Endoscopic endonasal decompression of the optic nerve in the setting of compressive lesions: how I do it

BACKGROUND

Many lesions in the anterior skull base may compress the optic nerve (ON), leading to vision loss, and even irreversible blindness. Although decompression of the optic nerve has traditionally been achieved transcranially, the endoscopic endonasal approach (EEA) is gaining traction as a minimally invasive approach recently.

METHOD

We describe the key steps of an EEA ON decompression. The relevant surgical anatomy with illustration is described. Additionally, a video detailing our technique and instruments on an illustrative case is provided.

CONCLUSION

Endoscopic endonasal approach ON decompression with a straight feather blade is a feasible, minimally invasive procedure to decompress the ON in the setting of anterior skull base mass lesions.

Minimally Invasive Bleb Surgery for Glaucoma: A Health Technology Assessment

Background

Glaucoma is the term for a group of eye disorders that causes progressive damage to the optic nerve, which can lead to visual impairment and, potentially, irreversible blindness. Minimally invasive bleb surgery (MIBS) reduces eye pressure through the implantation of a device that creates a new subconjunctival outflow pathway for eye fluid drainage. MIBS is a less invasive alternative to conventional/incisional glaucoma surgery (e.g., trabeculectomy). We conducted a health technology assessment of MIBS for people with glaucoma, which included an evaluation of effectiveness, safety, the budget impact of publicly funding MIBS, and patient preferences and values.

Methods

We performed a systematic literature search of the clinical evidence. We assessed the risk of bias of each included study using the Cochrane Risk of Bias 1.0 tool for randomized controlled trials (RCTs) and the Risk of Bias Assessment tool for Nonrandomized Studies (RoBANS) for comparative observational studies, and the quality of the body of evidence according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group criteria. We conducted an economic literature search and we estimated the budget impact of publicly funding MIBS in Ontario. We did not conduct a primary economic evaluation due to the limited long-term effectiveness data. We summarized the preferences and values evidence from previous health technology assessments to understand the perspectives and experiences of patients with glaucoma.

Results

We included 41 studies (2 RCTs and 39 comparative observational studies) in the clinical evidence review. MIBS may reduce intraocular pressure and the number of medications used, but we are uncertain if MIBS results in outcomes similar to trabeculectomy (GRADE: Moderate to Very low). Compared with trabeculectomy, MIBS may result in fewer follow-up visits and interventions, and adverse events (GRADE: Moderate to Very Low). MIBS may also reduce intraocular pressure and the number of antiglaucoma medications used, compared with other glaucoma treatments, but the evidence is uncertain (GRADE: Very low). Our economic evidence review identified two directly applicable studies. The results of these studies indicate that the cost-effectiveness of MIBS is highly uncertain, and the cost of glaucoma interventions are likely to vary across provinces. The annual budget impact of publicly funding MIBS in Ontario ranged from $0.11 million in year 1 to $0.67 million in year 5, for a total 5-year budget impact estimate of $1.93 million. Preferences and values evidence suggests that fear of ultimate blindness and difficulty managing medication for glaucoma led patients to explore other treatment options such as MIBS. Glaucoma patients found minimally invasive glaucoma surgery (MIGS) procedure beneficial, with minimal side effects and recovery time.

Conclusions

Minimally invasive bleb surgery reduces intraocular eye pressure and the number of antiglaucoma medications needed, but we are uncertain if the outcomes are similar to trabeculectomy (GRADE: Moderate to Very low). However, MIBS may be safer than trabeculectomy (GRADE: Moderate to Very low) and result in fewer follow-ups (GRADE: Moderate to Very low). MIBS may also improve glaucoma symptoms compared with other glaucoma treatments, but the evidence is very uncertain (GRADE: Very low).We estimate that publicly funding MIBS would result in an additional cost of $1.93 million over 5 years. Patients who underwent MIGS procedures found them to be generally successful and beneficial, with minimal side effects and recovery time. We could not draw conclusions about specific MIBS procedures or long-term outcomes.

Pediatric Corneal Transplantation in Uyo, Nigeria: Early Experiences

ABSTRACT

The burden of avoidable blindness from corneal disease is significantly higher where access to specialist eye care, the cost of treatment and the treatment infrastructure including eye banking, are beyond the reach of the impoverished masses. Corneal transplantation in children is challenging: it is more technically complex; patients often require multiple examinations under general anaesthesia to optimize treatment outcomes. There is also the increased risk of several complications including graft dehiscence, infection, rejection, and inappropriate patient or caregiver care. However, when successful, it restores vision. We present a report of our initial experience with penetrating keratoplasty in 2 children with blinding corneal disease in Uyo, Nigeria. Corneal transplantation history was retrieved and data (including data on age, sex, aetiology of corneal disease, indications for corneal transplantation, pre-operative and post-operative visual acuity and intraocular pressure measurements) was extracted for this report. Both patients had standard penetrating keratoplasty performed by one surgeon, under general anaesthesia. Case one was a 10-year-old male presenting with profound visual impairment from congenital hereditary endothelial dystrophy. His best corrected post-operative visual acuity was 6/24. Case two was a 3-year-old male with vision loss due to a corneal leucoma following treated herpes simplex keratitis. Post-operatively, his best corrected visual acuity improved to 6/12. Corneal graft tissue remained clear at more than 3 years of follow-up. Although amblyopia was a notable co-morbidity, corneal transplantation significantly improved their vision. Corneal banking services are advocated for in resource-limited settings where the magnitude of corneal blindness is greatest.

