Lessons from a Prolific Career

Cheryl Guttman Krader reports.

During his decades-long career in ophthalmology, Sheraz M Daya MD has been an innovator and pioneer in refractive surgery. He reviewed his journey in the field and the lessons he learned in a keynote lecture - offering the following observation on the totality of his experience: “Surgical trends are like a fashion show - they come and go.”

Excimer laser experience

Dr Daya was introduced to refractive surgery more than 30 years ago when he learned radial keratotomy (RK) while completing a cornea fellowship. He performed RK after starting practice in the United States. Considering the multiple problems and complications associated with the incisional procedure, he was glad to be able to abandon it when he moved to England, where the excimer laser was available.

The surgeon performed his first LASIK procedure in the United Kingdom in 1994, recalling he experienced multiple flap issues while using a variety of mechanical microkeratomes in the early days of the procedure.

“The complications bothered me, and fortunately I could handle them because I was a corneal surgeon. I learned you have to be brave, and if you are going to be brave, you have to be prepared,” Dr Daya said.

He added this lesson reinforced itself when he encountered a horrifying complication involving perforation with iris prolapse when performing LASIK on top of a corneal graft.

“From then on, I always had a suture kit ready for any LASIK procedure just in case,” he said.

The introduction of the Orbscan (Bausch + Lomb) led to a new understanding of the effect of corneal shape and ectasia on refraction after penetrating keratoplasty (PK). With this knowledge, Dr Daya instead intervened with wedge resection rather than astigmatic keratotomy in many cases where the source of the problem was in the host cornea. It also led him to realise astigmatism remained in post-PK eyes after attempts to correct it with LASIK because the periphery was not ablated. From that observation, he adopted bitoric ablations and devised an effective approach for treating mixed astigmatism.

Studying the persistence of topically applied mitomycin-C (MMC) in the eye using an animal PRK model, Dr Daya and colleagues found the antimetabolite remained in the aqueous humour for up to six hours. The observation raised concern about the potential for long-term ocular toxicity, and he has continued avoiding the use of MMC for fear of contributing to what might be a public health problem. In response, he developed the transepithelial PRK approach on the Bausch + Lomb platform. It’s now incorporated in the Teneo (Technolas) laser software and works without the need for any nomogram change.

“A study of the technique is about to start in the United States, and hopefully, it will be approved for use there soon,” Dr Daya said.

Ignoring the gurus

Challenging the dogma LASIK should not be used to treat high levels of hyperopia, Dr Daya said the solution for achieving good outcomes requires creating a slow gradient of change by treating flat corneas and using a large optical zone (>6.7 mm), considering angle kappa, and avoiding an excessively deep ablation that might involve peripheral corneal nerve bundles.

In a very brief foray into conductive keratoplasty to treat hyperopia, Dr Daya said he found it induced a considerable amount of cylinder. He concluded that if the procedure can cause astigmatism, its best use may be treating astigmatism.

An early adopter of the PermaVision (Anamed Inc) synthetic corneal inlay to treat hyperopia, the innovator said he was excited by the good outcomes achieved early after surgery. However, on seeing evidence of an inflammatory reaction after evaluating inlays explanted from eyes that developed reticular haze, he learned another lesson—the cornea does not like anything but itself.

He subsequently avoided introducing synthetic corneal inlays but went on to perform the first case of TransForm Corneal Allograft implantation in the United Kingdom.

“So far, there have been no cases of haze, and the results are stable during follow-up to three years,” Dr Daya reported.

He began implanting phakic IOLs in 2002 and learned when using the iris-fixated Artiflex lens (while a great option, he added) that patients need to be monitored closely for the potential of rapid endothelial cell loss. He avoided using any angle-supported lenses for similar reasons.

“Like others, I came to the conclusion that if a lens is too close to the cornea, it is not good.”

That same year, he also began performing refractive lens exchange on relatively clear lenses. Through his journey using different types of presbyopia-correcting IOLs, Dr Daya found patients implanted with a zonal refractive lens were unhappy with their quality of vision. Complaints were understood by reviewing their aberrometry outcomes that showed the lens could cause a coma and other unwarranted aberrations, leading Dr Daya to abandon refractive technology in favour of diffractive lenses.

Noting that he has not performed SMILE, Dr Daya said the advantages of the newest femtosecond laser used for the procedure have given him more confidence in trying it.

He concluded his lecture by summing up his philosophy in one sentence: “Disregard the naysayers, ignore the gurus, and follow the evidence.”

Dr Daya presented at the AAO 2022 Refractive Surgery Subspecialty Day in Chicago, US.

Sheraz M Daya MD is the Medical Director, Centre for Sight, London, UK. sdaya@centreforsight.com