Précis: The C3 fields analyzer (CFA) is a moderately reliable perimeter preferred by patients to standard perimetry. While it does not approximate the gold standard, it was sensitive and specific for clinically defined glaucoma (area under the receiving operator characteristic curve=0.77 to 0.86). Purpose: Testing the visual field is a vital sign for diagnosing and managing glaucoma. The current gold standard, the Humphrey visual field analyzer (HFA), is large, expensive and can be uncomfortable for some patients. The current study investigated the CFA, a virtual reality head-mounted visual field testing device, as a possible subjective field test for glaucoma screening and eventually glaucoma monitoring. Patients and Methods: The CFA presented stimuli in the same 54 positions as the HFA 24-2 SITA Standard test using a suprathreshold algorithm approximating an 18 dB deficit. A total of 157 patients (both controls and glaucoma patients) at the Aravind Eye Hospital, Pondicherry, India, were tested with both devices. Results: The number of stimuli missed on the CFA correlated with HFA mean deviation (r=0.62, P<0.001), and with pattern standard deviation (r=0.36, P<0.001). The area under the receiving operator characteristic curve was 0.77±0.06 for mild glaucoma (HFA mean deviation ≥−6 dB) and 0.86±0.04 for moderate-advanced glaucoma (HFA mean deviation <−6 dB). Patients with an 18 dB or worse deficit at a point in the visual field on the HFA failed to see the CFA stimulus at the same position 38% of the time. Conclusions: While the CFA did not reliably identify deficits that matched the HFA, it was moderately effective at identifying glaucoma subjects. Further refinements to the device will be required to improve point by point testing performance and screening performance.

Good optical quality single crystal of L-histidine hydrochloride monohydrate (LHC) a novel semi organic NLO material was grown by slow solvent evaporation technique. The crystal was characterized by X-ray diffractometry (XRD), Fourier Transform Infra-red (FTIR), UV-Vis-NIR, TGA, DTA, microhardness and solubility studies. The SHG efficiency is found to be higher than that of KDP crystal. The dielectric constant and dielectric loss of the crystal was studied as function of frequency and the results are discussed. Photoconductivity studies were also carried out which reveals the positive photoconducting properties of the sample.

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The growth of a novel organometallic nonlinear optical (NLO) crystal of thiourea complex bis(thiourea) cadmium formate (BTCF) in larger size is reported for the first time by the slow evaporation method. The grown crystal was subjected to single-crystal X-ray diffraction, morphology, optical transmission, Fourier transform infrared (FT-IR) spectroscopy, second harmonic generation (SHG) efficiency test and microhardness studies. The powder SHG efficiency of BTCF is comparable with KDP.

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