Correlation between Central Corneal Thickness and Intraocular Pressure Measured by Goldmann Applanation Tonometry or Pascal Dynamic Contour Tonometry.

PURPOSE: The aim of this study was to investigate the relationship between central corneal thickness and intraocular pressure measured by Goldmann applanation tonometry and Pascal dynamic contour tonometry. PATIENTS AND METHODS: The study included 45 persons (90 eyes), divided into 4 groups: a) 10 normal volunteers (20 eyes); b) 16 patients (32 eyes) with primary open-angle glaucoma; c) 8 patients (16 eyes) with normal-tension glaucoma; and d) 11 patients (22 eyes) with ocular hypertension. Intraocular pressure was measured by Goldmann applanation tonometry and Pascal dynamic contour tonometry, and central corneal thickness was measured by ultrasound pachymetry. The relationship between intraocular pressure and central corneal thickness was evaluated. RESULTS: Intraocular pressure was correlated positively but not strongly enough with central corneal thickness when it was measured by Goldmann applanation tonometry. On the contrary, there was no correlation between intraocular pressure and central corneal thickness when intraocular pressure was measured by Pascal dynamic contour tonometry. CONCLUSION: Central corneal thickness is an important variable in the evaluation of intraocular pressure by Goldmann applanation tonometry. This factor does not interfere with the intraocular pressure measurements taken by Pascal dynamic contour tonometry.

Ocular pulse amplitude measurement using pascal dynamic contour tonometer in glaucoma patients.

AIM: This study aims to measure and compare the ocular pulse amplitude using Pascal dynamic contour tonometry in normal persons and in glaucoma patients. PATIENTS AND METHODS: 20 patients (40 eyes) with primary open angle glaucoma (Group A), 8 patients (16 eyes) with normal tension glaucoma (Group B), and 12 patients (24 eyes) with ocular hypertension (Group C) were included in the study. Control group (Group D) comprised 25 normal volunteers (50 eyes). Intraocular pressure was measured using both Goldmann applanation tonometry in the slit-lamp and Pascal dynamic contour tonometry. Ocular pulse amplitude was evaluated with Pascal dynamic contour tonometry. Statistical evaluation of the differences in ocular pulse amplitude and intraocular pressure among the different groups was performed using Student's t-test. RESULTS: Mean ocular pulse amplitude values expressed in mmHg were 3.66 ± 1.00, 2.46 ± 0.60, 4.04 ± 1.47, and 2.52 ± 0.52, for Groups A, B, C, and D, respectively. The ocular pulse amplitude was significantly higher in Group A (primary open angle glaucoma) and Group C (ocular hypertension) when compared with Group D (control group) and Group B (normal tension glaucoma). No statistically significant difference was detected between Group D (control group) and Group B (normal tension glaucoma). CONCLUSIONS: Although we can measure the intraocular pressure with Goldmann applanation tonometry, no information can be derived regarding the ocular pulse amplitude. The use of Pascal dynamic contour tonometry in intraocular pressure estimation provides useful clinical information also about the magnitude of the ocular pulse amplitude in different types of glaucoma. Pascal dynamic contour tonometry discloses an elevation of ocular pulse amplitude in primary open angle glaucoma and ocular hypertension patients. On the contrary, the ocular pulse amplitude is within normal limits in normal tension glaucoma patients.

Central foveal thickness before and after cataract surgery in normal and in diabetic patients without retinopathy.

BACKGROUND: This study aims to evaluate and compare central foveal thickness (CFT) changes after cataract surgery between normal and diabetic patients without retinopathy, using optical coherence tomography (OCT). PATIENTS AND METHODS: Ninety-eight patients (49 patients with type 2 diabetes and 49 healthy controls, sex- and age-matched) undergoing phacoemulsification in one eye were included. The presence of retinopathy was an exclusion criterion. The OCT examination was performed preoperatively as well as one, three, six and twelve months postoperatively. CFT was evaluated and compared between groups. RESULTS: Preoperative CFT showed no significant difference between the two groups (normals: 205 ± 18 µm vs. diabetics: 202 ± 23 µm, p > 0.1). Postoperative CFT in diabetics at all time-points of the follow-up period was significantly increased when compared to controls (first month, normals: 215 ± 28 µm vs. diabetics: 262 ± 33 µm, p < 0.05; third month, normals: 211 ± 19 µm vs. diabetics: 250 ± 27 µm, p < 0.05; sixth month, normals: 208 ± 12 µm vs. diabetics: 266 ± 13 µm, p < 0.05; and twelfth month, normals: 209 ± 13 µm vs. diabetics: 280 ± 11 µm, p < 0.05). The incidence of cystoid macular edema (CME) was 4.0 % and 28.6 % for the control group and the diabetic group, respectively, at the end of the follow-up period (p < 0.05). CONCLUSION: Eyes of diabetic patients without retinopathy present higher CFT and a higher incidence of CME after cataract surgery on OCT examination compared to eyes of healthy controls. This may explain the unsatisfactory visual acuity following cataract surgery in these patients.

