Christopher Liu

The prevalence of cataract in two villages of Northern Pakistan with different levels of ultraviolet radiation

To study the effect of ultraviolet (UV) light ou the development of age-related cataract, a community-based cross-sectional study was undertaken in two villages in the mountainous Northern Areas of Pakistan. The relative UV light exposure was calculated by the UK Universities Global Atmospheric Modelling Program using the variables direct sunlight hours per day, latitude and ground reflectivity. A total of 797 subjects (410 men, 387 women) over the age of 40 years from both villages were examined for the presence of cataract. The prevalence of cataract increased with age (p<0.001) and was significantly higher in women at all ages (p<0.01). There was no significant difference in the overall prevalence of cataract between the two villages. The male population in each village was subdivided into those who worked predominantly indoors and those who worked predominantly outdoors. All women worked outdoors. There was no significant difference in the prevalence of cataract between the male outdoor workers in the two villages. The indoor workers in the village with higher UV light exposure (Hunza) had a significantly higher cataract prevalence (p<0.001) than the indoor workers in the village with lower UV light exposure (Nomol). In the village with lower UV light exposure (Nomol), the male outdoor workers had a significantly higher prevalence of cataract than the male indoor workers (p<0.001). There was no significant difference in the prevalence of cataract between the male indoor and outdoor workers in the village with Itigher UV light exposure (Hunza). Overall, these results are not strongly supportive of UV light being of major importance in cataractogenesis, but they are consistent with a saturation model of UV light as a risk factor for cataract formation.

Keratoprostheses for corneal blindness: a review of contemporary devices

According to the World Health Organization, globally 4.9 million are blind due to corneal pathology. Corneal transplantation is successful and curative of the blindness for a majority of these cases. However, it is less successful in a number of diseases that produce corneal neovascularization, dry ocular surface and recurrent inflammation, or infections. A keratoprosthesis or KPro is the only alternative to restore vision when corneal graft is a doomed failure. Although a number of KPros have been proposed, only two devices, Boston type-1 KPro and osteo-odonto-KPro, have came to the fore. The former is totally synthetic and the latter is semi-biological in constitution. These two KPros have different surgical techniques and indications. Keratoprosthetic surgery is complex and should only be undertaken in specialized centers, where expertise, multidisciplinary teams, and resources are available. In this article, we briefly discuss some of the prominent historical KPros and contemporary devices.

A brief review of Boston type-1 and osteo-odonto keratoprostheses

Globally there are ≈4.9 million bilaterally corneal blind and 23 million unilaterally corneal blind. Majority of this blindness exists in the developing countries, where resources for corneal banking and transplant surgery are less than adequate. Survival of corneal grafts gradually declines over the long term. Corneal transplantation has poor prognosis in vascularised corneal beds, ocular surface disease and viral keratitis. Keratoprosthesis (KPro) remains as a final option for end-stage ocular surface disease, multiple corneal transplant failures and high-risk corneal grafts. Boston type-1 KPro and osteo-odonto-keratoprosthesis are the two devices proven useful in recent years. Choice of a keratoprosthetic device is patient specific based on the underlying diagnosis, ocular morbidity and patient suitability. KPro surgery demands a high level of clinical and surgical expertise, lifelong commitment and extensive resources. Improvements in techniques and biomaterials may in the future provide retainable KPros that do not need regular follow-up of patients, have low complications but high retention rates and may be produced at a low cost on a mass scale to be available as ‘off the shelf’ devices. Because KPros have the potential to effectively address the burden of surgically treatable corneal blindness and may also eliminate the problems of corneal transplantation, more research is required to develop KPros as substitutes for corneal transplantation even in low-risk cases. In those countries where corneal blindness is a major liability, we need a two pronged approach: one to develop eye donation, eye banking and corneal transplantation and the second to establish centres for keratoprostheses, which are affordable and technically not challenging, in a population where default on follow-up visits are high. Until the latter is achieved, KPros should be viewed as a temporary means for visual restoration and be offered in national and supraregional specialised centres only.

