Optic nerve morphology in normal children.

PURPOSE: To expand the normative database of pediatric eyes analyzed with the Optovue optical coherence tomography (OCT). METHODS: In a community-based, cross-sectional analysis, 77 healthy 5-year-old children were recruited from pediatric practices. No subject had any known ocular disorder. Their optic nerves were assessed using Optovue optical coherence tomography (OCT). Data were compared to the normative database obtained by Optovue for adults, ages 18-25, 40-45, and 55-60. Comparisons included thickness of retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC), and optic nerve head disk area, vertical (VCD) and horizontal (HCD) cup:disk ratios, and cup area. RESULTS: In comparison to all adult age groups, the children's optic nerve heads were statistically less cupped (cup area, VCD, HCD), all with P values of <0.0003. No statistical difference was identified between the children and adults aged 18-25 and 40-45 with respect to RNFL or GCC. Both RNFL and GCC were thicker in the children compared to adults aged 55-60 (P < 0.003). Children's disk area's were marginally smaller than those of adults, the difference not reaching statistical significance. CONCLUSIONS: Our OCT results demonstrate that young children's optic nerves are statistically less cupped than those of all normal adults. The children's RNFL and GCC are statistically thicker than those of adults aged 55-60.

Anterior chamber gas bubble emergence pattern during femtosecond LASIK-flap creation.

AIM: To characterise the emergence pattern of cavitation bubbles into the anterior chamber (AC) following femtosecond laser-assisted in situ keratomileusis (LASIK)-flap creation METHODS: Retrospective review of patients undergoing femtosecond LASIK surgery at Boston Laser, a private refractive surgery practice in Boston, Massachusetts, between December 2008 and February 2014. Patient charts were reviewed to identify all cases with gas bubble migration into the AC. Surgical videos were examined and the location of bubble entry was recorded separately for right and left eyes. RESULTS: Five thousand one hundred and fifty-eight patients underwent femtosecond LASIK surgery. Air bubble migration into the AC, presumably via the Schlemm's canal and trabecular meshwork, occurred in 1% of cases. Patients with AC bubbles had an average age of 33±8 years with a measured LASIK flap thickness of 96±21 µm. The occurrence of gas bubbles impaired iris registration in 64% of cases. Gas bubbles appeared preferentially in the nasal or inferior quadrants for right (92% of cases) and left (100% of cases) eyes. This bubble emergence pattern is significantly different from that expected with a random distribution (p<0.0001) and did not seem associated with decentration of the femtosecond laser docking system. CONCLUSIONS: The migration of gas bubbles into the AC is a rare occurrence during femtosecond laser flap creation. The preferential emergence of gas bubbles into the nasal and inferior quadrants of the AC may indicate a distinctive anatomy of the nasal Schlemm's canal.

An implantable intraocular pressure transducer: initial safety outcomes.

IMPORTANCE: To our knowledge, this is a report of the first implantation of a wireless intraocular pressure transducer (WIT) in a human eye. OBJECTIVE: To report preliminary safety data on the WIT. DESIGN, SETTING, AND PARTICIPANT: In an institutional setting, a patient with open-angle glaucoma consented to be the recipient of the WIT in one eye in an interventional study design. INTERVENTIONS: The WIT was implanted into the ciliary sulcus following extracapsular cataract extraction and "in the bag" intraocular lens implantation. The patient was monitored postoperatively for 18 months. MAIN OUTCOMES AND MEASURES: Any adverse events. RESULTS: There were no complications noted during the WIT insertion or postoperatively. No persistent intraocular inflammation, pigment dispersion, or angle narrowing was noted. CONCLUSIONS AND RELEVANCE: The WIT was well tolerated in the eye and no overt signs of toxicity or other adverse events were noted. This may allow the constant monitoring of intraocular pressure in the future.

Retention of the Boston keratoprosthesis type 1: multicenter study results.

