Light Adjustable Lens Customise Your Vision Post Cataract Surgery

Deepika Biswakarma, Master’s of Optometry

Optometrist at Suvidha Optician, Jammu

 

Although surgical techniques have advanced over the years, most patients still need refractive correction to fulfill their visual needs post-surgery due to several reasons such as difficulty in outcome prediction, wrong Intra-Ocular Lens (IOL) selection, inaccurate biometry etc. To tackle this problem, we now have premium IOL: Light Adjustable Lens (LAL).⁽¹⁾ The first and only IOL approved by the Food and Drug Administration (FDA) on 22^nd November 2017. ⁽²⁾

Introduction

LAL is mold-able, a 3D structured IOL based on the principle of photochemistry and diffusion. ⁽³⁾ It is made up of photo-reactive molecules embedded uniformly in a silicone matrix. Being a more advanced IOL in the market, it is considered as a novel way to deliver customised mono-vision. Whereas a standard IOL can’t be adjusted after surgery.

Technique

The procedure of cataract surgery is like any other standard IOL implantation, but the difference occurs post operation. After wound healing (2-4 weeks), refraction is performed and if there is residual refractive error or patient is unsatisfied with the visual outcomes, then the LAL shape can be modified with the help of Light Delivery Device (LDD) attached within the slit-lamp. It is a painless treatment where a low intensity of UV light (365nm) is projected on LAL with contact lens on and through a dilated pupil (6.5-7mm). ⁽³⁾ On the 90 second exposure, this light treatment helps to mold optics of photo-reactive silicone lens either in the central or peripheral region based on power change. In hyperopic correction, light is exposed to the center of the lens so that monomers migrate there which eventually thicken the central portion and flatten the periphery of lens and vice versa for myopia correction ⁽⁴⁾. Most patients require 2-4 light sessions over a 3 day interval to acquire a satisfied vision goal ⁽²⁾. The eye drops and precaution post operation is identical to typical cataract surgery. The patient must wear UV protective glasses all the time except while bathing and sleeping until the light procedure is complete. This comprises a very crucial step because exposure to light may cause unintended vision changes ⁽⁵⁾. LAL allows the patient to use trial and error to preview various lens power like in spectacles. The adjustment range of refractive outcomes are (-2.00 to +2.00D) for spherical and (-0.75 to -2.00D) for cylindrical power ⁽⁶⁾. The final step of this technique is a “lock in” procedure which is done when the patient is finally satisfied with customized visual correction.

Figure 1: Hyperopic change in optic of LAL

[Picture courtesy: Jain S, FICO M, DelMonte DW. Light Adjustable Intraocular lenses, https://eyewiki.aao.org/Light_Adjustable_Intraocular_lenses]

Indication/Contraindication:

Well-motivated and compliant patients having cataract and corneal astigmatism of at least 0.75D without any anterior and posterior pathology are suitable for this IOL option ⁽³⁾.

Patients who are under medications that increase sensitivity to UV light or retino-toxic meditations are out of selection criteria. Also, patients with pre-existing macular disease, having a history of herpes eye disease, nystagmus is also discouraged to take part in such procedures ⁽³⁾.

Complications:

The procedure may bring up minor complications such as alteration in colour vision which tends to resolve later. Corneal abrasion is rare when there is faulty handling of the contact lens during LDD ⁽³⁾.

Advantage / Disadvantage:

With the major feature of adjustment of vision post implantation, there’s no need for any additional procedure. It simplifies pre – operative decision making. It is considered as a more accurate lens option for patients with previous LASIK, PRK or Radial Keratotomy history ⁽²⁾. LAL prevents post capsular opacification and rotation of IOL within the capsular bag which makes LAL suitable for toric correction ⁽³⁾.

The only drawback of the IOL is its higher cost ⁽⁴⁾. Moreover, the patient should not have poor pupil dilation and they should have time commitment for in-office visits ⁽⁵⁾.

Conclusion:

In an FDA study conducted among 600 patients, the success rate of achieving uncorrected distance vision 20/20 was twice in LAL compared to standard IOL ⁽³⁾. A study has proved that “Seven years after implantation and refractive adjustment, eyes with LAL had stable refraction, good visual acuity, and no IOL- associated pathologies ⁽⁷⁾.” Thus, LAL has proven to be a safe, accurate and reliable approach to non- surgical correction of post-operative surprises ⁽⁵⁾.

 

Reference:

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2. Light adjustable lens™ in River Forest, il: Kirk eye center. Light Adjustable Lens™ in River Forest, IL | Kirk Eye Center. (n.d.). Retrieved February 25, 2023, from https://kirkeye.com/services/cataracts/light-adjustable-lens-river-forest-il
3. Light adjustable intraocular lenses. EyeWiki. (2022, October 2). Retrieved February 25, 2023, from https://eyewiki.aao.org/Light_Adjustable_Intraocular_lenses
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5. Chatterjee, A. (2022, May 5). The latest advancement in cataract surgery: Light adjustable lenses. OOMC. Retrieved February 25, 2023, from https://oomc.com/blog/the-latest-advancement-in-cataract-surgery-light-adjustable-lenses/
6. SUMMARY OF SAFETY AND EFFECTIVENESS DATA (SSED), https://www.accessdata.fda.gov/cdrh_docs/pdf16/P160055B.pdf
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