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 Table of Contents  
Year : 2021  |  Volume : 1  |  Issue : 3  |  Page : 568-570

Subthreshold micropulse laser treating residual macular subretinal fluid after rhegmatogenous retinal detachment surgery: A case report

Department B, Institut Hedi Rais d'ophtalmologie de Tunis, Tunis; Faculté de médecine de Tunis, Université de Tunis – El Manar, Tunisia

Date of Submission25-Aug-2020
Date of Acceptance04-Mar-2021
Date of Web Publication02-Jul-2021

Correspondence Address:
Dr. Khaled El Matri
Institut Hedi Rais d'ophtalmologie de Tunis, Department B, 1006 Tunis
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijo.IJO_2728_20

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We report the effect of micropulse laser (MPL) treating a case of residual subretinal fluid (SRF) after rhegmatogenous retinal detachment (RRD) surgery. A 38-year-old male patient presenting with residual SRF 6 months following RRD surgery. Initial central macular thickness (CMT) was 243 μm. A 3 × 3 MPL macular grid was performed with moderate reduction of SRF (CMT = 191 μm). Five months following second MPL session, we noted a complete resolution of SRF (CMT = 98 μm) and fundus autofluorescence did not show any laser scare. Micropulse laser might represent a new non-invasive efficient treatment for residual SRF after RDD surgery. MPL effect seemed to be delayed and close follow-up was necessary.

Keywords:  Micropulse laser, residual subretinal fluid, rhegmatogenous retinal detachment

How to cite this article:
El Matri K, Falfoul Y, Chaker N, Chebil A, Bouraoui R, El Matri L. Subthreshold micropulse laser treating residual macular subretinal fluid after rhegmatogenous retinal detachment surgery: A case report. Indian J Ophthalmol Case Rep 2021;1:568-70

How to cite this URL:
El Matri K, Falfoul Y, Chaker N, Chebil A, Bouraoui R, El Matri L. Subthreshold micropulse laser treating residual macular subretinal fluid after rhegmatogenous retinal detachment surgery: A case report. Indian J Ophthalmol Case Rep [serial online] 2021 [cited 2021 Jul 29];1:568-70. Available from: https://www.ijoreports.in/text.asp?2021/1/3/568/320009

Rhegmatogenous retinal detachment (RRD) surgery can be followed by non-resolution of subretinal fluid (SRF). Since chronic SRF does sometimes absorb spontaneously over time,[1] most surgeon believe that it should be managed by observation.[2] However, other therapeutic approaches have been proposed to accelerate the resolution of SRF.

Subthreshold micropulse laser (MPL) induces selective photostimulation of the retinal pigment epithelium (RPE) pumping function, promoting the recovery and restoration of the outer blood–retinal barrier and the resorption of SRF.[3]

Our aim was to investigate the effect of MPL in the treatment of a long-standing residual macular SRF after RRD surgery.

  Case Report Top

A 38-year-old male patient with history of RRD in his amblyopic right eye treated with cryotherapy and scleral buckling was followed post operatively for persistent SRF, with non-significant improvement of his best-corrected visual acuity (BCVA). Six months following surgery, chronic residual macular SRF was still present and BCVA was stable at 0.05.

Structural B-Scan optical coherence tomography (OCT) (Topcon, DRI OCT Triton, Japan) showed substantial SRF accumulation. SRF height (SRFH) was 181 μm and central macular thickness (CMT) was 243 μm. Initial subfoveal choroidal thickness was 199 μm [Figure 1]a.
Figure 1: Follow-up of residual subretinal fluid treated with micropulse laser. Baseline OCT (a): Substantial subfoveal fluid accumulation. SRFH = 181 μm (arrow) and CMT = 243 μm. Baseline FAF (b): Patchy autofluorescence of the posterior pole. Two hyperautofluorescent lines of demarcation. Control OCT, 8 weeks after 1st MPL (c): Moderate reduction of SRF accumulation. SRFH = 130 μm (arrow) and CMT = 191 μm. Control OCT, 8 weeks after 2nd MPL (d): Near-complete resolution of fluid accumulation with persistent trace SRF. SRFH = 51 μm (arrow) and CMT = 109 μm. Control OCT, 5 months after second MPL (e): Complete resolution of SRF with sequalae central photoreceptor atrophy (arrowhead). CMT = 98 μm. Control FAF, 5 months after second MPL (f): No laser macular scares

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On blue fundus autofluorescence (FAF) (Spectralis HRA2, Heidelberg, Germany), we noted areas of patchy autofluorescence in the posterior pole in sites of prior detachment and two hyperautofluorescent lines of demarcation [Figure 1]b.

