William M. Lyle

The prevalence of selected ocular diseases and conditions.

It is useful for a clinician to know how common or rare a given ocular disease or condition is. Knowledge of a conditions prevalence provides a rough indication of how often to expect to encounter it in a clinical setting. Furthermore, knowledge of a conditions prevalence can assist in planning the health service requirements necessary to treat it. The acquisition of prevalence data from the literature, however, can be difficult and time-consuming because of the wide range of journals that have published relevant information. This article is a complication of some of the available data from the literature regarding the prevalence of many ocular diseases and conditions. It also includes a few systemic diseases with ocular involvement.

Large sample study of the effects of phenylephrine 2.5% eyedrops on the amplitude of accommodation in man

A single drop of phenylephrine 2.5% (MYDFRIN TM) was instilled into the eyes of 160 volunteers (aged 20 to 30 years) and their amplitude of accommodation assessed under standard illumination using a push‐up technique without an artificial pupil‐ The amplitude was assessed every 5 or 10 min over a period of 90 min. Within 30 min, nearly 75% of the subjects showed a measurable change in amplitude. Overall, the amplitude declined slowly with time to realize an average 11 % reduction from an average starting amplitude of 10.7 D. A large range of responses from a 30% increase to a 60% decrease in amplitude was. however, observed. Subjects with large amplitudes of accommodation were more likely to show significant decreases while some subjects with smaller amplitudes showed an apparent increase in accommodation (r2= 0.176). The phenomenon was observed in both blue‐ and brown‐eyed subjects and in non‐contact lens wearers and soft contact lens wearers (r2 values of 0.144 to 0.265).

A Review of the Clinical Pharmacokinetics of Pilocarpine, Moxisylyte (thymoxamine), and Dapiprazole in the Reversal of Diagnostic Pupillary Dilation

An alpha-adrenergic blocking drug, dapiprazole, is now marketed in eyedrop form. Dapiprazole is being promoted as an agent suitable for reversing the diagnostic mydriasis produced by tropicamide or tropicamide and phenylephrine. The mechanism of action of dapiprazole is thought to be the same as that of moxisylyte (thymoxamine). The human pharmacokinetics for these drugs are reviewed and compared to pilocarpine. Published data indicate that either dapiprazole (0.5%) or moxisylyte (0.5%) enhance recovery from the mydriasis produced by tropicamide, phenylephrine, or their combination. However, because the published studies differ substantially in the doses of these mydriatics or in the miotics actually used, it is not possible to make any firm recommendations on how many drops of these new miotics should be instilled.

Medications used to prevent migraine headaches and their potential ocular adverse effects.

We present a detailed review of the medications used in the USA, Canada, and the United Kingdom for the prevention of migraine and the potential ocular adverse effects associated with the use of these medications. Those drugs that are administered for the purpose of reducing the frequency or severity of migraine attacks are classified according to whether they act on the cerebral vasculature primarily at serotonin (5-HT2) receptors (e.g., methysergide, cyproheptadine, and pizotyline), beta adrenergic (primarily beta-2) receptors (e.g., propranolol and timolol), via central nervous system (CNS) adrenergic (alpha-2) receptors (e.g., clonidine), or calcium channels (e.g., flunarizine). The roles and mechanisms of action of tricyclic antidepressants (e.g., amitriptyline) and nonsteroidal anti-inflammatory drugs (NSAIDs) in the prophylactic management of migraine are also discussed, along with possible pharmacogenetic differences in the kinetics of action of some of these drugs. The general indications, contraindications, and potential ocular and systemic adverse effects of each class of drugs is reviewed and presented along with the references to original literature on these effects.

Granular corneal dystrophy: slitlamp biomicroscopic appearances in three generations of patients.

PURPOSE The purpose of this case series is to show photographically the varying clinical appearance of granular corneal dystrophy in three generations of one family and to review the genetic basis of this and related conditions. CASE SERIES We present cases for four affected individuals along with slitlamp biomicroscopic photographs. DISCUSSION A review of the photographs and the literature suggests that the abnormal keratoepithelin first appears in the superficial cornea as faint subepithelial opacities. With time, these become arranged in the curved lines of a vortex pattern, after which the deposits become scattered in no particular pattern and at all levels of the cornea. In this family, corneal erosions are a regular feature. Mutations of the gene coding for keratoepithelin (beta ig-h3) may give rise to variable clinical manifestations.Purpose.The purpose of this case series is to show photographically the varying clinical appearance of granular corneal dystrophy in three generations of one family and to review the genetic basis of this and related conditions. Case Series.We present cases for four affected individuals along with s

Viral hepatitis : a review

Viral hepatitis is neither a single disease condition nor is it caused by a single viral agent. Viral hepatitis can cause a wide spectrum of systemic manifestations. Here we concentrate on the five unrelated hepatitis viruses whose effect is limited almost entirely to the liver. More than 60,000 cases of viral hepatitis are reported to the U.S. Centers for Disease Control each year, although it is estimated that more than 300,000 cases actually occur. Some of the hepatitis viruses are present in all bodily fluids and, therefore, without adequate precautions, may be transmitted to either the health care provider or between patients in a clinical setting. The severity of an infection can be extremely variable among infections by the different virus types, as well as by a single virus type. Manifestations can range from the subclinical to the seriously acute to the chronic. In extreme cases, death can also result from infection, via such acute and chronic pathways as fulminant hepatitis, hepatocellular carcinoma, and cirrhosis of the liver. Because viral hepatitis is widely prevalent, can be transmissible in a clinical setting, and can have serious and long-lasting health consequences, all optometrists should be aware of some of the facts regarding viral hepatitis infections.

The Retinal Pigment Epithelium: Function and Disease

No wonder you activities are, reading will be always needed. It is not only to fulfil the duties that you need to finish in deadline time. Reading will encourage your mind and thoughts. Of course, reading will greatly develop your experiences about everything. Reading retinal pigment epithelium function and disease is also a way as one of the collective books that gives many advantages. The advantages are not only for you, but for the other peoples with those meaningful benefits.