Effect of brimonidine/timolol fixed combination on preventing the short-term intraocular pressure increase after intravitreal injection of ranibizumab.

BACKGROUND: The aim of this study was to evaluate the safety and efficacy of brimonidine 0.2 % and timolol 0.5 % instillation as a fixed combination (Combigan, Allergan Inc.) to prevent acute intraocular pressure (IOP) increase occurring after intravitreal injection of ranibizumab (Lucentis, Novartis Pharma AG). PATIENTS AND METHODS: A prospective double-blind placebo-controlled study was carried out. One eye of 88 consecutive normotensive age-related macular degeneration patients receiving Lucentis was randomized into placebo drops (artificial tears, 44 patients) or Combigan drops (44 patients) given twice a day the day before and the day of injection. IOP was measured before and 5, 10, 15 minutes and 1 hour after the intravitreal injection. RESULTS: The placebo group had the higher mean IOP at all time points after injection. Maximum IOP increase for both groups occurred at the 5-minutes time point. Mean post-injection IOP in the placebo group was 34.1 +/- 2.7 mmHg at 5 minutes post-injection versus 28.4 +/- 1.1 mmHg in the Combigan group (P < 0.001). IOP decreased to 24.9 +/- 1.8 mmHg (placebo group) and 19.9 +/- 1.1 mmHg (Combigan group) at 10 minutes post-injection. At 15 minutes post-injection, IOP was below 20 mmHg in all eyes of the Combigan group (100 %), whereas at the same time point these IOP levels were reached only by 34 % of the eyes of the placebo group (15 eyes). All eyes of both groups had a normal IOP 1 hour post-injection. No systemic or ocular side effect was recorded in either group. CONCLUSIONS: The use of Combigan drops twice a day the day before and the day of injection in eyes scheduled for intravitreal injection of Lucentis is a safe and effective prophylaxis to reduce the acute IOP spikes of the post-injection period.

Cilioretinal artery occlusion combined with central retinal vein occlusion - a report of two cases and review of the literature.

BACKGROUND: We describe the clinical findings and course of cilioretinal artery occlusion (CAO) combined with central retinal vein occlusion (CRVO) in two patients and present a review of the relevant literature. HISTORY AND SIGNS: Case 1: An otherwise healthy 24-year-old woman presented to the emergency unit with a painless visual decrease in her right eye. Fundus examination revealed retinal edema due to CAO in association with signs of venous stasis. Fluorescein angiography (FA) showed a patent cilioretinal artery. Case 2: A heavy smoker, hypertensive, 59-year-old man was referred for sudden visual loss in his left eye. Fundus examination and FA revealed CAO and CRVO. THERAPY AND OUTCOME: No treatment was applied for the first patient. Two weeks after diagnosis, retinal edema had subsided and only the signs of venous stasis were evident. The central scotoma remained unchanged. In the second patient, within the next three months, the development of retinal ischemia led to retinal neovascularization. Panretinal photocoagulation was applied. Visual acuity remained very low (light perception). CONCLUSIONS: The combination of CAO and CRVO comprises a discrete clinical entity. In both our cases, FA did not show full obstruction of the cilioretinal artery. Even though many hypotheses have been postulated about this entity, it seems that it ensues from the increased intraluminal pressure in the retinal capillaries (due to the CRVO), which exceeds the pressure in the cilioretinal artery. Thus, it is probably a functional obstruction of the cilioretinal artery, although its pathogenesis remains controversial.

Hydrogel intraocular lens exchange: five-year experience.