Patient was treated with macular MPL (Iridex IQ 577 nm yellow laser, Mountain View, CA, USA). For power level titration; we set laser in traditional settings, placing a test spot (spot size = 100 μm, exposure duration = 0.1 second) on healthy retina in the nasal area. We start with 100 mW power while gradually increasing laser power until threshold value is reached with a thermal burn (whitening). We then switch the laser to micropulse mode, doubling the spot size and exposure duration, and multiplying laser power by 4. Macular MPL was performed with a high density, no spacing application of spots, using a 3 × 3 grid (spot size = 200 μm, wavelength = 577 nm, duty cycle = 5%, exposure duration = 0.2 second, power titration = 460 mW, 125 impacts).

MPL was applied with laser impacts covering the entire area with SRF.

Swept source OCT and FAF were performed before treatment and after each MPL session.

After 8 weeks, BCVA was stable (0.05) but OCT showed reduction of SRF; SRFH decreasing to 130 μm and CMT decreasing to 191 μm. Besides, SFCT also decreased to 176 μm [Figure 1]c.

We then performed a second macular grid using same MPL parameters and 8 weeks after second MPL session, patient reported a visual improvement with BCVA increasing to 0.1. OCT showed near-complete fluid resolution with persistent trace SRF. SRFH was 51 μm, CMT was 109 μm and SFCT was 166 μm [Figure 1]d.

Five months after second MPL session, OCT showed complete resolution of SRF and CMT was 98 μm (60% reduction), but sequelae central photoreceptor atrophy was noted. SFCT was lowered to 151 μm (24% reduction) [Figure 1]e. BCVA was stable at 0.1 and FAF did not show any sign of laser macular scares [Figure 1]f. Evolution of SRFH, CMT, SFCT and their reduction rates are shown in [Table 1].
Table 1: Evolution of SRFH, CMT and SFCT following MPL treatment

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  Discussion Top

We reported here a successful case of micropulse laser treating persistent chronic subretinal fluid after RRD surgery. We performed a subthreshold micropulse laser 577 nm as a macular grid treating residual macular SRF, with good anatomical and functional outcomes.

MPL might represent a new efficient therapeutic approach for residual SRF after RRD surgery. The site of action of MPL is supposed to be at the level of the RPE[4] with a photostimulation of foveal and parafoveal RPE cells, enhancing their pumping function to reabsorb the SRF, without the retinal damage observed in classical laser photocoagulation.[5] In our case, we noticed a progressive reduction in SFCT following MPL sessions, concomitant to SRF reduction; final SFCT being 24% thinner than initially. Thus, MPL might have a supplementary action on choroidal thickness and choroidal permeability, consolidating its effect on SRF reabsorption. This hypothesis is consistent with a previous study that showed comparable effects of MPL and photodynamic therapy on SFCT reduction in central serous chorioretinopathy patients.[6]

MPL has been proven to be safe, painless and successful in absorption of SRF in chronic macular diseases.[7],[8] In recent studies, MPL was demonstrated to be effective anatomically and functionally treating persistent SRF after RDD surgery.[9],[10] Esposti et al.[9] reported a case series of eleven eyes with residual subfoveal fluid after RRD surgery treated with micropulse yellow laser. They noted a visual improvement and disappearance of subfoveal fluid with a restored macular profile in 9 eyes (82%). Landa[10] reported a case of persistent SRF following RRD surgery (retinal pneumopexy + C3F8 gas injection) treated with MPL 577 nm, resulting in a complete resolution of fluid and retinal detachment. The improvement in SRF and clinical symptoms were started two weeks following MPL session and SRF had completely resolved within four months after application of MPL.

In our case, anatomical response was noticed 8 weeks after first MPL session with moderate reduction in SRFH (35%). Anatomical changes were unlikely due to natural evolution since it was a long-standing SRF with an unchanged SRFH during 6 months following RDD surgery, while near-complete resolution of SRF (72%) was observed 8 weeks following second MPL application and complete resolution was noted within 5 months. The anatomical effect of MPL seemed to be delayed and a close follow-up was necessary. Functional effect of MPL was even more delayed and visual improvement was noted only 8 weeks following second MPL application.

