Corneal Sensitivity and Dry Eye Symptoms in Patients with Keratoconus.

PURPOSE: To investigate corneal sensitivity to selective mechanical, chemical, and thermal stimulation and to evaluate their relation to dry eye symptoms in patients with keratoconus. METHODS: Corneal sensitivity to mechanical, chemical, and thermal thresholds were determined using a gas esthesiometer in 19 patients with keratoconus (KC group) and in 20 age-matched healthy subjects (control group). Tear film dynamics was assessed by Schirmer I test and by the non-invasive tear film breakup time (NI-BUT). All eyes were examined with a rotating Scheimpflug camera to assess keratoconus severity. RESULTS: KC patients had significatly decreased tear secretion and significantly higher ocular surface disease index (OSDI) scores compared to controls (5.3+/-2.2 vs. 13.2+/-2.0 mm and 26.8+/-15.8 vs. 8.1+/-2.3; p0.05). The mean threshold for selective mechanical (KC: 139.2+/-25.8 vs. control: 109.1+/-24.0 ml/min), chemical (KC: 39.4+/-3.9 vs. control: 35.2+/-1.9%CO2), heat (KC: 0.91+/-0.32 vs. control: 0.54+/-0.26 Delta degrees C) and cold (KC: 1.28+/-0.27 vs. control: 0.98+/-0.25 Delta degrees C) stimulation in the KC patients were significantly higher than in the control subjects (p0.05), whereas in the control subjects both mechanical (r = 0.52, p = 0.02), chemical (r = 0.47, p = 0.04), heat (r = 0.26, p = 0.04) and cold threshold (r = 0.40, p = 0.03) increased with age. In the KC group, neither corneal thickness nor tear flow, NI-BUT or OSDI correlated significantly with mechanical, chemical, heat or cold thresholds (p>0.05 for all variables). CONCLUSIONS: Corneal sensitivity to different types of stimuli is decreased in patients with keratoconus independently of age and disease severity. The reduction of the sensory input from corneal nerves may contribute to the onset of unpleasant sensations in these patients and might lead to the impaired tear film dynamics

The reliability of grading the fixation preference test for the assessment of interocular visual acuity differences in patients with strabismus

Mocan, Mehmet Cem/0000-0002-3419-9105WOS: 000176344100011PubMed: 12075297Purpose: The purpose of this study is to test the reliability of the grading system of standard fixation preference testing compared with the logarithmic scale of the minimum angle of resolution (logMAR) interocular visual acuity difference of patients with manifest strabismus and to test the strength of association between the interocular visual acuity difference and the grade of alternation. Methods: A total of 111 strabismic patients with large angle heterotropias (> 10 PD) were included in this study. The visual acuities of these patients were determined using the Snellen's, tumbling E, or Lea visual acuity charts as appropriate for the child's age and ability to cooperate. The results were converted to their logarithmic equivalents of minimum angle of resolution or recognition. Fixation preference was graded from 0 to 4 and was evaluated by observing the time-period through which fixation was maintained with the nonpreferred eye. Results: The median value of interocular visual acuity difference for grade 4 was determined as 0.0, grade 3 as 0.097, grade 2 as 0.17, grade 1 as 0.3, and grade 0 as 0.8. The grade of fixation preference was found to be inversely related to the logMAR interocular visual acuity difference (P < .0001). There was a significant difference between every fixation grade except grade 1 and grade 2 (P < .005). Conclusions. The grades used in fixation preference testing correlate with the logMAR visual acuity differences in strabismic amblyopic patients. However, the grading system does not imply a linear function in terms of visual acuity difference. The difference between the logMAR values of patients with grade 0 and 1 are more profound compared with other grades

In Vivo Confocal Microscopic Evaluation Of Keratic Precipitates And Endothelial Morphology In Fuchs' Uveitis Syndrome

Purpose To evaluate the endothelial cell layer in patients with Fuchs' uveitis syndrome (FUS) with respect to the type and distribution of keratic precipitates (KP), endothelial cell morphology, and endothelial cell density (ECD), using in vivo confocal microscopy (IVCM). Methods Forty eyes of 40 patients (mean age of 32.2 +/- 12.5 years) with the clinical diagnosis of FUS were evaluated with IVCM (Confoscan 3.0, Vigonza, Italy). KP were classified as type I (small, round), type II (stippled), type III (dendritiform), and type IV (globular). When >1 KP type was present, differentiation between the predominant and less frequent KP was made as 'primary' and 'secondary'. ECD was measured and compared with age-matched 60 control subjects. Endothelial blebs were classified as small (3-10 mu m) or large (> 10 mu m). Results In 36 (90.0%) cases with FUS, more than one KP type was observed with IVCM. Type III (dendritiform) KP was the most frequently observed primary KP type (85.0%), followed by type II (stippled) KP (15.0%). Secondary KP included type 11 (58.3%), type IV (globular) (27.8%), and type III (13.9%). The mean endothelial cell density of eyes with FUS (2588 +/- 396 cells/mm(2)) was significantly lower than that of control subjects (2930 +/- 364 cells/mm(2)) (t-test; P < 0.001). Eyes with FUS had lower proportion of hexagonal cells and higher percentage of polymegethism compared with the uninvolved contralateral eyes. Endothelial blebs (21 small, 16 large blebs) were observed in 37 (92.5%) eyes. Conclusions FUS is characterized by dendritiform KP and is associated with decreased ECD and altered endothelial cell morphology. Eye (2012) 26, 119-125; doi:10.1038/eye.2011.268; published online 4 November 2011WoSScopu