Endoscopic cyclophotocoagulation in osteo-odonto-keratoprosthesis (OOKP) eyes.

tive follow-up. Therefore, a longer follow-up could be needed to comprehensively assess the safety and efficacy of this new procedure. Nardi et al also propose to debate the role of nonpenetrating glaucoma surgery (NPGS). We believe that the format of this reply is not the most appropriate context to re-launch this discussion. We would, however, like to refer to the published 10-year results of this NPGS that proves its safety and efficacy and a thoughtprovoking editorial by Jampel HD on the side effects of the current gold standard to NPGS, trabeculectomy.

Sight and comfort: complex procedures in end-stage Stevens-Johnson syndrome

AbstractBackground: We describe our complex surgical techniques in the management of a patient with end-stage ocular surface disease from Stevens–Johnson syndrome.Methods and results: Her severe discomfort due to absolute ocular dryness in the right eye was successfully treated with submandibular gland autotransplantation. Impending loss of the left eye due to repeated perforation and infection was prevented with a penetrating corneal graft covered by a new modification of a Cutler-Beard-type full-thickness lower lid skin advancement-flap. Visual rehabilitation was achieved by means of osteo-odonto-keratoprosthesis.Conclusion: The procedures described allow the preservation of eyes doomed for enucleation, relief from severe discomfort and rehabilitation from corneal blindness. Due to their complex nature they require the collaborative subspecialist surgical skills of opthalmologists and maxillofacial surgeons.

Nd:YAG laser capsulotomy: a survey of UK practice and recommendations.

Purpose TO determine national trends in YAG laser capsulotomy practice in the NHS. Methods A total of 300 consultants were randomly selected, based on a list from the Royal College of Ophthalmologists, to receive a postal questionnaire. It included 10 questions about YAG capsulotomy technique and postcapsulotomy management. Results A total of 158 (53%) replies were received; 132 (83.5%) questionnaires were completed correctly. Most consultants dilate the pupil prior to treatment (98.5%) and use contact lens (87.9%), with 63.5% reporting using contact lenses for more than one indication. Nearly half of the consultants used cruciate laser pattern (47.0%). Most aimed for capsulotomy size larger than undilated pupil size (64.4%). A total of 42.4% used postoperative steroid drops, 61.8% for 1 week. Half used postlaser intraocular pressure-lowering drops with the majority used as 1-stat dose (85.1%). A total of 60% are not reviewing cases. Cases reviewed are mostly seen by doctors, with 50% reviewed 1 month postlaser. Conclusions Though commonly practiced, there is still considerable variation in YAG laser capsulotomy practice among NHS consultant ophthalmologists. Evidence-based guidelines are warranted to lessen any unnecessary complications.

Mascara: A Cause of Thermal Burn after Cautery for Eye Lid Lesion Excision; A Case Report

Introduction: Surgical fires are rare in ophthalmic surgery. Occurrence poses disastrous risks on the eye and the patient. Mascara can play a role in the occurrence of flash fires in the vicinity of surgical fields by acting as a fuel source. Purpose: We report a case of thermal burn of eye lashes, eyelid skin and eye brow hair in a patient who was wearing mascara while cautery was applied to her eyelid lesion after excision. Results: Mascara had caused a spark fire when applying cautery after eyelid lesion excision in a young patient. Conclusion: Surgeons as well as the entire ophthalmic care team should be aware of this incident to try to minimize the risk of thermal injury by working in a make-up free ophthalmic field.

