Use of teleoptometry to evaluate acceptability of rigid gas-permeable contact lens fits.

BACKGROUND: Teleoptometry involves the transmission of digitized optometric information from a remote site for analysis by an expert. This project assessed computer compression of video data showing contact lens fitting relationships and the transmission of these data to a specialist for evaluation METHODS: Fifty-five sets of video clips showing dynamic fluorescein patterns of rigid gas-permeable lens fits, topographic corneal maps, and basic information on lens parameters were evaluated-live and again after digitization and electronic compression-by a contact lens specialist. The evaluator was asked to determine whether lens fit was acceptable and, if not, how the lens parameters should be changed. RESULTS: Comparison of lens evaluations made live versus compressed showed agreement on fit acceptability for approximately 80% of the subject/lens combinations. When the evaluator concluded for both presentations that the lens was unacceptable, the same change in lens parameters was recommended 67% of the time. DISCUSSION: Agreement for the majority of live and compressed video observations suggests that teleoptometric consultation on contact lens fitting is feasible. When technology advances to the point at which large files can be sent quickly via the Internet, it is likely the practice of transmitting video clips and other information to obtain fitting assistance will become commonplace.

Implications of problem-based education for the future of optometric practice.

BACKGROUND: Optometry is changing from single-doctor, refraction-oriented practices toward group practices in which increasingly complex patient problems are managed. To prepare students for new modes of practice, the traditional lecture style of education is being supplemented with innovative techniques, such as problem-based learning (PBL). METHODS: Using PBL in a medical or optometric environment, a group of students would be given a complete case in the Subjective, Objective, Assessment, and Plan (SOAP) format. Then they would be asked to use the case as a basis for studying the underlying mechanism of the disease presented, the therapies available, why the management plan was selected, and why the patient responded as he or she did. RESULTS: Students work in groups to investigate the cases using on- and off-line resources. They set learning objectives for themselves and the group, and they evaluate each other's performances. A faculty member serves as a guide during this process. CONCLUSIONS: Students who complete a PBL course have not memorized a mountain of details as they would have in a traditional course, but have learned how to find and integrate information about patients, cases, diseases, etc. This enables them to deal with the exponential increase in knowledge that is occurring. In addition, by working together on PBL cases, students prepare themselves for group and other interactive practice environments.

Personal defense sprays: effects and management of exposure.

BACKGROUND: Most personal defense sprays contain o-chlorobenzylidene malononitrile (CS), w-chloroacetophenone (CN), oleoresin capsicum (OC), or a combination of these ingredients as the active agent. They are designed to incapacitate by causing acute ocular irritation, lacrimation, conjunctivitis, blepharospasm, and mild to moderate respiratory distress. METHODS: To assess the ocular effects of sprays containing OC as the active agent. Snellen visual acuities and anterior segment appearances of 22 police officers were determined before and after spray exposure. To assess the effects of OC spray contamination on soft contact lenses, four brands of lenses were sprayed and cleaned twice with an alcohol-based cleaner. Gas chromatography was used to search for residual OC in the lenses. RESULTS: All officers experienced intense blepharospasm, lacrimation, conjunctivitis, and incapacitation as the result of spray exposure. Acute effects lasted about 5 to 10 min, with relatively complete recovery occurring in about 30 to 60 min. All had significant conjunctivitis, and some had water-drop-shaped corneal defects that stained with fluorescein. These defects resolved within 24 hours without treatment. OC residue was found to be present in the soft lenses that had been sprayed and cleaned twice. CONCLUSIONS: Optometrists can manage uncomplicated spray exposure patients by directing at-home irrigation with water, and following up with an in-office examination. Soft lenses contaminated by OC spray should be discarded.

Myopia associated with hyperbaric oxygen therapy.

BACKGROUND: Hyperbaric oxygen therapy (HBOT) involves exposing patients to elevated oxygen pressures and concentrations for the treatment of soft tissue degenerative diseases. As side effects, some patients experience cataract development and/or a significant increase in myopia. SUBJECTS: Eight subjects participated in this project. All were receiving HBOT for health problems. METHODS: For all subjects, acuities and refractive error corrections were measured before and after HBOT sessions at the beginning, midpoint, and end of therapy. For four subjects, A-scan ultrasound and corneal curvature measurements were also made before and after selected HBOT sessions. In addition, susceptibility to free radical damage and indicators of actual damage were measured by blood analyses. During the first half of HBOT therapy, four subjects took placebo tablets; during the second half, antioxidant supplements were given. RESULTS: No subject showed significant acuity or refractive error changes produced by single HBOT sessions. Two of the 8 subjects showed significant increases in myopia over the 20 session course of HBOT. No corresponding changes were found in the ultrasound, corneal curvature, or blood analysis data. DISCUSSION: Theoretically, the increases in myopia could have been caused by lenticular refractive index changes resulting from oxidative damage to lens proteins. However, the biochemical assays used in this project did not predict which subjects were susceptible to increased myopia, nor did they demonstrate elevated levels of free radical activity in a subject who did experience an increase in myopia.

