IntroductionLattice degeneration is a common peripheral retinal degeneration that represents localized of retinal thinning, overlying vitreous liquefaction, and marginal vitreoretinal adhesion. The condition is associated with atrophic retinal holes, retinal tears, and retinal detachments. A common condition, the lattice degeneration is present in 6-8% of the general population though past histologic studies on autopsy suggest a prevalence as high as 10.7% 
Lattice degeneration is most commonly found incidentally on routine ophthalmic examination. However, several classic associations exist:
- Myopia: The prevalence of lattice degeneration is greater in myopic eyes (33% in a study) compared to general population (around 6-10%) which might at least partially explain the increased risk of retinal detachment in myopes.
- Retinal Detachment: Approximately 20 to 30% of patients with a rhegmatogenous retinal detachment (RRD) have lattice degeneration. However, and importantly, the reverse is quite different: in one study, three out of 423 eyes developed clinical retinal detachments and sixteen developed subclinical retinal detachments. Nonetheless, lattice degeneration is frequently cited as a risk factor for development of RRD given its strong association with this entity.
- Hereditary Vitreopathies: Stickler Syndrome may present with unique radial perivascular lattice-like degeneration is often seen in Stickler Syndrome.  This feature is not believed to be congenital, but rather, develops during childhood and progresses throughout life. Wagner Syndrome may also present with lattice degeneration.
The etiology per se of the lattice degeneration is unknown, though theories include developmental anomalies of the internal limiting membrane, embryologic vascular anastomosis, localized retinal ischemia, or the contention that lattice degeneration is a primary vitreopathy leading to the formation of abnormal vitreous traction.
- Retinal thinning
- Vitreous liquefaction overlying the thinned retina
- Tight vitreoretinal adhesion at the margins of the lesion
- Retinal thinning
- Vascular fibrosis
- Neuronal atrophy
- Accumulation of glial material
- Pigmentary changes
- Internal limiting membrane changes
- Lack of basement membrane over the surface of lattice lesions and replacement with glial cells.
It is well documented that lattice degeneration increases the risk of retinal tears or subsequent detachments. This occurs by way of two mechanisms: (1) atrophic retinal hole or (2) retinal tear.
Atrophic Retinal Hole
Atrophic round holes occur within the substance of the lattice lesion and likely represent the end-stage of retinal thinning and subsequent dissolution of tissue.  These holes rarely progress to a clinical retinal detachment though may develop a small cuff of subretinal fluid stemming from the overlying liquefied vitreous. As this cuff typically remains stable over time, it is believed that the overlying liquid vitreous does not communicate with the greater vitreous body. Overall, a small percentage of retinal detachments are caused by lattice degeneration atrophic holes (2.8% from one study). And conversely, the risk of a retinal detachment in a patient with lattice degeneration associated with atrophic hole has been estimated to be less than 0.3%. Interestingly, these retinal detachments occur more frequently in young, myopic patients, an observation possibly explained by the progressive strengthening of the bond between the retina and retinal pigment epithelium at the border of the hole with time.
Retinal tears are believed to stem from traction at the margins of lattice lesions, an area typified by tight vitreoretinal adhesion. This traction may originate from a posterior vitreous detachment, and as such, the retinal tear is often on the posterior margin of the lattice lesion. However, not all retinal tears occurring in eyes with lattice degeneration occur adjacent to a lattice lesion, suggesting that these eyes may be at a generalized increased risk of retinal tear. Estimates for the percentage of tears that do occur adjacent to lattice lesions range widely, from to 28 to 82.5%  Overall, the risk of retinal tear occurring adjacent to a lattice lesion is very low, with one study suggesting a 1% incidence after 10 years.
As mentioned previously, approximately 20 to 30% of patients with retinal detachment have evidence of lattice degeneration. Detachments associated with lattice degeneration more commonly occur due to retinal tears (16 to 18%) compared to atrophic round holes (range of 2.8 to 13.9%). Studies measuring the converse, i.e. the risk of development a retinal detachment in a patient wit lattice degeneration (though not necessarily from a lattice lesion-associated retinal break), have shown a fairly low overall risk ranging from 0.3 to 0.5%.
Patients with lattice degeneration are generally asymptomatic, whereby lattice degeneration is incidentally discovered. However, these patients may present with symptoms of sequelae, such as retinal tear of detachment. These symptoms may include photopsias, floaters, and/or loss of vision.
