Subthreshold laser treatment in retinal diseases: a mini review.

PURPOSE: To summarize the mechanism and the clinical applications of subthreshold laser (STL) in retinal practice. Subthreshold or "non-destructive" laser includes all types of laser treatments that produce minimal or no damage to the tissues and no visible signs after application. METHODS: A descriptive review of articles from literature databases (PubMed, Medline, Embase, Cochrane, Web of Science) published before August 2023, which discuss current STL treatments of retinal diseases. RESULTS: This review provides evidence for STL as a treatment option for central serous chorioretinopathy, diabetic retinopathy, age-related macular degeneration, macular edema due to retinal vein occlusion, and other maculopathies. In most published reports, STL has shown a therapeutic effect without damage to the underlying tissue. CONCLUSION: Subthreshold laser treatment has shown safety and efficacy in the management of some retinal and macular diseases. Stimulation of the retinal pigment epithelium without destroying adjacent neuroretina has been shown to be sufficient in inducing retinal repair in many clinical cases. Recent research and clinical studies continue to explore the mechanisms and improving therapeutic benefits of this technology as well as extend the range of retinal disorders treatable by this modality.

Long-term follow-up demonstrates change in conformation shape of the focal choroidal excavation lesions.

PURPOSE: This study aims to present long-term observation of 5 eyes with focal choroidal excavation (FCE), focusing on morphological changes in conformity of the lesion. METHODS: A retrospective case series was conducted, including 5 eyes of 5 patients with FCE. The study utilized multimodal imaging including color fundus photography, optical coherence tomography (OCT), enhanced depth imaging OCT (EDI-OCT), fundus fluorescein angiography (FFA), fundus autofluorescence (FAF), red free imaging, and OCT angiography. RESULTS: The mean age at diagnosis was 51 ± 10.65 years, with a mean follow-up period 37 ± 13.59 months. All cases were unilateral, with 1 presenting FCE as an isolated lesion, and one patient exhibiting 2 FCEs in one eye. The mean choroidal thickness measured by EDI-OCT was 268.2 ± 63.39 µm in the affected eye. One patient displayed choroidal thickening and pachyvessels. Of the 5 eyes, one had conforming and 4 non-conforming FCE. We observed a conversion in conformity in all patients, with 4 cases transitioning from non-conforming FCE to conforming type (3 spontaneously, 1 treatment-induced). In conforming FCE, a hyporeflective space appeared twice between neuroretina and retinal pigment epithelium with spontaneous regression. CONCLUSION: We observed change in shape from the conforming to non-conforming FCE and vice versa in all patients. We consider this small change in the hyporeflective space as non-pathologic and clinically insignificant.

Laser-Based Therapy Approaches in the Retina: A Review of Micropulse Laser Therapy for Diabetic Retinopathy.

PURPOSE: This review aims to elucidate the mechanisms and clinical utility of subthreshold micropulse laser (SML) therapy in the context of retinal care. Subthreshold or "nondestructive" laser therapy encompasses treatment modalities that induce minimal or no harm to retinal or choroidal tissue and leave no visible sings post-application, while achieving clinical efficacy. METHODS: A comprehensive review of literature sourced from databases including PubMed, Medline, Embase, Cochrane, and Web of Science was conducted, focusing on articles published before February 2024, and discussing the contemporary use of SML therapy in treating diabetic retinopathy (DR). RESULTS: The review presents evidence from scientific literature supporting SML therapy as a viable therapeutic approach for management of DR. Across numerous studies, SML therapy has demonstrated safety and additional therapeutic efficacy without causing damage to underlying retinal tissue. CONCLUSION: Subthreshold laser treatment emerges as a safe strategy for addressing DR. Numerous studies have shown its additional efficacy to anti-VEGF pharmacotherapy, which is the currently approved monotherapy for complications of DR. Ongoing research and clinical investigations aim to further elucidate the mechanisms and optimize the therapeutic advantages of this technology.