The effects of gender and birth control pill use on spontaneous blink rates.

BACKGROUND: Two major reference works suggest that men and women blink spontaneously at different rates, but they disagree with regard to which gender blinks faster. METHODS: Spontaneous blink rates of 59 males and 86 females, 44 of whom were taking birth control (BC) pills, were measured for 5 consecutive minutes. Schirmer test results and tear break-up times (TBUTs) were also obtained. RESULTS: Females taking BC pills blinked at a mean rate of 19.6 times per minute, females not taking birth control pills blinked 14.9 times per minute, and males blinked 14.5 times per minute. There were very large differences between blink rates for individuals in each of the groups. No strong associations were found between spontaneous blink rates and a history of contact lens use, tear break-up time, Schirmer test results, temperature or humidity in the examination room, subject age, or menstrual cycle phase. CONCLUSIONS: The 32 percent increase in mean blink rate for females taking BC pills suggests that the pills affect at least one of the mechanisms that control spontaneous blinking, but it is unclear how they accomplish this.

Free radicals and antioxidant supplementation: a review of their roles in age-related macular degeneration.

BACKGROUND: Age-related macular degeneration (ARMD) is a major cause of blindness in the elderly. Unfortunately, no proven form of treatment is currently available for the dry, atrophic form of ARMD seen in more than 90 percent of patients with this condition. METHODS: A recent theory suggests that ARMD is associated with damage to the retina caused by free radicals. If this is correct, it is possible that the damage could be prevented or moderated by supplementing the diet with specific antioxidant vitamins and minerals that enhance the body's natural defenses against free radicals. RESULTS AND CONCLUSION: This paper reviews the literature regarding the pathogenesis of ARMD and presents a rationale for its management or prevention by the use of supplemental vitamins and minerals.

Evaluation of dietary antioxidant levels and supplementation with ICAPS-Plus and Ocuvite.

BACKGROUND: Oxidative damage caused by free radicals has been implicated in the development of age-related macular degeneration (ARMD). Recent studies suggest that antioxidant vitamins and minerals can be useful for the management and/or prevention of this condition. METHODS: To assess the normal dietary intake of the antioxidants, 28 healthy subjects 55 years of age and over completed a diet survey. Then two over-the-counter (OTC) nutritional supplements that make claims about the antioxidant nutrients they contain (ICAPS-Plus and Ocuvite) were evaluated with respect to their ability to raise blood levels of two important antioxidant nutrients: zinc and beta-carotene. RESULTS: Based on the diet survey, 26 of the 28 subjects were found to have deficient intakes; zinc and selenium were the most commonly deficient nutrients. Following a 2-week administration period, both ICAPS-Plus and Ocuvite significantly raised mean serum zinc levels 24.7 percent and 18 percent respectively; ICAPS-Plus significantly raised mean beta-carotene levels by 21.4 percent, but Ocuvite did not change the mean level significantly. CONCLUSIONS: Based on the probable relationship between antioxidant levels and diseases such as ARMD, these results suggest that OTC supplements might be useful for selected patients.

New antibacterial drugs for topical ophthalmic use.

Three new antibacterial drugs have recently been approved for topical ophthalmic use. Ciprofloxacin (Ciloxan) and norfloxacin (Chibroxin) are fluoroquinolones with very broad activity spectra; both have been found to be safe and effective for the treatment of conjunctivitis. Ciprofloxacin, in the commercially available concentration (0.3%), has also been found to be a safe and effective treatment for corneal ulcers. Trimethoprim-polymyxin B (Polytrim) is a new combination product that has been used successfully for the treatment of conjunctivitis. Use of these three new drugs will significantly enhance the ability of the primary care clinician to treat bacterial infections of the cornea and conjunctiva.

Association of dry eye signs and symptoms with tear lactoferrin concentration.

