Outcomes of refractive error correction in pseudophakic patients using a sulcus piggyback intraocular lens.

PURPOSE: The purpose of this study was to assess the results of a sulcus intraocular lens (Sulcoflex) for pseudophakic refractive errors following phacoemulsification cataract surgery. METHODS: This retrospective clinical observational cohort study included consecutive eyes in which a Sulcoflex was implanted. Uncorrected distance visual acuity and corrected distance visual acuity as well as refractive outcomes were assessed. The minimum follow-up time required for inclusion was 3 months. RESULTS: In total, 15 eyes (n = 15) were evaluated. The mean follow-up was 14 months (range: 3-18 months). The Sulcoflex aspheric (653L) was implanted in 13 eyes and the Sulcoflex toric (653T) in two eyes. The preoperative mean logMAR (Snellen) uncorrected distance visual acuity and corrected distance visual acuity were 0.88 (20/150) and 0.27 (20/40), respectively. The postoperative mean logMAR (Snellen) corrected distance visual acuity was 0.15 (20/30). The preoperative mean spherical equivalent was -0.22 ± 5.95 D and the postoperative mean spherical equivalent was -1.59 ± 1.45 D. There was a significant and strong correlation (r = 0.64, p < 0.001) between the attempted and the achieved spherical equivalent. CONCLUSION: The Sulcoflex is a safe and viable option for patients with residual refractive error following cataract surgery.

Retinal Toxicity of Intravitreal Injection of Ziv-Aflibercept in Albino Rabbits.

PURPOSE: To evaluate retinal toxicity of ziv-aflibercept, a drug that had been approved for use for patients with colon cancer. METHODS: Twenty-two albino rabbits were injected intravitreally with 0.1 mL of ziv-aflibercept solution into the experimental eye and 0.1-mL saline into the control eye. Twelve were used for electroretinogram (ERG) at 4-weeks follow-up. An additional 10 rabbits were used for testing penetration of ziv-aflibercept into the retina during follow-up. The visual-evoked potential (VEP) was recorded after 4 weeks of ERG follow-up. Glial fibrillary acidic protein (GFAP) immunocytochemistry and retinal histology were performed after the termination of the follow-up period. RESULTS: The ERG responses of the experimental eyes did not show signs of permanent functional damage. The VEP responses of the experimental eyes were of normal pattern and amplitude, and were similar to those recorded by stimulation of the control eyes. Histologic studies of both experimental and control eyes did not show signs of structural damage. However, GFAP expression was increased in retinal Müller cells of the experimental eyes and not of the control eyes. Retinal penetration of ziv-aflibercept, as indicated by positive antihuman immunoreactivity, was observed 1 day postinjection and was strengthened during the next 7 days. At 14 days postinjection, ziv-aflibercept was not detected. CONCLUSIONS: Ziv-aflibercept was found to be nontoxic to the retina of rabbits based on electrophysiologic testing and histologic examination. However, GFAP immunocytochemistry suggests mild retinal stress caused by the drug. TRANSLATIONAL RELEVANCE: If proven safe, ziv-aflibercept may be a new affordable treatment option in conditions involving neovascularization and macular edema.

Intravitreal Trimethoprim and Sulfamethoxazole Toxicity to the Retina of Albino Rabbits.

