Surgery for Keratoconus

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Keratoconus Surgery

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Surgery for Keratoconus

Topography-Guided PRK for Keratoconus

What is Topography-Guided Photorefractive Keratectomy (TG-PRK)?

Photorefractive keratectomy is a refractive surgical procedure that removes the surface skin cells of the cornea, and then uses an excimer laser to reshape the cornea in order to correct vision problems, such as nearsightedness, farsightedness and astigmatism. With topography-guided photorefractive keratectomy (TG-PRK), the excimer laser with PRK is used to smooth out the surface of a patient’s eye, and reduce optical irregularities that would otherwise cause distortions in a patient’s vision. Corneal topography technology is used to create a series of three-dimensional maps of the corneal surface. This information is combined with the patient’s refractive error to develop a precise and personalized vision correction plan using the laser technology. Irregularities on the surface of the eye are smoothed out, which increase a person’s overall quality of vision. These irregularities on the cornea – called higher-order aberrations – act like peaks and valleys on what would otherwise be an ideally smooth surface. These aberrations may lead to poor night vision, glares and haloes, starbursts, and low-contrast vision problems.

In TG-PRK for keratoconus, the laser is used to correct the cone-shaped corneal irregularities that are causing distortions. By using the patient’s custom corneal topography data, the laser reshapes the corneal surface to improve the cornea’s shape and visual performance. The goal is to improve the cornea’s architecture in order to enhance vision with glasses or contact lens fit, depending on the need of the patient.

TG-PRK for the treatment of Keratoconus

In TG-PRK for keratoconus, the laser is used to correct the cone-shaped corneal irregularities that are causing distortions. By using the patient’s custom corneal topography data, the laser reshapes the corneal surface to improve the cornea’s shape and visual performance. The goal is to improve the cornea’s architecture in order to enhance vision with glasses or contact lens fit, depending on the need of the patient.

TG-PRK with Corneal Collagen Cross-Linking

What kind of technology is Corneal Topography?

Corneal topography is a computer assisted diagnostic tool that creates a three-dimensional map of the surface curvature of the cornea. The cornea is the transparent, outermost layer of the eye and it plays an important role in focusing your vision. An evenly rounded cornea results in normal vision. If a cornea is irregularly shaped, such as too steep, flat or unevenly curved, vision will be impaired. Corneal topography produces a detailed, visual map of the cornea’s shape and power. This detailed information is used to diagnose, monitor, and treat various eye conditions. It is also used in fitting contact lenses and for planning surgery, including laser vision correction. For laser vision correction the corneal topography map is used in conjunction with other tests to determine exactly how much corneal tissue will be removed and which ablation pattern will be used.

What is the recovery time with TG-PRK?

As done with PRK, the procedure begins by gently removing the central portion of the corneal coating, or epithelium, using a special solution or a surgical device. Once the epithelium is removed, a laser that is programmed with the patient’s topographic and refractive measurements is used to gently remove microscopic amounts of the corneal tissue so it can be reshaped. A special contact lens will be placed on the to protect the cornea while new epithelial cells form, a process that takes several days.

Medical Literature on TG-PRK for Keratoconus

Zhang Y, Chen Y: Topography-guided corneal surface laser ablation combined with simultaneous accelerated corneal collagen cross-linking for treatment of keratoconus. BMC Ophthalmol 2021, 21(1):286.
Sachdev GS, Ramamurthy S, B S, Dandapani R: Comparative Analysis of Safety and Efficacy of Topography-Guided Customized Cross-linking and Standard Cross-linking in the Treatment of Progressive Keratoconus. Cornea 2021, 40(2):188-193.
Russo A, Faria-Correia F, Rechichi M, Festa G, Morescalchi F, Semeraro F: Topography/wavefront-guided photorefractive keratectomy combined with crosslinking for the treatment of keratoconus: preliminary results. J Cataract Refract Surg 2021, 47(1):11-17.
Kymionis G, Kontadakis G, Grentzelos M, Petrelli M: Long-Term Follow-Up of Combined Photorefractive Keratectomy and Corneal Crosslinking in Keratoconus Suspects. Clin Ophthalmol 2021, 15:2403-2410.
Singal N, Ong Tone S, Stein R, Bujak MC, Chan CC, Chew HF, El-Defrawy S, Jin Y, Kranemann C, Rabinovitch T et al: Comparison of accelerated CXL alone, accelerated CXL-ICRS, and accelerated CXL-TG-PRK in progressive keratoconus and other corneal ectasias. J Cataract Refract Surg 2020, 46(2):276-286.
Kanellopoulos AJ: Keratoconus Management With Customized Photorefractive Keratectomy by Artificial Intelligence Ray-Tracing Optimization Combined With Higher Fluence Corneal Crosslinking: The Ray-Tracing Athens Protocol. Cornea 2021, 40(9):1181-1187.
Kanellopoulos AJ, Vingopoulos F, Sideri AM: Long-Term Stability With the Athens Protocol (Topography-Guided Partial PRK Combined With Cross-Linking) in Pediatric Patients With Keratoconus. Cornea 2019, 38(8):1049-1057.
Kanellopoulos AJ: The impact of keratoconus treatment with the Athens Protocol (partial topography-guided photorefractive keratectomy combined with higher-fluence corneal collagen cross-linking) on quality of life: a long-term study. Clin Ophthalmol 2019, 13:795-803.
Kanellopoulos AJ: Management of progressive keratoconus with partial topography-guided PRK combined with refractive, customized CXL - a novel technique: the enhanced Athens protocol. Clin Ophthalmol 2019, 13:581-588.
Kanellopoulos AJ: Ten-Year Outcomes of Progressive Keratoconus Management With the Athens Protocol (Topography-Guided Partial-Refraction PRK Combined With CXL). J Refract Surg 2019, 35(8):478-483.
Nattis A, Donnenfeld ED, Rosenberg E, Perry HD: Visual and keratometric outcomes of keratoconus patients after sequential corneal crosslinking and topography-guided surface ablation: Early United States experience. J Cataract Refract Surg 2018, 44(8):1003-1011.
Nattis AS, Rosenberg ED, Donnenfeld ED: One-year visual and astigmatic outcomes of keratoconus patients following sequential crosslinking and topography-guided surface ablation: the TOPOLINK study. J Cataract Refract Surg 2020, 46(4):507-516.
Sakla H, Altroudi W, Munoz G, Sakla Y: Simultaneous Topography-Guided Photorefractive Keratectomy and Accelerated Corneal Collagen Cross-Linking for Keratoconus. Cornea 2016, 35(7):941-945.
Shetty R, Israni NA, Ramuka S, Dadachanji Z, Roy AS, Mehra R, Lalgudi VG: Intracorneal Ring Segments Followed by Simultaneous Topography-Guided Removal of Epithelium and Stroma With Accelerated Collagen Cross-Linking For Keratoconus (I-TRESK/CXL). Asia Pac J Ophthalmol (Phila) 2020, 10(2):152-160.
Kremer I, Aizenman I, Lichter H, Shayer S, Levinger S: Simultaneous wavefront-guided photorefractive keratectomy and corneal collagen crosslinking after intrastromal corneal ring segment implantation for keratoconus. J Cataract Refract Surg 2012, 38(10):1802-1807.
Ferreira GA, Ghanem VC, Tavares RLP, Ghanem RC: Toric Artisan after transepithelial topography-guided photorefractive keratectomy for higher-order aberrations following intrastromal corneal ring segments in keratoconus - Trioptics. Indian J Ophthalmol 2020, 68(11):2564-2567.

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