The role of anterior segment optical coherence tomography in the evaluation of the pterygium.

BACKGROUND: To evaluate the ability of anterior segment optical coherence tomography (AS-OCT) to visualize the anatomic features of the pterygium and its invasion of the corneal layers. METHODS: Seventy-five eyes of 54 patients diagnosed with pterygium were included. All subjects underwent complete ophthalmologic examinations, including AS-OCT. The limbus-apex distance, vertical height at the limbus, invasion of the Bowman's and stromal layers, and other morphologic structures of the pterygium tissue were analyzed. RESULTS: The mean age of the patients was 49.67 ± 16.49 (20-85) years. The mean apex-limbus distance was 2548.37 ± 1026.32 (933-4597) µm, and the mean vertical height at the limbus was 4843.89 ± 1374.10 (1740-7784) µm. A space was observed beneath the pterygium tissue in 44 (58.67%) eyes. The mean width and height of this space were 1756.33 ± 560.22 (1009-3095) µm and 231.70 ± 85.88 (109-465) µm, respectively. Invasion of the Bowman's layer was apparent in 74 (98.67%) eyes, and invasion of the stromal layer was detected in 33 (44%) eyes. A hyperreflective layer was observed beneath the epithelial layer at the edge of the pterygium apex in 31 (41.33%) eyes. In 24 (92.31%) of the 26 advanced pterygium cases and 20 (40.82%) of the 49 early pterygium cases, a subpterygium space was found beneath the lesion (p = 0.0001). CONCLUSION: AS-OCT enables measurement of the actual size and thickness of pterygia, assessment of invasion of the Bowman's and stromal layers of the cornea, and evaluation of the pterygium structure. Over half of the eyes exhibited space beneath the pterygium.

Ability of non-invasive tear break-up time to determine tear instability in contact lens wearers.

PURPOSE: To evaluate the performance of precorneal and prelens non-invasive tear break-up time (NIBUT) measurements to determine tear instability in contact lens (CL) wearers. METHODS: In this study, 50 eyes of 25 CL wearers were evaluated. Precorneal first and average NIBUTs and fluorescein tear break-up time (FBUT) were measured before wearing CLs in the morning. Those with FBUT less than 10 s were considered to have tear instability. After wearing CL, first and average prelens NIBUTs were measured at the 30th minute. The receiver operating characteristic (ROC) curve was analyzed to evaluate the performance of NIBUT measurements in the diagnosis of tear instability. RESULTS: The FBUT value had a significant correlation with first and average precorneal NIBUT values (p < 0.001, r = 0.653 and p < 0.001, r = 0.628, respectively). The FBUT value had no correlation with the prelens first and average NIBUT values (p = 0.542 and p = 0.263, respectively). To understand the relationship between the precorneal and prelens NIBUT values measured by the automated method, their correlation was evaluated. There was no significant correlation between the precorneal and prelens NIBUTs (for all; p > 0.05). The area under curve (AUC) in ROC curve for the first and average precorneal NIBUTs were 0.842 (p < 0.001) and 0.810 (p < 0.001), respectively. The AUC values for the first and average prelens NIBUTs at the 30th minute of CL wear were 0.586 and 0.619, respectively (p = 0.317 and p = 0.166, respectively). CONCLUSIONS: Precorneal NIBUT measurements may be useful in diagnosing tear instability. Prelens NIBUT values are not yet capable of adequately defining the tear film dynamics in CL wearers.

Static and dynamic pupillary characteristics in multiple sclerosis.

PURPOSE: To examine the static and dynamic pupillary functions with automated pupillography in multiple sclerosis (MS) patients with preserved visual acuity. METHODS: Forty-seven MS patients with preserved visual acuity were included in the study group and 43 healthy volunteers in the control group. The visual evoked potential of the patients was obtained. After routine ophthalmologic examination contrast sensitivity and the retinal nerve fiber layer (RNFL) thickness were measured. Finally scotopic, mesopic, and photopic pupillographies followed by dynamic pupillography were undertaken, and the pupillary dilatation speed was calculated. RESULTS: The contrast sensitivity and RNFL thickness of the MS group were significantly lower than those of the control group (p < 0.05; for both). In the MS and control groups, the scotopic pupil diameters were 5.48 ± 1.03 and 5.28 ± 0.78 mm, mesopic pupil diameters were 4.82 ± 0.83 and 4.48 ± 0.70 mm, and photopic pupil diameters were 3.84 ± 0.79 and 3.42 ± 0.49 mm, respectively (p = 0.315, p = 0.044, and p = 0.004, respectively). In dynamic pupillography, the pupil in the MS group was more dilated than control group at all time sections examined except the sixth second (p < 0.05; for all). Although the mean pupillary dilation speed in the first second was higher in the MS group (p = 0.044), there was no significant difference between the groups for the other time intervals examined (p > 0.05; for all). There was no correlation between pupillary parameters and P100-wave latency, RNFL thickness, or contrast sensitivity (p > 0.05; for all). CONCLUSIONS: Static and dynamic pupillary functions may be affected in MS patients with preserved visual acuity. Although scotopic pupillary functions are preserved, mesopic, and photopic pupil functions are weakened.

Performance of a photoscreener in detecting accommodation spasm.

CLINICAL RELEVANCE: For a correct spectacle prescription, accommodation spasm should not be overlooked in the measurements made using an autorefractometer. Although this can be easily understood with cycloplegia, it is not practical. Therefore, investigating practical methods that can predict excess accommodation will be useful in clinical practice. BACKGROUND: To evaluate the performance of a photoscreener in detecting pseudo-myopia due to accommodation spasm and whether it eliminates the need for cycloplegia. METHODS: Study was conducted in Van Training and Research Hospital. The manifest refraction of the patients was measured using an by an autorefractometer followed by a photoscreener before cycloplegia. Cycloplegic refraction errors were detected using an autorefractometer. Patients with pseudo-myopia due to accommodation spasm were diagnosed by observing a significant hyperopic shift in cycloplegic autorefractometer values compared to the non-cycloplegic values and were included in study. Cycloplegic autorefractometer and non-cycloplegic photoscreener measurements were compared. RESULTS: The mean non-cycloplegic autorefractometer values were as follows: --6.34 ± 1.29D, -0.42 ± 0.58D, and -6.55 ± 1.36D for spherical, cylindrical, and spherical equivalents, respectively. These values were 0.23 ± 0.63D, -0.21 ± 0.41D, and 0.11 ± 0.73D for cycloplegic autorefractometer measurements, respectively. Cycloplegic autorefractometer values showed a significant hyperopic shift of 6.57 ± 1.26D and 6.67 ± 1.34D for spherical and spherical equivalents, respectively, compared to non-cycloplegic values (p < 0.001 for both). There was no significant difference between non-cycloplegic photoscreener and cycloplegic autorefractometer measurements for spherical, cylindrical, and spherical equivalents (p = 0.126, p = 0.078, and p = 0.053, respectively). . There was agreement between the measurements in the Bland-Altman graph. CONCLUSION: There was consistency between non-cycloplegic photoscreener and cycloplegic autorefractometer measurements in patients with pseudomyopia due to accommodation spasm. Therefore, photoscreener measurements can be a fast, practical, cost-effective examination method for screening these patients without the need for cycloplegia.