The impact of artificial intelligence on retinal disease management: Vision Academy retinal expert consensus.

PURPOSE OF REVIEW: The aim of this review is to define the "state-of-the-art" in artificial intelligence (AI)-enabled devices that support the management of retinal conditions and to provide Vision Academy recommendations on the topic. RECENT FINDINGS: Most of the AI models described in the literature have not been approved for disease management purposes by regulatory authorities. These new technologies are promising as they may be able to provide personalized treatments as well as a personalized risk score for various retinal diseases. However, several issues still need to be addressed, such as the lack of a common regulatory pathway and a lack of clarity regarding the applicability of AI-enabled medical devices in different populations. SUMMARY: It is likely that current clinical practice will need to change following the application of AI-enabled medical devices. These devices are likely to have an impact on the management of retinal disease. However, a consensus needs to be reached to ensure they are safe and effective for the overall population.

Current status and practical considerations of artificial intelligence use in screening and diagnosing retinal diseases: Vision Academy retinal expert consensus.

PURPOSE OF REVIEW: The application of artificial intelligence (AI) technologies in screening and diagnosing retinal diseases may play an important role in telemedicine and has potential to shape modern healthcare ecosystems, including within ophthalmology. RECENT FINDINGS: In this article, we examine the latest publications relevant to AI in retinal disease and discuss the currently available algorithms. We summarize four key requirements underlining the successful application of AI algorithms in real-world practice: processing massive data; practicability of an AI model in ophthalmology; policy compliance and the regulatory environment; and balancing profit and cost when developing and maintaining AI models. SUMMARY: The Vision Academy recognizes the advantages and disadvantages of AI-based technologies and gives insightful recommendations for future directions.

DIRECT MACULAR HOLE MANIPULATION RESULTS IN HIGH SUCCESS RATE IN SECONDARY MACULAR HOLE REPAIR.

PURPOSE: To investigate closure rates and functional outcomes of surgery for refractory and recurrent macular holes (MHs) in a real-world setting. METHODS: Retrospective review of secondary MH surgeries. RESULTS: A total of 72 eyes from 72 patients were included. Eyes had a mean of 1.51 surgeries before inclusion into this study with a mean MH size of 762 µ m and a mean baseline logarithm of the minimum angle of resolution best-corrected visual acuity of 1.11 (∼20/260 Snellen). Closure rates were 89.3% for tissue transplantation, 77.3% for internal limiting membrane (ILM) flaps, 92.9% for MH manipulation, and 12.5% for repeat ILM peeling ( P < 0.05). Best-corrected visual acuity changes in logarithm of the minimum angle of resolution from baseline to postoperative month six were +0.29 for ILM peeling alone (15 Early Treatment Diabetic Retinopathy Study letters worse), -0.39 for MH manipulation (20 Early Treatment Diabetic Retinopathy Study letters improved), -0.23 for tissue transplantation (13 Early Treatment Diabetic Retinopathy Study letters improved), and -0.2 for ILM flaps (10 Early Treatment Diabetic Retinopathy Study letters improved; P < 0.05). CONCLUSION: Secondary MH closure is possible using various surgical techniques with acceptable anatomical closure rates. Repeat ILM peeling is associated with the lowest closure rates and poorest functional results. To distinguish between techniques would require a large sample size of approximately 750 eyes.

Retinal Findings in Haemorrhagic Destruction of the Brain, Subependymal Calcification, and Congenital Cataracts (HDBSCC): Case Report and Review.