Indications and types of keratoplasties: Trends in the past 10 years (2011-2020) in Eastern India

Purpose

To observe the trends of various types of keratoplasties in different etiologies over a period of 10 years (2011-2020) in a tertiary eye care center of eastern India.

Methods

A retrospective review of patients undergoing keratoplasties from 2011 to 2020 was performed in a tertiary eye care hospital situated in eastern part of India. Apart from demographic data, primary indication for each surgery and type of procedure carried out was recorded. For comparison, data were divided into two time periods: Group I: Jan 2011 to Dec 2015 and Group II: Jan 2016 to Dec 2020.

Results

Over a period of 10 years, a total of 2365 (Group I: 902, Group II: 1463) keratoplasties were performed. The average age of patients was 45.8 ± 19.9 and 46.9 ± 20.9 years in Group I and Group II, respectively. Among all the corneal grafts, 1747 (74%) surgeries were full-thickness. Although optical penetrating keratoplasty (OPK) was most the common indication for full-thickness keratoplasties, Descemet's stripping endothelial keratoplasty (DSEK) remained most performed lamellar keratoplasty. Keratitis, corneal scars, and bullous keratopathies remain to be most common indications in both groups. Number of lamellar keratoplasties increased significantly from Group I to Group II for corneal scars (P = 0.02), bullous keratopathies (P = 0.01), and endothelial dystrophies (P = 0.00).

Conclusion

With change in time, the indication and technique of keratoplasty has witnessed a changing trend from full-thickness keratoplasty to lamellar keratoplasty. There is rise in trend of lamellar keratoplasties over the period.

Keratoprosthesis in dry eye disease

Bilateral corneal blindness with severe dry eye disease (DED), total limbal stem cell deficiency with underlying corneal stromal scarring and vascularization, combined with adnexal complications secondary to chronic cicatrizing conjunctivitis is a highly complex situation to treat. In such eyes, procedures such as penetrating keratoplasty alone or combined with limbal stem cell transplantation are doomed to fail. In these eyes, keratoprosthesis (Kpro) or an artificial cornea is the most viable option, eliminating corneal blindness even in eyes with autoimmune disorders such as Stevens-Johnson syndrome, ocular mucous membrane pemphigoid, Sjogren's syndrome, and nonautoimmune disorders such as chemical/thermal ocular burns, all of which are complex pathologies. Performing a Kpro in these eyes also eliminates the need for systemic immunosuppression and may provide relatively early visual recovery. In such eyes, the donor cornea around the central cylinder of the Kpro needs to be covered with a second layer of protection to avoid desiccation and progressive stromal melt of the underlying cornea, which is a common complication in eyes with severe DED. In this review, we will focus on Kpro designs that have been developed to survive in eyes with the hostile environment of severe DED. Their outcomes in such eyes will be discussed.

Postoperative Complications in the Primary Tube Versus Trabeculectomy Study During 5 Years of Follow-up

PURPOSE

To describe postoperative complications encountered in the Primary Tube Versus Trabeculectomy (PTVT) Study during 5 years of follow-up.

DESIGN

Multicenter randomized clinical trial.

PARTICIPANTS

A total of 242 eyes of 242 patients with medically uncontrolled glaucoma and no previous incisional ocular surgery, including 125 patients in the tube group and 117 patients in the trabeculectomy group.

METHODS

Patients were enrolled at 16 clinical centers and randomly assigned to treatment with a tube shunt (350-mm2 Baerveldt glaucoma implant) or trabeculectomy with mitomycin C (MMC, 0.4 mg/ml for 2 minutes).

MAIN OUTCOME MEASURES

Surgical complications, reoperations for complications, visual acuity, and cataract progression.

RESULTS

Early postoperative complications occurred in 24 patients (19%) in the tube group and 40 patients (34%) in the trabeculectomy group (P = 0.013). Late postoperative complications developed in 27 patients (22%) in the tube group and 32 patients (27%) in the trabeculectomy group (P = 0.37). Serious complications producing vision loss and/or requiring a reoperation were observed in 3 patients (2%) in the tube group and 9 patients (8%) in the trabeculectomy group (P = 0.11). Cataract progression was seen in 65 patients (52%) in the tube group and 52 patients (44%) in the trabeculectomy group (P = 0.30). Surgical complications were not associated with a higher rate of treatment failure (P = 0.61), vision loss (P = 1.00), or cataract progression (P = 0.77) CONCLUSIONS: A large number of surgical complications were observed in the PTVT Study, but most were transient and self-limited. The incidence of early postoperative complications was higher following trabeculectomy with MMC than with tube shunt surgery. The rates of late postoperative complications, serious complications, and cataract progression were similar with both surgical procedures after 5 years of follow-up. Surgical complications did not increase the risk of treatment failure, vision loss, or cataract progression.

[The research progress of mesenchymal stem cell induction and differentiation into corneal tissue]

Keratopathy is one of the most important blinding eye diseases in the world. Corneal opacity caused by keratopathy can seriously damage visual function. For example, corneal ulcer can lead to perforation and even loss of the eyeball. Although corneal transplantation is a routine treatment in clinical practice, there are not only a serious shortage of corneal donors in our country, but also various complications after keratoplasty that can not be avoided. In recent years, with the rapid development of regenerative medicine, it has been found that mesenchymal stem cells can differentiate into a variety of functional cells including corneal tissue under suitable induction conditions, which has a broad prospect of clinical application. This finding provides new ideas and methods for the treatment of keratopathy and corneal blindness in many aspects. This article reviews the research status of induction methods of mesenchymal stem cells in various specialties, particularly in the corneal subspecialty.