OBJECTIVE: To report the retention rate of the Boston keratoprosthesis type 1 and to identify risk factors for keratoprosthesis loss. DESIGN: Cohort study. PARTICIPANTS: A total of 300 eyes of 300 patients who underwent implantation of the Boston keratoprosthesis type I device between January 2003 and July 2008 by 19 surgeons at 18 medical centers. METHODS: Forms reporting preoperative, intraoperative, and postoperative parameters were prospectively collected and subsequently analyzed at a central data collection site. MAIN OUTCOME MEASURES: Keratoprosthesis retention. RESULTS: A total cumulative number of 422 life-years of device implantation are included in this analysis. The average duration of follow-up was 17.1 ± 14.8 months, with a range of 1 week to >6.1 years. Ninety-three percent of the 300 Boston keratoprosthesis implants were retained at their last follow-up, corresponding to a retention time of 396 patient-years or 1.42 years/keratoprosthesis. The probability of retention after 1 year and 2 years was 94% and 89%, respectively. During the study period, 21 (7%) eyes failed to retain the device; the reasons for keratoprosthesis loss include sterile keratolysis (9), fungal infections (8), dense retroprosthetic membranes (3), and bacterial endophthalmitis (1). Multivariate analysis demonstrated 3 independent risk factors for keratoprosthesis loss: autoimmune cause (hazard ratio [HR], 11.94; 95% confidence interval [CI], 3.31-43.11), ocular surface exposure requiring a concomitant tarsorrhaphy (HR, 3.43; 95% CI, 1.05-11.22), and number of prior failed penetrating keratoplasties (HR, 1.64; 95% CI, 1.18-2.28). CONCLUSIONS: The Boston keratoprosthesis type 1 seems to be a viable option for eyes that are not candidates for penetrating keratoplasty (PK). Ocular surface disease due to an autoimmune cause demonstrated the lowest retention rate. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Risk factors for the development of retroprosthetic membranes with Boston keratoprosthesis type 1: multicenter study results.

OBJECTIVE: The purpose of this study was to identify possible risk factors for retroprosthetic membrane (RPM) development in a large, multicenter cohort of patients receiving a Boston type 1 keratoprosthesis. DESIGN: Cohort study. PARTICIPANTS: The final analysis included 265 eyes of 265 patients who underwent implantation of a Boston keratoprosthesis type I device between January 2003 and July 2008 by 1 of 19 surgeons at 18 medical centers. METHODS: Forms reporting preoperative, intraoperative, and postoperative parameters were prospectively collected and subsequently analyzed at a central data collection site. MAIN OUTCOME MEASURES: The primary outcome was the presence or absence of an RPM during the follow-up period. RESULTS: The average age of patients was 63.3±19.1 years, 48.5% of the patients were female, and 52.5% of procedures were performed on the right eye. The mean follow-up time was 17.8±14.9 months. The majority (85.4%; n = 222) had undergone an average of 2.2±1.2 (range, 1-8) penetrating keratoplasties before keratoprosthesis implantation, and 38 eyes (14.6%) received a primary keratoprosthesis. The overall RPM formation rate was 31.7% (n = 84). The most significant risk factor for RPM development was infectious keratitis (as a surgical indication for keratoprosthesis surgery itself), resulting in a rate of RPM formation of 70.6%. As an independent risk factor, the hazard ratio (HR) of RPM development in these eyes was 3.20 (95% confidence interval, 1.66-6.17). Aniridia was also an independent risk factor for RPM development (HR, 3.13; 95% confidence interval, 1.10-8.89). CONCLUSIONS: Formation of RPM is a common complication of keratoprosthesis surgery, occurring in approximately one-third of cases. Eyes at the highest risk of RPM development are those receiving corneal replacement for infectious keratitis and aniridia.

Intraocular pressure measurement by radio wave telemetry.

PURPOSE: To determine the biocompatibility of a new wireless intraocular pressure (IOP) transducer (WIT) in rabbit eyes and to correlate its measurements with other pressure-measuring devices. METHODS: The WIT is a ring-shaped intraocular device that allows wireless IOP measurements through radiofrequency. It was implanted into six eyes of New Zealand White rabbits after extracapsular lens extraction. A sham rabbit eye with no transducer implanted was used as a control. The animals were observed and examined by microscopy at various intervals up to 25 months after surgery. IOP was measured at various intervals by pneumotonometry, tonometry, WIT, and manometry. The data from the various devices were compared and analyzed for reproducibility. Two eyes were enucleated at 5.5 and 20 months after implantation and analyzed by histology. RESULTS: The WIT appears to be well tolerated in the rabbit eye, with no evidence of significant inflammation or scar formation by microscopic in vivo examination. Histology did not reveal intraocular inflammation or membrane formation. Repeated IOP measurements with pneumotonometry, tonometry, and the WIT resulted in SDs of 2.70 mm Hg, 3.35 mm Hg, and 0.81 mm Hg, respectively. The concordance between the WIT and direct manometry measurements was high. A downward drift in IOP measured by the WIT was noted in three rabbits, necessitating recalibration. CONCLUSIONS: The WIT is well tolerated by the rabbit eye. Its measurements are reproducible and in close concordance with manometry. A downward IOP drift warrants further investigation.

Prevention of visually debilitating deposits on soft contact lenses in keratoprosthesis patients.

