Intraocular pressure abnormalities associated with central and hemicentral retinal vein occlusion

Objective: To evaluate the prevalence of ocular hypertension (OHT) and glaucoma in patients with central retinal vein occlusion (CRVO) and hemi-CRVO (HCRVO) and of the fall in intraocular pressure (IOP) secondary to CRVO/HCRVO. Design: Nonrandomized comparative case series. Participants and Methods: We investigated 674 consecutive patients who were initially seen with unilateral CRVO (n = 548) and HCRVO (n = 126) at their onset, with a normal fellow eye. The fellow uninvolved eye in each patient acted as a control. Central retinal vein occlusion and HCRVO were categorized into nonischemic and ischemic. At all visits, patients had a detailed ocular history, as well as a thorough bilateral ocular evaluation, including IOP recording with a Goldmann applanation tonometer; when the diagnosis of OHT or glaucoma was initially uncertain, the 24-hour diurnal IOP was recorded. The observed prevalence rates of OHT and glaucoma among patients with CRVO and HCRVO were compared with those in the general population. Main Outcome Measures: The prevalence of OHT and glaucoma, and of ocular hypotension secondary to CRVO/HCRVO. Results: The overall prevalence of glaucoma was 9.9% and of OHT 16.2%. The prevalence of glaucoma/OHT was found to be significantly (P<0.0001) higher in patients with CRVO and HCRVO than in the general population. There was no significant difference in the proportion of patients with glaucoma/OHT among the various types of CRVO/HCRVO (P = 0.156). Forty-eight percent of all patients had lower IOP (≥2 mmHg) in the CRVO/HCRVO eye than in the fellow (uninvolved) eye at their initial evaluation. The prevalence of ocular hypotension was significantly (P<0.0001) higher in patients with glaucoma/OHT not on ocular hypotensive therapy than in patients without glaucoma. Among the patients without glaucoma, the prevalence of ocular hypotension differed significantly among the various types of CRVO/HCRVO (P = 0.007). Conclusions: Central retinal vein occlusion and HCRVO have a significant association with glaucoma and OHT and with a subsequent fall in IOP in the involved eye. Few patients with CRVO/HCRVO have high IOP in the involved eye, although many of them do have it in the fellow uninvolved eye. It is important to exclude glaucoma/OHT in the fellow eye of any patient with CRVO/HCRVO; if present, elevated IOP should be treated to reduce the risk of that eye developing (1) CRVO/HCRVO and (2) glaucomatous damage. There may be no benefit to prescribing IOP-lowering drops for involved eyes whose IOP is already normal.