vol. 10 núm. 1 (2012)

Fitting scleral lens in management of keratoconus can be a good alternative. Objectives: To compare the adaptation of rigid gas permeable scleral lens in patients with keratoconus, mathematically calculated based on data from visante oct (optical tomography coherence) and the traditional method (trial and error). Materials and methods: Descriptive observational research was carried out. Rigid scleral contact lenses were adapted to eight patients (16 eyes) diagnosed with keratoconus, using two calculation methods: the traditional trial and error and calculating the parameters of the lens using a mathematical model, based on the topography data and the high-resolution ct with visante oct. With each method, the visual acuity was evaluated, as well as the number of tests needed for the final adaptation, the comfort and the ocular surface. Results: Visual acuity was the same in both methods and the assessment of the ocular surface presented statistical differences (p < 0.05 according to the Wilcoxon rank test) and clinically significant, where the method of mathematicalmodeling was better; likewise, the method of mathematical modeling achieved better comfort and a lower number of tests than the traditional. Conclusions: Using current technology can contribute to improve scleral lenses adaptation and to optimize time and resources.

Pterygium is a conjunctival fibrovascular tissue growth extending over the cornea. It may exceedthe pupil area, interfere with vision and generate traction that could cause refractive changes.<em><strong>Objective:</strong></em> To determine changes in visual acuity in keratometry and the refractive state after mildto moderate pterygium surgery. <em><strong>Materials and Methods:</strong></em> Descriptive observational study in which52 eyes of 46 patients who were diagnosed with grade i or grade ii pterygium were evaluated atthe San Antonio Hospital in Chia. Each patient’s visual acuity, keratometry and refraction wasmeasured before and one month after pterygium surgery. The ji2 (c2), t paired and Wilcoxon testswere performed. <em><strong>Results:</strong></em> The group with grade i pterygium showed no statistically or clinicallysignificant differences in visual acuity (p = 0.14), or keratometry (p = 0.69) or refraction (p = 0.33)after surgery. The group with grade ii pterygium showed statistically significant differences inkeratometry (p = 0.0042), but not in visual acuity (p = 0.88) or in refraction (p = 0.52), but thesepatients showed a trend to diminish their vision with a tendency to be more myopic. <em><strong>Conclusions:</strong></em> No significant changes were seen after surgery in the patient group with grade i pterygium, whilethe group with pterygium grade ii saw a statistically significant change in keratometry and clinicallyrelevant changes in visual acuity without correction. Therefore the present study suggeststhat the optical prescription of the patient must be given after the post surgical period.

The contrast sensitivity tests (cs) are a powerful toll for determining the vision capability. It isimportant to know the development of this function and have precise parameters for the earlydiagnosis of abnormalities. <em><strong>Objective:</strong></em> To determine normal values for sc with the FunctionalAcuity Contrast Test (fact) in children between four and seven years in the locality of Chapineroin Bogota. <em><strong>Materials and methods:</strong></em> An observational cross sectional study was performed with 280eyes. They were classified into two groups: Group 1, four to five years of age, and group 2, sixto seven years of age, valuing contrast with fact for the different spatial frequencies. <em><strong>Results:</strong></em> csvalues were determined with the average, interquartile range and the statistical test U from MannWhitney, which revealed no significant differences for any of the spatial frequencies. The normalrange found for frequency A were between six and seven; for frequency B, between five and seven;for frequency C, between five and seven; for the frequency D, between four and seven; and forthe frequency D, between five and seven. Comparing the ranges for both groups, there were nostatistically significant differences in most frequencies. <em><strong>Conclusions:</strong></em> The range and average foreach of the frequencies were within expected ranges for the test; it was observed that there weredifferences in the development of cs between groups A and B, with a wider amplitude for the oldest.