We describe a child from a consanguineous family born with a rare autosomal recessive disorder affecting junctional adhesion molecule 3 (JAM3) causing profound neurological and ophthalmological injury known as haemorrhagic brain destruction, subependymal calcifications, and congenital cataracts (HDBSCC; MIM# 613730). She was the product of an unremarkable pregnancy and was born near to term but was noted shortly after birth to have congenital cataracts, poor vision, increased muscle tone, seizures, and developmental delay. Her older sister had an identical syndrome and had previously been documented to have homozygous mutations in JAM3. Examination in our patient, although difficult because of bilateral central cataracts, revealed very poor vision, attenuated retinal vessels, optic atrophy, and a retinal haemorrhage in the right eye, implying that abnormal development of the retinas and/or optic nerves may at times play a significant role in the poor vision noted in children with HDBSCC.

Lanosterol reverses protein aggregation in cataracts.

The human lens is comprised largely of crystallin proteins assembled into a highly ordered, interactive macro-structure essential for lens transparency and refractive index. Any disruption of intra- or inter-protein interactions will alter this delicate structure, exposing hydrophobic surfaces, with consequent protein aggregation and cataract formation. Cataracts are the most common cause of blindness worldwide, affecting tens of millions of people, and currently the only treatment is surgical removal of cataractous lenses. The precise mechanisms by which lens proteins both prevent aggregation and maintain lens transparency are largely unknown. Lanosterol is an amphipathic molecule enriched in the lens. It is synthesized by lanosterol synthase (LSS) in a key cyclization reaction of a cholesterol synthesis pathway. Here we identify two distinct homozygous LSS missense mutations (W581R and G588S) in two families with extensive congenital cataracts. Both of these mutations affect highly conserved amino acid residues and impair key catalytic functions of LSS. Engineered expression of wild-type, but not mutant, LSS prevents intracellular protein aggregation of various cataract-causing mutant crystallins. Treatment by lanosterol, but not cholesterol, significantly decreased preformed protein aggregates both in vitro and in cell-transfection experiments. We further show that lanosterol treatment could reduce cataract severity and increase transparency in dissected rabbit cataractous lenses in vitro and cataract severity in vivo in dogs. Our study identifies lanosterol as a key molecule in the prevention of lens protein aggregation and points to a novel strategy for cataract prevention and treatment.

SENSITIVITY AND SPECIFICITY OF MULTISPECTRAL IMAGING FOR POLYPOIDAL CHOROIDAL VASCULOPATHY.

PURPOSE: To evaluate the sensitivity and specificity of multispectral imaging (MSI), a noninvasive imaging technique composed of a series of monochromatic scanning light, for polypoidal choroidal vasculopathy (PCV). METHODS: This was a prospective observational study. Polypoidal lesions on MSI are defined by oval or lobular hyperreflective oval lesion with dark hyporeflective center. Branching vascular networks on MSI is featured by hyperreflective interlacing signal. Detection sensitivity and specificity of polypoidal lesions was compared with indocyanine green angiography, whereas sensitivity and specificity of branching vascular networks, subretinal fluid, and pigment epithelium detachment were compared with optical coherence tomography. RESULTS: Among 67 eyes, 38 eyes (56.7%) were diagnosed with PCV, 7 eyes (10.4%) with neovascular age-related macular degeneration, 13 eyes (19.4%) with central serous chorioretinopathy, 6 eyes (9.0%) with pathological myopia, and 3 eyes (4.5%) with idiopathic choroidal neovascularization. Compared with indocyanine green angiography, the sensitivity and specificity for diagnosing PCV by MSI alone was 84.21% and 93.10%, respectively, and the positive predictive value and the negative predictive value for PCV by MSI was 94.12% and 81.82%, respectively. The sensitivity and specificity for detecting polypoidal lesions were 84.21% and 93.10% compared with indocyanine green angiography. Compared with optical coherence tomography, the sensitivity and specificity for detecting branching vascular networks were 95.83% and 88.37%, for the subretinal fluid were 76.92% and 86.67%, and for the pigment epithelium detachment were 91.11% and 90.91%, respectively. CONCLUSION: Multispectral imaging allowed noninvasive visualization of polypoidal lesions and branching vascular networks and may serve as a new diagnostic option for PCV.

