Two-Photon Microperimetry: A Media Opacity-Independent Retinal Function Assay

Purpose

Compare results obtained using infrared two-photon microperimetry (2PM-IR) with conventional visual function tests in healthy subjects of varying ages with and without simulated media opacities.

Methods

Subjects from two separate cohort studies completed cone contrast threshold (CCT) testing, conventional microperimetry, visible light microperimetry from a novel device (2PM-Vis), and infrared two-photon microperimetry. The first cohort study, which consisted of six healthy volunteers (23 to 29 years of age), evaluated the effects of simulated media opacities on visual performance testing. Subjects underwent testing on four visual function devices nine separate times under the following conditions: no filter, red filter, green filter, blue filter, light brown filter, dark brown filter, polarized black filter (0° rotation), and polarized black filter (90° rotation). Subjects subsequently performed 2PM-IR and 2PM-Vis testing without a filter in the mydriatic state. The second cohort study evaluated the effect of age on visual test performance in 42 healthy subjects split between two groups (ages 20-40 years and 60-80 years).

Results

Retinal sensitivity measured by 2PM-IR demonstrated lower variability than all other devices relying on visible spectrum stimuli. Retinal sensitivity decreased proportionally with the transmittance of light through each filter. CCT scores and retinal sensitivity decreased with age in all testing modalities. Visible spectrum testing modalities demonstrated larger test result differences between young and old patient cohorts; this difference was inversely proportional to the wavelength of the visual function test.

Conclusions

2PM-IR mitigates media opacities that may mask small differences in retinal sensitivity when tested with conventional visual function testing devices.

Translational Relevance

Conventional visual function tests that emit visible light may not detect differences in retinal function during the early stages of age-related diseases due to the confounding effects of cataracts. Infrared light, which has greater transmittance through ocular tissue, may reliably quantify retinal sensitivity and thereby detect degenerative changes early on.

New Service Model for Common Mental Disorders in Hong Kong: a Retrospective Outcome Study

OBJECTIVE

To review the first 8-month outcome of the Common Mental Disorder Clinic model in Hong Kong in terms of patient exit status and improvement in depressive and anxiety symptoms.

METHODS

During the first appointment, patients were interviewed by a multidisciplinary team comprising a psychiatrist, a psychiatric nurse, and an occupational therapist. A multidisciplinary case conference was conducted to discuss clinical observations, diagnosis, issues of concern, and the optimal individualised treatment plan. Low-intensity interventions by nurses and/or occupational therapists were provided, as were optional, time-limited, protocol-based interventions by clinical psychologists for those with mild to moderate depressive and anxiety symptoms. Pharmacological intervention may be used when indicated. Upon completion of the treatment plan, patients were reassessed by the treating psychiatrist. Discharge options included discharge without psychiatric follow-up, step-up to psychiatric outpatient clinics, and step-down services. The self-administered Patient Health Questionnaire-9 (PHQ-9) and Generalised Anxiety Disorder 7-item scale (GAD-7) were used to assess the past 2 weeks' depressive and anxiety symptoms, respectively, at baseline and at each session.

RESULTS

From July 2015 to February 2016, 1325 Chinese patients received the new service. Of them, 170 men and 363 women (mean age, 52.6 years) completed the treatment plan. After treatment, their mean PHQ-9 score decreased from 11.06 to 7.55 (p < 0.001), and the mean GAD-7 score decreased from 9.94 to 6.54 (p < 0.001). After treatment, 42.4% and 48.2% of the patients were within the normal range of PHQ-9 and GAD-7 scores, respectively, compared with 16.9% and 20.8% before treatment. The mean time to implementation of the individualised treatment plan was 82.33 days. Of the patients, 54.4% were discharged without any need for medical or psychiatric follow-up; 28% were stepped up to psychiatric outpatient clinics; and 17.3% were stepped down. The predictors of exit status were whether psychiatric medication was prescribed during initial intake (p = 0.011), whether psychiatric medication was prescribed at last follow-up (p < 0.001), the service period (p = 0.010), and the GAD-7 final score (p = 0.005).

CONCLUSIONS

The first 8-month outcome of the new service model was encouraging, with shortened waiting time, reduced severity of symptoms, and better exit status (high recovery and step-down rates).