Diagnoses of dry eye made with the Lactoplate Immunoassay Test (which assesses tear lactoferrin concentration) were compared to diagnoses based on dry eye symptoms, tear break-up times, and rose bengal staining. For a population of 49 subjects with normal and mild to moderate dry eyes, contingency tables showed that the lactoferrin-based diagnoses were not significantly related to the diagnoses made using any of the other factors. Lactoferrin concentrations were statistically correlated with symptom scores, but there was no significant correlation between lactoferrin concentrations and either tear break-up time or rose bengal staining. These results suggest that: 1) the dry eye problems in the subject population may not have been associated with lacrimal gland dysfunction (which the Lactoplate assesses); 2) Lactoplate tests are not sensitive enough to allow accurate diagnoses for the population of mild to moderate dry eye subjects used; 3) signs and symptoms associated with dry eyes occur before lactoferrin changes are manifest so lactoferrin changes had not yet appeared in the subjects; or 4) in mild to moderate dry eye subjects, lactoferrin changes occur only in reflexive tears and not in the basal tears that were tested in this study. In summary, measurement of tear lactoferrin concentration alone has not been shown to be a sufficiently sensitive and specific test for the diagnosis of mild to moderately dry eye as defined by more common clinical techniques.

Therapeutic pharmaceutical utilization by military optometrists.

The Air Force, Army, and Navy have instituted regulations that authorize optometrists to use therapeutic pharmaceutical agents (TPAs). A survey of clinical optometrists on active duty was conducted to evaluate the impact of these regulations on military optometry. The results indicate that the majority of optometrists support the regulations and are utilizing TPAs to treat a wide variety of ocular disorders. However, the survey also found a number of optometrists in each service who were dissatisfied with certain aspects of the regulations. Some Air Force and Navy optometrists expressed concern that their regulations did not allow access to TPAs which they felt qualified to use. Some Army respondents felt that their regulation was unduly influenced by local policy and was not an equitable means of granting therapeutic privileges. These concerns suggest that a reevaluation of the therapeutic regulations might be required in the future.

A comparison of diagnostic outcomes with and without pupillary dilatation.

To compare the quality of fundus evaluations conducted with natural and dilated pupils, 500 typical adult subjects, divided into five age categories, were examined using both techniques. Direct and monocular indirect ophthalmoscopes were used with the natural pupils; direct and binocular indirect scopes were used for the dilated examinations. Retinal anomalies were classified on the basis of posterior pole or peripheral location and whether the anomalies would require significant action by the doctor. Of the 32 posterior pole anomalies which required action, 38% were missed during the natural pupil examination; 51% of the anomalies not requiring immediate action were also missed. These miss rates, along with the 287 anomalies found in the periphery (20 of which required immediate action), suggest that dilation should be strongly considered for all patients so as to optimize the probability of detecting fundus anomalies.

Visual function and vitamin A/zinc nutriture in patients with complaints of night blindness.

Eighteen adults with night vision complaints showed significantly increased/final rod thresholds as compared to their age- and sex-matched controls. Vitamin A and zinc levels did not differ between the two groups. Vitamin A supplementation of three subjects produced changes in final rod thresholds and serum vitamin A levels. These changes did not produce subjective improvements in night vision.

Histocompatibility (HLA) antigens in keratoconus.

To determine if susceptibility to keratoconus is associated with the histocompatibility (HLA) system, we HLA-typed 39 keratoconic patients and 208 normal controls for 63 HLA-A, -B, and -C antigens. The antigen frequencies for the keratoconic patients did not differ significantly from the frequencies for the control patients. These results suggest that susceptibility to keratoconus is not associated with the HLA system.

Calcium: I. Ocular and systemic metabolism.

The research cited above has shown that calcium and related minerals play a significant role in the maintenance of ocular and systemic health. While it is difficult to obtain a complete picture of calcium metabolism in any given patient, the tests previously discussed (most of which can be performed by or at the direction of an optometrist) do serve to differentiate patients with normal versus aberrant calcium dynamics. Since calcium is important to the proper function of the visual system, the optometrist should be alert to signs and symptoms which can indicate calcium metabolic or nutriture imbalances, and test, counsel or refer suspect patients appropriately.

Calcium: II. Role in keratoconus.

