MONOVISION

While surgeons now have an array of potential solutions for presbyopia such as PresbyLASIK, multifocal IOLs and intracorneal inlays, the tried-and-trusted approach of refractive laser monovision correction remains an effective technique in the longer term, Tasneem Khatib MD reminded delegates attending the XXIX Congress of the ESCRS.

“Monovision works well, but rigorous patient selection criteria need to be adhered to in order to obtain optimal outcomes. While there does not appear to be any single factor that contributes to patient dissatisfaction, patients do need to be carefully counselled preoperatively and be willing to accept and adapt to visual compromises such as reduced visual acuity, loss of stereopsis and the potential need for top-up glasses for driving,†she said.

Her retrospective study included 170 patients, 137 women and 33 men with a mean age of 51.7 who underwent LASIK or LASEK procedures between 2002 and 2010 at the MDA Clinic in Cardiff, Wales. The mean follow-up time was 52 months and one surgeon performed all procedures.

Dr Khatib emphasised that all patients were carefully counselled prior to selection. Those that had professions where binocular vision was required, for instance night-time lorry drivers, crane operators, professional tennis players and so forth, were not selected. Patients were sent questionnaires postoperatively and asked to comment on a variety of factors, including whether they required glasses for tasks such as driving, reading, television and general routine activity.

Among eyes that were targeted for near vision 88 per cent achieved N5 or better unaided vision. In eyes targeted for distance correction, 99 per cent achieved 6/12 or better uncorrected visual acuity, which is the legal requirement for driving in the UK.

Five patients (2.9 per cent) required enhancement and three (1.75 per cent) required reversal of monovision. Of the 170 patients who underwent surgery, 101 responded to the patient satisfaction questionnaire. Of these, 74 patients reported their vision to be as they expected or better than expected, while 27 patients reported their vision to be less than they expected.

Looking at these groups in greater detail, Dr Khatib noted that the number of myopes and hyperopes were similar across both groups as was the age profile and male-female ratio. There did not appear to be any single activity either for distance or near work from those measured that was significantly affected in the patients reporting less than expected vision compared to those who were satisfied with their postoperative vision.

In terms of time needed to adapt to monovision, the majority of patients adapted to monovision within three months of having had the surgery. One per cent of patients in both satisfied and non-satisfied groups required glasses for routine activities, while 12 per cent of the less satisfied group required glasses for driving compared to nine per cent in the satisfied group.

Summing up, Dr Khatib emphasised that managing patient expectations holds the key to successful outcomes in monovision procedures.

“While there did not seem to be any one factor in particular which contributed to patient dissatisfaction, out of the ones we measured we think that patient expectations need to be carefully considered, and they need to be carefully counselled and selected preoperatively and be prepared to accept certain compromises in their vision such as loss of stereopsis or the potential need for top-up glasses until better techniques become more widely available,†she concluded.

contact Tasneem Khatib – tasneem.khatib@lmh.ox.ac.uk