Dr Nabila Jones, Dr Irene Sisó-Fuertes, Mr Amir Hamid and Dr Clare O’Donnell present a case study showing the patient journey and expected outcomes with the laser blended vision, or Presbyond, technique

Background 

First introduced in 2009, laser blended vision or Presbyond (Carl Zeiss Meditec, Jena, Germany), is now being performed as a technique in presbyopia correction surgery.1-3 Presbyond is a LASIK procedure where enhanced micro-monovision is attained. The dominant eye is corrected for distance vision to almost plano and the non-dominant eye is corrected to be slightly myopic for near vision (up to -1.50DS). The micro-monovision strategy is further enhanced by an increase in the depth of field in each eye using a wavefront optimised ablation. Presbyond laser blended vision is an individualised treatment plan based on pre-operative spherical aberration and the ‘functional’ age of the eye. As a result, a customised fusion of the two images for near and distance vision is created for each patient; a so-called blend zone. Typically, the induced anisometropia is low enough for patients to maintain functional stereoacuity while uncorrected, and to not lose best corrected visual acuity.4 

The Presbyond procedure draws on the following mechanisms to increase depth of field:  

  • Pupil constriction during accommodation
  • Increase of corneal spherical aberration
  • Retinal and central cortical processing; neuronal gating and blur-suppression
  • A blend zone that enables simultaneous binocular vision thus preserving stereoacuity.4-6

  

A reported advantage of Presbyond over other presbyopia corrective surgeries include minimised exposure to the risks that can be associated with intraocular lens surgery procedures.1,3,7 

The purpose of this case report is to describe the visual and refractive outcomes of a 55-year-old female patient with longstanding meibomian gland dysfunction (MGD) to illustrate the Presbyond LASIK procedure.  

  

Case 

A 55-year-old, female, hyperopic, presbyopic patient was seeking freedom from spectacles and contact lenses, having had issues with contact lens deposits impacting vision (figure 1, above, Courtesy of C Gore).  

A particular issue with her monovision contact lens wear was the deposition, which was causing very significant reductions in distance or near vision depending on the contact lens affected. Different lens materials were trialled and, although some improvement was experienced, episodes of non-compliance to recommended wear schedules (such as occasional overnight wear) and swimming while wearing lenses were reported on occasion, increasing the risk of corneal infection.  

On examination, the local suitability criteria for Presbyond were met. These include the following indications: 

  • Presbyopes aged 40-60 years approximately
  • Suitable for LASIK
  • No contraindicating ocular or systemic conditions

  

Specific contraindications for Presbyond include: 

  • Intolerance to micro-monovision demonstrated during assessment at clinic (reported as ‘cross blur’)
  • A history of contact lens monovision intolerance
  • Corrected distance visual acuity (CDVA) worse than 6/7.5 in either eye or a preoperative subjective refraction outside the treatment range of -8.00DS to +2.00DS with up to 2.00DC of cylinder
  • Other established contraindications to undergoing LASIK, such as keratoconus, corneal dystrophy, Graves’ disease, and active inflammatory or infectious eye disease, are also applicable to patients seeking Presbyond.

  

The patient had a history of epithelial erosion caused by a paper cut to the left eye (approximately nine years prior to surgery), longstanding MGD, contact lens related peripheral ulcers and chalazia (figure 2). Conservative methods, occasional use of hot compresses, lid hygiene procedures and ocular lubricants were used as part of past treatment regimens for dry eye disease. 

  

Figure 2: Meibomian gland dysfunction and chalazion

 

Pre-operative Procedures

Pre-operative testing protocol for Presbyond include the following steps: 

  1. Manifest refraction 
  2. Eye dominance testing 
  3. Laser blended vision tolerance assessment with myopic target to establish tolerance to micro- monovision. The standard micro-monovision protocol would correct the dominant eye to plano and the non-dominant eye to up to -1.50DS while assessing the patient’s response to distance and near viewing. In brief, tolerance is evaluated as the amount of cross blurring reported by the patient during demonstration of the intended postoperative refraction using a phoropter. Cross blurring describes the lack or reduction of interocular blur suppression. The assessment is repeated with the 1.50DS demonstration in the dominant eye and the level of ‘addition’ can be reduced if 1.50DS is not tolerated by either eye. 
  4. Laser blended vision explanation and patient counselling, to ensure the patient fully understands the treatment, how it works, whether it matches their expectations and what to expect throughout the post-operative period in terms of signs, symptoms and vision. The discussion of the post-operative course in terms of refractive changes and fluctuation is tailored according to the patient’s pre-operative refraction and circumstances. 