Defining Ocular Surface Disease Activity and Damage Indices by an International Delphi Consultation

PURPOSEnUnifying terminology for the description of ocular surface disease (OSD) is vital for determining treatment responses and ensuring robust clinical trial outcomes. To date, there are no agreed parameters describing activity and damage phases of disease.nnnMETHODSnA working group of international experts in OSD, oculoplastics, and uveitis from a range of backgrounds (university, teaching, district general and private hospitals) participated in a modified Delphi consensus-building exercise (October 31, 2011 to March 20, 2015). Two steering group meetings took place in which factors based upon published literature were discussed and supplemented with anonymous web-based questionnaires to refine clinical indices according to activity (reversible changes resulting directly from the inflammatory process) and/or damage (persistent, >6xa0months duration) changes resulting from previously active disease that are cumulative and irreversible).nnnRESULTSnThe recommended set of clinical parameters for the assessment of OSD encompasses 68 clinical indices and 22 ancillary grading tools (in parenthesis) subdivided by anatomical domain as follows: 4(4) tear-film, eyelid 21(3), 17(3) conjunctiva, 15(10) cornea and 11(2) Anterior Chamber/Sclera. Of these; 17(2) were considered as measures of clinical activity, 27(3) as damage, 1(8) as measures of both activity and damage. Twenty-three clinical descriptors and 9 tools did not reach the threshold for inclusion into the main standard set. These were defined as second tier parameters for use in special clinical settings.nnnCONCLUSIONnThese core parameters provide the first description of activity and damage relevant to OSD and provide a platform for the future development of scoring scales for each parameter.

Keratoprostheses: are we there yet?

Since the dawn of the 18th century, efforts to develop an ideal keratoprosthesis (KPro) have not yielded the dream KPro yet, but the journey to such an invention has given us a few notable devices and valuable experience with a number of biomaterials. The invention of a KPro started with a piece of silver-rimmed glass proposed by Pellier de Quengsy.1 We now have the latest iteration of Boston Type 1 KPro with a porous titanium back plate.2 Although the Pintucci KPro (Dacron mesh skirt and PMMA optic) and the AlphaCor (hydrogel matrix) were in clinical use for a good length of time, they failed to retain over the long term.1 We learnt that bio-integration is essential for the skirt and bio-inertness for the optic. Polymethyl methacrylate (PMMA) has largely solved the search for a stable and durable optic though the search for an ideal skirt material is still ethereal.nnAs we speak, the Boston type-1 KPro and the osteo-odonto-keratoprosthesis (OOKP) have emerged as the most sustainable devices. The Boston KPro …

Managing laminar resorption in osteo-odonto-keratoprosthesis.

OOTH IN AN EYE, RATHER AN OLD ART IN THE ERA OF newscience,knownasosteo-odonto-keratoprosthesis (OOKP), is astoundingly the most durable keratoprosthesis (KPro) to date. The original inception of using tooth as a KPro skirt material was by Strampelli in the 1960s. A single rooted tooth was transverse-sectioned and itspulpcavityenlargedtoreceiveapolymethylmethacrylate (PMMA) optical cylinder. Later, the tooth-acrylic complex was implanted into the eye. 1 Falcinelli modified this technique and pioneered the present-day OOKP technique known as ‘‘modified OOKP’’ (MOOKP). Modifications included fashioning of the lamina through the sagittal section of the tooth root, use of buccal mucosa as opposed to labial mucosa, preservation of periosteum, joining of 2 small laminae to create 1 of adequate size, cryoextraction of lens, vitrectomy, a larger biconvex optical cylinder, and a posterior draining tube. 2 Undoubtedly moving from transverse to sagittal sectioning of the tooth and other modifications have improved the success of this surgery. Yet, resorption of the lamina remains a concern. In this issue, Iyer and associates reported MOOKP surgical outcomeon85eyes using toothautografts. 3 Ofthese,44 patients suffered from Stevens-Johnson syndrome (SJS) and 37 sustained chemical injuries. The rate of laminar resorption noted in this study was 23% and was first detected at an average of 37 months in the former group and at 43 months in the latter. In our study the cumulative probability of retaining an OOKP lamina was 81% over 5 years. 4 Iyer and associates 3 made an interesting observation that laminae positioned having the thin portions facing superiorly had developed resorption on that side first. Contrarily, Stoiber and associates had implanted laminas with the thin side facing inferiorly and found resorption developing inferiorly first. 5 This emphasizes that thinner portions and thin laminae are at risk of resorption. The recommended minimum thickness for OOKP lamina is 3 mm. 6 Iyer and asso