Preoperative dry eye treatment contributes to high precision clinical outcomes

Background

Hadi Kjærbo is an experienced ophthalmic surgeon trained in Copenhagen and at Columbia University in New York. Following his specialization, he worked at the university hospitals in Copenhagen and Glostrup. Ten years ago, he founded SEC, a private clinic dedicated to cataract and refractive surgery.

Today, SEC is one of the largest private ophthalmic clinics in the Nordic region, treating more than 5,000 patients annually with a team of 14 full-time staff and additional consultants.

“We manage a broad spectrum of patients, including cataract, refractive lens exchange, and corneal laser procedures for myopia, hyperopia, and presbyopia,” Hadi explains.

The pre-operative assessment as a determinant of refractive accuracy

The pre-operative consultation is fundamental to planning the surgery and achieving predictable refractive outcomes. It encompasses a comprehensive evaluation of multiple parameters, including refraction, topography, keratometry, axial length measurements, and intraocular lens (IOL) calculation strategies, among others.

One component of this work-up is the assessment of ocular surface integrity, as tear film instability may compromise the accuracy and repeatability of biometric measurements.

“To consistently achieve a very high level of precision, reliable data is required for every parameter. That includes the ocular surface,” Hadi emphasizes.
At SEC, the pre-operative workflow begins with an optometrist-led examination, including visual function testing and initial screening. This is followed by a consultation with the ophthalmic surgeon, who reviews findings and confirms the surgical plan.

Screening for ocular surface disease (OSD) is systematically integrated into this process. If clinically significant OSD is identified, it is managed prior to proceeding with surgery.

Why pre-operative OSD assessment matters

Hadi’s focus on OSD originated early in his career:

“About 15 years ago, we encountered a few refractive surprises. The surgery itself was successful, and our calculations seemed correct, yet outcomes were suboptimal.”

A retrospective review revealed a common factor:

“When we reassessed corneal topography and clinical findings, tear film instability was a consistent feature. That was a turning point, it made us realise how critical the ocular surface is.”

High prevalance of pre-operative dry eye

A Norwegian clinical study (2023) demonstrated that more than 50% of cataract patients presented with dry eye disease (DED) pre-operatively, most of them asymptomatic.³

“This highlights why objective assessment is essential. Symptoms alone are not sufficient,” Hadi notes. “An unstable tear film affects keratometric readings and IOL power calculations. In some cases, the selected IOL power changes after treating dry eyes.”

Systemic screening and evaluation of OSD

At SEC, all patients undergo a structured tear film evaluation as part of the pre-operative assessment.

The optometrist performs the initial screening, assessing both signs and symptoms of OSD. Clinical evaluation includes:

• Corneal and conjunctival staining
• Tear film break-up time (TBUT)
• Schirmer test
• Meibomian gland assessment

“Our optometrists are trained to identify OSD and initiate treatment. This ensures early intervention and consistency in care,” Hadi explains.

If OSD is deemed visually significant, meaning it may affect measurement accuracy or surgical outcomes, treatment is initiated in accordance with the ASCRS pre-operative algorithm.

Pre-operative optimisation and re-evaluation

Patients undergoing treatment for OSD are re-evaluated after 2–4 weeks, depending on severity.

“Once corneal staining has resolved and tear break-up time has improved, indicating a stable tear film, we repeat all relevant measurements before proceeding,” Hadi says.

Only when the ocular surface is considered stable does the clinic proceed with final surgical planning.

Practical approach: No advanced technology required

Hadi emphasises that effective OSD assessment does not require advanced instrumentation:

“A slit lamp and fluorescein staining are sufficient for a basic, reliable evaluation. With proper technique, you can assess tear film quality and meibomian gland function effectively.”

Impact on outcomes and patient satisfaction

SEC achieves its refractive target (±0.50 D) in 98% of cases. According to Hadi, this is the result of a systematic and meticulous pre-operative approach:

“It’s not one single factor, it’s the combination of several, for example: accurate biometry, appropriate intraocular lens (IOL) formulas, lens constant optimisation, and optimisation of the ocular surface.”

Residual refractive errors and postoperative dissatisfaction have decreased as a result.

He highlights a particular relevance in premium IOLs:

“In patients with astigmatism, tear film instability can affect keratometry. I would strongly advise against implanting multifocal IOLs without first assessing and managing OSD.”

Optimising IOL calculations

Hadi has a strong interest in IOL calculation formulas and their impact on outcomes, and when new technologies emerge, he continuously evaluates their potential to further optimise clinical outcomes:

“Combining a meticulous pre-operative evaluation, including systematic optimisation of the ocular surface, with the adoption of newer-generation formulas improved our outcome precision.”

“At SEC, this includes the use of the Hill-RBF method, a data-driven, artificial intelligence-based approach to IOL power calculation. Unlike traditional vergence-based formulas, the Hill-RBF algorithm is based on pattern recognition derived from large datasets of postoperative outcomes. This allows for highly accurate predictions within its validated biometric range.”

“What I find particularly valuable is that it is less dependent on assumed effective lens position. When your input data are reliable, especially keratometry and axial length, you get very consistent results,” Hadi explains.

He emphasises, however, that the accuracy of any formula remains dependent on the quality of the pre-operative measurements:

“Even the most advanced formula cannot compensate for poor data. That’s why optimisation of the ocular surface and lens constant refinement remain essential.”