Dry cleaning workers are exposed to organic solvents like perchlorethylene (perc). This can affect the Central Nervous System (cns), provoke neurotoxicity and associate to neuro-visual alterations related to the visual contrast sensitivity function (csf) and the loss of color vision. Objective: To determine the deficits of contrast sensitivity (csf) by spatial frequency in a group of dry cleaning workers exposed to occupational levels of perc and its relation to the neurotoxic symptoms. Materials and methods: A case and control study in 40 dry cleaning workers and in 35 regular people with no exposure to perc was done in Bogota, Colombia. The csf was evaluated using psychophysical methods; the spatial frequencies studied were 0.5, 1.0, 2.0, 4.0, 8.0 and 16.0 cpd. Neurotoxicity was evaluated with the modified questionnaire Q16. Results: Significant differences were observed in cs above 1.0cpd (p < 0.05). The Spearman correlation showed a significant negative relation between the punctuation of the modified version of the Q16 questionnaire and the spatial frequencies2.0, 4.0 and 8 cpd (Spearmanp Rho < 0.05) in the cases. The Mann Whitney U test showed significant differences between cases and controls for the modified Q16 questionnaire (p <0.05). Conclusion: the csf was significantly lower in those exposed to perc for the spatial frequencies above 1.0 cpd. The presence of neurotoxic symptoms in dry cleaning workers is associated with losses in csf in medium and high spatial frequencies.

The ocular surface damage associated with the alteration of the tear film causes multiple symptoms, and autologous serum is used as treatment. Objectives: To compare the effect of autologous serum on the ocular surface repair, prepared with two different concentrations (80 y 20 %). Materials and methods: A quasi-experimental prospective study was carried out in 25 patients diagnosed with dry eye through the Schirmer test, tbut and Rose Bengal staining. Autologous serum eye drops wereadministered to 80% in the right eye and 20% in the left eye, and after 30 days of application, tests were once again performed. For the preparation of autologous serum, ethical procedures were performed and the standardized protocol at the University of Lübeck, Germany, was followed according to the Bundesärztekammer guide and the Paul Ehrlich Institute. Results: The application of autologous serum to 80% and 20% showed a significant increase in both tear volume (Schirmer)and tear stability and quality (tbut) and, additionally, ocular surface repair is achieved. No significant differences were found with the two concentrations but with higher concentrations a greater effect on production and time of rupture of the tear film is achieved (p<0.080). Conclusions: The administration of autologous serum as a treatment for dry eye presents repair on the ocular surface in both concentrations of 80% and 20%.

In this paper, we present three applications of the Hartmann test in vision science, developed atthe optical design laboratory of the Physics Department at the National University of Colombia:lensmeter for progressive addition lenses, corneal topography, and Hartmann-Shack aberrometer.First we briefly describe the classical Hartmann test for astronomical mirrors, and later threevariations of the Hartmann test for optometry and ophthalmology are done. In each case the opticalsystem and geometry used to derive the wavefront aberration from ray aberrations (Hartmannpatterns) are described. In all three cases similar mathematical relationships are obtained, so thatthe wavefront can be determined in each case using the same method of integration. Afterwards,the quantities of interest are calculated in order to find out: in lensometry, maps of cylindrical andspherical refractive power; in topography, the map of tangential curvature; and in aberrometry,the wavefront elevation map and psf. Finally, a brief comment is made on the implementationof the Hartmann test by some commercial companies.

<em><strong>Objective:</strong></em> To determine the prevalence of impaired color vision and visual motor dysfunctionin a group of children aged between five and fifteen years in the localities of Fontibon, PuenteAranda and Usaquén in Bogota. <em><strong><em><strong>Methodology:</strong></em></strong></em> We conducted a descriptive study in 243 patientswho were studying in schools representing each locality. Each child was subjected to the Ishiharaand Farnsworth tests of visual-motor integration (vmi). Statistical analysis was performed usingcontingency tables and ji2 (c2). <em><strong><em><strong>Results:</strong></em></strong></em> The prevalence of impairments in color vision was 6.7%(6/89 Ishihara test) and 14.6% (13/89 Farnsworth test) for the Spanish school in Puente Aranda, 2.4% (2/84 Ishihara test) and 4.8% (4/84 Farnsworth test) for the Pablo Neruda school in Fontibón,and 2.9% (2/70 Ishihara test) and 10% (7 / 70 Farnsworth test) for the La Salle School in Usaquén.The prevalence of visual-motor dysfunction was 55.1% (49/89) for the Spanish school in PuenteAranda, 28.6% (24/84) for the Pablo Neruda school in Fontibón, and 18.6% (13/70) for the LaSalle School in Usaquén. <em><strong>Conclusions:</strong></em> The prevalence of impaired color vision and visual motordysfunction was higher in the villages of Puente Aranda and Fontibon than in the town of Usaquén.

