Yaron Lang

Intraocular pressure and photorefractive keratectomy: A comparison of three different tonometers

Purpose. To evaluate the intraocular pressure (IOP) with three different instruments, Goldmann applanation tonometer (GAT), noncontact tonometer, and Tono-Pen after photorefractive keratectomy (PRK) for myopia. Methods. A prospective case series study to evaluate preoperative and postoperative IOP measurements of 149 eyes at 12 months. We performed GAT, noncontact tonometry, Tono-Pen central, and Tono-Pen temporal periphery measurements. We also performed measurements of the central corneal thickness (CCT) by ultrasonic pachymetry and keratometry. Preoperative IOP reading served as control for all studies. Results. After PRK, IOP reading was significantly reduced in the treated eyes when compared with the control measurements (11.87 ± 1.73 vs. 13.37 ± 1.52 mmHg, p < 0.0001 with GAT; 12.07 ± 1.6 vs. 13.51 ± 1.59 mmHg, p < 0.0001 with noncontact tonometer; 12.18 ± 1.6 vs. 13.48 ± 1.55 mmHg, p < 0.0001 with Tono-Pen central; 13.48 ± 1.65 vs. 13.71 ± 1.56 Hg, p < 0.0104 with Tono-Pen temporal periphery). There was also a significant correlation between IOP reading changes measured by GAT, noncontact tonometer, Tono-Pen central, and change of CCT and between reduction of IOP reading and keratometry (r2> 0.39, p < 0.0001 for each). The correlation between IOP reading change by Tono-Pen temporal periphery and CCT was also significant but r2value was only 0.034. Tono-Pen temporal periphery postoperative IOP measurements had the best correlation with preoperative GAT IOP (r2= 0.57, p < 0.0001). Conclusions. PRK reduced IOP reading as measured by GAT, noncontact tonometer, and Tono-Pen central; less so when measured by Tono-Pen temporal periphery. Early detection of glaucoma and IOP follow-up in glaucoma patients may be done best by peripheral Tono-Pen measurements over the nonablated cornea.

Preoperative topical moxifloxacin 0.5% and povidone-iodine 5.0% versus povidone-iodine 5.0% alone to reduce bacterial colonization in the conjunctival sac

PURPOSE: To assess the effectiveness of adding topical moxifloxacin 0.5% to topical povidone–iodine 5.0% for preoperative reduction of bacterial recovery from the conjunctiva. SETTING: Emek Medical Center, Afula, Israel. METHODS: The study population comprised adult patients scheduled for elective intraocular surgery. Two hours before surgery, patients were randomly assigned to topical therapy with moxifloxacin 0.5% drops (study group) or normal saline drops (control group). Povidone–iodine 5% solution was also instilled in the conjunctival sac in both groups for 3 minutes immediately before surgery. Conjunctival cultures were obtained before prophylactic therapy and just before surgery. The major outcome measures were the rate of bacterial colonization and bacterial type in conjunctival cultures obtained after instillation of povidone–iodine and immediately before surgery. RESULTS: Overall, 464 patients completed the study; there were 237 patients in the study group and 227 patients in the control group. Positive conjunctival cultures were obtained before prophylactic therapy in 91 patients (38%) in the study group and 94 patients (41%) in the control group and just before surgery in 10 patients (4%) and 6 patients (3%), respectively; neither difference was statistically significant. Coagulase‐negative Staphylococcus was the most prevalent bacteria and was found equally in both groups. CONCLUSIONS: Treatment with povidone–iodine 5.0% alone was effective in preoperative reduction of conjunctival bacterial colonization. Adding topical moxifloxacin 0.5% to povidone–iodine 5.0% had no significant effect on further reduction in the bacterial colonization rate.

Retinal toxicity of intravitreal kenalog in albino rabbits.

Purpose: To evaluate possible toxicity of intravitreal Kenalog (commercial triamcinolone acetonide) to the retina of albino rabbits. Methods: Forty-three albino rabbits were injected intravitreally with 0.1 mL of experimental solution to the right eye and 0.1 mL of saline to the left eye (control). Rabbits in Group A (n = 28) were injected with 4 mg/0.1 mL of Kenalog suspension; rabbits in Group B (n = 8) were injected with 0.1 mL of Kenalog vehicle; and rabbits in Group C (n = 7) were injected with 4 mg/0.1 mL of triamcinolone acetonide. Rabbits were examined ophthalmoscopically and by electroretinogram (ERG) recordings before and at different time intervals after injection. At the end of follow-up, animals were killed and the retinas were prepared for light microscopy. Results: Thirty-eight rabbits completed 4 weeks of follow-up. Follow-up for 8 and 17 weeks was completed by 29 and 3 rabbits, respectively. Intravitreal commercial Kenalog or its vehicle alone caused approximately 50% reduction in the ERG b-wave amplitude at the end of follow-up. Pure triamcinolone acetonide caused only mild (up to 14%) reduction of the ERG b-wave amplitude. Histologic examination of retinas exposed to Kenalog or its vehicle showed severe damage to all retinal layers in areas close to the site of Kenalog injection. Conclusions: Intravitreal injection of 4 mg Kenalog suspension is retinotoxic to albino rabbit eyes. The vehicle of Kenalog is probably the main cause of this toxicity.