Osteo-odonto-keratoprosthesis according to Strampelli original technique: A retrospective study with up to 30 years of follow-up

PURPOSE

To describe clinical, anatomical, and visual outcomes obtained from a long-term follow-up of 59 patients who underwent osteo-odonto-keratoprosthesis (OOKP) using the original Strampelli technique.

DESIGN

retrospective clinical cohort study.

METHODS

82 eyes of 59 patients who underwent OOKP surgery between 1969 and 2011 were included. Patients' clinical characteristics before surgery as well as complications and further surgeries until the end of follow-up were recorded. BCVA was revised before surgery and at 1 month, 1 year and every 5 years until the 30th year of follow-up.

RESULTS

Mean follow-up post-OOKP was 27.4±11.2 years (2.4-52). The most frequent cause of blindness was chemical injuries (71%). OOKP integrity was maintained in 77 out of 82 eyes until the end of follow-up (94%). Excluding the cataract, acquired glaucoma was the most frequent complication with a prevalence at 10 years of 36%. Mean BCVA improved from 2.60±0.32 at presentation to 0.40±0.65 at 1 year and 1.21±1.19 logMAR at 30 years. Overall, 51% of the included eyes attained a BCVA better than 0.05 logMAR and a stabilization of BCVA was observed for the first 10 years of follow-up post-OOKP. Better BCVA outcomes were observed in the Stevens-Johnson Syndrome or Toxic Epidermal Necrolysis (SJS/TEN) group, while glaucoma showed not to significantly affect visual acuity.

CONCLUSIONS

The original OOKP still represents a valid surgical choice, durable over time, for restoring vision in end-stage corneal blindness patients not eligible for a corneal transplant.

The First Epiretinal Implant for Hereditary Blindness in the Asia-Pacific Region

In February 2013, the Argus® II Retinal Prosthesis System (Second Sight Medical Products, Inc., Sylmar, CA, US) became the first "bionic eye" approved by the FDA to restore useful vision in patients previously blinded by end-stage retinitis pigmentosa, a hereditary, progressive degeneration of the outer retinal photoreceptor cells. The system captures and converts an external optical input into an electrical signal that activates an epiretinal electrode array on the inner surface of the retina. This signal bypasses dysfunctional photoreceptors and directly stimulates the functional inner retina, thus transmitting information to the visual cortex and creating artificial vision. This article describes the first implantation of the Argus II Retinal Prosthesis System in the Asia-Pacific region, which occurred in a deaf and blind 72-year-old Japanese American woman with Usher syndrome. At 57 months after her operation, the patient uses the device daily to perform visual tasks, and the microelectrode array remains in the proper position on the macula. This case demonstrates the long-term safety and efficacy of the Argus II epiretinal implant, which allowed a functionally blind patient to gain meaningful vision.

Learning to perceive shape from temporal integration following late emergence from blindness

Visual perception requires massive use of inference because the 3D structure of the world is not directly provided by the sensory input.¹ Particularly challenging is anorthoscopic vision-when an object moves behind a narrow slit such that only a tiny fraction of it is visible at any instant. Impressively, human observers correctly recognize objects in slit-viewing conditions by early childhood,^2,3 via temporal integration of the contours available in each sliver.^4,5 But can this capability be acquired if one has been effectively blind throughout childhood? We studied 23 Ethiopian children which had bilateral early-onset cataracts-resulting in extremely poor vision in infancy-and surgically treated only years later. We tested their anorthoscopic vision, precisely because it requires a cascade of demanding visual inference processes to perceive veridical shape. Failure to perform the task may allow mapping specific bottlenecks for late visual recovery. The patients' visual acuity typically improved substantially within 6 months post-surgery. Still, at this stage many were unable to recover shape under slit-viewing conditions, although they could infer the direction of global motion. However, when retested later, almost all patients could judge shape in slit-conditions necessitating temporal integration. This acquired capability often transferred to novel stimuli, in similar slit-viewing conditions. Thus, learning was not limited to the specific visual features of the original shapes. These results indicate that plasticity of sophisticated visual inference routines is preserved well into adolescence, and vision restoration after prolonged early-onset blindness is feasible to a greater extent than previously thought.

Keratoprosthesis: Current Choices and Future Development

Keratoprosthesis (KPro) is the last resort for corneal blindness. Boston KPro I and osteo-odonto-keratoprosthesis (OOKP) have the most favorable outcomes for their respective indications. Recently, better outcomes have been achieved for these 2 devices mainly because of improvements in postoperative care and modifications in complication management through years of experience and research. Unfortunately, some patients cannot benefit from these KPros due to lack of access to devices, trained surgeons, or both. Boston KPro I is heading toward a more affordable variation particularly for patients in developing countries. In addition, more patients with severely compromised ocular surface will be candidates for Boston KPro II variants. Biosynthetic or synthetic OOKP analogues will make the operation less complex and suitable for patients without canine tooth.