  

The patient in this case was instructed not to wear soft contact lenses for at least 48 hours prior to the initial pre-operative consultation and to suspend lens wear for at least a further 48 hours before treatment.  

Pre-operative examination followed a standardised protocol. Ocular motor balance was assessed, and eye dominance recorded using a motor dominance test. Manifest and cycloplegic refraction were obtained. Infrared pupillography, anterior segment examination using slit-lamp biomicroscopy, tear film assessment (measuring tear break-up time and tear meniscus height), tonometry and indirect slit-lamp biomicroscopy fundus examination were carried out. Further diagnostic evaluations were performed using a topographer, aberrometer and a specular microscope. 

After an initial one-month course of treatment for dry eye disease, a surgeon review was performed. The patient was again counselled to expect a period of post-operative adaptation while the brain adjusts to process the images from the two eyes, which typically can take up to three months. Patients are advised that this period varies and are encouraged to refrain from closing each eye to compare vision during the adaptation phase. The patient gave informed consent and was subsequently listed for bilateral Presbyond laser blended vision correction surgery in July 2019.  

  

Pre-operative Examination Results  

Ocular examination revealed MGD, with binocular low tear meniscus height (0.2mm centrally) and a fluorescein TBUT of three seconds. No lens opacities were recorded. Examination revealed right eye dominance. The laser blended vision tolerance assessment ‘cross blur test’ demonstrated acceptance of monovision with +1.50DS add in the left eye, which resulted in binocular VA 6/5, N4 with no reported cross-blur. Manifest refraction results are outlined in table 1.  

 

Table 1: Pre-operative manifest refraction outcomes, intraocular pressure (IOP) and scotopic pupil size. *Asterisk indicates the dominant eye

CDVA = corrected distance visual acuity;
CNVA = corrected near visual acuity; CIVA=Corrected intermediate visual acuity

 

Surgical Technique

The surgical procedure was performed under local anaesthetic. The femtosecond Visumax (Carl Zeiss Meditec, Jena, Germany) laser platform was used to create a uniform corneal flap and the MEL90 (Carl Zeiss Meditec, Jena, Germany) excimer laser was used to ablate the cornea.  

  

Flap thickness was: 100microns 

Flap diameter: 8.90mm, superior hinge 

  

Surgical treatment:  

  • R: +1.50 DS, target refraction plano
  • L: +2.57/-0.25 x 150, target refraction -1.50 DS

  

The patient was asked to wear plastic shields while sleeping for seven nights, and prescribed prednisolone 0.5%, one drop hourly, both eyes, for one day and then four times a day for seven days, Oftaquix 0.5%, one drop, both eyes, four times a day for seven days, Hyabak 0.15% hyaluronic acid preservative free, one drop as required for four weeks before review.  

  

Post-operative Examination  

Surgical refraction targets were achieved one-month post-operatively, see table 2. Post-operatively corneal ablation was well centred. Dry eye signs were recorded up to one month postoperatively for which the patient continued to use the prescribed ocular lubricants.

The refractive outcomes are outlined with three years follow up at the time of writing. Figure 3 shows the pre- and post-operative aberrometry results. 

 

Table 2: Post-operative refraction outcomes over time  

 

Discussion

The patient journey and expected outcomes with Presbyond are highlighted by this case.  

The Presbyond procedure proved to be a highly effective solution for this patient who is spectacle independent for distance, intermediate and near. Neuroadaptation was achieved within a month or so, with no reports of unwanted visual phenomenon to date.

This case reaffirms the findings of previous studies4, 5 where it is reported that patient post-operative vision and acceptance of the Presbyond procedure are excellent in appropriately counselled patients.  

MGD is one of the most common ocular surface diseases and the main cause of evaporative dry eye disease (DED).8 Along with its effect on the ocular surface, DED has been reported to impair vision-related quality of life and other aspects of social and psychological functioning.9 Subjectively, the individual in this case reported the ocular issues caused by MGD actually improved post-operatively and reduced her symptoms of evaporative DED. Long-term contact lens wear has been reported to predispose individuals to MGD.10 It is possible that the improvement of symptoms that occurred postoperatively were due to cessation of contact lens wear.  