The genetic landscape of inherited eye disorders in 74 consecutive families from the United Arab Emirates.

Genetic eye diseases are phenotypically and genetically heterogeneous, affecting 1 in 1,000 people worldwide. This prevalence can increase in populations where endogamy is a social preference, such as in Arab populations. A retrospective consecutive cohort of 91 patients from 74 unrelated families affected with non-syndromic and syndromic inherited eye disease presenting to the ocular genetics service at Moorfields Eye Hospitals United Arab Emirates (UAE) between 2017 and 2019, underwent clinically accredited genetic testing using targeted gene panels. The mean ± SD age of probands was 27.4 ± 16.2 years, and 45% were female (41/91). The UAE has a diverse and dynamic population, and the main ethnicity of families in this cohort was 74% Arab (n = 55), 8% Indian (n = 6) and 7% Pakistani (n = 5). Fifty-six families (90.3%) were genetically solved, with 69 disease-causing variants in 40 genes. Fourteen novel variants were detected with large deletions in CDHR1 and TTLL5, a multiexon (1-8) duplication in TEAD1 and 11 single nucleotides variants in 9 further genes. ABCA4-retinopathy was the most frequent cause accounting for 21% of cases, with the confirmed UAE founder mutation c.5882G>A p.(Gly1961Glu)/c.2570T>C p.(Leu857Pro) in 25%. High diagnostic yield for UAE patients can guide prognosis, family decision-making, access to clinical trials and approved treatments.

Novel observations in choroidal osteoma by multispectral imaging: a pilot case series.

PURPOSE: To identify novel tumor-specific features of ossification by using multispectral imaging (MSI) in patients diagnosed with choroidal osteoma. METHODS: Six eyes of 5 patients previously diagnosed with choroidal osteoma by ocular ultrasonography and orbital computerized tomography were observed with multispectral imaging (MSI). Traditional multimodal imaging, including color fundus photograph (CFP) and enhanced depth-imaging-optical coherence tomography (EDI-OCT), fundus autofluorescence (FAF), indocyanine green angiography/fundus fluorescein angiography (ICGA/FFA), was performed. Osseous features detected by MSI such as calcification and decalcification were characterized and compared with other imaging modalities. RESULTS: In all 3 eyes with calcified choroidal osteoma (100%), MSI featured by the homogeneous reflectance in 550 nm but the beehive appearance in 600-680 nm and homogenous hyper-reflectance in 780-850 nm', indicating the compact bone in the outer layers and bone trabecula in the middle layer (Sandwich sign). The pigmentary change showed high agreement between MSI and FAF. In other 3 eyes with extensive decalcification, MSI was able to differentiate the inactive portion of the osteoma from the decalcified area. The inactive portion was characterized by geographic hyper-reflective islands with higher reflectivity border (floating island sign). Decalcified portion was featured by increased definition and reflectivity from osteoma. Partial decalcification and total decalcification can be differentiated in one decalcifying eye (33.3%). MSI revealed better the presence and border of the osteoma compared with FFA, FAF and MC (100%) in all six eyes in our study. CONCLUSIONS: MSI presented characteristic osseous-related features of choroidal osteoma, providing clear evidence for differentiating osteoblastic and osteoclastic regions and noncalcifying regions. It can contribute to en-face visualization of choroidal osteomas at different stages, providing new insight into the spectrum behavior of CO.

Sickle cell retinopathy. A focused review.