The long term chance of retinal detachment in patients with lattice is around 0.5%to 0.7%. On the other hand, one-third to 40% of patients with retinal detachments, without compounding factors such as surgery or other conditions, have been reported to have lattice.
A comprehensive ophthalmic exam is necessary for the purposes of identifying lattice lesions and differentiating them from retinal breaks or other pathologic findings. One great misconception about the clinical diagnosis of lattice degeneration is the prerequisite of lattice lines, a topic addressed by Dr. Norman Byer. Simply put: lattice lines are NOT required for the diagnosis of lattice degeneration. Dr. Byer resolves the matter succinctly, suggesting that any lesion whose borders demonstrate an "abrupt, discrete irregularity of the otherwise smooth surface of the retina" should be regarded as lattice degeneration, despite the great variety in morphologic features.
Nonetheless, typical findings of lattice degeneration include:
Lattice degeneration is defined to have one or more of the following features organized in accordance to their presumed frequency of occurrence: localized round, oval or linear shaped retinal thinning; pigmentation; whitish-yellow surface flecks; round, oval or linear white patches; round, oval or linear red craters; small atrophic round holes; branching white lines; yellow atrophic spots (depigmentation of pigment epithelium); and rarely tractional tears at the ends or posterior margins of lesions. Usually one, but sometimes two or more of these features predominate in each individual lesion. Presence of white lines is not necessary for the diagnosis of lattice degeneration. The so-called snailtrack degeneration, which has a snowflake-like appearance on its surface, was considered to be a variant of lattice degeneration by Dr. Normal Byer.
The observation of lesions in the peripheral retina suggestive of lattice must be carefully examined with scleral indentation and indirect ophthalmoscopy. The borders of lattice lesions will have an abrupt, discrete edge adjacent to otherwise normal retina.
Examples of various lattice lesions are shown below.
Lattice in itself is asymptomatic but may be associated with retinal tears, detachments, or traction that may present with photopsias, floaters, or visual disturbances.
Lattice degeneration is a clinical diagnosis, identified on dilated fundus examination typically using an binocular indirect ophthalmoscope, with or without the use of scleral depression [please see the "Physical Examination" section above]. Ancillary imaging may assist in identifying and documenting lattice degeneration. Conventional fundus cameras or wide-field imaging may be used for this purpose.
The clinical appearance of lattice is classically variable and may present as multiple morphologies in the same patient. Other conditions to consider that may appear similar in appearance include retinoschisis, atrophic holes, chorioretinal scarring, congenital hypertrophy of the retinal pigment epithelium, or other Peripheral Retinal Degenerations, most notably white without pressure or cystoid degeneration.
There are no measures to prevent the development of lattice degeneration.
There is no mandatory treatment for lattice degeneration alone. While it is associated with retinal holes, tears and detachments, it is not advocated to treat lattice lesions on a solely prophylactic basis.
There is currently no medical treatment for this condition.
When they are associated with retinal holes, tears or detachments, then the treatment of those conditions may dictate the course of action for lattice lesions. A simplified recommendation of treatment of peripheral retinal lesions according to the preferred practice pattern is available at https://www.aao.org/preferred-practice-pattern/posterior-vitreous-detachment-retinal-breaks-latti
Laser photocoagulation is the preferred treatment for lattice lesions at risk for retinal tears/detachment. Based on the risk for future tears or detachments, practitioners may decide to treat with other modalities such as cryotherapy or scleral buckling depending on their assessment of retinal detachment risk.
The prognosis for lattice degeneration in itself is good. The vast majority of patients will have lesions that are completely stable or slowly progressive. Patients who develop to retinal tears, detachments, and subsequent vitreoretinal traction should be treated as those conditions arise. Eyes with lattice (with or without holes) are at very low risk for retinal detachment overall. Eyes which develop at posterior vitreous detachment and/or a retinal tear are at risk for retinal detachment and those eyes require laser photocoagulation or cryotherapy to the horseshoe tear. 
- American Academy of Ophthalmology. AAO PPP Retina/Vitreous Committee, Hoskins Center for Quality Eye Care. Preferred Practice Pattern: Posterior Vitreous Detachment, Retinal Breaks, and Lattice Degeneration PPP 2019. October 2019 revision. Available at: https://www.aao.org/preferred-practice-pattern/posterior-vitreous-detachment-retinal-breaks-latti. Accessed 21st April 2020.
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