**Conflict of interest**

All authors have no financial/proprietary interest in the subject matters of the manuscript.

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**Author details**

Claire Chow1,2 and Poemen Pui-man Chan1,2\*

\*Address all correspondence to: poemen@gmail.com

provided the original work is properly cited.

The People's Republic of China

1 Department of Ophthalmology and Visual Sciences, The Chinese

University of Hong Kong, Hong Kong Eye Hospital, Kowloon, Hong Kong,

2 Hong Kong Eye Hospital, Hong Kong, SAR, The People's Republic of China

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

*Risk Assessment of Ocular Hypertension and the Use of Medication*

*DOI: http://dx.doi.org/10.5772/intechopen.90804*

*Risk Assessment of Ocular Hypertension and the Use of Medication DOI: http://dx.doi.org/10.5772/intechopen.90804*

*Visual Impairment and Blindness - What We Know and What We Have to Know*

which future assessments will be compared with.

need to refine our existing risk assessment methodology.

future glaucoma study design.

**6. Conclusion**

**Conflict of interest**

manuscript.

and Ocular Hypertension (LiGHT) trial is a multicentre RCT that compared eye drops versus selective laser trabeculoplasty as first-line treatment for POAG or OHT [43]. The study is unique with its well-constructed algorithm for detecting disease progression and guiding treatment escalation [44]. It has a novel approach to defining target IOP. Firstly, the target IOP is specific for each patient at baseline, based on disease severity and lifetime risk of loss of vision at recruitment (e.g. different target pressure and percentage IOP reduction according to the disease stratification suggested by Mills et al. [45]). Secondly, the IOP was adjustable based on IOP control and disease progression [44]. The disease progression (either glaucoma deterioration or conversion of OHT to POAG) was determined by a decision support software based on objective visual field and optic disc imaging criteria. Disease progression was defined as 'strong evidence', with the Humphrey GPA software showing 'likely progression' and/or HRT rim area > 1% per year (at *P* < 0.001), and 'less strong evidence' with GPA showing 'possible progression' and/or HRT rim area > 1% per year (at *P* < 0.01). 'Likely visual field progression' is the presence of three or more points on the GPA at <0.05 probability for change on three consecutive occasions, while 'possible visual field progression' is the same criterion but on only two consecutive occasions [44]. Optic disc progression was defined as the rate of neuroretinal rim loss exceeding 1% of baseline rim area/year on a minimum of five repeat HRT images, where this is equivalent to approximately twice the value of normal age-related rim area loss [22]. Following treatment escalation, there is a resetting of both the target IOP and visual field and optic disc baselines against

Although the LiGHT trial is probably more complex in its target IOP setting algorithm compared with other glaucoma trials which defined treatment success based on the proportion of patients achieving a particular target percentage reduction of IOP, it resembled closer to our clinical practice. For instance, further IOP lowering beyond the 'target IOP' is probably required for patients with progressive disease. In some cases, patients might request to reduce medication use even when the target IOP is not achieved (e.g. OHT patients with IOP at 24 mmHg who do not want treatment and show no signs of POAG conversion). Furthermore, the LiGHT trial is also unique in that it included the evaluation of quality of life as an outcome measure. These are all novel features that might become important components for

It is more cost-effective to selectively treat OHT subjects who have a higher risk of POAG conversion. However, risk assessment can be difficult due to the variabilities in the measurement of the baseline variables of the glaucoma risk calculator. In the era of advancing OCT technology and knowledge of glaucoma, there may be a

All authors have no financial/proprietary interest in the subject matters of the

**126**