PURPOSE: To provide a focused review of sickle cell retinopathy in the light of recent advances in the pathogenesis, multimodal retinal imaging, management of the condition, and migration trends, which may lead to increased prevalence of the condition in the Western world. METHODS: Non-systematic focused literature review. RESULTS: Sickle retinopathy results from aggregation of abnormal hemoglobin in the red blood cells in the retinal microcirculation, leading to reduced deformability of the red blood cells, stagnant blood flow in the retinal precapillary arterioles, thrombosis, and ischemia. This may be precipitated by hypoxia, acidosis, and hyperosmolarity. Sickle retinopathy may result in sight threatening complications, such as paracentral middle maculopathy or sequelae of proliferative retinopathy, such as vitreous hemorrhage and retinal detachment. New imaging modalities, such as wide-field imaging and optical coherence tomography angiography, have revealed the microstructural features of sickle retinopathy, enabling earlier diagnosis. The vascular growth factor ANGPTL-4 has recently been identified as a potential mediator of progression to proliferative retinopathy and may represent a possible therapeutic target. Laser therapy should be considered for proliferative retinopathy in order to prevent visual loss; however, the evidence is not very strong. With recent development of wide-field imaging, targeted laser to ischemic retina may prove to be beneficial. Exact control of intraoperative intraocular pressure, including valved trocar vitrectomy systems, may improve the outcomes of vitreoretinal surgery for complications, such as vitreous hemorrhage and retinal detachment. Stem cell transplantation and gene therapy are potentially curative treatments, which may prevent retinopathy. CONCLUSIONS: There is lack of evidence regarding the optimal management of sickle retinopathy. Further study is needed to determine if recent progress in the understanding of the pathophysiology and diagnosis of sickle retinopathy may translate into improved management and outcome.

Retinal detachment and uveitis at a tertiary center over 10 years: the King Khaled Eye Specialist Hospital (KKESH) Uveitis Survey Study Group.

PURPOSE: To evaluate the frequency, etiology, treatment, and visual prognosis of retinal detachment (RD) in patients with uveitis. METHODS: A retrospective review was performed in 707 consecutive patients (1042 eyes) with uveitis, of whom 97 (13.7%) (157 eyes [15.1%]) had RD. RESULTS: There were 126 (12.1%) eyes with exudative retinal detachment (ERD), 16 (1.5%) with tractional retinal detachment (TRD), and 15 (1.4%) with rhegmatogenous retinal detachment (RRD). Panuveitis was most commonly associated with RD (144 (91.1%) eyes). Infectious causes were more common in RRD, and non-infectious etiologies were most common in ERD and TRD. Oral prednisone was the initial therapy in ERD. Additionally, in these cases, cyclosporine was prescribed most frequently (47.1% patients), followed by azathioprine (26.4% patients). Fourteen (87.5%) eyes with TRD and all RRD cases underwent surgery. In patients with ERD, the mean best-corrected visual acuity (BCVA) was 1.1 ± 0.7 LogMAR at baseline and 0.6 ± 0.2 LogMAR at last visit (p = 0.001). In patients with TRD, mean BCVA was 0.7 ± 0.4 LogMAR at baseline and 0.6 ± 0.4 LogMAR at last visit (p = 0.056). In patients with RRD, mean BCVA was 1.6 ± 0.9 LogMAR at baseline and 20 1.3 ± 0.9 LogMAR at last visit (p = 0.185). CONCLUSION: In Saudi Arabia, ERD is observed in 12.1% of the eyes with uveitis, and less than 2% of eyes had TRD or RRD. Visual prognosis is usually good after ERD. Infection is the most frequent cause of RRD associated with uveitis and the visual prognosis is poor.

INTRAVITREAL DEXAMETHASONE IMPLANT IN RETINITIS PIGMENTOSA-RELATED CYSTOID MACULAR EDEMA.