Cataract Services are Leaving Widows Behind: Examples from National Cross-Sectional Surveys in Nigeria and Sri Lanka

The Sustainable Development Goals aim to leave no one behind. We explored the hypothesis that women without a living spouse—including those who are widowed, divorced, separated, and never married—are a vulnerable group being left behind by cataract services. Using national cross-sectional blindness surveys from Nigeria (2005–2007; n = 13,591) and Sri Lanka (2012–2014; n = 5779) we categorized women and men by marital status (married/not-married) and place of residence (urban/rural) concurrently. For each of the eight subgroups we calculated cataract blindness, cataract surgical coverage (CSC), and effective cataract surgical coverage (eCSC). Not-married women, who were predominantly widows, experienced disproportionate cataract blindness—in Nigeria they were 19% of the population yet represented 56% of those with cataract blindness; in Sri Lanka they were 18% of the population and accounted for 54% of those with cataract blindness. Not-married rural women fared worst in access to services—in Nigeria their CSC of 25.2% (95% confidence interval, CI 17.8–33.8%) was far lower than the best-off subgroup (married urban men, CSC 80.0% 95% CI 56.3–94.3); in Sri Lanka they also lagged behind (CSC 68.5% 95% CI 56.6–78.9 compared to 100% in the best-off subgroup). Service quality was also comparably poor for rural not-married women—eCSC was 8.9% (95% CI 4.5–15.4) in Nigeria and 37.0% (95% CI 26.0–49.1) in Sri Lanka. Women who are not married are a vulnerable group who experience poor access to cataract services and high cataract blindness. To “leave no one behind”, multi-faceted strategies are needed to address their needs.

The Aurolab Keratoprosthesis (KPro) versus the Boston Type I Kpro: 5-year Clinical Outcomes in 134 Cases of Bilateral Corneal Blindness

PURPOSE

To compare the clinical outcomes of Boston Type I keratoprosthesis (Boston Kpro) with its low-cost version, the Aurolab Kpro (auroKPro).

DESIGN

Retrospective comparative case series.

METHODS

This study included 134 eyes of 130 patients with severe bilateral corneal blindness but with wet ocular surfaces. The patients underwent either Boston Kpro (n = 78) or auroKPro (n = 56) implantation based on the device availability and patient's affordability. The primary outcome measurements were anatomical retention (defined as absence of device extrusion, exchange, or explantation) and functional recovery of 20/200 or better visual acuity at yearly time points until 5-years of follow-up.

RESULTS

Limbal stem cell deficiency was the most common indication (60.5%) for surgery, followed by multiple failed grafts (35%). Both groups were comparable at baseline with respect to indications for surgery and associated ocular co-morbidities (P > 0.05). The overall anatomical retention rates were similar in the Boston Kpro (55 of 78, 70.5%) and auroKPro (35 of 56, 62.5%) groups (P = 0.11). Kaplan-Meier survival rates at 5 years of follow-up were greater for the Boston Kpro with respect to both anatomical retention (63 ± 6% vs. 43.4 ± 10%, respectively; P = 0.057) and functional recovery (42.4 ± 6% vs. 32.2 ± 7%, respectively; P = 0.345), but these differences were not statistically significant. Complications such as intraoperative device breakage (7%) and postoperative extrusions (12.5%) were significantly more common with the auroKPro (P = 0.023).

CONCLUSIONS

Both the auroKPro and the Boston Kpro are effective treatment options for patients with severe bilateral corneal blindness. The auroKPro can be considered an alternative to the Boston Kpro when affordability or availability of the Boston Kpro is a limiting factor.

First Simultaneous Explantation and Re-Implantation of an Argus II Retinal Prosthesis System

A 59-year-old blind woman with retinitis pigmentosa had undergone implantation of an Argus II system without complications and took advantage of the system for 7 months. Due to a technical error of the system, the glasses of the prosthesis developed increased heat generation, making the use of the system unbearable. Because of the initial satisfaction and high motivation of the patient, it was decided to strive for an implant exchange. In a 4-hour surgery session, the implant was removed and a new system was implanted. Hereby, several critical surgery steps could be identified that are important to consider for future surgeries. Besides a strong fibrotic scarring of conjunctiva and tenon aggravating the extraction of the extraocular components, the preparation of the sclerotomy proved to be difficult for achieving water tightness. Furthermore, the extraction of the retinal tack and the repositioning of the new array were challenging steps. During the postoperative course, a severe hemorrhagic choroidal detachment occurred but resolved without surgical intervention. The implant was well-placed and showed good function. The exchange of an Argus II is feasible, however, with the challenge of hypotony and hemorrhage as well as possible fibrosis complicating the repositioning of the chip. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:462-465.].

Changing trends of blindness, visual impairment and cataract surgery in Bhutan: 2009-2018

Purpose

To obtain new rapid assessment of avoidable blindness (RAAB) data on the prevalence, causes and trends of blindness, visual impairment and cataract surgery; and compare the new 2018 data with the older RAAB 2009 data.

Methodology

The second nationwide RAAB used android based mRAAB technique and technology for data collection. Using the compact segment sampling probability proportionate to size, 5,050 participants from 101 clusters of 50 people aged 50 years and older were enrolled through house-to-house visits. Eligible participants received ophthalmic examination and interview by the ophthalmologist-led emuneration team as per the RAAB protocol.