PURPOSE: To evaluate retinal toxicity of intravitreal trimethoprim-sulfamethoxazole (TMP-SMX) in an albino rabbit model. METHODS: Albino rabbits (N = 10) were treated in the right eye with the maximum intravitreal dose of TMP-SMX mixture (1600 µg/8000 µg /0.1 mL), while 0.1 mL saline was injected into the vitreous of the left eye. Clinical examination and electrophysiological (electroretinogram [ERG] and visual evoked potentials [VEPs]) testing were conducted before injection, 3 days, 1, 2, and 4 weeks postinjection. Retinal structure and expression of glial fibrillary acidic protein (GFAP) were assessed from histology and immunocytochemistry respectively at the end of the follow-up period. RESULTS: Clinical examination was normal throughout the follow-up period. ERG responses from the experimental eyes were similar to those recorded from the control eyes, but the sum of oscillatory potentials decreased in the experimental eyes at 2 weeks postinjection. The VEP responses, elicited by stimulation of the experimental eyes, were abnormal having reduced amplitude and prolonged implicit time. Histological damage in the experimental eyes was expressed by thickness reduction of whole, outer, and inner nuclear layers. GFAP was expressed in retinal Müller cells of all experimental eyes, but none of control eyes. CONCLUSIONS: A single intravitreal injection of TMP-SMX mixture (1600 µg/8000 µg, respectively) causes functional and structural damage to the inner retina and retinal output. Signs of retinal stress were also evident by GFAP expression in retinal Müller cells of all experimental eyes. Therefore, the use of TMP-SMX via intravitreal administration should be done with caution. TRANSLATIONAL RELEVANCE: These findings highlight the risk of retinal toxicity after intravitreal injection of trimethoprim-sulfamethoxazole and emphasize that this treatment should be carefully considered.

Safety of intravitreal clindamycin in albino rabbit eyes.

PURPOSE: To study the potential toxic effects of intravitreal clindamycin on the retina of albino rabbits, by assessing functional and morphological retinal changes. METHODS: Eight albino rabbits were included in the study. In each rabbit, 1 mg/0.1 ml clindamycin was injected into the vitreous of the right (experimental) eye, and 0.1 ml saline was injected into the vitreous of the left (control) eye. The electroretinogram (ERG) was recorded before injection, 3 days, 1, 2, and 4 weeks post-injection. The visual evoked potential (VEP) was recorded 4 weeks post-injection. Clinical examination was conducted at all time points. The eyes were enucleated at the termination of the follow-up period in order to prepare the retinas for histology in order to assess retinal structure. RESULTS: ERG and VEP responses that were recorded from the experimental eye at different times following intravitreal clindamycin injection were very similar to the corresponding responses that were recorded from the control eyes. Clinical examination was normal in all eyes, and no histological damage was observed. CONCLUSIONS: Intravitreal injection of 1 mg clindamycin does not cause functional or morphological signs of retinal toxicity in albino rabbits, during a period of 4 weeks post-injection. These findings support the clinical use of 1 mg intravitreal clindamycin.

Effect of pupil size on biometry measurements using the IOLMaster.

PURPOSE: To evaluate the effect of pupil dilation on biometric measurements and intraocular lens power calculation using the IOLMaster (Carl Zeiss Meditec). DESIGN: Prospective, observational case series. METHODS: In this prospective study, 2 consecutive optical biometry measurements, before and after pupil dilation, were obtained using the IOLMaster on 318 eyes of 214 patients at the cataract presurgery clinic. The parameters compared were axial length, corneal power, cylinder, and the corresponding intraocular lens power, which was calculated using the Sanders-Retzlaff-Kraff/Theoretical formula. RESULTS: This study found no statistically significant difference before and after dilation in axial length (0.005 mm; P = .476), corneal power (0.001 diopters [D]; P = .933), or calculated intraocular lens power (0.011 D; P = .609). A statistically significant difference was shown in cylinder measurements before and after dilation (0.102 D; P < .001). CONCLUSIONS: This study demonstrated there is no clinically significant effect of pupil dilation on the IOLMaster measurements of axial length, corneal power, and corresponding theoretical intraocular lens power calculated using the Sanders-Retzlaff-Kraff/Theoretical formula.

Air-pulse corneal applanation signal curve parameters for characterization of astigmatic corneas.

