Corneal blindness in Plato's cave: the acting forces to prevent and revert corneal opacity. Part I: epidemiology and new physiopathological concepts.

The burden of corneal blindness and visual deficiency can be felt worldwide. Its association with several endemic diseases such as childhood blindness, trauma, infectious keratitis (including variants caused by herpes, hanseniasis, and fungi), vitamin A deficiency, diabetes mellitus, and other dry eye syndromes reflects its poorly understood underlying mechanisms and suggests that the actual frequency of the disease is underestimated. The low effectiveness of preventive and therapeutic strategies against corneal scarring or deformity predicts a high frequency of patients with corneal blindness in the future. Corneal blindness is associated with environmental factors and socioeconomic limitations that restrain health assistance and maintain a modest efficiency of the current therapeutic strategies for resolving corneal diseases in large-scale programs. We present here a critical review of the concepts associated with corneal blindness that need to be considered when planning strategies to prevent and treat corneal blindness worldwide (to be able to leave Plato's cave, where corneal blindness is encaged.

Ocular leprosy.

Ocular involvement in leprosy is estimated to be 70-75%, about 10-50% of leprosy patients suffer from severe ocular symptoms, and blindness occurs in about 5% of patients. The disease leads to many ophthalmologic symptoms and signs in the range of the eyeball itself, as well as of the bulb adnexa, ie, eyebrows, eyelids with eyelashes, and lacrimal drainage system. Especially dangerous are complications of lagophthalmos and corneal hypoanesthesia, neurotrophic or infectious keratitis, and iridocyclitis and cataract formation, which may lead to significant decrease of visual acuity or even blindness. Multidrug treatment rapidly interrupts transmission of Mycobacterium leprae by infectious patients, but even after being completed, it does not guarantee the withholding of ocular complications.

Ocular leprosy

Ocular involvement in leprosy is estimated to be 70-75%, about 10-50% of leprosy patients suffer from severe ocular symptoms, and blindness occurs in about 5% of patients. The disease leads to many ophthalmologic symptoms and signs in the range of the eyeball itself, as well as of the bulb adnexa, ie, eyebrows, eyelids with eyelashes, and lacrimal drainage system. Especially dangerous are complications of lagophthalmos and corneal hypoanesthesia, neurotrophic or infectious keratitis, and iridocyclitis and cataract formation, which may lead to significant decrease of visual acuity or even blindness. Multidrug treatment rapidly interrupts transmission of Mycobacterium leprae by infectious patients, but even after being completed, it does not guarantee the withholding of ocular complications.

Ocular manifestation in treated multibacillary Hansen's disease.

PURPOSE: To report the prevalence of ocular morbidity in patients with treated multibacillary Hansen's disease (HD) using modern ophthalmic diagnostic techniques in a rural community endemic for HD. DESIGN: Cross-sectional, observation study. PARTICIPANTS: All patients with multibacillary HD who had completed their multidrug therapy and who resided in 4 defined geographical areas in Vellore, Tamil Nadu, India. METHODS: All participants underwent a complete eye examination that included slit-lamp examination, esthesiometry, gonioscopy, applanation tonometry, and dilated fundus examination, including a stereobiomicroscopic examination of the fundus at an ophthalmic center set up for that purpose. Glaucoma suspects underwent automated perimetry using a Humphrey Field Analyzer (Humphrey Instruments, San Leandro, CA). MAIN OUTCOME MEASURES: The prevalence of various ocular disease parameters were reported as mean value with 95% confidence interval. The difference of disease prevalence between various leprosy groups was compared using an unpaired t test. The association between eye symptoms and potentially sight-threatening complications was analyzed using the chi-square test. RESULTS: Three hundred eighty-six of the 446 patients with multibacillary HD residing in the defined areas were evaluated. Four patients (1.04%; 95% confidence interval [CI], 0.0%-2.0%) were bilaterally blind; 33 (8.55%; 95% CI, 5.8%-11.3%) had unilateral blindness. Mean intraocular pressure was 12 mmHg (standard deviation, 4.1 mmHg), and prevalence of glaucoma was 3.6% (95% CI, 1.8%-5.5%). Potentially sight-threatening (PST) pathologic features (corneal anesthesia, lagophthalmos, uveitis, scleritis, and advanced glaucoma) were present in 10.4% (95% CI, 7.4%-13.4%) of patients. Significant cataracts occurred 3 times more frequently in those with polar lepromatous leprosy. The odds ratio for PST pathology in the presence of patient-reported symptoms (pain, redness, inability to close eye, burning, and irritation) was 2.9 (95% CI, 1.34-6.26). CONCLUSIONS: Patients who have completed treatment for multibacillary HD continue to have significant ocular morbidity. A history of specific eye symptoms can be the basis for referral by field staff.

