmatism were included in the study. Preoperative and postoperative month 1 data and intraoperative data were used to build the predictive model for IOP after LASIK. The IOP constant was calculated by subtracting the predicted IOP from preoperative IOP. The paired samples t test, Pearson's correlation analysis, curve estimation analysis, and linear regression analysis were used to evaluate the study data. RESULTS: The study included 425 eyes in 214 patients with a mean age of 32 ± 7.8 years. Mean spherical equivalent of the attempted correction (SE-ac) was -3.7 ± 1.7 diopters. Mean post-LASIK decrease in IOP was 4.6 ± 2.3 mmHg. The difference between preoperative and postoperative IOP was statistically significant (P < 0.001). SE-ac, preoperative IOP, and central corneal thickness had highly significant effects on postoperative IOP, based on linear regression analysis (P < 0.001 and R 2 = 0.043, P < 0.001 and R 2 = 0.370, and P < 0.001 and R 2 = 0.132, respectively). Regression model was created (F = 127.733, P < 0.001), and the adjusted R 2 value was 0.548. CONCLUSIONS: Evaluation of IOP after LASIK is important in myopic patients. The present study described a practical formula for predicting the true IOP with the aid of an IOP constant value in myopic eyes following LASIK.

An 11-Year Review of Keratoplasty in a Tertiary Referral Center in Turkey: Changing Surgical Techniques for Similar Indications.

OBJECTIVES: Study aims to evaluate the indications and surgical techniques for corneal transplantation and to report changes in trends for preferred keratoplasty surgical techniques. METHODS: Clinical records of 815 consecutive corneal transplantations between January 1, 2004 and December 31, 2014 in Haydarpasa Numune Training and Research Hospital Eye Clinic were analyzed and classified into seven broad groups according to indications. Main outcome measures were change of leading indications and trends for surgical techniques. RESULTS: Leading indications for keratoplasty were keratoconus (KCN) (27.7%), bullous keratopathy (BK) (23%), postinfectious corneal scars (13.5%), regrafts (13.1%), corneal dystrophies (12.1%), and noninfectious corneal scars (5.4%). Regrafts were the only indication with a significantly increasing trend (P<0.01). Since the introduction of lamellar keratoplasty (LK) techniques including deep anterior lamellar keratoplasty (DALK) and Descemet stripping automated endothelial keratoplasty (DSAEK), there was a significant increasing trend in number and percentage of both LK techniques (DALK; P=0.001 and P=0.007, and DSAEK; P<0.001 and P<0.001, respectively) and a significant corresponding decline in the percentage of penetrating keratoplasty (PK) (P<0.01). Similarly, DALK and DSAEK replaced PK as the preferred surgical technique for KCN and BK indications, (P=0.007 and P=0.01, respectively). Although PK was the most common surgical technique over the 11-year period (54.7%), both anterior and posterior LK techniques showed an emerging trend as the procedures of choice when indicated. CONCLUSIONS: No major shift was observed in the clinical indications for corneal transplantation over the previous 11 years, except for regrafts. Lamellar keratoplasty techniques largely overtook the PK technique, but PK was still the overall preferred technique in the era when both LK techniques were used.

The Effect of Smoking on Corneal Biomechanics.

PURPOSE: To determine the effect of smoking on corneal biomechanical behavior. MATERIALS AND METHODS: The medical records of consecutive patients that presented to the ophthalmology department were reviewed. History of smoking and ophthalmological examination findings were recorded. The smoking group met the following criteria: a clear history of and present smoking habit, negative history of corneal disease and surgery, ocular response analyzer measurement at the time of examination, and a waveform score ≥3.7. Nonsmokers (never smoked or quit smoking ≥6 months earlier) that met the same criteria constituted the control group. Corneal biomechanical parameters were measured using ocular response analyzer. Data were analyzed using Pearson's χ2 test, Mann-Whitney U test, and Spearman's correlation coefficient. RESULTS: The smoking group included 166 eyes of 166 patients with a mean age of 38.7 ± 11.95 years, and the control group consisted of 170 eyes of 170 patients with a mean age of 38.40 ± 12.2 years. Mean cumulative smoking dose in the smoking group was 9.59 ± 11.87 pack-years (0.04- 75.00). There was no significant correlation between cumulative smoking dose and corneal hysteresis and corneal resistance factor (P = 0.382 and 0.074, respectively). There were no significant differences in corneal hysteresis or the corneal resistance factor between the two groups (P > 0.05). There was no significant difference in corneal hysteresis between those in the smoking group aged 18-44 years and those aged 45-64 years (P = 0.258), whereas in the control group mean corneal hysteresis was significantly lower in the 45-64 year olds than in the 18-44 year olds (P = 0.034). CONCLUSIONS: Although there was no significant difference in corneal biomechanics between smoking and control groups, the decrease in corneal hysteresis with aging was less apparent in the smoking group, which may be due to the potential changes in the cornea's microstructure induced by smoking during aging and the effect of smoking in aged corneal tissue viscosity.