Antihistamines such as epinastine hydrochloride have anti-inflammatory activity and could be used as a treatment for dry eye syndrome. Objective: To assess changes in symptoms, tear film and ocular surface before and after treatment with epinastine hydrochloride in patients with dry eye syndrome. Materials and methods: A double-blind pilot study was carried out in 20 patients with clinical diagnosis of moderate dry eye. One eye of each patient was treated with 0.05% ofepinastine hydrochloride and the other received 0.4% of sodium hyaluronate. Both eyes received tear supplement with 0.4% of sodium hyaluronate. The treatment dose was one drop three times a day for 45 days. Before treatment and 30 and 45 days after, the validated questionnaire for dry eye (osdi), the Schirmer 1 Test, but and lissamine green were used. The Student’s t test and Wilcoxon ranges were used. Results: A statistically significant improvement in symptoms after 30 days of the intervention with epinastine was found (p = 0.000) and after 45 days (p = 0.0000). In the ocular surface there was clinically and statistically significant improvement after 45 days (p = 0.0001). No significant changes were found in quality or quantity of the tear film. The reduction in symptoms and in the degree of staining with epinastine after 45 days was statistically significant (p < 0.05) compared with the control group. Conclusion: The combination of epinastinehydrochloride 0.05% and sodium hyaluronate 0.4% improves symptoms and the ocular surface in patients with moderate dry eye.

<em><strong>Objective:</strong></em> To identify whether there are significant variations in the degree of higher-order corneal aberrations after implantation of intrastromal rings in patients diagnosed with corneal ectasia. <em><strong>Materials and methods:</strong></em> An analytical and longitudinal study of intervention in patients over 18 years was carried out. The refractive state was evaluated, as well as the visual acuity measured by logmar; the topographic keratometry, the corneal optical aberrations coma, the trifoid, the spherical and the Root Mean Square High Order (rms Ho), by the Keratron Scout topograph, and the visual quality through Mars letters test for contrast sensitivity. All of this was done in three times before surgery, first and third post-op months. Results: In 39 eyes of 26 patients evaluated before, after one and three months after the implantation, clinical differences were significant, though not statistical: a) visual acuity was increased with no correction, b) there was a decrease in spherical and cylindrical values, c) flattening in K1 and K2, d) differences in the degree of high order optical aberrations of cornea after the procedure, e) a better visual quality for these patients and f) use of ophthalmic lenses with a greater tolerance. <em><strong>Conclusion:</strong></em> The optical aberrations of the anterior surface of the cornea do not have a statistically significant difference before or after the implantation of intrastromal segments, although there are changes at a clinical level and in magnitude.

<em><strong>Objective:</strong></em> To develop an epidemiological baseline and find out the socioeconomic conditions andmorbidity of patients seen in the optometric practice in areas of Tolima where the final semesterinternship of students from the program of Optometry, Faculty of Science Health at the Universityof La Salle in 2010 was carried out. The study is observational and descriptive. Those reported inthe rips of each institution in 2010 who attended the optometric practice in the teaching-serviceagreement in the extension Optometry program of the University of La Salle were taken as thetarget population. <em><strong>Materials and methods:</strong></em> The data collection technique used was observation andthe data collection instrument was the rips form. Also, a survey of users and the community wastaken to determine the socioeconomic conditions within the population. For the determination ofvisual morbidity, information reported by each institution in the 2010 rips was sampled. <em><strong>Results:</strong></em>We found that visual defects affected more than eye problems. Astigmatism and farsightedness arethe defects with the highest incidence in the population studied. The population does not havea healthy lifestyle, which presents risk factors that increase the likelihood of contracting diseasesthat not only affect eye health, but also systemic health.