Results

The age-sex adjusted magnitude of bilateral blindness in Bhutan was 1.0% (95% Confidence Interval, CI 0.5–1.4) with relatively higher prevalence in rural population (Odds Ratio, OR 1.5, p = 0.13) and women (OR 1.6, p = 0.06). Untreated cataract accounted for the most of blindness (53.8%), severe vision impairment (57.1%), and moderate visual impairment (65.3%); uncorrected refractive error was the main cause of early visual impairment (46.7%). Cataract Surgical Coverage was 86.1% with relatively better coverage in men (76.7% men; 73.1% female) and urban population (79.2% urban; 70.2% rural). Good cataract surgical outcome was achieved in 67.3% and leading cause of poor outcome was ocular comorbidity (43.6%). Accessibility was a significant barrier to the uptake of cataract surgical services.

Conclusion

There is a 33% reduction in blindness from 1.5% to 1.0%, since the first RAAB survey in 2009. In order to further reduce blindness and visual impairment, Bhutan should continue to implement long-term strategic action plan for eye health focused on strengthening primary eye care and comprehensive eye care service.

Optical Coherence Tomography in Patients With the Subretinal Implant Retina Implant Alpha IMS

BACKGROUND AND OBJECTIVE

The aim of this study was to assess changes in retinal structure and thickness after subretinal implantation of the Retina Implant Alpha IMS (Retina Implant AG, Reutlingen, Germany).

PATIENTS AND METHODS

Spectral-domain optical coherence tomography (SD-OCT) imaging was performed to assess the structure and thickness of the retina anterior to the microphotodiode array preoperatively, within 6 weeks and 6 months ± 1 month after implantation. Thickness measurements were performed using the distance tool of the built-in software. Three thickness measurements were performed in each of the four quadrants of the retina on the microchip within 6 weeks and 6 months ± 1 month after implantation.

RESULTS

The mean ± standard deviation change in retinal thickness from within 6 weeks to 6 months ± 1 month after implantation in all four quadrants combined was 24 μm ± 68 μm. None of the tested variables (location, time, or their interaction) had a statistically significant effect on the mean retinal thickness (P = .961, P = .131, and P = .182, respectively; n = 19).

CONCLUSION

The authors report on qualitative and quantitative findings in retinal structure in 27 patients after subretinal implantation of the Retina Implant Alpha IMS using OCT technology. No significant changes of retinal thickness could be observed in a period of 6 months after surgery. With more patients receiving subretinal implants and with advanced OCT technology, the data set will be extended to study possible changes in retinal structure in finer detail. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:993-999.].

Pawan Sinha

An interview with Pawan Sinha, a computational neuroscientist interested in vision, particularly visual object discovery, something he has been investigating via 'Project Prakash' on children in rural India born with treatable blindness.

Outcomes of Cataract Surgery in Urban and Rural Population in the South Indian State of Andhra Pradesh: Rapid Assessment of Visual Impairment (RAVI) Project

OBJECTIVE

To assess the visual outcomes after cataract surgery among urban and rural population aged ≥40 years in the South India state of Andhra Pradesh.

METHODS

A population based cross-sectional study was conducted in which 7800 subjects were sampled from two rural and one urban location. Visual Acuity was assessed and eye examination were performed by trained personnel. A questionnaire was used to collect personal and demographic information, and history of cataract surgery. Blindness and moderate Visual Impairment (MVI) was defined as presenting VA <6/60 and <6/18 to 6/60 in the better eye respectively.

RESULTS

In total, 7378 (94.6%) were examined. Of these, 1228 eyes of 870 individuals were operated for cataract. The mean age of operated subjects was 63.7 years (SD: 10.7 years). Overall, 56.3% of those operated were women, 76% were illiterate and 42% of them were using spectacles after cataract surgery. Even after surgery, 12.2% of the operated eyes had MVI and blindness was seen in 14.7% of the eyes. A significantly higher proportion of subjects in urban area had good outcome as compared to those in the rural area (p = 0.01). Uncorrected refractive error (58.7%) was the leading cause of MVI, and posterior segment disease (34.3%) was the leading cause of blindness. On applying multiple logistic regression, risk factors for poor outcomes were age ≥ 70 years (OR: 1.9, 95% CI: 1.3-2.8), rural residence (OR: 1.3, 95% CI:1.0-1.8) and presence of aphakia (OR: 8.9, 95% CI: 5.7-13.8).

CONCLUSIONS

Post cataract surgery, refractive errors remain an important correctable cause of MVI, in the south Indian state of Andhra Pradesh. The correction of refractive errors is required to provide good visual recovery and achieve the benefit of cataract surgery.

Ethical Considerations of Whole-Eye Transplantation

Whole eye transplantation (WET) remains experimental. Long presumed impossible, recent scientific advances regarding WET suggest that it may become a clinical reality. However, the ethical implications of WET as an experimental therapeutic strategy remain largely unexplored. This article evaluates the ethical considerations surrounding WET as an emerging experimental treatment for vision loss. A thorough review of published literature pertaining to WET was performed; ethical issues were identified during review of the articles.

Prevalence of blindness and cataract surgical outcomes in Takeo Province, Cambodia

PURPOSE

To estimate the prevalence of blindness and cataract surgical outcomes in persons 50 years or older above in Takeo Province, Cambodia.

DESIGN

A population based survey.

METHODS

A total of 93 villages were selected through probability proportionate to size using the Rapid Assessment of Avoidable Blindness methodology. Households from 93 villages were selected using compact segment sampling. Visual acuity (VA) of 4650 people 50 years or older was tested and lens status and cause of visual impairment were assessed.