PURPOSE: The aim of this study was to test the 42 parameters of the ocular response analyzer for distinguishing between the biomechanical properties of emmetropic eyes with normal topography and eyes with moderate-to-high with-the-rule astigmatism (WTA) and against-the-rule astigmatism (ATA) that have symmetric bowtie topography. METHODS: This retrospective case series study included 37 patients (37 studied eyes) with WTA astigmatism and 35 patients (35 studied eyes) with ATA astigmatism. The control group consisted of 70 patients with emmetropia (70 studied eyes) with normal topography. We first tested correlations of the parameters that describe the applanation curve during ocular response analyzer measurements with the maximum keratometry values and the corneal thickness in all 3 groups. We then evaluated the significant parameters among them in search of any group differences in the biomechanical properties of the cornea. RESULTS: Fifteen parameters correlated with Kmax reading values or corneal thickness values. The correlation coefficients (r) were low. The best correlated parameters were p1area, p2area, h1, dive1, p2area1, h11, h2, and h21. The ATA group had the highest number of parameters (n = 6) with significant differences compared with the control group. Only p2area was predictive for ATA. In contrast, the WTA group had only 1 parameter (p2area1) that was found to be significantly different compared with the control group. CONCLUSIONS: Some of the new waveform parameters can distinguish between patients with ATA and WTA and normal topography patterns and may delineate the differences in biomechanical properties between these groups that may predict the risk of corneal ectasia after laser in situ keratomileusis.

[Proptosis and ophthalmoplegia after cataract surgery].

We report a case of a 57 years old female presenting with proptosis, periorbital swelling and ophthalmoplegia, 4 days after an uneventful phacoemucification surgery. Visual acuity was 20/200, biomicroscopy showed mild corneal edema and anterior chamber cells with normal posterior segment. The patient was febrile with leukocytosis and elevated Levels of C-reactive protein. A head computed tomography venography scan showed left eye proptosis, bilateral paranasal sinus hyper-density with massive sinus vein thrombosis extending from the left ophthalmic vein to the left cavernous, transversal and sigmoidal sinuses, the right cavernous and sigmoidal sinuses and internal jugular veins bilaterally. Very mild infiltration was seen around the Left ophthalmic vein, with no other signs of orbital inflammation. Emergency endoscopic sinus surgery was performed followed by anticoagulation and antibiotic treatment, blood and sinus culture later grew streptococci. The therapeutic measures resulted in complete resolution of the ocular and systemic findings.

Diameters of retinal blood vessels in a healthy cohort as measured by spectral domain optical coherence tomography.

PURPOSE: To describe a method for measuring the diameters of large retinal blood vessels by means of spectral domain optical coherence tomography. METHODS: Prospective cohort study of 29 healthy subjects (58 eyes) who underwent a spectral domain optical coherence tomography examination. Two cubes of horizontal scans were placed at the superior and inferior borders of the disk to include the large temporal retinal vessels. Vessels diameters were measured, and an artery-to-vein ratio was calculated at 10 measurement points (480-1440 µm superiorly and inferiorly from the optic disk border). RESULTS: The mean age of the study subjects was 41.45 ± 15.53 years. Patients had no ocular or systemic pathologies. The mean diameter of the retinal artery was 135.73 ± 15.64 µm and of the vein 151.32 ± 15.22 µm at the measurement point of 480 µm, with a gradual decrease to 123.01 ± 13.43 µm and 137.69 ± 13.84 µm, respectively, at 1440 µm. The artery-to-vein ratio was ≈ 0.9 at all points of measurement. CONCLUSION: This is a new noninvasive method for retinal blood vessels diameter measurement using the spectral domain optical coherence tomography imaging modality. This method may aid in evaluation of retinal and systemic vascular diseases.

Retinal toxicity of intravitreal rituximab in albino rabbits.