<em><strong>Objective:</strong></em> To determine the behavior in corneal thickness during 30 days using high and low lens transmissibility (Dk/t). <em><strong>Materials and methods:</strong></em> 26 eyes of 13 non contact lens wearers were studied. On the right eye, a high Dk lens was adapted, lotrafilcon A and in the left eye a low Dk lens, vasurfilcon A, for 30 days in daily use. Before adaptation, the corneal thickness was measured with the Oculus Pentacam, the test was repeated on the first day within 4 and 8 hours and then within 3, 8, 15, 20, 25 and 30 days. In each control, the corneal thickness was measured after 6 hours of use. The Anova test was used, as well as the Student’s t test and the Pearson correlation coefficient. <em><strong>Results:</strong></em> During daily use for 30 days with lotrafilcon A, significant differences (p<0.05) in edema (0.76 ± 2.05 %) were found within 8 days of use. With vasurfilcon A, increment occurred after 4 hours of use, being statistically significant (p<0.05), edema (1.27 ± 1.64) within 3 days of use. anova showed significant differences (p<0.05) in the percentage of edema during the month ofuse of each type of lens, but not in the intergroup variance (p>0.05). <em><strong>Conclusion:</strong></em> The lotrafilcon A and vasurfilcon A lenses in daily use did not induce significant changes in corneal thickness, with edemas lower than 2 %.

Presbyopic visual comfort has improved considerably with the evolution in the design and manufactureof progressive lenses. Adapting to these immediately requires a proper choice of progressivelens and making accurate measurements, which the I-Terminal allows. <em><strong>Objective:</strong></em> To evaluate thesixth-generation progressive lens fitting for presbyopic patients who have worn traditional bifocallens for over two years, using the I-terminal for taking measurements. <em><strong>Method:</strong></em> A descriptiveobservational study with a sample of 20 patients who have used bifocals for over two years. Thecomputer-I-Terminal Carl Zeiss Vision house was used for taking measurements of the adaptationto progressive lenses. The adaptation was evaluated using the survey afa2’q y afa4q. <em><strong>Results:</strong></em> Wefound that 100% of the patients had an immediate adaptation to progressive lenses. <em><strong>Conclusion:</strong></em> There was an immediate adaptation to progressive lenses and taking measurements with the ITerminal.Also, in assessing vision and comfort, it was demonstrated that patients using bifocalsfor a long time are good candidates for progressive lenses.

The reason for the discomfort in presbyopic patients may be due to dysfunction in the skills ofconvergence, which may not efficiently compensate for the phoric position in near vision. <em><strong>Objective:</strong></em> To determine the impact of visual training in the ranges of convergences of presbyopicpatients. <em><strong>Materials and methods:</strong></em> 54 subjects with presbyopic correction. Groups of 27 patientswere formed. The intervention group underwent a convergence training program for ten weeks.Negative and positive convergence fusions, the accommodation-convergence ratio, the distancein centimeters from the next point of convergence and lateral and vertical phorias for near visionwere measured using the Von Graefe method and the degree of visual discomfort. <em><strong>Results:</strong></em> Thestudent test confirmed that there is significance (p <0.005) in the intervention group between: a)the value of the initial discomfort and the final value, and b) the values of breakdown and recoveryof the positive convergence. The mean values of rupture were 19.70 prism diopters initially, and26.07 at the end, and 4.48 to 13.33 prism diopters in the recovery. The value of the near point ofconvergence measured in the initial intervention group was 15.63 centimeters and in at the endit was 6.28 centimeters. The variation in initial and final AC/A measurement of the interventiongroup was 1.1 prism diopters. <em><strong>Conclusions:</strong></em> The visual training has a positive impact on convergences,normalizes the near point of convergence and reduces visual discomfort.

The assessment of visual acuity in school children is done using eye charts. The most used inclinical practice are Snellen and Bailey Lovie. The way they evaluate vision in children doesnot differ much from the way it is done with adults. However, when selecting the test, cognitivedevelopment must be taken into account. Objective: To determine the correlation between theSnellen numbers test and Lea numbers test in children between four and seven years of age inBogota. Materials and methods: The sample was chosen for convenience. We evaluated 169 visuallyhealthy children (331 eyes), aged between four and seven years, in the schools of the Institutode Bienestar Familiar, Bogota Optometry Clinic schools, and University of La Salle, between Mayand August 2011. Visual acuity (av) was assessed with a Snellen numbers chart and Lea numberschart with a Bailley Lovie type design. A Spearman test was used to determine the correlationbetween the two charts. Results: Results of the Spearman correlation test found a correlation of0.462 between both tests - moderate but statistically significant. With the Mann-Whitney test asignificant difference between measurements with both av tests was found. Conclusions: Snellenand Lea tests are different and, therefore, not interchangeable.