PURPOSE: To report the clinical outcome after intravitreal dexamethasone implant in patients with retinitis pigmentosa and cystoid macular edema. METHODS: Multicenter retrospective case series of eyes with retinitis pigmentosa and cystoid macular edema that underwent intravitreal dexamethasone implant. Primary outcome measures were best-corrected visual acuity in LogMAR and central macular thickness. Statistical analyses used two-tailed comparison with Wilcoxon signed-rank test. RESULTS: There were a total of 45 eyes from 34 patients with a mean age of 32.7 years (range 16-57) and mean follow-up of 15.5 ± 13.0 months. At Month 3 after the first injection, mean initial best-corrected visual acuity improved from 0.61 ± 0.38 (20/81) to 0.37 ± 0.16 (20/47) (P = 0.012), whereas mean central macular thickness (µm) decreased from 506 ± 288 µm to 311.7 ± 71.6 µm (P < 0.001) and mean intraocular pressure increased from 15.7 ± 2.3 mmHg to 19.8 ± 11.0 mmHg (P = 0.01). Fourteen eyes had multiple injections (1-7 reinjections) at a mean interval of 6 months. Treatment effect was durable with multiple injections, but with seven eyes developing visually significant cataracts. CONCLUSION: Best-corrected visual acuity improved up to 4 months in around half of the eyes. Eyes that benefited the most were pseudophakic, steroid nonresponsive, with large initial central macular thickness, and profuse fluorescein dye leakage.

Identification of Novel Deletions as the Underlying Cause of Retinal Degeneration in Two Pedigrees.

Retinal dystrophies are a phenotypically and genetically complex group of conditions. Because of this complexity, it can be challenging in many families to determine the inheritance based on pedigree analysis alone. Clinical examinations were performed and blood samples were collected from a North American (M1186) and a consanguineous Pakistani (PKRD168) pedigree affected with two different retinal dystrophies (RD). Based on the structure of the pedigrees, inheritance patterns in the families were difficult to determine. In one family, linkage analysis was performed with markers on X-chromosome. In the second family, whole-exome sequencing (WES) was performed. Subsequent Sanger sequencing of genes of interest was performed. Linkage and haplotype analysis localized the disease interval to a 70 Mb region on the X chromosome that encompassed RP2 and RPGR in M1186 . The disease haplotype segregated with RD in all individuals except for an unaffected man (IV:3) and his affected son (V:1) in this pedigree. Subsequent analysis identified a novel RPGR mutation (p. Lys857Glu fs221X) in all affected members of M1186 except V:1. This information suggests that there is an unidentified second cause of retinitis pigmentosa (RP) within the family. A novel two-base-pair deletion (p. Tyr565Ter fsX) in CHM (choroideremia) was found to segregate with RD in PKRD168. This paper highlights the challenges of interpreting family history in families with RD and reports on the identification of novel mutations in two RD families.

Genetic analysis of 10 pedigrees with inherited retinal degeneration by exome sequencing and phenotype-genotype association.

Our purpose was to identify causative mutations and characterize the phenotype associated with the genotype in 10 unrelated families with autosomal recessive retinal degeneration. Ophthalmic evaluation and DNA isolation were carried out in 10 pedigrees with inherited retinal degenerations (IRD). Exomes of probands from eight pedigrees were captured using Nimblegen V2/V3 or Agilent V5+UTR kits, and sequencing was performed on Illumina HiSeq. The DHDDS gene was screened for mutations in the remaining two pedigrees with Ashkenazi Jewish ancestry. Exome variants were filtered to detect candidate causal variants using exomeSuite software. Segregation and ethnicity-matched control sample analysis were performed by dideoxy sequencing. Retinal histology of a patient with DHDDS mutation was studied by microscopy. Genetic analysis identified six known mutations in ABCA4 (p.Gly1961Glu, p.Ala1773Val, c.5461-10T>C), RPE65 (p.Tyr249Cys, p.Gly484Asp), PDE6B (p.Lys706Ter) and DHDDS (p.Lys42Glu) and ten novel potentially pathogenic variants in CERKL (p.Met323Val fsX20), RPE65 (p.Phe252Ser, Thr454Leu fsX31), ARL6 (p.Arg121His), USH2A (p.Gly3142Ter, p.Cys3294Trp), PDE6B (p.Gln652Ter), and DHDDS (p.Thr206Ala) genes. Among these, variants/mutations in two separate genes were observed to segregate with IRD in two pedigrees. Retinal histopathology of a patient with a DHDDS mutation showed severe degeneration of retinal layers with relative preservation of the retinal pigment epithelium. Analysis of exome variants in ten pedigrees revealed nine novel potential disease-causing variants and nine previously reported homozygous or compound heterozygous mutations in the CERKL, ABCA4, RPE65, ARL6, USH2A, PDE6B, and DHDDS genes. Mutations that could be sufficient to cause pathology were observed in more than one gene in one pedigree.