RESULTS

The response rate was 96.2%. The age- and sex-adjusted prevalence of bilateral blindness [presenting visual acuity (PVA) <3/60 in the better eye] was 3.4% (95% confidence interval, 2.8%-4.0%), resulting in an estimated 4187 people blind in Takeo Province. The age- and sex-adjusted prevalence of low vision (PVA <6/18 to 3/60) was 21.1%, an estimated 25,900 people. Cataract surgical coverage in the bilaterally blind was 64.7% (female 59.5%, male 78.1%). Cataract surgical outcome was poor (best-corrected visual acuity <6/60) in only 7.7% and good in 88.7% (best-corrected visual acuity ≥6/18) of eyes operated in the last 5 years before the survey.

CONCLUSIONS

The cataract surgical coverage for women is less than that for men. The increased life expectancy in Cambodia and the fact that women constitute 60.6% of the population (aged ≥50 years) at Takeo Province could have had an impact on cataract workload and high prevalence of blindness. A repeated survey using the same methodology after 8-12 years might be helpful in proving genuine change over time.

Unsutured phakic implantation of a black intraocular lens in the sulcus to treat leukocoria

We describe a 40-year-old woman with von Hippel-Lindau syndrome, secondary chronic exudative retinal detachment, and white cataract with consequent leukocoria. Because the cataract was contracted and calcified, a black Morcher 85F poly(methyl methacrylate) IOL was implanted in the ciliary sulcus anterior to the lens to prevent posterior capsule rupture and potential destabilization of the retinal detachment with a risk for phthisis. Excellent centration of the black IOL was achieved with good cosmetic outcome and without postoperative uveitis or glaucoma. We suggest that this is a rare indication for implantation of an IOL designed for the sulcus but in the presence of the crystalline lens. This approach makes IOL removal, if necessary at a later date, relatively straightforward.

Financial Disclosure

No author has a financial or proprietary interest in any material or method mentioned.

Retinal prosthesis

Retinal prosthesis has been translated from the laboratory to the clinic over the past two decades. Currently, two devices have regulatory approval for the treatment of retinitis pigmentosa. These devices provide partial sight restoration and patients use this improved vision in their everyday lives. Improved mobility and object detection are some of the more notable findings from the clinical trials. However, significant vision restoration will require both better technology and improved understanding of the interaction between electrical stimulation and the retina. This paper reviews the recent clinical trials and highlights technology breakthroughs that will contribute to next generation of retinal prostheses.

Corneal blindness and xenotransplantation

Approximately 39 million people are blind worldwide, with an estimated 285 million visually impaired. The developing world shoulders 90% of the world's blindness, with 80% of causative diseases being preventable or treatable. Blindness has a major detrimental impact on the patient, community, and healthcare spending. Corneal diseases are significant causes of blindness, affecting at least 4 million people worldwide. The prevalence of corneal disease varies between parts of the world. Trachoma, for instance, is the second leading cause of blindness in Africa, after cataracts, but is rarely found today in developed nations. When preventive strategies have failed, corneal transplantation is the most effective treatment for advanced corneal disease. The major surgical techniques for corneal transplantation include penetrating keratoplasty (PK), anterior lamellar keratoplasty, and endothelial keratoplasty (EK). Indications for corneal transplantation vary between countries, with Fuchs' dystrophy being the leading indication in the USA and keratoconus in Australia. With the exception of the USA, where EK will soon overtake PK as the most common surgical procedure, PK is the overwhelming procedure of choice. Success using corneal grafts in developing nations, such as Nepal, demonstrates the feasibility of corneal transplantation on a global scale. The number of suitable corneas from deceased human donors that becomes available will never be sufficient, and so research into various alternatives, for example stem cells, amniotic membrane transplantation, synthetic and biosynthetic corneas, and xenotransplantation, is progressing. While each of these has potential, we suggest that xenotransplantation holds the greatest potential for a corneal replacement. With the increasing availability of genetically engineered pigs, pig corneas may alleviate the global shortage of corneas in the near future.

Failure of chemotherapy in the first reported cases of Acanthamoeba keratitis in Pakistan

Acanthamoeba keratitis is a painful and progressive infection of the cornea that can result in loss of vision. Here, for the first time in Pakistan, we report two cases of Acanthamoeba keratitis. The first patient was a 37-year-old female who presented with severe itching, redness, pain, along with loss of vision. The patient was a regular soft contact lens wearer. The second patient was a 25-year-old female who had been using soft contact lenses for the past two years. She presented with a burning sensation and extreme pain, along with loss of vision. Both patients were treated for a possible microbial keratitis with topical moxifloxacin hydrochloride drops, vancomycin drops, propamidine isethionate ointment, amphotericin B drops, and amikacin drops. However, the response was inadequate and both patients were referred for corneal transplant. Acanthamoeba castellanii was isolated by placing contact lenses and contact lens cases on non-nutrient agar plates containing a lawn of non-invasive Escherichia coli K-12 HB101 bacteria. The polymerase chain reaction (PCR) using genus-specific probes confirmed the identity of Acanthamoeba spp., whereas the morphological characteristics of trophozoites and cysts were suggestive of A. castellanii in both cases. With growing use of contact lenses for vision correction/cosmetic use coupled with sub-standard lens care in this region and the possibility of non-contact lens-associated Acanthamoeba keratitis, a need for increased awareness of this sight-threatening infection is discussed further.