PURPOSE: To evaluate retinal toxicity of intravitreal rituximab. METHODS: Twelve albino rabbits were included in the study. 1 mg/0.1 mL of rituximab was injected to the right (experimental) eye of each rabbit, and 0.1 mL of saline was injected into the left (control) eye. Electroretinogram was recorded before injection and 3 hours, 4 days, 1 week, 2 weeks and 4 weeks after injection (12 rabbits), and visual evoked potential was recorded before injection and 4 weeks after injection (10 rabbits). Histology and glial fibrillary acidic protein immunocytochemistry (12 rabbits) were performed at 4 weeks after injection. Clinical examination was conducted at all time points in all rabbits. RESULTS: The average dark-adapted electroretinogram b-wave Vmax ratios, and the average light-adapted b-wave amplitude ratios were approximately 1, and the average log σ difference was around zero throughout the follow-up period. The average visual evoked potential amplitude ratio and the average visual evoked potential implicit time difference were approximately 1 and 0, respectively. No histologic damage was seen, but glial fibrillary acidic protein was mildly expressed in 6 of 12 experimental eyes. Results of clinical examination were normal in all the eyes. CONCLUSION: Intravitreal injection of 1 mg rituximab does not cause functional or histologic signs of retinal toxicity in albino rabbits. Mild glial fibrillary acidic protein expression in Müller cells probably indicates a mild degree of retinal stress.

Physiological and toxicological effects of cefuroxime on the albino rabbit retina.

PURPOSE: Intracameral cefuroxime was found to lower the risk of endophthalmitis after cataract surgery. The purpose of this study was to evaluate the retinal toxicity of cefuroxime in a rabbit model. METHODS: Twenty-two albino rabbits were divided into two cefuroxime groups: low-dose (1mg/0.1 mL, n = 9) and high dose (10 mg/0.1 mL, n = 13). The right eye of each rabbit was injected with 0.1 mL cefuroxime solution (experimental eye) and the left eye with 0.1 mL saline (control eye). Electroretinogram (ERG) responses were recorded at 3 hours, 4 days, and 1, 2, and 4 weeks after injection. After 4 weeks, the rabbits were euthanized, the eyes were enucleated, and the retinas were prepared for histologic evaluation and GFAP immunostaining. RESULTS: No functional (ERG) or histologic damage was found in rabbits in the low-dose group. In the high-dose group, a significant decrease in the ERG amplitudes of the experimental eyes was seen 3 hours after injection, followed by partial recovery during 4 weeks of follow-up. Retinal histology of experimental eyes revealed marked damage. GFAP immunoreactivity in Müller cells was expressed in rabbits belonging to both groups, although it was more extensive in the high-dose group. CONCLUSIONS: ERG and histologic findings indicated that a dose of 1 mg cefuroxime, administered intravitreally, was not toxic to the rabbit retina. A dose of 10 mg, injected intravitreally, induced transient physiological effects, and was toxic to the rabbit retina, as was evident by the permanent reduction in the ERG responses and by the structural damage to the retina with signs of glial activation.

Electrophysiologic and retinal penetration studies following intravitreal injection of bevacizumab (Avastin).

PURPOSE: Intravitreal bevacizumab (Avastin; Genentech Inc., San Francisco, CA) is a new treatment for age-related macular degeneration. The aim of this study was to evaluate retinal penetration and toxicity of bevacizumab. METHODS: Ten albino rabbits were injected intravitreally with 0.1 mL (2.5 mg) of Avastin into one eye and 0.1 mL saline into the fellow eye. The electroretinogram (ERG) was recorded after 3 hours, 3 days, and 1, 2, and 4 weeks. The visual evoked potential (VEP) was recorded after 4 weeks. Confocal immunohistochemistry was used to assess retinal penetration. RESULTS: The ERG responses of the control and experimental eyes were similar in amplitude and pattern throughout the follow-up period. The flash VEP responses of the experimental eyes were of normal pattern and amplitude and did not differ from those recorded by stimulation of the control eye alone. Full thickness retinal penetration was present at 24 hours and was essentially absent at 4 weeks. CONCLUSIONS: Bevacizumab was found to be nontoxic to the retina of rabbits based on electrophysiologic studies. Full thickness retinal penetration may explain observed clinical effects of intravitreal bevacizumab. Although it is difficult to directly extrapolate to humans, our study supports the safe use of intravitreal bevacizumab injection.