Heavier molecular weight ocular viscoelastic devices and timing of post-operative review following cataract surgery

BACKGROUND To assess the safety of abandoning the next day post-operative review in preference for assessment only 2 hours post-surgery for both phacoemulsification and extracapsular surgery with heavier molecular weight ocular viscoelastic devices (OVD). METHODS 475 patients who underwent uncomplicated cataract surgery using heavier molecular weight ocular viscoelastic device (Healon GV) were studied. Of these 415 were phacoemulsification and 60 extracapsular and none received Intraocular pressure (IOP) lowering prophylaxis at the end of surgery. All were examined at 2 hours post-surgery and on the following day. Results were tabulated and analysed assessing wound stability, corneal clarity, anterior chamber reaction and IOP. RESULTS In the time between the two assessments 44 (10.6%) patients developed a total of 53 new problems, with a majority being increases in IOP. Based on the lower threshold of IOP of 30 mmHg, the incidence of new problems at the next-day assessment was 9.8% (95% CI: 7.0 to 13.6) in the phacoemulsification group and 16.3% (7.3 to 29.7)in the extracapsular surgery group. At the higher threshold of IOP of 35 mmHg the corresponding figures were 6.6% and 16.3%. CONCLUSION There is a higher incidence of new problems at the next-day assessment than previous studies with conventional OVD. Therefore results from previous studies using standard OVDs cannot be simply extrapolated to heavier molecular weight OVDs. When these agents are used, routine use of an ocular hypotensive agent may be necessary to increase the safety of abandoning the review on the first post-operative day for phacoemulsification patients. This is to be studied.