Fungal endophthalmitis associated with compounded products

Fungal endophthalmitis is a rare but serious infection. In March 2012, several cases of probable and laboratory-confirmed fungal endophthalmitis occurring after invasive ocular procedures were reported nationwide. We identified 47 cases in 9 states: 21 patients had been exposed to the intraocular dye Brilliant Blue G (BBG) during retinal surgery, and the other 26 had received an intravitreal injection containing triamcinolone acetonide. Both drugs were produced by Franck's Compounding Lab (Ocala, FL, USA). Fusarium incarnatum-equiseti species complex mold was identified in specimens from BBG-exposed case-patients and an unopened BBG vial. Bipolaris hawaiiensis mold was identified in specimens from triamcinolone-exposed case-patients. Exposure to either product was the only factor associated with case status. Of 40 case-patients for whom data were available, 39 (98%) lost vision. These concurrent outbreaks, associated with 1 compounding pharmacy, resulted in a product recall. Ensuring safety and integrity of compounded medications is critical for preventing further outbreaks associated with compounded products.

Analysis of prognostic factors of endoscopic optic nerve decompression in traumatic blindness

CONCLUSIONS

Hemorrhage within the ethmoid and/or sphenoid sinus and an interval between the time of injury and the time of operation exceeding 3 days are the risk factors for the visual prognosis of traumatic blindness.

OBJECTIVES

To investigate the therapeutic efficacy of endoscopic optic nerve decompression in the treatment of traumatic blindness and to evaluate the relevant prognostic factors.

METHODS

Eighty-five cases of traumatic blindness were analyzed retrospectively. Univariate analysis and multiple logistic regression were performed to evaluate potential prognostic factors.

RESULTS

The overall rate of vision acuity improvement was 44.7% (38 of 85). Univariate analysis indicated that hemorrhage within the ethmoid and/or sphenoid sinus was significantly associated with unrecovered visual acuity. However, multiple logistic regression analysis identified that an interval between the time of injury and the time of operation exceeding 3 days, and hemorrhage within the ethmoid and/or sphenoid sinus were significantly correlated with the efficacy of treatment of traumatic blindness.

Life with anotner cornea: impact of corneal transplantation and eye banking in Ethiopia

PURPOSE

Although clinical success of corneal transplantation is encouraging, its impact on the lives of beneficiaries is overlooked. We tried to understand how visually impaired people perceive the effect of a recently introduced corneal transplantation and eye banking service.

METHODS

In-depth interviews were conducted among 20 patients with corneal visual impairment. All had transplantation surgery at Minilik II Hospital, mostly with corneas harvested and processed by Eye Bank of Ethiopia. The qualitative data focused on their experiences regarding changes in quality of life, visual outcome, and attitude toward corneal donation. Data were analyzed using the thematic framework approach.

RESULTS

Before the transplantation, patients suffered from disability and low self-esteem but remained hopeful. After the transplantation, they felt satisfied with whatever visual gain they got and described the process as 'a miracle'. They believed their life had somewhat changed for the better as they became independent and capable again. They also felt extremely grateful to donors and became advocates for corneal donation.

CONCLUSION

The availability of a corneal harvesting and transplantation service is making positive impacts on the lives of visually impaired individuals in Ethiopia. However, the extent of this service should be widened to have a significant effect on the magnitude of corneal blindness across the country.

Early lens ablation causes dramatic long-term effects on the shape of bones in the craniofacial skeleton of Astyanax mexicanus

The Mexican tetra, Astyanax mexicanus, exists as two morphs of a single species, a sighted surface morph and a blind cavefish. In addition to eye regression, cavefish have an increased number of taste buds, maxillary teeth and have an altered craniofacial skeleton compared to the sighted morph. We investigated the effect the lens has on the development of the surrounding skeleton, by ablating the lens at different time points during ontogeny. This unique long-term study sheds light on how early embryonic manipulations on the eye can affect the shape of the adult skull more than a year later, and the developmental window during which time these effects occur. The effects of lens ablation were analyzed by whole-mount bone staining, immunohistochemisty and landmark based morphometric analyzes. Our results indicate that lens ablation has the greatest impact on the skeleton when it is ablated at one day post fertilisation (dpf) compared to at four dpf. Morphometric analyzes indicate that there is a statistically significant difference in the shape of the supraorbital bone and suborbital bones four through six. These bones expand into the eye orbit exhibiting plasticity in their shape. Interestingly, the number of caudal teeth on the lower jaw is also affected by lens ablation. In contrast, the shape of the calvariae, the length of the mandible, and the number of mandibular taste buds are unaltered by lens removal. We demonstrate the plasticity of some craniofacial elements and the stability of others in the skull. Furthermore, this study highlights interactions present between sensory systems during early development and sheds light on the cavefish phenotype.

Acute bilateral blindness as a presenting symptom of Non-Hodgkin's lymphoma

NHL usually presents with lymphadenopathy or symptoms related to compression by the primary tumor of surrounding structures. While the head and neck region is a common site of involvement, blindness is rarely a presenting symptom. We report here the case of a child who presented to the emergency room with acute bilateral loss of vision and no other symptoms. Cranial imaging studies revealed a solid mass of the skull base with compression on optic nerves. Diagnosis of Burkitt's lymphoma was confirmed after biopsy. The patient had partial vision improvement two days after optic nerve decompression which was done immediately at the night of presentation.