PURPOSE: To describe visually debilitating deposit formation on hydrogel contact lenses routinely used for protection in eyes with keratoprosthesis and to present different types of contact lenses that provide improved deposit resistance. METHODS: Seven keratoprosthesis eyes with a history of rapid and severe deposit formation on their hydrogel lenses were evaluated and documented. The Schirmer values and blink rate of each patient were additionally analyzed. These patients were then subsequently refitted with varying types of contact lenses. RESULTS: When soft hydrogel lenses were replaced with lenses with water-impermeable centers, dramatically fewer deposits accumulated. Deposit formation on hydrogel lenses did not seem to correlate with low Schirmer values but rather with an insufficient blink rate. CONCLUSION: Excellent deposit resistance can be achieved in these patients with the use of hybrid contact lenses with rigid centers or large-diameter entirely rigid contact lenses.

Biocompatibility and biofilm inhibition of N,N-hexyl,methyl-polyethylenimine bonded to Boston Keratoprosthesis materials.

The biocompatibility and antibacterial properties of N,N-hexyl,methyl-polyethylenimine (HMPEI) covalently attached to the Boston Keratoprosthesis (B-KPro) materials was evaluated. By means of confocal and electron microscopies, we observed that HMPEI-derivatized materials exert an inhibitory effect on biofilm formation by Staphylococcus aureus clinical isolates, as compared to the parent poly(methyl methacrylate) (PMMA) and titanium. There was no additional corneal epithelial cell cytotoxicity of HMPEI-coated PMMA compared to that of control PMMA in tissue cultures in vitro. Likewise, no toxicity or adverse reactivity was detected with HMPEI-derivatized PMMA or titanium compared to those of the control materials after intrastromal or anterior chamber implantation in rabbits in vivo.

Titanium back plate for a PMMA keratoprosthesis: clinical outcomes.

BACKGROUND/PURPOSE: To compare the rate of retroprosthetic membrane (RPM) formation in Boston Keratoprosthesis (BKPro) with polymethyl methacrylate (PMMA) versus titanium backplates. DESIGN: Retrospective comparative chart review. METHODS: Multicenter study population: a total of 78 eyes with keratoprosthesis implants with either PMMA or titanium backplates were included in the study. To be included in the study, all subjects had to have completed a minimum of 6-month follow-up period. Incidence of RPM development at 6-month postoperative period was noted across the study population. PMMA and titanium backplates were then compared by their rate of association with subsequent RPM. RESULTS: Twenty-three out of 55 eyes (41.8%) with PMMA backplates and three out of 23 eyes (13.0%) with titanium backplates had developed an RPM at 6 months after implantation. The titanium backplates were associated with significantly less RPM formation than PMMA backplates (p = 0.014, Chi-square test). CONCLUSIONS: Titanium seems to be associated with less RPM formation than PMMA when used as a material for the BKPro back plate.

Repositioning free laser in situ keratomileusis flaps.

We describe a protocol for adequate repositioning of free laser in situ keratomileusis (LASIK) corneal flaps created by a Moria M2 microkeratome even in the absence of fiduciary marks. In an enucleated porcine globe, a free flap was created by initially placing a longitudinal incision at the proposed hinge site followed by activating the forward pass of the automated microkeratome. A protocol was devised based on placement of a positioning dot on the free flap before the flap is retrieved from the microkeratome head. Preplaced surgical landmarks were used as a guide to determine the correct alignment of the free flap. Adequate orientation of the free flap to the stromal bed was achieved in 9 porcine eyes using the positioning dot method. The technique is applicable to the Moria M2 microkeratome only and must be validated for other types of keratomes.

Cost-effectiveness of the Boston keratoprosthesis.

PURPOSE: To conduct a cost-utility analysis and determine the cost-effectiveness of the Boston Keratoprosthesis (Boston Kpro). DESIGN: Retrospective cohort study. METHODS: setting: The Massachusetts Eye and Ear Infirmary corneal service. patients: Inclusion required a minimum 2-year follow-up. Patients with autoimmune diseases and chemical burns were excluded. Eighty-two patients were included with various indications for surgery. intervention: The keratoprosthesis is a collar button-shaped polymethylmethacrylate (PMMA) device consisting of 2 curved plates sandwiched around a corneal donor (allo)graft. The device is assembled intraoperatively and sutured to a patient's eye after removing the diseased cornea. MAIN OUTCOME MEASURES: Average cost-effectiveness of the keratoprosthesis was determined by cost-utility analysis, using expected-value calculations and time-tradeoff utilities. The comparative effectiveness, or gain in quality-adjusted life years (QALYs), was also sought. Cost-effectiveness was compared to recently published data on penetrating keratoplasty (PK). RESULTS: A total discounted incremental QALY gain for the Boston Kpro of 0.763 correlated with a conferred QALY gain of 20.3% for the average patient. The average cost-effectiveness of the keratoprosthesis was $16 140 per QALY. CONCLUSIONS: Comparable to corneal transplantation, with a cost-effectiveness between $12 000 and $16 000 per QALY, the keratoprosthesis can be considered highly cost-effective.

