OSN Associate Medical Editors discuss key developments of 1990s

Issue: February 25, 2022

ByLeon W. Herndon Jr., MD

ByJohn A. Hovanesian, MD, FACS

To celebrate the 40th anniversary of Healio/Ocular Surgery News, the Associate Medical Editors are sharing what they think are the most important ophthalmic innovations of the 1990s.

Antifibrotics in trabeculectomy

Leon W. Herndon Jr., MD: Trabeculectomy is still considered the gold-standard glaucoma surgery and has evolved over the past several decades in terms of surgical technique and approach, but perhaps the most profound alteration to the procedure has been the addition of antifibrotics. Steroids and NSAIDs inhibit wound healing early in the process, whereas anti-proliferative agents such as 5-fluorouracil and mitomycin C prevent scar formation by alteration of fibroblast proliferation and activity. 5-FU was initially used in vitro by Blumenkranz in 1984. The first clinical use of MMC was by Chen and colleagues in Taiwan in 1981, although their results were not published until 1990.

5-FU application required a series of subconjunctival injections during the first few weeks of the postoperative period after trabeculectomy. Although several studies found improved success rates with the addition of 5-FU, the increased number of visits and discomfort of repeated injections led to 5-FU being largely replaced intraoperatively by MMC using direct sponge or injection application. Today, surgeons use 5-FU primarily in the postoperative setting of imminent bleb failure.

The effect of MMC on fibroblasts has been shown to be much more potent and durable than 5-FU, requiring single-application doses of approximately 100 times less. There are numerous studies regarding the adjunctive use of MMC in glaucoma filtering surgery.

It can reasonably be concluded that MMC and 5-FU have demonstrated efficacy in their role as wound-modulating agents. Although their efficacy is apparent, one must balance the increased efficacy with the increased rate of complications with their use. The more profound benefit of their use appears to be in those patients at high risk for surgical failure or in patients requiring very low IOP goals.

References:
Blumenkranz MS, et al. Arch Ophthalmol. 1984;doi:10.1001/archopht.1984.01040030470029.
Carlson DW, et al. Ophthalmology. 1997;doi:10.1016/s0161-6420(97)30246-2.
Chen CW, et al. J Ocul Pharmacol. 1990;doi:10.1089/jop.1990.6.175.
Cheung JC, et al. Ophthalmology. 1997;doi:10.1016/s0161-6420(97)30347-9.
Cohen JS, et al. Ophthalmology. 1996;doi:10.1016/s0161-6420(96)30405-3.
Jampel HD. Ophthalmology. 1992;doi:10.1016/s0161-6420(92)31781-6.
Joshi AB, et al. J Glaucoma. 2005;doi:10.1097/01.ijg.0000151684.12033.4d.
Perkins TW, et al. J Glaucoma. 1998;7(4):230-236.
Shin DH, et al. Am J Ophthalmol. 1998;doi:10.1016/s0002-9394(99)80145-7.
Smith S, et al. Am J Ophthalmol. 1994;doi:10.1016/s0002-9394(14)72957-5.

A move to the clear cornea

John A. Hovanesian, MD, FACS: The 1990s were an incredible, pivotal decade for ophthalmology. Many surgeons in the U.S. started the decade performing cataract surgery through a large incision at least 6 mm in size, performing a can opener capsulotomy and removing the nucleus in bulk. Postoperative astigmatism was measured in full diopter increments, and pseudophakic bullous keratopathy was the most common indication for a corneal transplant, which was performed as penetrating keratoplasty.

Phacoemulsification might be the most important innovation that spread in popularity during that decade (although it was introduced in 1967). Indeed, it allowed us to use small incisions, tunneled through the sclera, to remove the lens. It facilitated folding lens implants that allowed less induced astigmatism. However, in my mind, the most pivotal change that occurred in the 1990s was the move to clear corneal cataract incisions. This trend happened near the end of the decade, popularized by Howard Fine and others. It made cataract surgery bloodless, sutureless and peribulbar-blockless — a revolution in the literal eyes of patients. Surgery became much faster, and those physicians still holding on to large incision techniques either adapted or quit doing cataract surgery.

Maybe most importantly, clear corneal cataract incisions gave consistent amounts of surgically induced astigmatism. This made it possible to consider refractive correction as part of our offering with cataract surgery. Refractive lenses followed, such as the AMO Array, which was introduced in September 1997.

The measure of a truly impactful innovation is its durability. Today, whether they are made with a metal keratome, a diamond blade or a femtosecond laser, whether we insert through them a monofocal, toric, multifocal or accommodating lens, the architecture of clear corneal cataract incisions has remained almost identical to what Dr. Fine introduced almost 30 years ago.

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Disclosures: Herndon and Hovanesian report no relevant financial disclosures.

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OSN Associate Medical Editors discuss key developments of 1990s

Antifibrotics in trabeculectomy

A move to the clear cornea

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