BACKGROUND: This study presents an evaluation of the preoperative and postoperative best corrected visual acuity (BCVA), as well as of the incidence of perioperative and postoperative complications after opacified hydrogel intraocular lens (IOL) exchange. PATIENTS AND METHODS: We exchanged opacified hydrogel IOLs (Hydroview H 60 M, Bausch & Lomb) in 55 patients (55 eyes). Preoperative and postoperative BCVA were compared. Intraoperative and postoperative complications were recorded. Follow-up period ranged from 3 months to 24 months. RESULTS: Mean BCVA improved significantly from 0.05 preoperatively to 0.4 at 3 months postoperatively and to 0.2 at the end of the follow-up period. Forty patients (72.7 %) reported visual improvement. The procedure was uneventful in 30 eyes (54.5 %) with complete removal of the opacified IOL optics and haptics. Intraoperative complications included partial zonular dehiscence in 10 eyes (18.2 %), en block capsular bag-IOL extraction in 2 eyes (3.6 %), posterior capsule rupture in 2 eyes (3.6 %), hyphema in 3 eyes (5.5 %), retained haptics in 8 eyes (14.5 %). Postoperative complications included corneal decompensation in 5 eyes (9.1 %), cystoid macular edema in 15 eyes (27.3 %), elevated intraocular pressure in 6 eyes (10.9 %), and retinal detachment in 1 eye (1.8 %). CONCLUSIONS: Visual acuity improved after opacified hydrogel IOL exchange, however, coexistent ocular morbidity as well as the appearance of serious postoperative complications may not yield the expected results. For these reasons extensive informed consent is mandatory.

Late postoperative opacification of hydrogel intraocular lenses: analysis of 13 explanted lenses.

PURPOSE: We report the clinical, morphological, and ultrastructural findings of 13 consecutively explanted opacified Hydroview(R) (hydrogel) intraocular lenses (IOLs). Our purpose was to provide a comprehensive account on the possible factors involved in late postoperative opacification of these IOLs. PATIENTS AND METHODS: Thirteen consecutive opacified hydrogel IOLs (Hydroview H 60 M, Bausch & Lomb) were explanted due to the significant visual impairment they caused. The IOLs underwent macroscopical examination, transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and electrophoresis for protein detection. Three unused control Hydroview IOLs served for comparison. RESULTS: Macroscopical examination showed a diffuse or localized grey-whitish opacification within the IOL optic. TEM confirmed the presence of lesions inside the optic in all the explanted IOLs and revealed 3 patterns of deep deposits: a) diffuse, thick, granular, electron-dense ones; b) small, thin, lattice-like ones, with prominent electron-lucent areas; and c) elongated electron-dense formations surrounded by electron-lucent halos. SEM showed surface deposits on four IOLs. EDS revealed oxygen and carbon in all IOLs and documented calcium, phosphorus, silicon and/or iron in the deposits. Two of the patients with iron in their IOLs had eye surgery prior to their phacoemulsification. Iron correlated well with the second TEM pattern of deep lesions, whereas calcium with the third TEM pattern. No protein bands were detected on electrophoresis. Control lenses did not show any ultrastructural or chemical abnormality. CONCLUSIONS: The present study supports the presence of chemical alterations inside the polymer of the optic in late postoperative opacification of Hydroview IOLs. This opacification does not follow a unique pathway but may present under different ultrastructular patterns depending on the responsible factors. Mechanical stress during surgery may initiate a sequence of events where ions such as calcium, phosphorus, silicon, and/or iron, participate in a biochemical cascade that leads to gradual alteration of the polymer network. Intraocular inflammation due to previous operation may be a factor inducing opacification through increase of iron-binding capacity in the aqueous humour. Calcification accounts only partially for the opacification noted in this type of IOL.

Congenital retinal macrovessels: description of three cases and review of the literature.

BACKGROUND: Congenital retinal macrovessels are large aberrant branches of retinal arteries or veins that cross the macula. We present three patients with a unilateral congenital retinal macrovessel and we conduct a review of the literature. PATIENTS AND METHODS: A 22-year-old man complaining of chronic headache as well as two other men, 18 and 23 years old, respectively, during a routine ophthalmological examination, were found with a unilateral congenital retinal macrovessel each. A thorough ophthalmological examination was performed, including colour fundus photography in all three patients and fluorescein angiography in two of the patients. We followed them up for five years. THERAPY AND OUTCOME: Investigation revealed a unilateral venous congenital retinal macrovessel in all patients. Clinical findings and visual acuity remained unchanged throughout the entire follow-up period. No complications were recorded. CONCLUSIONS: Congenital retinal macrovessels are rare and they tend to remain stable. Visual acuity is preserved in most cases. Complications occur only occasionally and have been described in the literature. Differential diagnosis from other arteriovenous malformations affecting multiple organs is necessary.