IOP rise in consensual eye after glaucoma surgery

 

A significant increase in IOP in the fellow eye (FE) after glaucoma surgery in the index eye (IE) has been noted by some researchers. Although, there are also reports of reduction in IOP in the FE after surgery in the IE.

See post on AMTT here: https://ourgsc.blogspot.com/search?q=AHMAD%27S

In a study performed on 187 consecutive glaucoma patients, who underwent either trabeculectomy or Ahmed Glaucoma Valve (AGV) implantation, it was found that nearly a third of them required medical or surgical management of IOP in the FE following surgery of the IE. [1]

In the study, 87.7% patients underwent trabeculectomy and 12.3% underwent AGV implantation.

Incidentally, in 84% of the patients the FE was already glaucomatous and 22 eyes had undergone trabeculectomy.

The mean IOP rise in FE among all patients (trabeculectomy and AGV), was as follows:

Pre-operative IOP in IE	17.6± 6.9 (n-187)
Pre-operative IOP in FE	14.48± 3.4 (n‑187)
IOP in FE: Post-op 1 day	14.54 ± 4.9 (p‑ 0.694)
Post-op 1 week	15.8 ± 5.5 (p‑0.005)
Post-op 1 month	15.62 ± 5.7 (p‑0.007)
Post-op 3 months	15.09 ± 5.0 (n‑135, p‑0.279)

 

Among patients with AGV shunt surgery (n=23), the mean fellow eye IOP was higher than baseline at all‑time points, with maximum rise on day 1 (15.91 ± 6.3, baseline 13.78 ± 2.7; n‑ 23, p‑0.066).

Pre‑operative acetazolamide (n=43) strongly predicted a statistically significant increase in FE mean IOP.

Among all patients, 15% required additional intervention to control IOP in the FE in the first 30 days and 33% in the first 90 days after glaucoma surgery in the IE.

In the trabeculectomy group, 35% patients required an increase in the anti-glaucoma medications or surgery in the FE, within 90 days of surgery in the IE.

In the AGV group, 18% patients required additional intervention in the FE within 90 days of surgery in the IE.

Among all patients, 14.4% eyes required surgical intervention in the FE.

Other studies have also noted a significant increase in IOP in the FE after glaucoma surgery. Meshksar reported maximum IOP rise 1 week after surgery [2], while Kaushik noted it at 6 weeks following surgery [3].

Incidentally, Kaushik did not report any significant association with acetazolamide.

A number of explanations have been surmised for this phenomenon. It is assumed that patients stop the anti-glaucoma medications in FE after surgery in one eye. 

Another potential explanation for the rise in IOP would be the sequelae of under-perfusion of the scleral meshwork due to preferential flow through the sclerostomy site. Under-perfusion results in meshwork densification, activation of endothelial cells and increase in extracellular matrix both in the ipsilateral and contralateral eye offering resistance to aqueous outflow and in turn contributing to the rise in consensual eye IOP. 

It has also been postulated that the scleral spur consists of special cells that play an important role in the afferent pathway of the reflex that controls bilateral ciliary body and meshwork contractile tone. Surgery in one eye could affect the other eye through these cells.

These studies indicate that close monitoring is required for the consensual eye after glaucoma surgery in one eye.

REFERENCE:

[1] Rajsrinivas D, Dubey S, Pegu J, Majumdar A. Consensual eye intra-ocular pressure rise following unilateral glaucoma surgery. Indian J Ophthalmol. 2023 Mar;71(3):873-879. doi: 10.4103/ijo.IJO_1909_22. PMID: 36872698; PMCID: PMC10230001.

[2] Meshksar A, Hajizadeh M, Sharifipour F, Yazdani S, Pakravan M, Kheiri B. Intraocular pressure changes in the contralateral eye after glaucoma surgery. J Glaucoma 2021;30:1074‑81.

[3] Kaushik S, Agarwal A, Kaur S, Lomi N, Raj S, Pandav SS. Change in intraocular pressure in the fellow eye after glaucoma surgery in 1 eye. J Glaucoma 2016;25:324–9.