Prevalence, causes and socio-economic determinants of vision loss in Cape Town, South Africa

Purpose

To estimate the prevalence and causes of blindness and visual impairment in Cape Town, South Africa and to explore socio-economic and demographic predictors of vision loss in this setting.

Methods

A cross sectional population-based survey was conducted in Cape Town. Eighty-two clusters were selected using probability proportionate to size sampling. Within each cluster 35 or 40 people aged 50 years and above were selected using compact segment sampling. Visual acuity of participants was assessed and eyes with a visual acuity less than 6/18 were examined by an ophthalmologist to determine the cause of vision loss. Demographic data (age, gender and education) were collected and a socio-economic status (SES) index was created using principal components analysis.

Results

Out of 3100 eligible people, 2750 (89%) were examined. The sample prevalence of bilateral blindness (presenting visual acuity <3/60) was 1.4% (95% CI 0.9–1.8). Posterior segment diseases accounted for 65% of blindness and cataract was responsible for 27%. The prevalence of vision loss was highest among people over 80 years (odds ratio (OR) 6.9 95% CI 4.6–10.6), those in the poorest SES group (OR 3.9 95% CI 2.2–6.7) and people with no formal education (OR 5.4 95% CI 1.7–16.6). Cataract surgical coverage was 68% in the poorest SES tertile (68%) compared to 93% in the medium and 100% in the highest tertile.

Conclusions

The prevalence of blindness among people ≥50 years in Cape Town was lower than expected and the contribution of posterior segment diseases higher than previously reported in South Africa and Sub Saharan Africa. There were clear socio-economic disparities in prevalence of vision loss and cataract surgical coverage in this setting which need to be addressed in blindness prevention programs.

Project Prakash: Challenging the critical period: Association of Research in Vision and Ophthalmology National Meeting

Project Prakash is an organization that reverses congenital blindness in children and adolescents in rural India with the hypothesis that these children will be able to recover some of their vision even though their visual system did not develop normally. This hypothesis challenges the scientific dogma established by the Nobel-prize winning research of Hubel and Wiesel that the brain cannot adapt to visual input after being completely deprived of vision during the critical first few months and years of life. Dr. Pawan Sinha presented his work at the largest and most respected ophthalmological research meeting, the Association for Research in Vision and Ophthalmology (ARVO), in Fort Lauderdale, Florida, on May 4, 2011.

Osteo-odonto-keratoprosthesis for end-stage cornea blindness

We report the first case of Osteo-odonto-keratoprosthesis (OOKP) who successfully underwent surgery in Malaysia following a grade 4 (severe) chemical injury in both eyes in 2006. The patient's left eye was eviscerated and his right eye underwent penetrating keratoplasty. However, the corneal graft failed and became opaque. His right eye could only perceive light. The OOKP was offered to him hoping to recover some functional vision. He underwent a 2-stage surgery to implant the OOKP into his right eye. However, 2 months post-operation, he developed vitreous haemorrhage. A successful pars plana vitrectomy (PPV) was performed via the limited view through the lens. He attained a final visual acuity of 6/60 (N36). He was able to mobilize more independently, feed, dress himself and read large print.

Anatomical and functional outcomes of surgery of rhegmatogenous retinal detachment

DOI: 10.3126/nepjoph.v3i1.4295Nepal J Ophthalmol 2011;3(5):93

Angiographic findings following tack fixation of a wireless epiretinal retina implant device in blind RP patients

BACKGROUND

The fixation of polyimide stimulator foils as the basic substrate of epiretinal prostheses by using retinal tacks may cause retinal or choroidal alterations such as retinal proliferations or choroidal neovascularizations. During the prospective trial for the semichronical testing of a wireless intraocular retinal implant (EPIRET3) we investigated alterations in angiographic findings during implantation and after explantation of the device, to detect potential vascular pathologies at the fixation site or elsewhere.

METHODS

As the final step of the implantation surgery in six blind patients, the stimulator was placed on the retinal surface using retinal tacks. For the detection of possible morphological or vascular alterations committed by the implant fluorescein angiography (FA) was performed 1 day before and 4 weeks after implantation surgery, as well as at the final visit 5 months after explantation.

RESULTS

Following implantation surgery funduscopy and FA did not reveal any evidence of either vascular pathologies or choroidal neovascularisations (CNV), in addition, no cystoid macular edema (CME) occurred after 4 weeks. At the 6-month follow-up visit, we found a mild epiretinal gliosis formation in four patients. In one patient a retinal break occurred during explantation, requiring a temporary silicone-oil endotamponade. At the final visit, we observed a focal proliferative vitreoretinopathy (PVR) reaction without activity, while there was no evidence for a CNV formation in that area.

CONCLUSIONS

The FA findings confirm our previous results on the safety of the EPIRET3 system, which was tolerated in all patients but revealed a certain risk profile in regard to the stimulator fixation. While there was no evidence for newly occurred CME or CNV during the follow-up visits, nevertheless gliosis or even PVR reaction at the tack's fixation site suggests the need to develop alternative fixation procedures of epiretinal stimulators.

[Availability of patients living in rural areas, to have surgical method of treatment of cataract and glaucoma]

Using modern surgical treatment on patients that live in rural areas, with cataract and glaucoma is not sufficient. There is insufficient expertise of ophthalmologists, low level of human, logistical and financial resource support for eye hospitals, low level of motivation and socio-psychological problems among patients, creating a favorable situation in Ukraine for further growth of low vision and blindness in rural areas. Institutional solutions of existing problems are proposed.