A Custom-made Pupillometer System for Characterizing Pupillary Light Response

Objectives:This paper presents the design and construction of a viable pupillometer system and demonstrates its merits with extensive validation tests.Materials and Methods:A web camera was modified by removing its infrared filter and mounted on a chin rest. Light emitting diodes (LEDs) operating at infrared and visible spectra were integrated to provide background and light stimulus, respectively. The LEDs were controlled by a microprocessor board. Stimulation was presented using a periodic paradigm with variable period and duty cycle. Videos of both pupils were recorded at 30 frames/second and processed offline using software developed in-house. The overall system was validated with data gathered from individuals with healthy vision under different stimulation paradigms. Temporal variations in pupil size were determined and analyzed statistically.Results:The analysis revealed that the pupil sizes were accurately measured from the video frames provided that reflections from both infrared and visible lights remain outside the pupil. The system achieved moderate to excellent repeatability scores (87.8 and 86.8% for short 1 second and long 2 second pulses, respectively), which demonstrated its effectiveness and confirmed that it can be used reliably as a pupillometer.Conclusion:The proposed pupillometer system produces useful, quantitative data characterizing pupillary light response. However, further development and implementation are needed to potentially turn it into a low-cost alternative for other studies involving the autonomic nervous system, cognitive function, drug metabolism, pain response, psychology, fatigue, and sleep disorders

Medical control of intraocular pressure after phacoemulsification

Purpose: To compare the effectiveness of oral acetazolamide, topical brinzolamide 1%, and no ocular hypotensive medication after phacoemulsification. Setting: Adnan Menderes University Department of Ophthalmology, Aydin, Turkey

Colour Doppler Imaging of Superior Ophthalmic Vein in Thyroid-Associated Eye Disease

Purpose: One of the possible etiologies of proptosis in patients with thyroid-associated eye disease is stated to be passive orbital venous congestion caused by the occlusive and constrictive changes of the superior ophthalmic vein (SOV). In an attempt to clarify the validity of this claim, quantitative information on the flow velocity of the SOV was obtained by colour Doppler imaging in 24 patients with thyroid-associated eye disease and compared with data from the control group. Methods: On clinical examination, ocular motility, proptosis, soft tissue involvement, and the presence of optic neuropathy were evaluated. The interaction of these signs with the flow velocity of the SOV was investigated in conjunction with computed tomographic (CT) findings such as extraocular muscle enlargement, dilatation of the SOV, and apical crowding of the orbit. Results: The mean blood flow velocity was significantly decreased in patients compared to the control group ( P Ͻ .05). The CT measures that contributed to significant decreases in SOV blood flow velocity were apical crowding ( P Ͻ .05) and the coexistence of horizontal and vertical extraocular muscle involvement ( P Ͻ .05). Among the clinical measures, significant decreases could be attributed to soft tissue findings ( P Ͻ .01) and to optic neuropathy ( P Ͻ .05). Conclusions: External compression of the SOV may contribute to the SOV blood flow decrease in orbits afflicted with thyroid eye disease, but proptosis is not relevant to the SOV blood flow decrease. Jpn J Ophthalmol 2002;46:341-34

Effect of corneal drying on central corneal thickness

Purpose: To determine the amount of corneal thinning induced by corneal drying, and to discuss its possible consequences on applanation pressure