Toward earlier detection of choroidal neovascularization secondary to age-related macular degeneration: multicenter evaluation of a preferential hyperacuity perimeter designed as a home device.

Purpose: The primary purpose of this study was to evaluate the ability of a home device preferential hyperacuity perimeter to discriminate between patients with choroidal neovascularization (CNV) and intermediate age-related macular degeneration (AMD), and the secondary purpose was to investigate the dependence of sensitivity on lesion characteristics. Methods: All participants were tested with the home device in an unsupervised mode. The first part of this work was retrospective using tests performed by patients with intermediate AMD and newly diagnosed CNV. In the second part, the classifier was prospectively challenged with tests performed by patients with intermediate AMD and newly diagnosed CNV. The dependence of sensitivity on lesion characteristics was estimated with tests performed by patients with CNV of both parts. Results: In 66 eyes with CNV and 65 eyes with intermediate AMD, both sensitivity and specificity were 0.85. In the retrospective part (34 CNV and 43 intermediate AMD), sensitivity and specificity were 0.85 ± 0.12 (95% confidence interval) and 0.84 ± 0.11 (95% confidence interval), respectively. In the prospective part (32 CNV and 22 intermediate AMD), sensitivity and specificity were 0.84 ± 0.13 (95% confidence interval) and 0.86 ± 0.14 (95% confidence interval), respectively. Chi-square analysis showed no dependence of sensitivity on type (P = 0.44), location (P = 0.243), or size (P = 0.73) of the CNV lesions. Conclusion: A home device preferential hyperacuity perimeter has good sensitivity and specificity in discriminating between patients with newly diagnosed CNV and intermediate AMD. Sensitivity is not dependent on lesion characteristics.

Vitrectomy to remove a posteriorly dislocated endocapsular tension ring

We treated a patient who had a posteriorly dislocated endocapsular ring associated with decreased vision and intravitreal cortical remnants. The ring was removed by uneventful pars plana vitrectomy. By the last examination, best corrected visual acuity had improved to 6/12 and intraocular pressure had stabilized to within normal limits. A posteriorly dislocated endocapsular ring is a rare complication of cataract surgery. Its removal by pars plana vitrectomy under direct observation is effective and safe.

Intraocular pentastomiasis causing unilateral glaucoma.

We present a case of intraocular pentastomiasis in a 12-year-old Israel Arab boy. A single secondary pentastomid larva, most likely of Linguatula serrata, was found in the anterior chamber of the right eye, attached loosely to the pupils border by a fibrinous mass. Associated conditions were iritis, subluxation of the lens, and secondary glaucoma. This is the first documentation of human pentastomiasis in Israel.

Cone-rod dysfunction in patients with unexplained reduction in visual acuity.

Electrophysiologic tests were performed in 233 patients who complained of reduced visual acuity with no satisfactory clinical explanation. The functional integrity of the retina was assessed from the light-and dark-adapted electroretinogram., Macular function and conduction in the optic nerves were estimated from the flash visual evoked potentials. Of the 233 patients 78 were grouped together on the basis of the electrophysiologic and clinical findings. They were characterized by subnormal electroretinogram responses with the cone system more affected than the rod system. The flash visual evoked potential responses were of abnormal waveform and prolonged implicit times. Most of these patients exhibited normal fundi. The reduction in visual acuity, the degree of electroretinogram deficits and the pattern of the visual evoked potential responses were similar in both eyes of each, patient, indicating a symmetric disorder. Slight deterioration of visual acuity and electrophysiologic variables were observed in 37 of the patients who were followed up over a period of up to 8 years. The electrophysiologic findings indicate that about 20% of patients complaining of unexplained reduction in visual acuity were suffering from a diffuse retinal disorder affecting the peripheral retina as well as the macular region. On the basis of electrophysiologic findings and clinical symptoms, we suggest grouping these patients under a new entity: cone-rod dysfunction.

Traumatic Central Retinal Artery Occlusion

A healthy 6-year-old boy with a clinical picture of central retinal artery occlusion (CRAO) of his left eye is presented here. The underlying cause was a trauma to the boys left cheek some 6 months earlier. Possible pathophysiological mechanisms are discussed. To the best of our knowledge, the late onset of traumatic CRAO has not yet been reported in the literature.

A Perforating Eye Injury Caused by a Staple Gun, Treated Successfully Without Vitrectomy

A 30-year-old carpenter accidentally impaled his own left eye with a 5 cm staple ejected from a pneumatic gun. Entering the globe off-axis, the stainless steel staple caused a vitreous hemorrhage. On the day of injury, the staple was removed surgically. The vitreous hemorrhage cleared rapidly enough to permit laser treatment around the equatorial retinal perforation site. Visual acuity improved to 6/9 and remained stable over a one-year period of careful follow-up. No retinal detachment developed. No additional intervention was required. While vitrectomy with or without a circular buckling remains the standard for perforations into the posterior segment, selected cases may be managed conservatively.