Isolated lepromatous conjunctivo-corneal granuloma in a cat from Italy.

OBJECTIVE: To describe a case of a conjunctivo-corneal mass in a cat associated with acid-fast bacilli. METHODS: A 2-year-old female black European Short-Hair cat, living outdoors in a suburban environment in Italy, was referred for evaluation of a nodular, vascularized mass of 2 weeks duration. The mass involved the dorsal bulbar conjunctiva at the temporal canthus of OS and invaded the sclera and cornea. Routine ophthalmic and systemic examination, serologic testing, cytology and histology of the mass were performed. Mycobacterium specific polymerase chain reaction (PCR) of variable regions 1, 2 and 3 of the 16S ribosomal RNA (rRNA) gene was also performed. RESULTS: Neutrophils, lymphocytes, macrophages and giant cells with intracytoplasmic acid-fast bacilli were seen on cytological examination. The histological examination confirmed the presence of a granulomatous lesion with acid-fast bacilli within macrophages. Bacteriological culture of the material from the lesion was negative for Mycobacterium spp. Mycobacterium 16S rRNA gene specific PCR was positive. A diagnosis of feline leprosy was made. The owners refused any treatment, and 1 year later the lesion was still present. CONCLUSIONS: Veterinary ophthalmologists should be aware of conjunctivo-corneal leproma as an unusual symptom of leprosy.

Mycobacterium hemophilum infection presenting as filamentary keratopathy in an immunocompromised adult.

PURPOSE: To report a case of Mycobacterium hemophilum of the eye. METHODS: Case report with pathologic correlation. A 55-year-old Malaysian man with a 3-year history of graft-versus-host disease presented with dry eye and keratopathy. RESULTS: The diagnosis was not initially evident, despite biopsy specimens of the conjunctiva. Definitive diagnosis was made after dermatology consultation suggested a histoid variant of lepromatous leprosy, prompting Ziehl-Neelsen staining of the initial and subsequent conjunctival biopsies with subsequent polymerase chain reaction testing. Anti-M. hemophilum treatment resulted in prompt resolution of ocular signs. CONCLUSIONS: Mycobacterium hemophilum is a rare condition, affecting mainly immunocompromised patients. Although filamentary keratopathy has been described as common manifestations of leprosy, to date, no ocular manifestations of M. hemophilum have been described. Conjoint management with infectious disease and clinical microbiology is imperative to ensure accurate diagnosis and appropriate early intervention. The effect of systemic immunosuppression is relevant in such patients.

Prevention of blindness in leprosy and the role of the Vision 2020 Programme.

Leprosy control programmes are highly successful. As a result, leprosy control will be more and more integrated into the general health services. The existing vertical, specialized control programmes will be dismantled. Eye complications in leprosy have decreased. This is a result of earlier diagnosis and highly effective multidrug treatment (MDT) of leprosy, combined with timely treatment of secondary nerve damage by steroids. Most ocular morbidity is now found among elderly and disabled leprosy patients who were diagnosed before effective MDT treatment became available. Many of these patients live in leprosy settlements. Age-related cataract has become the leading cause of blindness in leprosy. The second cause of blindness is corneal opacification, mainly as a result of neglected exposure keratitis and corneal anaesthesia. The miotic pupils in late multibacillary leprosy, in combination with small central lens opacities, may also lead to blindness. The Vision 2020 Initiative prioritises cataract surgery. Leprosy patients should be actively included. Disabled leprosy patients can also benefit from screening programmes for refractive errors and the provision of spectacles and low vision aids. Determining the most feasible surgical methods for lagophthalmos surgery remains a challenge. For all health and eye care staff, training in leprosy and its eye complications is needed, as well as a change in attitude towards leprosy patients. Staff must be prepared to welcome them in the general health services.