The role of anterior segment optical coherence tomography in the management of an intra-corneal foreign body.

INTRODUCTION: Corneal foreign bodies are reported to be the second most common type of ocular injury. Anterior segment optical coherence tomography (AS-OCT) is a valuable tool for the early diagnosis and monitoring the progress of treatment in cases of ocular trauma. Herein we aimed to report on a patient with an intra-corneal foreign body and the role of AS-OCT in management. CASE PRESENTATION: A 34-year-old male presented with foreign body sensation in his left eye. Slit-lamp biomicroscopic examination revealed a peripherally located intrastromally embedded foreign body with a free anterior edge extending outwards from the cornea. It was not possible to visualize the foreign body's entire route through the cornea because of localized corneal edema. AS-OCT showed shadowing of the corneal layers corresponding to the location of the corneal foreign body. A hyper-reflective lesion was observed close to the inside edge of the foreign body in the cornea, indicating that the foreign body had not completely penetrated the cornea. The foreign body was removed via the external route, as it had not completely penetrated the cornea. During the postoperative period the patient was asymptomatic, although the left eye's cornea healed with scar tissue. DISCUSSION AND EVALUATION: AS-OCT facilitates non-invasive rapid imaging of ocular tissue at va rious depths, thereby providing accurate assessment of foreign body characteristics.The location of an intracorneal foreign body and the status of the surrounding ocular structure dictate the optimal surgical technique to be employed. CONCLUSIONS: AS-OCT in the present case facilitated localization and determination of the size of a corneal foreign body. In addition, AS-OCT findings assisted in selection of the appropriate surgical intervention.

Treatment of mixed astigmatism: early clinical outcomes withWaveLight and Technolas excimer lasers.

BACKGROUND/AIM: We aimed to compare the results of WaveLight Allegretto Wave Eye-Q 400 Hz and Technolas 217z100 excimer lasers in the treatment of mixed astigmatism. MATERIALS AND METHODS: Forty-nine patients who underwent laser in situ keratomileusis for mixed astigmatism were included in this retrospective study. Twenty-eight eyes of 21 patients were treated with WaveLight and 46 eyes of 28 patients were treated with the Technolas excimer laser. The patients' visual acuities and refractive values were evaluated on postoperative day 1 and at 1 and 3 months. RESULTS: In the WaveLight and Technolas groups, cylindrical refractive errors at month 3 were -0.92 ± 0.28 D and -0.88 ± 0.46 D, respectively. Spherical equivalent values for the groups at month 3 were -0.38 ± 0.73 D and -0.33 ± 0.20 D, respectively. There was no significant difference in postoperative uncorrected distance visual acuity at month 3 between the two groups (P = 0.671). At postoperative month 3, 70% of patients treated with WaveLight and 100% of patients treated with Technolas had an uncorrected distance visual acuity of 20/25 or better (P = 0.211). CONCLUSION: There were no significant differences in refraction and visual acuity between the WaveLight and Technolas groups during a 3-month follow-up period after laser in situ keratomileusis for mixed astigmatism.

Hyperbaric oxygen for the treatment of the rare combination of central retinal vein occlusion and cilioretinal artery occlusion.