Our patient reported a history of amblyopia in his right eye explaining the baseline BCVA of 0.05. Visual acuity improved to 0.1 after MPL therapy and remained stable during follow-up. BCVA improvement was not dramatic in our case, but considering the fact that the eye was amblyopic, the improvement was considered significant. Besides, the patient noticed the functional improvement and was satisfied of the procedure outcome. Moreover, central photoreceptor atrophy was present on structural OCT after reapplication of the long-standing subfoveal detachment. We know that photoreceptors apoptosis can occur in chronic retinal detachments with a negative impact on final functional outcomes. The longer SRF will be present under the fovea, the worse functional visual outcome might be achieved.[11]

  Conclusion Top

Micropulse laser represents a new non-invasive, painless and efficient treatment for residual subfoveal fluid after retinal detachment surgery, with a lasting therapeutic response and the possibility of retreatment. Since MPL is a safe procedure without any risk of neuro-retinal damage, it should be offered as an early therapeutic option before the onset of central photoreceptors atrophy following chronic foveal detachment.

A comparative case study with a larger series of patients is required for the validity of the conclusion.


The authors thank Iridex company for the micropulse laser 577 nm device used in this case, in our department.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

This case was presented as a poster in “MACULART” meeting 2019, in Paris. The abstract was posted on 2019.maculart-meeting.com.

Conflicts of interest

There are no conflicts of interest.

  References Top

Hagimura N, Iida T, Suto K, Kishi S. Persistent foveal retinal detachment after successful rhegmatogenous retinal detachment surgery. Am J Ophthalmol 2002;133:516-20.  Back to cited text no. 1
Desatnik H, Alhalel A, Treister G, Moisseiev J. Management of persistent loculated subretinal fluid after pneumatic retinopexy. Br J Ophthalmol 2001;85:189-92.  Back to cited text no. 2
Yadav N, Jayadev C, Rajendran A, Nagpal M. Recent developments in retinal lasers and delivery systems. Indian J Ophthalmol 2014;62;62:50-4.  Back to cited text no. 3
Luttrull JK, Sinclair SH. Safety of transfoveal subthreshold diode micropulse laser for fovea-involving diabetic macular edema in eyes with good visual acuity. Retina 2014;34:2010-20.  Back to cited text no. 4
Brader HS, Young LHY. Subthreshold diode micropulse laser: A review. Semin Ophthalmol 2016;31:30-9.  Back to cited text no. 5
Ntomoka CG, Rajesh B, Muriithi GM, Goud A, Chhablani J. Comparison of photodynamic therapy and navigated microsecond laser for chronic central serous chorioretinopathy. Eye (Lond) 2018;32:1079-86.  Back to cited text no. 6
Yadav N, Jayadev C, Mohan A, Vijayan P, Battu R, Dabir S, et al. Subthreshold micropulse yellow laser (577 Nm) in chronic central serous chorioretinopathy: Safety profile and treatment outcome. Eye (Lond) 2015;29:258-64.  Back to cited text no. 7
Shah S, Hariprasad S. Application of micropulse lasers in treating macular diseases. Ophthalmic Surg Lasers Imaging Retina 2016;47:985-90.  Back to cited text no. 8
Esposti G, Esposti P, Fruschelli M, Hadjistilianou T. Photostimulation with subthreshold yellow micropulsed laser for chronic residual subfoveal rhegmatogenous retinal detachment after surgery. Acta Ophthalmol 2017;95. doi: 10.1111/j. 1755-3768.2017.01114.  Back to cited text no. 9
Landa G. Micropulse laser for persistent sub-retinal fluid in a patient previously treated for rhegmatogenous retinal detachment. Med Hypothesis Discov Innov Ophthalmol J 2018;7.  Back to cited text no. 10
Hisatomi T, Sakamoto T, Goto Y, Yamanaka I, Oshima Y, Hata Y, et al. Critical role of photoreceptor apoptosis in functional damage after retinal detachment. Curr Eye Res 2002;24:161-72.  Back to cited text no. 11


  [Figure 1]

  [Table 1]


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