Calcium metabolism was assessed in 18 keratoconic and 18 age- and sex-matched control subjects using four types of analyses: diet, serum, urine and hair. There was no significant difference between the two groups for dietary intake, serum, urine and hair parameters of calcium, and related minerals. Although the control group had a higher daily intake of vitamin D than did the keratoconus group, the serum levels of the active vitamin D hormone, 1,25-(OH)2 vitamin D3, were the same in both groups. These findings suggest that systemic calcium or vitamin D metabolic imbalances are not involved in maintaining eyes in a keratoconic state.

Nutritional effects of zinc on ocular and systemic physiology.

Zinc, an essential mineral in human nutrition, has multiple and complex ocular and systemic functions. Zinc deficiency is characterized by growth retardation, reduced appetite, skin changes, impaired reproductive development, impaired taste acuity, and impaired wound healing. Zinc deficiency may also cause or contribute to learning problems. Observations of Denver children have suggested that suboptimum zinc nutriture may be quite common in otherwise normal infants and children in the United States. The most likely cause of this deficiency is dietary insufficiency. High concentrations of zinc are found in human ocular tissues and are closely related to visual function. When zinc levels are inappropriately low, results can include ocular birth defects, reduced ability to dark adapt, excessively low IOP, and optic neuritis. Correction of zinc deficiency with zinc supplementation must be done cautiously because excessive zinc can interfere with the metabolism of copper and zinc.

Fluress, fluorescein and benoxinate: recovery from bacterial contamination.

The ability to recover from bacterial contaminations with Staphylococcus auresus and Pseudomonas aeruginosa was determined for three optometric DPAs: Fluress, fluorescein and benoxinate. Results show that Fluress recovers from contamination more rapidly than benoxinate or fluorescein. This ability to recover from contamination and the relative ease of use of Fluress may make it the DPA choice for a number of optometric procedures including applanation tonometry.

Diagnostic pharmaceutical agents: side effects encountered in a study of 15,000 applications.

Data on DPA side effects were gathered from six schools and colleges of optometry for a reporting period from February 1 to April 30, 1979. These data indicate a low incidence of mild and transient side effects caused by several of the DPAs.

Influence of certain indigenous gastrointestinal microorganisms on duodenal alkaline phosphatase in mice.

Alkaline phosphatase activity was assayed in duodenal homogenates or extracts from adult specific pathogen-free (SPF) and germfree mice and gnotobiotic mice monoassociated with a Lactobacillus sp., a Bacteroides sp., or a coliform strain indigenous to SPF mice. Activity levels of the enzyme were much higher in the preparations from germfree mice than in those from the SPF controls. In the gnotobiotes monoassociated either with a freshly isolated Lactobacillus sp. or a Bacteroides sp., the levels of alkaline phosphatase activity were intermediate between the values for germfree and SPF mice. By contrast, in the gnotobiotes monoassociated with a coliform strain, alkaline phosphatase activity remained at high germfree levels. Butanol extracts of duodenal tissue from SPF mice, germfree mice, and exgermfree mice associated with an indigenous microflora from SPF mice (conventionalized) were subjected to acrylamide gel electrophoresis. A stain for alkaline phosphatase activity revealed three major bands in the gels prepared with extracts from SPF and conventionalized mice, but only two in the gels prepared with extracts from germfree mice. All three bands may have been present in the latter gels. One of the bands (the middle one) may have been obscured, however, by high activity in the slowest moving band. As determined by densitometric scanning, the slowest moving band had much higher activity in the preparations from germfree animals than in those from SPF or conventionalized mice. These findings suggest that the indigenous microbial flora affects not only quantitatively, but also qualitatively, the activity of alkaline phosphatases in the mouse intestinal mucosa.

Influence of the indigenous gastrointestinal microbial flora on duodenal Mg2+ -dependent and (Na+ + K+) -stimulated adenosine triphosphatase activities in mice.

Mg-dependent and (Na+ + K+)-stimulated adenosine triphosphatase (ATP-ase) activities were assayed in butanol extracts of duodenal tissue from germ-free, specific-pathogen-free, and ex-germfree mice associated with an indigenous microflora from specific-pathogen-free mice. In the germfree mice the levels of both ATPase activities were significantly higher than the levels in specific-pathogen-free mice. By contrast, the ex-germfree animals colonized by an entire indigenous microflora, the values fell to levels close to those for specific-pathogen-free animals. (Na+ + K+)-stimulated ATPase was not inhibited by ouabain in extracts from any of the three kinds of mice. These findings show that the indigenous microbial flora influences the intestinal ATPase activity of mice and, because of the connection between (Na+ + K+-stimulate ATPase and active transpoort, undoubtedly affects the process of absorption in the intestinal tract.