Corneal blindness: a global perspective.

Diseases affecting the cornea are a major cause of blindness worldwide, second only to cataract in overall importance. The epidemiology of corneal blindness is complicated and encompasses a wide variety of infectious and inflammatory eye diseses that cause corneal scarring, which ultimately leads to functional blindness. In addition, the prevalence of corneal disease varies from country to country and even from one population to another. While cataract is responsible for nearly 20 million of the 45 million blind people in the world, the next major cause is trachoma which blinds 4.9 million individuals, mainly as a result of corneal scarring and vascularization. Ocular trauma and corneal ulceration are significant causes of corneal blindness that are often underreported but may be responsible for 1.5-2.0 million new cases of monocular blindness every year. Causes of childhood blindness (about 1.5 million worldwide with 5 million visually disabled) include xerophthalmia (350,000 cases annually), ophthalmia neonatorum, and less frequently seen ocular diseases such as herpes simplex virus infections and vernal keratoconjunctivitis. Even though the control of onchocerciasis and leprosy are public health success stories, these diseases are still significant causes of blindness--affecting a quarter of a million individuals each. Traditional eye medicines have also been implicated as a major risk factor in the current epidemic of corneal ulceration in developing countries. Because of the difficulty of treating corneal blindness once it has occurred, public health prevention programmes are the most cost-effective means of decreasing the global burden of corneal blindness.

Ocular complications of leprosy in Cameroon.

PURPOSE: This study aimed to identify the main ocular complications of leprosy in Cameroon. PATIENTS AND METHODS: It is a prospective cross-sectional study which took place from July 1998 to January 1999 in five leprosaria in Cameroon. The ophthalmological examination of all patients was performed by the same team. RESULTS: Of the 218 patients examined, 60.1% were males and 39.9% females. 72.5% had a paucibacillary leprosy and 27.5% a multibacillary form. 77.5% of patients had at least one ocular lesion and 38.3% of eyes had visual acuity < or = 1/10. Madarosis and anterior uveitis were more frequent in multibacillary forms while lagophthalmos and cataract were so in paucibacillary forms. CONCLUSION: Ocular complications are frequent in leprosy in Cameroonians. It is a true public health problem and it is important to prevent these lesions by early diagnosis and adequate treatment.

Clinical ocular study in leprosy patients at a sanitary dermatological hospital in Brazil.

This study is based upon the observation f 363 leprosy patients having different types of the disease. At the time of the examination, we did not have any previous knowledge about the type of leprosy the patients were having. Thus, the eye examination was done without the knowledge of clinical diagnosis. The ocular examination protocol covered the following: visual activity, facial muscle function, eyebrows, eyelashes, lacrimal system, pupil, eye motility, corneal sensitivity, Schirmir's test and study of the anterior segment of the ocular bulb with a slit-lamp. The study patients included 275 cases of lepromatous leprosy, 57 tuberculoid, 29 indeterminate and two dimorphous cases. The age of the patients ranged between 18 and 82 years, and 229 of them were males. Among those patients, 183 were whites, 23 were black and 157 were mulatto.

The prevalence of disabling ocular complications of leprosy: a global study.

A world-wide study on the ocular complications of leprosy has been carried out over the past ten years. The data from 4772 patients, designed to give baseline information for a five-year incidence study, have been analysed. Blindness due to leprosy was seen in 3.2% of the sample and 7.1% had Grade 2 visual disability. The causes of visual impairment in the disease are discussed and it is emphasized that a high proportion of these are preventable, particularly through the early use of multidrug therapy. The active participation of ophthalmologists in the management of the disease is still required since many of the blinding complications respond well to surgery.