Long-term concerns with laser patients are refractive stability and the development of visually significant cataract. Although the patient achieved and has maintained excellent postoperative visual acuity she was counselled that there is a possibility that a top-up treatment may be required in future, eg to enhance near vision in the non-dominant eye. If the patient does develop significant cataract in future, the existing depth of field can be combined with a monofocal IOL and micro-monovision to retain the full range of vision currently being enjoyed. 

  

Conclusion 

Presbyond laser blended vision creates an individually customised binocular treatment plan performed as a LASIK procedure. The aim is to adjust each eye specifically to contribute visual information with the dominant eye adjusted to see full distance vision and some intermediate range vision while the non-dominant eye is adjusted to focus at intermediate and near vision. This enables the brain to blend both eyes images more easily creating binocular and stereoscopic vision over an extended range that is more than standard monovision. It is envisaged that this case study may be informative for clinicians assessing presbyopic patients seeking a laser surgical solution for the management of their refractive error.  

  • Nabila Jones PhD MCOptom FHEA Dip (TP) IP, Irene Sisó-Fuertes PhD MSc, Amir Hamid BMedSci FRCOphth Cert LRS and Clare O’Donnell PhD MBA MCOptom FBCLA FAAO are based at the Optegra Eye Sciences, Optegra Eye Hospital, Manchester, UK 

  

References

  1. Zandian, M, Mehrjerdi, MAZ, Mohebbi, M. (2018). Review of Static Approaches to Surgical Correction of Presbyopia (vol 12, pg 413, 2017). Journal of Ophthalmic & Vision Research, 13(2), 215-215. doi:10.4103/2008-322x.229639 
  2. Gil-Cazorla, R, Shah, S, & Naroo, SA. (2016). A review of the surgical options for the correction of presbyopia. British Journal of Ophthalmology, 100(1), 62-70. doi:10.1136/bjophthalmol-2015-306663 
  3. Charman, WN. (2014). Developments in the correction of presbyopia II: surgical approaches. Ophthalmic & Physiological Optics, 34(4), 397-426. doi:10.1111/opo.12129 
  4. Reinstein, DZ, Carp, GI, Archer, TJ, & Gobbe, M. (2012). LASIK for presbyopia correction in emmetropic patients using aspheric ablation profiles and a micro-monovision protocol with the Carl Zeiss Meditec MEL 80 and VisuMax. Journal of Refractive Surgery, 28(8), 531-541. doi:10.3928/1081597x-20120723-01 
  5. Reinstein, DZ, Archer, TJ, & Gobbe, M. (2011). LASIK for myopic astigmatism and presbyopia using non-linear aspheric micro-monovision with the Carl Zeiss Meditec MEL 80 Platform. Journal of Refractive Surgery, 27(1), 23-37. doi:10.3928/1081597x-20100212-04 
  6. Reinstein, DZ, Couch, DG, & Archer, TJ. (2009). LASIK for hyperopic astigmatism and presbyopia using micro-monovision with the Carl Zeiss Meditec MEL80 platform. Journal of Refractive Surgery, 25(1), 37-58. doi:10.3928/1081597x-20090101-07 
  7. Falcon, C, Norero Martínez, M, & Sancho Miralles, Y. (2015). [Laser Blended Vision for presbyopia: Results after 3 years]. Journal Francaise Ophtalmologie, 38(5), 431-439. doi:10.1016/j.jfo.2015.02.002 
  8. Craig, JP, Nichols, KK, Akpek, EK, Caffery, B, Dua, HS, Joo, CK, . . . Stapleton, F. (2017). TFOS DEWS II Definition and Classification Report. Ocular Surface, 15(3), 276-283. doi:10.1016/j.jtos.2017.05.008 
  9. Friedman, NJ. (2010). Impact of dry eye disease and treatment on quality of life. Current Opinion in Ophthalmology, 21(4), 310-316. doi:10.1097/ICU.0b013e32833a8c15 
  10. Machalinska, A, Zakrzewska, A, Adamek, B, Safranow, K, Wiszniewska, B, Parafiniuk, M, & Machalinski, B. (2015). Comparison of morphological and functional meibomian gland characteristics between daily contact lens wearers and nonwearers. Cornea, 34(9), 1098-1104. doi:10.1097/ico.0000000000000511