Late-onset epithelial ingrowth after laser in situ keratomileusis.

We report a case of late-onset epithelial ingrowth that occurred between 17 months and 20 months after an uneventful laser in situ keratomileusis (LASIK) enhancement. The patient denied a history of trauma or symptoms consistent with epithelial disruption. Post-LASIK treatment had included lifting the flap and scraping the epithelial cells followed by placement of corneal flap sutures for several weeks and a bandage contact lens for 3 days. Gradual regression of epithelial cells was noted. The last recorded uncorrected distance visual acuity 24 months after scraping was 20/25. Epithelial ingrowth can occur many months after LASIK even in the absence of predisposing factors such as trauma or recurrent erosion syndrome.

Laser in situ keratomileusis buttonhole: classification and management algorithm.

PURPOSE: To report the classification, management, and visual outcomes after laser in situ keratomileusis (LASIK) flap buttonhole caused by a microkeratome cut. SETTING: Private practice, Boston, Massachusetts, USA. METHODS: This retrospective observational case series comprised 15 patients with an intraoperative LASIK flap buttonhole or near buttonhole. In all cases, the flap was left in place or repositioned without excimer laser treatment. Buttonholes were classified by stage, and a treatment algorithm based on the stage was devised to determine the timing and type of intervention. The uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and complications associated with the laser vision correction surgery were reported. RESULTS: Postoperative follow-up ranged from 1 week to 23 months. All 9 patients who were retreated had a postoperative UCVA of 20/25 or better. No retreated patient lost BSCVA. Before retreatment, the median UCVA was 20/80 (range 20/40(-1) to counting fingers), the median BSCVA was 20/20(-2) (range 20/15(-1) to 20/70), and the spherical equivalent (SE) refractive errors ranged from -1.00 to -6.62 diopters (D). After retreatment, the median UCVA was 20/20(-2) (range 20/15(-1) to 20/25(-1)), the median BSCVA was 20/20 (range 20/15 to 20/20(-3)), and the SE refractive errors ranged from +0.50 to -0.75 D. Complications after laser correction treatment included overcorrection in 3 patients and corneal haze in 2 patients. CONCLUSIONS: Classification of buttonholes was helpful in guiding treatment. Good UCVA and BSCVA were achieved by following a simple treatment algorithm based on surface ablation.

Persistent conjunctivitis associated with drinking arsenic-contaminated water.

PURPOSE: The aim of this study was to report on 2 cases of bilateral chronic conjunctivitis that were associated with the drinking of arsenic-contaminated underground water for a long time. DESIGN: Interventional case reports comprised the study. METHODS: This study was a review of clinical data and laboratory investigations. RESULTS: Papillary conjunctivitis developed in 2 members of a family who has been drinking underground water for 15 years. There were severe dermatological changes, including hyperkeratosis, on palms and soles, hypo- and hyperpigmented lesions (rain-drop) on the abdomen, chest, and back. Arsenic levels estimated in the nails and hair of both patients were very high. The arsenic level of the drinking water was above the permissible limit. Histopathological examination of conjunctival tissue confirmed the inflammatory response of a papillary type; however, an arsenic estimation in conjunctival tissue was not possible. There were no inclusions of bodies in conjunctival smears stained with hematoxylin and eosin (H&E) stain. There was no response to the usual treatment for papillary conjunctivitis, which only subsided, along with a regression of dermatological changes, when patients were treated with the chelating agent, dimercaprol, and multivitamin preparations, as well as no longer drinking the contaminated water. CONCLUSIONS: This is a rare association and, to the best of our knowledge, the first report of successful treatment with dimercarpol. The source of arsenic was contaminated underground drinking water (from a deep tube-well). The pathophysiology is thought to be the result of an inflammatory response caused by accumulated arsenic in local tissues. Papillary conjunctivitis and dermatological changes can be successfully managed with dimercaprol and multivitamins. Further studies are required to find out the possible link between the papillary response of conjunctiva and arsenic accumulation within the body.

Hurler's disease.

Hurler's disease, also known as mucopolysaccharidoses 1H, an autosomal recessive disease due to enzyme alpha-iduronidase deficiency has generally a spectrum of findings involving the eye, skeletal abnormality, organomegaly, joint stiffness, hernia, mental retardation and cardiovascular abnormalities. The two cases presented here are related to each other as brother of 9 years age and sister of 7 years of age with their parents had consanguineous marriage. On ocular examination in both the cases there was dense bilateral corneal opacities. Glycosaminoglycan's level was found to be 4 mg/mmol cr in the first case and 5 mg/mmol cr in the second case. In the first case no ocular treatment was planned and in the second case penetrating keratoplasty was the choice of management.