A 43-year-old male presented with sudden onset of painless, blurred vision in his left eye. Dilated fundoscopic examination showed signs consistent with the diagnosis of a combination of central retinal vein occlusion (CRVO) and cilioretinal artery occlusion (CLRAO). He received daily 2-h sessions of hyperbaric oxygen treatment (HBOT), 253 kPa for 14 days. At the end of the HBOT course, the patient's left visual acuity had improved from 20/200 to 20/20. Dilated fundoscopic examination showed that the intra-retinal haemorrhages in the entire retina and the retinal whitening along the course of the CLRA seen at presentation had completely resolved. The combination of CLRAO and CRVO comprises a discrete clinical entity. Even though there are many hypotheses concerning this condition, it is most likely the result of elevated intraluminal pressure in the retinal capillaries due to CRVO that exceeds the pressure in the CLRA. HBOT may be an effective treatment for CRVO-associated CLRAO.

Iris metastasis of gastric adenocarcinoma.

BACKGROUND: Iris metastasis in patients with gastric cancer is extremely rare. Herein, it is aimed to report on a patient with gastric adenocarcinoma and iris metastasis. CASE PRESENTATION: A 65-year-old patient with the history of gastric cancer was admitted for eye pain and eye redness on his left eye. There was ciliary injection, severe +4 cells with hypopyon in the anterior chamber and a solitary, friable, yellow-white, fleshy-creamy vascularized 2 mm × 4 mm mass on the upper nasal part of the iris within the left eye. The presented patient's mass lesion in the iris fulfilled the criteria of the metastatic iris lesion's appearance. The ocular metastasis occurred during chemotherapy. CONCLUSIONS: Iris metastasis can masquerade as iridocyclitis with pseudohypopyon or glaucoma. In patients with a history of gastric cancer that present with an iris mass, uveitis, and high intraocular pressure, ocular metastasis of gastric cancer should be a consideration.

Corneal Biomechanical Properties in Aspirin Users.

PURPOSE: To analyze corneal biomechanical properties in aspirin users using an ocular response analyzer. METHODS: This study included 80 eyes of 40 aspirin users and 80 eyes of 40 individuals who did not use aspirin. Corneal hysteresis (CH), the corneal resistance factor (CRF), Goldman-correlated intraocular pressure (IOPg), and corneal compensated intraocular pressure (IOPcc) were measured in all participants. The independent samples t test was used to compare measurements in the aspirin users and nonusers in the total study population, and in the diabetic patient subgroup. Pearson's correlation analysis was used to examine the relationship between the measured variables in the aspirin users and nonusers. RESULTS: Aspirin users (59.08 ± 11.83 years) were older than nonusers (39.82 ± 12.97 years; p < 0.001). The mean CH was significantly lower in the aspirin user group than in the nonuser group (p = 0.013). Mean IOPg and mean IOPcc were also significantly higher in the aspirin user group (p = 0.027 and p = 0.002, respectively). The mean CRF was lower in the aspirin user group, but not significantly (p = 0.70). There was a positive correlation between CH and CRF (r = 0.767, p < 0.001), and between CRF and IOPg (r = 0.680, p < 0.001), and a negative correlation between CH and IOPcc (r = -0.415, p < 0.001). CONCLUSIONS: Aspirin should be taken into account when interpreting the results of corneal biomechanical measurements.

Retinal tear: an unusual complication of ocular toxoplasmosis.

PURPOSE: It is aimed to report on a 16-year-old patient with acquired ocular toxoplasmosis complicated by a retinal tear. METHODS: Retrospective medical chart review. RESULTS: A 16-year-old Caucasian female presented with vision loss in her right eye. In addition to a white active lesion between the fovea and the optic nerve head, marked vitreous opacification was noted. She was diagnosed with ocular toxoplasmosis. The patient was treated with oral azithromycin, clindamycin, and trimethoprimsulfamethoxazole. One month later, retinochoroiditis resolved and vitreous cleared. Three months after onset, patient presented with floaters in the right eye and a retinal tear was located at the temporal region of the retina. Prophylactic argon laser treatment that encircled the retinal tear was performed. No other abnormalities were noted during 6 months of follow-up. CONCLUSIONS: Retinal tear associated with ocular toxoplasmosis is rare; however, a retinal tear can occur due to vitreoretinal traction following post-inflammatory structural alteration of the vitreous. Retinal tears may be seen during the healing phase, when the inflammation turns into tightening of vitreous substance. Careful retinal examination in cases of ocular toxoplasmosis is warranted, especially in patients with severe vitreous inflammation.