Convergence insufficiency is easier to treat than CIES. In CIES, simple push-up (ramp) convergence exercises are not an adequate treatment (Chapter 10), probably because the deficiency is not simply a remote NPC. In NPCI, the deficit is solely of the NPC, and therefore ‘pencil-to-nose’ type exercises appear to be quite successful for NPCI (although there is a lack of evidence from randomised controlled trials). Some practitioners prefer ‘jump’ (step) convergence exercises in which the patient alternates their fixation between distance and near targets (Case Study 8.3). It is likely that a combination of both approaches will be more successful than either in isolation. Slightly more sophisticated exercises that include an appreciation of physiological diplopia can be very successful if properly understood by the patient. All these types of exercises are discussed in more detail in Chapter 10.

Patients will usually be able to teach themselves to develop a near point of convergence of less than 8 cm, and to perform jump convergence test quite quickly: usually in several weeks. Some authors argue that the exercise should be continued for 2 weeks after this, else the NPCI may recur. However, this is certainly not always the case (Case Study 8.3). Regardless of the approach, with some patients it may be necessary to repeat the exercises at intervals of a few months to maintain adequate convergence. If the NPCI does recur after a few months, more thought should be given to the possibility of aggravating factors such as poor general health, inadequate lighting, etc.

It is sometimes stated that voluntary convergence should be trained as the final stage of the treatment of NPCI (Bishop, 2001). One approach is for the patient to try to maintain convergence at their near point of convergence once the near fixation target has been removed. Free-space stereogram exercises usually involve an element of training voluntary convergence, when the patient reaches a stage when a pencil is not needed for fixation (Chapter 10).

In fact, any of the exercises that can be used to train convergent fusional reserves (Chapter 10) can be used to treat NPCI and Bishop (2001) recommended that convergent fusional reserve exercises should be part of the treatment plan for NPCI. Research indicates that an intensive programme of exercises is much more likely to be effective than simple pencil push-ups (Scheiman, Mitchell, Cotter, Kulp et al., 2005). Indeed, this research found that for CIES, more sophisticated exercises are necessary. The Institute Free-space Stereograms (pp. 152–156) have been used to successfully treat NPCI (Evans, 2000).