Teleophthalmology image-based navigated retinal laser therapy for diabetic macular edema: a concept of retinal telephotocoagulation.

BACKGROUND: To determine the feasibility and efficacy of a retinal telephotocoagulation treatment plan for diabetic macular edema. METHODS: Prospective, interventional cohort study at two clinical sites. Sixteen eyes of ten subjects with diabetic macular edema underwent navigated focal laser photocoagulation using a novel teleretinal treatment plan. Clinic 1 (King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia) collected retinal images and fundus fluorescein angiogram. Clinic 2 (Palmetto Retina Center, West Columbia, SC, USA) created image-based treatment plans based on which macular laser photocoagulation was performed back at clinic 1. The primary outcome of the study was feasibility of image transfer and performing navigated laser photocoagulation for subjects with diabetic macular edema between two distant clinics. Secondary measures were change in best-corrected visual acuity (BCVA) and central retinal thickness (CRT) by spectral-domain optical coherence tomography at 3 months after treatment. RESULTS: The teleretinal treatment plan was able to be successfully completed in all 16 eyes. The mean logMAR BCVA at baseline was 0.49 ± 0.1, which remained stable (0.45 ± 0.1) 3 months after treatment (p = 0.060). The CRT improved from 290.1 ± 37.6 µm at baseline to 270.8 ± 27.7 µm 3 months after treatment (p = 0.005). All eyes demonstrated improvement in the area of retinal edema after laser photocoagulation, and no eyes demonstrated visual acuity loss 3 months after treatment. CONCLUSION: This study introduces the concept of retinal telephotocoagulation for diabetic macular edema, and demonstrates the feasibility and safety of using telemedicine to perform navigated retinal laser treatments regardless of geographical distance.

OUTCOMES OF PARS PLANA VITRECTOMY IN THE MANAGEMENT OF REFRACTORY AQUEOUS MISDIRECTION SYNDROME.

PURPOSE: To determine the efficacy and complications of pars plana vitrectomy (PPV) and adjunct surgeries for aqueous misdirection refractory to medical therapy. METHODS: A retrospective review of consecutive eyes with refractory aqueous misdirection at the King Khaled Eye Specialist Hospital between 2002 and 2010. Patients underwent two-port and three-port pars plana vitrectomy (PPV) with adjunct procedures including pars plana lensectomy combined with posterior capsulectomy, hyaloido-zonulo-iridectomy, and synechiolysis. Main outcome measures included anatomical success, functional success, and factors associated with the outcomes. RESULTS: Sixty-nine eyes were evaluated over a mean follow-up period of 17.6 ± 3.8 months (3-156 months). Anatomical success was achieved in 62 eyes (90%) and functional success in 54 eyes (78%) that underwent PPV as a primary surgery. The factors associated with the altering misdirected aqueous flow and reducing intraocular pressure significantly associated with a two-line improvement of best-corrected visual acuity included surgical treatment within 4 weeks of presentation (P = 0.004) and preoperative intraocular pressure (P = 0.001). The success of two-port PPV and standard three-port PPV was similar (P = 0.7). The intraoperative and postoperative complications included retinal detachment in two eyes and endophthalmitis in one eye. CONCLUSION: The PPV was effective for managing aqueous misdirection refractory to medical therapy. Two-port or three-port PPV did not change the success rate but early surgery improved both anatomical and functional outcomes.